Microbial

Ecotoxicol Environ Saf, 1997 Dec, 38(3), 200 - 4
Microbial toxicity of Cd and Hg in different soils related to total and water-soluble contents; Welp G et al.; Microbial toxicity tests with Cd and Hg and up to 18 soil samples were combined with sorption and solubility measurements . The data ought to indicate to what extent toxic effects of the metals are influenced by sorption and the other factors that may alter their biocidal action . The microbial reduction of Fe(III) oxides to Fe2+ ions was used as a parameter of microbial activity to calculate the total amounts of Cd and Hg that cause 10, 50, and 90% inhibition {effective doses (ED)10, ED50, ED90} . The corresponding solution concentrations {effective concentrations: (EC)10, EC50, EC90} were derived from Freundlich adsorption isotherms . The very large variability in ED values in different soils (ED10: Cd, 5-95 mg/kg; Hg, 0.125-125 mg/kg) can be related to the sorption and solubility behavior of the metals . Nevertheless, the EC values of both metals also indicate a considerable variation (EC10: Cd, 0.01-1.13 mg/liter; Hg, < 0.001-0.041 mg/liter) . The influence of soluble soilborne substances on metal speciation is the main reason for their varying toxic potential in different soil solutions . The strong and complex influence of soil properties on the toxicity of heavy metals in soils indicates that both chemical and biological methods of soil analysis are needed to assess the risks of soil contamination adequately.

Acta Ophthalmol Scand, 1997 Oct, 75(5), 483 - 6
Corneoscleral discs excised from enucleated and non-enucleated eyes are equally suitable for transplantation; Garweg J et al.; PURPOSE: To assess whether the biological quality of corneoscleral tissue dissected in situ is, after organ culture, comparable to that harvested after enucleation . METHODS: Corneoscleral discs were prepared from 23 donor eyes, either after enucleation, under laminar flow conditions (right eyes; group 1) or by direct excision in situ (left eyes; group 2) . Endothelial cell counts were made and the degree of tissue contamination assessed both prior to and upon termination of organ culture . RESULTS: Microbial growth was found in 12/22 conjunctival swabs collected from group 1 eyes and in 14/22 of those obtained from group 2 globes (p = 0.76) . Bacterial growth was detected in four primary culture media, two from each group, at low colony densities . No significant difference in endothelial cell counts were encountered between the two groups, either immediately after dissection {group 1: 2940 +/- 308 (2100-3500) c/mm2; group 2: 2947 +/- 345 (2200-3700) c/mm2; p = 0.945} or upon termination of organ culture {group 1: 2646 +/- 321 (1895-3200); group 2: 2723 +/- 312 (2100-3650); p = 0.413} . CONCLUSION: Dissection of corneoscleral discs in situ may serve as an alternative to the conventional technique if consent is obtained to remove only the cornea . The risk of contamination is no higher and endothelial cell viability no lower than in tissue derived from enucleated globes, provided that the excision is performed by a skilled surgeon and a rigorous disinfection protocol is instigated.

Aliment Pharmacol Ther, 1997 Dec, 11 Suppl 3, 40 - 4; discussion 44-6
Review article: Epithelial disposition of antigen; Lamm ME; Exogenous antigens can impinge upon the luminal surface of mucous membranes and to a limited degree, can even penetrate into the lamina propria . As a result of infection, microbial antigens can be present in mucosal epithelium or lamina propria . At all three levels (lumen, epithelium, lamina propria), locally produced antibodies, principally immunoglobulin A (IgA), can combine with antigens . As a result, antigens can be prevented from attaching to the epithelium, viruses can be neutralized inside epithelial cells and immune complexes in the lamina propria can be excreted into the lumen . As the Fc portion of IgA is specialized to facilitate epithelial transport of IgA rather than to activate inflammatory mediator systems (as is the case with other classes of immunoglobulin), the predominance of IgA among mucosal antibodies serves to limit the degree of local inflammation following antigen-antibody reactions.

Microbios, 1997, 91(366), 55 - 65
Measurement of the dielectrophoretic enrichment of yeast on grid electrodes using image analysis; Brown AP et al.; Dielectrophoresis using grid electrode structures offers many advantages for the abstraction and enrichment of cells in analytical microbiology . Modifications to the quantification method of a grid-based dielectrophoresis system are described, utilizing a more rapid and efficient image analysis technique . The grid electrode arrangement enabled dielectrophoretic enrichment of Saccharomyces cerevisiae, resulting in between 36.2 and 46.1% concentration of cells (by a single pass), relative to an identical control sample suspension analysed without an applied electric field . These enrichment factors compare favourably with previously obtained data using alternative measurement techniques . In addition, the image analysis technique is considerably less labour intensive and enables the continuous detection of cellular concentration and dielectrophoretic behaviour . Utilizing differences in frequency dependent cell responses, the system described could be suitable for highly selective pre-enrichment or cell separation on a large scale . Dielectrophoretic techniques, including enrichment, viable cell analysis and assessment of low microbial concentrations, could enhance or replace many existing methods for the analysis of micro-organisms and other cells.

Analyst, 1997 Oct, 122(10), 1125 - 8
Microbial detection by a glucose biosensor coupled to a microdialysis fibre; Palmisano F et al.; The use of a glucose biosensor coupled to microdialysis sampling in a flow injection analysis system is described to follow the growth of Escherichia coli in a glucose-containing liquid culture medium . The experimental set-up permitted a throughput rate of 25 samples h-1 . Growth curves were modelled by a modified Gompertz equation, which permitted the determination of lag time and maximum specific growth rate . The time required to produce an appreciable variation in the biosensor response (minimum detection time, MDT) was determined . A plot of MDT versus microbial concentration was found to be linear in the range 10(6)-10(10) colony forming units (cfu) ml-1 . A microbial concentration of 10(6) cfu ml-1 can be detected after about 5 h.

Trans R Soc Trop Med Hyg, 1997 Sep-Oct, 91(5), 618 - 22
Higher proportion of CD8+ T cells in the blood in healthy adults from Ethiopia and Bangladesh compared with Sweden; Worku S et al.; The phenotypic composition of peripheral blood lymphocytes in 45 healthy adults (15 each from Bangladesh, Ethiopia and Sweden) was analysed as an indicator of the influence of environment and/or ethnic background on the human immune response . The possible interference of technical factors was minimized by highly standardized handling of samples and by use of a similar simultaneous 3-colour flow cytometry analysis technique for all samples . The percentage of CD4+ cells was lower, and the percentage of CD8+ cells was higher, in Bangladeshi and Ethiopian subjects than in those from Sweden . A higher percentage of CD57+/CD8+ T cells was also found in these 2 groups than in Swedish subjects . The percentage of gamma delta T cells was higher in Bangladeshi subjects and a difference in T cell receptor V beta expression was also noted between Bangladeshi and Swedish subjects . The data suggest that environmental or genetic factors are important bias factors to be considered in immunophenotyping studies . Possibly differences in the pattern or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response . The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be important in the development of new strategies of medical intervention in different geographical regions or ethnic groupsPIP: The phenotypic composition of peripheral blood lymphocytes in 45 healthy adult blood donors (15 each from Bangladesh, Ethiopia, and Sweden) was examined as an indicator of the influence of environment and/or ethnic background on the human immune response . A highly standardized 3-color flow cytometry analysis was performed on all samples . The percentage of CD4+ cells was lower and the percentage of CD8+ cells was higher in Bangladeshi and Ethiopian subjects than in those from Sweden . A higher percentage of CD57+/CD8+ T cells was likewise found in these 2 groups compared to Swedish subjects . The percentage of gammadelta T cells was higher in Bangladeshi subjects and a difference in T cell receptor Vbeta expression was also noted between Bangladeshi and Swedish subjects . The findings suggest that environmental or genetic factors are important bias factors to be taken into account in phenotyping studies . Possible variations in the patterns or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response . The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be essential in the development of new medical intervention approaches in different geographical regions or ethnic groups .

Biochim Biophys Acta, 1998 Jan 15, 1389(2), 123 - 31
Inhibition of lipases from Chromobacterium viscosum and Rhizopus oryzae by tetrahydrolipstatin; Potthoff AP et al.; Tetrahydrolipstatin is known as an inhibitor for pancreatic lipase but not for microbial lipases . In this paper we demonstrate that in the presence of water-insoluble substrates like tributyrin or olive oil, tetrahydrolipstatin inhibits the lipases of Chromobacterium viscosum and Rhizopus oryzae, although with different potency . In contrast to porcine pancreatic lipase, which forms an irreversible and covalent enzyme-inhibitor complex with tetrahydrolipstatin, the inhibition of the microbial lipases is reversible as the inhibitor can be removed from the enzyme-inhibitor complex by solvent extraction . Moreover, after inhibition of Chromobacterium viscosum lipase tetrahydrolipstatin remains chemically unchanged.

Zh Mikrobiol Epidemiol Immunobiol, 1997 Nov-Dec, (6), 59 - 61
{The characteristics of the changes in the submicroscopic structure of the immunocompetent cells in the development of experimental mycobacterioses}; Sibirnaia RI et al.; The electron-microscopic study of the ultrastructure of peritoneal exudate cells of laboratory animals during the development of infectious processes caused by Mycobacterium tuberculosis and atypical mycobacteria was carried out . The study revealed that in all pathological processes under study typical manifestation of cell-mediated immunity took place, characterized by microbial phagocytosis on the level of cell ultrastructure, an increase in the lysosomal activity and the exhaustion of cells involved in the process up to their destruction . These changes in processes caused by the action of the agents of different mycobacterial infections were manifested with different intensity.

Bioorg Med Chem, 1997 Dec, 5(12), 2165 - 71
O-methylasparvenone, a nitrogen-free serotonin antagonist; Bos M et al.; O-Methylasparvenone (1) and asparvenone (2) were isolated from an Aspergillus parvulus Smith broth in a microbial screening for 5-HT2C ligands and found to be 5-HT2C antagonists . They represent the first nitrogen-free serotonin ligands . The absolute configuration of 1 was determined to be S by X-ray analysis of the corresponding Mosher-ester . A short and efficient synthesis of rac-1 was developed . This protocol was applied to the synthesis of derivatives of 1 and a structure-affinity relationship was established.

Proc Natl Acad Sci U S A, 1997 Dec 9, 94(25), 13414 - 9
Catalytic mechanism of the adenylyl and guanylyl cyclases: modeling and mutational analysis; Liu Y et al.; The adenylyl and guanylyl cyclases catalyze the formation of 3', 5'-cyclic adenosine or guanosine monophosphate from the corresponding nucleoside 5'-triphosphate . The guanylyl cyclases, the mammalian adenylyl cyclases, and their microbial homologues function as pairs of homologous catalytic domains . The crystal structure of the rat type II adenylyl cyclase C2 catalytic domain was used to model by homology a mammalian adenylyl cyclase C1-C2 domain pair, a homodimeric adenylyl cyclase of Dictyostelium discoideum, a heterodimeric soluble guanylyl cyclase, and a homodimeric membrane guanylyl cyclase . Mg2+ATP or Mg2+GTP were docked into the active sites based on known stereochemical constraints on their conformation . The models are consistent with the activities of seven active-site mutants . Asp-310 and Glu-432 of type I adenylyl cyclase coordinate a Mg2+ ion . The D310S and D310A mutants have 10-fold reduced Vmax and altered {Mg2+} dependence . The NTP purine moieties bind in mostly hydrophobic pockets . Specificity is conferred by a Lys and an Asp in adenylyl cyclase, and a Glu, an Arg, and a Cys in guanylyl cyclase . The models predict that an Asp from one domain is a general base in the reaction, and that the transition state is stabilized by a conserved Asn-Arg pair on the other domain.

Z Gastroenterol, 1997 Aug, 35(8), 637 - 49
{Nutrition in the etiopathogenesis of chronic inflammatory bowel diseases}; Weinand I et al.; It is currently held that the pathogenesis of inflammatory bowel disease (IBD) involves a complex interaction of host responses, some immunologic and genetically determined, and external influences including microbial and dietary factors . Nutritional surveys and studies testing stepwise exclusion dietary compounds have suggested that dietary factors might be linked to the occurrence of IBD . Food allergy was suggested early as a possible trigger for the inflammatory response; however, no firm evidence has been gathered over the years to substantiate this possibility . The possibility that patients with Crohn's disease may have an unusual premorbid pattern of dietary intake has also been examined since the early seventies . Several groups of investigators report a high intake of refined sugars (i.e . sucrose), recycled cooking oil, a more frequent consumption of fast foods in patients with Crohn's disease and ulcerative colitis respectively . However, a critical comparison of incidence and prevalence studies published from 1976 until 1994 clearly showed no pre-existing nutritional abnormality that has been identified consistently in patients who develop inflammatory bowel disease.

Prikl Biokhim Mikrobiol, 1997 Jul-Aug, 33(4), 455 - 60
{A bioluminescent method of determining antibiotic sensitivity of microbial cells in septic blood}; Frundzhian VG et al.; A bioluminescence assay for rapid (5-7 h) determination of susceptibility to antibiotics was applied to samples of septic blood and optimized . The method comprises hemolysis of blood, reduction of osmolarity by adding concentrated nutritive media, and further incubation of the samples in the presence or absence of therapeutic doses of the antibiotic examined . Growth of bacteria is estimated by the level of bacterial ATP in the sample, which is determined by a bioluminescence assay . Hemolysis and further incubation of samples in nutrition media reduced the concentration of nonbacterial ATP to a level that did not interfere with the determination of bacterial ATP . There was a positive correlation between the levels of resistance to antibiotics determined by the bioluminescence assay and standard plate counts.

G Ital Med Lav Ergon, 1997 Jan-Mar, 19(1), 33 - 5
{Reduction of the lung cancer risk among dairy ranchers: dose response relationship with the traditional indicators of professional exposure}; Mastrangelo G et al.; An epidemiological study of mortality was carried out in the Province of Padua in a cohort of family farmers . The subjects, identified from the SCAU files, were enrolled in the cohort if informations were available on complete registry data, date of beginning and of termination of farm work, size of farm, and number of dairy cattle . The 2,415 farmers selected were followed-up for mortality through the registry offices of their Communes of residence . The cause of death was obtained for the 541 decedents . The standardised mortality ratio (SMR) was the ratio between observed and expected mortality, calculated on the basis of the mortality rates in the regional general population . The lung cancer SMR was 0.54 (0.36-0.79; observed = 27) among the 1641 dairy farmers, and 0.78 (0.46-1.25; observed = 17) among the 774 arable farmers . Among dairy farmers, moreover, lung cancer SMRs showed a significant trend across the quartiles of length of work, number of cattle, area of farm, age at beginning farm work, and age at work termination . Dairy farmers are known to be exposed to higher airborne endotoxin concentrations, and it is reasonable to assume that this cumulative exposure further increases with years of work, number of cattle, and area of farm . Microbial endotoxin might have protected dairy farmers against lung cancer through a host factor, the Tumor Necrosis Factor, produced by alveolar macrophages.

Plant Mol Biol, 1997 Nov, 35(5), 673 - 9
In vivo characterization of transcriptional regulatory sequences involved in the defence-associated expression of the tobacco retrotransposon Tnt1; Vernhettes S et al.; The expression of the tobacco retrotransposon Tnt1 is induced by wounding, pathogen infections as well as microbial elicitors and abiotic factors known to induce the plant defence response . We report here that the LTR U3 region is sufficient to mediate transcriptional activation by biotic and abiotic elicitors in stable transgenic conditions . We have used in vivo footprinting techniques in order to analyse the cis-regulatory elements of the LTR U3 region that mediate the induction of Tnt1 expression . Our results indicate that a tandemly repeated short element, named BII box, is involved in the transcriptional activation of the tobacco retrotransposon Tnt1 in association with the plant defence signaling cascade.

Plant Mol Biol, 1997 Nov, 35(5), 551 - 60
Isolation of the cDNAs encoding (+)6a-hydroxymaackiain 3-O-methyltransferase, the terminal step for the synthesis of the phytoalexin pisatin in Pisum sativum; Wu Q et al.; Pisatin is the major phytoalexin produced by pea upon microbial infection . The enzyme that catalyzes the terminal step in the pisatin biosynthetic pathway is (+)6a-hydroxymaackiain 3-O-methyltransferase (HMM) . We report here the isolation and characterization of two HMM cDNA clones (pHMM1 and pHMM2) made from RNA obtained from Nectria haematococca-infected pea tissue . The two clones were confirmed to encode HMM activity by heterologous expression in Escherichia coli . The substrate specificity of the methyltransferases in E . coli was similar to the activity detected in CuCl2-treated pea tissue . Nucleotide sequence analysis of Hmm1 and Hmm2 revealed an open reading frame of 1080 bp and 360 amino acid residues which would encode 40.36 kda and 40.41 kDa polypeptides, respectively . The deduced amino acid sequence of HMM1 has 95.8% identity to HMM2, 40.6% identity to Zrp4, a putative O-methyltransferase (OMT) in maize root, and 39.1% to pBH72-F1, a putative OMT induced in barley by fungal pathogens or UV light . Comparison of the deduced amino acid sequences of the cDNA clones to OMTs from other higher plants identified the binding sites of S-adenosylmethionine (AdoMet) . Southern blot analysis showed two closely linked genes with strong homology to Hmm in the pea genome.

J Hosp Infect, 1997 Dec, 37(4), 263 - 72
How useful are microbial filters in respiratory apparatus?
Das I, Fraise AP.
Following an outbreak of hepatitis C in surgical patients in Australia, it has been suggested that transmission can take place as a result of contaminated anaesthetic circuits . It has therefore been recommended that filters should be placed between patients and breathing systems with a new filter being used for each patient . Although nosocomial pneumonia is a major manifestation of hospital-acquired infection, it is unclear whether contamination of ventilator circuits is implicated in the aetiology of this condition . Some data suggest that bacteria cannot survive well in anaesthetic circuits and several studies have failed to demonstrate significant contamination of circuits in clinical situation . Several outbreaks of pneumonia related to contaminated anaesthetic equipment have been described, but many of these were controlled by appropriate decontamination of the respiratory equipment . Although ventilator filters are used by the majority of intensive care units and filters do have the ability to filter bacteria and viruses, there are few data suggesting that the use of filters reduce the rate of pulmonary infections in long-term ventilated patients . Furthermore, to change filters between operations would have significant financial implications, and there is no conclusive evidence that they would reduce cross infection . Until more data are available on the role of filters in both long-term ventilated patients and operations, standard hygienic measures such as appropriate disinfection protocols are still the most effective way of reducing ventilator-associated infections.

Rev Med Chir Soc Med Nat Iasi, 1996 Jul-Dec, 100(3-4), 193 - 7
The patients with cariogenic high-risk after the cervico-facial radiotherapy and their management; Lacatusu S et al.; Studying through clinical and laboratory means the bucco-dental status of the 28 patients who followed radiotherapeutical cures in the cervico-facial territory, the authors establish the apparition, at different periods of time, of the rampant caries . The rampant caries have been found in 46.42 percent of the cases, especially in patients exposed to prolonged or repeated cures of cervico-facial radiotherapy (88.88 percent) and concern the cervical zones, incisal edges and cusps, zones that are usually resistant at caries . The appearance and the severity of these types of caries are correlated with: a) the degree of reduction of the repose and stimulated salivary flow; b) the maintaining time of the low salivary flow that is dependent on the received X-ray dose and the number of cures; c) the association with sweet-drinks intake; d) the manner of effectuation of the bucco-dental hygiene; e) the setting-up or not of the some prevention measures . There are presented some preventive measures that must be set-up in this category of patients and treatment-protocols, that can be applied in the clinical situations of appearance of rampant caries after the irradiant treatment of the head and neck . The authors recommend the compulsory use of the prophylactic treatment and suggest a suitable plan of treatment that includes the reduction of microbial flora, the change of the alimentary diet, and salivary stimulates and substitutes . These measures can avoid the apparition of rampant caries, which will require ample restoration . The conclusions emphasize the fact that exists real possibilities of protection and treatment for these types of caries, depending on the clinical status of patient and the disease prognosis, when exists a tight collaboration between the radiotherapist, patients, and dentist.

Avian Dis, 1997 Oct-Dec, 41(4), 977 - 80
Transmission electron microscopic demonstration of abnormalities on the tracheal cilia of chicks exposed to formaldehyde during hatching; Sander JE et al.; Formaldehyde gas used to fumigate hatcheries for control of microbial contamination has an adverse effect on tracheal cilia function and morphology . Evaluation of the changes revealed alterations in the ultrastructure of the axoneme with the absence of B subfibers and the production of additional A subfibers . Spikes and vesicular blebs in the cilia walls were evident in formaldehyde-exposed cilia . These changes could result in ciliastasis and cilia loss.

Biochem Pharmacol, 1998 Jan 15, 55(2), 105 - 11
Multiple controls in inflammation . Extracellular and intracellular phospholipase A2, inducible and constitutive cyclooxygenase, and inducible nitric oxide synthase; Cirino G; Inflammation occurs as a defensive response to invasion of the host by foreign material, often of microbial nature . This response is normally a localized protective response that at the microscopic level involves a complex series of events including dilatation of arterioles, venules, and capillaries with increased vascular permeability, exudation of fluids including plasma proteins, and leukocyte migration into the inflammatory area . Since disease characterized by inflammation is an important cause of morbidity and mortality in humans, the processes involved in the host defense in inflammation have been and continue to be the object of several experimental studies . The role of several mediators such as histamine, serotonin, bradykinin, prostaglandins, and, more recently, cytokines and nitric oxide has been evaluated, and a contribution for each one of these mediators has been proposed . With the development of powerful molecular biology tools, it has become possible to study enzymes involved in this complex phenomenon by measuring the expression or evaluating the signaling pathways following a specific stimulus . These techniques have generated a proliferation of studies on the role of several enzymes and cytokines in inflammation . Most of these studies have been conducted in vitro on cell lines, and not many of the results have been confirmed by in vivo studies . This commentary does not pretend to analyze all of the studies and their possible in congruences, but endeavors to provoke in the reader a critical review of dogmas and current beliefs that most of the time are built on unilateral interpretation of the data.

Leukemia, 1997 Dec, 11(12), 2131 - 6
Expression of NADPH oxidase is induced by all-trans retinoic acid but not by phorbol myristate acetate and 1,25 dihydroxyvitamin D3 in the human promyelocytic cell line NB4; N'Diaye EN et al.; Human promyelocytic cells, NB4, differentiate into neutrophils in response to all-trans retinoic acid (ATRA) . It has recently been proposed that NB4 cells have bilineage potential because these cells are also able to differentiate into monocyte/macrophages when exposed to a combination of 1,25-dihydroxyvitamin D3 (VD3) and phorbol myristate acetate (PMA) . Differentiation of myeloid cells into neutrophils or monocytes is associated with the acquisition of the O2- producing enzyme, NADPH oxidase, which plays a critical role in microbial killing . In this study, the expression of the components of the NADPH oxidase complex during the differentiation of NB4 cells into neutrophils or macrophages has been investigated . Whereas cells exposed to ATRA were able to produce O2- after 2 days of differentiation, they remain unable to generate O2- when exposed to PMA or PMA + VD3 . With the exception of p21rac, none of the other oxidase components was expressed in non-differentiated cells . Addition of ATRA induced the progressive expression and accumulation of p22phox, p91phox, p47phox and p67phox . Compared to the other components, p67phox was expressed late and its expression appeared to correlate most closely with the generation of O2- in the differentiation process . In PMA or PMA + VD3-differentiated NB4 cells, expression of the NADPH oxidase components was incomplete . Therefore, ATRA induced the expression of a functional NADPH oxidase complex in neutrophil-like NB4 cells . In contrast, when NB4 cells are exposed to monocytic differentiating agents, they acquire only part of the phenotypic characteristics of monocytes and lack one of the major phagocytic functionalities, the respiratory burst oxidase.

Arch Oral Biol, 1997 Oct-Nov, 42(10-11), 735 - 42
Scanning electron microscopy of microbial colonization of 'rapid' and 'slow' dental-plaque formers in vivo; Zee KY et al.; The aim was to investigate the morphological features of supragingival plaque development in 'rapid' and 'slow' plaque formers using scanning electron microscopy (SEM) . Forty-nine healthy volunteers were screened for their plaque-formation rate after 3 days of oral hygiene abstinence using the Plaque Index (PI) . Five with the highest and six with the lowest mean PI were selected as 'rapid' and 'slow' plaque formers, respectively . Six enamel blocks measuring 2 x 2 x 1 mm were bonded onto the buccal surfaces of the upper left canine, premolars and first molar of each selected participant after a series of prophylaxes and oral hygiene instruction to ensure clinical gingival health . A 14-day period with no oral hygiene began thereafter . An enamel block was removed at 3 hr, 6 hr, 1 day, 3 days, 7 days and 14 days from each individual, fixed, and processed for SEM . Quantitatively, more bacteria were observed on the 3-hr to 1-day enamel blocks of the 'rapid' plaque formers . The day-1 specimens of the 'rapid' group showed a more complex supragingival plaque structure than those of the 'slow' group . From days 3 to 14, during the maturation period of supragingival plaque, there were no discernible differences between the two groups except that intermicrobial matrix was more prominent in the 'rapid' group . In general, the development of supragingival plaque followed known patterns . These observations indicate that morphological features of supragingival plaque in 'slow' and 'rapid' plaque formers differ, especially in the early developmental phases.

Med Parazitol (Mosk), 1997 Oct-Dec, (4), 32 - 6
{The isolation and results of the study of the protein structure of spirochetes isolated from I . ricinus ticks in Byelarus}; Trofimov NM et al.; Four hundred and eighty Ixodes ricinus (278 female and 202 male) samples collected in the natural biotopes of 13 administrative districts in southwest Byelarus were studied via DSK-H medium (Sigma) inoculation . Twenty-four spirochetes isolates (3, 2, 1, and 18 in the Brest, Gomel, Mogilev, and Grodno regions, respectively) were obtained on the territory of Byelarus . After adapted to the medium, most isolates (as many as 7 x 10(6)-5 x 10(7) microbial cells per ml) in the stationary phase . All the obtained isolates were cryoconserved at the level of 2-6 passages and after -70 degrees C storage during 4-6 months (a followup period) they were able to recover their initial reproductive activity in the fresh BSK-H medium . Proceeding from preidentification using a comparative electrophoretic analysis of the molecular mass of polypeptides, the pattern of their specific reactivity with polyclonal serum antibodies from the rabbit immunized with cultured Borrelia afzelii (Ip21 strain), in immunoblotting and indirect immunofluorescence assay, I . ricinus spirochetes were referred to Borrelia burgdorferi sensu lato isolates.

Regul Toxicol Pharmacol, 1997 Dec, 26(3), 307 - 21
Health risk assessment practices in the U.S . Food and Drug Administration; Gaylor DW et al.; The U.S . Food and Drug Administration (FDA) regulates a wide variety of consumer products . Safety issues involve chemical and microbial contaminants in food, biologies, and medical devices; side effects from prescription and nonprescription drugs; residues of animal drugs in food; and radiation from electronic devices . Because of this wide diversity, the legal standards, rules, and policies governing the regulation of these products differ considerably . Hence, risk assessment and risk management practices within the FDA are of necessity quite diverse . This paper presents a summary of risk assessment practices at each of the product centers of the FDA (Center for Food Safety and Applied Nutrition, Center for Drug Evaluation and Research, Center for Biologics Evaluation and Research, Center for Devices and Radiological Health, and Center for Veterinary Medicine) and of the development of risk assessment procedures at the National Center for Toxicological Research.

J Bacteriol, 1998 Jan, 180(2), 400 - 2
Detoxification of protoanemonin by dienelactone hydrolase; Bruckmann M et al.; Protoanemonin is a toxic metabolite which may be formed during the degradation of some chloroaromatic compounds, such as polychlorinated biphenyls, by natural microbial consortia . We show here that protoanemonin can be transformed by dienelactone hydrolase of Pseudomonas sp . strain B13 to cis-acetylacrylate . Although similar Km values were observed for cis-dienelactone and protoanemonin, the turnover rate of protoanemonin was only 1% that of cis-dienelactone . This indicates that at least this percentage of the enzyme is in the active state, even in the absence of activation . The trans-dienelactone hydrolase of Pseudomonas sp . strain RW10 did not detectably transform protoanemonin . Obviously, Pseudomonas sp . strain B13 possesses at least two mechanisms to avoid protoanemonin toxicity, namely a highly active chloromuconate cycloisomerase, which routes most of the 3-chloro-cis,cis-muconate to the cis-dienelactone, thereby largely preventing protoanemonin formation, and dienelactone hydrolase, which detoxifies any small amount of protoanemonin that might nevertheless be formed.

Epidemiol Infect, 1997 Dec, 119(3), 319 - 25
Residual moisture determines the level of touch-contact-associated bacterial transfer following hand washing; Patrick DR et al.; We report here a new and critical determinant of the effectiveness of hand hygiene procedures, namely the amount of residual moisture left on the hands after washing and drying . When samples of skin, food and utilities were touched with wet, undried hands, microbial numbers in the order of 68000, 31000 and 1900 respectively translocated to these representative surfaces . Bacterial numbers translocating on touch contact decreased progressively as drying with an air or cloth towel system removed residual moisture from the hands . A 10 s cloth towel-20 s air towel protocol reduced the bacterial numbers translocating to skin, food and utilities on touch contact to 140, 655 and 28 respectively and achieved a 99.8, 94 and 99% reduction in the level of bacterial translocation associated with wet hands . Careful hand drying is a critical factor determining the level of touch-contact-associated bacterial transfer after hand washing and its recognition could make a significant contribution towards improving handcare practices in clinical and public health sectors.

Genetica, 1997, 100(1-3), 241 - 52
The expression of the tobacco Tnt1 retrotransposon is linked to plant defense responses; Grandbastien MA et al.; Activation of retrotransposons by stresses and external changes is common in all eukaryotic systems, including plants . The transcription of the tobacco Tnt1 retrotransposon was studied in its natural host as well as in Arabidopsis and tomato . It is activated by factors of microbial origin, by external stresses, and by viral, bacterial, and fungal attacks . Tnt1 expression is linked with the biological responses of the plant to the elicitor or to the pathogen attack and in particular with the early steps of the metabolic pathways leading to the activation of plant defense genes . In most cases, the basic features of Tnt1 regulation in tobacco are maintained in tomato and Arabidopsis, but some host-specific regulations were shown . The U3 region of the Tnt1 LTR contains the major cis-acting components of Tnt1 transcriptional activation in association with the plant defense responses . Furthermore, the Tnt1 U3 region, and especially the tandemly repeated BII boxes, contains several sequences similar to well-characterized motifs involved in the activation of several plant defense genes . The possible origin of Tnt1 regulatory sequences as well as the biological implications of Tnt1 activation by pathogen attacks are discussed.

Arch Biochem Biophys, 1998 Jan 1, 349(1), 161 - 6
Site-directed mutagenesis of bacterial hemoglobin: the role of glutamine (E7) in oxygen-binding in the distal heme pocket; Dikshit KL et al.; The bacterial and yeast hemoglobins have a glutamine instead of histidine in the E7 position of the distal heme pocket . The recently determined crystal structure of Vitreoscilla hemoglobin (VHb) indicates that this residue is oriented out of the heme pocket and may not ligand the bound oxygen . This is in contrast to elephant myoglobin which also has a Gln(E7) but which does ligand the bound oxygen . This residue was changed in VHb using site-directed mutagenesis to leucine (VHbL) or to histidine (VHbH) . Spectral and kinetic studies of the binding of oxygen and CO to VHbL showed that this substitution had little effect on the ligand-binding properties of this protein, evidence that Gln(E7) does not H-bond the bound ligand, in agreement with the findings of the crystallographic study of VHb . In contrast, the functional properties of VHbH were drastically altered in a way suggesting that the E7His may itself be liganded to the heme iron . These studies are further evidence that the distal heme pocket in VHb and related microbial hemoglobins differs from that in mammalian hemoglobins and may resemble in some ways the heme pocket in cytochrome b5.

Am J Ophthalmol, 1997 Sep, 124(3), 394 - 5
Corneal ulcer associated with contamination of aerosol saline spray tip; Donzis PB; PURPOSE: To report a complication of aerosol saline use in a contact lens wearer . METHODS: Case report . A 57-year-old woman who used soft contact lenses on an extended-wear basis developed a unilateral Pseudomonas corneal ulcer associated with the use of preservative-free aerosol saline . RESULTS: The solution inside the aerosol can was free of microbial contamination . The spray tip, however, was contaminated with P aeruginosa . CONCLUSIONS: Aerosol spray cans may minimize contamination of the solution inside the can . The spray tip is still susceptible to microbial contamination, especially with continued use of the solution over an extended period of time.

J Dairy Sci, 1997 Dec, 80(12), 3283 - 92
Effects of dietary supplementation on nutrient digestion and the milk yield of intensively grazed lactating dairy cows; Jones-Endsley JM et al.; Fourteen midlactation Holstein cows were used in an 80-d study to examine supplementation strategies during intensive rotational grazing . Factors examined were the concentration of protein in the supplement {12 or 16% crude protein (CP) on a dry matter basis} and the amount of supplement offered (6.4 or 9.6 kg/d per cow) . The supplement was offered in equal portions three times daily after milking . Pasture, composed of alfalfa (Medicago sativa) and orchardgrass (Dactylis glomerata), was divided into 27 0.16-ha paddocks that were grazed for 12 to 24 h . Intake of forage tended to increase as CP in the supplement increased but was unaffected by the amount of supplement offered . Intakes of organic matter and dry matter and the digestion of these nutrients in the total tract increased as CP in the supplement increased and as the amount of supplement increased . Ruminal pH and concentrations of volatile fatty acids were unaffected by treatments, but concentrations of NH3 N increased as CP in the supplement increased . An increase in CP resulted in a greater intake and flow of total N to the duodenum . The flow of microbial N to the duodenum and the efficiency of microbial protein synthesis were unaffected by treatment . Flows of total amino acids and essential amino acids to the duodenum tended to increase as CP in the supplement increased . Yield of fat-corrected milk and concentrations of fat and protein in milk were unaffected by treatment . These results suggested that the supply and digestion of nutrients in grazing dairy cows may be improved through an increase in the CP concentration of the supplement or the amount of supplement offered . However, effects on the yield of milk and milk components may be small.

Adv Biochem Eng Biotechnol, 1998, 59, 73 - 121
Novel screen methodologies for identification of new microbial metabolites with pharmacological activity; Hill DC et al.; Micro-organisms continue to provide an important source of chemical diversity for the discovery of compounds with new biological activities . Microbial metabolites discovered recently using assays to detect compounds with potential pharmacological utility are surveyed and found to represent an extensive range of structural types produced by a wide variety of organisms . Assays used for screening samples produced by microbial processes must be robust, sensitive and specific and able to operate above a background of potential interferences from a number of sources . Discovery assays currently in use fall into three main categories cell-based, receptor-ligand interaction and enzyme inhibition assays . Trends in the use of these assays and new developments in assay technology applicable to the screening of microbial samples are examined with particular reference to the high throughput screening environment . For microbial screening to be a competitive route to new drug leads, the disciplines involved must be engineered into a seamlessly integrated process to deliver novel compounds with the required biological properties rapidly.

Appl Environ Microbiol, 1998 Jan, 64(1), 185 - 91
Use of subtractive hybridization to design habitat-based oligonucleotide probes for investigation of natural bacterial communities; Mau M et al.; We describe a rapid oligonucleotide probe design strategy based on subtractive hybridization which yields probes for 16S rRNA or rRNA genes of individual members of microbial communities that are specific within the context of those communities . This strategy circumvents the need to sequence many similar or identical clones of dominant members of a community . Radioactively labeled subfragments of a cloned 16S rRNA gene sequence for which a probe is required (target) were hybridized with biotinylated total 16S ribosomal DNA (rDNA) amplified from the microbial community, and the hybrids formed were subsequently discarded . The remaining enriched fragments were used to screen a library consisting of cloned subfragments of the target sequence by colony hybridization in order to identify the variable regions of the 16S rRNA gene with the required specificity . The sequencing of random clones in one 16S rDNA library demonstrated that only those clones with 100% sequence identity with the probe fragment were detected by it . Moreover, sequencing of other, randomly selected, probe-positive clones revealed 100% sequence identity with the probe . Probes developed in this way tended to correspond to more variable regions of the 16S rRNA if the target sequences were similar to the sequences of other clones in the library and to less variable regions if the target sequences were phylogenetically isolated within the clone library . Although the absolute specificity of the latter probes, as assessed by comparison with available database sequences, was lower than the absolute specificity of the probes from the more variable regions, they were specific within the context of the environmental samples from which they were derived.

Ophthal Plast Reconstr Surg, 1997 Dec, 13(4), 289 - 92
Conjunctival cilia entrapment: an unrecognized cause of ocular irritation; Hunts JH et al.; Conjunctival entrapment of cilia is form of ocular irritation that to our knowledge has not yet been described . Scarring predisposes the conjunctiva to this phenomenon by creating blind recesses in which loose cilia can become entrapped . Once caught, the rigid cilia can act as a mechanical irritant or act as a nidus for microbial growth . We present herein three patients with entrapped cilia and discuss their pathophysiology and management . The symptoms in all three patients resolved with conjunctivoplasty and removal of the cilia.

Phytochemistry, 1997 Dec, 46(7), 1193 - 5
Glucose-conjugation of the flavones of Psiadia arabica by Cunninghamella elegans; Ibrahim AR et al.; Microbial transformation of psiadiarabin and its 6-desmethoxy analogue 5,3' dihydroxy-7,2',4'5'-tetramethoxyflavone by Cunninghamella elegans NRRL 1392 gave the 3'-glucoside conjugates of the two flavones . Structural elucidation of these two new metabolites was achieved using 1D and 2D NMR spectroscopy and CIMS.

Shock, 1997 Dec, 8(6), 391 - 401
Wound healing in sepsis and trauma; Thornton FJ et al.; Wound healing represents a dynamic and immediate response of the body to tissue injury with the purpose of restoring anatomical continuity, structure and function . Success or failure of this complex cascade of events is determined largely by competence of the host's immune system . Sepsis represents one of the most formidable threats to successful wound healing . It can present as a local bacterial colonization of the injury site with minimal systemic reaction or the "systemic inflammatory response syndrome," a primary cause of mortality among critically ill patients . Trauma also predisposes patients to wound complications especially as a result of post-traumatic immunosuppression . This phenomenon exposes the patient to the risk of microbial infection and ultimately the sepsis syndrome . The immune system, therefore, represents a vulnerable gateway through which trauma and sepsis exert their deleterious effect on the wound healing process resulting in increased morbidity and mortality for the surgical patient.

Electrophoresis, 1997 Oct, 18(11), 2019 - 23
Sodium dodecyl sulfate-polymer capillary electrophoresis for the analysis of cell culture proteins; Klyushnichenko V et al.; The application of sodium dodecyl sulfate (SDS)-polymer capillary electrophoresis (CE) to the analysis of proteins of hybridoma cell culture supernatant is demonstrated . All steps of the developed analysis are shown and discussed . Following optimization of sample preparation and concentration, as well as of the mode of injection all main protein components were separated with high resolution and selectivity . Proteolytic degradation of IgG, due to microbial contamination, was observed on SDS-gel CE and capillary zone electrophoresis (CZE) . The technique was applied to monitor the cell cultivation process and concentrations of main components are demonstrated . IgG was found to increase from initially 5 mg/L to 20 mg/L after 4 days and to > 130 mg/L after 14 days of cultivation . The techniques may be applied to other biotechnological processes for the production or purification of proteins.

