J Zoo Wildl Med, 1998 Jun, 29(2), 214 - 20 Gastric spiral bacteria in small felids; Kinsel MJ et al.; Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F . manul), one Canada lynx (F . lynx canadensis), two fishing cats (F . viverrina), two margays (F . wiedii), and two sand cats (F . margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P . uncia), one Siberian tiger (P . tigris altaica), and one jaguar (P . onca), necropsied during the same period had none . All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar . Histologically, the spiral bacteria were 5-14 microm long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells . Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrewlike to tumbling motility when viewed with phase contrast microscopy . The bacteria were 0.5-0.7 microm wide, with a periodicity of 0.65-1.1 microm in all cats . Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen . The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells . Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful . Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms . Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens. Int J Syst Bacteriol, 1998 Apr, 48 Pt 2, 469 - 74 Desulfobulbus rhabdoformis sp . nov., a sulfate reducer from a water-oil separation system; Lien T et al.; A mesophilic, Gram-negative, rod-shaped, marine, propionate-oxidizing sulfate reducer (strain M16T) was isolated from a water-oil separation system on a North Sea oil platform . The optimum conditions for growth were 31 degrees C, pH 6.8-7.2 and 1.5-2.0% (w/v) NaCl and 0.1-0.3% (w/v) MgCl2.6H2O in the medium . The growth yield with sulfate was 4.6 g cell biomass (mol propionate oxidized)-1 . Strain M16T is nutritionally related to members of the genus Desulfobulbus, but differs in that it has no vitamin requirement and is able to utilize fumarate and malate as carbon and energy sources . Hydrogenase activity measured as hydrogen uptake was mainly membrane-bound and varied with the growth substrate . Highest activity {28 mumol min-1 (mg protein)-1} was found in cells grown with hydrogen and lowest {50 nmol min-1 (mg protein)-1} in cells grown with propionate as electron donors for sulfate reduction . Desulforubidin, menaquinone-5(H2) and cytochromes of the c- and b-type were present . The fatty acid pattern was similar to that found for Desulfobulbus propionicus . The DNA base composition was 50.6 mol% G + C . Strain M16T is equidistantly related to D . propionicus and Desulfobulbus elongatus with 96.1% 16S rDNA similarity . On the basis of differences in genotypic, phenotypic and immunological characteristics, strain M16T (= DSM 8777T) is proposed as the type strain of a new species, Desulfobulbus rhabdoformis. Int J Syst Bacteriol, 1998 Apr, 48 Pt 2, 339 - 48 Alcanivorax borkumensis gen . nov., sp . nov., a new, hydrocarbon-degrading and surfactant-producing marine bacterium; Yakimov MM et al.; During screening for biosurfactant-producing, n-alkane-degrading marine bacteria, six heterotrophic bacterial strains were isolated from enriched mixed cultures, obtained from sea water/sediment samples collected near the isle of Borkum (North Sea), using Mihagol-S (C14,15-n-alkanes) as principal carbon source . These Gram-negative, aerobic, rod-shaped bacteria use a limited number of organic compounds, including aliphatic hydrocarbons, volatile fatty acids, and pyruvate and its methyl ether . During cultivation on n-alkanes as sole source of carbon and energy, all strains produced both extracellular and cell-bound surface-active glucose lipids which reduced the surface tension of water from 72 to 29 mN m-1 (16) . This novel class of glycolipids was found to be produced only by these strains . The 16S rRNA gene sequence analysis showed that these strains are all members of the gamma-subclass of the Proteobacteria . Their phospholipids ester-linked fatty acid composition was shown to be similar to that of members of the genus Halmonas, although they did not demonstrate a close phylogenetic relationship to any previously described species . On the basis of the information summarized above, a new genus and species, Alcanivorax borkumensis, is described to include these bacteria . Strain SK2T is the type strain of A . borkumensis. Biol Signals Recept, 1998 Jul-Aug, 7(4), 195 - 219 Prospects of the clinical utilization of melatonin; Bubenik GA et al.; This review summarizes the present knowledge on melatonin in several areas on physiology and discusses various prospects of its clinical utilization . Ever increasing evidence indicates that melatonin has an immuno-hematopoietic role . In animal studies, melatonin provided protection against gram-negative septic shock, prevented stress-induced immunodepression, and restored immune function after a hemorrhagic shock . In human studies, melatonin amplified the antitumoral activity of interleukin-2 . Melatonin has been proven as a powerful cytostatic drug in vitro as well as in vivo . In the human clinical field, melatonin appears to be a promising agent either as a diagnostic or prognostic marker of neoplastic diseases or as a compound used either alone or in combination with the standard cancer treatment . Utilization of melatonin for treatment of rhythm disorders, such as those manifested in jet lag, shift work or blindness, is one of the oldest and the most successful clinical application of this chemical . Low doses of melatonin applied in controlled-release preparation were very effective in improving the sleep latency, increasing the sleep efficiency and rising sleep quality scores in elderly, melatonin-deficient insomniacs . In the cardiovascular system, melatonin seems to regulate the tone of cerebral arteries; melatonin receptors in vascular beds appear to participate in the regulation of body temperature . Heat loss may be the principal mechanism in the initiation of sleepiness caused by melatonin . The role of melatonin in the development of migraine headaches is at present uncertain but more research could result in new ways of treatment . Melatonin is the major messenger of light-dependent periodicity, implicated in the seasonal reproduction of animals and pubertal development in humans . Multiple receptor sites detected in brain and gonadal tissues of birds and mammals of both sexes indicate that melatonin exerts a direct effect on the vertebrate reproductive organs . In a clinical study, melatonin has been used successfully as an effective female contraceptive with little side effects . Melatonin is one of the most powerful scavengers of free radicals . Because it easily penetrates the blood-brain barrier, this antioxidant may, in the future, be used for the treatment of Alzheimer's and Parkinson's diseases, stroke, nitric oxide, neurotoxicity and hyperbaric oxygen exposure . In the digestive tract, melatonin reduced the incidence and severity of gastric ulcers and prevented severe symptoms of colitis, such as mucosal lesions and diarrhea. Appl Environ Microbiol, 1998 Sep, 64(9), 3507 - 11 Pseudomonas sp . strain 273, an aerobic alpha, omega-dichloroalkaneDegrading bacterium; Wischnak C et al.; A gram-negative, aerobic bacterium was isolated from soil; this bacterium grew in 50% (vol/vol) suspensions of 1,10-dichlorodecane (1,10-DCD) as the sole source of carbon and energy . Phenotypic and small-subunit ribosomal RNA characterizations identified the organism, designated strain 273, as a member of the genus Pseudomonas . After induction with 1,10-DCD, Pseudomonas sp . strain 273 released stoichiometric amounts of chloride from C5 to C12 alpha, omega-dichloroalkanes in the presence of oxygen . No dehalogenation occurred under anaerobic conditions . The best substrates for dehalogenation and growth were C9 to C12 chloroalkanes . The isolate also grew with nonhalogenated aliphatic compounds, and decane-grown cells dechlorinated 1,10-DCD without a lag phase . In addition, cells grown on decane dechlorinated 1,10-DCD in the presence of chloramphenicol, indicating that the 1,10-DCD-dechlorinating enzyme system was also induced by decane . Other known alkane-degrading Pseudomonas species did not grow with 1,10-DCD as a carbon source . Dechlorination of 1,10-DCD was demonstrated in cell extracts of Pseudomonas sp . strain 273 . Cell-free activity was strictly oxygen dependent, and NADH stimulated dechlorination, whereas EDTA had an inhibitory effect. Am J Physiol, 1998 Sep, 275(3 Pt 1), E479 - 86 Endotoxin-induced migration of monocytes and PECAM-1 phosphorylation are abrogated by PAF receptor antagonists; Shen Y et al.; The trafficking of monocytes across the endothelial lining of the blood vessel increases in response to bacterial infection at sites of inflammation . However, the molecular events involved in the diapedesis of monocytes in response to endotoxin are not completely understood . Our studies revealed that signaling by lipopolysaccharide (LPS) in human umbilical vein endothelial cells (HUVEC) resulted in a threefold increase in the transendothelial migration of monocyte-like HL-60 cells and a sevenfold increase in the phosphorylation of platelet endothelial cell adhesion molecule-1 (PECAM-1) . The transmigration induced by LPS was inhibited by an antibody to PECAM-1 . Both the phosphorylation of PECAM-1 and transendothelial migration of monocytes were inhibited by a platelet-activating factor (PAF) receptor antagonist, indicating the autocrine effect of PAF in these events . Treatment of HUVEC with LPS caused a fourfold increase in PAF receptor mRNA expression that was completely blocked by the PAF receptor antagonist . We conclude that PAF, generated by HUVEC in response to LPS or gram-negative bacterial infection, acts in an autocrine manner, causing PECAM-1 phosphorylation and thus the transendothelial migration of monocytes. Curr Opin Rheumatol, 1998 Jul, 10(4), 330 - 4 Bacterial arthritis; Ike RW; Reports pertinent to bacterial arthritis in 1997 included two large, multi-year surveys of joint infection in patients from defined European health districts, noting trends including the declining incidence of gonococcal arthritis and an increasing number of prosthetic joint infections . Children with infected joints generally fare better than adults despite having proportionately more infections due to gram-negative organisms, of which Hemophilus influenzae comprises an ever smaller portion as the fastidious Kingella kingea is emerging . Joint infections remain an uncommon complication of immunodeficiency due to HIV, with responsible agents, affected sites, and clinical course also influenced by certain HIV comorbidities such as intravenous drug user and hemophilia . The rare immunodeficient patient with hypogammaglobulinemia retains a nearly unique susceptibility to joint infection with mycoplasmas, which can cause considerable morbidity if not promptly recognized and treated . Polymerase chain reaction can detect remnants of bacteria in the face of negative conventional cultures, but inoculation of synovial fluid into blood cultures bottles may be a more immediate and practical method to increase the yield in suspected septic arthritis. Ann Periodontol, 1998 Jul, 3(1), 213 - 21 The East London Study of Maternal Chronic Periodontal Disease and Preterm Low Birth Weight Infants: study design and prevalence data; Davenport ES et al.; The influence of subject-based and environmental factors on the balance between the subgingival microbial challenge and the host response in periodontal diseases illustrates the intimate link between oral and systemic health . From this stems the hypothesis that the persistent Gram-negative challenge and associated inflammatory sequelae in periodontal disease may have consequences extending beyond the periodontal tissues themselves . This paper addresses the design of a case-control study to examine the relationship between preterm low birth weight (PLBW) and maternal periodontal disease . We present preliminary data on the prevalence of these 2 conditions in a group of mothers at the Royal Hospitals Trust, London, U.K . Cases are defined as mothers delivering an infant weighing less than 2,500g before 37 weeks gestation and controls as mothers delivering an infant of more than 2,500g after 38 weeks . We estimated that a study involving 800 mothers (1:3 case:control) should have sufficient power to detect an association with a minimum odds ration of 3 at the 5% significance level . Demographic details of 177 subjects demonstrated that