Crit Rev Immunol, 1997, 17(5-6), 469 - 80
Initiation and regulation of CNS autoimmunity; Goverman J et al.; Our studies addressed the questions of how self-reactive T cells escape tolerance and what stimuli cause these T cells to initiate autoimmune responses . We employed experimental allergic encephalomyelitis (EAE) as an animal model of multiple sclerosis (MS) . Endogenous expression of myelin basic protein (MBP) induces tolerance in T cells that recognize one region of MBP, whereas T cells specific for a different region escape tolerance . Triggers of disease induction were investigated in a T-cell receptor (TCR) transgenic model in which the majority of T cells recognize the MBP epitope that does not induce tolerance . EAE occurs spontaneously in this model and the incidence of disease depends on microbial exposure . EAE can also be actively induced by immunization with MBP peptide accompanied by injection of pertussis toxin as well as by administration of pertussis toxin alone . Immunization with MBP peptide without pertussis toxin, however, stimulates the transgenic T cells, but the activated T cells do not accumulate in the central nervous system (CNS) or induce EAE . Our studies suggest that initiation of autoimmune disease involves complex interactions between the neuroendocrine system as well as the innate and specific immune systems.

J Infect Dis, 1998 Jan, 177(1), 182 - 7
Pneumocystis carinii glycoprotein A inhibits surfactant phospholipid secretion by rat alveolar type II cells; Lipschik GY et al.; Pneumocystis carinii pneumonia (PCP) remains a major cause of morbidity in AIDS . The pathogenesis of PCP is poorly understood, but evidence of surfactant abnormalities is mounting . The role of the major surface glycoprotein of P . carinii, gpA, in producing surfactant abnormalities was investigated . Rat type II pneumocytes were incubated with {3H}choline, purified gpA, and modulators . Lipid was extracted, and {3H}dipalmitoyl phosphatidylcholine (DPPC) secretion was calculated . Contaminating endotoxin had no effect on DPPC secretion . gpA inhibited basal and ATP-stimulated DPPC secretion in a dose- and time-dependent manner . An anti-gpA monoclonal antibody attenuated inhibition of DPPC secretion . Unglycosylated recombinant gpA inhibited secretion, suggesting that functional activity resides in the protein moiety of gpA . These results suggest that gpA is a specific trigger for abnormalities of surfactant lipids in PCP . This is a unique role for a microbial product in disease pathogenesis and a potentially exploitable therapeutic target.

Trends Biotechnol, 1997 Dec, 15(12), 523 - 30
Directed evolution of enzyme catalysts; Kuchner O et al.; Directed enzyme evolution has emerged in the past few years as a powerful alternative to rational approaches for engineering biocatalysts . Prerequisites for successful directed evolution are functional expression in a suitable microbial host, a rapid screen for the desired feature(s) and a well-thought-out working strategy for navigating protein landscapes . The rapidly growing body of literature on enzyme evolution in vitro includes techniques for creating and searching combinatorial enzyme libraries, as well as several successful examples of different evolutionary strategies being used.

J Exp Med, 1997 Dec 1, 186(11), 1819 - 29
In vivo microbial stimulation induces rapid CD40 ligand-independent production of interleukin 12 by dendritic cells and their redistribution to T cell areas; Reis e Sousa C et al.; The early induction of interleukin (IL)-12 is a critical event in determining the development of both innate resistance and adaptive immunity to many intracellular pathogens . Previous in vitro studies have suggested that the macrophage (MPhi) is a major source of the initial IL-12 produced upon microbial stimulation and that this response promotes the differentiation of protective T helper cell 1 (Th1) CD4+ lymphocytes from precursors that are primed on antigen-bearing dendritic cells (DC) . Here, we demonstrate by immunolocalization experiments and flow cytometric analysis that, contrary to expectation, DC and not MPhi are the initial cells to synthesize IL-12 in the spleens of mice exposed in vivo to an extract of Toxoplasma gondii or to lipopolysaccharide, two well characterized microbial stimulants of the cytokine . Importantly, this production of IL-12 occurs very rapidly and is independent of interferon gamma priming or of signals from T cells, such as CD40 ligand . IL-12 production by splenic DC is accompanied by an increase in number of DCs, as well as a redistribution to the T cell areas and the acquisition of markers characteristic of interdigitating dendritic cells . The capacity of splenic DC but not MPhi to synthesize de novo high levels of IL-12 within hours of exposure to microbial products in vivo, as well as the ability of the same stimuli to induce migration of DC to the T cell areas, argues that DC function simultaneously as both antigen-presenting cells and IL-12 producing accessory cells in the initiation of cell-mediated immunity to intracellular pathogens . This model avoids the need to invoke a three-cell interaction for Th1 differentiation and points to the DC as both a sentinel for innate recognition and the dictator of class selection in the subsequent adaptive response.

Plant Physiol, 1997 Dec, 115(4), 1619 - 27
Identification and characterization of a novel arabinoxylanase from wheat flour; Cleemput G et al.; An endogenous wheat (Triticum aestivum) flour endoxylanase was purified to homogeneity from a crude wheat flour extract by ammonium sulfate precipitation and cation-exchange chromatography . The 30-kD protein had an isoelectric point of 9.3 or higher . A sequence of 19 amino acids at the NH2 terminus showed 84.2% identity with an internal sequence of 15-kD grain-softness protein, friabilin . High-performance anion-exchange chromatography and gel-permeation analysis of the hydrolysis products indicated the preferential hydrolysis of highly branched structures by the enzyme; wheat arabinoxylan and rye (Secale cereale) arabinoxylan (high arabinose to xylose ratios) were hydrolyzed more efficiently by this enzyme than oat (Avena sativa) spelt xylan (low arabinose to xylose ratios) . The release of the hydrolysis products as a function of time suggested that the endoxylanolytic activity was associated with the release of arabinose units from the polysaccharides, suggesting that the enzyme action is similar to that by endoxylanases from Ceratocystis paradoxa, Aspergillus niger, and Neurospora crassa . Although the enzyme released arabinose from arabinoxylan, it did not hydrolyze p-nitrophenyl-alpha-L-arabinofuranoside . From the above, it follows that the enzyme, called arabinoxylanase, differs from most microbial endoxylanases and from an endoxylanase purified earlier from wheat flour.

Clin Chest Med, 1997 Dec, 18(4), 695 - 706
Etiology of sarcoidosis; Moller DR; Since sarcoidosis was first recognized as a distinct clinical entity, investigators have speculated that a transmissible agent may cause sarcoidosis . Recent attempts at directly isolating infectious organisms or indirectly detecting microbial DNA or RNA from sarcoid tissue have led to inconclusive results . Studies on the immunopathogenic origins of sarcoidosis have provided evidence of persistent antigenic stimulation at sites of inflammation that are associated with dysregulated cytokine production . To date, however, the challenge of defining the cause of sarcoidosis remains unmet.

Semin Liver Dis, 1997, 17(4), 297 - 310
Complement and complement deficiencies; Whaley K et al.; The complement system provides a first line of defense and mediates a large variety of cellular and humoral interactions within the immune response, including chemotaxis, phagocytosis, cell adhesion, and B-cell differentiation . The system involves more than 30 serum components and numerous cell surface regulators and receptors . Similar to the blood clotting system, complement activation is initiated through a series of complex activation cascades involving enzymatic cleavage . Three independent complement activation cascades, the classical, the alternative, and the lectin pathway, have been described . The liver is the main site of biosynthesis for most of the serum components of complement and diseases of the liver can lead to alterations of the normally stable plasma levels of complement . Deficiencies of single components can lead to a broad variety of secondary diseases, caused by either imbalanced activation or defects in the humoral or cellular response to microbial infections.

J Capillary Electrophor, 1996 Jul-Aug, 3(4), 209 - 13
Capillary electrophoretic separation of TNT and its transformation products; Pucik L et al.; 2,4,6-Trinitrotoluene (TNT), 2-aminodinitrotoluene (2ADNT), 4-aminodinitrotoluene (4ADNT), and diamino-6-nitrotoluene (DA6NT) in a variety of matrices (including chemical, microbial, and plant extract) were successfully separated and quantified using micellar electrokinetic capillary electrophoresis (MEKC) . The method used a buffer solution of 20 mM in borax, 50 mM in sodium dodecyl sulfate (SDS), and of pH 8.5 . Voltage applied across the capillary was 20 kV and temperature was maintained at 25 degrees C . Compounds eluted within approximately 6-11 min and were identified by both their migration times and spectra.

Ophthalmology, 1997 Nov, 104(11), 1902 - 9
Ofloxacin monotherapy for the primary treatment of microbial keratitis: a double-masked, randomized, controlled trial with conventional dual therapy . The Ofloxacin Study Group; Crystal structure of methyl-coenzyme M reductase: the key enzyme of biological methane formation; Max-Planck-Institut fur Biophysik, Heinrich-Hoffmann-Strabetae 7, 60528 Frankfurt, GermanyMethyl-coenzyme M reductase (MCR), the enzyme responsible for the microbial formation of methane, is a 300-kilodalton protein organized as a hexamer in an alpha2beta2gamma2 arrangement . The crystal structure of the enzyme from Methanobacterium thermoautotrophicum, determined at 1.45 angstrom resolution for the inactive enzyme state MCRox1-silent, reveals that two molecules of the nickel porphinoid coenzyme F430 are embedded between the subunits alpha, alpha', beta, and gamma and alpha', alpha, beta', and gamma', forming two identical active sites . Each site is accessible for the substrate methyl-coenzyme M through a narrow channel locked after binding of the second substrate coenzyme B . Together with a second structurally characterized enzyme state (MCRsilent) containing the heterodisulfide of coenzymes M and B, a reaction mechanism is proposed that uses a radical intermediate and a nickel organic compound.

Appl Environ Microbiol, 1997 Dec, 63(12), 4645 - 50
Frequency of formation of chimeric molecules as a consequence of PCR coamplification of 16S rRNA genes from mixed bacterial genomes; Wang GC et al.; PCR is routinely used in amplification and cloning of rRNA genes from environmental DNA samples for studies of microbial community structure and identification of novel organisms . There have been concerns about generation of chimeric sequences as a consequence of PCR coamplification of highly conserved genes, because such sequences may lead to reports of nonexistent organisms . To quantify the frequency of chimeric molecule formation, mixed genomic DNAs from eight actinomycete species whose 16S rRNA sequences had been determined were used for PCR coamplification of 16S rRNA genes . A large number of cloned 16S ribosomal DNAs were examined by sequence analysis, and chimeric molecules were identified by multiple-sequence alignment with reference species . Here, we report that the level of occurrence of chimeric sequences after 30 cycles of PCR amplification was 32% . We also show that PCR-induced chimeras were formed between different rRNA gene copies from the same organism . Because of the wide use of PCR for direct isolation of 16S rRNA sequences from environmental DNA to assess microbial diversity, the extent of chimeric molecule formation deserves serious attention.

J Dairy Sci, 1997 Nov, 80(11), 2901 - 6
Substitution of neutral detergent fiber from forage with neutral detergent fiber from by-products in the diets of lactating cows; Zhu JS et al.; Four lactating dairy cows that were ruminally and duodenally cannulated were used in an experiment with a 4 x 4 Latin square design to determine the effects of the substitution of neutral detergent fiber (NDF) from forage with NDF from wheat middlings, corn gluten feed, or a blend of distillers dried grains and hominy . Dietary crude protein and NDF averaged 18 and 31%, respectively, for the diet with 71.2% of the NDF from forage (control diet) and for diets with 55% of the NDF from forage (by-product diets) . The substitution of NDF from these by-products for forage NDF did not affect dry matter intake (20.1 kg/d) or digestibility of organic matter . Total tract digestibility of acid detergent fiber was lower for cows fed the diet containing a blend of distillers dried grains and hominy than for cows fed the diet containing corn gluten feed . Microbial crude protein synthesis, milk production (23.9 kg/d), and milk fat percentage were similar for all cows, regardless of diet . Cows fed the diets containing wheat middlings or a blend of distillers dried grains and hominy had reduced ruminal pH compared with that of cows fed the diet containing corn gluten feed or the control diet . Diets containing 55% of total NDF from forage with 31% of total NDF from corn gluten feed, wheat middlings, or a blend of distillers dried grains and hominy can supply sufficient effective fiber to maintain normal ruminal function.

Aust Vet J, 1997 Nov, 75(11), 796 - 9
Use of a multifenestrated indwelling lavage system for treatment of septic digital tenosynovitis in cattle; Anderson DE et al.; Septic tenosynovitis was diagnosed in seven cattle on the basis of history, physical examination, radiographs, cytological examination of tendon sheath fluids, and microbial culture . A commercially available indwelling multifenestrated silicone rubber drain was used to perform frequent lavage of the flexor tendon sheaths . The sepsis resolved in all cattle . Five of six cattle for which long-term (> 1 year) follow-up information was available were clinically sound on the affected limb and had remained productive members of the herd.

Anaesthesia, 1997 Nov, 52(11), 1073 - 6
Convection warmers--not just hot air; Avidan MS et al.; We sought to determine whether the forced air convection warmers (nine Bair Huggers, Augustine Medical, and one Warm Touch, Mallinkrodt Medical) used in our operating theatres could be a source of microbial pathogens . Agar plates were placed directly in the air stream of the warmers . Four of these grew potentially pathogenic organisms . When the warmers were set to blow through perforated blankets, no growth occurred . Three of the warmers were swabbed and sites of colonisation were found in their hoses . After fixing a microbial filter to the end of the hose, organisms were no longer detectable . We conclude that these warming devices are a potential source of nosocomial infection . They should only be used in conjunction with perforated blankets, should have their microbial filters changed regularly and their hoses sterilised . The inclusion of a microbial filter into the nozzle of the hose could be incorporated into the design of the warmer.

J Periodontal Res, 1997 Oct, 32(7), 608 - 13
Polyclonal B cell activators and in vitro induction of auto-antibody reactive with collagen; Hahn CL et al.; Cells producing autoantibodies are known to be present in chronically inflamed periodontal tissues . In sites of chronic inflammation, polyclonal B cell activators (PBA) are known to exhibit adjuvant activity when combined with foreign antigens . These results prompted an examination of PBA in eliciting an antibody response to an autoantigen (i.e . collagen type I) . Rat lymphocytes were stimulated with rat collagen (type I), microbial PBA (LPS) or the combination of LPS plus rat collagen in vitro . Anti-collagen antibody-forming cells (AFC) were enumerated using an ELISPOT assay . Collagen or LPS alone elicited few anti-collagen AFC but the addition of LPS to collagen resulted in a substantial adjuvant effect and yielded maximal responses to collagen . Comparisons of anti-collagen AFC from short-term immunized (2-6 wk after booster), non-immunized and long-term immunized (3-4 months after booster) animals were performed . It revealed that cells from recently immunized rats were significantly easier to activate than the other 2 groups . The adjuvant effect of microbial PBA may be important in anti-collagen antibody production and thus the localization of PBA in periodontal pockets may explain why anti-collagen AFC are restricted to the chronically inflamed periodontal tissues.

J Leukoc Biol, 1997 Dec, 62(6), 693 - 701
Natural killer cells: endothelial interactions, migration, and target cell recognition; Timonen T; Natural killer (NK) cells form a unique third group of lymphocytes that differs from T and B cells in surface phenotype, target recognition, and function . By producing cytokines and exerting cytotoxicity, NK cells participate in the resistance against microbial infections and malignant disease . The research on the molecular mechanisms of migration and target cell recognition by NK cells has recently developed rapidly . NK cells express a number of adhesion molecules common to hematopoietic lineage, bind to endothelium, extravasate, and respond to chemotactic stimuli, much resembling T cells in those respects . However, NK cells are probably capable of transmigration and infiltration merely through activation by cytokines and chemokines, as opposed to the requirement of antigen presentation in the initial activation of T cells . Target cell recognition and ensuing cytotoxicity of NK cells is a sum effect of a delicate balance between the effects of inhibitory and activating NK cell receptors . NK cells express several well-defined MHC I-recognizing receptors that inactivate their functions . In pathological alterations of MHC I expression, the inhibitory receptors do not engage and thus permit the lysis of the target cell . The receptors that trigger the cytolytic machinery of NK cells are less well known . Some candidate triggering receptors have been identified and it seems that NK cell triggering is mediated by multiple receptors, as is the inhibition of cytotoxicity . For example, NK cells clearly detect target cell-bound antibodies and thus mediate antibody-dependent cytotoxicity . They may also detect carbohydrate moieties, normal but pathologically distributed adhesion molecules, as well as ligands for a number of co-stimulatory receptors.

J Biomater Sci Polym Ed, 1997, 8(12), 947 - 61
Rifampicin carrying polyhydroxybutyrate microspheres as a potential chemoembolization agent; Kassab AC et al.; In this study, we attempted to prepare microspheres from a microbial biodegradable polyester, i.e . polyhydroxybutyrate (PHB) as a potential chemoembolization agent . The drug loaded PHB microspheres were prepared by a solvent evaporation technique, in which methylene chloride, distilled water, and polyvinyl alcohol were utilized as the solvent, dispersion medium, and emulsifier, respectively . Microspheres were obtained within a size range of 5-100 microns by changing the initial polymer/solvent ratio, emulsifier concentration, stirring rate, and initial drug concentration . It was possible to obtain PHB with very narrow size distributions by applying gravity field-flow fractionation technique . Very high drug loadings of up to 407.6 mg rifampicin/g PHB were achieved . Drug release rates were very rapid . Almost 90% of the drug loaded was released in about 24 h . Both the size and drug content of PHB microspheres were found to be effective in controlling the drug release from these microspheres.

Am J Kidney Dis, 1997 Dec, 30(6), 859 - 71
National Kidney Foundation report on dialyzer reuse . Task Force on Reuse of Dialyzers, Council on Dialysis, National Kidney Foundation; Mechanisms of action of anti-GM1 and anti-GQ1b ganglioside antibodies in Guillain-Barré syndrome; University Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, United KingdomAnti-GM1 and anti-GQ1b ganglioside antibodies are found in association with acute and chronic peripheral neuropathies, including Guillain-Barre syndrome . They are believed to arise as a result of molecular mimicry with immunogenic microbial polysaccharides . Although anti-ganglioside antibodies are suspected to play a causal role in neuropathy pathogenesis, the details of this have yet to be proven . The approach in this laboratory to solving this issue has been to generate anti-GM1 and anti-GQ1b monoclonal antibodies from peripheral blood lymphocytes of affected patients and to study their immunolocalization in peripheral nerve and their electrophysiologic effects in animal models in which peripheral nerve sites are exposed to anti-ganglioside antibodies . These data show that anti-ganglioside antibody-reactive epitopes are widely distributed in peripheral nerve and can cause electrophysiologic abnormalities in a variety of model systems; thus, these data support the view that anti-ganglioside antibody-reactive epitopes may directly contribute to neuropathy pathogenesis.

JAMA, 1997 Dec 10, 278(22), 1946 - 55
Immunopathogenesis of gastrointestinal and hepatobiliary diseases; Galperin C et al.; The largest lymphoid organ in the body is the gut and the gut-associated lymphoid tissue . The mucosal immune system faces many challenges in protecting the body from microbial invasion . Its chief function is to maintain a diverse population of mature lymphocytes capable of responding to foreign antigens . This task is accomplished with a variety of unique features that distinguish the mucosal from the systemic immune system . In addition, the mucosal immune system plays a role in inflammatory bowel disease, Whipple disease, autoimmune gastritis, Helicobacter pylori infection, immunoproliferative small intestinal disease, hepatitis A, B, C, D, E, F, and G, autoimmune hepatitis, primary biliary cirrhosis, progressive sclerosing cholangitis, and vanishing bile duct syndrome.

Ann Acad Med Singapore, 1997 Jul, 26(4), 395 - 400
Penetrating keratoplasty in the Singapore National Eye Centre and donor cornea acquisition in the Singapore Eye Bank; Chan CM et al.; We analyzed all penetrating keratoplasties performed in the Singapore National Eye Centre from 1 January 1991 to 31 December 1995, using records of the Singapore Eye Bank Registry, evaluating the indications, complications, causes of graft failure, visual outcome and graft survival rate . We also looked into donor cornea acquisition in the Singapore Eye Bank and its influence on the development of corneal transplantation in the Singapore National Eye Centre . A total of 327 penetrating keratoplasties were performed during the 5-year period . Bullous keratopathy was an indication in 26.3% of cases . Of these, aphakic bullous keratopathy accounted for 11.6% of all cases, while pseudophakic bullous keratopathy accounted for 11.3% . Other indications were regrafts (11.9%), corneal dystrophies (10.4%), traumatic corneal scarring (10.1%) and keratoconus (9.8%) . Graft rejection was a complication in 20% of all cases . Of these, 40.9% led to graft failure . Other major complications were raised intraocular pressure (18%), epithelium-related problems (7.3%), wound dehiscence (4.3%), cataract (3.3%) and microbial keratitis (3.1%) . The main causes of graft failure were graft rejection (8.2%), endothelial failure (2.4%), infection (2.4%) and glaucoma (2.1%) . Of the 327 grafts, 40.3% achieved best corrected visual acuity of 6/12 or better; 70.8% achieved vision of 6/24 or better . The overall graft survival rate was 82.3% after a mean follow-up period of 2 years . Donor corneas for the penetrating keratoplasties were obtained from foreign eye banks as well as locally, with the local donation rate steadily increasing from 1991 to 1996, with the establishment of proper eye banking facilities and the Singapore Eye Bank . These results show that the indications and outcome of penetrating keratoplasty in the Singapore National Eye Centre are similar and comparable to that of other centres with established corneal grafting programmes . The establishment of the Singapore Eye Bank has ensured the proper co-ordination of acquisition of donor material which has been vital to the development of corneal transplantation in the Singapore National Eye Centre.

Am J Gastroenterol, 1997 Dec, 92(12 Suppl), 5S - 11S
Pathogenesis and immune mechanisms of chronic inflammatory bowel diseases; Sartor RB; The inflammatory bowel diseases (IBDs) are characterized by intestinal inflammation of unknown etiology . Two distinct disorders, Crohn's disease and ulcerative colitis, have been identified . Three theories of IBD etiology are currently under consideration: 1) reaction to a persistent intestinal infection, 2) existence of a defective mucosal barrier to luminal antigens, and 3) a dysregulated host immune response to ubiquitous antigens . In each of these theories, either pathogenic or resident luminal bacteria constantly stimulate the mucosal and systemic immune systems to perpetuate the inflammatory cascade . Chronicity of inflammation results from an interaction of the persistent stimulus of microbial antigens with genetically determined host susceptibility factors that determine the individual's immune response or mucosal barrier function . The pathogenesis of IBD involves a series of steps, beginning with the breach of the intestinal mucosal barrier by infectious agents or toxins . The defective barrier exposes lamina propria immune cells to the continual presence of resident luminal bacteria, bacterial products, or dietary antigens, which perpetuates the inflammatory cascade . Many immunoregulatory abnormalities are noted in IBD, including the ratio of proinflammatory to immunosuppressive cytokines, selective activation of T(H) lymphocyte subsets, and abnormalities in epithelial antigen presentation . When activated during the initial inflammatory process, macrophages and T lymphocytes secrete a host of cytokines, which recruit other inflammatory cell types, thereby continuing the process . Tissue injury is the net result of the soluble products of the activated inflammatory cells . Knowledge of the pathogenesis in IBD suggests that the ultimate goals of therapy should be to block the proinflammatory mediators toward the proximal, rather than the distal, end of the cascade, to decrease the constant antigenic drive of luminal bacteria, and to correct the dysregulated immune response.

Eur J Immunol, 1997 Nov, 27(11), 2959 - 64
Hypermutation, diversity and dissemination of human intestinal lamina propria plasma cells; Dunn-Walters DK et al.; In this work we have microdissected lamina propria plasma cells and used polymerase chain reaction and sequencing to investigate immunoglobulin (Ig) gene rearrangements and mutations in human intestine . In addition, specific primers were designed for individual Ig gene rearrangements to analyze the distribution of related B cell and plasma cell clones at different sites along the bowel . Confirming our earlier work, intestinal IgVH genes were highly mutated in plasma cells from older individuals (> 30 years) . IgVH genes were significantly less mutated in samples taken from patients aged 11-30 years, and there were fewer mutations again in samples from young children (< 11 years) . In age-matched specimens the number of mutations was equivalent in the duodenum and colon . Using complementarity-determining region 3 primers to amplify specific Ig gene rearrangements, evidence was also found for the existence of related lamina propria plasma cells along the small bowel and colon, although these were quite scarce . In addition, analysis of the numbers of related clones in a random sampling from discrete areas of lamina propria indicates that the local population is diverse . These results suggest that the highly mutated IgVH genes in adult intestinal plasma cells are a consequence of chronic antigen exposure with age . Duodenal plasma cells are as highly mutated as colonic plasma cells, despite the fact that the upper bowel has no indigenous microbial flora (the stimulus for intestinal plasma cells) . They also show that the plasma cell population is diverse and can be widely disseminated along the bowel.

Eur J Immunol, 1997 Nov, 27(11), 2812 - 21
Control of self-reactive cytotoxic T lymphocytes expressing gamma delta T cell receptors by natural killer inhibitory receptors; Halary F et al.; The majority of peripheral blood gamma delta T cells in human adults expresses T cell receptors (TCR) with identical V regions (V gamma 9 and V delta 2) . These V gamma 9 V delta 2 T cells recognize the major histocompatibility complex (MHC) class I-deficient B cell line Daudi and broadly distributed nonpeptidic antigens present in bacteria and parasites . Here we show that unlike alpha beta or V gamma 9- gamma delta T cells, the majority of V gamma 9V delta 2 T cells harbor natural killer inhibitory receptors (KIR) (mainly CD94/NKG2A heterodimers), which are known to deliver inhibitory signals upon interaction with MHC class I molecules . Within V gamma 9V delta 2 T cells, KIR were mainly expressed by clones exhibiting a strong lytic activity against Daudi cells . In stark contrast, almost all V gamma 9V delta 2 T cell clones devoid of killing activity were KIR-, thus suggesting a coordinate acquisition of KIR and cytotoxic activity within V gamma 9V delta 2 T cells . In functional terms, KIR inhibited lysis of MHC class I-positive tumor B cell lines by V gamma 9V delta 2 cytotoxic T lymphocytes (CTL) and raised their threshold of activation by microbial antigens presented by MHC class I-positive cells . Furthermore, masking KIR or MHC class I molecules revealed a TCR-dependent recognition by V gamma 9V delta 2 CTL of ligands expressed by activated T lymphocytes, including the effector cells themselves . Taken together, these results suggest a general implication of V gamma 9V delta 2 T cells in immune response regulation and a central role of KIR in the control of self-reactive gamma delta CTL.

J Oral Maxillofac Surg, 1997 Dec, 55(12 Suppl 5), 25 - 30
The influence of 0.12% chlorhexidine digluconate rinses on the incidence of infectious complications and implant success; Lambert PM et al.; The effect of perioperative chlorhexidine on the frequency of infectious complications through stage II was examined . Chlorhexidine was used perioperatively in 54.6% of patients (52.5% of implants) in a Dental Implant Clinical Research Group study with a database of 2,641 implants (595 patients) . With chlorhexidine, there was a significant reduction in the number of infectious complications (4.1% vs 8.7%) . Two percent of implants failed in the absence of an infectious complication, whereas 12% with infectious complications failed . This sixfold difference is highly significant . Chlorhexidine may reduce microbial complications when used in the immediate perioperative period.

J Dent Res, 1997 Dec, 76(12), 1854 - 61
Prevalence and depth of artificial caries-like lesions adjacent to cavities prepared in roots and restored with a glass ionomer or a dentin-bonded composite material; Gilmour AS et al.; One potential advantage of glass-ionomer materials for the treatment of root caries is their ability to release fluoride and so resist cariogenic attack . A commercially available composite material has also been reported to release fluoride which reduced caries lesions in the tooth tissue adjacent to it . The aim of this study was to assess the effectiveness of a conventional glass-ionomer restoration compared with a dentin-bonded, fluoride-releasing, composite restoration when exposed to a microbial artificial caries system . Artificial caries-like lesions produced in relation to the restorations were examined and classified either as outer (surface) lesions or as wall lesions . A split-unit experimental design allowed for within-tooth comparisons of the 2 experimental restorations at different sites on the root surface . These were either totally within the root surface or positioned at the amelo-cemental junction . Outer lesion depths were significantly (p < 0.001) shallower at all sites adjacent to the glass ionomer when compared with the composite restorations . Wall lesions were significantly (p < 0.01) more prevalent adjacent to the composite material . In addition, the cavity margin position significantly (p < 0.05) affected the incidence of wall lesions, particularly in the composite group . In conclusion, glass ionomer was successful in reducing the caries-like lesion production in the adjacent root surface . This resulted from improved marginal integrity and fluoride release from this material when compared with the composite bonding system used.

J Dent Res, 1997 Dec, 76(12), 1833 - 9
Profile of cytokine mRNA expression in chronic adult periodontitis; Roberts FA et al.; Chronic inflammation induced by bacteria often leads to host-mediated destruction of tissues adjacent to the sites of microbial insult . The chronic inflammatory process of adult periodontitis results in the destruction of supporting osseous and connective tissues of the teeth . We hypothesized that virulence factors of periodontal pathogens such as lipopolysaccharide stimulate inflammatory cytokine expression by mononuclear cells of the host which contribute to disease development . In this study, to elucidate the role of these cytokines in chronic adult periodontitis, we tested whether the prevalence of mRNA for inflammatory cytokines generally associated with mononuclear phagocytes was higher in diseased than in healthy gingival tissue . Gingival mononuclear cells or whole gingival biopsies from 32 adult periodontitis patients and five healthy individuals used as controls were evaluated for inflammatory cytokine mRNA expression by reverse-transcription polymerase chain-reaction (RT-PCR) procedures . The cytokines assessed included IL-1 alpha, IL-1 beta, IL-1ra, IL-6, IL-8, IL-12, IL-13, TNF-alpha, TGF-beta, and IFN-gamma . The monocyte/macrophage lipopolysaccharide (LPS) receptor CD14 was also assessed . Results showed that TNF-alpha mRNA was present significantly more frequently in diseased than in healthy biopsies, whereas IL-1 alpha, IL-1 beta, and IL-1ra mRNA were found in most (from 80 to 100%) healthy tissues . Message for CD14 was present in both healthy and diseased tissue samples (100%) . This study provides evidence for a major role of TNF-alpha in chronic adult periodontitis . Moreover, our results suggest that the mononuclear cells derived from periodontal tissues have the capacity to respond to components of periodontal pathogens and express both pro- and anti-inflammatory cytokines in these tissues.

Plant Physiol, 1997 Nov, 115(3), 949 - 57
Starches from A to C . Chlamydomonas reinhardtii as a model microbial system to investigate the biosynthesis of the plant amylopectin crystal; Buleon A et al.; Wide-angle powder x-ray diffraction analysis was carried out on starch extracted from wild-type and mutant Chlamydomonas reinhardtii cells . Strains containing no defective starch synthases as well as mutants carrying a disrupted granule-bound starch synthase structural gene displayed the A type of diffraction pattern with a high degree of crystallinity . Mutants carrying a defect for the major soluble starch synthase (SSS), SSS II, were characterized by a switch to the B type of diffraction pattern with very low crystallinity . Mutant strains carrying SSS I as the only glucan elongation enzyme regained some of their crystallinity but switched to the C type of diffraction pattern . Differential scanning calorimetry analysis correlated tightly with the x-ray diffraction results . Together with the electron microscopy analyses, these results establish C . reinhardtii as a microbial model system displaying all aspects of cereal starch synthesis and structure . We further show that SSS II is the major enzyme involved in the synthesis of crystalline structures in starch and demonstrate that SSS I alone builds a new type of amylopectin structure.

J Anim Sci, 1997 Nov, 75(11), 2986 - 93
Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3; Biehl RR et al.; Commercial and laboratory-strain crossbred chicks responded (P < .01) markedly to 1alpha-hydroxycholecalciferol (1alpha-OH D3) during the 2nd and 3rd wk of life . Bone-ash responses exceeded 50% when this compound was added at 20 microg/kg to phosphorus (P)-deficient corn-soybean meal diets containing surfeit levels (25 microg/kg) of cholecalciferol (D3) . Phosphorus excretion was decreased (P < .01) and, thus, retention was increased (P < .01) when 1alpha-OH D3 was supplemented . A P-deficient (.10% P) casein-amino acid purified diet, devoid of D3, was used to determine whether 15 microg/kg of D3 was sufficient to facilitate optimal absorption of the nonphytate P contained in this diet . Bone ash responded to .075% P addition (KH2PO4), and chicks fed diets with .175% nonphytate P exhibited further bone-ash responses to 15 microg/kg of D3 or 10 microg/kg 1alpha-OH D3 . Higher levels of either of these D3 compounds did not produce additional responses . This suggested that 15 to 25 microg/kg of D3 in a P-deficient corn-soybean meal diet (.28% phytate P and .14% nonphytate P) is more than adequate to facilitate optimal absorption of the nonphytate P present in the diet . A P-deficient casein-dextrose diet (.13% nonphytate P and 15 microg/kg D3) was fed in the final chick assay, and chicks fed this diet did not show bone ash responses to 1alpha-OH D3 or to microbial-derived phytase (1,470 units/kg) . Thus, with P-deficient corn-soybean meal diets containing at least 15 microg D3/kg, 1alpha-OH D3 supplementation markedly increased weight gain and bone ash because it increased the utilization of phytate P.

Acta Ophthalmol Scand, 1997 Aug, 75(4), 418 - 22
Graft survival and risk factors of penetrating keratoplasty for microbial keratitis; Lomholt JA et al.; PURPOSE: To evaluate graft survival rates and prognostic factors in relation to penetrating keratoplasty for microbial keratitis . METHODS: The records of 95 patients treated with penetrating keratoplasty for microbial keratitis during a twenty-year period were reviewed . Data were analysed by construction of survival curves using the Kaplan-Meier non parametric method . RESULTS: The overall survival of a clear cornea was 72% after one year, 71% after two years and 52% after five years . A significantly lower survival rate (p<0.05) was found in the presence of preoperative local risk factors such as wear of contact lenses and trauma and in inflamed eyes . In contrast, systemic diseases like diabetes, cancer or rheumatoid arthritis did not affect survival and neither did recipient age nor the degree of vascularization of the eye . Male donor buttons showed superior survival compared to female ones (p < 0.05), while females seemed to constitute the best recipients . Recurrence rates of microbial keratitis postoperatively were 11%, 16% and 24% after one, two and five years, respectively . Corresponding graft rejection rates were 9%, 15% and 27% . CONCLUSIONS: Patients suffering from microbial keratitis have a relatively high risk of graft failure . To improve the prognosis care should be taken to minimize local risk factors . Surgery should whenever possible be performed on quiet eyes . The unexpected finding of a better prognosis for male donor buttons might suggest the preferred use of male donors in patients suffering from microbial keratitis, but the observation needs further documentation.

Immunotechnology, 1995 Dec, 1(3-4), 211 - 9
Induction of mucosal anti-HIV antibodies by facilitated transfection of airway epithelium with lipospermine/DNA complexes; Mitchell WM et al.; BACKGROUND: Expression of microbial protein sequences in eukaryotic cells transfected by transcriptional/translational permissive cDNA constructs can induce systemic humoral and cellular responses in vivo . Two methods of in vivo transfection have been described to date . One method uses large quantities of naked DNA injected into skeletal muscle . The second method uses relatively small quantities of DNA complexed to gold particles for bollistic penetration of the plasma membrane of keratinocytes . The major disadvantage of the bolistic method is that instrumentation is required which is not generally available . OBJECTIVES: The objectives of this study were to determine whether the use of DNA complexed with a cationic lipopolyamine could reduce the quantity of DNA required to induce systemic humoral responses following muscle transfection and whether similar DNA/lipopolyamine complexes could induce mucosal humoral responses following airway exposure . STUDY DESIGN: Balb/c mice were exposed by nasal aerosol or intramuscular inoculation to a mammalian transcriptional/translational permissive DNA construct containing the entire sequence for the HIV-1 envelope polyprotein . Experimental animals were further segregated by the number of exposures at 3-week intervals and whether the DNA was complexed to dioctadecylamidoglycylspermine (DOGS) at a 5:1 molar charge ratio of DOGS/DNA . RESULTS: DOGS facilitated in vivo transfection of mouse muscle reduced the quantity of DNA required for a systemic humoral response to surface expressed HIV-envelope proteins by one order of magnitude . Exposure of airway mucosa to both 10 micrograms and 1 microgram quantities of DNA complexed to DOGS produced systemic humoral responses to HIV-envelope as well as mucosal antibodies in pulmonary and colonic epithelia . Molecular modeling of DOGS/DNA complexes at the 5:1 charge ratio used in this study indicates that the DNA component is not exposed to aqueous solvents and may be relatively resistant to degradation under common biological environments . CONCLUSION: Facilitated transfer of DNA by DOGS to transcriptional/translational competent cells offers several distinct advantages to the use of DNA alone . Since significantly smaller amounts of DNA are required, the potential for the induction of antibodies against DNA itself lessens the likelihood for the development of a lupus-like syndrome . More importantly, however, is the apparent ability to transfect mucosal cells which results in the development of specific mucosal immune responses . This procedure may allow the development of general methods for the induction of mucosal immunity at the level of entry for mucosal pathogens without the disadvantages inherent in live attenuated vectors.

Curr Opin Hematol, 1994 Nov, 1(6), 443 - 51
Leukocyte depletion of cellular blood components; Lane TA; Clinical studies have indicated that the use of leukocyte-reduced cellular blood components produced in the laboratory may prevent febrile reactions and delay or prevent alloimmunization to HLA antigens and refractoriness to platelet transfusion . Additional investigations regarding the effects of the use of leukocyte-reduced blood components were reported during the past year . A recent study in patients with hematologic malignancy that employed the commonly used bedside leukocyte-reduction filters failed to confirm a decrease in the rate of alloimmunization, except in a subgroup of patients with acute myelogenous leukemia . Another major multicenter trial confirmed the effectiveness of leukocyte-reduced blood components in the prevention of cytomegalovirus infection . The effect of allogeneic leukocytes in transfused blood on immune function in patients undergoing colorectal surgery continues to receive attention . Whereas one study failed to demonstrate an adverse effect of standard blood components on disease recurrence or survival, a second study demonstrated a marginally significant decrease in infectious complications in patients who received only leukocyte-reduced blood . Increasingly efficient leukocyte-reduction filters have been developed for cellular blood components, many of which are best suited for laboratory filtration of unstored blood . Laboratory studies indicate that prestorage leukocyte-reduction of cellular blood components does not impair erythrocyte or platelet function and will not increase the incidence of microbial contamination of blood . New methods that employ flow cytometry should enable improved quality control of blood components rendered leukocyte-reduced by the newer, more efficient filters . Finally, a cost-benefit analysis suggests that the appropriate use of leukocyte-reduction filters for acute leukemia patients may reduce the cost of health care to these patients.

FEBS Lett, 1997 Oct 20, 416(2), 139 - 42
An estrogen inducible 104 kDa chaperone glycoprotein binds ferric iron containing proteins: a possible role in intracellular iron trafficking; Poola I; We have previously described an estrogen inducible, intracellular, homodimeric membrane glycoprotein (subunit Mr 104 kDa) which is structurally related to 'chaperone' proteins (Poola, I . and Kiang J.G., J . Biol . Chem . 269 (1994) 21762-21769) . In this report we describe a novel finding that the 104 kDa chaperone protein exhibits affinity for iron containing proteins such as transferrins from several species, human lactoferrin and microbial ferric binding protein (FBP) . A single ferric ion in the above proteins appears to be sufficient for binding . It also binds to immobilized ferritin . However, it does not exhibit any affinity for apotransferrins, apolactoferrin, apoferritin and apoFBP . This is the first report of a chaperone protein that exhibits affinity for iron containing proteins.

Emerg Infect Dis, 1997 Oct-Dec, 3(4), 551 - 4
Strategies for rapid response to emerging foodborne microbial hazards; Majkowski J; The foodborne outbreak paradigm has shifted . In the past, an outbreak affected a small local population, had a high attack rate, and involved locally prepared food products with limited distribution . Now outbreaks involve larger populations and may be multistate and even international; in many the pathogenic organism has a low infective dose and sometimes is never isolated from the food product . Delay in identifying the causative agent can allow the outbreak to spread, increasing the number of cases . Emergency intervention should be aimed at controlling the outbreak, stopping exposure, and perhaps more importantly, preventing future outbreaks . Using epidemiologic data and investigative techniques may be the answer . Even with clear statistical associations to a contaminated food, one must ensure that the implicated organism could logically and biologically have been responsible for the outbreak.

Eur J Immunol, 1997 Oct, 27(10), 2666 - 72
Secreted proteophosphoglycan of Leishmania mexicana amastigotes activates complement by triggering the mannan binding lectin pathway; Peters C et al.; Cutaneous lesions induced by infection of mice with the protozoan parasite, Leishmania mexicana, contain abundant amounts of a high molecular mass proteophosphoglycan (PPG), which is secreted by the amastigote stage residing in phagolysosomes of macrophages and can then be released into the tissue upon rupture of the infected cells . Amastigote PPG forms sausage-shaped but soluble particles and belongs to a novel class of serine-rich proteins that are extensively O-glycosylated by phosphooligosaccharides capped by mannooligosaccharides . The purified molecule is shown here to efficiently activate complement (C) and deplete hemolytic activity of normal serum and may prevent the opsonization of L . mexicana amastigotes . Complement activation is Ca2+ dependent but does not depend on antibodies or the complement component C1 . PPG binds to serum mannan binding protein (MBP), thus activating the MBP-associated serine protease, P100 . Subsequently, the C cascade is triggered through C4 leading to covalent modification probably of carbohydrate hydroxyls of PPG by C3 fragments . Thus, PPG is able to activate C via the mannan binding lectin pathway which is unusual for secreted, soluble products of microbial origin . The proteophosphoglycan-induced complement activation is postulated to contribute to the lesion development and pathology caused by the parasite.

Emerg Infect Dis, 1997 Oct-Dec, 3(4), 417 - 23
Infectious disease as an evolutionary paradigm; Lederberg J; The basic principles of genetics and evolution apply equally to human hosts and to emerging infections, in which foodborne outbreaks play an important and growing role . However, we are dealing with a very complicated coevolutionary process in which infectious agent outcomes range from mutual annihilation to mutual integration and resynthesis of a new species . In our race against microbial evolution, new molecular biology tools will help us study the past; education and a global public health perspective will help us deal better with the future.

Chirality, 1997, 9(7), 667 - 71
Chirality of the gamma-lactones produced by Sporidiobolus salmonicolor grown in two different media; Dufosse L et al.; Sporidiobolus salmonicolor is an aroma-producing yeast which gives a peach-like smell to the culture media . The enantiomeric ratios of the five gamma-lactones produced by this yeast cultivated in two different media were determined by multidimensional gas chromatography (MDGC) on a fused silica capillary column coupled to a modified beta-cyclodextrin column . These ratios remain constant during growth and are not affected by the composition of the medium . The (R)-enantiomer is highly predominant (99%) for gamma-decalactone and predominant (68-88%) for gamma-octalactone, gamma-nonalactone, and (Z6)-gamma-dodecenolactone . A ratio close to racemic was found for gamma-dodecalactone . A discussion on the metabolic origin of these lactones is based on the analysis of the enantiomeric ratios obtained . With respect to consumers' preference for products considered as "natural," microbial lactone production may represent a valuable alternative to fruit flavors . The enantiomeric lactone ratios produced by Sporidiobolus salmonicolor are compared with those reported from some fruits.

AIDS, 1997 Nov, 11(13), 1575 - 81
HIV-1 detection in cervicovaginal secretions during pregnancy; Loussert-Ajaka I et al.; OBJECTIVE: To assess the reproducibility of and factors associated with HIV detection in cervicovaginal secretions (CVS) . DESIGN: Longitudinal study of 43 HIV-1-infected pregnant women in Paris . METHODS: HIV DNA was detected in peripheral blood mononuclear cells (PBMC) by Amplicor and gag nested polymerase chain reaction (PCR) assays . The HIV genotype was determined by heteroduplex mobility assay . Amplicor and gag nested PCR assays were performed on serial CVS samples for HIV DNA detection, and the HIV Monitor test was used for HIV RNA detection in plasma and CVS . RESULTS: A total of 144 CVS samples were collected from the women included in the study . HIV-1 DNA was detected in 36 (25%) of the 144 samples, from 16 (37.2%) of the 43 women . Results of HIV-1 DNA detection were concordant in the first two samples in 27 (84.4%) of the 32 women with at least two CVS samples . The last CVS sample collected in each woman was HIV-1 DNA-positive in 13 (30.2%) of the 43 women . Three factors were found to be independently associated with HIV-1 DNA detection in CVS: HIV-1 subtype B, absence of zidovudine therapy, and microbial cervicovaginal infection . HIV RNA was detected in CVS from 10 (23.3%) out of 43 women and correlated with DNA detection in the same sample and HIV RNA detection in plasma . CONCLUSIONS: DNA and RNA PCR can be used to detect HIV in cells and supernatants of CVS . These techniques may be useful in cohort studies to investigate HIV transmission and to evaluate the efficacy of antiretroviral drugs to reduce HIV excretion.

J Biol Chem, 1997 Nov 14, 272(46), 28933 - 8
Functional complementation of the yeast divalent cation transporter family SMF by NRAMP2, a member of the mammalian natural resistance-associated macrophage protein family; Pinner E et al.; The mammalian NRAMP gene family has two members, NRAMP1 and NRAMP2 that encode integral membrane proteins . Nramp1 is expressed exclusively in macrophages where it is found in the phagosomal membrane, and NRAMP1 mutations cause susceptibility to infection by abrogating the capacity of macrophages to control intracellular microbial replication . Nramp2 is highly similar to Nramp1, but is expressed in several tissues and cell types . The Nramp protein family is remarkably conserved throughout evolution, and recent data suggest that the mammalian Nramp2 and the yeast homologues Smf1 and Smf2 transport divalent cations . We tested whether structural similarity between the mammalian Nramp and the yeast Smf proteins results in functional complementation in yeast . Wild-type and mutant variants of the Nramp1 and Nramp2 proteins were expressed in a yeast mutant bearing null alleles at the SMF1 and SMF2 loci, and complementation of the phenotypes of this yeast mutant was investigated . Nramp2, but not Nramp1, was found to complement hypersensitivity to EGTA of the smf1/smf2 mutant under oxidative stress conditions (methyl viologen) . We also observed that the smf1/smf2 double mutant is hypersensitive to growth at alkaline pH (pH 7.9) and that Nramp2 could complement this phenotype as well . Complementation by Nramp2 was specific and required a functional protein as independent mutations in residues highly conserved in all members of the Nramp family abrogated Nramp2 complementation . Since Mn2+ was the only divalent cation capable of completely suppressing both the EGTA and pH phenotypes, our results suggest that Nramp2 can transport Mn2+ in yeast.

Life Sci, 1997, 61(18), 1843 - 50
Nicotinamide inhibits inducible nitric oxide synthase enzyme activity in macrophages by allowing nitric oxide to inhibit its own formation; Andrade J et al.; Nitric oxide (NO) production by macrophages is mainly regulated by induction of nitric oxide synthase (iNOS) by cytokines and microbial products . Nicotinamide (NIC) inhibits NO production by activated macrophages in a dose dependent manner . NIC also inhibits NOS enzyme activity in extracts from activated macrophages . The inhibition was noncompetitive with L-arginine (Ki 13.37 +/- 4.40 mM, n=3), uncompetitive versus NADPH (Ki 3.06 +/- 0.17 mM, n=3) and tetrahydrobiopterin . Finally, the inhibition by nicotinamide was fully reversed by scavenging NO with hemoglobin . We suggest that NIC acts by allowing NO to inhibit its own formation.

J Dairy Sci, 1997 Oct, 80(10), 2449 - 53
Nutritional risk factors in the etiology of left displaced abomasum in dairy cows: a review; Shaver RD; The transition period occurring 2 wk prepartum through 2 to 4 wk postpartum is the major risk period in the etiology of left displaced abomasum . The prepartum depression of intake and the slow postpartum increase in intake are risk factors causing lower ruminal fill, reduced forage to concentrate ratio, and increased incidence of other postpartum disorders . Uncomplicated ketosis, retained placenta, metritis, and hypocalcemia at parturition are risk factors for left displaced abomasum . Excessive amounts of concentrate during the prepartum period increase the risk of left displaced abomasum, which may occur from the lower ruminal fill caused by greater prepartum intake depression and reduced forage to concentrate ratio, decreased ruminal motility from lower ruminal fill and higher volatile fatty acid concentration, and decreased abomasal motility and emptying from higher concentrations of volatile fatty acids . Effects of volatile fatty acids on motility may be exacerbated by low ruminal absorption of volatile fatty acids during the transition period . Minimal intake of concentrate during the prepartum period may increase the risk of left displaced abomasum through failure to increase the absorptive capacity of the ruminal papillae and failure of the microbial population of the rumen to adapt prior to the intake of high energy postpartum diets . Increased risk of left displaced abomasum in cows that are hypocalcemic at parturition may be due to decreased ruminal and abomasal motility.

Nat Med, 1997 Nov, 3(11), 1266 - 70
A novel protein that participates in nonself discrimination of malignant cells by homologous complement; Matsumoto M et al.; The human complement (C) system protects an individual against substances of nonself origin, including xenografts and microbial pathogens . Human cells express C-regulatory proteins, CD46 and CD55, thereby circumventing attack by C3, a major effector of C . Nevertheless, certain malignant cells, particularly those undergoing apoptotic stress, can activate homologous C, overcoming the regulatory actions of CD46 and/or CD55 . The molecular mechanisms whereby malignant cells are tagged by homologous C3 remain largely unknown . We identified a novel gene product that converts human cells into targets for homologous complement . Only malignant cells and cell lines exposed to Fas or X-irradiation stimuli produced this protein, designated M161Ag, which was an unglycosylated 43-kDa protein . Analysis of cloned cDNAs indicated that this molecule was a secretory protein containing five amino acids encoded by TGA codons . Its functions were unique in that once secreted from the tumor cells, it bound back to the surface of these cells and activated homologous complement (C3) via the alternative pathway, allowing for C3 deposition on the membrane . This molecule may offer new insight into innate immunity; surveillance of tumor cells by complement is a common feature in the human immune system.

J Nat Prod, 1997 Oct, 60(10), 959 - 66
Isolation, structure elucidation, and biological activity of the steroid oligoglycosides and polyhydroxysteroids from the Antarctic starfish Acodontaster conspicuus; De Marino S et al.; A total of 19 steroids, of which 13 steroidal oligoglycosides (nine new and four known) and six polyhydroxylated steroids (four new and two known), has been isolated from the Antarctic starfish Acodontaster conspicuus . The mixture is dominated by glycosides composed of steroidal aglycons having the hydroxyl groups typically disposed on one side of the tetracyclic nucleus, i.e., 3 beta,4 beta,6 alpha,8,15 beta-, with some having a sulfate at C-6, and differing in the side chains and/or in the disaccharide moieties that are usually attached at C-26, with some at C-28 and C-29 . Those compounds are accompanied by minute amounts of glycosides with a delta 8(14)-double bond in the steroid, which is a structural feature not previously found among polyhydroxysteroids derived from starfish . Small amounts of six related unglycosidated polyhydroxysteroids and three higher-molecular-weight asterosaponins complete the composition of the mixture . The structures of the new compounds were determined by interpretation of their spectral data and by comparison with spectral data of known compounds . Eighteen of these compounds were evaluated for their ability to inhibit growth in Antarctic marine bacteria isolated from either the water column or the surfaces of benthic marine invertebrates . Of these compounds, 50% were active against at least one Antarctic marine bacterium . This suggests that these compounds may play an important role in deterring microbial fouling.

PDA J Pharm Sci Technol, 1997 Sep-Oct, 51(5), 203 - 7
Pharmaceutical container/closure integrity . III: Validation of the helium leak rate method for rigid pharmaceutical containers; Kirsch LE et al.; Validation of a helium leak rate method for pharmaceutical container/closure integrity quality assurance required the demonstration that this physical testing method was as good or better than microbial immersion challenge testing in detecting potential integrity failures . One lot of rubber-stoppered, broth-filled glass vials also containing defective vials with known leaks were subjected to both helium leak rate and microbial challenge testing . The defective vials were prepared by affixing glass micropipettes (0.1 to 10 microns) into the vial side walls . The validation lot included a 10% seeded defect rate of which about 50% contained leaks with a predicted probability of failing a microbial challenge (> 10%) . Helium tracer was placed in the test units by charging them for 4 hours under a 40 psi helium pressure . The critical leak rate after charging was determined to be 10(-7) standard cc/second, and test units with measured leak rates greater than this value were considered helium leak rate failures . Microbial immersion challenge was conducted by exposing the test units in a bath inoculated with 10(9-10) viable E . coli and B . diminuta organisms for 24 hours followed by a 13 day (35 degrees C) incubation . Microbial failures were determined visually . The helium and microbial leak test methods were compared statistically using mean failure rates . The mean helium failure rate was 6.9%, whereas the mean microbial failure rate was 2.8% . The difference between helium and microbial failure rates was significantly greater than zero . Thus, helium leak rate testing was demonstrated to be a suitable pharmaceutical container/closure integrity method for microbial quality assurance of rigid containers.

PDA J Pharm Sci Technol, 1997 Sep-Oct, 51(5), 195 - 202
Pharmaceutical container/closure integrity . II: The relationship between microbial ingress and helium leak rates in rubber-stoppered glass vials; Kirsch LE et al.; Helium leak rate measurements were quantitatively correlated to the probability of microbial ingress for rubber-stoppered glass vials subjected to immersion challenge . Standard 10-mL tubing glass vials were modified by inserting micropipettes of various sizes (0.1 to 10 microns nominal diameter) into a side wall hole and securing them with epoxy . Butyl rubber closures and aluminum crimps were used to seal the vials . The test units were sealed in a helium-filled glove bag, then the absolute helium leak rates were determined . The test units were disassembled, filled with media, resealed, and autoclaved . The test units were thermally treated to eliminate airlocks within the micropipette lumen and establish a liquid path between microbial challenge media and the test units' contents . Microbial challenge was performed by immersing the test units in a 35 degrees C bath containing magnesium ion and 8 to 10 logs of viable P . diminuta and E . coli for 24 hours . The test units were then incubated at 35 degrees C for an additional 13 days . Microbial ingress was detected by turbidity and plating on blood agar . The elimination of airlocks was confirmed by the presence of magnesium ions in the vial contents by atomic absorption spectrometry . A total of 288 vials were subjected to microbial challenge testing . Those test units whose contents failed to show detectable magnesium ions were eliminated from further analysis . At large leak rates, the probability of microbial ingress approached 100% and at very low leak rates microbial ingress rates were 0% . A dramatic increase in microbial failure occurred in the leak rate region 10(-4.5) to 10(-3) std cc/sec, which roughly corresponded to leak diameters ranging from 0.4 to 2 microns . Below a leak rate of 10(-4.5) std cc/sec the microbial failure rate was < 10% . The critical leak rate in our studies, i.e . the value below which microbial ingress cannot occur because the leak is too small, was observed to be between 10(-5) and 10(-5.8) std cc/sec, which corresponds to an approximate leak diameter of 0.2-0.3 micron.

PDA J Pharm Sci Technol, 1997 Sep-Oct, 51(5), 187 - 94
Pharmaceutical container/closure integrity . I: Mass spectrometry-based helium leak rate detection for rubber-stoppered glass vials; Kirsch LE et al.; The development of mass spectrometry-based leak detection for pharmaceutical container integrity was undertaken to provide an alternative to microbial challenge testing . Standard 10-mL vials were modified to contain pinholes (0.5 to 10 microns) by affixing micropipettes with epoxy into 2-mm vial side wall holes . The absolute leak rate was determined using vials that were sealed in a tracer (helium) environment with butyl rubber stoppers and crimps . Alternatively leak rates were determined using vials that were sealed in room air and exposed to tracer under pressure (charging or bombing) . Tracer leak rates were measured with mass spectrometry leak rate detectors . The absolute leak rate was correlated the squared nominal leak radius which suggested that the mode of gas flow through the glass pipette leaks was more turbulent than viscous even at low leak rates typically associated with viscous flow . The minimum observed absolute leak rate was about 10(-6.6) std cc/sec and was likely due to helium permeation through the rubber stoppers . Heat-stressed rubber stoppers did not affect the baseline absolute leak rate . Adsorption of helium tracer to the test unit surfaces was found to confound baseline leak rate measurement reliability but was eliminated as a source of variation by exposing the test units to ambient air for > or = 12 hours . The absolute leak rate and the leak rate measured after charging were related in a mathematically predictable way.

Poult Sci, 1997 Nov, 76(11), 1535 - 42
The efficacy of phytase in corn-soybean meal-based diets for laying hens; Van der Klis JD et al.; Microbial phytase hydrolyzes poorly degradable vegetable phytate P in the gastrointestinal tract of poultry; thereby increasing the availability of organic P to an extent that remains to be established . For this purpose, the P equivalency value of phytase in corn-soybean meal layer diets was assessed in three experiments (two short-term absorption studies and one performance trial lasting a complete production period) . In the first absorption study, two basal diets containing 30 or 40 g Ca/kg diet were supplemented with either phytase {0, 250, or 500 phytase units (FTU)/kg diet} or with monocalcium phosphate (MCP; 0, 0.5, or 1.0 g P/kg diet) and fed to layers from 20 to 24 wk of age . The ileal absorption of Ca and P was measured during the last week . It was shown that 250 FTU/kg diet hydrolyzed an amount of phytate P that was equivalent to 1.3 g P from MCP . At the highest phytase inclusion level (500 FTU/ kg diet), a lower value of equivalency was observed, as P absorption was almost maximal at the lower level of phytase inclusion (250 FTU/kg diet) . Phytase hydrolyzed phytate-bound P effectively at both Ca levels, although this degradation was significantly reduced by 12 percentage units at the higher dietary Ca level . The second absorption study, used 0, 250, and 500 FTU phytase/kg diet and 0 and 1.0 g P/kg diet of MCP . All diets were standardized at 35 g Ca/kg diet . The ileal absorption of Ca and P was determined at 24 and 36 wk of age . These values were significantly reduced in 36-wk-old hens compared to 24-wk-old hens . At 24 wk of age, phytic acid P degradation was significantly improved with increasing levels of phytase up to the maximum inclusion level of 500 FTU/kg diet (maximum phytic acid-P degradation at the end of the small intestine was 66%) . In this experiment, the dose of 250 FTU/kg diet was equivalent to 0.8 g MCP-P . In Experiment 3, either phytase or MCP-P was added to a corn-soybean meal layer diet, containing 40 g Ca/kg diet and 3.6 g P/kg diet, at levels of 0, 100, 200, and 300 FTU/kg or levels of 0, 0.3, 0.6, and 0.9 g MCP-P/kg, respectively . Production performance was measured from 18 to 68 wk of age . Diets were consumed ad libitum . Growth, production performances (except kilograms of feed per kilogram of egg), and tibia parameters were significantly improved by dietary supplementation of the negative control diet with either phytase or MCP-P . Growth, egg production, and feed conversion ratio of the hens from the supplemented groups remained good throughout the experiment . No phytase dose effects on the production characteristics or tibia parameters were observed, indicating that the P requirements of the laying hens were met throughout the production period even at the lowest level of supplementation.

Curr Microbiol, 1997 Dec, 35(6), 343 - 7
Microbial Degradation of Diphenylamine Under Anoxic Conditions
Drzyzga O, Blotevogel KH.
Diphenylamine (DPA) was cometabolically degraded in anoxic sediment-water batch enrichments and in cultures of newly isolated sulfate-reducing bacteria . In gas chromatography-mass spectrometry (GC-MS) measurements, aniline was identified as a major breakdown product of the diphenylamine structure . After its identification, aniline was quantified by reversed phase high pressure liquid chromatography (HPLC) . The fate of the other carbon ring system remained unclear, because benzene (as a product of reductive cleavage), phenol (as a product of hydrolytic cleavage), and/or other ring cleavage products of diphenylamine were not observed in our experiments with the methods employed.

Nature, 1997 Oct 30, 389(6654), 985 - 90
Polyisoprenyl phosphates in intracellular signalling; Levy BD et al.; In response to environmental stimuli, leukocyte membrane remodelling generates biologically active lipids that can serve as both intra- and extracellular mediators . There are several classes of lipids that can mediate inflammatory reactions . We report here on a new intracellular lipid signal that regulates oxygen-radical formation in neutrophils, a key response in microbial killing, inflammation and tissue injury . Screening of neutrophil-derived extracts rich in phosphorylated, non-saponifiable lipids revealed a potent inhibitor of superoxide anion (O2-) production . Structural analysis of biologically active fractions gave four major phosphorylated lipids: most abundant was presqualene diphosphate (PSDP) . Upon activation of neutrophil receptors, PSDP and its monophosphate form, presqualene monophosphate (PSMP), undergo rapid remodelling . At submicromolar concentrations, PSDP but not PSMP inhibit O2- production by human neutrophil cell-free oxidase preparations . We prepared PSDP and PSMP by total organic synthesis and matched both the physical properties and biological activity of the neutrophil-derived compounds . Our results indicate that PSDP, a recognized intermediate of cholesterol biosynthesis, is present in immune effector cells and is a potent regulator of the cellular response in host defence.

Infect Immun, 1997 Nov, 65(11), 4858 - 64
Helicobacter bilis-induced inflammatory bowel disease in scid mice with defined flora; Shomer NH et al.; Helicobacter bilis has been isolated from aged inbred mice with multifocal chronic hepatitis and from scid mice with diarrhea, proliferative typhlitis, and colitis . To determine the pathogenic potential of H . bilis, we inoculated 4-week-old female Tac:Icr:Ha(ICR)-scidfDF mice by intraperitoneal injection of approximately 10(8) CFU of H . bilis in phosphate-buffered saline (PBS) (n = 15) or PBS alone (n = 10) and necropsied them at 7 weeks postinfection . Sham-inoculated mice had no significant gross or histopathological findings . In contrast, all 15 experimentally inoculated mice (confirmed to be H . bilis-colonized by culture and PCR of cecal contents) exhibited varying degrees of inflammatory bowel disease (IBD) . Proliferative typhlocolitis was characterized by focal to segmental areas of crypt hyperplasia and a predominantly histiocytic inflammatory cell infiltrate . Labeling indices for 5-bromo-2'-deoxyuridine incorporation were increased approximately 2.5-fold in the ceca and colons of H . bilis-inoculated mice . This is the first study to demonstrate experimentally that infection with H . bilis causes IBD in scid mice with defined flora . This result both confirms a pathogenic role for H . bilis in mice and provides a new model relating a specific microbial agent and IBD.

Lett Appl Microbiol, 1997 Oct, 25(4), 303 - 7
PCR amplification of crude microbial DNA extracted from soil; Yeates C et al.; A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types . DNA was extracted from 100 g of soil using direct lysis with glass beads and sodium dodecyl sulphate (SDS) followed by polyethylene glycol precipitation, potassium acetate precipitation, phenol extraction and isopropanol precipitation . The crude extract could be used in PCR directed at high-copy number (bacterial small subunit rRNA) and single-copy (fungal beta-tubulin) genes.

Scand J Immunol, 1997 Oct, 46(4), 349 - 57
Regional phenotypic specialization of intraepithelial lymphocytes in the rat intestine does not depend on microbial colonization; Helgeland L et al.; Recent studies in mice and humans have provided evidence for regional specialization of gut intraepithelial lymphocytes (IEL) . Here the authors report striking regional variability in the composition of IEL in rat small and large intestine . Two-colour immunofluorescence in situ analysis showed that the distribution of the CD3+ and CD3- IEL subpopulations varied, the proportion of T cells (CD3+) being higher in the ileum than in the jejunum and smallest in the colon . These differences were explained by variable numbers of the T-cell receptor (TCR)alpha/beta + (both CD8+ and CD4+) but not the TCR gamma/delta + subset . Moreover, the various IEL subpopulations showed distinct intraepithelial distribution patterns with CD4+ and CD8 alpha beta + T cells situated near the lamina propria, while CD3- IEL were located preferentially towards the adluminal part of the epithelium . Regional phenotypic variation did not depend on intestinal colonization because analogous results were obtained in germ-free rats . Conventionalization nevertheless caused a marked relative increase of small intestinal TCR alpha/beta + but not TCR gamma/delta + IEL . This increase was more sustained in the jejunum than ileum and eventually reduced the phenotypic IEL differences between the two sites . By contrast, microbial colonization of the colon induced only a transient increase of intraepithelial TCR alpha/beta + cells with no permanent phenotypic alterations . Both CD3+ and CD3- IEL contained subpopulations that expressed NKR-P1 independent of intestinal colonization . These results demonstrate phenotypic specialization of IEL at different levels of the gut and suggest that the indigenous flora is not essential to this end.

J Vet Pharmacol Ther, 1997 Oct, 20(5), 333 - 49
Drugs in salmonid aquaculture--a review; Burka JF et al.; In contrast to mammalian therapeutics, the use of pharmaceutical substances is rather limited in fish . It is basically restricted to anaesthetic agents and anti-infective agents for parasitic and microbial diseases . Anaesthetic agents are used primarily in fish farm and laboratory settings to provide analgesia and immobilization of fish for minor procedures . The anti-infective agents are used for controlling diseases and the choice of drug depends on efficacy, ease of application, human safety, target animal safety including stress to the fish, environmental impact, regulatory approval, costs, and implications for marketing the fish . In this article, the major drugs used in salmonids in North America and Europe will be reviewed and some insight into future directions for drug development and use for the salmonid industry will be introduced . The mechanisms of action, pharmacokinetics, side effects, and uses of the drugs are emphasized.

West Afr J Med, 1997 Jul-Sep, 16(3), 126 - 32
Socio cultural factors in leprosy: implications for control programmes in the post leprosaria abolition years in Nigeria; Nwosu CM et al.; A questionnaire was administered to 53 male and female leprosy patients aged 17-78 years, randomly selected from four clinics in two Local Government Areas of the Eastern part of Nigeria to determine the impact of socio cultural factors on, and also to predict the chances of compliance at, leprosy control measures . About 60% of the patients indicated that traditional concepts were the likely factors explaining the aetiology of leprosy . Four patients were convinced about the microbial aetiology of leprosy . Traditional concepts of leprosy aetiology were significantly associated with mode of entry into the control programme (P < 0.025) and tendency to live within the vicinity of the leprosy clinics (P < 0.01) but not with clinic attendance rate of leprosy patients . The distance of patient's abode from clinic attended, some formal education and whether or not patient's spouses were alive, were not significantly associated with clinic attendance rate . There was a significant association between maleness, age less than 55 years (P < 0.025) as well as negative family attitude (P < 0.05) and irregular clinic attendance . Its implications therefore are to broadly categorize these at risk group at first contact and target towards them patient-holding methods as well as health education, targetted towards patients, their relations and the community.

Appl Environ Microbiol, 1997 Oct, 63(10), 3789 - 96
Increased species diversity and extended habitat range of sulfur-oxidizing Thiomicrospira spp; Brinkhoff T et al.; We combined traditional cultivation methods and new molecular techniques to study the diversity and habitat range of bacteria of the genus Thiomicrospira . Specific primers were designed and used in the PCR to amplify the 16S ribosomal DNA (rDNA) of Thiomicrospira spp . and thus detect the presence of these bacteria in environmental samples and enrichment cultures . By using this genus-specific PCR, we were able to amplify 722-bp-long 16S rDNA fragments from different saltwater habitats as well as from a freshwater ecosystem . Furthermore, we were able to isolate most of these bacteria in pure culture by using enrichment cultures for chemolithoautotrophic sulfur-oxidizing bacteria . With denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA fragments followed by hybridization analysis with one of the primers as a genus-specific probe, it was possible to monitor the success of isolation . The combined approach resulted in the isolation of several chemolithoautotrophic bacteria from different habitats: e.g., a coastal sediment along the coast of Chile, a microbial mat of the hypersaline pond Solar Lake (Sinai, Egypt), and the saline spring Artern (Thuringia, Germany) . In addition, four different isolates were obtained from sediment and water samples taken at Jadebusen, which is part of the German Waddensea . Comparative analysis of the nearly complete 16S rRNA sequences of these isolates indicated several new species, all grouping with the Thiomicrospira species of the gamma subdivision of the class Proteobacteria . A freshwater Thiomicrospira species could not be isolated, but sequence analysis of the PCR product obtained after amplification of the environmental DNA with the Thiomicrospira-specific primers revealed its phylogenetic affiliation . The study indicates an increased species diversity of Thiomicrospira and the ubiquity of this sulfur-oxidizing bacterium in habitats with reduced sulfur compounds.

J Dent Res, 1997 Oct, 76(10), 1637 - 43
Salivary cholesterol of healthy adults in relation to serum cholesterol concentration and oral health; Karjalainen S et al.; Salivary lipids are mostly glandular in origin, but some are believed to diffuse directly from serum . This diffusion and the role of salivary lipids in oral health have scarcely been studied . Therefore, the serum and saliva cholesterol concentrations and oral health were analyzed in a group of healthy adults (n = 139; 64 men and 75 women; 34.2 +/- 5.2 yrs) . Paraffin-stimulated whole saliva was collected, centrifuged (10,000 x g; 30 min, 4 degrees C), and lyophilized, and the cholesterol and other neutral lipids were extracted, separated by thin-layer chromatography, and quantified . The mean +/- SD (range) of saliva cholesterol concentration was 1.20 +/- 0.75 (0.02-5.46) mumol/L, and the saliva cholesterol level of men (1.36 +/- 0.85 mumol/L) was significantly higher than that of women (1.06 +/- 0.64 mumol/L; p < 0.05) . Weak positive correlations between saliva and serum cholesterol concentrations and saliva cholesterol and serum non-high-density lipoprotein cholesterol concentrations were found (r = 0.22, p < 0.05; r = 0.28, p < 0.005, respectively) . The saliva cholesterol assay detected subjects with high (> or = 6.5 mmol/L) serum cholesterol values, with sensitivity and specificity values of 100% and 29%, respectively . A positive correlation between the body mass index and the level of saliva cholesterol concentration was also found (r = 0.31 p < 0.01) . Oral health, microbial counts, or saliva flow rate revealed no differences in subjects with low and high salivary cholesterol level . We conclude that, in healthy adults, saliva cholesterol concentration reflects serum concentration to some extent and can be used to select individuals with high serum cholesterol levels.

Recenti Prog Med, 1997 Sep, 88(9), 415 - 21
Cutaneous involvement in leukaemic patients . A review of the literature and personal experience; Quaglino D et al.; The authors, on the basis of a review of the literature and on their personal experience, derived from the observation of 169 cases of acute and chronic leukaemias, describe the different aspects of the cutaneous lesions present during the course of these neoplastic conditions . The cutaneous lesions, subdivided according to the type of leukaemia, show an extremely variable pattern and it is therefore difficult to differentiate on the basis of the sole macroscopic appearances, specific leukaemic nodules or infiltrates from dermatoses due to bacterial, viral and fungal infections on which an haemorrhagic component may be superimposed . Similarly, if a clearly established diagnosis of leukaemia has not been confirmed, it is difficult to distinguish leukaemic infiltrates from cutaneous lesions caused by a malignant lymphoma, metastatic carcinoma, an eosinophilic granuloma, or from benign lymphohistiocytic infiltrates, secondary to cutaneous infections . It is important also to bear in mind the development of skin eruptions, often with an haemorrhagic component, due to acquired sensitivity to numerous agents, cytostatic drugs, antibiotics, blood products and others, used in therapy . The authors therefore underline the importance of an early recognition of an infectious lesion, often complicated by a previous haemorrhagic event or secondary to microbial invasion of a catheter tip or of a venipuncture site, and consequently, the authors emphasize the need to distinguish these non-specific skin alterations, amenable to appropriate treatment from those lesions due to the development of a skin tumour or to a leukaemic infiltrate, which is nearly always indicative of a leukaemia recurrence or extension of the leukaemic process.

Int J Exp Pathol, 1997 Jun, 78(3), 163 - 8
Phenotypic variation in hamster bronchial mucous cells induced by different airway irritants; Jamil S et al.; Chronic mucus hypersecretion (CMH), a common feature of various obstructive pulmonary diseases, is caused by a variety of airway irritants . Bronchial mucous cell metaplasia (MCM), a histological correlate of CMH, can be induced in hamster airways by a number of different irritants . Previous studies with the hamster model suggest that the secretory cell response to different agents is not stereotyped but can vary in the type of mucus glycoconjugate produced . The present ultrastructural study was conducted therefore to provide quantitative evidence of phenotypic variation in mucous cells induced independently by exposure to the metaplastic agents elastase and acid . HPA-gold lectin cytochemistry revealed an increase in N-acetyl galactosamine at the cell surface and secretory granules of mucous cells in elastase-treated vs . acid-treated animals . Although there was no quantitative difference between the acid-treated and untreated groups, a difference in the pattern of binding within granules indicated variation in the secretory product . Because mucus glycoconjugates serve as attachment sites for specific pathogens, phenotypically distinct mucous cells may promote differential microbial colonization . In humans therefore, variation in the severity and progression of CMH may be due in part to secretory cell susceptibility and response to different pathogenic stimuli.

Arch Tierernahr, 1997, 50(4), 301 - 19
Nutritional significance of phytic acid and phytase; Pallauf J et al.; In the nutrition of monogastric animals phytate-P represents a poorly available source of phosphorus, especially in the case of diets low in phytase activity . Similarly the bioavailability of different minerals and trace elements is considerably reduced by phytate complexes . High concentrations of Ca increase the anti-nutritive effect of phytic acid on mineral and trace element bioavailability and thus impede the action of phytase . This effect can in part be compensated by an increased supply of vitamin D . There is also evidence for protective functions of phytic acid such as the prevention of the formation of free radicals, the delaying of post prandial glucose absorption, the decrease in plasma cholesterol and triglycerides as well as a change in the carry over of heavy metals . The basic mechanisms by which phytic acid may exert these effects are still not clear . In several studies reported in the literature, evidence for the nutritional significance and ecological importance of microbial phytase for pigs and poultry has been given . As the monogastric organism contains no or only negligible amounts of endogenous phytase in the stomach and small intestine, it is therefore dependent on plant or microbial phytase . Plant phytase, e.g . from rye, triticale, wheat or, in smaller amounts from barley, and supplemented Aspergillus-phytase display cumulative effects.

J Parasitol, 1997 Oct, 83(5), 815 - 8
Pathogenicity of the entomopathogenic fungus Metarhizium anisopliae (Deuteromycetes) to Ixodes scapularis (Acari: Ixodidae); Zhioua E et al.; The entomopathogenic fungus Metarhizium anisopliae is highly pathogenic to the black-legged tick, Ixodes scapularis . Spore concentrations of 10(8)/ml for engorged larvae and 10(7)/ml for engorged females resulted in 100% tick mortality, 2 wk postinfection . The LC50 value for engorged larvae (concentration to kill 50% of ticks) was 10(7) spores/ml . Metarhizium anisopliae shows considerable potential as a microbial control agent for the management of Ixodes scapularis.

Annu Rev Microbiol, 1997, 51, 285 - 310
Microbial aldolases and transketolases: new biocatalytic approaches to simple and complex sugars; Takayama S et al.; Enzymes have become exceedingly valuable tools in organic synthesis as the reactions they catalyze generally proceed under mild conditions and in high stereo- and regioselectivity . Advances in microbiology and genetic engineering have greatly increased the availability of various enzymes . One of the most useful applications of enzyme-catalyzed chemical transformations is in the synthesis of water-soluble, polyfunctional organic molecules such as carbohydrates . As the pivotal roles that carbohydrates play in biological processes become more evident, access to these compounds becomes increasingly important . This review gives a brief overview of the use of aldolases and transketolases in the synthesis of sugars, sugar analogs, and related compounds.

J Biolumin Chemilumin, 1996 Nov-Dec, 11(6), 297 - 301
Use of a newly developed rapid microbial ATP bioluminescence assay to detect microbial contamination on poultry carcasses; Siragusa GR et al.; A newly developed rapid microbial ATP bioluminescence test (R-mATP) was shown to be an adequate means to assay the microbial load of poultry carcasses . This assay utilizes differential extraction and filtration to separate somatic from microbial ATP in a very rapid timeframe . The assay requires approximately 5 min to complete; approximately 3.5 min to sample and 90 s analytical time . Correlation coefficient (r) between aerobic colony counts and R-mATP test results (n=329) was 0.82 . Post-test probabilities to correctly classify carcasses with different levels of microbial contamination were as high as 98% for samples of > or = 3.5 log aerobic CFU per ml . Given the rapidity of this assay, the R-mATP holds potential for monitoring the microbial load of carcasses at poultry-processing critical control points . Other potential applications of this new version of the microbial ATP bioluminescence test are discussed.

Biodegradation, 1997, 8(2), 125 - 33
Introduction and PCR detection of Desulfomonile tiedjei in soil slurry microcosms; el Fantroussi S et al.; The aim of this work was to test the feasibility of introducing an anaerobic microbial reductive dechlorination activity into non sterile soil slurry microcosms by inoculation with the pure anaerobic bacterial strain Desulfomonile tiedjei, which is capable of dechlorinating 3-chlorobenzoate to benzoate . To show that the bacterium was established in the microcosms we followed the expression of the reductive dechlorination activity and a molecular probe based on PCR amplification of the 16S rDNA gene was developed . However, the success of PCR amplification of the 16S rDNA gene depends on the DNA extraction and purification methodologies applied, as shown through the use of several protocols . In this study we report a DNA extraction and purification method which generates sufficient and very clean DNA suitable for PCR amplification of the D . tiedjei 16S rDNA gene . The threshold of detection was about 5.10(3) bacteria per gram of soil slurry . Introduction of D . tiedjei in soil slurry microcosms proved successful since 3-chlorobenzoate dechlorination activity was established with this bacterium in microcosms normally devoid of this dechlorination capacity . Indeed, the addition of D . tiedjei to microcosms supplemented with acetate plus formate as cosubstrate, at their respective concentrations of 5 and 6 mM, led to a total biotransformation of 2.5 mM of 3-chlorobenzoate within 12 days . After complete 3-chlorobenzoate dechlorination, the 16S rDNA gene of this bacterium was specifically detected only in the inoculated microcosms as shown by PCR amplification followed by restriction mapping confirmation.

Plant Physiol, 1997 Oct, 115(2), 437 - 51
Regulation of sesquiterpene cyclase gene expression . Characterization of an elicitor- and pathogen-inducible promoter; Yin S et al.; The promoter for a tobacco (Nicotiana tabacum) sesquiterpene cyclase gene, a key regulatory step in sesquiterpene phytoalexin biosynthesis, has been analyzed . The EAS4 promoter was fused to the beta-glucuronidase (GUS) reporter gene, and the temporal and spatial expression patterns of GUS activity were examined in stably transformed plants and in transient expression assays using electroporated protoplasts of tobacco . No GUS activity was observed in any tissues under normal growth conditions . A low level of GUS activity was detected in wounded leaf, root, and stem tissues, whereas a much higher level was observed when these tissues were challenged with elicitors or microbial pathogens . The GUS expression pattern directed by the EAS4 promoter was identical to the induction patterns observed for the endogenous sesquiterpene cyclase genes . Neither exogenous salicylic acid nor methyl jasmonate induced GUS expression; and H2O2 induced GUS expression to only a limited extent . Although the EAS4 promoter contains cis-sequences resembling previously identified transcriptional control motifs, other cis-sequences important for quantitative and qualitative gene expression were identified by deletion and gain-of-function analyses . The EAS4 promoter differs from previously described pathogen-/elicitor-inducible promoters because it only supports inducible gene expression and directs unique spatial expression patterns.