they were representative of the local population, and the prevalence of PLBW was within the expected range . However, the extent and severity of periodontal disease were higher than predicted and may have reflected elevations in gingival inflammation associated with pregnancy . The final outcome of the study should help determine the need for further interventionist studies to demonstrate a causal relationship between periodontal disease and PLBW, as well as provide information on the prevalence of periodontal diseases in this study population. Ann Periodontol, 1998 Jul, 3(1), 40 - 50 PGE2, IL-1 beta, and TNF-alpha responses in diabetics as modifiers of periodontal disease expression; Salvi GE et al.; Diabetes mellitus is a systemic disease that affects more than 12 million people in the United States and represents a risk factor for periodontitis with odds ratios of 2.1 to 3.0 . New data support the concept that in diabetes-associated periodontitis, the altered host inflammatory response plays a critical role . We have recently examined the gingival crevicular fluid (GCF) mediator level, monocytic secretion, and clinical presentation of 39 insulin-dependent diabetes mellitus (IDDM) patients and 64 non-diabetic patients with various degrees of periodontal health and disease . First, we found that there was an unexpected high level of GCF mediators among the IDDM subjects, even in the gingivitis and mild periodontitis patients . Furthermore, the GCF and monocytic mediator responses were obviously bimodal in distribution with respect to periodontal status . Gingivitis patients and mild periodontitis patients represented one low response group, and the moderate and severe periodontitis subjects the high response group . Accordingly, these 4 periodontal subgroups were pooled to form 2 main groups for analyses--group A (AAP Types I-II) and group B (AAP Types III-IV) . Diabetics had significantly higher GCF levels of both PGE2 and IL-1 beta when compared to non-diabetic controls with similar periodontal status . Within the diabetic group, the GCF levels of these inflammatory mediators were almost 2-fold higher in group B subjects when compared to diabetics from group A . Among diabetics, GCF TNF-alpha levels were only marginally detectable and no significant difference was found between group A and group B patients . Insulin-dependent diabetic patients with gingivitis or mild periodontitis (group A) and moderate to severe periodontitis (group B) have abnormal monocytic inflammatory secretion in response to LPS challenge from Porphyromonas gingivalis (P . gingivalis) as compared to non-diabetic periodontal patients . Data suggest that the diabetic state results in a significantly upregulated monocytic secretion of PGE2 (4.2-fold), IL-1 beta (4.4-fold), and TNF-alpha (4.6-fold) when compared to non-diabetic controls . Within diabetics, LPS dose-response curves demonstrated that monocytes from group B patients secreted approximately 3 times more PGE2 and 6.2 times more TNF-alpha than those from group A; however, there was no significant difference in monocytic IL-1 beta secretion between the 2 diabetic groups . This upregulated monocytic trait is thought to exist independently of the presence of severe periodontal disease since, in non-diabetic patients with adult periodontitis, Gram-negative bacterial infections alone are not sufficient to elicit a systemic hyperresponsive monocytic trait . Between group A and group B diabetics, there was no significant difference in metabolic control as expressed by mean level of glycosylated hemoglobin (HbA1c) . In conclusion, our data suggest that diabetic patients have exaggerated inflammatory responses when compared to non-diabetic controls . Furthermore, within diabetics, individuals with moderate to severe periodontitis (group B) have significantly elevated monocytic secretion of PGE2 and TNF-alpha upon LPS challenge and significantly higher GCF levels of PGE2 and IL-1 beta when compared to patients with gingivitis or mild periodontal disease (group A) . Thus, we suggest that insulin-dependent diabetes mellitus is a significant risk factor for more severe periodontal disease because, as compared to non-diabetics, diabetic subjects react with an abnormally high degree of inflammation to an equivalent bacterial burden. Eur J Clin Microbiol Infect Dis, 1998 May, 17(5), 349 - 52 Two epidemiologically related cases of Rahnella aquatilis bacteremia; Caroff N et al.; Rahnella aquatilis was isolated from the blood cultures of two patients who were in different units of the same hospital . Both isolates were susceptible to aminoglycosides, fluoroquinolones, cotrimoxazole, piperacillin, third generation cephalosporins and amoxicillin-clavulanate, but resistant to amoxicillin, ticarcillin, and first generation cephalosporins . The synergistic activity of amoxicillin and clavulanic acid suggested the presence of a beta-lactamase, confirmed by a positive nitrocefin test and by analytical isoelectric focusing . Pulsed-field gel electrophoresis and ribotyping with the pKK3535 probe showed that the isolates shared the same banding pattern . The results of an epidemiological study suggested that an in-house total parenteral nutrition solution might be the source of this unusual gram-negative rod. J Appl Microbiol, 1998 Mar, 84(3), 349 - 56 The incidence of Weeksella- and Bergeyella-like bacteria in the food environment; Botha WC et al.; Eighty-five catalase- and oxidase-positive Gram-negative rods and cocci susceptible to penicillin G were isolated from a variety of food sources . The phenotypic relationships of these isolates with reference cultures of Bergeyella-like, Chryseobacterium, Empedobacter, Myroides, Moraxella, Sphingobacterium and Weeksella-like strains were examined by numerical taxonomy . Seventy-three isolates were recovered in five groups; 80% of the isolates clustered in groups 1, 2 and 3 and produced indole, bearing a strong resemblance to Weeksella and Bergeyella . They could not, however, be regarded as belonging to the known species of W . virosa and B . zoohelcum . It is suggested that three species may be necessary to accommodate the environmental Weeksella- or Bergeyella-like bacteria . The isolates in groups 4 and 5 had white colonies and were unable to produce indole, in this way resembling the Moraxella genus. J Bacteriol, 1998 Sep, 180(17), 4435 - 41 Chitinolytic activity in Chromobacterium violaceum: substrate analysis and regulation by quorum sensing; Chernin LS et al.; Quorum sensing control mediated by N-acyl homoserine lactone (AHL) signaling molecules has been established as a key feature of the regulation of exoenzyme production in many gram-negative bacteria . In Chromobacterium violaceum ATCC 31532 a number of phenotypic characteristics, including production of the purple pigment violacein, hydrogen cyanide, antibiotics, and exoproteases are known to be regulated by the endogenous AHL N-hexanoyl-L-homoserine lactone (HHL) . In this study we show that C . violaceum produces a set of chitinolytic enzymes whose production is regulated by HHL . The chitinolytic activity was induced in strains grown in the presence of chitin as the sole carbon source and quantitated in the secreted proteins by using p-nitrophenol analogs of disaccharide, trisaccharide, and tetrasaccharide oligomers of N-acetylglucosamine . By using 4-methylumbelliferyl analogs of the same oligomers of N-acetylglucosamine as substrates for proteins separated and renatured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, at least six enzymes were detected: a chitobiase with high specificity to a dimeric substrate of 87 kDa, two N-acetylglucosaminidases with apparent molecular masses of 162 and 133 kDa, two endochitinases of 108 and 67 kDa, and a chitobiosidase of 56 kDa . In addition, two unidentified bands of >205 kDa were found where a tetrameric chitin derivative was used as a substrate . A pleiotropic mini-Tn5 mutant of C . violaceum (CV026) that is defective in HHL production and other quorum-sensing-regulated factors was also found to be completely deficient in chitinolytic activity . Growth of this mutant on minimal medium with chitin supplemented with culture supernatant from the C . violaceum wild-type strain or 10 microM synthetic HHL restored chitinase production to the level shown by the parental strain . These results constitute the most complete evidence so far for regulation of chitinolytic activity by AHL signaling in a gram-negative bacterium. Haematologica, 1998 Jul, 83(7), 670 - 2 Bacteremia caused by CDC group IV c-2 in a patient with acute leukemia; Salar A et al.; Human infection due to CDC group IV c-2, a gram negative bacillous, are rare . We describe a case of nosocomial bacteremia caused by this organism in a neutropenic patient with acute lymphoblastic leukemia and include a literature review of CDC group IV c-2 infection in patients with hematologic malignancies. Infection, 1998 Jul-Aug, 26(4), 213 - 21 An analysis of interleukin-8, interleukin-6 and C-reactive protein serum concentrations to predict fever, gram-negative bacteremia and complicated infection in neutropenic cancer patients; Engel A et al.; A prospective study was performed to assess the potential value of interleukin (IL)-8, IL-6, and C-reactive protein (CRP) serum levels to predict fever, gram-negative bacteremia and complicated infection in neutropenic patients with cancer . Serum samples were obtained three times a week during 208 neutropenic episodes following cytotoxic chemotherapy . Fever of any cause developed during 104 out of 191 evaluable episodes . Serum levels of neither cytokine nor CRP were predictive of fever within more than 24 h before its onset . Unlike CRP, both IL-6 and IL-8 serum levels were significantly different between microbiologically documented infections and unexplained fevers . The highest values of IL-6 and IL-8 were observed in episodes of gram-negative bacteremia . Using receiver-operating-characteristic curves, the analysis of cytokine levels measured around the onset of fever indicated that IL-8 is potentially useful for predicting gram-negative bacteremia, with a high negative predictive value of > 90% and a moderate positive predictive value of 50% (sensitivity, 70%; specificity, 91%) . In patients with persistent fever, predictions of further clinical complications, defined as prolonged fever of more than 7 days' duration, pneumonia, shock and/or death due to infection, were best predicted by IL-6 . With an IL-6 cutoff value of 250 pg/ml in samples obtained 8 to 32 h after onset of fever, the positive predictive value was 92%, the negative predictive value 91% (sensitivity, 85%; specificity, 95%) . The positive predictive value of IL-6 in samples obtained another 24 h later from patients still febrile remained > 90%, but the negative predictive value dropped to 47% . In any of the analyses, the predictive values of CRP levels were poor and inferior to either cytokine . These findings may have clinical value in identifying subgroups of patients requiring different therapeutic approaches. Biochim Biophys Acta, 1998 Jul 31, 1393(1), 161 - 5 Novel diglycosyldiacylglycerol from the gram-negative bacterium Deleya marina; Yagi H et al.; A glycosyldiacylglycerol was isolated from the marine bacterium Deleya marina (ATCC 25374) . The structure was determined, mainly by spectral data, to be 1, 2-diacyl-3-O-{alpha-2-amino-2-deoxy-glucopyranose-(1-->4)-O-alpha-idu ronopyranuronic acid}-glycerol . This is, to our knowledge, the first isolation of diglycosyldiacylglycerol containing both iduronopyranuronic acid and 2-amino-2-deoxy-glucopyranose from Gram-negative bacteria. FEBS Lett, 1998 Jul 24, 431(3), 305 - 8 Voltage gating is a fundamental feature of porin and toxin beta-barrel membrane channels; Bainbridge G et al.; Beta-barrel pores are found in outer membrane porins of gram-negative bacteria, bacterial toxins and mitochondrial channels . Apart from the beta-barrel the three groups show no close sequence or structural homology but these pores exhibit symmetrical voltage gating when reconstituted into planar lipid bilayers . The structures of several of these are known and many site-directed mutants have been examined . As a result it seems evident that the gating is a common characteristic of these unrelated large pores and is not generated by specialised structures in the pore lumen. Neuromuscul Disord, 1998 Aug, 8(6), 409 - 15 Molecular genetics and pathogenesis