Eur J Immunol, 1997 Sep, 27(9), 2269 - 78
Proteasome regulation of Fas ligand cytotoxicity; Matsui K et al.; The role of NF-kappa B in regulating FasL-mediated cytotoxicity was investigated by using lactacystin . Lactacystin is a microbial metabolite known to inhibit only the protease activity of the proteasome, which is required for NF-kappa B translocation . When activated by immobilized anti-CD3 monoclonal antibody, hybridoma T cells (5D5) degraded I kappa B beta, translocated NF-kappa B into the nucleus, transcribed immediate-early genes and the Fas ligand (FasL) gene, and expressed FasL-mediated cytotoxicity . Lactacystin strongly blocked I kappa B beta degradation and the translocation of NF-kappa B (p50/RelA heterodimer), but had little effect on the expression of the transcription factors, Oct-1 and AP-1 . Moreover, lactacystin did not inhibit the nuclear translocation of NF-ATp whereas cyclosporin A inhibited the translocation of both NF-kappa B and NF-ATp . The expression of c-myc and nur77, two immediate-early genes implicated in FasL gene activation, was blocked by lactacystin . Subsequently, the expression of FasL gene and FasL-mediated cytotoxicity was inhibited . LLnL, a well-known peptide aldehyde which inhibits the protease activities of the proteasome and cysteine proteases, also inhibited NF-kappa B translocation and FasL-mediated cytotoxicity . However, these events were not inhibited by the highly specific cysteine protease inhibitor E64 . These observations provide further evidence that FasL cytotoxicity is regulated by the proteasome . Furthermore, lactacystin must be added early in order to efficiently inhibit the induction of FasL cytotoxicity, indicating that the early events are critical for FasL gene activation . Our study integrates the proteasome-dependent I kappa B degradation and NF-kappa B translocation into a T cell activation cascade which results in FasL gene activation and the expression of FasL-mediated cytotoxicity.

Rev Environ Contam Toxicol, 1997, 153, 1 - 64
Environmental fate of trifluralin; Grover R et al.; Trifluralin, a preemergence, soil-applied and soil-incorporated herbicide, has been in agricultural use since 1963 . The environmental chemistry and fate of dinitroaniline herbicides, including trifluralin, has been studied extensively in agricultural soils . Probst et al . (1975) and Helling (1976) have summarized pre-1975 data on the mobility, persistence, and degradation or metabolism of dinitroaniline herbicides as a group . Since then, numerous studies have been carried out on the fate of dinitroanilines, especially trifluralin, in the environment to understand further their degradation in soil, potential for mobility and persistence, and environmental concentration in water and air . The present review, while summarizing briefly earlier data, concentrates primarily on the post-1975 data on degradation, mobility, and persistence of trifluralin in soils and its potential concentrations in water and air . Trifluralin is readily degraded under sunlight in all media, with half-lives (t1/2) of minutes to several months, depending on the substrate . In addition, other dissipation processes, such as microbial and chemical, are also operative in soils, water, and sediments . Several degradation products of trifluralin have been identified and characterized, both under photolysis and following aerobic and anaerobic metabolism in soils and water-sediment systems . The differences between various degradative pathways of trifluralin appear to be more quantitative than qualitative in nature, leading eventually to the same end products that are subject to binding or mineralization with time . The general lack of accumulation of the breakdown products of trifluralin suggests that these are also subject to the same degradative mechanisms as the parent compound . Trifluralin has low water solubility and is strongly bound to soil components; mean Koc values range from 4,000 to 13,000 . Once applied and incorporated into the soil, trifluralin remains relatively immobile with minimal or no potential for contamination of groundwaters under or near the treated zones . Trifluralin residues in soil surface layers are subject to loss via transport in runoff water or volatilization into the air . Seasonal losses in surface runoff are consistently less than 0.5% of the amounts applied, with concentrations in edge-of-the-field run-off water typically < 1.0 microgram L-1 . Consequently, trifluralin is infrequently detected in surface waters and, if present, usually occurs below levels of quantification . Seasonal trifluralin losses into the atmosphere can be as high as 25% of that applied . Maximum trifluralin residues in the air above treated fields are in the 2-3 micrograms m-3 range following application, decreasing to < 100 ng m-3 in ambient air of intensive use areas, indicating its rapid dissipation in air . Trifluralin residues at < 100 pg m-3 in the atmosphere of remote nonuse regions have been reported, suggesting its potential for long-range transport . However, there is a general lack of understanding of the mechanisms controlling its potential for long-distance transport, especially considering its rapid photodegradation in vapor and solution states . The persistence of trifluralin in agricultural soils following incorporation is highly variable, depending on several factors such as depth of incorporation, soil moisture, soil temperature, soil air, and soil organic matter content . Estimated half-lives under a variety of agronomic conditions range from 25 to > 201 d, thus categorizing its persistence from 'moderate' to 'persistent' . The estimated half-life data for trifluralin under agronomic conditions, however, cannot be extrapolated to other potential scenarios, such as its dissipation in nontarget areas where trifluralin residues, if any, are essentially deposited on surfaces . Surface deposits on nontarget areas, unlike soil-incorporated residues, would be subject to volatilization and photolysis and thus more short lived . (ABSTRACT TRUNCATED)

J Biol Chem, 1997 Oct 24, 272(43), 27218 - 23
cDNA cloning, tissue distribution, and identification of the catalytic triad of monoglyceride lipase . Evolutionary relationship to esterases, lysophospholipases, and haloperoxidases; Karlsson M et al.; Monoglyceride lipase catalyzes the last step in the hydrolysis of stored triglycerides in the adipocyte and presumably also complements the action of lipoprotein lipase in degrading triglycerides from chylomicrons and very low density lipoproteins . Monoglyceride lipase was cloned from a mouse adipocyte cDNA library . The predicted amino acid sequence consisted of 302 amino acids, corresponding to a molecular weight of 33,218 . The sequence showed no extensive homology to other known mammalian proteins, but a number of microbial proteins, including two bacterial lysophospholipases and a family of haloperoxidases, were found to be distantly related to this enzyme . By means of multiple sequence alignment and secondary structure prediction, the structural elements in monoglyceride lipase, as well as the putative catalytic triad, were identified . The residues of the proposed triad, Ser-122, in a GXSXG motif, Asp-239, and His-269, were confirmed by site-directed mutagenesis experiments . Northern blot analysis revealed that monoglyceride lipase is ubiquitously expressed among tissues, with a transcript size of about 4 kilobases.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 557 - 71
DRINK: a biogeochemical source term model for low level radioactive waste disposal sites; Humphreys P et al.; Interactions between element chemistry and the ambient geochemistry play a significant role in the control of radionuclide migration in the geosphere . These same interactions influence radionuclide release from near surface, low level radioactive waste, disposal sites once physical containment has degraded . In situations where LLW contains significant amounts of metal and organic materials such as cellulose, microbial degradation in conjunction with corrosion can significantly perturb the ambient geochemistry . These processes typically produce a transition from oxidising to reducing conditions and can influence radionuclide migration through changes in both the dominant radionuclide species and mineral phases . The DRINK (DRIgg Near field Kinetic) code is a biogeochemical transport code designed to simulate the long term evolution of the UK low level radioactive waste disposal site at Drigg . Drigg is the UK's principal solid low level radioactive waste disposal site and has been receiving waste since 1959 . The interaction between microbial activity, the ambient geochemistry and radionuclide chemistry is central to the DRINK approach with the development of the ambient pH, redox potential and bulk geochemistry being directly influenced by microbial activity . This paper describes the microbial aspects of the code, site data underpinning the microbial model, the microbiology/chemistry interface and provides an example of the code in action.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 545 - 56
Microbiology in nuclear waste disposal: interfaces and reaction fronts; McKinley IG et al.; It is now generally acknowledged that microbial populations will be present within nuclear waste repositories and that the consequences of such activity on repository performance must be assessed . Various modelling approaches--based either on mass balance/thermodynamics or on kinetics--have been developed to provide scoping estimates of the possible development of these populations . Past work has focused on particular areas of the repository which can be considered relatively homogeneous and hence can be represented by some kind of 'box' or 'mixing tank' . In reality, however, waste repositories include a range of engineering materials (steel, concrete, etc.) which are emplaced at depth in a rock formation . Strong chemical gradients--of the type which may be exploited by lithoautotrophic microbial populations--are likely to be found at the contacts between different materials and at the interface between the engineered structures and the host rock . Over the long timescales considered, solute transport processes will cause the locations of strong chemical gradients to move, forming reaction fronts . The high-pH plume resulting from the leaching of cement/concrete in some repository types is a particularly important example of such a reaction front . Redox fronts, which may occur in different areas of all kinds of repositories, also play an important role and would be locations where microbial activity is likely to be significant . In this paper, the key microbial processes expected at (or around) interfaces and fronts will be discussed, with particular emphasis on the development of quantitative models . The applicability of the models used wil be tested by considering similar fronts which can be found in natural systems.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 539 - 44
Degradation of ethylenethiourea (ETU) in oxic and anoxic sandy aquifers; Jacobsen OS et al.; Ethylenethiourea is an important degradation product of ethylenebisdithiocarbamate fungicides, which are widely used in different kinds of crops . The ethylenebisdithiocarbamate group includes maneb, zineb and mancozeb . The ethylenebisdithiocarbamates are not highly toxic and degrade rapidly in the presence of moisture and oxygen, forming different compounds . One of these is the polar ethylenethiourea, which is relatively stable . Thus, this compound appears to be a potential contaminant for groundwater . Batch experiments were carried out under biotic as well as abiotic conditions to study the degradation dependence of concentration, temperature and organic matter . The decomposition of ethylenethiourea under abiotic conditions was found to be less than 5% of the degradation under biotic conditions . Further, ethylenethiourea showed to be stable over a period of 150 days at 20 degrees C in tap water as well as in batch with soil sterilized with NaN3 . The degradation of ethylenethiourea depends on the concentration in the water implying first order reaction kinetics . The microbial degradation of ethylenethiourea is highly temperature dependent with aerobic Q10 between 2.9 and 4.2, and an anaerobic between 2.1 and 2.5 . A minor increase in degradation rates was observed by application of nitrate and manure to the batches . The experiments show extremely complete degradation of ethylenethiourea in the presence of microbial nitrate reduction with pyrite which occurs in deeper parts of the aquifers.

Ciba Found Symp, 1997, 203, 94 - 104; discussion 104-8, 139-40
Health impacts of large releases of radionuclides . Roles of micro-organisms in the environmental fate of radionuclides; Gadd GM; Micro-organisms play important roles in the environmental fate of radionuclides in both aquatic and terrestrial ecosystems, with a multiplicity of physico-chemical and biological mechanisms effecting changes in mobility and speciation . Physico-chemical mechanisms of removal, which may be encompassed by the general term 'biosorption', include adsorption, ion exchange and entrapment . These are features of living and dead organisms as well as their derived products . In living cells biosorptive processes can be directly and indirectly influenced by metabolism, and may be reversible and affected by changing environmental conditions . Metabolism-dependent mechanisms of radionuclide immobilization include metal precipitation as sulfides, sequestration by metal-binding proteins and peptides, and transport and intracellular compartmentation . Chemical transformations of radionuclide species, particularly by reduction, can result in immobilization . Microbial processes involved in solubilization include autotrophic and heterotrophic leaching, complexation by siderophores and other metabolites, and chemical transformations . Such mechanisms are important components of natural biogeochemical cycles for radionuclides and should be considered in any analyses of environmental radionuclide contamination . Several micro-organism-based biotechnologies, e.g . those based on biosorption or precipitation, are of potential use for the treatment of radionuclide contamination.

Clin Exp Immunol, 1997 Sep, 109(3), 468 - 72
Chronic sinusitis refractory to standard management in patients with humoral immunodeficiencies; Buehring I et al.; Chronic refractory sinusitis is a common feature in patients with primary immunodeficiencies . The efficacy of standard therapeutic strategies is questionable . In an open trial we evaluated the efficacy of azithromycin, N-acetylcysteine and topical intranasal beclomethasone (100 microg twice daily for 6 weeks) in 16 patients with primary immunodeficiencies (median age 13.5 years, range 5-32 years) . All patients suffered from chronic sinusitis despite regular immunoglobulin replacement therapy every 3 weeks . Magnetic resonance imaging (MRI) scans were performed before and after 6 weeks of treatment to evaluate morphological changes in the paranasal sinuses . Nasal swabs and washings were taken for microbial analysis and measurement of inflammatory mediators (IL-8, tumour necrosis factor-alpha (TNF-alpha), eosinophilic cationic protein (ECP)) before and post therapy . Inflammatory mediators in nasal secretions were significantly elevated in patients: IL-8 median 2436 pg/ml (range 441-5435 pg/ml), TNF-alpha 37.3 pg/ml (3.75-524 pg/ml) and ECP 33 ng/ml (1.5-250 ng/ml) versus age-matched healthy controls: IL-8 median 212 pg/ml (99-825 pg/ml), TNF-alpha 3.77 pg/ml (2.8-10.2 pg/ml) and ECP 1.5 ng/ml (1.5-14.8 ng/ml) (P < 0.0001) . Inflammation of the maxillary sinuses was confirmed by MRI scans in all patients, additionally infection of the ethmoidal and frontal sinuses was recorded in five patients . Bacterial growth appeared in 11 out of 16 cultures . In spite of therapy, no improvement in sinal inflammation visualized by MRI was achieved . Moreover, no significant decrease in pathogens and levels of inflammatory mediators could be detected (IL-8 1141 pg/ml, 426-4556 pg/ml; TNF-alpha 13.9 pg/ml, 4.1-291.6 pg/ml; ECP 32.3 ng/ml, 3.7-58.4 ng/ml) . Our results demonstrate that conventional management of sinusitis is of little benefit in patients with chronic refractory sinusitis with an underlying immunodeficiency . More studies are needed to test antibiotic regimens, probably combined with surgical drainage and anti-inflammatory agents.

Microb Ecol, 1997 Nov, 34(3), 199 - 209
Microbial Food Webs in Marine Sediments . II . Seasonal Changes in Trophic Interactions in a Sandy Tidal Flat Community
Epstein SS.
>AbstractThe role of grazing by marine sediment flagellates, ciliates, and meiobenthic animals in controlling production of their bacterial and diatom prey was investigated . At six selected time points, over the year, bacterial production and diatom standing stock were compared to grazing pressure exercised by proto- and micrometazoan consumers . The intensity of prey-predator relations showed pronounced yearly dynamics in which two stages could be distinguished . During the first phase, from the end of winter to mid-summer, the consumption of diatoms gradually increased, with possible overgrazing at the end of the period . This was followed by a collapse of diatom abundance, to the winter level . During the first stage, no appreciable bacterial consumption was observed in spite of the high abundance and production of bacteria . The second stage started in mid-summer and continued through the fall . During this period, the grazing on bacteria increased and reached the year's maximum . For at least a brief period (October), micrograzers removed the majority of bacterial production . In contrast, herbivory stayed at the year's lowest level, and diatoms appeared to be controlled by factors other than grazing . The observed ingestion rates seem to support the apparent energy requirements of flagellates and some ciliates (scuticociliates and hypotrichids) . Other ciliates (pleurostomatids and karyorelictids) could not subsist on the observed diet and might have to complement it with other energy sources, possibly via dissolved organic matter absorption.

J Anim Sci, 1997 Oct, 75(10), 2813 - 23
Effects of dietary nitrogen source and concentration in high-grain diets on finishing steer performance and nutrient digestion; Milton CT et al.; Two experiments were designed to evaluate dietary N source and concentration on finishing steer performance and nutrient digestion . In Exp . 1, 100 steers were used in a randomized complete block design experiment with 2 x 2 + 1 factorially arranged treatments . Diets contained 1.93 or 2.24% N supplemented by urea or soybean meal (SBM), or 2.24% N supplemented by cottonseed meal (CSM) . Steers fed SBM-supplemented diets gained 13% faster (P < .01) and were 9% (P < .01) more efficient converting feed to gain than steers receiving urea . Steers fed diets containing 2.24% N were 4% (P < .05) more efficient than those fed diets containing 1.93% N . Steers fed CSM-supplemented diets gained 6% (P < .10) less efficiently than steers receiving SBM . Increasing dietary N with urea from 1.93 to 2.24% decreased carcass weights 3%, whereas increasing dietary N with SBM increased carcass weights 3% . Carcass-adjusted gains were reduced 8% by increasing urea from .9 to 1.5% but increased 7% by increasing SBM from 6.1 to 10.5% of DM . In Exp . 2, four ruminally and duodenally cannulated steers (390 kg) were used in a 4 x 4 Latin square design experiment to evaluate urea and SBM supplementation on digestion . Diets contained no supplemental N, 1.84% N with urea or SBM as the supplement, or 2.16% N with SBM as the supplement . Total tract starch digestion, duodenal microbial N flow, and efficiency of microbial protein synthesis in the rumen were higher (P < .10) in steers fed SBM- than in those fed urea-supplemented diets . Supplementation with SBM increased metabolizable protein supply and dietary energy utilization.

J Physiol Pharmacol, 1997 Sep, 48(3), 307 - 14
The versatility of Helicobacter pylori in the adaptation to the human stomach; Blaser MJ; A growing body of data indicates that H . pylori colonization of human is ancient, which is consistent with its high prevalence, chronicity of carriage, and generally low level of disease, which, when it occurs has only marginal or no effects on host reproductive capacity . All of these phenomena are markers for a relatively benign co-existence, which may include all of the entire spectrum of interactions from parasitism, through commensalism, to symbiosis . Recent studies suggest the emergence of "quasispecies" during prolonged colonization, and the presence of multiple strains colonizing individual hosts . Such observations suggest that concepts of competition between strains and mutualism will be important in understanding the ecology of colonization and its effects on hosts . The presence of particular pathologies in the host may in part be a function of the characteristics of the bacterial population present . At a genomic level, H . pylori appears to adapt to changing conditions by point mutation, genomic rearrangement, and horizontal gene transfer, the latter is favored by its natural competence . The ability of H . pylori to alter phenotypic properties including superficial Lewis antigen expression and secretion of proinflammatory molecules is evidence of its sensitivity to environmental signals from the host . In such a universe, disease outcomes such as ulceration or neoplasia may be considered as accidents secondary to microbial persistence.

Glycoconj J, 1997 Sep, 14(6), 699 - 706
Monoclonal antibodies for the detection of desialylation of erythrocyte membranes during haemolytic disease and haemolytic uraemic syndrome caused by the in vivo action of microbial neuraminidase; Seitz RC et al.; Especially in childhood, the in vivo action of microbial neuraminidase may cause haemolytic anaemia or life-threatening haemolytic uraemic syndrome . The exposure of the Thomsen-Friedenreich (T) crypto-antigen and T-antigen polyagglutinability of erythrocytes has been described as the first sign of toxic cleavage of N-acetylneuraminic acid (Neu5Ac) from sialoglycoproteins of cell membranes . This phenomenon may, however, be too unspecific to initiate treatment for toxin elimination . The present study investigated the diagnostic effectiveness of a panel of three monoclonal antibodies (mcabs) for the estimation of the clinical significance of neuraminidase action in vivo . Depending on the amount of Neu5Ac released, the mcabs I-C4, II-Q9 and III-Y12 recognized different epitopes on erythrocyte asialoglycophorin . In 1345 patients, the mcab II-09 detected cleavage of Neu5Ac in 32 children who had T-antigen polyagglutinability and mild to moderate haemolytic anaemia . However, only 10 patients, whose erythrocytes were agglutinated by the mcabs III-Y12 or I-C4, developed severe haemolysis, thrombocytopenia, and finally the life-threatening haemolytic uraemic syndrome (p<0.0002) . In conclusion, these mcabs provided an early marker of the in vivo action of neuraminidase . Two different degrees of erythrocyte desialylation, as defined by these mcabs, are suggested to reflect the severity of toxin-associated disease.

Med Arh, 1996, 50(1-2), 49 - 52
{The effect of Kaviner and the smear layer on dentin permeability of permanent teeth in children}; Tadmiscija H et al.; The dentin permeability is defined as a moving of fluid, of chemical substances and microbial products as well through the dentin . The clinical protection of children permanent teeth in other words the protection of pulp-dentin complex after their preparation makes a big problem into the restorative stomatology . Caviner is one of the newer means which is used in the protection of pulp-dentin complex which represents the components of powder dispersing within the ethyl-acetate mixture of polystirol . The important variable in this study is the presence or absence of smearing layer which has the important influence onto the dentin permeability . In order to confirm the Caviner and smearing layer working onto the dentin permeability of the children permanent teeth in vitro experiment was designed . We used for it the dentin disks made of the intact first premolar, extracted because of orthodontic reasons at the ten years old children . They were put into the split chamber which represents a part of apparatus made at our Faculty, which is, in fact, a modified apparatus which was formed by prof . D.H . Pashley (Georgia, USA), and it is used for measuring of dentin permeability with the help of hydraulic conductance (Lp) of dentin . The dentin permeability is expressed by the hydraulic conductance term, but the measures are still expressed as the Lp percentage maximum because of better survey of results . Comparing the obtained results with the other authors results we have come to the similar conclusions, and that is in fact, that the smearing layer significantly reduces the dentin permeability, and that the Caviner, as the other layners, reduces the dentin permeability . If we compare the reduction of dentin permeability at the dentin covered with the smearing layer and with the Caviner, it has been noticed that the smearing layer reduces more significantly . It should be accented that the Caviner reduces the dentin permeability less than the most earlier researched means for the protection of pulp-dentin complex.

J Infect Dis, 1997 Oct, 176(4), 904 - 12
Long-term evaluation of cellular immunity during antiretroviral therapy and immunization with human immunodeficiency virus type 1 (HIV-1) Env glycoprotein in HIV-1-infected persons; Carlesimo M et al.; Cellular immune responses to human immunodeficiency virus type 1 (HIV-1) antigens, microbial recall antigens, and CD3 monoclonal antibody were studied in HIV-1-infected asymptomatic patients in a phase II, double-blind trial of immunization with recombinant HIV-1 gp160 in or not in association with zidovudine . A vigorous and persistent lymphoproliferative response (LPR) to HIV-1 Env antigens was observed in vaccinated patients . Neither Env-specific lymphocyte cytotoxicity nor LPR to recall antigens was significantly influenced by gp160 administration . The induction of LPRs to HIV-1 envelope proteins did not show positive effects on the course of HIV-1 infection . Patients treated with zidovudine alone or in combination with the immunogen showed improvement of T lymphocyte responses and transient reduction of viremia . These results suggest that antiretroviral therapy is more beneficial than immunization with gp160 and should always be considered in association with future vaccination and immunotherapeutic interventions in HIV-1-infected subjects.

J Anim Sci, 1997 Oct, 75(10), 2796 - 802
Escape protein supplementation of steers fed grass silage-based diets; Nelson ML; Beef steers (Trials 1 and 2, 280 +/- 2 kg; Trial 3, 330 +/- 2 kg) were fed diets of 67.5% wheat (Trial 1) or oat silage (Trials 2 and 3), 20.5% barley, and 12% supplement in randomized complete block design growth trials . Dietary treatments were graded levels of supplemental escape protein (EP) from corn gluten meal (Trial 1, 0 to 213 g/d escape protein) or animal by-products (1:1:1 DM mixture of blood, feather, and meat and bone meals, 0 to 223 or 0 to 317 g/d of escape protein in Trials 2 and 3, respectively) to titrate amounts needed to maximize steer live weight gain . As supplemental EP from corn gluten meal increased, steer live weight gain increased linearly (P < .001) and feed-to-gain decreased linearly (P < .001) . Supplementation with 135 g/d of corn gluten meal EP (335 g/d of corn gluten meal) increased average daily gain from .76 to .91 kg/d . As supplemental EP from animal by-products increased, steer live weight gain increased quadratically (P < .05) and feed-to-gain decreased linearly (P < .01) . Supplementation with 223 or 317 g/d of animal by-product EP increased live weight gain by .27 kg/d . Supplemental escape protein was needed to increase live weight gain of steers consuming ensiled forage diets due to low EP contents of silages (7, 3, and 23% of CP in Trials 1, 2, and 3, respectively) and barley (15, 27, and 22% of CP in Trials 1, 2, and 3, respectively) and limited microbial protein synthesis.

Acta Microbiol Immunol Hung, 1997, 44(2), 155 - 64
Changes in water activity and some microbial groups during storage of pet feed; Gomez R et al.; The effect of exposure of different pet feed samples to the typical temperature and moisture conditions of many months of the year (9 degrees C and 80% RH) on water activity (aw), pH and growth of various microbial groups (mesophilic aerobic bacteria, fungi and yeasts) was studied . The storage conditions were found to scarcely influence the samples pH, with no significant changes relative to the initial values (the standard deviation was 0.04 and the coefficient of variation 0.85%) . By effect of exposure to the temperature and moisture conditions tested, the initially stable feeds reached moisture contents close to 20% and aw values near those of equilibrium with the ambient relative humidity during storage . Microbial counts increased with increasing aw, with final means of 8.44, 9.16 and 8.71 log CFU/g for mesophilic aerobic bacteria, fungi and yeasts, respectively . The risk of mycotoxin production at these aw values is discussed . Careful control of moisture is recommended in order to preserve the quality of pet feed throughout its scheduled shelf life.

Infect Immun, 1997 Oct, 65(10), 4288 - 98
Targeted delivery of antigen to hamster nasal lymphoid tissue with M-cell-directed lectins; Giannasca PJ et al.; The nasal cavity of a rodent is lined by an epithelium organized into distinct regional domains responsible for specific physiological functions . Aggregates of nasal lymphoid tissue (NALT) located at the base of the nasal cavity are believed to be sites of induction of mucosal immune responses to airborne antigens . The epithelium overlying NALT contains M cells which are specialized for the transcytosis of immunogens, as demonstrated in other mucosal tissues . We hypothesized that NALT M cells are characterized by distinct glycoconjugate receptors which influence antigen uptake and immune responses to transcytosed antigens . To identify glycoconjugates that may distinguish NALT M cells from other cells of the respiratory epithelium (RE), we performed lectin histochemistry on sections of the hamster nasal cavity with a panel of lectins . Many classes of glycoconjugates were found on epithelial cells in this region . While most lectins bound to sites on both the RE and M cells, probes capable of recognizing alpha-linked galactose were found to label the follicle-associated epithelium (FAE) almost exclusively . By morphological criteria, the FAE contains >90% M cells . To determine if apical glycoconjugates on M cells were accessible from the nasal cavity, an M-cell-selective lectin and a control lectin in parallel were administered intranasally to hamsters . The M-cell-selective lectin was found to specifically target the FAE, while the control lectin did not . Lectin bound to M cells in vivo was efficiently endocytosed, consistent with the role of M cells in antigen transport . Intranasal immunization with lectin-test antigen conjugates without adjuvant stimulated induction of specific serum immunoglobulin G, whereas antigen alone or admixed with lectin did not . The selective recognition of NALT M cells by a lectin in vivo provides a model for microbial adhesin-host cell receptor interactions on M cells and the targeted delivery of immunogens to NALT following intranasal administration.

Poult Sci, 1997 Oct, 76(10), 1424 - 7
Iron bioavailability in soybean meal as affected by supplemental phytase and 1 alpha-hydroxycholecalciferol; Biehl RR et al.; An Fe depletion-repletion chick bioassay was conducted to determine whether supplemental microbial phytase or 1 alpha-hydroxycholecalciferol (1 alpha-OH D3) would improve the bioavailability of Fe in soybean meal (SBM) . Weight gain, hemoglobin, and hematocrit were markedly improved when increasing levels (0, 10, 20, and 80 mg/kg) of Fe from analytical grade ferrous sulfate (FeSO4.7H2O) were added to the Fe-deficient casein-dextrose basal diet containing 20 mg Fe/kg . Addition of 19 mg Fe/kg from SBM to the basal diet improved (P < 0.05) hemoglobin and hematocrit, but the response was less than that obtained from 10 mg Fe/kg from FeSO4.7H2O . Phytase (1,430 units/kg), 1 alpha-OHD3 (10 micrograms/kg), or the combination, added to the SBM-fortified basal diet did not further improve hematocrit or hemoglobin, indicating that Fe bioavailability of SBM was not increased by either of these feed additives . Based on standard-curve methodology, and using hemoglobin as a criterion, the relative bioavailability of Fe was 38.5% for SBM, 21.0% for SBM+phytase, 23.2% for SBM+1 alpha-OHD3, and 29.2% for SBM+phytase+ 1 alpha-OHD3.

Crit Rev Food Sci Nutr, 1997 Aug, 37(5), 471 - 90
Modeling microbial populations with the original and modified versions of the continuous and discrete logistic equations; Peleg M; The life histories of microbial populations, under favorable and adverse conditions, exhibit a variety of growth, decay, and fluctuation patterns . They have been described by numerous mathematical models that varies considerably in structure and number of constants . The continuous logistic equation alone and combined with itself or with its mirror image, the Fermi function, can produce many of the observed growth patterns . They include those that are traditionally described by the Gompertz equation and peaked curves, with the peak being symmetric or asymmetric narrow or wide . The shape of survival and dose response curves appears to be determined by the distribution of the resistance's to the lethal agent among the individual organisms . Thus, exponential decay and Fermian or Gompertz-type curves can be considered manifestations of skewed to the right, symmetric, and skewed to the left distributions, respectively . Because of the mathematical constraints and determinism, the original discrete logistic equation can rarely be an adequate model of real microbial populations . However, by making its proportionality constant a normal-random variate it can simulate realistic histories of fluctuating microbial populations, including scenarios of aperiodic population explosions of varying intensities of the kind found in food-poisoning episodes.

Drugs, 1997, 54 Suppl 1, 24 - 8
From Peyer's patches to tonsils . Specific stimulation with ribosomal immunotherapy; Bene MC et al.; Ribosomal immunotherapy has been successfully used since the 1960s to boost the immune system and provide protection against microbial infections . We have investigated both whether and how these immunostimulants behave as natural immunogens in the mucosa-associated immune system . According to current understanding of the physiology of the mucosal immune response, intestinal Peyer's patches and the related solitary nodules are the primary inductive sites involved in the immune protection of all mucosal surfaces . Sensitised lymphocytes generated at these sites reach the general circulation through lymphatic drainage and relocate in mucosal areas by means of specialised 'high endothelial venules' . We hypothesised that orally administered ribosomal preparations would yield sensitised B cells specific for bacterial antigens from the parent strains . These cells should then be detectable in the peripheral blood after ribosomal intake, and identifiable as plasma cells in mucosae-associated tissues after completing their terminal differentiation . Ultimately, specific IgA should appear in secretions . To this end, we studied the immune responses generated in children and adults after 'Ribomunyl' administration, according to various consecutive protocols . The initial hypothesis was confirmed by the identification of specific B cells in the peripheral blood, plasma cells in the tonsillar tissue and specific IgA in the saliva . An animal model involving the use of twin sheep enabled detection of the specific cells in mesenteric and cervical lymph nodes . Analysis of these data indicates that ribosomal preparations trigger the production of lymphocytes specific for both ribosomes themselves and whole bacterial antigens . This supports the fact that small antigenic motifs are carried as partly synthesised peptides on the ribosomal particles . Therefore, ribosomes boost an array of B cells that are specific for many antigenic determinants of the bacteria from which they are extracted . We were also able to show that the stimulation provided was specific, since no response to other bacteria could be detected . Finally, analysis of the kinetics of this stimulation confirmed that oral immunisation generates rapid and transient secretory responses, building increased numbers of memory cells that are readily available to respond to further challenges by either more ribosomal preparations or potential pathogens.

J Dairy Sci, 1997 Sep, 80(9), 2204 - 12
Potential to alter the content and composition of milk fat through nutrition; Ashes JR et al.; Nutritional manipulation of the rumen ecosystem provides a strategy to alter the content and composition of milk fat . Dietary fat supplements affect the content and composition of milk fat . The magnitude of changes is influenced by the degree of protection; as protection increases, the deleterious effects fatty acids on microbial activity decreases, and biohydrogenation of C18 unsaturated fatty acids is reduced . In addition, change is influenced by the transfer of dietary fat into milk, which is related to fatty acid composition, degree of ruminal metabolism, and efficiency of digestion . A cascade of metabolic events involving specific nutrients (e.g., trans fatty acids and cyclopropene acids) occurs that regulates the activity of key enzymes in pathways of endogenous fat synthesis within the mammary gland . When cattle are fed oilseeds (e.g., canola and cotton) with > 75% protection from biohydrogenation, the proportion of saturated to unsaturated fatty acids is changed, and the fat content of milk is increased . Human consumption of dairy products containing elevated proportions of C18 mono- and polyunsaturated fatty acids reduces the content of cholesterol in plasma low density lipoproteins . These fat-modified dairy products are more susceptible to autoxidation, which can be controlled by including vitamin E in the diet of lactating cow . These products also have much less solid fat, which improves spreadability of butter . By protecting different oilseeds from ruminal metabolism, demands for energy can be satisfied while producing milk fat that can be designed for consumer and manufacturing requirements.

J Nutr, 1997 Oct, 127(10), 2054 - 9
1alpha-hydroxycholecalciferol does not increase the specific activity of intestinal phytase but does improve phosphorus utilization in both cecectomized and sham-operated chicks fed cholecalciferol-adequate diets; Biehl RR et al.; Two chick assays were conducted in an attempt to understand how 1alpha-hydroxylated cholecalciferol compounds {1,25-(OH)2 D3 and 1alpha-OH D3} function in chicks to improve utilization of phytate-bound phosphorus (P) and trace minerals . Mucosal tissue from chicks fed a P-deficient corn-soybean meal diet, with or without supplemental 1alpha-OH D3, was incubated with sodium phytate . Inorganic P (Pi) release from sodium phytate, a measure of mucosal phytase activity, was not influenced by 1alpha-OH D3 presence in the diet . Increasing doses of mucosal protein in tubes containing sodium phytate resulted in marked increases (P < 0.01) in Pi release, but 1alpha-OH D3 in the diet from which the duodenal mucosal tissue was obtained had no effect on Pi release . Similarly, addition of either 1alpha-OH D3 or 1,25-(OH)2 D3 directly to the incubation tubes had no effect on Pi production . Efficacy of supplemental 1alpha-OH D3 and phytase was also tested in cecectomized vs . sham-operated chicks that were fed P-deficient and cholecalciferol-adequate corn-soybean meal diets . Removal of the twin ceca was done in an attempt to remove much of the intestinal microbial activity, and in turn, much of the gut microbial phytase activity . Marked increases (P < 0.01) in bone ash occurred in response to phytase or 1alpha-OH D3 supplementation, and cecectomized birds responded to either addition in the same manner as sham-operated controls . The data suggest that the marked phytate-P releasing capacity of dietary 1alpha-OH D3 or 1, 25-(OH)2 D3 is not caused by an increased specific activity of intestinal phytase.

Gan To Kagaku Ryoho, 1997 Sep, 24(11), 1512 - 8
{Morphological reversion of tumor cells by histone deacetylase inhibitors and radicicol}; Yoshida M et al.; Trichostatins and trapoxins, structurally unrelated microbial metabolites, are specific inhibitors of histone deacetylases . Radicicol inhibits Src family protein-tyrosine kinases . Recently, these agents were found to induce morphological reversion and enhanced expression of gelsolin, an actin regulatory protein, in a variety of transformed cells . Microinjection of an anti-gelsolin antibody that neutralizes the gelsolin function caused inhibition of the morphological change, suggesting that gelsolin expression is associated with the suppression of transformation.

Gan To Kagaku Ryoho, 1997 Sep, 24(11), 1477 - 85
{Antineoplastic glycoproteins in marine invertebrates}; Yamazaki M et al.; We searched marine invertebrates for new host defence molecules . We found several new cytolytic factors in Arthropoda and Mollusca . Especially, sea hares were revealed to have strong antitumor glycoproteins . These novel glycoproteins were purified to apparent homogeneity from Aplysia kurodai and Dolabella auricularia, and designated aplysianins and dolabellanins, respectively . The isolated glycoproteins lysed all the tumor cells tested, including TNF-resistant cells, but did not lyse normal white and red blood cells . The glycoproteins completely inhibited the synthesis of DNA and RNA by tumor cells within 2 hours and caused tumor lysis within 18 hours . Cytolysis was inhibited by the presence of N-acetylneuraminic acid, suggesting that the recognition of the sugar moiety is a key step in the tumor lysis by these antineoplastic glycoproteins from sea hares . These antitumor factors, except dolabellanins C and P, also showed anti-microbial activities . The sequence of the N-terminal part of dolabellanin A was similar to aplysianin A and achacin.

Genes Dev, 1997 Sep 15, 11(18), 2426 - 37
Mismatch repair protein MutL becomes limiting during stationary-phase mutation; Harris RS et al.; Postsynthesis mismatch repair is an important contributor to mutation avoidance and genomic stability in bacteria, yeast, and humans . Regulation of its activity would allow organisms to regulate their ability to evolve . That mismatch repair might be down-regulated in stationary-phase Escherichia coli was suggested by the sequence spectrum of some stationary-phase ("adaptive") mutations and by the observations that MutS and MutH levels decline during stationary phase . We report that overproduction of MutL inhibits mutation in stationary phase but not during growth . MutS overproduction has no such effect, and MutL overproduction does not prevent stationary-phase decline of either MutS or MutH . These results imply that MutS and MutH decline to levels appropriate for the decreased DNA synthesis in stationary phase, whereas functional MutL is limiting for mismatch repair specifically during stationary phase . Modulation of mutation rate and genetic stability in response to environmental or developmental cues, such as stationary phase and stress, could be important in evolution, development, microbial pathogenicity, and the origins of cancer.

Microbiology, 1997 Sep, 143 ( Pt 9), 2983 - 9
Ribosome analysis reveals prominent activity of an uncultured member of the class Actinobacteria in grassland soils; Felske A et al.; A 16S rRNA-based molecular ecological study was performed to search for dominant bacterial sequences in Drentse A grassland soils (The Netherlands) . In the first step, a library of 165 clones was generated from PCR-amplified 16S rDNA . By sequence comparison, clone DA079 and two other identical clones could be affiliated to a group of recently described uncultured Actinobacteria . This group contained 16S rDNA clone sequences obtained from different environments across the world . To determine whether such uncultured organisms were part of the physiologically active population in the soil, ribosomes were isolated from the environment and 16S rRNA was partially amplified via RT-PCR using conserved primers for members of the domain Bacteria . Subsequent sequence-specific separation by temperature-gradient gel electrophoresis (TGGE) generated fingerprints of the amplicons . Such community fingerprints were compared with the TGGE pattern of PCR-amplified rDNA of clone DA079 which was generated with the same set of primers . One of the dominant fingerprint bands matched with the band obtained from the actinobacterial clone . Southern blot hybridization with a probe made from clone DA079 confirmed sequence identity of clone and fingerprint band . This is the first report that a member of the novel actinobacterial group may play a physiologically active role in a native microbial community.

Am J Ind Med, 1997 Oct, 32(4), 423 - 32
Metalworking fluid-associated hypersensitivity pneumonitis: a workshop summary; Kreiss K et al.; A workshop discussing eight clusters of hypersensitivity pneumonitis in the automotive industry among metalworking fluid-exposed workers concluded that a risk exists for this granulomatous lung disease where water-based fluids are used and unusual microbial contaminants predominate . Strong candidates for microbial etiology are nontuberculous mycobacteria and fungi . Cases of hypersensitivity pneumonitis occur among cases with other work-related respiratory symptoms and chest diseases . Reversibility of disease has occurred in many cases with exposure cessation, allowing return to work to jobs without metalworking fluid exposures or, in some situations, to jobs without the same metalworking fluid exposures . Cases have been recognized with metalworking fluid exposures generally less than 0.5 mg/m3 . The workshop participants identified knowledge gaps regarding risk factors, exposure-response relationships, intervention efficacy, and natural history, as well as surveillance needs to define the extent of the problem in this industry . In the absence of answers to these questions, guidance for prevention is necessarily limited.