of Friedreich ataxia; Pandolfo M; Friedreich ataxia, the most frequent cause of inherited ataxia, is due in most cases to a large expansion of an intronic GAA repeat, resulting in decreased expression of the target frataxin gene . The autosomal recessive inheritance of the disease gives this triplet repeat mutation some unique features of natural history and evolution . Frataxin is a mitochondrial protein that has homologues in yeast and even in gram negative bacteria . Yeast deficient in the frataxin homologue accumulate iron in mitochondria and show increased sensitivity to oxidative stress . This suggests that Friedreich ataxia is caused by mitochondrial dysfunction and free radical toxicity. Infect Immun, 1998 Sep, 66(9), 4367 - 73 Contribution of regulation by the bvg locus to respiratory infection of mice by Bordetella pertussis; Merkel TJ et al.; Whooping cough is an acute respiratory disease caused by the small, gram-negative bacterium Bordetella pertussis . B . pertussis expresses several factors that contribute to its ability to cause disease . These factors include surface-associated molecules, which are involved in the adherence of the organism to respiratory epithelial cells, as well as several extracellular toxins that inhibit host defenses and induce damage to host tissues . The expression of virulence factors in B . pertussis is dependent upon the bvg locus, which consists of three genes: bvgA, bvgS, and bvgR . The bvgAS genes encode a two-component regulatory system consisting of a sensor protein, BvgS, and a transcriptional activator, BvgA . Upon modification by BvgS, BvgA binds to the promoter regions of the bvg-activated genes and activates transcription . One of the bvg-activated genes, bvgR, is responsible for the regulation of the bvg-repressed genes, the functions of which are unknown . The fact that these genes are regulated by the bvg locus suggests that they play a role in the pathogenesis of the bacterium . In order to evaluate the contribution of bvg-mediated regulation to the virulence of B . pertussis and determine if expression of the bvg-repressed genes is required for the virulence of B . pertussis, we examined the ability of B . pertussis mutants, defective in their ability to regulate the expression of the bvg-activated and/or the bvg-repressed genes, to cause disease in the mouse aerosol challenge model . Our results indicate that the bvgR-mediated regulation of gene expression contributes to respiratory infection of mice. Infect Immun, 1998 Sep, 66(9), 4215 - 21 Hemolytically active (acylated) alpha-hemolysin elicits interleukin-1beta (IL-1beta) but augments the lethality of Escherichia coli by an IL-1- and tumor necrosis factor-independent mechanism; Gleason TG et al.; Many pathogenic Escherichia coli produce the toxin alpha-hemolysin (Hly), and lipopolysaccharide (LPS), interleukin-1 (IL-1), and tumor necrosis factor (TNF) have all been recognized as important effector molecules during infections by gram-negative organisms . Despite the characterization of many in vitro effects of hemolysin, no direct relationship has been established between hemolysin, LPS, proinflammatory cytokine production, and E . coli-induced mortality . Previously, we have shown in vivo that hemolysin elicits a distinct IL-1alpha spike by 4 h into a lethal hemolytic E . coli infection . Using three transformed E . coli strains, WAF108, WAF270, and WAH540 (which produce no Hly {Hlynull}, acylated Hly {Hlyactive}, or nonacylated Hly {Hlyinactive}, respectively), we sought to determine the specific roles of hemolysin acylation, LPS, IL-1, and TNF in mediating the lethality of E . coli infection in mice . WAF270 was 100% lethal in BALB/c, C3H/HeJ, and C57BL/6 mice; in mice pretreated with antibody to the type 1 IL-1 receptor; in type 1 IL-1 receptor-deficient mice; and in dual (type 1 IL-1 receptor-type 1 TNF receptor)-deficient mice at doses which were nonlethal (0%) with both WAF108 and WAH540 . At lethal doses, WAF270 killed by 6 +/- 2.3 h while WAF108 and WAH540 killed at 36 +/- 9.4 and 36 +/- 13.8 h, respectively . These differences in mortality were not due to IL-1 or TNF release, and the enhanced expression of LPS, which corresponded to Hly expression, was not likely the primary factor causing mortality . We demonstrate that bacterial fatty acid acylation of hemolysin is required in order for it to elicit IL-1 release by monocytes and to confer its virulence on E . coli. J Dairy Sci, 1998 Jul, 81(7), 1928 - 35 Effects of a core antigen vaccine against gram-negative bacteria on physiologic and yield parameters of dairy cows during late lactation and the dry period; Scott HM et al.; The objective of the study was to assess the effects of a core antigen vaccine against Gram-negative bacteria on feed consumption, milk yield, somatic cell count, hematologic parameters, and milk progesterone concentrations for dairy cows in late lactation and the dry period . Sixty-eight multiparous Holstein cows from two farms were paired by days in milk and were randomly selected to receive either the vaccine or placebo . Cows received a secondary immunization with the same product (vaccine or placebo) 3 wk following the primary immunization . The physiologic and yield outcomes were measured prior to each immunization, at the time of each immunization, and for one or more periods following each immunization . No significant differences between vaccinated and placebo groups were detected for daily milk weight, daily feed intake, somatic cell score, rectal body temperature, or milk progesterone concentration (pregnant cows) . Cows in the vaccinated group had significant elevations in total blood leukocyte counts following the secondary immunization, which was due to an increase in the neutrophil fraction 24 h postimmunization. Am J Clin Oncol, 1998 Aug, 21(4), 341 - 6 Retrospective analysis of infectious disease in patients who received recombinant human granulocyte-macrophage colony-stimulating factor versus patients not receiving a cytokine who underwent autologous bone marrow transplantation for treatment of lymphoid cancer; Nemunaitis J et al.; Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) significantly shortens the number of days required to achieve an absolute neutrophil count of >500/mm3 after autologous bone marrow transplantation (ABMT); however, the ability of rhGM-CSF to enhance neutrophil and macrophage function in vivo has been incompletely characterized . In this retrospective study, the authors compared the incidence of infection from the day of transplantation to 28 days posttransplantation between two groups of previously studied patients who underwent ABMT at the Fred Hutchinson Cancer Research Center . A control group that received no cytokine was compared with a study group that received rhGM-CSF while participating in phase I, II, or III trials . During the posttransplantation period when both study groups had severe neutropenia, 40% (38 of 95) of control patients were found to have an infection, whereas only 13% (6 of 46) of rhGM-CSF patients developed an infection (p = 0.001) . Most infections occurred before an absolute neutrophil count of > 100/mm3 was achieved . There was a trend toward fewer fungal infections (14% vs . 4%; p = 0.093); gram-negative bacterial infections (6% vs . 0%; p = 0.083); pulmonary infections (12% vs . 2%; p = 0.062); fewer days of amphotericin B (p = 0.0305); and fewer days of intravenous antibiotics (p = 0.0791) in rhGM-CSF-treated patients . These results support in vivo findings that the function-enhancing effect of rhGM-CSF may reduce infection-related complications. J Clin Microbiol, 1998 Sep, 36(9), 2530 - 4 Chronic prosthetic hip infection caused by a small-colony variant of Escherichia coli; Roggenkamp A et al.; From two different specimens of a chronic prosthetic hip infection taken at an interval of 2 months a slow-growing gram-negative bacterium was isolated in pure culture . The strain grew with the typical features of a small-colony variant (SCV) . 16S rRNA sequencing identified the bacterium as Escherichia coli . Biochemical characterization demonstrated multiple phenotypic alterations of a mutant carrying a defect in the heme biosynthetic pathway (Hem-): (i) catalase and nitrate reductase reactions were both negative, (ii) a negative benzidine reaction demonstrated the lack of heme-containing cytochromes, and (iii) growth stimulation under anaerobic conditions as well as gentamicin resistance indicated defective aerobic respiration . PCR and Southern hybridization demonstrated that the mutation of the SCV of E . coli was localized in the hemB gene and was most likely due to a deletion of the hemB gene . On blood agar plates revertants were recognized growing as normal-sized colonies between the dominant small colonies of the strain . Feeding experiments indicated that the revertants but not the small colonies were permeable for hemin . A strong antibody response against the infecting SCV of E . coli was found . To our knowledge, this is the first report of a Hem- E . coli strain as the etiological agent of a chronic bacterial infection. Int J Food Microbiol, 1998 May 26, 41(2), 141 - 54 Components of gut bacteria as immunomodulators; Hamann L et al.; In 1885 Louis Pasteur was the first to propose that the human immune system may be influenced by microorganisms . A large body of data has since been accumulated proving this assumption to be correct . Bacteria constitute the main constituents of the microbial flora of the human digestive tract and compounds of the bacterial cell wall have been shown to play an important role in the interaction of microbes with higher organisms . These components include peptidoglycan (PG) and lipopolysaccharide (LPS) of gram-negative bacteria . Both types of molecules are potent activators of the human immune system and exert their activity through the induction of endogenous mediators which are endowed with biological activity . This review focuses on the structure and activity of LPS and PG and illustrates how these bacterial factors stimulate the immune cells resulting in desired physiological or dramatic pathophysiological responses of the host organism. Am J Respir Crit Care Med, 1998 Aug, 158(2), 610 - 9 Bacterial priming increases lung injury in gram-negative sepsis; Welty-Wolf KE et al.; Sepsis syndrome is a leading cause of acute respiratory distress syndrome (ARDS), but the development of acute lung injury is highly variable for reasons that are poorly understood . We hypothesized that nonlethal systemic exposure to gram-negative bacteria, with its consequent activation of inflammatory processes, would increase functional and structural lung injury on a second exposure to live organisms, as compared with exposure of naive animals . Sixteen adult baboons received 1 to 2 x 10(10) colony-forming-units (cfu)/kg Escherichia coli by intravenous infusion . Eight animals received live bacteria as a single infusion, whereas the other eight received 10% of the total dose as heat-killed organisms (priming dose) 12 h before the live infusion . Pulmonary gas exchange and hemodynamics were monitored for 48 h or until blood pressure could not be maintained . The animals were killed and one lung was processed for electron microscopy and morphometry . Group data were compared through analysis of variance (ANOVA) . The systemic circulatory responses to the bacterial challenge were similar, although less severe shock occurred in primed animals . In contrast, primed animals had increased structural damage involving lung epithelium and endothelium, and showed increased cellularity of the interstitium . The morphologic evidence of increased lung injury in septic animals with prior exposure to heat-killed bacteria suggests that prior activation of systemic inflammatory responses is a contributing factor in the pathogenesis of ARDS. Can J Microbiol, 1998 May, 44(5), 430 - 40 HeLa cells as a model to study the invasiveness and biology of Legionella pneumophila; Garduno RA et al.; HeLa cells were established as a model system to study the invasiveness and biology of Legionella pneumophila . In this model, invasion could be distinguished from adherence; virulent strains of L . pneumophila were adherent and invasive, whereas nonvirulent strains were adherent but poorly invasive . Invasion was rapid and did not require de novo bacterial protein synthesis, suggesting that the invasion factor is constitutively expressed