Am J Ind Med, 1997 Oct, 32(4), 325 - 31
Work-related asthma and respiratory symptoms among workers exposed to metal-working fluids; Rosenman KD et al.; The objective of this work was to determine whether the prevalence of respiratory symptoms differed among workers exposed to different types of metal-working fluids . As part of a mandatory surveillance system for occupational illness, from 1988-1994, the Michigan Department of Public Health received, 86 occupational disease reports of work-related asthma secondary to exposure to metal-working fluids . As part of a public health program, follow-up industrial hygiene inspections, including medical interviews of the workforce, were performed at companies where the reported cases had become ill . Metal-working fluids were the second most common cause of work-related asthma reported in the state . Most of the reports were from the automobile industry . Follow-up inspections were conducted at 37 facilities where the individuals with work-related asthma had worked . Seven hundred and fifty-five workers at these facilities were interviewed . Only one facility was above the allowable oil mist standard . Despite the exposure levels being within the legal limits, approximately 20% of the fellow workers of the reported cases had daily or weekly respiratory symptoms suggestive of work-related asthma . Workers exposed to emulsified, semisynthetic, or synthetic machining coolants were more likely to have chronic bronchitis; to have visited a doctor for shortness of breath; to have visited a doctor for a sinus problem; to be bothered at work by nasal stuffiness, runny nose, or sore throat; and to have an increased prevalence of respiratory symptoms consistent with work-related asthma, compared to workers exposed to mineral oil metal-working fluids . These findings were found in individuals who currently smoked, had never smoked or were ex-cigarette smokers . Further research to determine the chemical components or microbial contaminants responsible for these findings is needed.

Behring Inst Mitt, 1997 Feb, (98), 33 - 43
Routes of immunization and antigen delivery systems for optimal mucosal immune responses in humans; Mestecky J et al.; Numerous experiments performed in humans and animals have revealed that stimulation of mucosal lymphoid inductive sites such as intestinal Peyer's patches results in parallel immune responses manifested by the appearance of S-IgA antibodies in the external secretions of remote glands . However, recent experiments suggest that inductive sites associated with the upper respiratory tract, rectum, and perhaps genital tract may also function as sources of lymphoid cells that populate, with some selectivity, certain remote mucosal effector sites . Furthermore, antigen-specific IgA antibodies can be induced in certain secretions (e.g., female genital tract) not only by immunization in the vicinity of corresponding mucosal tissues (e.g., vagina and rectum) but also by oral and especially intranasal immunization . The ineffectiveness of simple delivery of soluble antigens to mucosal membranes for immunization has stimulated extensive studies of strategies for effective delivery systems that would (a) increase the antigen absorption, (b) prevent its degradation, and (c) skew the outcome of immunization to a desired goal (protective response to infectious diseases vs . tolerance; B vs . T cell responses; mucosal vs . systemic) . The induction of immune responses at a desired mucosal site can be accentuated with the use of a suitable antigen-delivery system including relevant bacterial or viral vectors, edible transgenic plants expressing microbial antigens, incorporation of antigens in biodegradable microspheres or liposomes, and linkage or coadministration of antigens with cholera toxin B subunit . However, only a few antigen-delivery systems extensively used in animal experimentation have been evaluated for their efficacy in humans . The combination of various immunization routes and the use of suitable antigen-delivery systems may accomplish an important task-the induction of mucosal immune responses at a location relevant to the site of entry of a given pathogen.

Biochim Biophys Acta, 1997 Aug 29, 1336(2), 211 - 7
Characterization of microbial cellulose from a high-producing mutagenized Acetobacter pasteurianus strain; Bertocchi C et al.; A wild-type Acetobacter pasteurianus was subjected to chemical mutagenesis for the induction and isolation of a cellulose overproducing strain . A mutagenized strain capable of synthesizing double amounts of cellulose compared to the wild type was obtained . Cellulose, both from the wild-type and the mutagenized strain, was extracted and purified for chemical characterization and investigation of its physico-chemical properties . The comparison of the two microbial polysaccharides shows that the putative mutation of A . pasteurianus strain had no effect on some cellulose features such as chemical structure, polymorphic form, crystallinity.

EMBO J, 1997 Aug 15, 16(16), 4817 - 25
Random mutagenesis reveals a region important for gating of the yeast K+ channel Ykc1; Loukin SH et al.; YKC1 (TOK1, DUK1, YORK) encodes the outwardly rectifying K+ channel of the yeast plasma membrane . Non-targeted mutations of YKC1 were isolated by their ability to completely block proliferation when expressed in yeast . All such mutations examined occurred near the cytoplasmic ends of the transmembrane segments following either of the duplicated P loops, which we termed the 'post-P loop' (PP) regions . These PP mutations specifically caused marked defects in the 'C1' states, a set of interrelated closed states that Ykc1 enters and exits at rates of tens to hundreds of milliseconds . These results indicate that the Ykc1 PP region plays a role in determining closed state conformations and that non-targeted mutagenesis and microbial selection can be a valuable tool for probing structure-function relationships of ion channels.

Med Trop (Mars), 1997, 57(2), 202 - 5
{Aspects of blood transfusion in Djibouti}; Massenet D et al.; Blood transfusion in Djibouti is organized with reference to relevant French regulation and the recommendations of the World Health Organization . The system is basically family donor system operating on the principle of one tested unit of blood for every two untested units donated . Spontaneous donations mainly from the police and army personnel account for only 20% of the 2500 units collected each year . The principle blood products are adult whole blood, adult red cells, and fresh frozen plasma . Products are distributed after viral and microbial testing for infectious disease . Overall the percentage of blood products that are not released due to detection of infectious agents is 17.5% . This rate is well correlated with the incidence of hepatitis B (15.5%), HIV infection (3.4%), hepatitis C (1.5%) and syphilis (0.4%) in Djibouti . The greatest demand for whole blood comes from medical departments where indigent people are treated for anemia due to dietary deficiency . Contamination by HIV present at undetectable levels at the time of testing is a serious problem . Measures should be taken to prevent anemia due to dietary deficiency and develop the use of autologous transfusion.

J Anim Sci, 1997 Sep, 75(9), 2550 - 60
Amino acid and energy interrelationships in growing beef steers: I . The effect of level of feed intake on ruminal characteristics and intestinal amino acid flows; Ludden PA et al.; Five cannulated Holstein steers (538 +/- 35 kg) were used in a 4 x 4 Latin square design experiment with extra observations to examine the influence of level of feed intake on postruminal flow and intestinal disappearance of N and amino acids (AA) . Treatments consisted of a single diet fed at four levels of energy intake (1.5, 2.0, 2.5, and 3.0 times NEm requirement) . The diet was formulated on a DM basis to contain 13.25% CP using cracked corn (56.1%), soybean hulls (18%), cottonseed hulls (15%), soybean oil (4.25%), and corn gluten meal (5.6%) . Increasing feed intake linearly increased (P < .0001) the quantity of OM truly digested in the stomach but tended to decrease (P = .11) OM digestion as a percentage of intake . Level of feed intake had no effect (P > .10) on ruminal pH, NH3 N, or peptide concentration or on particulate and fluid passage rates . However, total VFA concentration increased linearly (P < .0001) and the acetate: propionate ratio decreased linearly (P < .0001) as feed intake increased . Flows of microbial and nonmicrobial N at the duodenum linearly increased (P < .002) with increasing intake but did not differ (P > .10) as a percentage of intake . Level of feed intake did not affect (P > .10) microbial efficiency, N disappearance from the small intestine, or total tract N digestibility . With the exception of tryptophan, flows of all individual AA increased linearly (P < .01) with increasing intake . As a percentage of duodenal flow, AA digestion in the small intestine did not differ (P > .10), leading to a linear increase (P < .10) in the net quantity of individual (with the exception of tryptophan) and total AA disappearing from the small intestine as feed intake increased . Likewise, the profile of AA (except tryptophan) disappearing from the small intestine was unaffected (P > .10) by level of feed intake . When compared with predicted requirements for a 227-kg growing beef steer, Arg, Met, His, and Lys were suggested to be the most limiting AA for growth when this diet is fed . We conclude that altering energy intake by restricting intake of a single diet has only minor effects on the profile of digestible AA or other nutrients presented to the animal.

Histol Histopathol, 1997 Oct, 12(4), 1027 - 38
When intracellular pathogens invade the frontiers of cell biology and immunology; Pizarro-Cerda J et al.; Cellular microbiology has recently been described as a new discipline emerging at the interface between cell biology and microbiology (Cossart et al., 1996) . Many microbial pathogens can enter eukaryotic cells and live intracellularly either inside vacuoles or in the cytoplasm . The different steps during the invasion process are on the way of being dissected at the molecular level revealing new insights in basic cellular functions . Indeed, bacterial pathogenesis can help us to better understand the dynamics of cell cytoskeleton, intracellular membrane traffic and signal transduction events . The recent advancements in the field of microbial pathogenesis are creating a new cross-talk between cell biologists, microbiologists and immunologists . In this review, the different strategies used by several pathogens are presented and the mechanisms elaborated by host cells from the immune system to eliminate the parasites discussed.

Immunology, 1997 Jul, 91(3), 421 - 9
Regulation of HLA class I and II expression by interferons and influenza A virus in human peripheral blood mononuclear cells; Keskinen P et al.; HLA class I and II molecules play a central role in regulating host immune responses against microbial infections because they present foreign antigens to CD8+ and CD4+ T lymphocytes, respectively . Many cytokines, especially interferons (IFN), are known to upregulate human leucocyte antigen (HLA) class I and II gene expression, but the kinetics, expression levels and viral regulation of HLA genes in primary human cells have not been well documented . Stimulation of peripheral blood mononuclear cells (PBMC) with IFN-alpha and IFN-gamma resulted in a 1.5- to twofold increase in HLA class I and beta 2-microglobulin expression in lymphocytes and monocytes . Lymphocytes did not express any detectable HLA class II either basally or after IFN induction . In monocytes, instead, a high basal class II expression was found and it was further induced by IFN-alpha (up to twofold) and especially by IFN-gamma (up to fivefold) . In granulocyte-macrophage colony-stimulating factor (GM-CSF) differentiated human macrophages, basal HLA class I and II protein expression levels were high but IFN-gamma stimulation was able to further enhance their expression . Accordingly, class I and II mRNA expression was elevated by IFN-gamma, whereas IFN-alpha practically had no effect on HLA class I mRNA levels . Influenza A virus infection of macrophages resulted in temporary increases in HLA class I, beta 2-microglobulin and class II antigen expression . Neutralization of virus-induced IFN production by antibodies against type I and II IFNs prevented the virus-induced upregulation of HLA antigens . At late times of infection, as analysed by steady-state mRNA expression, both HLA class I and II mRNA were strongly reduced . These results suggest that IFNs are important regulators of HLA genes and responsible for a temporary increase in HLA antigen expression during influenza A virus infection.

Immunology, 1997 Jul, 91(3), 399 - 405
T-cell epitopes recognized within the 65,000 MW hsp in patients with IgA nephropathy; Warr K et al.; IgA nephropathy (IgAN) is the commonest cause of glomerulonephritis and clinical exacerbation of IgAN is frequently associated with mucosal infection . T-cell receptor gamma delta (TCR gamma delta+) cells are increased in both the circulation and in renal biopsies of patients with progressive IgAN . We examined the hypothesis that specific peptides within the 65,000 MW heat-shock protein (hsp) might stimulate TCR gamma delta cells and play a part in the immunopathogenesis of IgAN . We studied T-cell proliferative responses stimulated by overlapping peptides derived from the sequence of mycobacterial 65,000 MW hsp . Three T-cell epitopes have been identified (peptides 51-65, 71-85 and 281-295) . The three peptides have a synergistic effect and they stimulate significantly higher proliferation of T cells in patients with IgAN than in disease or healthy controls . This response was inhibited by monoclonal antibodies (mAb) to TCR gamma delta+ and human leucocyte antigen (HLA) class I, but not by mAb to HLA class II . The involvement of TCR gamma delta+ cells was confirmed by up-regulation of the proportion of TCR gamma delta+ cells when stimulated with the three specific peptides . We suggest that IgAN might be associated with mucosal infection by a variety of micro-organisms and that peptides within the microbial hsp cross-react with the homologous human hsp which may stimulate TCR gamma delta+ cells and play a part in the pathogenesis of IgAN.

Nippon Rinsho, 1997 Sep, 55(9), 2374 - 7
{Abnormal agglutination by reducing surface charge of red cell membrane as source of error in ABO typing and actual cases of incompatible ABO blood transfusion due to various factors}; Okada K; T activation of red cells results from the effects of microbial sialidase catalysing the cleavage of sialic acid from red cell membrane . Abnormal agglutination may be induced when human-derived antiA,B antibodies containing antiT are used . By the using of mouse-derived antiA,B monoclonal antibodies this type of polyagglutination as source of error could be overcome . Most common cause of ABO mismatch is due to more simple technical or clerical error resulting in transfusion of the wrong blood to the recipient . Three such cases with non-fatal hemolytic transfusion reaction are described.

Biochem Biophys Res Commun, 1997 Sep 8, 238(1), 149 - 53
NKR-P1A protein, an activating receptor of rat natural killer cells, binds to the chitobiose core of uncompletely glycosylated N-linked glycans, and to linear chitooligomers; Bezouska K et al.; NKR-P1 represent a family of activating receptors in rodent natural killer cells related to C-type animal lectins . We identify here the elements involved in the reactivity of the major receptor of rat, NKR-P1A, with N-linked oligosaccharides of glycoproteins . Plate inhibition assays with isolated, structurally defined N-glycans as inhibitors of binding of NKR-P1A to GlcNAc16-BSA revealed that the removal of both the external sialic acids and the penultimate galactose residues resulted in attaining of significant inhibitory activities . Surprisingly, additional plate inhibition and glycoprotein overlay experiments brought evidence that the core chitobiose, depending on its substitution, can per se support the interaction with NKR-P1A . In a series of linear chitooligomers (n = 2-7), the inhibitory activities reached a maximum for the chitotetraose . The ability of NKR-P1 to recognize both the periphery and the core region of complex type oligosaccharides may define its dual specificity towards carbohydrate components of eukaryotic (e.g., tumor) cell surfaces, but also reflect an evolutionarily conserved reactivity with microbial saccharides important in immune recognition and signaling functions.

Electrophoresis, 1997 Aug, 18(8), 1347 - 60
Proteome studies of Saccharomyces cerevisiae: identification and characterization of abundant proteins; Garrels JI et al.; Two-dimensional (2-D) gel electrophoresis can now be coupled with protein identification techniques and genome sequence information for direct detection, identification, and characterization of large numbers of proteins from microbial organisms . 2-D electrophoresis, and new protein identification techniques such as amino acid composition, are proteome research techniques in that they allow direct characterization of many proteins at the same time . Another new tool important for yeast proteome research is the Yeast Protein Database (YPD), which provides the sequence-derived protein properties needed for spot identification and tabulations of the currently known properties of the yeast proteins . Studies presented here extend the yeast 2-D protein map to 169 identified spots based upon the recent completion of the yeast genome sequence, and they show that methods of spot identification based on predicted isoelectric point, predicted molecular mass, and determination of partial amino acid composition from radiolabeled gels are powerful enough for the identification of at least 80% of the spots representing abundant proteins . Comparison of proteins predicted by YPD to be detectable on 2-D gels based on calculated molecular mass, isoelectric point and codon bias (a predictor of abundance) with proteins identified in this study suggests that many glycoproteins and integral membrane proteins are missing from the 2-D gel patterns . Using the 2-D gel map and the information available in YDP, 2-D gel experiments were analyzed to characterize the yeast proteins associated with: (i) an environmental change (heat shock), (ii) a temperature-sensitive mutation (the prp2 mRNA splicing mutant), (iii) a mutation affecting post-translational modification (N-terminal acetylation), and (iv) a purified subcellular fraction (the ribosomal proteins) . The methods used here should allow future extension of these studies to many more proteins of the yeast proteome.

Antonie Van Leeuwenhoek, 1997 Aug, 72(2), 159 - 65
Prediction of lipid accumulation-degradation in oleaginous micro-organisms growing on vegetable oils; Aggelis G et al.; Oleaginous micro-organisms (yeasts, moulds), in culture media having the carbon source as limited factor, degrade reserve lipids and produce new biomass, after the onset of carbon exhaustion from the medium . In this paper the process of lipid accumulation-degradation in oleaginous micro-organisms, growing on a vegetable oil was simulated . The model was integrated with 4 different methods and the parameters were optimised with the least squares method . It was found that the degradation of endocellular carbon pool is a very slow process characterised, however, by a good yield in fat-free biomass . Low values of the specific growth rates of the fat-free microbial mass, both from consumption of extracellular and endocellular carbon pools, favourite the production of microbial lipid . The maximum of the specific rate of lipid accumulation is positively affected by the low values of the specific growth rate of the fat-free microbial mass from consumption of extracellular carbon pool, but remained unaffected by the specific growth rate of the fat-free microbial mass from consumption of endocellular carbon pool . On the other hand, lipid production and specific rate of lipid accumulation are positively influenced by the high values of the specific rate of storage lipid formation . In conclusion, this numerical model can be used in the laboratory as pilot for planing further experimental work.

Antonie Van Leeuwenhoek, 1997 Aug, 72(2), 127 - 34
Thiobacillus sp . W5, the dominant autotroph oxidizing sulfide to sulfur in a reactor for aerobic treatment of sulfidic wastes; Visser JM et al.; The floating filter technique was successfully adapted for the isolation of the dominant, chemolithoautotrophic, sulfide-oxidizing bacterium from a sulfur-producing reactor after conventional isolation techniques had failed . The inoculated polycarbonate filters, floating on mineral medium, were incubated under gaseous hydrogen sulfide at non-toxic levels . This technique gave 200-fold higher recoveries than conventional isolation techniques . Viable counts on the filters, making up 15% of the total count, appeared to be all of the same species . Chemostat cultures of the new isolate had a very high sulfur-forming capacity, converting almost all hydrogen sulfide in the medium to elemental sulfur under high sulfide loads (27.5 mmol l-1 h-1) and fully aerobic conditions . This behaviour closely resembled that of the microbial community in the sulfur-producing reactor . Moreover, similar protein patterns were obtained by electrophoresis of cell-free extracts from the isolate and the mixed culture . It has therefore been concluded that this isolate represents the dominant sulfide-oxidizing population in the reactor . The isolate has been shown to be a new Thiobacillus species, related to Thiobacillus neapolitanus . In view of the general confusion currently surrounding the taxonomy of the thiobacilli, a new species has not been formally created . Instead, the isolate has been given the working name Thiobacillus sp . W5.

Antonie Van Leeuwenhoek, 1997 Jul, 72(1), 21 - 8
Advances in soil microbial ecology and the biodiversity; Hattori T et al.; Recent studies on the colony formation of soil bacteria opened the way to categorize soil bacteria into colony forming curve (CFC) groups of different growth rates . A bacterial culture collection comprising organisms from every CFC group is called an ecocollection (EC) . Outlines of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were described . Phylogenetic studies by 16S rDNA sequencing showed a great diversity of culture strains of the ecocollections . A set of alternative concepts was proposed; the active and the quiescent forms of bacterial cells in soil . The former is able to be cultivated and thus counted by the plate method, while the latter is not unless it transforms into the former . Based on the results several points required for extensive cataloguing of soil bacteria were noted.

AORN J, 1997 Sep, 66(3), 464 - 70
Efficacy of clean v sterile surgical prep kits; Pearce BA et al.; The goal of preoperative skin preparation is to reduce the risk of postoperative wound infections . This study was designed to determine if a difference exists in the residual microbial flora on the skin of surgical patients who are prepped with clean versus sterile prep kits . The researchers randomly assigned 60 ambulatory surgery patients to two preoperative skin preparation groups (i.e., clean prep kits, sterile prep kits) and obtained cultures of the patients' surgical sites at three different times (i.e., before performing standard povidone-iodine scrub-and-paint skin preps, 10 minutes after the completion of the skin preps, immediately after skin closure) . They used repeated mixed factorial analyses of variance to compute the differences in residual microbial counts at the patients' surgical sites . There was no difference in the residual microbial skin flora in the patients prepped with clean or sterile skin prep kits . The study results have significant cost-saving implications for health care facilities and surgical patients.

Microbiol Mol Biol Rev, 1997 Sep, 61(3), 305 - 18
Microbial physiology and ecology of slow growth; Koch AL; The uptake capabilities of the cell have evolved to permit growth at very low external nutrient concentrations . How are these capabilities controlled when the substrate concentrations are not extremely low and the uptake systems could import substrate much more rapidly than the metabolic capabilities of the cell might be able to handle? To answer this question, earlier theories for the kinetics of uptake through the cell envelope and steady-state systems of metabolic enzymes are discussed and a computer simulation is presented . The problems to the cell of fluctuating levels of nutrient and too much substrate during continuous culture are discussed . Too much substrate can lead to oligotrophy, substrate-accelerated death, entry into the viable but not culturable state, and lactose killing . The relationship between uptake and growth is considered . Finally, too little substrate may lead to catastrophic attempts at mounting molecular syntheses that cannot be completed.

Appl Environ Microbiol, 1997 Sep, 63(9), 3614 - 21
Diverse uncultivated bacterial groups from soils of the arid southwestern United States that are present in many geographic regions; Kuske CR et al.; We have performed a phylogenetic survey of microbial species present in two soils from northern Arizona . Microbial DNA was purified directly from soil samples and subjected to PCR amplification with primers specific for bacterial 16S rRNA gene sequences (rDNAs) . Clone libraries from the two soils were constructed, and 60 clone inserts were partially sequenced . Phylogenetic analysis of these sequences revealed extensive diversity . Most of the analyzed sequences (64%) fell into five novel clusters having no known cultured members . Extensive analysis of 10 nearly full-length rDNAs from clones representative of the novel groups indicated that four of the five groups probably cluster into a large "supergroup" which is as distinct from currently recognized bacterial divisions as the latter are from each other . From this we postulate the existence of a major bacterial lineage, previously known only from a single cultured representative, whose diversity and ecology we are only beginning to explore . Analysis of our data and that from other rDNA sequence-based studies of soils from different geographic regions shows considerable overlap of sequence types . Taken together, these groups encompass most of the novel rDNA sequences recovered in each comparable analysis reported to date, despite large differences in soil types and geographic sources . Our results indicate that members of these new groups comprise a phylogenetically diverse, geographically widespread, and perhaps numerically important component of the soil microbiota.

Steroids, 1997 Aug-Sep, 62(8-9), 564 - 77
Biotransformations on steroid nucleus of bile acids; Bortolini O et al.; The bile acids in mammals are all derivatives of 5 beta-cholan-26-oic acid . They represent the major quantitative pathway by which cholesterol is metabolized in the body . This article covers the microbial and enzymatic transformations of free, saturated bile acids, that kept unaltered the C-24 cyclopentane-perhydrophenantrene nucleus . The bile acids that have been considered include the primary cholic and chenodeoxycholic acids, the secondary deoxycholic and lithocholic acids as well as the relevant dehydrocholic, ursocholic and ursodeoxycholic acids . Among the bile acid biotransformations, attention is paid to reactions that lead to pharmaceutically significant compounds . This is the case of 7 alpha-hydroxy epimerization of chenodeoxycholic acid to ursodeoxycholic acid, currently used for cholesterol galistone dissolution therapy and in the treatment of cholestatic liver diseases . Emphasis has placed on reporting reactions that may be of general interest and on the practical aspects of work in the field of biotransformations.

Int J Parasitol, 1997 Aug, 27(8), 883 - 97
Parasite sulphur amino acid metabolism; Walker J et al.; This paper reviews current knowledge regarding the metabolism of the sulphur-containing amino acids methionine and cysteine in parasitic protozoa and helminths . Particular emphasis is placed on the unusual aspects of parasite biochemistry which may present targets for rational design of antiparasite drugs . In general, the basic pathways of sulphur amino acid metabolism in most parasites resemble those of their mammalian hosts, since the enzymes involved in (a) the methionine cycle and S-adenosylmethionine metabolism, (b) the trans-sulphuration sequence, (c) the transminative catabolism of methionine, (d) the oxidative catabolism of cysteine and (e) glutathione synthesis have been demonstrated variously in several helminth and protozoan species . Despite these common pathways, there also exist numerous differences between parasite and mammalian metabolism . Some of these differences are relatively subtle . For example, the biochemical properties (and primary amino acid structures) of certain parasite methionine cycle enzymes and S-adenosylmethionine decarboxylases differ from those of the corresponding mammalian enzymes, and nematodes and trichomonads possess a novel, non-mammalian form of the trans-sulphuration enzyme cystathionine beta-synthase . The most profound differences between parasite and mammalian biochemistry relate to a number of unusual enzymes and thiol metabolites found in parasitic protozoa . In certain protozoa the pathway for methionine recycling from 5'-methylthioadenosine differs markedly from the mammalian route, and involves 2 exclusively microbial enzymes . Trypanosomatid protozoa contain the non-mammalian antioxidant thiol compounds ovothiol A and trypanothione, together with unique trypanothione-linked enzymes . Specific anaerobic protozoa possess another exclusively microbial enzyme, methionine gamma-lyase, which catabolises methionine (and homocysteine); the physiological significance of these non-mammalian activities is not fully understood . These unusual features offer opportunities for chemotherapeutic exploitation, and in some cases represent metabolic similarities with bacteria . Additionally, some anaerobic protozoa contain unidentified thiols and this implies the presence of further unusual enzymes/pathways in these organisms . So far, no truly unique targets for chemotherapy have been found in helminth sulphur amino acid metabolism, and to some degree this reflects the relative lack of detailed study in the area.

J Med Microbiol, 1997 Sep, 46(9), 757 - 62
A comparison of methods of phenotypic and genotypic fingerprinting of Exophiala dermatitidis isolated from sputum samples of patients with cystic fibrosis; Rath PM et al.; Phenotypic and genotypic characteristics of 11 strains of Exophiala dermatitidis were investigated . Ten strains (including three reference strains) were isolated from sputum samples of six patients with cystic fibrosis (CF) in Germany, and one reference strain was isolated from a patient with phaeohyphomycosis in Japan . The strains showed differences in their ability to assimilate sorbitol, palatinose, rhamnose, gluconate and melezitose, leading to the differentiation of seven auxotypes . The IC30 of amphotericin B, and ketoconazole and itraconazole, respectively, indicated susceptibility, whereas the IC30 of fluconazole and 5-fluorocytosine indicated resistance in all strains . Protein patterns in SDS-PAGE revealed no major differences . The glycoconjugate patterns distinguished the Japanese strain from the other strains . Cluster analysis of whole-cell fatty acid methyl ester (FAME) profiles with the Microbial Identification System (MIS) revealed two major clusters separating a reference strain and the Japanese strain from the other strains . Analysis of patterns resulting from random amplification of polymorphic DNA (RAPD) with two arbitrary primers showed four genotypes . Comparison of the results revealed no agreement between the different fingerprinting methods, except the separation of the Japanese strain from the European CF strains . As the results of assimilation tests seem to vary between different laboratories, the analysis of FAME profiles and RAPD analysis are recommended for typing E . dermatitidis.

Br J Ophthalmol, 1997 Jul, 81(7), 537 - 40
Corneal infiltration after recurrent corneal epithelial erosion; Ionides AC et al.; AIMS: To describe the clinical features of patients with a history of recurrent corneal epithelial erosion who develop acute corneal infiltration . METHODS: The records were reviewed of patients who had previously been examined and treated for recurrent corneal epithelial erosion and who presented again with signs suggestive of a microbial keratitis . RESULTS: 11 patients were described; one patient presented with similar signs on two occasions . There was typically a paracentral epithelial defect > 2 mm in diameter with an associated stromal infiltrate and an intense anterior uveitis . Three patients had a hypopyon, and four developed a subepithelial ring infiltrate . Samples were taken for microscopy and bacterial culture, with a positive isolate from two of 12 episodes (16%) . Treatment with topical antibiotics and topical corticosteroid resulted in rapid re-epithelialisation and a reduction of inflammation . There was good visual outcome for all eyes, with a recurrence or symptoms of epithelial erosion in only one eye after a mean follow up period of 18 months . CONCLUSIONS: Corneal infiltrates are an uncommon complication of recurrent corneal epithelial erosion . Despite the intensity of the infiltration the majority are culture negative using established techniques . There is typically rapid resolution and a good visual outcome, with a tendency for the episode to mark the end of further symptoms of epithelial erosion.

Vet Clin North Am Equine Pract, 1997 Aug, 13(2), 303 - 15
Diseases and surgery of the cecum; Dabareiner RM et al.; The cecum is an important site of water and electrolyte absorption, as well as microbial digestion of soluble and insoluble carbohydrates . These functions of the cecum and ascending colon require that ingesta be mixed constantly and retained long enough to complete the digestion of cellulose . Parasites, changes in regional blood flow, diet, and various pharmacologic agents are associated with alterations in normal cecal motility patterns.

J Pediatr Gastroenterol Nutr, 1997 Sep, 25(3), 332 - 40
Spermine induces maturation of the immature intestinal immune system in neonatal mice; ter Steege JC et al.; BACKGROUND: In mice, immunological adaptation of the gut to microbial and nutritional antigens occurs at weaning in parallel with biochemical and morphological maturation . Because oral administration of spermine to neonatal rats has been shown to induce biochemical and morphological maturation, we investigated whether spermine also affects maturation of the mucosal immune system . METHODS: Swiss mice 7, 12, and 27 days old were given spermine orally (0.5 mumol/g body weight) during 3 days . Intestinal length was measured, and lactase and sucrase activities were determined . The phenotype of intraepithelial and lamina propria lymphocytes was assessed by FACS analysis using markers for CD3, TCR alpha beta, TCR gamma delta, CD4, CD8 alpha, CD8 beta, CD5, CD18, CD54, and CD49d . RESULTS: Similar to what occurs during natural development, spermine treatment of neonatal mice increased intestinal length, decreased lactase activity, and increased sucrase activity . The percentage of intraepithelial lymphocytes expressing TCR alpha beta, CD4, CD5, and CD54, as well as the levels of expression of these antigens, increased after spermine treatment on day 12, similarly to natural maturation . The increase in expression of CD3, TCR gamma delta, CD18, and CD49d did not reach statistical significance . No effect was observed on CD8 expression . The phenotype of lamina propria lymphocytes was not affected . Spermine administration to 7- and 27-day-old mice had no effect on the phenotype of either intraepithelial or lamina propria lymphocytes . CONCLUSIONS: Oral spermine administration to neonatal mice induced, in parallel with biochemical maturation, precocious maturation of the murine intestinal immune system and particularly affected differentiation of the intraepithelial lymphocyte population.

J Clin Invest, 1997 Sep 1, 100(5), 1114 - 22
Recognition of the immunodominant myelin basic protein peptide by autoantibodies and HLA-DR2-restricted T cell clones from multiple sclerosis patients . Identity of key contact residues in the B-cell and T-cell epitopes; Wucherpfennig KW et al.; Myelin basic protein (MBP) may be an important autoantigen in multiple sclerosis (MS), with the MBP(82-100) region being immunodominant for T cells and autoantibodies . The structural requirements for autoantibody recognition were compared to those previously defined for MBP-specific T cell clones . MBP autoantibodies were affinity-purified from central nervous system lesions of 11/12 postmortem cases studied . The MBP(83-97) peptide was immunodominant in all 11 cases since it inhibited autoantibody binding to MBP > 95% . Residues contributing to autoantibody binding were located in a 10-amino acid segment (V86-T95) that also contained the MHC/T cell receptor contact residues of the T cell epitope . In the epitope center, the same residues were important for antibody binding and T cell recognition . Based on the antibody-binding motif, microbial peptides were identified that were bound by purified autoantibodies . Autoantibody binding of microbial peptides required sequence identity at four or five contiguous residues in the epitope center . Microbial peptides previously found to activate T cell clones did not have such obvious homology to MBP since sequence identity was not required at MHC contacts . The similar fine specificity of B cells and T cells may be useful for tolerance induction to MBP in MS.

J Environ Sci Health B, 1997 Sep, 32(5), 599 - 620
Enhanced degradation of deethylatrazine in an atrazine-history soil of Iowa; Arthur EL et al.; The degradation of deethylatrazine (DEA), a major metabolite of atrazine, was studied by using radiotracers in soils with two different atrazine histories . DEA degradation was enhanced in soils which had received long-term exposure to atrazine (atrazine-history soil) compared with soils that had not received long-term atrazine exposure (no-history soil) . After 60 days of incubation, mineralization of DEA to 14CO2 in the atrazine-history surface soil was twice that in the no-history surface soils, with 34% and 17% of the applied 14C-DEA as CO2, respectively . In surface soils, 25% of the applied 14C remained as DEA in the atrazine-history soil, compared with 35% in the no-history soil . Microbial plate counts indicated an increase in numbers of bacteria and fungi in soils incubated with DEA compared to control soils . No significant difference in total microbial respiration was seen among atrazine-history and no-history soils incubated with DEA, but DEA-treated soils had greater microbial respiration than untreated control soils after 6 days . A 14C-most-probable-number procedure was used to enumerate specific DEA degraders . A greater number of DEA degraders were indicated in atrazine-history subsurface soil compared with all other soils in this study (p < 0.05) . From this study, it appears that an increase in microbial activity contributes to decreased persistence and increased degradation of DEA in soils that have had long-term exposure to atrazine at field application rates, compared to soils with no long-term exposure . Decreased persistence of this major metabolite of atrazine in atrazine-history soils is important in that there will be less available for movement in surface runoffs.

Blood, 1997 Aug 15, 90(4), 1576 - 87
Anti-Sia-lb (anti-Gd) cold agglutinins bind the domain NeuNAc alpha2-3Gal in sialyl Lewis(x), sialyl Lewis(a), and related carbohydrates on nucleated cells and in soluble cancer-associated mucins; Gallart T et al.; Anti-Sia-lb (formerly anti-Gd) cold agglutinins (CAs) recognize sialylated carbohydrates on both adult and neonate red blood cells (RBCs) . RBC CA activity inhibition experiments reported here indicate that the domain NeuNAc alpha2-3Gal, as found in sialyllactose, synthetic sialyl(s) Lewis(Le)(x) and sLe(a), sialyllactosamine, sialyl-fucosyllactose, and nonfucosylated sLe(a), constitutes the minimal epitope for these CAs, implicating that these autoantibodies could be able to bind this domain in sLe(x) and sLe(a) and related carbohydrates expressed on nucleated cells and in soluble cancer-related mucins . The following data obtained with the previously characterized monoclonal IgMk anti-Sia-lb CA, GAS, show that this is the case . GAS epitope expression among leukocytes that lack sLe(a) parallels that of sLe(x) determinant as detected by mouse monoclonal antibodies (MoAbs), especially MoAb KM-93 . It is also found on epithelial malignant cells bearing both sLe(x) and sLe(a) . GAS epitope on these nucleated cells, (1) like that present on RBC, is abolished by sialidase, unaffected by proteases, and inhibited by sialyllactose; and (2) is overlapping and/or proximal to that recognized by anti-sLe(x) MoAb, CSLEX-1, and KM-93 . Moreover, CAGAS binds soluble cancer-associated mucins bearing sLe(x) and sLe(a) determinants . This binding is inhibited by sialyllactose and these mucins inhibit the RBC CA activity of CAGAS . The possible significance of anti-Sia-lb (anti-Gd) CAs as autoantibodies directed to carbohydrate ligands of host adhesion molecules that might be receptors of microbial adhesins of some CA-inducing pathogens is discussed.

JAMA, 1997 Aug 6, 278(5), 425 - 7
The threat of biological weapons . Prophylaxis and mitigation of psychological and social consequences; Holloway HC et al.; The microbial world is mysterious, threatening, and frightening to most people . The stressors associated with a biological terrorist attack could create high numbers of acute and potentially chronic psychiatric casualties who must be recognized, diagnosed, and treated to facilitate triage and medical care . Media communications, planning for quarantine and decontamination, and the role of community leaders are important to the mitigation of psychological consequences . Physicians will need to accurately diagnose anxiety, depression, bereavement, and organic brain syndromes to provide treatment, reassurance, and the relief of pain.

J Interferon Cytokine Res, 1997 Aug, 17(8), 489 - 99
Microbial superantigens stimulate T cells by the superantigen bridge and independently by a cytokine pathway; Rink L et al.; Superantigens cross-link the MHC II molecule on accessory cells with the Vbeta region of the T cell receptor (TCR) . In this study, we compared the capacity of established superantigens for inducing cytokine release . The experimental protocol was generated to answer the question whether all superantigen effects are transmitted by the MHC/TCR cross-linkage and induce mainly a T cell response . We found that TSST-1, ExFTA, and SEC3 differed from all other superantigens tested because they stimulated a stronger monokine release . T cell proliferation after challenge with these superantigens was mainly mediated by a cytokine pathway and not by the cross-linkage of MHC and TCR . For the other superantigens, we were able to demonstrate that major immunomodulatory effect is mediated by the superantigen bridge . With the exception of these three superantigens, the proliferative response of superantigens correlated with their Vbeta specificity . Interleukin-1 (IL-1) and IL-6 were induced in monocytes by all superantigens, whereas tumor necrosis factor-alpha (TNF-alpha) was induced in T cells and by some superantigens, also in monocytes . IL-2 was always induced by the superantigen bridge, whereas interferon-gamma (IFN-gamma) was also induced indirectly by monokines . Collectively, our results indicate that not all superantigens are suitable for investigating superantigen-specific effects, as they show indirect (mitogenic) side effects . Observations for an individual superantigen are, therefore, not transferable to all other superantigens.

Chem Biol, 1997 Aug, 4(8), 561 - 7
Protein templates for the biosynthesis of peptide antibiotics; Marahiel MA; Peptide synthetases of microbial origin can act as protein templates for the biosynthesis of unusual, often pharmacologically active, peptides of diverse structure and biological activity . Specific repeated modules in the synthetases each contain at least two distinct domains, required for substrate adenylation and thiolation, that define the sequence and length of the peptide product . The first crystal structure of an adenylation domain has provided insights into the mechanism of substrate recognition and activation.

J Mol Cell Cardiol, 1997 Aug, 29(8), 2245 - 51
Antibodies against stress proteins in sera of patients with dilated cardiomyopathy; Portig I et al.; The pathogenesis of dilated cardiomyopathy (DCM) is as yet unknown . However, it is widely believed that autoimmune mechanisms contribute to the manifestations of the disease . In sera of patients with dilated cardiomyopathy, antibodies against different antigens, including heat shock protein (hsp) 60, were found . Antibodies against other stress proteins have not yet been reported . The aim of this study, therefore, was to screen sera of patients with DCM for the presence of antibodies against the major stress proteins . Lysate of stressed human endothelial cells was used as antigenic substrate in 1- and 2-dimensional immunoblot, since this cell type has recently been shown to express the major stress proteins . Antibodies against hsp60, hsp70, and heat shock cognate protein (hsc) 70 were detected in sera of patients with dilated cardiomyopathy as compared to healthy controls . Interestingly, antibodies against hsp70 and hsc70 were found in sera of patients younger than 30 years significantly more often than in older individuals . A correlation between the presence of antibodies against stress proteins and disease activity, clinical status, or histological findings was not detected . These findings support the view that DCM might be a consequence of an infectious disease, because stress proteins are immunodominant antigens in microbial agents and antibodies against stress proteins were detected in sera of patients with infectious diseases . Whether these antibodies are of pathogenetic significance or may be used as a disease marker will have to be elucidated in future experiments.