by virulent strains . Entry into HeLa cells required actin polymerization and an intact microtubule cytoskeleton and was only moderately inhibited by the presence of 100 mM glucose or galactose . Intracellular replication of virulent L . pneumophila took place in ribosome-studded complex endosomes and led to the formation of free bacteria-laden vesicles presumably released from lysed HeLa cells . These free vesicles (referred to as mature vesicles) were isolated in continuous density gradients of Percoll . The bacteria contained in the isolated mature vesicles had a unique envelope structure and were highly adherent to HeLa cells, characteristics that correlated with a bright red appearance after the Gimenez stain (Gimenez positive) . Plate-grown legionellae and replicating legionellae, harboured in complex endosomes, displayed a typical Gram-negative envelope and stained green after the Gimenez stain (Gimenez negative) . Chronically infected cultures of HeLa cells were also established that may be a useful tool for studying long-term interactions between virulent L . pneumophila and mammalian cells . HeLa cells constitute a valuable model system that offers unique opportunities to study parasite-directed endocytosis, as well as stage specific-parasite interactions. Am J Respir Cell Mol Biol, 1998 Aug, 19(2), 177 - 201 Collectins and pulmonary host defense; Crouch EC; The surfactant-associated proteins SP-A and SP-D are members of a family of collagenous host defense lectins, designated collectins . There is increasing evidence that these pulmonary epithelial-derived proteins are important components of the innate immune response to microbial challenge, and that they participate in other aspects of immune and inflammatory regulation within the lung . The collectins bind to glycoconjugates and/or lipid moieties expressed by a wide variety of microorganisms and certain other organic particles in vitro . Although binding may facilitate microbial clearance through aggregation or other direct effects on the organism, SP-A and SP-D also have the capacity to modulate leukocyte function and, in some circumstances, to enhance their killing of microorganisms . The biologic activity of cell wall components, such as gram-negative bacterial polysaccharides, may be altered by interactions with collectins . Complementary or cooperative interactions between SP-A and SP-D could contribute to the efficiency of this defense system . Collectins may play particularly important roles in settings of inadequate or impaired specific immunity . Acquired or genetic alterations in the levels of active proteins within the airspaces and distal airways may increase susceptibility to infection. J Surg Res, 1998 Jun, 77(1), 29 - 34 Effects of endotoxin challenge on hepatic amino acid transport during cancer; Easson AM et al.; BACKGROUND: The hepatic uptake of amino acids is increased in both sepsis and cancer, and this response appears to be both global and essential in the catabolic host . Because immunocompromised cancer patients are susceptible to episodes of gram-negative sepsis, we examined the capacity of hepatocytes from normal and tumor-influenced livers to respond to the additional challenge of endotoxemia via increases in the Na+-dependent uptake of glutamine and zwitterionic amino acids by System N and System A, respectively . MATERIALS AND METHODS: Fischer 344 rats were implanted with methylcholanthrene-induced fibrosarcomas . Control rats were sham-operated and pair-fed . Animal pairs (tumor burden = 8-32% carcass weight) were injected intraperitoneally with either Escherichia coli endotoxin (10 mg/kg) or PBS, and after 4 h, hepatocytes were isolated from the livers of the animals via collagenase perfusion and placed in primary culture . Three hours later, amino acid transport rates were measured using radiolabeled glutamine for System N and alpha-methylaminoisobutyric acid (MeAIB), a nonmetabolizable substrate specific for System A . RESULTS: Cancer-independent of tumor size-and endotoxin each elicited similar 1.5- to 2-fold inductions of System N activity . When combined, their effects were additive rather than synergistic . In contrast, endotoxin induced an insignificant increase in System A activity, whereas cancer stimulated this carrier 2-fold in either the absence or the presence of endotoxin . CONCLUSIONS: The primary glutamine and alanine carriers in hepatocytes are differentially influenced during catabolic states, and the tumor-influenced liver is competent to further increase glutamine uptake in response to additional catabolic insults . Clin Exp Immunol, 1998 Jul, 113(1), 39 - 47 N-formyl-methionyl-leucyl-phenylalanine (fMLP) inhibits tumour necrosis factor-alpha (TNF-alpha) production on lipopolysaccharide (LPS)-stimulated human neutrophils; Vulcano M et al.; During gram-negative infections bacterial components, such as LPS and formylated peptides, exert profound physiological effects on polymorphonuclear neutrophils (PMN) resulting in increased neutrophil effector activities, including the generation of oxidative metabolites, degranulation, phagocytosis and cytokine release . There is not enough evidence about the relationships between LPS and formylated bacterial peptides in the triggering and regulation of the immune inflammatory response . In this study, we present evidence indicating that pretreatment of human PMN with a prototype formylated peptide such as fMLP results in the inhibition of TNF-alpha secretion, a key molecule that plays a central role in the pathogenesis of septic shock . This inhibitory effect of fMLP does not appear to alter the expression of LPS receptors or the transcriptional pathway of the TNF-alpha mRNA, but instead, fMLP reduces the expression of the membrane form of TNF-alpha on the PMN surface . These findings indicate that fMLP, a typical proinflammatory agent, could play, at least in determined conditions, an anti-inflammatory role. Digestion, 1998 Jul-Aug, 59(4), 284 - 97 Bacterial lipopolysaccharide protects gastric mucosa against acute injury in rats by activation of genes for cyclooxygenases and endogenous prostaglandins; Konturek PC et al.; Lipopolysaccharides (LPS) derived from gram-negative bacteria were reported to impair gastrointestinal mucosal integrity, but the results obtained are controversial . This study was undertaken to determine the effects of short-term administration of LPS on gastric secretion and gastric damage induced by 100% ethanol and to assess the role of the gene expression of two isoforms of cyclooxygenase (COX), constitutive (COX-1) and inducible (COX-2), and endogenous prostaglandins (PG) on these effects of LPS . Fasted rats received vehicle (control) or LPS (0.1-40 mg/kg i.g . or i.p.) without or with pretreatment with nonselective inhibitors of COX activity, indomethacin (5 mg/kg i.p.) and meloxicam (2 mg/kg i.g.), or the selective COX-2 inhibitor NS-398 (10 mg/kg i.g.), followed by intragastric application of 100% ethanol . The area of gastric lesions was determined by planimetry, gastric blood flow (GBF) was measured by the H2-gas clearance technique, mucosal PGE2 generation was measured by radioimmunoassay, and expression of COX-1 and COX-1 mRNA was determined by reverse transcription polymerase chain reaction (RT-PCR), quantitative RT-PCR with {32P}dCTP and immunohistochemistry . LPS applied intraperitoneally in various doses (0.1-10 mg/kg), dose dependently inhibited gastric acid and pepsin secretion and significantly reduced the area of gastric lesions induced by ethanol, and this was accompanied by an attenuation of the ethanol-induced fall in GBF and increased mucosal generation of PGE2 . LPS applied in higher doses, such as 20 or 40 mg/kg, that caused systemic hypotension failed to protect the mucosa against 100% ethanol . Suppression of mucosal PGE2 generation by indomethacin or meloxicam, significantly reduced the inhibitory action of LPS on gastric secretion and abolished LPS-induced gastroprotection and elevation of GBF . NS-398 did not influence PGE2 generation, but significantly attenuated the protection and hyperemia induced by LPS suggesting that COX-2-derived products play an important role in gastroprotection . The expression of COX-1 mRNA, as determined by RT-PCR, quantitative RT-PCR and immunohistochemistry was found in intact gastric mucosa and after LPS administration . In contrast, the expression of COX-2 mRNA was undetectable in intact gastric mucosa but appeared in this mucosa 2, 4 and 8 h after LPS administration . COX-2 mRNA was not detected in rats treated with ethanol but, when LPS was applied before ethanol, the enhanced expression of COX-2 was detected without affecting COX-1 mRNA expression . We conclude that acute parenteral LPS affords gastroprotection against ethanol-damage through an increase in gastric microcirculation and overexpression of COX-2 and enhanced endogenous PG release. J Periodontal Res, 1998 May, 33(4), 179 - 86 Clonal analysis by ribotyping of Fusobacterium nucleatum isolates obtained from healthy young adults with optimal plaque control; Suchett-Kaye G et al.; Fusobacterium nucleatum is a Gram-negative anaerobic rod implicated in the pathogenesis of periodontal disease . However, this organism has also been frequently identified in high numbers in healthy adults . These observations suggest that the species may comprise different clonal types, some of which may participate in disease . The purpose of the present investigation was to use restriction endonuclease analysis (REA) and ribotyping to characterize F . nucleatum clonal types isolated from healthy young adults with optimal plaque control and investigate the stability of some of these clonal types . A group comprising 11 dental students and 11 dental outpatients with optimal plaque control was sampled . Clonal stability was investigated by sampling the dental student group at baseline and at 16 months . One hundred and thirty-two clinical isolates of F . nucleatum were successfully recovered from 15/22 individuals . For the positive subjects, 29 different clonal types were identified by REA and ribotyping, each subject and site being colonized by 1-4 clonal types . For the dental students, 9 and 15 different clonal types were identified at baseline and 16 months, respectively . None of the students harboured identical clonal types at both sampling times . Our results show that ribotyping is a useful technique for monitoring the distributions of F . nucleatum clonal types and indicate that healthy individuals with optimal plaque control can be colonized by more than one F . nucleatum clonal type and that these clonal types appear to be unstable. Appl Environ Microbiol, 1998 Aug, 64(8), 3029 - 35 Purification and characterization of a high-molecular-weight insecticidal protein complex produced by the entomopathogenic bacterium photorhabdus luminescens Bowen DJ, Ensign JC. Photorhabdus luminescens is a gram-negative enteric bacterium that is found in association with entomopathogenic nematodes of the family Heterorhabditidae . The nematodes infect a variety of soil-dwelling insects . Upon entering an insect host, the nematode releases P . luminescens cells from its intestinal tract, and the bacteria quickly establish a lethal septicemia . When grown in peptone broth, in the absence of the nematodes, the bacteria produce a protein toxin complex that is lethal when fed to, or injected into the hemolymph of, Manduca sexta larvae and several other insect species . The toxin purified as a protein complex which has an estimated molecular weight of 1,000,000 and contains no protease, phospholipase, or hemolytic activity and only a trace of lipase activity . The purified toxin possesses insecticidal activity whether injected or given orally . Analyses of the denatured complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed it to be composed of several protein subunits ranging in size from 30 to 200 kDa . The complex was further separated by native gel electrophoresis into three components, two of which retained insecticidal activity . The purified native toxin complex was found to be active in nanogram concentrations against insects representing four orders of the class Insecta. Shock, 1998 Jul, 10(1), 37 - 42 Nitric oxide production in experimental gram-negative infection: studies with cytokine receptor-deficient mice; Le Roy D et al.; Overproduction of nitric oxide (NO) upon expression of inducible NO synthase (iNOS) may be responsible for refractory hypotension in septic shock . Whereas high levels of NOS activity have been documented in experimental models of endotoxemia or intravenous challenge with Escherichia coil, much less is known concerning tissue models of Gram-negative infection . We examined NO production (measured as the accumulation of plasma NO3- + NO2-) in a murine model of Gram-negative peritonitis . Plasma NO3- + NO2- increased progressively from 25 microM to peak levels of 50-150 microM 24 h after intraperitoneal challenge with E . coli 0111:B4, similar to values reported for septic shock patients . Treatment of infected mice with NG-monomethyl-L-arginine, an inhibitor of NOS activity, resulted in the efficient inhibition of NO3- + NO2- production . In order to evaluate the roles of interferon-gamma (IFN-gamma) and tumor necrosis factor (TNF-alpha) in the induction of NO synthesis in murine peritonitis, mice deficient in the respective cytokine receptors were studied . In control in vitro experiments, macrophages from IFN-gammaR- or TNFR55-deficient mice, while failing to respond to IFN-gamma or TNF-alpha, respectively, produced high levels of NO under appropriate stimulation . When challenged intraperitoneally with E . coli, IFN-gammaR- or TNFR55-deficient mice exhibited similar levels of bacteremia and NO production as their wild-type controls . These data thus suggest that enhanced NO production during focal Gram-negative infection may occur in the absence of signaling through either IFN-gammaR or TNFR55. EMBO J, 1998 Aug 3, 17(15), 4511 - 26 Protein domains and conformational changes in the activation of RepA, a DNA replication initiator; Giraldo R et al.; RepA is the DNA replication initiator protein of the Pseudomonas plasmid pPS10 . RepA has a dual function: as a dimer, it binds to an inversely-repeated sequence acting as a repressor of its own synthesis; as a monomer, RepA binds to four directly-repeated sequences to constitute a specialized nucleoprotein complex responsible for the initiation of DNA replication . We have previously shown that a Leucine Zipper-like motif (LZ) at the N-terminus of RepA is responsible for protein dimerization . In this paper we characterize the existence in RepA of two protein globular domains C-terminal to the LZ . We propose that dissociation of RepA dimers into monomers results in a conformational change from a compact arrangement of both domains, competent for binding to the operator, to an extended species that is suited for iteron binding . This model establishes the structural basis for the activation of DNA replication initiators in plasmids from Gram-negative bacteria. J Biol Chem, 1998 Aug 7, 273(32), 20285 - 91 CD14-dependent endotoxin internalization via a macropinocytic pathway; Poussin C et al.; Gram-negative bacterial endotoxin (a lipopolysaccharide (LPS)) specifically binds to CD14, a glycosylphosphatidyl inositol (GPI)-anchored surface myeloid glycoprotein . This interaction leads to cell activation, but it also promotes LPS internalization and detoxification . In this work, we investigated the route of LPS and CD14 internalization and the relevance of CD14 GPI anchor in the endocytic pathway . In promonocytic THP-1 cells transfected with a GPI or a chimeric integral form of CD14, we showed by differential buoyancy in sucrose density gradients that these two forms of CD14 were sorted to different plasma membrane subdomains . However, both forms of CD14 associated preferentially with the same surface microfilament-enriched microvilli or ruffles . Electron microscopic studies indicated that CD14 internalized via macropinocytosis, a process resembling that of phagocytosis, different from "classical" receptor-mediated endocytic pathways, such as clathrin-coated pits or caveolae . With cell warming, the CD14-enriched ruffles fused and formed large vesicles . Later, these vacuoles made stacks and condensed into phago-lysosomes . CD14 was specifically associated with all of these structures . Radiolabeled LPS internalization paralleled CD14 internalization . Confocal microscopic studies confirmed the co-localization of LPS and CD14 both at the cell surface and in endosomal compartments . The microfilament-disrupting, macropinocytosis blocking agent cytochalasin D inhibited LPS and CD14 internalization but did not prevent LPS-dependent activation, indicating that these two processes are dissociated. J Biol Chem, 1998 Aug 7, 273(32), 20185 - 8 Lipopolysaccharide mediates endothelial apoptosis by a FADD-dependent pathway; Choi KB et al.; Endothelial cells play a pivotal role in the inflammatory process by coordinating the recruitment of inflammatory cells to sites of tissue injury . Lipopolysaccharide (LPS) activates many of the proinflammatory and procoagulant responses of endothelial cells, and endothelial injury is thought to play a crucial role in the pathogenesis of septic shock due to Gram-negative bacteria . The receptor used by LPS to signal endothelial responses has not been identified . It is also not known how LPS induces endothelial injury/death . In this study, we demonstrate that LPS mediates endothelial apoptosis by a FADD-dependent pathway . FADD is a death domain-containing protein that binds to certain members of the tumor necrosis factor receptor family, namely TNFR1, Fas, and DR3 . However, none of these receptors appear to be involved in LPS-mediated death, suggesting that LPS may utilize a novel death domain-containing protein to transduce a death signal. Int J Artif Organs, 1998 May, 21(5), 269 - 73 Polymyxin-B stimulates tumor necrosis factor-alpha production by human peripheral blood mononuclear cells; Jaber BL et al.; Gram-negative bacterial lipopolysaccharide (LPS) is a well known stimulus for cytokine production, particularly interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF alpha) . Polymyxin B (PMX-B) is a cationic polypeptide that binds to LPS, neutralizing its biological effects . PMX-B also disrupts gram-negative bacterial cell membrane phospholipids but is highly toxic to mammalian cells, therefore is of limited use . PMX-B is used as additive to media, as a way to handle LPS contamination . To derive benefit from the ability of PMX-B to neutralize lipid A in vivo while avoiding its systemic toxicity, PMX-B was covalently bound to polystyrene-derivative fibers, creating a hemoperfusion column (PMX-F) for the selective removal of circulating ET . In vitro PMX-F hemoperfusion studies have demonstrated effective ET removal, using either the Limulus amebocyte lysate assay or TNF alpha production by peripheral blood mononuclear cells (PBMC) as an index of ET removal . However, the question whether PMX-B itself could stimulate human PBMC to produce cytokines has not been adequately addressed . We examined the effect of increasing concentrations of PMX-B on cytokine production by PBMC in vitro . PBMC harvested from healthy volunteers were incubated for 24 hours at 37 degrees C with control (tissue culture media RPMI), or 5 microg/ml, 10 microg/ml, 20 microg/ml or 100 microg/ml PMX-B . At the end of 24 hours, PBMC were subjected to three freeze-thaw cycles, and total TNF alpha production (pg/2.5x10(6) PBMC) was measured by radioimmunoassay . Total TNF alpha production by PBMC was 163 +/- 3 pg, 171 +/- 9 pg, 164 +/- 4 pg, 323 +/- 63 pg and 331 +/- 58 pg, in the control, PMX-B 5 microg/ml, 10 microg/ml, 20 microg/ml and 100 microg/ml conditions, respectively . Compared to controls (RPMI), the percentage increase in TNF alpha production by PBMC was 5 +/- 6% (P=0.23), 1 +/- 3% (P=0.45), 99 +/- 40% (P=0.03) and 103 +/- 36% (P=0.02) in the presence of 5 microg/ml, 10 microg/ml, 20 microg/ml and 100 microg/ml of PMX-B, respectively . Furthermore, total TNF alpha production correlated significantly with increasing concentrations of PMX-B (R=0.53, P=0.007) . We conclude that the use of PMX-B in in vitro studies as an LPS-neutralizing agent, or in the experimental treatment of endotoxic or septic shock can lead to erroneous interpretations of cytokine production by PBMC, and should be used cautiously in in vitro systems at high concentrations. Extremophiles, 1997 May, 1(2), 67 - 73 Stetteria hydrogenophila, gen . nov . and sp . nov., a novel mixotrophic sulfur-dependent crenarchaeote isolated from Milos, Greece; Jochimsen B et al.; A new hyperthermophilic, strictly anaerobic crenarchaeote, Stetteria hydrogenophila DSM11227 representing a new genus within the family of Desulfurococcaceae, was isolated from the sediment of a marine hydrothermal system at Paleohori Bay in Milos, Greece . Cells are gram-negative irregular and disc-shaped cocci, 0.5-1.5 microm in diameter, which are flagellate and can form cytoplasmatic protrusions up to 2 microm in length . The strain grew optimally at 95 degrees C at pH 6.0 and at a NaCl concentration of 3% . The organism grew mixotrophically on peptide substrates . It required elemental sulfur as an external electron acceptor, and in addition, its growth was completely dependent on the presence of molecular hydrogen . Sulfur could be replaced by thiosulfate . H2S, CO2, acetate, and ethanol were identified as products of metabolism . The G + C content of DNA was 65 mol% . Analysis of its phylogenetic position by sequence analysis of 16S rRNA placed this organism in the family of Desulfurococcaceae . The dependence of this organism on both hydrogen and sulfur during growth on peptide substrates distinguishes Stetteria from all previously described species of Crenarchaeota. Medicina (B Aires), 1998, 58(1), 61 - 4 {Human polymorphonuclear neutrophils (PMN) induce lipopolysaccharide (LPS) liberation from gram-negative bacteria}; Breyer I et al.; Bacterial lipopolysacharride (LPS) is the major membrane component of Gram negative bacteria . It is a potent pleiotropic stimulus for the immune system frequently associated with septic syndrome or septic shock . The detoxification of LPS in Gram negative sepsis is one of the important problems to resolve in clinical treatments . In this study we compare the capacity of polymorphonuclear neutrophils (PMN) in LPS detoxification in two different situations: a) when LPS is offered to PMN as an isolated molecule; b) when the LPS offered is part of the whole Gram negative bacteria (E . coli 0111:B4) . Our results show that PMN are able to inhibit the capacity of LPS to produce TNF-alpha . However, when whole bacteria, instead of LPS, are incubated with PMN, an enhancement in the production of tumor necrosis factor alpha (TNF-alpha) is observed . The bacterial overburden of PMN is not the reason for the spread of LPS after PMN incubation . Our conclusion is that PMN have a dual capacity to deal with LPS, either inactivating or releasing it depending on how it is offered. Infect Immun, 1998 Aug, 66(8), 3545 - 51 Organization of Escherichia coli O157 O antigen gene cluster and identification of its specific genes; Wang L et al.; The O157:H7 clone of Escherichia coli, which causes major, often prolonged outbreaks of gastroenteritis with hemolytic-uremic syndrome (HUS) such as those in Japan, Scotland, and the United States recently, is thought to be resident normally in cattle or other domestic animals . This clone is of major significance for public health and the food industry . We have developed a fast method for sequencing a given O antigen gene cluster and applied it to O157 . The O157 O antigen gene cluster is 14 kb in length, comprising 12 genes and a remnant H-repeat unit . Based on sequence similarity, we have identified all the necessary O antigen genes, including five sugar biosynthetic pathway genes, four transferase genes, the O unit flippase gene, and the O antigen polymerase gene . By PCR testing against all 166 E . coli O serogroups and a range of gram-negative bacterial strains, including some that cross-react serologically with E . coli O157 antisera, we have found that certain O antigen genes are highly specific to O157 E . coli . This work provides the basis for a sensitive test for rapid detection of O157 E . coli . This is important both for decisions on patient care, since early treatment may reduce the risk of life-threatening complications, and for detection of sources of contamination . The method for fast sequencing of O antigen gene clusters plus an ability to predict which genes will be O antigen specific will enable PCR tests to be developed as needed for other clones of E . coli or, once flanking genes are identified, clones of any gram-negative