Am J Physiol, 1997 Aug, 273(2 Pt 1), L417 - 26
Regulation of transferrin gene expression during lung development and injury; Yang F et al.; Transferrin (TF), the major iron-transporting protein in vertebrates, is mainly synthesized in the liver . Although its source in lung is unknown, TF is a major inhibitor for lipid peroxidation and microbial propagation in lung fluid, and iron-free TF has been shown in rabbits to decrease the severity of respiratory failure and to improve surfactant activity . This study shows that TF is produced and secreted by the lung . In baboons and humans . TF gene expression displays distinct temporal patterns in different lung cells as revealed by in situ hybridization . Although expression of TF mRNA in submucosal glands remains active during development and throughout adulthood, its level in airway epithelial increases with advancing gestational age, reaches its peak before birth, declines 6-12 mo after birth, and diminishes in the older adult . In premature baboons maintained on ventilatory support, expression of TF mRNA is suppressed in both airway epithelium and glands . TF production by airway epithelia before birth most likely prevents oxidative damage in the newborn period, and its loss during injury may allow further lung damage.

Am J Physiol, 1997 Aug, 273(2 Pt 1), G322 - 32
Human hepatocytes express an array of proinflammatory cytokines after agonist stimulation or bacterial invasion; Rowell DL et al.; Inflammatory cells infiltrate the liver in response to microbial infection or hepatic injury . To assess the potential role hepatocytes may play in initiating or amplifying the acute inflammatory response in the liver, we used three human hepatocyte cell lines and primary human hepatocyte cultures to characterize the repertoire of cytokines that can be expressed and regulated in hepatocytes in response to agonist stimulation or bacterial infection . As reported herein, a proinflammatory cytokine gene program that includes C-X-C and C-C chemokines {interleukin-8(IL-8), growth related (GRO)-alpha, GRO-beta, GRO-gamma, epithelial neutrophil activating peptide-78 (ENA-78), and RANTES} and the cytokines tumor necrosis factor-alpha (TNF-alpha) and macrophage colony stimulating factor was upregulated in human hepatocytes after stimulation with IL-1 alpha or TNF-alpha or bacterial invasion . In contrast, expression of hematopoietic/ lymphoid growth factors by the same cells was either down-regulated (erythropoietin and stem cell factor) or unchanged (IL-7 and IL-15) in response to the identical stimuli . Hepatocytes did not express cytokines that often are associated with the regulation of antigen-specific immune responses (IL-2, IL-4, IL-5, IL-10, IL-12p40, IL-13, and interferon-gamma) or genes for several other proinflammatory cytokines {IL-1 alpha, IL-6, monocyte chemotactic protein-1 (MCP-1), and MCP-3} or hematopoietic growth factors (granulocyte colony stimulating factor, granulocyte macrophage colony stimulating factor, IL-3, and IL-11) . Together, these studies suggest that hepatocytes can both initiate and amplify acute inflammatory responses in the liver through the regulated expression and secretion of a specific array of proinflammatory cytokines.

J Dairy Sci, 1997 Aug, 80(8), 1703 - 12
Effects of supplementation of energy or ruminally undegraded protein to lactating cows fed alfalfa hay or silage; Vagnoni DB et al.; Alfalfa was harvested as silage or hay and fed in two 12-wk trials with a 4 x 4 Latin square design that used 12 (trial 1) or 24 (trial 2) multiparous lactating cows (4 ruminally cannulated cows per trial) . Diets contained (dry matter basis) 75 or 50% alfalfa plus 24 of 40% high moisture corn (trial 1) or 50% alfalfa, 44 or 41% high moisture corn, with (3%) or without fish meal (trial 2) . Experiments were conducted to evaluate the responses of cows fed alfalfa hay or alfalfa silage diets to an increase in protein supply from microbial protein synthesis (trial 1) or from the supplementation of ruminally undegraded protein (RUP) (trial 2) . In trial 1, the increase in high moisture corn in the diet increased both milk protein and microbial crude protein yields (estimated from the excretion of purine derivatives) to a greater extent for the cows fed the alfalfa silage diets (170 and 337 g/d, respectively) than for the cows fed the alfalfa hay diets (100 and 100 g/d, respectively) . In trial 2, RUP supplementation (as fish meal) increased milk protein yield 100 g/d for cows fed alfalfa silage diets and 20 g/d for cows fed alfalfa hay diets . These results indicated that protein status was poorer and, thus, more responsive to absorbable protein from microbial protein (trial 1) or RUP (trial 2) for cows that consumed alfalfa conserved as silage versus those that consumed alfalfa conserved as hay.

J Cutan Pathol, 1997 Aug, 24(7), 416 - 24
The clinical and histomorphological features of pityriasis rubra pilaris . A comparative analysis with psoriasis; Magro CM et al.; Pityriasis rubra pilaris (PRP) is an idiopathic erythematous scaling eruption which can be difficult to distinguish from psoriasis . We explored the clinical features, including background medical illnesses and potential triggers in patients with PRP, and also its histomorphologic spectrum . Patients with PRP were selected by natural language search of dermatopathology databases containing 250,000 cases accessioned over a 3-year period . A detailed medical history was obtained on each patient via office chart review and patient interviews . We compared the histologic findings in skin biopsies from patients with PRP to those of biopsies matched for site and age from control patients with psoriasis . Certain aspects of the clinical presentations encountered in the study group patients have not been previously emphasized, including eruptions compatible with a vesiculobullous disorder in 4 patients . Several patients had evidence of underlying iatrogenic or systemic immune dysregulatory states and certain triggers could be isolated such as emotional stress and prior exposure to microbial pathogens . Histomorphologic features predictive of PRP included follicular plugging, an increased granular cell layer, and acantholysis . While seen in a minority of biopsies of PRP, morphologic discriminators supportive of a diagnosis of psoriasis included neutrophils in the parakeratotic scale crust, and dermal papillae capillary ectasia with vessels lying in direct apposition to the epidermis . Other morphologic features were encountered in biopsies of PRP which have received little emphasis in the dermatopathology literature, including epithelial atrophy, significant dermal inflammation, the presence of eosinophils and plasma cells within the inflammatory infiltrates, an abnormal granular cell layer, and epidermolytic hyperkeratosis, albeit none were statistically signficant predictors of PRP over psoriasis . Nevertheless, their identification emphasizes the varied histologic spectrum of PRP . The almost ubiquitous finding of acantholysis and the presence of an abnormal granular cell layer in many biopsies of PRP suggests that abnormal keratins or defects in the retinol signalling pathway may be of pathogenetic importance.

Curr Opin Biotechnol, 1997 Aug 1, 8(4), 411 - 6
Recombinant proteins from transgenic plants; Franken E et al.; Transgenic plants can express a wide variety of foreign genes and offer the opportunity of large-scale protein production in agricultural systems . The recombinant protein can serve both ex situ and in situ purposes . Due to significant progress in plant molecular biology, many different plant species can now be transformed and are even capable of producing very complex proteins such as antibodies or vaccines . Furthermore, recombinant proteins can mediate resistance against microbial pathogens, such as fungi or viruses, or protect transgenic plants from insect pests.

J Anim Sci, 1997 Aug, 75(8), 2129 - 38
The efficacy of Aspergillus niger phytase in rendering phytate phosphorus available for absorption in pigs is influenced by pig physiological status; Kemme PA et al.; We performed an experiment with 112 piglets, 32 growing-finishing pigs, and 12 sows during pregnancy and lactation to test the hypotheses that apparent total tract digestibilities of P and Ca as well as the efficacy of Aspergillus niger phytase in rendering phytate P available in pigs depend on pig physiological status . All pigs were fed diets with identical feedstuff composition either without or with added microbial phytase (Natuphos, 500 FTU/kg diet) . The diets contained 6.2 g Ca, 4.8 g total P, and 3.7 g phytate P per kilogram, and intrinsic phytase activity of 120 FTU/kg . The digestibility of P increased by 8.3 percentage units when BW of pigs increased from 30 to 60 kg and then remained stable until 100 kg . Pregnant sows had a lower efficiency of P absorption than piglets and growing-finishing pigs . During lactation, the efficiency of P absorption was 3.4 percentage units higher than during pregnancy but was still 6.6 percentage units lower than for growing-finishing pigs . The efficacy of the phytase in generating digestible P decreased in the order or lactating sows, growing-finishing pigs, sows at the end of pregnancy, piglets, and sows at midpregnancy; the average amounts of generated digestible P were 1.03, .83, .74, .66, and .32 g/kg diet, respectively . The addition of phytase to the diet raised apparent Ca digestibility in the piglets and growing-finishing pigs (by 4.6 and 4.0 percentage units, respectively) but not in the sows . We conclude that in the formulation of swine diets the amount of phytase to be added should be tailored to the target category.

Exp Cell Res, 1997 Aug 1, 234(2), 233 - 9
Induction of neurite outgrowth in PC12 cells by gamma-lactam-related compounds via Ras-MAP kinase signaling pathway independent mechanism; Yao R et al.; Rat pheochromocytoma cells, PC12 cells, undergo differentiation in response to nerve growth factor (NGF) . Although the Ras-MAP kinase signaling pathway has been shown to play a central role in the response to NGF, the precise mechanism which induces differentiation remains unclarified . Recently, several gamma-lactam-related microbial products were identified to induce neurite outgrowth in neuroblastoma cells . Therefore, we synthesized a series of gamma-lactam-related compounds and tested for their ability to induce neurite outgrowth in PC12 cells . We found that two compounds, MT-19 and MT-20, induced neurite outgrowth at concentrations as low as 1 microg/ml . MT-19 and MT-20 have an n-hexadecyl group and an n-dodecyl group, respectively, at the position N-1 of the gamma-lactam ring, and the modification of this group leads to partial or complete loss of activity . In addition, the modification of the methyl and hydroxyl group at C-5 leads to complete loss of activity, indicating a strict structure-activity relationship . Interestingly, MT-19 and MT-20 induced neurite outgrowth of PC12 cells which lack normal Ras function . Furthermore, these compounds did not induce MAP kinase activation, suggesting that MT-19 and MT-20 do not require the Ras-MAP kinase signaling pathway which is shown to be necessary and sufficient for NGF-induced neurite outgrowth . Consistent with this, none of the early- or late-response genes tested, which include fos, zif268, Nur77, vgf, and transin, was induced . However, the protein level of three neurofilaments was increased after the incubation with these compounds . Since the level of other cytoskeleton proteins including actin and tubulin remained constant, MT-19 and MT-20 specifically affected neurofilament synthesis and/or turnover . Taken together, these findings indicate that MT-19 and MT-20 induce neurite outgrowth by activating the downstream target of MAP kinase or by a novel mechanism which is distinct from the NGF-activated pathway.

Curr Biol, 1997 Aug 1, 7(8), R508 - 11
Antigen presentation: mixing oil and water; Porcelli SA et al.; Studies of the cellular immunology and protein structure of human and mouse CD1 proteins reveal these to be a family of antigen-presenting molecules that allow T cells to recognize lipid and glycolipid antigens of microbial pathogens.

Int J STD AIDS, 1997 Aug, 8(8), 489 - 94
A longitudinal study of the vaginal flora over a menstrual cycle; Keane FE et al.; Healthy female volunteers participated in an anonymous study to monitor vaginal flora by taking daily vaginal samples and making a smear for later Gram-staining, as well as recording information on genital symptoms, sexual activity, contraceptive and bathing practices . A modification of Spiegel's criteria was used to categorize the Gram-stained smears, an intermediate category between normal flora and bacterial vaginosis (BV) being recognized . Of the 22 volunteers who completed the study, one was excluded because of pregnancy . Of the remaining 21 women, 10 (48%) had a normal flora throughout the study, 4 (19%) had an abnormal flora throughout and 7 (33%) had a basically normal flora which underwent a change to either an intermediate flora in 5 women or fully developed BV in 2 of them . In 5 (71%) of these women the change occurred within the first 9 days of the cycle . Transient changes in the vaginal microbial flora occurred predominantly in the first part of the menstrual cycle which suggests that in some women hormonal changes could have a role in the pathogenesis of bacterial vaginosis.

Curr Eye Res, 1997 Aug, 16(8), 802 - 9
Harvest and storage of adult human retinal pigment epithelial sheets; Tezel TH et al.; PURPOSE: To describe a method for the harvesting and storing of intact viable sheets of adult human retinal pigment epithelial (RPE) cells . METHODS: Adult human RPE cells were harvested as intact sheets from 21 cadaver eyes, using the enzyme Dispase . The sheets were embedded in 50% gelatin containing 300 mM sucrose and stored at 4 degrees C . The viability of the cells, as well as their ability to proliferate in vitro, was studied for 96 hours after harvesting . Light microscopy (LM), transmission (TEM) and scanning electron microscopy (SEM) were performed to determine the integrity and ultrastructural features of the cells . Microbiologic culture of the harvested sheets was performed to exclude contamination . RESULTS: LM, TEM and SEM showed intact RPE cells with well-developed microvilli, basal infoldings and intercellular connections . The initial viability of intact RPE sheets was 86%, with a progressive decline in viability with increased storage time . Cells harvested within 24 hours after death maintained greater viability than those harvested after 24 hours (p < 0.05) . Harvested RPE cells were free of microbial contamination and rapidly proliferated when cultured in vitro . CONCLUSION: Intact sheets of adult human RPE can be isolated using the enzyme Dispase . The cells appeared suitable for retinal transplantation if harvested within 24 hours of death and maintained 82% viability for as long as 48 hours if stored at 4 degrees C.

Appl Environ Microbiol, 1997 Aug, 63(8), 3242 - 5
Phosphorus and bacterial growth in drinking water; Miettinen IT et al.; The availability of organic carbon is considered the key factor to regulate microbial regrowth in drinking water network . However, boreal regions (northern Europe, Russia, and North America) contain a large amount of organic carbon in forests and peatlands . Therefore, natural waters (lakes, rivers, and groundwater) in the northern hemisphere generally have a high content of organic carbon . We found that microbial growth in drinking water in Finland is highly regulated not only by organic carbon but also by the availability of phosphorus . Microbial growth increased up to a phosphate concentration of 10 micrograms of PO4-P liter-1 . Inorganic elements other than phosphorus did not affect microbial growth in drinking water . This observation offers novel possibilities to restrict microbial growth in water distribution systems by developing technologies to remove phosphorus efficiently from drinking water.

Appl Environ Microbiol, 1997 Aug, 63(8), 3233 - 41
Analysis of actinomycete communities by specific amplification of genes encoding 16S rRNA and gel-electrophoretic separation in denaturing gradients; Heuer H et al.; A group-specific primer, F243 (positions 226 to 243, Escherichia coli numbering), was developed by comparison of sequences of genes encoding 16S rRNA (16S rDNA) for the detection of actinomycetes in the environment with PCR and temperature or denaturing gradient gel electrophoresis (TGGE or DGGE, respectively) . The specificity of the forward primer in combination with different reverse ones was tested with genomic DNA from a variety of bacterial strains . Most actinomycetes investigated could be separated by TGGE and DGGE, with both techniques giving similar results . Two strategies were employed to study natural microbial communities . First, we used the selective amplification of actinomycete sequences (E . coli positions 226 to 528) for direct analysis of the products in denaturing gradients . Second, a nested PCR providing actinomycete-specific fragments (E . coli positions 226 to 1401) was used which served as template for a PCR when conserved primers were used . The products (E . coli positions 968 to 1401) of this indirect approach were then separated by use of gradient gels . Both approaches allowed detection of actinomycete communities in soil . The second strategy allowed the estimation of the relative abundance of actinomycetes within the bacterial community . Mixtures of PCR-derived 16S rDNA fragments were used as model communities consisting of five actinomycetes and five other bacterial species . Actinomycete products were obtained over a 100-fold dilution range of the actinomycete DNA in the model community by specific PCR; detection of the diluted actinomycete DNA was not possible when conserved primers were used . The methods tested for detection were applied to monitor actinomycete community changes in potato rhizosphere and to investigate actinomycete diversity in different soils.

Poult Sci, 1997 Aug, 76(8), 1172 - 7
Performance of commercial laying hens fed various phosphorus levels, with and without supplemental phytase; Gordon RW et al.; A 17-wk study was conducted to evaluate the effects of supplementing laying hen diets with a commercially produced microbial phytase . Hy-Line W-36 pullets (21 wk of age) were randomly allocated to 1 of 10 diets in a factorial arrangement of five levels of nonphytate phosphorus (0.1 to 0.5% NPP) and two levels of phytase (0 and 300 U/kg feed) . Dietary metabolizable energy, protein, and calcium were maintained at 2,816 kcal/kg, 16.6%, and 4%, respectively . Criteria evaluated included egg production, feed consumption, egg weight, egg specific gravity, mortality, and various bone quality parameters . Feeding 0.1% NPP without supplemental phytase decreased egg production (hen-housed) 8.1% over the entire study and 29.6% over the last 4 wk, relative to other diets without supplemental phytase . Similarly, feed consumption of hens fed 0.1% NPP without phytase decreased 5.8% over 17 wk and 13.0% over the last 4 wk . Egg production and feed consumption were maintained at the level of other treatments without phytase when the 0.1% NPP diet was supplemented with phytase (82.1% and 82.4 g per hen per d, respectively) . Egg weights and egg specific gravity decreased and mortality increased when hens consumed 0.1% NPP without phytase . Supplementing the 0.1% NPP diet with phytase completely corrected these adverse effects . No deficiency symptoms were observed in hens fed diets containing 0.2 to 0.5% NPP . Phytase supplementation of these diets gave no further improvements in performance.

Science, 1997 Aug 1, 277(5326), 696 - 9
Analysis of a chemical plant defense mechanism in grasses; Frey M et al.; In the Gramineae, the cyclic hydroxamic acids 2,4-dihydroxy-1, 4-benzoxazin-3-one (DIBOA) and 2,4-dihydroxy-7-methoxy-1, 4-benzoxazin-3-one (DIMBOA) form part of the defense against insects and microbial pathogens . Five genes, Bx1 through Bx5, are required for DIBOA biosynthesis in maize . The functions of these five genes, clustered on chromosome 4, were demonstrated in vitro . Bx1 encodes a tryptophan synthase alpha homolog that catalyzes the formation of indole for the production of secondary metabolites rather than tryptophan, thereby defining the branch point from primary to secondary metabolism . Bx2 through Bx5 encode cytochrome P450-dependent monooxygenases that catalyze four consecutive hydroxylations and one ring expansion to form the highly oxidized DIBOA.

Infect Immun, 1997 Aug, 65(8), 3317 - 27
Pathogenesis of tuberculosis in mice exposed to low and high doses of an environmental mycobacterial saprophyte before infection; Hernandez-Pando R et al.; Mycobacteria are ubiquitous in the environment, but they are not part of the normal human microbial flora . It has been suggested that variable contact with mycobacteria can influence susceptibility to mycobacterial pathogens and the efficacy of subsequent Mycobacterium bovis BCG vaccination . To test this, mice were immunized with high or low doses of an environmental saprophyte, M . vaccae, that is intensely immunogenic as an autoclaved preparation . Two months later, they received an intratracheal challenge with M . tuberculosis H37Rv . Recipients of a low Th1-inducing dose (10(7) organisms) were partially protected and maintained a high ratio of interleukin 2 (IL-2)-positive to IL-4-positive cells in the perivascular, peribronchial, and granulomatous areas of the lung, whereas in unimmunized controls the IL-4-positive cells increased markedly between days 21 and 28 . In contrast, recipients of the high dose (10(9) organisms), which primes Th2 as well as Th1 cytokine production, died more rapidly than unimmunized controls and showed massive pneumonia from day 7 . The ratio of IL-2-positive to IL-4-positive cells in all compartments of the lung rapidly fell to 1 by day 14 for these animals . These events correlated with cytokine mRNA profiles and with increases in the local toxicity of tumor necrosis factor alpha (TNF-alpha), demonstrable only when a major Th2 component was present . These data indicate that cross-reactive epitopes present in an environmental saprophyte can evoke either protective responses or responses that increase susceptibility to M . tuberculosis . The latter are associated with the presence of a Th2 component and increased sensitivity to TNF-alpha.

Infect Immun, 1997 Aug, 65(8), 3199 - 202
Activation of the interleukin-1beta precursor by Treponema denticola: a potential role in chronic inflammatory periodontal diseases; Beausejour A et al.; There are several indications suggesting that interleukin-1beta (IL-1beta) may play an important role in inflammatory periodontal diseases . We hypothesized that periodontal sites would represent a unique combination of both cellular sources of IL-1beta precursor (pro-IL-1beta) and microbial proteases and proposed that Treponema denticola, a suspected periodontal pathogen, would play a critical role in the inflammatory nature of adult chronic periodontitis by activating pro-IL-1beta . The aim of this study was thus to demonstrate the proteolytic cleavage and activation of the inactive precursor pro-IL-1beta by T . denticola . After incubation of bacterial cells with recombinant pro-IL-1beta, proteolytic cleavage was monitored by Western immunoblotting, and the biological activity of the digestion products was tested in a bioassay . We report here that T . denticola can cleave pro-IL-1beta to yield two fragments with molecular masses of 18 and 19 kDa . Cleavage products showed a dose-dependent biological activity in the thymocyte proliferation bioassay, and this activity was inhibited by anti-IL-1beta neutralizing antibodies . These results suggest that T . denticola may have a proinflammatory role in periodontal diseases.

Cell, 1997 Jul 25, 90(2), 303 - 13
A human endogenous retroviral superantigen as candidate autoimmune gene in type I diabetes; Conrad B et al.; Microbial superantigens (SAGs) have been implicated in the pathogenesis of human autoimmune diseases . Preferential expansion of the Vveta7 T cell receptor positive T cell subset in patients suffering from acute-onset type I diabetes has indicated the presence of a surface membrane-bound SAG . Here, we have isolated a novel mouse mammary tumor virus-related human endogenous retrovirus . We further show that the N-terminal moiety of the envelope gene encodes an MHC class II-dependent SAG . We propose that expression of this SAG, induced in extrapancreatic and professional antigen-presenting cells, leads to beta-cell destruction via the systemic activation of autoreactive T cells . The SAG encoded by this novel retrovirus thus constitutes a candidate autoimmune gene in type I diabetes.

Proc Natl Acad Sci U S A, 1997 Jul 22, 94(15), 8243 - 8
AtMRP1 gene of Arabidopsis encodes a glutathione S-conjugate pump: isolation and functional definition of a plant ATP-binding cassette transporter gene; Lu YP et al.; Because plants produce cytotoxic compounds to which they, themselves, are susceptible and are exposed to exogenous toxins (microbial products, allelochemicals, and agrochemicals), cell survival is contingent on mechanisms for detoxifying these agents . One detoxification mechanism is the glutathione S-transferase-catalyzed glutathionation of the toxin, or an activated derivative, and transport of the conjugate out of the cytosol . We show here that a transporter responsible for the removal of glutathione S-conjugates from the cytosol, a specific Mg2+-ATPase, is encoded by the AtMRP1 gene of Arabidopsis thaliana . The sequence of AtMRP1 and the transport capabilities of membranes prepared from yeast cells transformed with plasmid-borne AtMRP1 demonstrate that this gene encodes an ATP-binding cassette transporter competent in the transport of glutathione S-conjugates of xenobiotics and endogenous substances, including herbicides and anthocyanins.

Am J Health Syst Pharm, 1997 Jul 15, 54(14), 1619 - 22
Stability of sumatriptan succinate in extemporaneously prepared oral liquids; Fish DN et al.; The stability of sumatriptan succinate in extemporaneously prepared oral liquids was studied . Suspensions of sumatriptan (as the succinate salt) in Ora-Sweet, Ora-Sweet SF, and Syrpalta syrups (Paddock Laboratories and Humco Laboratory) were extemporaneously compounded to produce a sumatriptan concentration of 5 mg/mL . Each suspension was prepared in triplicate . The suspensions were stored at 4 degrees C in amber glass bottles for 60 days . Two 1-mL samples were removed from each bottle initially and on days 2, 7, 14, 21, 28, 35, and 60 . Sumatriptan concentrations were determined by high-performance liquid chromatography . The samples also underwent visual inspection and microbial testing . The mean concentration of sumatriptan in all suspensions remained above 90% of the initial concentration for up to 21 days . By day 28, the sumatriptan concentration of all suspensions had decreased to less than 90% of the initial concentration . None of the suspensions had microbial growth up to day 28, and there were no visible changes in the suspensions throughout the study period . Sumatriptan 5 mg/mL (as the succinate salt) in three oral suspensions was stable for up to 21 days when stored without light at 4 degrees C.

Biochem J, 1997 Jul 15, 325 ( Pt 2), 391 - 400
Asymmetry adjacent to the collagen-like domain in rat liver mannose-binding protein; Wallis R et al.; Rat liver mannose-binding protein (MBP-C) is the smallest known member of the collectin family of animal lectins, many of which are involved in defence against microbial pathogens . It consists of an N-terminal collagen-like domain linked to C-terminal carbohydrate-recognition domains . MBP-C, overproduced in Chinese-hamster ovary cells, is post-translationally modified and processed in a manner similar to the native lectin . Analytical ultracentrifugation experiments indicate that MBP-C is trimeric, with a weight-averaged molecular mass of approx . 77 kDa . The rate of sedimentation of MBP-C and its mobility on gel filtration suggest a highly elongated molecule . Anomalous behaviour on gel filtration due to this extended conformation may explain previous suggestions that MBP-C forms a higher oligomer . The polypeptide chains of the MBP-C trimer are linked by disulphide bonds between two cysteine residues at the N-terminal junction of the collagen-like domain . Analysis of an N-terminal tryptic fragment reveals that the disulphide bonding in MBP-C is heterogeneous and asymmetrical . These results indicate that assembly of MBP-C oligomers probably proceeds in a C- to N-terminal direction: trimerization at the C-terminus is followed by assembly of the collagenous domain and finally formation of N-terminal disulphide bonds . The relatively simple organization of MBP-C provides a template for understanding larger, more complex collectins.

J Immunol, 1997 Jul 15, 159(2), 964 - 9
Effect of an ectokinase inhibitor, K252b, on degranulation and Ca2+ signals of RBL-2H3 cells and human basophils; Teshima R et al.; We examined the effects of K252b, an ectoprotein kinase inhibitor of microbial origin, on the activation process of RBL-2H3 cells by cross-linking of IgE receptors by the endoplasmic reticulum Ca2+-ATPase inhibitor 2,5-di(tert-butyl)-1,4-hydroquinone or by the Ca2+ ionophore A23187 . Analysis of phosphorylation of ectoproteins following IgE receptor cross-linking revealed that K252b mainly inhibited the phosphorylation of a 130-kDa protein . The inhibitor simultaneously inhibited degranulation and the sustained increase in the cytosolic calcium ion concentration even after addition of Ag . In contrast, K252b did not inhibit the increase in degranulation and cytosolic calcium ion concentration caused by stimulation with 2,5-di(tert-butyl)-1,4-hydroquinone and A23187 . Permeation of K252b into RBL-2H3 cells, assessed by fluorescence intensity, was very low . K252b also inhibited degranulation caused by IgE receptor cross-linking in human basophils, but did not inhibit the degranulation caused by A23187 . Thus, our findings suggest that the effects of K252b may be mediated by outer surface-bound or -anchored K252b-sensitive molecules on RBL-2H3 cells and human basophils, and that the phosphorylation of ectoprotein may involve a transmembrane influx of Ca2+ by IgE receptor cross-linking.

J Immunol, 1997 Jul 15, 159(2), 554 - 64
The generation of MHC class I-associated peptides is only partially inhibited by proteasome inhibitors: involvement of nonproteasomal cytosolic proteases in antigen processing?
Vinitsky A, Anton LC, Snyder HL, Orlowski M, Bennink JR, Yewdell JW.
The proteasome is believed to participate in the generation of a large percentage of peptide ligands for MHC class I molecules . This conclusion is based largely on the activities of peptidyl aldehydes that block proteasome activity . We tested the ability of a panel of proteasome inhibitors to affect the generation of MHC class I binding peptides in mouse L929 cells . Included in the panel are peptidyl aldehydes and a microbial product, lactacystin, that blocks proteasome activity in a distinct and more specific manner . Contrary to expectations, proteasome inhibitors failed to block the generation of a large portion of high affinity peptides as inferred by measuring cell surface expression of newly synthesized MHC class I molecules . These findings were confirmed by examining the effects of the inhibitors on the presentation of individual antigenic determinants from endogenously synthesized or exogenously delivered influenza virus proteins . Presentation of peptides derived from exogenous basic polymerase 1, endogenous basic polymerase 1, and nonstructural-1 proteins was decreased by inhibitors in a manner consistent with proteasomal involvement . Presentation of peptides derived from endogenous nucleoprotein was not significantly affected by the proteasome inhibitors, while presentation of exogenous hemagglutinin and nucleoprotein was enhanced by the proteasome inhibitors . These data are consistent with the involvement of both proteasomes and nonproteasomal cytosolic proteases in the generation of a significant portion of MHC class I binding peptides.

Proc Natl Acad Sci U S A, 1997 Jul 8, 94(14), 7515 - 20
Proteasome regulation of activation-induced T cell death; Cui H et al.; Lactacystin, a microbial metabolite that inhibits protease activity only in the proteasome, was used to study the role of the proteasome in the activation-induced cell death (AICD) of T cells . Lactacystin induces DNA fragmentation and apoptosis in a T cell hybridoma (DO.11 . 10) in a dose-dependent manner . Between 1 and 10 microM, the mildly cytotoxic lactacystin inhibited the AICD of DO.11.10 cells cultured in anti-CD3-coated wells . Degradation of IkappaBbeta and the translocation of the NF-kappaB (p50/RelA) into the nucleus, which occurred at 1.5 hr after anti-CD3 activation, were inhibited by lactacystin . Lactacystin did not inhibit the expression of nuclear transcription factor Oct-1 . The activation-induced expression of the immediate-early gene, Nur77, and the T cell death genes, CD95 (Fas) and CD95 ligand (FasL), were inhibited . Functional expression of FasL cytotoxicity and the increase of cell surface Fas were also inhibited . Lactacystin must be added within 2 hr of activation to efficiently block AICD . In addition, lactacystin failed to inhibit the killing of DO.11.10 by FasL-expressing allo-specific cytotoxic effector cells . These observations strongly suggest a direct link between the proteasome-dependent degradation of IkappaBbeta and the AICD that occurs through activation of the FasL gene and up-regulation of the Fas gene.

Bioorg Med Chem, 1997 Jul, 5(7), 1369 - 80
Microbial biotransformations of a synthetic immunomodulating agent, HR325; Lacroix I et al.; The microbial biotransformation of HR325 {2-cyano-3-cyclopropyl-3-hydroxy-N-(4'-trifluoromethyl-3'-methylphenyl)- propenamide}, a synthetic immunomodulating agent, has been investigated in order to be compared with animal metabolism and to prepare some metabolites which are difficult to obtain by chemical methods . Several fungal strains are able to completely metabolize this drug . Mortierella isabellina NRRL 1757 only achieves a benzylic hydroxylation on the aromatic methyl group, affording in high yield the corresponding hydroxymethyl derivative . In addition, other strains, such as Cunninghamella elegans ATCC 26269 or Beauveria bassiana ATCC 7159 can cleave both cyclopropyl and cyano groups in a new unknown oxidative biochemical reaction, which can be mimicked by m-chloroperbenzoate oxidation . The resulting cyanohydrin is hydrolyzed and reduced to a primary alcohol . In B . bassiana, the final incubation product is a beta-4-O-methylglucoside derivative of this alcohol, and has been fully characterized by independent synthesis . The different metabolic patterns of HR325 in the three fungal strains are discussed, and a mechanistic hypothesis about the oxidative cleavage of the right part of the molecule is proposed . The production of microbial metabolites is compared to animal metabolism in terms of structure and efficiency.

J Biomater Appl, 1997 Jul, 12(1), 20 - 30
In vitro response of Escherichia coli to antibiotics and ultrasound at various insonation intensities; Williams RG et al.; Microbial infections on implanted medical devices are difficult to treat . Application of 70 kHz ultrasonic irradiation to gentamicin treatment greatly enhanced the action of the antibiotic in terms of reduced viable bacterial concentrations . Ultrasonic irradiation was carried out at various insonation intensities that were noninhibitory in the absence of antibiotic . Synergistic killing was observed to be a function of ultrasonic intensity . Greatest killing (approximately 5 log reduction in viable population) was realized at full intensity (4.5 W/cm2), and decreased with reductions in power density . At lowest intensity (10 mW/cm2), no significant acoustic enhanced killing was noted.

J Intraven Nurs, 1997 Jul-Aug, 20(4), 201 - 6
Impact of dressing materials on central venous catheter infection rates; Treston-Aurand J et al.; Transparent, semipermeable, polyurethane dressings have become widely accepted for dressing central venous catheter (CVC) insertion sites . However, there have been differing results in terms of their association with microbial growth under the dressing and the risk of subsequent CVC-associated infection . This study describes our positive experience in terms of the impact of a highly permeable transparent dressing on CVC-associated infection among patients at our facility.

J Ind Microbiol Biotechnol, 1997 Jul, 19(1), 71 - 6
Mapping epitopes of neutralizing monoclonal antibodies using phage random peptide libraries; Zhong G et al.; Identification of protective determinants from microbial proteins is a necessary step in the rational design of subunit vaccines . We have previously used a synthetic peptide scan (Pepscan) assay to map a panel of eight neutralizing monoclonal antibodies (mAb; designated as C1.1 to C1.8) to a common motif sequence from Chlamydia trachomatis . In the present study, five of the eight mAbs were used to screen phage random peptide libraries . mAbs C1.1 and C1.3 selected a motif sequence of G-L-X-N-D from a pIII-based phage random peptide library and a motif sequence of G-X-X-N-D from a pVIII-based random peptide library while mAbs C1.6 to C1.8 failed to select recognizable motifs from either of the phage libraries . However, C1.6 to C1.8 bound to the same motif sequence displayed on phage when the appropriate conformational constraints were imposed onto the motif sequence . Thus the specificity of the mAbs identified on Pepscan assays correlates with the mAbs' dependence on local epitope constraints displayed on the phage surface.

Int J Oral Maxillofac Implants, 1997 Jul-Aug, 12(4), 527 - 40
Microbial leakage and marginal fit of the implant-abutment interface; Jansen VK et al.; Two-stage implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues . These gaps between the components are inevitable, and their clinical significance has so far been mostly neglected by both manufacturers and clinicians . The aim of the study was to determine whether there is microbial leakage at the implant-abutment interface . Thirteen different implant-abutment combinations were subjected to an in vitro experiment, in which the penetration of bacteria (Escherichia coli) was observed for 10 assemblies of each type . All implant systems presented microbial leakage . When the Frialit-2 implant was supplied with a silicon washer, there were fewer cases of leakage . The width of the marginal gap between the prefabricated components, measured with a scanning electron microscope, was less than 10 microns in all systems.

Appl Microbiol Biotechnol, 1997 Jul, 48(1), 99 - 104
Effect of the addition of Peptostreptococcus productus ATCC35244 on the gastro-intestinal microbiota and its activity, as simulated in an in vitro simulator of the human gastro-intestinal tract; Nollet L et al.; Peptostreptococcus productus ATCC35244, a reductive acetogenic strain, was added daily over 9 successive days to the fourth vessel (ascending colon) of the SHIME, a six-stage reactor system simulating the in vivo continuous culture conditions of the human gastro-intestinal tract . Final numbers of organisms (cfu)/ml reactor contents (c) were attained such that log10c = 6.9 +/- 0.1 . The addition caused the CH4 production to decrease below the detection limit while total gas and CO2 production in the fifth (transverse colon) and sixth reactor (descending colon) were lowered and the acetic acid concentration was augmented . Ending the supplementation caused CH4 production to re-establish within 4 days, while CO2 production increased much more slowly . The concentration of acetic acid only started to decrease after 7 days . The results indicate that P . productus, upon regular administration, is able to compete with methanogens for H2 in the gastro-intestinal microbial ecosystem because of its reductive acetogenic character.

Nutrition, 1997 Jul-Aug, 13(7-8), 622 - 8
Clinical and laboratory evaluation of a closed enteral feeding system under cyclic feeding conditions: a microbial and cost evaluation; Moffitt SK et al.; Cyclic feeding schedules are now commonly used in conjunction with closed enteral feeding systems . Some manufacturers and clinicians have speculated that closed system cyclic feeding may promote formula contamination via retrograde movement of bacteria during the "no-flow" periods . Using both laboratory and clinical settings, our study evaluated whether retrograde bacterial movement under "no-flow" conditions results in contamination of closed system feeding containers . The clinical phase was conducted with 57 closed system feeding containers used to feed nursing home residents . In both laboratory and clinical testing there was no evidence of container contamination at 36-48 h, nor was there evidence of retrograde movement of bacteria beyond the drip chamber . Formula waste and costs were also analyzed using several 24- or 36-h hang time scenarios . Provided the appropriate container size is used, potential cost savings between $67 to $135 per patient per month may be achieved with the 36-h hang time scenarios . Retrograde movement of bacteria does not appear to be a source of closed system feeding container contamination in systems that incorporate a drip chamber . Using the appropriate size feeding container and systems with at least a 36-h hang time will result in significant cost savings.

J Pharm Biomed Anal, 1997 Jul, 15(11), 1765 - 74
Indirect enantiomeric separation of 2-arylpropionic acids and structurally related compounds by reversed phase HPLC; Thomason MJ et al.; A reversed-phase high-performance liquid chromatographic method, using an organic modifier-phosphate buffered mobile phase, for the determination of the enantiomeric composition of 2-arylpropionic acids and other structurally related compounds in microbial media is described . The method is based on the resolution of diastereoisomeric amides formed from the reaction of the arylpropionic acid with either (-)-(S)-alpha-methylbenzylamine or (-)-(S)-1-(naphthen-1-yl)ethylamine in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide HCl and 1-hydroxybenzotriazole and incorporating an internal standard . The addition of sodium pentanesulphonate to the mobile phase as an ion-pairing agent was necessary to remove unreacted amine to avoid rapid column deterioration . The method provides and efficient, rapid and reproducible means of monitoring the microbial chiral inversion of 2-arylpropionic acids and other structurally related molecules.

J Pediatr Oncol Nurs, 1997 Jul, 14(3), 164 - 74; quiz 175-7
Assessment and management of chemotherapy-induced mucositis in children; Kennedy L et al.; Oral mucositis is one of the most common side effects of cancer treatment . The oral mucosa is comprised of membranes of a high mitotic index with rapid epithelial turnover and maturation rates . This causes the mucosa to be vulnerable to the adverse effects of chemotherapy . Chemotherapy alters the integrity of the mucosa, the microbial flora which normally inhabit the oral cavity, salivary quantity and composition, as well as the epithelial maturation . As a result, the child receiving chemotherapy may experience significant pain, dysphagia, alteration in nutritional status, and risk of infection . Severe mucositis can also delay therapy that may compromise the child's treatment and chance for cure . Not all chemotherapy-induced mucositis can be prevented . However, with proper management, the severity and duration of oral complications can be minimized.

J Med Microbiol, 1997 Jul, 46(7), 535 - 9
Infection and coronary heart disease; Ellis RW; A large body of evidence exists that implicates a number of microbial agents in the pathogenesis of coronary heart disease (CHD) . This, if proven, may have far-reaching implications for the prevention and treatment of CHD and other atherosclerotic disease . The histopathology of atherosclerosis and its natural history suggest infectious causation at many points along the progression of disease, particularly with regard to CHD, and a number of pathogens have been the focus of study . Viral agents implicated include Coxsackie B4 virus, for which tenuous sero-epidemiological associations exist, and the Herpesviridae . The animal herpesvirus causing Marek's disease in chickens causes atherosclerotic lesions in these animals . Herpes simplex virus I and II have been found in aortic smooth muscle and produce changes in vitro in smooth muscle that are similar to those seen at the beginning of atherosclerosis and which may also explain some of the features of atherosclerotic complications . Cytomegalovirus is implicated more strongly sero-epidemiologically by in-vivo detection in atherosclerotic lesions and by its links with post-cardiac transplant vasculopathya syndrome similar to atherosclerosis . Bacteria have also been shown to have links with CHD . Chlamydia pneumoniae and Helicobacter pylori have both been associated sero-epidemiologically with CHD, and these findings have been consolidated by recent work showing their presence in atherosclerotic lesions in adults . Bacterial infections in general lead to many changes in lipid, thrombic and other acute-phase protein metabolism, and some of these changes occur with both C . pneumoniae and H . pylori infections . The ubiquity and similar epidemiological features to CHD of all these microbial pathogens make the resolution of the causative issue impossible by retrospective means . All that can be shown at present are a variety of weak and strong links, the significance of which can only be determined by large and perhaps lifetime prospective studies.

Semin Gastrointest Dis, 1997 Jul, 8(3), 124 - 41
The expanding genus of Helicobacter: pathogenic and zoonotic potential; Fox JG; The microbial flora of stomachs of humans and animals have been the focus of considerable research since the discovery that Helicobacter pylori in humans caused a variety of gastric diseases . Other Helicobacter species have now been isolated from the stomachs of various mammals, including dogs, cats, ferrets, pigs, monkeys, and cheetahs, all of which are associated with various degrees of gastritis in their hosts . Helicobacter species have also been isolated from the intestinal tracts of humans, animals, and birds . Helicobacter species have not only been isolated from intestines of mice but have, in addition, been isolated from diseased livers of inbred and outbred mice, and one of these, H hepaticus is linked to liver tumors . H canis and H pullorum isolated from dogs and chickens, respectively, have also been cultured from feces of diarrheic humans . H fennelliae and H cinaedi are two additional helicobacters primarily associated with lower bowel disease in immunocompromised humans . To date, there are at least 13 formally named species of the new genus, Helicobacter, the majority being proven or suspected gastrointestinal or hepatic pathogens . Several of these helicobacters have zoonotic potential as well . It is predicted that additional Helicobacter species will be identified, and they, too, may be important pathogens in humans and animals.

Am J Respir Crit Care Med, 1997 Jul, 156(1), 196 - 200
The value of routine microbial investigation in ventilator-associated pneumonia; Rello J et al.; The use of microbiologic investigations in routine clinical practice, their value in guiding antibiotic prescription, and their influence on outcome were prospectively studied in 113 consecutive adults who developed ventilator-associated pneumonia (VAP) . Blood cultures were performed in 78.7% of cases, protected specimen brushing in 95.5%, and bronchoalveolar lavage in only 45.1% . No causative agent was identified in 13 episodes (11.5%), and results of microbial tests directed a change in therapy in 43 (38.0%) . Bronchoscopic results revealed inadequate initial selection of antibiotic therapy in 27 cases (23.9%) and led to a change in antibiotic treatment . Inadequate initial selection was still associated with a significantly greater increase in related mortality than adequate initial therapy (37.0% versus 15.4%, p < 0.05), although the change in therapy permitted clinical resolution in 17 (62.9%) of these 27 episodes, and 10 patients were discharged alive . Bronchoscopic results also permitted the reduction of the antibiotic spectrum in seven episodes (6.1%) . This study suggests that in patients with VAP, bronchoscopic results are frequently associated with changes in antibiotic therapy . Nevertheless, our findings also emphasize the critical importance of an appropriate early antibiotic therapy.

J Bacteriol, 1997 Jul, 179(14), 4457 - 63
Depletion of pre-16S rRNA in starved Escherichia coli cells; Cangelosi GA et al.; Specific hybridization assays for intermediates in rRNA synthesis (pre-rRNA) may become useful for monitoring the growth activity of individual microbial species in complex natural systems . This possibility depends upon the assumption that rRNA processing in microbial cells continues after growth and pre-rRNA synthesis cease, resulting in drainage of the pre-rRNA pool . This is not the case in many eukaryotic cells, but less is known about the situation in bacteria . Therefore, we used DNA probes to measure steady-state cellular pre-16S rRNA pools during growth state transitions in Escherichia coli . Pre-16S rRNA became undetectable when cells entered the stationary phase on rich medium and was replenished upon restoration of favorable growth conditions . These fluctuations were of much greater magnitude than concurrent fluctuations in the mature 16S rRNA pool . The extent of pre-16S rRNA depletion depended upon the circumstances limiting growth . It was significantly more pronounced in carbon-energy-starved cells than in nitrogen-starved cells or in cells treated with energy uncouplers . In the presence of the transcriptional inhibitor rifampin, rates of pre-16S rRNA depletion in carbon-energy-starved cells and nitrogen-starved cells were similar, suggesting that the difference between these conditions resides primarily at the level of pre-rRNA synthesis . Chloramphenicol, which inhibits the final steps in rRNA maturation, halted pre-16S rRNA depletion under all conditions . The data show that E . coli cells continue to process pre-rRNA after growth and rrn operon transcription cease, leading to drainage of the pre-rRNA pool . This supports the feasibility of using pre-rRNA-targeted probes to monitor bacterial growth in natural systems, with the caveat that patterns of pre-rRNA depletion vary with the conditions limiting growth.

J Leukoc Biol, 1997 Jul, 62(1), 30 - 3
MCP-1 and CCR2 in HIV infection: regulation of agonist and receptor expression; Sozzani S et al.; Monocyte chemotactic protein-1 (MCP-1) interacts with the chemokine receptor CCR2 . Two CCR2 cDNAs have been described . Sequence analysis as well as Northern blotting and RNase protection with different probes revealed that the CCR2 gene is expressed in activated natural killer (NK) cells and mononuclear phagocytes as a predominant long transcript (3.4 kb) consisting of CCR2B followed by a novel sequence (X), corresponding to an intron in the genome, and by a CCR2A specific portion . The predominant long transcript is polyadenylated and present in the cytoplasm . We found that bacterial products and cytokines affect CCR2 expression . Interleukin-2 (IL-2) augmented CCR2 mRNA in monocytes and NK cells . The augmented migratory capacity of IL-2-activated versus resting NK cells was associated with increased CCR2 transcript levels . Lipopolysaccharide (LPS) and other microbial agents caused a rapid and drastic reduction of CCR2 mRNA levels . The rate of nuclear transcription of CCR2 was not affected by LPS, whereas the mRNA half life was reduced . These results suggest that regulation of receptor expression, in addition to agonist production, is probably a crucial point in the regulation of the chemokine system . Down-regulation of chemokine receptor expression may play a role in the modulation of HIV infection in macrophages by LPS . Levels of MCP-1 were markedly elevated in the cerebrospinal fluid (CSF) but not in blood of HIV-infected patients with cytomegalovirus (CMV) encephalitis . The CSF levels of MCP-1 in CMV encephalitis were markedly higher than those found in the CSF of HIV-infected patients with or without unrelated neurological diseases . IL-8, the prototype of C-X-C chemokines and RANTES and macrophage inflammatory protein-1 alpha (C-C chemokines) were not substantially increased in the liquor of CMV encephalitis patients . High levels of MCP-1 may underlie monocyte recruitment and tissue damage in CMV encephalitis and may represent a rapid and useful tool in the diagnostic armamentarium for neurological disorders associated with HIV.

South Med J, 1997 Jul, 90(7), 681 - 4
The addition of antibiotics to fibrin glue; Thompson DF et al.; Fibrin glue is composed of two separate solutions of fibrinogen and thrombin . When mixed together, these two solutions mimic the final stages of the clotting cascade to form a fibrin clot . Because the resulting fibrin patch is a good medium for microbial growth, the addition of antibiotics to one of the components of fibrin glue has been shown to reduce postoperative infections . Seventeen different antibiotics have been investigated in vitro . Of the 17, cefotaxime, mezlocillin, gentamicin, neomycin, and polymixin B, when added to fibrin glue, can decrease the rate of clot formation or the strength of the resultant fibrin clot . Further work is necessary to characterize the effect the addition of antibiotics has on the rate and strength of fibrin clotting and to determine what effect low systemic levels of antibiotics might have on antibiotic resistance patterns.

J Anim Sci, 1997 Jul, 75(7), 1974 - 82
Lysine deficiency in postweaned calves fed corn and corn gluten meal diets; Abe M et al.; Holstein bull calves (n = 36) weaned at 6 wk of age were used in six trials to examine the response of N balance to postruminal administration of lysine with or without methionine in postweaned calves receiving diets based on corn and corn gluten meal . Calves were younger than 3 mo of age in Trials 1 and 2 but older than 3 mo in Trials 4 to 6 . L-Lysine monohydrochloride was supplemented with or without DL-methionine twice daily through the reticular groove, except in Trial 4, in which N supplements were infused through duodenal cannulas . L-Glutamine was used as a nonspecific N source in every trial, and casein was a positive control in Trials 4 and 5 . When daily CP intake from the diet was 3.9 g/kg BW, lysine was limiting for calves less than 11 wk of age (Trials 1 and 2) but not limiting for calves greater than 12 wk of age (Trial 3) . No amino acid seemed to be limiting for calves greater than 20 wk of age (Trial 4) when daily CP intake was 4.1 g/kg BW, but lysine was limiting when CP intake was restricted to 3.0 g/kg BW when calves were more than 17 wk of age (Trial 5) . However, lysine was not limiting above 18 wk of age (Trial 6) when CP intake was increased to 3.8 g/kg BW by adding urea to the diet . Results suggest that lysine may be limiting for corn and corn gluten meal diets only when ruminal microbial protein synthesis is restricted.

J Anim Sci, 1997 Jul, 75(7), 1723 - 8
Influence of dietary sulfur level on growth performance and digestive function in feedlot cattle; Zinn RA et al.; Using ammonium sulfate, three levels of dietary S (.15, .20, and .25%, DM basis) were evaluated in a finishing trial with 108 yearling crossbred heifers (384 kg) . The basal diet contained (DM basis) 4% alfalfa hay, 6% sudangrass hay, 74% steam-flaked corn, 4% yellow grease, 6% cane molasses, and 6% protein-mineral supplement . Increasing dietary S decreased ADG (quadratic effect, P < .10), DMI (linear effect, P < .10), feed efficiency (quadratic effect, P < .10), diet NE (quadratic effect, P < .10), and longissimus muscle area (linear effect, P < .05) . Six Holstein steers (218 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of digestion . Treatment effects on ruminal and total tract digestion of OM and N were small (P > .10) . However, ruminal digestion of ADF and starch was slightly lower (quadratic effect, P < .10), and postruminal digestion of ADF and starch was correspondingly greater (quadratic effect, P < .05) with supplemental S . Dietary S level did not influence (P > .10) ruminal synthesis of microbial N . Increasing dietary S did not influence (P > .10) ruminal pH or lactic acid . Increasing S decreased molar proportions of acetate (quadratic effect, P < .10) and increased molar proportions of propionate (linear effect, P < .10) . We conclude that S in excess of .20% of dietary DM may have detrimental effects on growth performance and dietary NE . Excessive dietary S may also compromise carcass merit by decreasing longissimus muscle area.

Arch Microbiol, 1997 Jul, 168(1), 39 - 45
Rhodospira trueperi gen . nov., spec . nov., a new phototrophic Proteobacterium of the alpha group; Pfennig N et al.; A new phototrophic purple bacterium was isolated from a flat, laminated microbial mat in a salt marsh near Woods Hole, Mass., USA . The spiral-shaped bacterium was highly motile and had bipolar tufts of flagella and intracytoplasmic membranes of the vesicular type . The major photosynthetic pigments were identified as the carotenoid tetrahydrospirilloxanthin and bacteriochlorophyll b . The long wavelength in vivo absorption maximum of the bacteriochlorophyll was at 986 nm . The marine bacterium showed optimal growth in the presence of 2% NaCl . It utilized a number of organic substrates as carbon and energy sources and required vitamins and sulfide as a reduced sulfur source for growth . In the presence of sulfide, elemental sulfur globules were formed outside the cells . Elemental sulfur was not further oxidized to sulfate . The new isolate had a unique lipid and fatty acid composition, and according to the 16S rRNA gene sequence, it is most similar to Rhodospirillum rubrum . It is described as a new species and assigned to a new genus with the proposed name Rhodospira trueperi.

Arch Environ Health, 1997 Jul-Aug, 52(4), 281 - 5
Airborne (1-->3)-beta-D-glucan and airway disease in a day-care center before and after renovation; Rylander R; Changes in symptoms and airway responsiveness among persons who worked in a day-care center that had microbial growth problems were assessed before and after renovation . Before and after the building renovation, the investigators used the Limulus assay with (1-->3)-beta-D-glucan-specific lysate to measure airborne levels of (1-->3)-beta-D-glucan, a cell-wall component of molds . Airway responsiveness and subjective symptoms were measured among 14 female employees with a methacholine test and a standardized questionnaire . After the renovation, (1-->3)-beta-D-glucan-glucan levels decreased from 11.4 to 1.4 ng/m3 . The number of persons who had increased airway responsiveness decreased after the renovation . Two employees developed a classical allergy to cat and pollen during the observation period . Although the study included only a few subjects and was based on only one day-care center, the data suggest that (1-->3)-beta-D-glucan may be related to airways inflammation caused by indoor air pollution.

J Immunol, 1997 Jul 1, 159(1), 86 - 91
Selective expansion of Vgamma2-Vdelta7 TCR gammadelta cells in C57BL/6 mice is postnatal and extrathymic; Sperling AI et al.; Previous studies have shown that TCR-gammadelta cells expressing Vgamma2 region elements are selectively expanded in vivo in C57BL/6 (B6), but not DBA/2, mice . Genetic analysis demonstrated that the expansion of Vgamma2+ was linked to the TCR alphadelta loci, suggesting that a particular Vgamma-Vdelta pair may be necessary for the expansion . In the studies presented here, we find that the expanding TCR gammadelta cells in B6 mice express a Vgamma2+/Vdelta7+ TCR . The Vgamma2-Jgamma and Vdelta7-Ddelta-Jdelta junctional amino acid sequences of these cells display wide variation in length, suggesting that expansion is based on variable region usage and not junctional diversity . The kinetics and dynamics of Vgamma2+/Vdelta7+ T cell expression were studied to determine the biological basis of clonal expansion . Although expression of the Vgamma2+ cells in B6 and DBA/2 neonates was similar, Vgamma2+ cells in the B6 mice expanded fourfold by 4 wk of age, while the expression in DBA/2 mice remained constant . In addition, expansion of the Vgamma2+ cells occurred in athymic nude mice, suggesting that expansion was driven by extrathymic stimuli . Finally, B6 mice housed under germfree conditions expressed expanded levels of Vgamma2+ gammadelta T cells similar to their normally housed counterparts . Thus, expansion and diversification of Vgamma2+/Vdelta7+ T cells are postnatal extrathymic events that do not require microbial antigenic exposure.

J Virol, 1997 Jul, 71(7), 5423 - 31
Comprehensive quantification of herpes simplex virus latency at the single-cell level; Sawtell NM; To date, characterization of latently infected tissue with respect to the number of cells in the tissue harboring the viral genome and the number of viral genomes contained within individual latently infected cells has not been possible . This level of cellular quantification is a critical step in determining (i) viral or host cell factors which function in the establishment and maintenance of latency, (ii) the relationship between latency burden and reactivation, and (iii) the effectiveness of vaccines or antivirals in reducing or preventing the establishment of latent infections . Presented here is a novel approach for the quantitative analysis of nucleic acids within the individual cells comprising complex solid tissues . One unique feature is that the analysis reflects the nucleic acids within the individual cells as they were in the context of the intact tissue-hence the name CXA, for contextual analysis . Trigeminal ganglia latently infected with herpes simplex virus (HSV) were analyzed by CXA of viral DNA . Both the type and the number of cells harboring the viral genome as well as the number of viral genomes within the individual latently infected cells were determined . Here it is demonstrated that (i) the long-term repository of HSV-1 DNA in the ganglion is the neuron, (ii) the viral-genome copy number within individual latently infected neurons is variable, ranging over 3 orders of magnitude from <10 to >1,000, (iii) there is a direct correlation between increasing viral input titer and the number of neurons in which latency is established in the ganglion, (iv) increasing viral input titer results in more neurons with greater numbers of viral-genome copies, (v) treatment with acyclovir (ACV) during acute infection reduces the number of latently infected ganglionic neurons 20-fold, and (vi) ACV treatment results in uniformly low (<10)-copy-number latency . This report represents the first comprehensive quantification of HSV latency at the level of single cells . Beyond viral latency, CXA has the potential to advance many studies in which rare cellular events occur in the background of a complex solid tissue mass, including microbial pathogenesis, tumorigenesis, and analysis of gene transfer.

FEBS Lett, 1997 Jun 30, 410(2-3), 259 - 64
Post-transcriptional regulation of inducible nitric oxide synthase mRNA in murine macrophages by doxycycline and chemically modified tetracyclines; Amin AR et al.; Chemically modified tetracyclines {CMT-3 (IC50 approximately 6-13 microM = approximately 2.5-5 microg/ml) and CMT-8 (IC50 approximately 26 microM = 10 microg/ml), but not CMT-1, -2 or -5}, which lack anti-microbial activity, inhibited nitrite production in LPS-stimulated macrophages . Unlike competitive inhibitors of L-arginine which inhibited the specific activity of inducible nitric oxide synthase (iNOS) in cell-free extracts, CMTs exerted no such direct effect on the enzyme . CMTs could, however, be shown to inhibit both iNOS mRNA accumulation and protein expression in LPS-stimulated cells . Tetracyclines (doxycycline and CMT-3) unlike hydrocortisone had no significant effect on murine macrophages transfected with iNOS promoter (tagged to a luciferase reporter gene) in the presence of LPS . However, doxycycline and CMT-3 augmented iNOS mRNA degradation, in LPS-stimulated murine macrophages . These studies show a novel mechanism of action of tetracyclines which harbours properties to increase iNOS mRNA degradation and decrease iNOS protein expression and nitric oxide production in macrophages . This property of tetracyclines may have beneficial effects in the treatment of various diseases where excess nitric oxide has been implicated in the pathophysiology of these diseases.

J Med Chem, 1997 Jun 6, 40(12), 1886 - 93
Structural studies on bioactive compounds . 28 . Selective activity of triazenyl-substituted pyrimethamine derivatives against Pneumocystis carinii dihydrofolate reductase; Stevens MF et al.; Triazenyl-substituted pyrimethamine derivatives 10a-s have been prepared by coupling diazotized 2,4-diamino-5-(3-amino-4-chlorophenyl)-6-ethyl pyrimidine (1c) with a series of secondary amines in aqueous sodium carbonate solution . The triazenes which are stable and poorly soluble as free bases form more soluble, but unstable, salts with alkanesulfonic acids . The lead dimethyltriazene 2,4-diamino-5{4-chloro-3-(3,3-dimethyltriazen-1-yl)phenyl}-6-et hylpyrimidine (4a) forms a crystalline ethanesulfonic acid salt (solvated with 2-propanol), which is protonated at the pyrimidine N-1 position, as determined by X-ray crystallography . The ability of these new triazenes to inhibit Pneumocystis carinii dihydrofolate reductase in vitro has been compared to that of triazene 4a . The most potent and selective compound, 2,4-diamino-5-{3-{3-{2-(acetyloxy)ethyl}-3-benzyltriazen-1-y l}-4- chlorophenyl}-6-ethylpyrimidine (14a), has an IC50 value of 0.17 microM against the microbial enzyme and potentially useful selectivity (rat liver IC50/P . carinii IC50 = 114).

Int J Clin Pract, 1997 Jun, 51(4), 232 - 7
Immune modulation and sepsis; Karzai W et al.; The pathogenesis of sepsis involves not only microbial toxins but also activated host inflammatory mediators . Therefore, besides conventional antibiotic or surgical treatment of infection and supportive intensive therapy, modulating host inflammatory mediators as a conjunctive therapeutic option has been explored in the past decade . Although successful in animal models of sepsis, inhibiting host inflammatory response in human sepsis has failed to improve survival or otherwise show efficacy . Studies are needed which better describe the circumstances under which these therapies may ultimately prove successful.

Cytokines Cell Mol Ther, 1997 Jun, 3(2), 115 - 25
MHC-derived peptides and the CD4+ T-cell repertoire: implications for autoimmune disease; Baum H et al.; The receptor repertoire of peripheral CD4+ cells is primarily determined by selection processes in the thymus . These result in the positive selection of T cells whose receptors weakly recognize self-peptides restricted by class II self-MHC heterodimers . A majority of such self-peptide partial agonists are likely to be derived from self-MHC molecules . It is suggested that these thymically selected, weakly autoreactive T cells may subsequently be stimulated by peripheral exposure to microbially derived agonists that 'mimic' corresponding self-MHC peptides . In turn, 'molecular mimicry' between microbial agonists and tissue-specific self-peptides may lead to T-cell-mediated autoimmune disease . Hence such disease may reflect 'three-way mimicry' between peptides of respectively target tissue, pathogen and self-MHC (or other self-peptide dominantly presented in the thymus) . This hypothesis accounts for the role of MHC haplotype in determining susceptibility to (or protection from) autoimmune disease . Direct evidence is presented in favour of the model as applied to diseases such as rheumatoid arthritis, autoimmune uveitus and autoimmune diabetes . Strong circumstantial evidence, based primarily on sequence similarities, is also presented for other autoimmune diseases . However, it is noted that the statistics of database searches, and the lack of predictable correlation between sequence similarity and T-cell cross-reactivity, require that such evidence be substantiated by further direct experiment.

J Antibiot (Tokyo), 1997 Jun, 50(6), 484 - 9
Inhibitors of type-I interleukin-1 receptor from microbial metabolites; Stefanelli S et al.; We describe here the results of a screening program conducted to discover inhibitors of the type-I interleukin-1 receptor (IL-1RI) from samples of microbial origin . An innovative approach, based on automated, nonradioactive receptor binding assays has been employed . Specially prepared cell-free systems have allowed the use of high concentrations of microbial metabolites in the reaction mixtures with a low percentage of false positives . More than 30,000 microbial samples from different species of soil isolates have been tested and two interesting activities have been purified and characterized . One of these, isolated from Streptomyces sp . GE48009, was identified as niphimycin, an antifungal agent also known as scopafungin . Preliminary evidence suggests that this molecule and azalomycin F, a structural analogue, inhibit IL-IRI by virtue of their long-chain guanidinium moiety . The other activity, isolated from Aspergillus sp . GE49752, was identified as flavipin, a substituted o-phthalaldehyde.

Microbiologia, 1997 Jun, 13(2), 161 - 72
Extracellular bacterial mineralization within the context of geomicrobiology; Ben Omar N et al.; In the biosphere, bacteria can function as geochemical agents, promoting the dispersion, fractionation and/or concentration of matter . These processes, which are being more and more valued from the point of view of various scientific disciplines, have given rise to the field of geomicrobiology . At the same time, microbial processes resulting in the concentration of matter and thus inducing the formation of minerals, constitute an area of research of growing interest known as biomineralization . In this review a succinct summary of various aspects of both disciplines has been offered together with a more detailed review of those aspects related to extracellular bacterial mineralization . The significance of the role played by the metabolism of bacteria is discussed along with the results of recent research on the role of dead bacteria and bacterial remains that act as heterogeneous nuclei of crystallization . The role played by the membranes of bacteria has also been considered to be highly relevant, and a discussion concerning their possible value as models for both the study of more complex biomineralization processes as well as application in the field of biomimetic materials is put forward.

Prof Nurse, 1997 Jun, 12(9), 655 - 9
Immunocompromised patients and nutrition; Henry L; Most immunocompromised patients will have undergone bone marrow transplantation . These patients will require both nutritional support and some form of dietary restriction . Food restrictions used with patients undergoing BMT include a sterile diet, low-microbial diet or modified hospital diet . No empirical research exists on the relative benefits of each.

Vaccine, 1997 Jun, 15(8), 874 - 8
Nucleic acid vaccination with HIV regulatory genes: a combination of HIV-1 genes in separate plasmids induces strong immune responses; Hinkula J et al.; The concept of combining several genes in order to immunize against a microbial agent has been tested . We selected human immunodeficiency virus (HIV) genes that individually have been shown to mediate immune responses against HIV proteins . These proteins were the regulating genes/proteins of HIV-1 rev, tat and nef as well as structural genes for gp160 under the control of rev, and the capsid p24 represented by the larger precursor gene p37 . Two findings were of particular interest . The combination of these five gene constructs gave strong reactivity to all of them, compared with previous results using each one in single injections . The intranasal immunization route gave good mucosal reactivity by inducing IgG, IgA and T-cell proliferative responses.

Nahrung, 1997 Jun, 41(3), 170 - 5
Application potential for some sugar substitutes in some low energy and diabetic foods; Bakr AA; Preparation of acceptable low energy fiber enriched and diabetic jams, cakes and biscuits using different formulas of sucrose substitutes with the partial replacement of wheat flour with bran as a source of dietary fibre, was studied . Special care was paid to evaluate the nutritional plus keeping qualities and the potential effect of the most acceptable formulae from each food stuffs group on the blood glucose level in lean and obese diabetes mellitus patients . It was technologically possible to prepare acceptable, high nutritional diabetic and low energy apricot, guava and strawberry jams and jellies by combinations of sweeteners using xylitol (i.e . xylitol-sorbitol-aspartame and xylitol-fructose) . The attainment of a suitable texture may be more difficult in xylitol and sorbitol jams, therefore 0.2 g CaCl2 . 2H2O was added . Storage of these jams at 4 degrees C improved their keeping quality significantly (p < 0.05), where the microbial load was less than 20 cells per gram and the products were free from molds and yeasts . Also, high nutritional and acceptable cakes and biscuits for low energy supply and for diabetic subjects can be sweetened with low level of aspartame in combination with fructose, sorbitol and xylitol . Consumption of such low energic and diabetic food items reduces significantly (p < 0.05) the plasma glucose level in lean and obese diabetics . Addition of wheat bran in bakery products not only reduced both energy value of these foods and blood glucose, but it also improved peripheral insulin activity by its system modification.

Br J Nutr, 1997 Jun, 77(6), 911 - 21
The relationship between in vitro gas production, in vitro microbial biomass yield and 15N incorporation and its implications for the prediction of voluntary feed intake of roughages; Blummel M et al.; The relationship between in vitro gas production, concomitant in vitro apparent and true DM degradability has been examined in forty-two roughages . The partitioning of truly-degraded substrate between gas volume and microbial biomass yield and 15N incorporation into cells was also investigated . The relevance of this partitioning for the regulation of DM intake (DMI) was examined for fifty-four roughages . The results can be summarized as follows . In vitro gas production and in vitro apparent and true degradability are highly correlated (P < 0.0001), r being 0.96 and 0.95 respectively . There is an inverse relationship between in vitro gas production and microbial biomass yield (r--0.67, (P < 0.0001) and also 15N enrichment (P < 0.001) when the variables were related to a given unit of substrate truly degraded . Selecting roughages by in vitro gas production may well be a selection against maximum microbial yield and a combination of in vitro gas volume measurements with a complementary determination of the substrate truly degraded is proposed, to calculate a partitioning factor (PF) reflecting the variation of short-chain fatty acid production per unit substrate degraded . PF is calculated as the ratio, substrate truly degraded: gas produced by it . PF was highly significant (P < 0.0001) in DMI prediction when included in stepwise multiple correlations together with in vitro gas volume variables reflecting the extent and rate of gas production; 11% of the variation in DMI was accounted for by the PF . The total model, including extent and rate of gas production and the PF, accounted for 84% of the variation in DMI . Roughages producing proportionally less gas per unit substrate truly degraded had higher feed intakes.

Biol Chem, 1997 Jun, 378(6), 553 - 8
Ribonuclease T1 is active when both catalytic histidines are replaced by aspartate; Landt O et al.; The enzymatic activity of many ribonucleases (RNases) depends on two histidines, as in RNase A, or one histidine and/or glutamate, as in microbial RNases belonging to the T1 family . In RNase T1, substitution of either one or both of the two histidines at positions 40 and 92 by a variety of other amino acids reduces the activity more than 100-fold . However, the double variant His40-->Asp/His92-->Asp retains a significant residual enzymatic activity towards RNA and guanylyl-3',5'-cytidine, indicating that a pair of substituted side chains in these positions, both with acid functionality, can confer enzymatic activity . It was shown that the substitution of histidine with glutamate in the variant His40-->Glu yields an enzyme with drastically reduced activity and leads to inactivation in the His92-->Glu, His40-->Glu/His92-->Glu variants . For the variants where histidine is substituted with aspartate we found measurable activity from 1% (His40-->Asp) to 6% (His40-->Glu/His92-->Asp) towards RNA.

Int J Biol Macromol, 1997 Jun, 20(3), 221 - 31
Influence of substituent of direct dye having bisphenylenebis(azo) skeletal structure on structure of nascent cellulose produced by Acetobacter xylinum {I}: different influence of direct red 28, blue 1 and 15 on nascent structure; Kai A et al.; The difference of influence of a certain kind of direct dye on the structure of nascent microbial cellulose was examined, with Direct Red 28 have a biphenylenebis(azo) skeletal structure; Direct Blue 1 having two hydroxyl, two methoxy and two sulfonate groups more than Direct Red 28; and Direct Blue 15 whose sulfonate groups position are different compared to Direct Blue 1 . It became clear that the product in the presence of a direct dye (in particular, Direct Red 28) has the structure in which the dye molecule is included between the monolayer in the cellulose sheets corresponding to the (110) plane of microbial cellulose . On the other hand, the structure of the product in the presence of Direct Blue 1 and 15 contains conceived cellulose II structure which occurred due to be removal of dye during the rinsing process as a result of larger hydrophilicity than its affinity toward cellulose . Solid state 13C NMR and deuteration-IR measurements showed that the product in the presence of direct dye is in a noncrystalline state, although X-ray measurements indicated that they are in a crystalline state . These results support the inclusion of a dye between the (110) planes . Solid state 13C NMR and deuteration-IR reveal that the crystal structure of cellulose regenerated from the product in the presence of Direct Red 28 is similar to cellulose IVI, while that from each Direct Blue 1 and 15 product is cellulose II . The difference of the influence of the former and the latter on the nascent cellulose seemed to be caused mainly by the number of sulfonate groups, although the influence of hydroxyl and methoxy groups is not clear at present.

Ecotoxicol Environ Saf, 1997 Jun, 37(1), 97 - 102
Additivity in microbial toxicity of nonuniform mixtures of organic chemicals; Nirmalakhandan N et al.; Microbial toxicity of nonuniform mixtures of selected synthetic organic chemicals in several proportion is evaluated . Toxicity is quantified by the inhibition of oxygen uptake rate of a surrogate microbial text culture as measured by a respirometer . The joint toxic effects of the chemicals are analyzed for simple addition using toxic units (TU) and similarity parameters (lambda) . A new approach is proposed to assign acceptance limits to sigma(TU)i and lambda to account for experiment errors and variances . Based on this approach, the joint toxic effects of 16 chemicals evaluated in this study in 14 different mixtures were found to be simply additive . Predictions of component concentration based on simple additivity agreed with the measured values within an average factor of error of 1.4.

DNA Cell Biol, 1997 Jun, 16(6), 691 - 701
Cloning and expression of two human lysophosphatidic acid acyltransferase cDNAs that enhance cytokine-induced signaling responses in cells; West J et al.; Lysophosphatidic acid (LPA) and phosphatidic acid (PA) are two phospholipids involved in signal transduction and in lipid biosynthesis in cells . LPA acyltransferase (LPAAT), also known as 1-acyl sn-glycerol-3-phosphate acetyltransferase (EC 2.3.1.51), catalyzes the conversion of LPA to PA . In this study, we describe the isolation and characterization of two human cDNAs that encode proteins possessing LPAAT activities . These two proteins, designated here as LPAAT-alpha and LPAAT-beta, contain extensive sequence sequence similarities to microbial or plant LPAAT sequences . LPAAT-alpha mRNA was detected in all tissues with highest expression in skeletal muscle whereas LPAAT-beta was expressed predominantly in heart and liver tissues . Expression of these two cDNAs in an Escherichia coli strain with a mutated LPAAT gene (plsC) complements its growth defect and shifts the equilibrium of cellular lipid content from LPA to PA and other lipids . Overexpression of these two cDNAs in mammalian cells leads to increased LPAAT activity in cell-free extracts using an in vitro assay that measures the conversion of fluorescently labeled LPA to PA . This increase in LPAAT activity correlates with enhancement of transcription and synthesis of tumor necrosis factor-alpha and interleukin-6 from cells upon stimulation with interleukin-1beta, suggesting LPAAT overexpression may amplify cellular signaling responses from cytokines.

J Trauma, 1997 Jun, 42(6), 1006 - 10; discussion 1010-1
Incidence of bacteremia after burn wound manipulation in the early postburn period; Mozingo DW et al.; BACKGROUND: Transient bacteremia associated with burn wound manipulation is considered a frequent occurrence and is commonly cited as an indication for perioperative antibiotic prophylaxis in burn patients . METHODS: In a prospective clinical setting, blood cultures (BC) were obtained from 19 burn patients at the following intervals: 30 minutes before wound cleansing (WC) or wound excision (WE), 30 minutes after the start of WC or WE, hourly until procedure completion, and 1 hour after completion . Burn wound biopsy for histologic grading and microbial culture was performed after the first BC . RESULTS: Twenty-two WC and 20 WE episodes were evaluated by 67 and 76 BC sets, respectively . Patients had a mean age of 42.8 years and mean burn size of 50% of the body surface area . Three WC episodes (13.6%) and four WE procedures (20.0%) were associated with postprocedure bacteremia . Two patients had both preprocedure and postprocedure bacteremia later attributed to nonburn wound infections . Excluding these cases, the bacteremia rate was 12.5% (9.5% from WC and 15% from WE) . Wound biopsy culture and histologic analysis did not predict the occurrence of bacteremia . CONCLUSION: Current therapy is associated with a lesser incidence of burn wound manipulation-induced bacteremia than reported in prior series . The discordance between wound biopsy and BC results, the absence of positive histology, and the similarity of bacteremia occurrence rates with WC and WE confirm the effectiveness of current techniques of microbial control in burn wounds and question the need for perioperative antibiotic therapy in patients with burns involving less than 40% of the total body surface during the first 10 postburn days.

Semin Oncol, 1997 Jun, 24(3 Suppl 9), S9 - 70-S9-77
Interacting pathways of interferon signaling; Williams BR et al.; Interferons (IFNs) are important modifiers of biologic response in vertebrate cells . After IFNs are induced, in response to viral or microbial infections, the IFNs bind to specific receptors on the surface of target cells and cause rapid activation of IFN-stimulated genes . These genes mediate the different biologic effects of the IFNs . The molecular characterization of IFN-induced gene activation led to the discovery of the Jak-Stat signal transduction pathway, which is now known to be shared by many other cytokines, growth factors, and hormones . Protein phosphorylation plays a key role in the Jak-Stat pathway, which consists of a cascade of specific protein-protein interactions that culminate in protein-DNA engagement and specific transcription . Although responses in the signaling pathways to various IFN-alpha species have not been examined in detail, it is likely that subtle differences in receptor interaction between the various IFN-alpha species, whether derived from natural or synthetic genes, may produce an unexpected array of biologic effects and clinical responses.

J Periodontol, 1997 Jun, 68(6), 556 - 62
The effect of surface roughness on early in vivo plaque colonization on titanium; Rimondini L et al.; THE STUDY ASSESSES IN VIVO the surface roughness necessary to reduce plaque colonization on titanium after 24 hours . Three groups of 16 titanium disks were assigned to 3 different polishing groups (A, B, and C) . The roughness was evaluated with a laser profilometer and the morphology with a scanning electron microscope (SEM) . Eight volunteers were enrolled and two stents were applied in the mandibular posterior region of each . Each stent supported 3 disks, one per group . The volunteers suspended oral hygiene for 24 hours, after which the stents were removed; one was processed for evaluation of the adherent biomass and the other for SEM study . On each specimen a global area of 100 x 125 microns was examined with SEM . The area was composed of five 20 x 25 microns randomly selected fields . For each field the density of bacteria and the morphotypes were recorded . The data quoted for the global area are cumulative of those observed in the 20 x 25 microns fields . Group A had a significantly smoother surface than groups B and C . The adherent microbial biomass determination and SEM evaluation revealed that group A contained less bacteria than the roughest group . The bacterial population was composed of cocci in group A, and of cocci and short and long rods in groups B and C . We conclude that a titanium surface with Ra < or = 0.088 microns and Rz < or = 1.027 microns strongly inhibits accumulation and maturation of plaque at the 24-hour time period and that such smoothness can be achieved in transgingival and healing implant components.

J Appl Microbiol, 1997 Jun, 82(6), 689 - 94
Mycobiota in Portuguese 'normal' and 'green' cork throughout the manufacturing process of stoppers; Danesh P et al.; The compounds responsible for the so-called 'cork taint' include, among others, some microbial metabolites which can be produced by the microbial population colonizing the unprocessed cork and stoppers . This study was intended to obtain information on the mycobiota associated with Portuguese cork throughout the manufacturing process of stoppers . Samples of barks and stoppers of both 'normal' and 'green' cork were examined . Moulds were isolated from 'normal' and 'green' cork throughout the entire cork stopper manufacturing process . Yeasts were rarely detected in the corks . Fungal contamination was not detected in finished stoppers from the company under study.

J Dairy Sci, 1997 Jun, 80(6), 1143 - 9
Relationships between in situ protein degradability and grass developmental morphology; Mitchell RB et al.; The objective of this research was to determine the relationships between the morphological development and in situ ruminally degradable protein (RDP), ruminally undegradable protein (RUP), and microbial protein of two cool season grasses (intermediate wheatgrass and smooth bromegrass) and two warm season grasses (switchgrass and big bluestem) . The initial growth of grass tillers grown near Mead, Nebraska was clipped at ground level six times during the 1992 growing season and morphologically classified . Mean stage was calculated . Forage was ground to pass a 2-mm screen and was incubated in ruminally fistulated steers for 16 h . The RUP was adjusted for microbial protein and acid detergent insoluble N . The mean stage of cool season grasses was higher than that of warm season grasses throughout the growing season . The RDP decreased as plant maturity increased for all species . The RUP expressed as a percentage of crude protein for the cool season grasses was lower than that for warm season grasses . The RUP for intermediate wheatgrass, smooth bromegrass, and switchgrass remained constant across maturities, but RUP for big bluestem decreased as maturity increased . Microbial augmentation of RUP decreased as crude protein decreased in all species . The RUP corrected for acid detergent insoluble N and microbial protein was relatively constant across plant maturities . The quantification of RUP across a range of plant maturities provided information for incorporating RUP content of forage grasses into the diets of animals.

Nippon Rinsho, 1997 Jun, 55(6), 1370 - 6
{Molecular mimicry and mechanisms of autoantibody production}; Miyazawa M; Molecular mimicry is defined as similar structures shared by products of dissimilar genes . This review article discusses a possible role of molecular mimicry in the production of autoantibodies . Antibodies reactive with products of bacterial and viral genes sometime cross-react with normal cellular proteins . Sera from patients with systemic autoimmune diseases show crossreactivity with some bacterial and/or viral gene products at a significant frequency . Identification of the structures of antigenic epitopes recognized by disease-associated autoantibodies by expression cloning of autoantigen molecules and gene fragment expression revealed the amino acid residues that are shared by autoantibody-defined epitopes and microbial proteins . The presence of amino acid sequences shared between microbial proteins and autoantigens and the detection of antibodies in patients' sera that bind to the crossreactive epitopes suggest that immune responses to bacterial and viral infections may initiate the production of autoantibodies . Receptor-mediated phagocytosis of autoantigen molecules by crossreactive B cells and subsequent antigen presentation to helper T cells may facilitate the production of autoantibodies reactive with separate epitopes, if the autoantigen complex contains multiple B-cell epitopes and a shared T helper cell epitope . Analyses of the fine specificity of T helper cell epitopes on Friend murine leukemia virus env gene products revealed unexpected heterogeneity and redundancy of T cell responses even to a single epitope . This heterogeneity in T cell responses might play a role in the activation of self-reactive T helper cells through molecular mimicry.