bacterium. FEMS Microbiol Lett, 1998 Jun 15, 163(2), 223 - 8 On the origin of membrane vesicles in gram-negative bacteria; Zhou L et al.; It is proposed that the genesis of extracellular membrane vesicles in Gram-negative bacteria is a result of cell wall turnover . Peptidoglycan turnover would cause a turgor on the outer membrane, causing the outer membrane to bulge and finally bleb . Mechanical motion would then shear the blebs into the culture medium. QJM, 1998 Apr, 91(4), 265 - 77 Evolving strategies in the treatment of sepsis and systemic inflammatory response syndrome (SIRS); Horn KD; In recent years, much basic science research has investigated the predisposing factors, initiation, propagation, and resolution of Gram-negative sepsis, endotoxaemic shock, and the newly defined entity of systemic inflammatory response syndrome (SIRS) . A major cause of morbidity and mortality in the post-surgical, neonatal, and geriatric hospital population, sepsis has proven itself notoriously resistant to classical modes of therapy, including antibiotics, fluid/pressor and respiratory support . Recently, the widespread nosocomial isolation of new antibiotic-resistant strains of endotoxin-producing bacteria has further complicated management . For these reasons, there is much interest in alternative treatment modalities which focus upon the endotoxin molecule itself and the systemic inflammatory response it provokes via the cytokine, complement, and coagulation cascades . In this review, recent experimental approaches to the therapy of sepsis and SIRS are discussed in light of each step in the complex inflammatory cascade and in comparison to traditional approaches to prevention and therapy of Gram-negative bacteraemia and septic shock. J Leukoc Biol, 1998 Jul, 64(1), 25 - 32 LPS-binding proteins and receptors; Fenton MJ et al.; Macrophage activation by gram-negative lipopolysaccharide (LPS) has been extensively studied in an attempt to define the mechanisms that underlie innate immunity against bacterial pathogens . Dysregulation of these same mechanisms contributes to the pathophysiological consequences of bacterial sepsis . The biological actions of LPS are mediated, at least in part, by both LPS-binding proteins and LPS receptors . Several LPS receptors (CD14, the macrophage scavenger receptor, and the beta2 integrins), as well as the serum LPS-binding protein LBP, have been cloned and studied in detail . In addition, insights gained through the use of LPS antagonists have led to a better understanding of a molecule believed to function in conjunction with LPS receptors to transduce signals from the membrane to the cytosol . More recently, the use of knockout mice has greatly expanded our knowledge of the biology of LPS receptors and binding proteins . This review will summarize various phenotypes of mice that lack genes encoding CD14, the scavenger receptor, and LBP . These knockout mice have revealed several unexpected features of LPS action in vivo . Together, these animal models may provide a means to develop and evaluate novel therapeutic approaches to the control of endotoxin shock. Surgery, 1998 Jul, 124(1), 73 - 8 Impact of altered aminoglycoside volume of distribution on the adequacy of a three milligram per kilogram loading dose . Critical Care Research Group; Dorman T et al.; BACKGROUND: Sepsis is associated with an increased volume of distribution for aminoglycoside antibiotics . As a result of this increased volume of distribution, 2 mg/kg loading doses have previously been shown to be ineffective in producing adequate aminoglycoside peak plasma levels in critically ill patients . The main objective of this pharmacokinetic observational study was to determine the adequacy of a 3 mg/kg loading dose of gentamicin or tobramycin in attaining an initial peak level of 8 micrograms/ml or greater . METHODS: Fifty-three consecutive patients given gentamicin or tobramycin for documented or suspected life-threatening gram-negative infections were enrolled . Loading doses of either aminoglycoside were administered during 30 minutes, and a peak level was obtained 1 hour after completed infusion . RESULTS: The patient's mean age was 61 +/- 2 years, with a male/female ratio of 33:20 . The loading dose of 3 mg/kg produced 1-hour peak aminoglycoside levels greater than 8 micrograms/ml in only 50% of the patients studied . The calculated aminoglycoside volume of distribution was increased by 34% . CONCLUSIONS: An aminoglycoside loading dose of 3 mg/kg is inadequate in critically ill patients undergoing operation . The documented increase in volume of distribution is principally responsible for the inadequacy of this dose . Future studies should use a 4 mg/kg loading dose to maximize aminoglycoside bactericidal activity. Zh Mikrobiol Epidemiol Immunobiol, 1998 Mar-Apr, (2), 18 - 21 {Development of a test system for detection of anti-endotoxic immunity in young children, healthy donors and some groups of therapeutic patients}; Uvitskii AIu et al.; The content of antibodies to soluble lipid A detritus was studied with the use of the enzyme immunoassay techniques . Some regularities of anti-endotoxic immunity were established: the elevated level of anti-lipid A antibodies in chronic bronchial tree diseases of bacterial etiology . On the other hand, cases of severe purulent septic infections in young children were found to be accompanied by a considerable decrease in the titer of anti-endotoxic antibodies . The approaches to the therapy of diseases caused by Gram-negative bacteria by means of specific immunoglobulins are discussed. J Periodontol, 1998 Jun, 69(6), 686 - 97 Immunization with Porphyromonas gingivalis cysteine protease: effects on experimental gingivitis and ligature-induced periodontitis in Macaca fascicularis; Moritz AJ et al.; Targeting bacterial virulence factors such as proteases for immunization may hold the key to limiting or preventing loss of attachment and alveolar bone in periodontal disease . This study examined the clinical, microbiological, and immununological responses following active immunization with a purified Porphyromonas gingivalis cysteine protease (porphypain-2) in the nonhuman primate (Nhp) Macaca fascicularis . One group of Nhp was immunized with porphypain-2 antigen while control Nhp received placebo injections . All Nhp were subjected to experimental gingivitis followed by ligature-induced periodontitis in a split-mouth design . An enzyme-linked immunosorbent assay demonstrated that immunization elicited a significantly elevated and specific IgG antibody response to both whole cell P . gingivalis (36-fold) and to porphypain-2 (194-fold) . Checkerboard hybridization DNA analysis of subgingival plaque from ligated sextants demonstrated that 25% more Gram-negative anaerobic species became significantly elevated from baseline and at earlier timepoints in the control group than in the immununized group . Immunization with this protease did not suppress the emergence of P . gingivalis . Clinical indices showed few changes related to immunization . Alveolar bone density changes demonstrated a highly significant loss in ligated sextants compared to non-ligated sextants within the control group (P < 0.001), and a smaller but significant difference within the immunized group (P = 0.043) . Comparison of ligated sextants only demonstrated more bone loss in the control group versus the immunized group (-13.07+/-9.51 versus -9.41+/-6.18; computer-assisted densitometric image analysis units +/- SD); the difference approached, but did not reach, significance . The results suggest that porphypain-2 may contribute to the pathogenic potential of the subgingival plaque microbiota in the Nhp model of ligature-induced periodontitis, and that active immunization with porphypain-2 appeared capable of altering this pathogenic response. Intensive Care Med, 1998 May, 24(5), 438 - 45 Prognostic importance of gram-negative intestinal colonization preceding pancreatic infection in severe acute pancreatitis . Results of a controlled clinical trial of selective decontamination; Luiten EJ et al.; OBJECTIVES: To establish, firstly, whether gram-negative (re)-colonization of the gut leads to an increased risk of gram-negative pancreatic infections and whether this event is time-related and, secondly, whether the difference in the quantity and quality of micro-organisms colonizing the digestive tract influences morbidity and mortality . DESIGN: Prospective analysis of the results of systematic semi-quantitative cultures of several body areas taken from patients with severe acute pancreatitis, during a controlled multicenter trial of adjuvant selective decontamination . SETTING: Surgical intensive care units of 16 hospitals . PATIENTS: A total of 2,159 semi-quantitative cultures from the oropharynx, rectum and pancreatic tissues taken from 90 patients were analyzed . Interventions: Surveillance cultures from the oropharynx and rectum were taken on admission and repeated twice weekly and from the (peri)-pancreatic devitalized tissues (i . e . necrosis) at every relaparotomy and from drainage . MEASUREMENTS AND RESULTS: All gram-negative pancreatic infections were preceded by intestinal colonization with the same micro-organisms . The risk of developing a pancreatic infection following gram-negative intestinal colonization (15/42 patients) was significantly higher as compared to patients without gram-negative colonization (0/10 patients) (p < 0.001) or to patients in whom E . coli was the only intestinal micro-organism cultured (0/30 patients) (p < 0.001) . The occurrence of intestinal E . coli did not increase the risk of pancreatic infection . Gram-negative colonization of the rectum and oropharynx significantly correlated with the later development of pancreatic infection: relative risks 73.7 (p < 0.001) and 13.6 (p < 0.001), respectively . However, when both areas were evaluated simultaneously, the rectum was more significant (p < 0.001) . The severity of intestinal intestinal colonization until the moment of pancreatic infection showed an increase in time in all 15 patients . In 11 of 15 patients (73%) these infections occurred within 1 week following the first isolation from the digestive tract . Gram-negative intestinal colonization was associated with a 3.7 fold increased mortality risk (p = 0.004) . CONCLUSIONS: Gram-negative intestinal colonization, E . coli excepted, is an early prognostic parameter in patients in whom pancreatic infection has not yet occurred and represents a significantly increased risk of pancreatic infections and mortality. J Bacteriol, 1998 Jul, 180(14), 3541 - 7 Expression of a gene for a porin-like protein of the OmpA family from Mycobacterium tuberculosis H37Rv; Senaratne RH et al.; An open reading frame in the genomic database of Mycobacterium tuberculosis H37Rv was identified as having homology with an outer membrane protein . We found that the gene specified a protein belonging to the OmpA family, which includes some porins of gram-negative organisms . The gene was amplified by PCR and cloned into Escherichia coli . Overexpression of the gene was toxic to the host, but limited amounts could be purified from cells before growth ceased . A truncated gene devoid of the code for a presumed signal sequence was well expressed, but the protein had no pore-forming activity in the liposome swelling assay . However, the intact protein, OmpATb, behaved as a porin of low specific activity, with a pore diameter of 1.4 to 1.8 nm, and was also active in planar lipid bilayers, showing a single-channel conductance of 700 pS . The protein had a molecular mass of about 38 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis . A polyclonal rabbit antiserum raised to the truncated protein recognized a protein of similar molecular mass in detergent extracts of broken M . tuberculosis cells . Reverse transcription-PCR confirmed that the gene for OmpATb was expressed in M . tuberculosis cells growing in culture . Comparison of the purified protein with that in the detergent-extracted preparation using liposomes and planar lipid bilayers showed that the two materials had similar pore-forming properties . OmpATb is different from either of the mycobacterial porins described so far . This is the first report of a porin-like molecule from M . tuberculosis; the porin is likely to be important in controlling the access of hydrophilic molecules to the bacterial cell. FEMS Immunol Med Microbiol, 1998 