Am J Orthod Dentofacial Orthop, 1997 Jun, 111(6), 591 - 4
Comparison of the effectiveness of two types of toothbrushes on the oral hygiene of patients undergoing orthodontic treatment with fixed appliances; Kilicoglu H et al.; The purpose of this study was to investigate whether orthodontic toothbrushes were superior to classical toothbrushes in the elimination of microbial dental plaque on teeth and brackets and in the maintenance of periodontal tissue health in patients, ages 12 to 22 years, with fixed appliances . Twenty patients undergoing orthodontic treatment with fixed appliances and brushing with the Bass technique were included in the study . Ten patients used the Oral B Ortho type toothbrushes (Oral B Laboratories Ltd.), whereas the remaining 10 patients used the Oral B Plus 35 type toothbrushes . Quigley-Hein plaque index, bonded bracket index, sulcus bleeding index, and periodontal pocket depth measurements were made at the beginning of the study and a month later . No statistically significant difference was found for plaque, sulcus bleeding, and periodontal pocket depth between Oral B Ortho and Plus 35 groups when the preinvestigatory and postinvestigatory measurements for the vestibular and proximal surfaces of upper and lower teeth were compared . This short-term study concluded that the Ortho-type toothbrush is not superior to the Plus 35-type toothbrush.

Orthopedics, 1997 Jun, 20(6), 525 - 38
Current concepts in the treatment of articular cartilage defects; Minas T et al.; Over time, articular cartilage loses the capacity to regenerate itself, making repair of articular surfaces difficult . Lavage and debridement may offer temporary relief of pain for up to 4.5 years, but offer no prospect of long-term cure . Likewise, marrow-stimulation techniques such as drilling, microfracture, or abrasion arthroplasty fail to yield long-term solutions because they typically promote the development of fibrocartilage . Fibrocartilage lacks the durability and many of the mechanical properties of the hyaline cartilage that normally covers articular surfaces . Repair tissue resembling hyaline cartilage can be induced to fill in articular defects by using perichondrial and periosteal grafts . However, these techniques are limited by the amount of tissue available for grafting and the tendency toward ossification of the repair tissue . Autogenous osteochondral arthroscopically implanted grafts (mosaicplasty), or open implantation of lateral patellar facet (Outerbridge technique), requires violation of subchondral bone . Osteochondral allografts risk viral transmission of disease and low chondrocyte viability, in addition to removal of host bone for implantation . Autologous chondrocyte implantation offers the opportunity to achieve biologic repair, enabling the surgeon to repair the joint surface with autologous articular cartilage . With this technique, care must be taken to ensure the safety, viability, and microbial integrity of the autologous cells while they are expanded in culture over a 4- to 5-week period prior to implantation . Surgical implantation requires equal attention to meticulous technique . In the future, physiologic repair also may become possible using mesenchymal stem cells or chondrocytes delivered surgically in an ex vivo-derived matrix . This would allow in vitro manipulation of cells with growth factors, mechanical stimuli, and matrix sizing to allow implantation of mature biosynthetic grafts which would allow treatment of larger defects with decreased rehabilitation and morbidity.

Plant Physiol, 1997 Jun, 114(2), 549 - 55
Adenylosuccinate synthetase from maize . Purification, properties, and mechanism of inhibition by 5'-phosphohydantocidin; Walters EW et al.; Adenylosuccinate synthetase (AdSS) is the site of action hydantocidin, a potent microbial phytotoxin . A kinetic analysis of the mode of inhibition of a plant adenylosuccinate synthetase by the active metabolite 5'-phosphohydantocidin (5'-PH) was the objective of the present study . AdSS was purified 5800-fold from maize (Zea mays), to our knowledge the first purification of the enzyme from a plant source . N-terminal sequencing established the cleavage site of the previously published deduced sequence of the initial transcript . The subunit molecular mass was determined to be 48 kD and the isoelectric point was at pH 6.1 . Values of the Michaelis constant for the three substrates IMP, GTP, and aspartate were 21, 16, and 335 microM, respectively . Inhibition of AdSS by 5'-PH was measurably time-dependent . The trace of the inactivation curve could not be altered by preincubating the enzyme and inhibitor in the absence of substrates but could be linearized by preincubating the enzyme with inhibitor, aspartate, GTP (or GDP), and inorganic phosphate . Inhibition of AdSS by 5'-PH was competitive with IMP, with an apparent Ki of 22 nM . Apparently, 5'-PH inhibits the enzyme by binding to the IMP site and forming a tight, dead-end complex.

Transfusion, 1997 Jun, 37(6), 585 - 91
Liquid nitrogen freezers: a potential source of microbial contamination of hematopoietic stem cell components; Fountain D et al.; BACKGROUND: The recent report of hepatitis B transmission between hematopoietic progenitor and putative stem cell (HPC) components stored in liquid nitrogen led to the questioning of whether evidence existed for similar contamination by bacterial or fungal elements . STUDY DESIGN AND METHODS: Microbial contamination rates were reviewed for 704 HPC components from 255 patients over an 18-month period . Five liquid nitrogen freezers were surveyed for microbial contamination . The literature was reviewed to ascertain the published experience of other laboratories with HPC component contamination first documented on thawing . RESULTS: Seven (1.2%) of 583 thawed components were found to be contaminated with a variety of environmental or waterborne organisms, despite a meticulous protocol to prevent contamination during thawing . All of these components had been sterile on cryopreservation . Literature review revealed a similar incidence of post-thaw contamination from other centers . Microbial survey of liquid nitrogen freezers revealed low-level contamination in four of five . The organisms represented were similar to those cultured from thawed HPC components . One freezer was heavily contaminated by Aspergillus species . CONCLUSION: Liquid nitrogen freezers are not sterile, and both the liquid and vapor phases are potential sources of microbial contamination of HPC components . While low-level contamination by environmental organisms may be common, the occurrence of heavy contamination by potential pathogens such as Aspergillus species suggests that monitoring of liquid nitrogen sterility may be indicated . Strategies to assess and prevent microbial transmission from liquid nitrogen to HPC components need further development.

Neurology, 1997 Jun, 48(6), 1643 - 53
Th1 epitope repertoire on the alpha subunit of human muscle acetylcholine receptor in myasthenia gravis; Wang ZY et al.; In myasthenia gravis (MG), CD4+ T helper cells recognize the muscle acetylcholine receptor (AChR) alpha subunit . We investigated the epitope repertoire of anti-AChR blood CD4+ Th1 cells from 13 myasthenic patients and three healthy controls, using overlapping synthetic peptides screening the alpha subunit sequence and an enzyme-linked immunospot (ELISPOT) assay that detects antigen-induced interferon-gamma secretion of individual Th1 cells . All patients recognized a pool of the alpha subunit peptides . All but one patient recognized numerous peptides . Each patient had an individual pattern of peptide recognition, but most or all patients recognized four sequences (residues 48-67, 101-137, 304-322, and 403-437) that stimulated relatively large numbers of Th1 cells . They include previously identified "immunodominant" sequences recognized by AChR-specific CD4+ T cell lines from myasthenic patients . Peptide 1-14 was also recognized frequently . The controls recognized, with a low precursor frequency, the peptide pool and a few peptides that frequently included the immunodominant sequences described above . The present results demonstrate that Th1 cells are involved in the anti-AChR response in MG and that their epitope repertoire is very complex . This indicates that when MG is clinically evident, the AChR itself is the sensitizing antigen and the target of the autoimmune Th1 cells, although it does not exclude that molecular mimicry between one AChR epitope and a microbial structure may have triggered this autoimmune response . Although the complexity of the Th1 repertoire suggests that development of specific immunosuppressive treatments targeted on epitopes recognized by autoimmune T cells will be difficult, the existence of immunodominant T epitope sequences might facilitate that task.

Am J Respir Cell Mol Biol, 1997 Jun, 16(6), 621 - 8
Of mites and men: trypsin-like proteases in the lungs; Caughey GH; It is no surprise to anyone who has tried to memorize clotting and complement cascades that there are a great many trypsin-like proteases-too many, it may seem . This fecund enzyme family encompasses such a range of biological roles that other important members and functions are sure to await discovery . Of known trypsin-like proteases, few, if any, are lung-specific . Nonetheless, many contribute in ways critical to lung function, such as fighting microbial invaders, regulating the formation and removal of polymerized fibrin, and rejecting tumors or transplanted tissues . Some of these enzymes, such as plasminogen activators and mast cell tryptases, are native to the lung and live where they work; identical enzymes live and work in other tissues . Other enzymes, such as most complement and hemostatic proteases, are migrants, typically born elsewhere (e.g., the liver) . They pass through the lung, looking for something to do; if nothing is found, they pass on, circulating, perhaps to return later . Still others are unwanted, uninvited intruders, such as dust mite proteases . This minireview provides a selective glimpse of the lives of some of the trypsin-like enzymes at work in the lung and airways.

Protein Expr Purif, 1997 Jun, 10(1), 89 - 99
Rat dihydroorotate dehydrogenase: isolation of the recombinant enzyme from mitochondria of insect cells; Knecht W et al.; Mammalian dihydroorotate dehydrogenase (EC 1.3.99.11), the fourth enzyme of pyrimidine de novo synthesis is located in the mitochondrial inner membrane with functional connection to the respiratory chain . From the cDNA of rat liver dihydroorotate dehydrogenase cloned in our laboratory the first complete sequence of a mammalian enzyme was deduced . Two hydrophobic stretches centered around residues 20 and 357, respectively, and a short N-terminal mitochondrial targeting sequence of 10 amino acids was proposed . A recombinant baculovirus containing the rat liver cDNA for dihydroorotate dehydrogenase was constructed and used for virus infection and protein expression in Trichoplusia ni cells . The targeting of the recombinant protein to mitochondria of the insect cells was monitored by activity determination of dihydroorotate dehydrogenase in subcellular compartments in comparison to succinate dehydrogenase activity (EC 1.3.5.1), which is a specific marker enzyme of the inner mitochondrial membrane . The results of subcellular distribution were verified by Western blotting with anti-dihydroorotate dehydrogenase immunoglobulins . The activity of the recombinant enzyme in the mitochondria of infected insect cells was found to be about 570-fold above the level of dihydroorotate dehydrogenase in rat liver mitochondria . By cation exchange chromatography of the Triton X-114 solubilisate of mitochondria, dihydroorotate dehydrogenase was purified to give a specific activity of 15 U/mg at pH 8.0 . This was a marked progress over the six-step purification procedure of the enzyme from rat liver which resulted in a specific activity of 0.7 U/mg at pH 8.0 . The characteristic flavin absorption spectrum obtained with the recombinant enzyme gave strong evidence that the rodent enzyme is a flavoprotein . By enzyme kinetic studies K(m) values for dihydroorotate and ubiquinone were 6.4 and 9.9 microM with the recombinant enzyme, and were 5.0 and 19.7 microM, respectively, with the rat liver enzyme . After expression of only truncated forms of human dihydroorotate dehydrogenase, the present successful generation of the complete rodent enzyme using insect cells and the efficient procedure will promote structure and function studies of the eukaryotic dihydroorotate dehydrogenases in comparison to the microbial enzyme.

Appl Environ Microbiol, 1997 Jun, 63(6), 2224 - 31
Dynamics of a microbial community associated with manure hot spots as revealed by phospholipid fatty acid analyses; Frostegard A et al.; Microbial community dynamics associated with manure hot spots were studied by using a model system consisting of a gel-stabilized mixture of soil and manure, placed between layers of soil, during a 3-week incubation period . The microbial biomass, measured as the total amount of phospholipid fatty acids (PLFA), had doubled within a 2-mm distance from the soil-manure interface after 3 days . Principal-component analyses demonstrated that this increase was accompanied by reproducible changes in the composition of PLFA, indicating changes in the microbial community structure . The effect of the manure was strongest in the 2-mm-thick soil layer closest to the interface, in which the PLFA composition was statistically significantly different (P < 0.05) from that of the unaffected soil layers throughout the incubation period . An effect was also observed in the soil layer 2 to 4 mm from the interface . The changes in microbial biomass and community structure were mainly attributed to the diffusion of dissolved organic carbon from the manure . During the initial period of microbial growth, PLFA, which were already more abundant in the manure than in the soil, increased in the manure core and in the 2-mm soil layer closest to the interface . After day 3, the PLFA composition of these layers gradually became more similar to that of the soil . The dynamics of individual PLFA suggested that both taxonomic and physiological changes occurred during growth . Examples of the latter were decreases in the ratios of 16:1 omega 7t to 16:1 omega 7c and of cyclopropyl fatty acids to their respective precursors, indicating a more active bacterial community . An inverse relationship between bacterial PLFA and the eucaryotic 20:4 PLFA (arachidonic acid) suggested that grazing was important.

J Mol Evol, 1997 Jun, 44(6), 675 - 82
Coordinated amino acid changes in the evolution of mammalian defensins; Hughes AL et al.; The mammalian defensin molecule is a short, highly cationic peptide cytotoxic to both microbial and mammalian cells which is cleaved from a precursor including a signal peptide and a highly anionic propiece . A phylogenetic analysis of 28 complete sequences from five mammalian species (mouse, rat, guinea pig, rabbit, and human) showed species-specific clusters of sequences, indicating that the genes duplicated after divergence of these species . Comparison of rates of synonymous and nonsynonymous nucleotide substitution suggested that gene duplication has often been followed by a period in which diversification of the mature defensins at the amino acid level has been selectively favored . In some comparisons, it appeared that amino acid differences in this region have appeared in a nonrandom fashion so as to change the pattern of residue charges . Because it has been hypothesized that the negative charge in the propiece serves to balance the positive charge in the mature defensin and thus to prevent cytotoxicity prior to cleavage, we used a maximum likelihood method of reconstructing ancestral states in order to test whether this balance has been maintained over evolutionary time in spite of rapid diversification of the mature defensin at the amino acid level . Reconstructed ancestral sequences always maintained a charge balance between mature defensin and propiece, and changes in the net positive charge of the mature defensin were balanced by corresponding changes in the propiece . The results support the hypothesis that, in the evolution of these proteins, amino acid changes have occurred in a coordinated fashion so as to preserve an adaptive phenotype.

J Immunol, 1997 Jun 1, 158(11), 5087 - 90
Microbial products induce autoimmune disease by an IL-12-dependent pathway; Segal BM et al.; The development and exacerbation of autoimmune diseases are associated with antecedent infectious illness . Microbial products such as LPS, bacterial DNA, or oligonucleotides containing an unmethylated cytosine-guanine dinucleotide have cytokine modulating properties . These products converted quiescent myelin basic protein-specific T cells into effector cells capable of transferring experimental allergic encephalomyelitis . The disease-promoting properties of the microbial products were solely dependent on their capacity to induce the production of IL-12.

J Clin Microbiol, 1997 Jun, 35(6), 1382 - 4
Comparison of BACTEC 9240 Peds Plus medium and isolator 1.5 microbial tube for detection of Brucella melitensis from blood cultures; Yagupsky P et al.; The sensitivity and time to detection of Brucella melitensis by the BACTEC 9240 and the Isolator blood culture systems were compared in a prospective volume-controlled study . Blood sample aliquots, obtained from children with suspected brucellosis, were inoculated into a BACTEC 9240 Peds Plus bottle and into an Isolator 1.5 Microbial Tube . Overall, 122 pairs of blood samples for culture were obtained, and 28 (23%) were positive by at least one method . The BACTEC 9240 system detected all 28 positive cultures (sensitivity, 100%), and the Isolator system detected 22 positive cultures (sensitivity, 79%) (P = 0.023) . Among those 22 cultures positive by both methods, 21 (95%) and 15 (68%) were found to be positive within 3 days by the BACTEC and the Isolator systems, respectively; 8 (36%) were found to be positive at least 1 day earlier by the BACTEC instrument, and the remaining 14 were found to be positive by the two systems on the same day (P = 0.045) . The BACTEC 9240 blood culture system is more sensitive than the Isolator system for the detection of B . melitensis and is superior in terms of time to detection of the organism.

J Clin Microbiol, 1997 Jun, 35(6), 1361 - 8
Fatty acid characterization of rapidly growing pathogenic aerobic actinomycetes as a means of identification; McNabb A et al.; The fatty acid compositions of 39 type strains and 529 clinical or reference strains of pathogenic aerobic actinomycetes were analyzed after standardized culture by using the Microbial Identification System (MIS) . Library entries for each type strain were created by using the MIS Library Generation Software, and the fatty acid profiles of clinical and reference strains were compared to these library entries . The bacteria separated into two large groups based upon major amounts of branched-chain or of saturated or monounsaturated straight-chain fatty acids . Identification of isolates was possible by using only the type strains for comparison, but fatty acid heterogeneity occurred within most species.

Int J Cancer, 1997 May 29, 71(5), 776 - 9
Seroprevalences of hepatitis B and C viruses and Helicobacter pylori infection in a small, isolated population at high risk of gastric and liver cancer; Chen SY et al.; The objective of this study was to examine the seroprevalences of chronic infection with hepatitis B and C viruses and Helicobacter pylori in Matzu, a group of small islets with 5,566 civilian residents who have extremely high mortality from cancers of the stomach and liver . The standardized mortality ratios (SMR) of all cancer sites combined, liver cancer and stomach cancer in 1984-1993 were calculated using the general population in Taiwan as the referent (SMR = 100) . The SMRs (95% confidence interval) for all cancer sites combined, liver cancer and stomach cancer were 160 (131-195), 252 (170-360) and 351 (229-516), respectively, in Matzu . A health survey was carried out with 1,485 civilian residents aged 30 years or more, giving a response rate of 69% among those who were eligible . Serum samples were tested for antibodies against Helicobacter pylori (anti-HP) by enzyme-linked immunosorbent assay and hepatitis B surface antigen (HBsAg) and antibodies against hepatitis C virus (anti-HCV) by enzyme immunoassay . The seroprevalence was 61% for anti-HP, 24.7% for HBsAg and 1.8% for anti-HCV in Matzu . While mortality rates of liver and stomach cancers were significantly higher in Matzu than in Taiwan, the seroprevalences of anti-HP, HBsAg and anti-HCV in Matzu were similar to or even lower than those in Taiwan . These findings suggest the existence of risk factors other than microbial agents involved in the development of stomach and liver cancers.

Int J Food Microbiol, 1997 May 20, 36(2-3), 127 - 33
A regulatory perspective on the potential uses of microbial risk assessment in international trade; Hathaway SC et al.; The recent ratification of the World Trade Organisation Agreement will arguably be the most important factor in developing new sanitary measures for the international trade in food over the next decade . There is a markedly increased desire for quantitative data on the microbial risks associated with different classes of foods, and traditional good manufacturing practice (GMP)-based food hygiene requirements are coming under increasing challenge . As the risk assessment paradigm is increasing applied and as decision-making criteria for risk management become established, more emphasis will be placed on predictive microbiology as a means of generating exposure data and establishing critical limits for Hazard Analysis Critical Control Point (HACCP) plans . In this respect, developing international guidelines for risk management arguably presents the greatest challenge in establishing and maintaining quantitative Sanitary and Phytosanitary (SP) measures for food in international trade, and for judging their equivalence . Where specific industry sectors and regulators do not have jurisdiction over the entire food chain, from production of raw materials through to consumption, it will be difficult to apply the risk assessment paradigm in the design of HACCP plans . Thus, it appears that default to food safety objectives for many segments of food production chains subject to application of HACCP plans is inevitable in the medium term.

Int J Food Microbiol, 1997 May 20, 36(2-3), 103 - 9
Use of predictive microbiology in meat hygiene regulatory activity; Armitage NH; New Zealand is a supplier of refrigerated raw meat to world markets . To maintain this supply, from regulatory and commercial perspectives, production standards need to deliver products that are both hygienically adequate and commercially viable . A dynamic Temperature Function Integration (TFI) model, as a form of predictive microbiology, was used jointly by regulators and processors to develop justifiable criteria for the management of refrigeration during the production of hot and warm-boned meat, the post-slaughter handling of ovine carcasses and the handling of offals . Current processes operating according to accepted standards for Good Manufacturing Practice (GMP) were quantified in terms of TFI . The hygienic adequacy of new processes were similarly determined using the TFI model and compared to relevant GMP standards . From a regulatory perspective, the dynamic TFI model has provided a rapid and cost effective method of quantifying a temperature dependent process in terms of the potential for microbial proliferation . It has also produced a method for determining parameters for new or intended processes by comparing the potential for microbial proliferation with previously validated outputs, and has complemented traditional quantitative microbiology to provide a rapid, cost effective method of verifying that a process is performing according to design parameters . However, it could not be used to validate standards for processing in the absence of existing standards for GMP, or in the absence of microbial standards previously established using the principles of risk assessment.

Biochem Pharmacol, 1997 May 15, 53(10), 1413 - 8
Cellular relocalisation of protein kinase C-theta caused by staurosporine and some of its analogues; Jones T et al.; The microbial product staurosporine is a protein kinase C (PKC) inhibitor with some phorbol ester-agonistic properties . It is known to cause the translocation of the PKC isoenzymes epsilon and delta from the cellular cytosol to the membrane and nucleus . We tested the hypothesis that it also affects the cellular localisation of the novel PKC isoenzyme theta, and that staurosporine analogues, some of which are currently under clinical evaluation as potential anticancer drugs, have a similar effect . Their ability to alter PKC-theta distribution was studied in human-derived A549 lung carcinoma cells . Western blot analysis and confocal microscopy after indirect immunofluorescence staining showed that staurosporine (100 nM), like the phorbol ester 12-O-tetradecanoylphorhol-13-acetate (25 nM) caused the translocation of PKC-theta from the cytosol to the membrane and the nucleus . The bisindolylmaleimide GF 109203X mimicked staurosporine, but had a weaker effect . Ro 31-8220 and UCN-01 decreased cytosolic PKC-theta only at 1 microM . CGP 41251 had no effect on PKC-theta in either experimental design . The results show that some, but not all, staurosporine analogues share the partial phorbol ester-agonistic PKC-translocatory activity of the parent molecule.

Structure, 1997 May 15, 5(5), 677 - 89
Two crystal structures of pectin lyase A from Aspergillus reveal a pH driven conformational change and striking divergence in the substrate-binding clefts of pectin and pectate lyases; Mayans O et al.; BACKGROUND: Microbial pectin and pectate lyases are virulence factors that degrade the pectic components of the plant cell wall . The homogalacturan backbone of pectin varies in its degree of methylation from the highly methylated and relatively hydrophobic form known as pectin, to the fully demethylated and highly charged form known as pectate . Methylated and demethylated regions of pectin are cleaved by pectin lyase and calcium-dependent pectate lyases, respectively . Protein engineering of lyases specific for particular patterns of methylation, will yield modified pectins of high value to the food and pharmaceutical industries . RESULTS: The crystal structures of pectin lyase A from two strains of Aspergillus niger, N400 and 4M-147, have been determined at pH 6.5 (2.4 A resolution) and pH 8.5 (1.93 A resolution), respectively . The structures were determined by a combination of molecular replacement, multiple isomorphous replacement and intercrystal averaging . Pectin lyase A folds into a parallel beta helix and shares many of the structural features of pectate lyases, despite no more than 17% sequence identity after pairwise structure-based alignment . These shared structural features include amino acid stacks and the asparagine ladder . However, the differences in the substrate-binding clefts of these two enzymes are striking . In pectin lyase A, the cleft is dominated by aromatic residues and is enveloped by negative electrostatic potential . In pectate lyases, this cleft is rich in charged residues and contains an elongated ribbon of positive potential when Ca2+ is bound . The major difference between the two pectin lyase A structures from the two strains is in the conformation of the loop formed by residues 182-187 . These observed differences are due to the different pH values of crystallization . CONCLUSIONS: The substrate-binding clefts and catalytic machinery of pectin and pectate lyases have diverged significantly . Specificity is dictated by both the nature of the protein-carbohydrate interaction and long-range electrostatic forces . Three potential catalytic residues have been identified in pectin lyase, two of these are common to pectate lyases . Pectin lyase A does not bind Ca2+ but an arginine residue is found in an equivalent position to the Ca2+ ion in pectate lyase, suggesting a similar role in catalysis . The activity of pectin lyase A is pH -dependent with an optimum activity at pH 5.5 . The activity drops above pH 7.0 due to a conformational change at the binding cleft, triggered by the proximity of two buried aspartate residues.

J Exp Med, 1997 May 5, 185(9), 1651 - 9
Identification of high potency microbial and self ligands for a human autoreactive class II-restricted T cell clone; Hemmer B et al.; CD4+ class II-restricted T cells specific for self antigens are thought to be involved in the pathogenesis of most human autoimmune diseases and molecular mimicry between foreign and self ligands has been implicated as a possible mechanism for their activation . In this report we introduce combinatorial peptide libraries as a powerful tool to identify cross-reactive ligands for these T cells . The antigen recognition of a CD4+ T cell clone (TCC) specific for myelin basic protein peptide (MBP) (86-96) was dissected by the response to a set of 220 11-mer peptide sublibraries . Based on the results obtained with the libraries for each position of the antigen, artificial peptides were found that induced proliferative responses at much lower concentrations than MBP(86-96) . In addition stimulatory ligands derived from protein sequences of self and microbial proteins were identified, some of them even more potent agonists than MBP(86-96) . These results indicate that: (a) for at least some autoreactive CD4+ T cells antigen recognition is highly degenerate; (b) the autoantigen used to establish the TCC represents only a suboptimal ligand for the TCC; (c) a completely random and unbiased approach such as combinatorial peptide libraries can decrypt the spectrum of stimulatory ligands for a T cell receptor (TCR).

Science, 1997 May 2, 276(5313), 734 - 40
A molecular view of microbial diversity and the biosphere; Pace NR; Over three decades of molecular-phylogenetic studies, researchers have compiled an increasingly robust map of evolutionary diversification showing that the main diversity of life is microbial, distributed among three primary relatedness groups or domains: Archaea, Bacteria, and Eucarya . The general properties of representatives of the three domains indicate that the earliest life was based on inorganic nutrition and that photosynthesis and use of organic compounds for carbon and energy metabolism came comparatively later . The application of molecular-phylogenetic methods to study natural microbial ecosystems without the traditional requirement for cultivation has resulted in the discovery of many unexpected evolutionary lineages; members of some of these lineages are only distantly related to known organisms but are sufficiently abundant that they are likely to have impact on the chemistry of the biosphere.

Anim Reprod Sci, 1997 May, 47(1-2), 71 - 90
Dietary excesses of urea influence the viability and metabolism of preimplantation sheep embryos and may affect fetal growth among survivors; McEvoy TG et al.; In the first of two experiments investigating the effect of dietary urea on the survival and metabolism of ovine embryos, 30 Border Leicester x Scottish Blackface ewes received a maintenance diet (milled hay, molasses, minerals, vitamins) with no urea (control, C; n = 10) or with added urea at 15 g (low urea, LU; n = 10) or 30 g (high urea, HU; n = 10) kg-1 feed for a 12 week period . The degraded nitrogen (N) status relative to estimated rumen microbial N requirements was -2, +9 and +20 g per day, respectively . One week after allocation to diets, progesterone priming (12 days) commenced . Ewes received 800 IU of equine chorionic gonadotrophin at progesterone withdrawal, were inseminated 52 h later (Day 0) and embryos were collected from five ewes per group at Day 4 and from five ewes at Day 11 . If available, one embryo was returned to each ewe; the rest were cultured in vitro . There was no effect of treatment on progesterone, luteinizing hormone (LH), or time of oestrus onset C, LU and HU plasma urea (P < 0.001) and ammonia levels (C vs . HU, P < 0.01; LU vs . HU, P < 0.05) differed . Day 4 HU embryos were retarded relative to C and LU embryos . After 3 days of culture, 70%, 66% and 0% of C, LU and HU embryos, respectively, were viable . Mid-term pregnancy rates following transfer were 63%, 43% and 33% . Only one HU lamb (male) was born following embryo transfer, its birthweight (10.1 kg) exceeded that of its C (n = 3; 7.0, 7.0, 7.5 kg) and LU (n = 2; 7.3, 8.2 kg) counterparts (P < 0.025) . In the second experiment, C2 (2.5 g urea kg-1; n = 5) and HU2 (30 g kg-1; n = 7) diets which provided similar intakes of degraded N relative to microbial requirements as those for C and HU ewes in Experiment 1 were fed to Border Leicester x Scottish Blackface ewes superovulated with 16 mg of porcine follicle-stimulating hormone . Urea and ammonia levels in utero-oviductal samples were elevated in HU2 ewes (P < 0.05) . At collection (Day 3), HU2 embryos used more glucose (P < 0.01) and, following culture, some exhibited up to a 2.8-fold increase in metabolism . In conclusion, excess rumen degradable N in ewe diets elevates urea and ammonia in plasma and in utero, with an associated increase in embryo mortality . Nevertheless, metabolism appears to be up-regulated in some embryos and, among those that survive, fetal growth appears to be enhanced.

Eur J Radiol, 1997 May, 24(3), 253 - 6
Community acquired pneumonia caused by M . tuberculosis--diagnosis with CT; van der Werf TS et al.; A female Somalian patient presenting with a clinical picture compatible with community-acquired bilateral lobe pneumonia failed to respond to empirical anti-microbial treatment . CT of the chest revealed cavitation of the apical segment of the right lower lobe, and this feature pointed to the correct diagnosis: tuberculous pneumonia, which was eventually confirmed with cultures taken during bronchoscopy . This is the first report of the use of chest CT in the diagnosis of lower lobe tuberculosis.

J Ind Microbiol Biotechnol, 1997 May, 18(5), 302 - 7
Microbial diversity: the importance of exploration and conservation; Colwell RR; Microbial diversity is fundamental to maintenance and conservation of global genetic resources . As extreme environments are explored, the richness of microbial diversity is increasingly evident . Measures must be taken to estimate, record, and conserve microbial diversity, not only to sustain human health but also to enrich the human condition globally through wise use and conservation of genetic resources of the microbial world.

Anticancer Res, 1997 May-Jun, 17(3C), 1881 - 6
Effects of cytogenin, a novel microbial product, on embryonic and tumor cell-induced angiogenic responses in vivo; Oikawa T et al.; Cytogenin (8-hydroxy-3-hydroxymethyl-6-methoxyisocoumarin) is a new microbial product with antitumor and antirheumatoid arthritis effects in vivo when administered orally, although its mechanism(s) of action is not known well . Both neoplasia and rheumatoid arthritis are referred to as angiogenesis-dependent diseases . The aim of the present study was to investigate the effects of cytogenin on both physiological and pathological angiogenesis, using the growing chick embryo chorioallantoic membrane and mouse dorsal air sac assay systems, respectively . The microbial product at doses up to 100 micrograms/egg did not significantly affect embryonic angiogenesis when topically placed on the surface of the chorioallantoic membrane, suggesting that it has no effect on the physiological (or normal) angiogenic response . By contrast, systemic administration of cytogenin (100 mg/kg p.o., for 5 consecutive days) significantly suppressed angiogenesis induced by malignant tumor cells (S-180), one of pathological neovascularization, in a mouse dorsal air sac assay system . Pharmacokinetic studies in mice revealed that the maximal concentration of cytogenin in plasma after a single 100 mg/kg oral dose of the compound was 32 microM . In vitro experiments involving cultured vascular endothelial cells showed that cytogenin at concentrations determined by pharmacokinetic study, had little effect on plasminogen activator secretion, tube formation and the proliferation of endothelial cells . These results suggest that cytogenin is a novel oral antiangiogenic agent, that the mechanism of its antiangiogenic action contributes to its suppressive effects on both tumor growth and rheumatoid arthritis that we previously found, and that it could be developed as a potential therapeutic agent for cancer, rheumatoid arthritis and other angiogenesis-dependent disorders such as diabetic retinopathy.

Antonie Van Leeuwenhoek, 1997 May, 71(4), 369 - 73
Changes in the starvation response through covalent cell attachment; Jirku V; Covalent attachment of Candida utilis cells, possibly simulating natural microbial immobilizations, stimulated stable and significant enhancement of extracellular production of alkaline protease, specifically induced by four different starvation conditions . The enzyme analysis confirmed the identity of the proteases released under all conditions of starvation and no parallel production of other proteolytic enzyme . The enhancement phenomenon as a uniform and stable effect of the whole cell immobilization is discussed in relation to the effect of multipoint, cell-solid surface contact, potentially bringing positive modulations of complex, cellular functions.

Antonie Van Leeuwenhoek, 1997 May, 71(4), 345 - 51
Physiological characterization of a microbial sensor containing the yeast Arxula adeninivorans LS3; Riedel K et al.; The yeast Arxula adeninivorans LS3 is a suitable organism for use as part of a microbial sensor . In combination with an amperometric oxygen electrode the sensor offered a possibility for the physiological characterization of this yeast . About 300-400 measurements could be carried out with a single Arxula sensor . The microbial sensor was remarkably stable for over 35 days, when kept at 37 degrees C during the operation time and at room temperature overnight . The physiological characteristics of Arxula adeninivorans LS3 obtained with the sensor technique were identical to the data obtained with the conventional techniques . However, the sensor technique makes it additionally possible to quantify the physiological data . So the substrates ribose, citric acid, glycerol, oil and benzoate produced signals lower than 10% in comparison to the glucose signal . Fructose, xylose, sucrose, maltose, gentianose, glucosamine, glutamic acid, tryptophan, butyric acid, lauryl acid and propionic acid reached 10-70%, galactose, alanine, glycine, lysine and methionine signals were similar to the glucose signal whereas acetic acid, ethyl alcohol, capron acid, capryl acid and caproic acid reached the highest signals up to 434%.

Cell Mol Biol (Noisy-le-grand), 1997 May, 43(3), 337 - 44
New autoantibodies and their antigens in autoimmune diseases; Storch WB; Autoimmune diseases are caused by failure to distinguish between host and foreign (e.g . microbial) antigens . We do not know why autoimmune disease occurs and what the relevant pathogenic mechanisms are . Autoantibodies might be considered as diagnostic markers, e.g . as "witnesses" to or "messengers" of autoimmune disease . Therefore, older and newer autoantibodies, as well as results on their respective antigens, will be considered.

J Biochem (Tokyo), 1997 May, 121(5), 930 - 4
Renaturation, purification, and characterization of human plasminogen activator inhibitor type 2 (PAI-2) accumulated at high level in Escherichia coli; Zhou A et al.; Plasminogen activator inhibitor 2 (PAI-2) is an important regulator of plasminogen activation, which inhibits both tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) . In this study we have developed a high-level expression system by inserting a modified PAI-2 gene downstream of the T7 promoter . The expression level of recombinant PAI-2 amounted to 55-60% of total microbial protein . By efficient renaturation and one-step purification, the recombinant protein was purified to homogeneity . The specific activity and yield of recombinant PAI-2 reached 33,000 IU/mg and 10 mg per gram wet weight of Escherichia coli cells, respectively . The second-order rate constant for uPA was 2.6-2.8 x 10(6) M(-1) x s(-1).

Cancer Immunol Immunother, 1997 May, 44(3), 137 - 49
Phase IB trial of picibanil (OK-432) as an immunomodulator in patients with resected high-risk melanoma; Kirkwood JM et al.; The microbial immunostimulant OK-432 has been studied intensively in preclinical systems and has shown promise as an anticancer agent in trials that have been conducted over the past 20 years in Japan . To date, no systematic dose response evaluation of this agent has defined its dose-limiting toxicity or immunobiological activity . A phase IA study has been conducted in 25 patients with metastatic cancer at the University of Pittsburgh Cancer Institute Melanoma Center, establishing 30 KE as the maximal tolerable dosage, on the basis of cutaneous reactions . Subsequently, 48 patients with resected high-risk melanoma participated in a phase IB study of OK-432 . This study has evaluated the immunomodulatory activity of OK-432 at five dosages ranging from 1 KE to 20 KE, administered ID twice weekly for 3 months . A formal analysis of the treated population in comparison to the randomized control group has been conducted, and profound immunological effects have been defined in the group of patients treated with OK-432 . Patients who participated in this trial had a significant depression of OK-432-inducible cytokine production (interleukin-1 beta, interferon gamma, and tumor necrosis factor alpha) at baseline . Treatment with OK-432 reversed this deficit for interferon gamma (IFN gamma) production in a dose-dependent manner, and mitigated the inhibition for interleukin-1 (IL-1) across all dosage groups . The impact of OK-432 upon other immunological functions of the treated cohorts is more variable, with durable suppression of mononuclear cell superoxide production, and in vitro cytotoxicity to tumor . Immunological characteristics of the entire cohort demonstrate a strong and significant correlation of elevated blood CD16+ cell counts and natural killer activity with early tumor progression and death due to melanoma . Favorable prognosis is associated with monocyte capacity to produce tumor necrosis factor (TNF), and polymorphonuclear leukocyte formylmethionyl-leucylphenylalanine-inducible superoxide release . This study reveals several new immunological correlates of tumor progression and lethal outcome in resected high-risk melanoma . It demonstrates that the depressed IL-1, TNF, and IFN gamma release associated with melanoma may be mitigated by treatment with OK-432 . This study has defined treatment and dose response patterns of immunomodulation associated with one of the most complex immunological agents yet evaluated in phase IB trials, in a well-defined population of high-risk patients with resected melanoma.

J Refract Surg, 1997 May-Jun, 13(3), 314 - 7
Nocardial keratitis after laser in situ keratomileusis; Perez-Santonja JJ et al.; PURPOSE AND METHODS: Corneal interface central nodules appeared in a patient who underwent uncomplicated laser in situ keratomileusis (LASIK) retreatment for residual myopia . RESULTS/CONCLUSIONS: Nocardia asteroides keratitis was confirmed by microbiologic studies, which guided treatment . Six months after the appearance of the keratitis, the patient's uncorrected visual acuity was 20/45, and spectacle-corrected visual acuity was 20/40 . The postoperative refraction was +0.75 -0.75 X 95 degrees, and slit-lamp examination revealed a clear cornea with a mild rounded scar in the central area . Night halos and starbursts were the main complaints in this patient . The immediate management of lifting the corneal flap for stromal bed scraping, fast microbial identification, and proper treatment was the key for the results in this patient.

J Eukaryot Microbiol, 1997 May-Jun, 44(3), 200 - 5
Trophic controls on stage transformations of a toxic ambush-predator dinoflagellate; Burkholder JM et al.; The toxic dinoflagellate, Pfiesteria piscicida, was recently implicated as the causative agent for about 50% of the major fish kills occurring over a three-year period in the Albemarle-Pamlico Estuarine System of the southeastern USA . Transformations between life-history stages of this dinoflagellate are controlled by the availability of fresh fish secretions or fish tissues, and secondarily influenced by the availability of alternate prey including bacteria, algae, microtauna, and mammalian tissues . Toxic zoospores of P . piscicida subdue fish by excreting lethal neurotoxins that narcotize the prey, disrupt its osmoregulatory system, and attack its nervous system . While prey are dying, the zoospores feed upon bits of fish tissue and complete the sexual phase of the dinoflagellate life cycle . Other stages in the complex life cycle of P . piscicida include cryptic forms of filose, rhizopodial, and lobose amoebae that can form within minutes from toxic zoospores, gametes, or planozygotes . These cryptic amoebae feed upon fish carcasses and other prey and, thus far, have proven less vulnerable to microbial predators than flagellated life-history stages . Lobose amoebae that develop from toxic zoospores and planozygotes during colder periods have also shown ambush behavior toward live fish . In the presence of abundant flagellated algal prey, amoeboid stages produce nontoxic zoospores that can become toxic and form gametes when they detect what is presumed to be a threshold level of a stimulatory substance(s) derived from live fish . The diverse amoeboid stages of this fish "ambush-predator" and at least one other Pfiesteria-like species are ubiquitous and abundant in brackish waters along the western Atlantic and Gulf Coasts, indicating a need to re-evaluate the role of dinoflagellates in the microbial food webs of turbid nutrient-enriched estuaries.

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