May, 21(1), 79 - 87 Effect of O-antigenic polysaccharide of Escherichia coli on endotoxin neutralizing activity of lysozyme; Liang AH et al.; Endotoxemia is considered to be associated with the high mortality of gram-negative septic patients . Increasing evidence shows that beta-lactam antibiotics have a propensity to induce endotoxin release from the bacterial outer membrane while killing bacteria . We have recently found that egg white lysozyme (EW-LZM) shows strong inhibition of beta-lactam induced bacteriolysis and lipopolysaccharide (LPS) release from Escherichia coli O111, resulting in reduction of the LPS-initiated inflammatory response . In this study, we compared the effect of EW-LZM on E . coli J5, which possesses rough-type LPS (RaLPS), in order to demonstrate the effect of O-antigenic polysaccharide on endotoxin neutralizing activity of EW-LZM and on inhibition of beta-lactam induced lysis by LZM . Both of the beta-lactam induced bacterial lysis and subsequent LPS release were almost completely inhibited by EW-LZM . The effect was more potent than that of wild-type LPS as assessed by released LPS concentration and LPS induced cytokine syntheses . In addition, EW-LZM was effective against lethal infection of E . coli J5 in cyclophosphamide induced leukopenic mice . These facts strongly suggested that O-antigenic polysaccharide negatively modulates LPS neutralizing activity of EW-LZM. Biochim Biophys Acta, 1998 Jun 29, 1385(2), 353 - 66 The pyruvate dehydrogenase multi-enzyme complex from Gram-negative bacteria; de Kok A et al.; Pyruvate dehydrogenase multi-enzyme complexes from Gram-negative bacteria consists of three enzymes, pyruvate dehydrogenase/decarboxylase (E1p), dihydrolipoyl acetyltransferase (E2p) and dihydrolipoyl dehydrogenase (E3) . The acetyltransferase harbors all properties required for multi-enzyme catalysis: it forms a large core of 24 subunits, it contains multiple binding sites for the E1p and E3 components, the acetyltransferase catalytic site and mobile substrate carrying lipoyl domains that visit the active sites . Today, the Azotobacter vinelandii complex is the best understood oxo acid dehydrogenase complex with respect to structural details . A description of multi-enzyme catalysis starts with the structural and catalytic properties of the individual components of the complex . Integration of the individual properties is obtained by a description of how the many copies of the individual enzymes are arranged in the complex and how the lipoyl domains couple the activities of the respective active sites by way of flexible linkers . These latter aspects are the most difficult to study and future research need to be aimed at these properties. Rom J Physiol, 1997 Jan-Dec, 34(1-4), 75 - 82 Effects of electrolytic bilateral symmetric lesions of the arcuate nucleus on the phagocytic activity and on the phagocytic response in rats; Felegean A et al.; Previous researches of Cluj-Napoca laboratories of Physiology (Benetato, Baciu et al., 1945, 1946, 1947) demonstrated that direct electrical stimulation of the tubero-mammillary area in dogs increases, in the following hours, the blood polymorphonuclears phagocytic activity . By contrast, electrical damage of the same region produces a depression of the basal phagocytic activity and a blocking of the phagocytic response (Baciu et al., 1958, 1988) . In the present research we assumed there is a stimulating effect of the arcuate nucleus, located in this area, on the phagocytic activity of blood neutrophils . We used an anodal current to stereotaxically induce lesion of the arcuate nucleus in six rats . A control group of six animals was used . Five days later, phagocytic response was induced with a Gram negative bacterial extract given i.v . The results demonstrated a decrease of the phagocytic activity from 164.31 +/- 17 bacteria engulfed by 100 neutrophils in controls, to 138 +/- 12.8 in the lesioned group p < 0.05 . Phagocytic response after five hours appears depressed in the lesioned group (138 +/- 12.8 to 156.25 +/- 13.3, p < 0.05) . Similar results were obtained after 24 hours . In control animals the response is very significant after 5 and 24 hrs., respectively, (p < 0.001) . In conclusion, the arcuate nucleus is moderately involved in sustaining the basal phagocytic activity of blood neutrophils . It has an important role in phagocytic response. J Infect Dis, 1998 Jul, 178(1), 270 - 3 Circulating endotoxin during initial antibiotic treatment of severe gram-negative bacteremic infections; Maury E et al.; The impact of antibiotics on total endotoxemia and circulating tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8 in 18 patients with severe bacteremic sepsis or septic shock due to gram-negative species was investigated . Endotoxemia, TNF-alpha, IL-6, and IL-8 were assayed before (H0) and 1 h (H1) and 4 h (H4) after the first antibiotic infusion . Endotoxemia decreased from H0 (median, 0.4 EU/mL; interquartile interval, 0.09-1.23) to H1 (median, 0.19 EU/mL; interquartile interval, 0.07-0.75; P = .03) and remained stable between H1 and H4 (median, 0.12 EU/mL; interquartile interval, 0.09-0.30; P = .4) . IL-6 levels fell between H0 and H4 (P = .01) and between H1 and H4 (P = .03) . IL-8 was higher at H0 than at H1 (P = .04) and at H4 (P = .01) . These results suggest that endotoxemia is not increased by antibiotherapy of severe gram-negative bacteremia. Gastroenterology, 1998 Jul, 115(1), 110 - 5 Vegetative infection of transjugular intrahepatic portosystemic shunts; Sanyal AJ et al.; BACKGROUND & AIMS: The occurrence of and the clinical picture of infection of transjugular intrahepatic portosystemic shunts (TIPS) has not been described previously . We describe the clinical features, associated pathogens, results of treatment of a previously unreported complication of TIPS, and primary infection of TIPS occurring after formation of the neointima . METHODS: Patients with TIPS and fever were evaluated to exclude other sources of infection . The diagnosis was based on the occurrence of fever with positive blood cultures and either a thrombus or vegetations on the stent or persistent bacteremia in a patient with a TIPS and no other detectable source of infection despite an extensive search . RESULTS: Eight patients met diagnostic criteria . Two of 8 cases occurred within 10 days of TIPS manipulation despite antibiotic administration before the procedure . The clinical features included fever (8 patients), tender hepatomegaly (5 of 8), hypoxemia (2 of 8), septic pulmonary emboli (1 of 8), septic shock (2 of 8), neutrophilia (5 of 8), and subsequent development of necrotizing fasciitis (1 of 8) . Blood cultures were positive in all cases . The organisms included oral and enteric aerobic gram-negative bacteria in 7 of 8 patients and Candida in 1 patient . All 8 responded to administration of antibiotics . Two patients died of myocardial infarction and alcoholic hepatitis, respectively . CONCLUSIONS: Infective endotipsitis is an uncommon complication of TIPS . Recognition of its clinical features will facilitate diagnosis . Most patients responded to antibiotic therapy. Appl Environ Microbiol, 1998 Jul, 64(7), 2710 - 5 Plasposons: modular self-cloning minitransposon derivatives for rapid genetic analysis of gram-negative bacterial genomes; Dennis JJ et al.; A series of modular mini-transposon derivatives which permit the rapid cloning and mapping of the DNA flanking the minitransposon's site of insertion has been developed . The basic plasposon, named TnMod, consists of the Tn5 inverted repeats, a conditional origin of replication, rare restriction endonuclease multiple cloning sites, and exchangeable antibiotic resistance cassettes . The broad host range and low target DNA sequence specificity of the Tn5 transposase, in combination with the flexibility afforded by the modular arrangement of TnMod, result in a versatile tool for the mapping of insertional mutations and the rapid recovery of clones from gram-negative bacteria. Res Commun Mol Pathol Pharmacol, 1998 Apr, 100(1), 3 - 14 In vitro effect of bacterial lipopolysaccharide on the cytotoxicity of human natural killer cells; Miranda D et al.; Preincubation with a number of mediators of infection, such as Gram negative bacteria (S . typhi), bacterial lipopolysaccharide (LPS), tumor necrotic factor-alpha (TNF-alpha), and interleukin-2 (IL-2), significantly increases natural killer (NK) cell activity in samples of human peripheral blood mononuclear cells (PBMC), without changing the levels of either the phenotypic CD16/56 or stimulatory CD25 marker . We now report similar results after preincubation of highly purified NK cell preparations (CD16 + 56 > 95%; the rest corresponding to CD3+ T-cells) with either S . typhi, TNF-alpha or IL-2 . However, in similar experiments, LPS inhibits, in a dose-dependent manner (final conc . 2.5, 5.0 or 10.0 micrograms/mL), NK cell cytotoxicity against K-562 tumor cells . Preincubation of purified NK cells with LPS (25 micrograms/mL; 10 and 30 min) produced significant alterations in the tyrosine phosphorylation/dephosphorylation pattern of several intracellular proteins, including a significant increase (10 min) in the phosphorylation of the 120; 100; 72 and 59 kDa proteins, followed (30 min) by the essentially complete desphosphorylation of the p59 protein . Qualitatively similar results were obtained at lower LPS concentrations e.g., range 2.5 to 20 micrograms/mL . The absence of phosphoproteins in the 40-44 kDa range, known to be present after incubation of monocytes with LPS, raises the possibility that these "class" of proteins may be critical in explaining the LPS inhibitory effect on NK lytic function . Our finding may contribute to a better understanding of the mechanisms involved in the complex in vivo interaction between LPS, monocytes and NK cells. Commun Dis Public Health, 1998 Jun, 1(2), 129 - 31 Progress in the development of Helicobacter pylori strain typing methods; Owen RJ et al.; Helicobacter pylori is very different from other Gram negative bacteria that inhabit the human gastroduodenal tract . Its success in adapting to colonise and persist in the stomach is reflected in key features such as unique chemical structure and architecture of lipopolysaccharide, sheathed flagella, genomic diversity, and potent urease activity . Strain diversity within the species is well established and so the challenge is to exploit variations in these features for developing relevant epidemiological typing methods. Mol Microbiol, 1998 May, 28(4), 675 - 81 TonB-dependent iron acquisition: mechanisms of siderophore-mediated active transport; Moeck GS et al.; Cells growing in aerobic environments have developed intricate strategies to overcome the scarcity of iron, an essential nutrient . In gram-negative bacteria, high-affinity iron acquisition requires outer membrane-localized proteins that bind iron chelates at the cell surface and promote their uptake . Transport of bound chelates across the outer membrane depends upon TonB-ExbB-ExbD, a cytoplasmic membrane-localized complex that transduces energy from the proton motive force to high-affinity receptors in the outer membrane . Upon ligand binding to iron chelate receptors, conformational changes are induced, some of which are detected in the periplasm . These structural alterations signal the ligand-loaded status of the receptor and, therefore, the requirement for TonB-dependent energy transduction . Thus, TonB interacts preferentially and directly with ligand-loaded receptors . Such a mechanism ensures the productive use of cellular energy to drive active transport at the outer membrane. Vet Immunol Immunopathol, 1998 Apr 16, 62(3), 235 - 44 Flow cytometric measurement of neutrophil alkaline phosphatase before and during initiation of an induced Escherichia coli mastitis in cattle; van Werven T et al.; In 12 healthy cows, neutrophil alkaline phosphatase (NAP) activity was measured by flow cytometer before and during an experimentally induced Escherichia coli mastitis, to study the role and increase of NAP in Gram-negative bacterial infections . Percentage of neutrophils containing alkaline phosphatase and intensity of NAP activity were measured . Preinfection percentage of neutrophils with enzyme activity varied between 64.0% and 84.4% and the intensity of enzyme activity was low in all cows . After induction of infection, percentage of neutrophils with enzyme activity showed a significant decrease on day 1 followed by an significant increase on day 3 . NAP intensity increased significantly on the second and third day after infection . This increase of intensity was significantly, positively correlated with the severity of infection . From this study we may conclude that variation in susceptibility to E . coli mastitis could not be explained by preinfection NAP levels . The post-infection increase of NAP activity, that was found following an induced infection was more a result of increased enzyme intensity per neutrophil, then from an increase of percentage neutrophils with enzyme activity . Furthermore, a strong correlation was found between NAP intensity and severity of inflammation . There was evidence that the more severely diseased animals showed stronger NAP intensity increase. J Cataract Refract Surg, 1998 Jun, 24(6), 866 - 7 Delayed-onset Pseudomonas stutzeri endophthalmitis after uncomplicated cataract surgery; Jiraskova N et al.; An 88-year-old woman had uneventful extracapsular cataract extraction with posterior chamber intraocular lens (IOL) implantation in her right eye . Seven weeks later, an anterior vitrectomy with removal of the IOL was performed because of endophthalmitis resistant to topical and systemic amoxicillin, cephalosporin, aminoglycoside, and steroids . Microbiological examination of the vitreous biopsy, capsule, and anterior chamber fluid disclosed Pseudomonas stutzeri, gram-negative nonfermentative bacteria sensitive to tetracycline, ceftazidime, gentamicin, ofloxacin, and piperacillin . Pseudomonas stutzeri should be considered in the treatment of delayed-onset endophthalmitis. Microbiology, 1998 Jun, 144 ( Pt 6), 1641 - 7 Molecular analysis of the DNA gyrB gene from Myxococcus xanthus; Paitan Y et al.; DNA gyrase, an essential type II topoisomerase, mediates negative supercoiling of the bacterial chromosome, thereby affecting the processes of DNA replication, transcription, recombination and repair . The gyrB gene from the Gram-negative soil bacterium Myxococcus xanthus was sequenced . The sequence predicts a protein of 815 amino acid residues displaying significant homology to all known GyrB proteins . A 6-His-GyrB fusion protein was overexpressed in Escherichia coli and purified to near homogeneity using affinity chromatography on Ni-nitrilotriacetic acid-agarose and novobiocin-Sepharose columns . The fusion protein bound novobiocin and cross-reacted with anti-E . coli GyrB antibodies, indicating structural and functional similarities to the E . coli DNA GyrB . The gene was mapped to the region of the origin of replication (oriC) of M . xanthus. Curr Microbiol, 1998 Jul, 37(1), 44 - 51 Isolation and characterization of Helicobacter species from the stomach of the house musk shrew (Suncus murinus) with chronic gastritis; Goto K et al.; A Gram-negative, motile bacterium with bipolar sheathed flagella (one at each end) was isolated from the stomach of house musk shrews (Suncus murinus) with chronic gastritis . The isolates grew at 37 degrees C under microaerophilic conditions, but not under aerobic conditions; rapidly hydrolyzed urea; were catalase, oxidase, alkaline phosphatase, and arginine aminopeptidase positive; reduced nitrate to nitrite; and were resistant to cephalothin and nalidixic acid, but sensitive to tetracycline, erythromycin, and chloramphenicol . This bacterium was found on gastric epithelial cells by electron microscopy . In addition, a coccoid form of the bacteria was found in vacuoles formed in the epithelial cells of some of the house musk shrews tested . These results, including 16S rRNA gene sequence analysis, strongly suggested that this bacterium should be classified as a novel Helicobacter species . It is proposed that this bacterium should be called "Helicobacter suncus." Zentralbl Bakteriol, 1998 May, 287(4), 421 - 5 Susceptibility of the anaerobic gram-negative non-sporulating rod, Bilophila wadsworthia to beta-lactams, beta-lactamase inhibitors, meropenem, metronidazole, clindamycin and quinolones; Schumacher UK et al.; The susceptibility of eighty-seven strain of Bilophila wadsworthia to five beta-lactams, two beta-lactamase inhibitors, meropenem, metronidazole, clindamycin and two quinolones was determined . Tests were performed by the modified reference agar dilution technique using triphenyltetrazolium chloride for endpoint reading . The test strains showed a reduced susceptibility to the beta-lactams, penicillin G (MIC90 4 micrograms/ml), ampicillin (MIC90 32 micrograms/ml), piperacillin (MIC90 64 micrograms/ml), cephalothin (MIC90 2 micrograms/ml and cefotaxim (MIC90 4 micrograms/ml) . The activity of ampicillin was increased by addition of the beta-lactamase inhibitor, sulbactam (MIC90 2 micrograms/ml), as was the activity of piperacillin by the addition of tazobactam (MIC90 4 micrograms/ml) 90.8% of the strains were found to produce beta-lactamase by the nitrocefin tube method . All strains were shown to be highly susceptible to meropenem, metronidazole and clindamycin (MICs < or = 1 microgram/ml) . Sparfloxacin (MIC90 1 microgram/ml) and ciprofloxacin (MIC90 0.5 microgram/ml) were found to be active against most of the strains tested. Infect Immun, 1998 Jul, 66(7), 3326 - 36 Cloning and mutagenesis of a serotype-specific DNA region involved in encapsulation and virulence of Actinobacillus pleuropneumoniae serotype 5a: concomitant expression of serotype 5a and 1 capsular polysaccharides in recombinant A . pleuropneumoniae serotype 1; Ward CK et al.; A DNA region involved in Actinobacillus pleuropneumoniae serotype 5 capsular polysaccharide (CP) biosynthesis was identified and characterized by using a probe specific for the cpxD gene involved in CP export . The adjacent serotype 5-specific CP biosynthesis region was cloned from a 5.8-kb BamHI fragment and an 8.0-kb EcoRI fragment of strain J45 genomic DNA . DNA sequence analysis demonstrated that this region contained four complete open reading frames, cps5A, cps5B, cps5C, and cps5D . Cps5A, Cps5B, and Cps5C showed low homology with several bacterial glycosyltransferases involved in the biosynthesis of lipopolysaccharide or CP . However, Cps5D had high homology with KdsA proteins (3-deoxy-D-manno-2-octulosonic acid 8-phosphate synthetase) from other gram-negative bacteria . The G+C content of cps5ABC was substantially lower (28%) than that of cps5D and the rest of the A . pleuropneumoniae chromosome (42%) . A 2.1-kb deletion spanning the cloned cps5ABC open reading frames was constructed and transferred into the J45 chromosome by homologous recombination with a kanamycin resistance cassette to produce mutant J45-100 . Multiplex PCR confirmed the deletion in this region of J45-100 DNA . J45-100 did not produce intracellular or extracellular CP, indicating that cps5A, cps5B, and/or cps5C were involved in CP biosynthesis . However, biosynthesis of the Apx toxins, lipopolysaccharide, and membrane proteins was unaffected by the mutation . Besides lack of CP biosynthesis, and in contrast to J45, J45-100 grew faster, was sensitive to killing in precolostral calf serum, and was avirulent in pigs at an intratracheal challenge dose three times the 50% lethal dose (LD50) of strain J45 . At six times the J45 LD50, J45-100 caused mild to moderate lung lesions but not death . Electroporation of cps5ABC into A . pleuropneumoniae serotype 1 strain 4074 generated strain 4074(pJMLCPS5), which expressed both serotype 1 and serotype 5 CP . However, serotype 1 capsule expression was diminished in 4074(pJMLCPS5) in comparison to 4074 . The recombinant strain produced significantly less total CP (serotypes 1 and 5 CP combined) in log phase (P = 0.0012) but significantly more total CP in late stationary phase than 4074 (P < 0.0001) . In addition, strain 4074(pJMLCPS5) caused less mortality and bacteremia in pigs and mice following respiratory challenge than strain 4074, indicating that virulence was affected by diminished capsule production . These results emphasize the importance of CP in the serum resistance and virulence of A . pleuropneumoniae. Int J Immunopharmacol, 1997 Sep-Oct, 19(9-10), 547 - 50 Bacterial cell wall components as immunomodulators--I . Lipopeptides as adjuvants for parenteral and oral immunization; Bessler WG et al.; We investigated the immunostimulatory properties of synthetically prepared lipopeptides derived from the cell wall of Gram negative bacteria . These compounds constitute potent macrophage activators and polyclonal B-lymphocyte stimulators . They are also immunoadjuvants in parenteral or oral immunization . By coupling the lipopeptides to haptens or low molecular weight antigens which are not immunogenic per se, highly immunogenic conjugates can be prepared . Lipopeptide antigen conjugates as synthetic vaccines give protection by enhancing the antibody-mediated immune response, and they stimulate the cellular immune response in vivo by priming of cytotoxic T-cells. Ann Fr Anesth Reanim, 1996, 15(8), 1168 - 72 {Influence of arteriovenous hemofiltration on teicoplanin pharmacokinetics}; Choufane S et al.; OBJECTIVE: To assess the pharmacokinetics of a single dose of teicoplanin in critically ill patients treated with continuous arteriovenous haemofiltration (CAVH) . STUDY DESIGN: Prospective open clinical study . PATIENTS: Eleven patients with acute renal insufficiency and suspected of a Gram negative infection . METHOD: After injection of teicoplanin, 6 mg.kg-1 over 30 minutes the plasma and haemofiltrate concentrations were measured over 24 hours with high power liquid chromatography (HPLC) . RESULTS: In plasma, the mean half-life of the first phase was 0.6 +/- 0.2 hour and terminal half-life was 16.4 +/- 5 8 hours, total clearance 30.4 +/- 7.1 mL.h-1.kg-1, volume of distribution was 0.7 +/- 0.3 L.kg-1 and the mean resident time 19.2 +/- 7.4 hours . In the haemofiltrate, the amount of teicoplanin eliminated after 24 hours was less than 1% in seven patients, between 1.8 and 3.7% in three and reached 7% in one patient . CONCLUSION: During CAVH, the elimination of a single dose of teicoplanin in the haemofiltrate is low. Biotechnology (N Y), 1996 Feb, 14(2), 189 - 91 Restricting the dispersal of recombinant DNA: design of a contained biological catalyst; Munthal MT et al.; To restrict horizontal gene spread and, thus, create organisms whose behavior in the field is more predictable, we have combined a mini-Tn5 cloning system that allows stable insertion of foreign genes into the chromosomes of a variety of Gram-negative bacteria with a gene-containment circuit based on the universal lethal-function colicin E3 . Use of the system is exemplified by the construction of a micro-organism designed to degrade polychlorinated biphenyls, important environmental pollutants . The relevant genotype of the microorganism is subject to a stringent gene-containment mechanism that provides neither an advantage nor a disadvantage to the host cell for survival, but decreases frequencies of productive chromosomal transfer frequencies by at least four orders of magnitude. Diagn Microbiol Infect Dis, 1998 Jun, 31(2), 355 - 68 Piperacillin/tazobactam versus imipenem: a double-blind, randomized formulary feasibility study at a major teaching hospital; Marra F et al.; With the introduction of piperacillin/tazobactam to the North American market, hospitals have been faced with the task of making a decision regarding its formulary role . In view of its broad spectrum of activity, piperacillin/tazobactam could be considered as a formulary alternative to imipenem . To evaluate the formulary feasibility of substituting piperacillin/tazobactam for imipenem, a comparative assessment of these agents in the empiric treatment of serious bacterial infections was undertaken at this tertiary care hospital . This trial was conducted as a randomized, double-blind, single-center study . Consenting adult patients (>16 years of age) who were prescribed imipenem were randomized to receive either 4 g of i.v . piperacillin/tazobactam or imipenem 500 mg of i.v . Q6H with or without concurrent antibiotics . Doses were adjusted according to renal function . There were no restrictions regarding the use of nonstudy antibiotics before and during the study period . Patients with beta-lactam allergies or meningitis or who had received greater than 72 h of previous imipenem therapy were excluded . Patients were evaluated at the end of treatment, at discharge, and at 30 days postdischarge . Endpoints included both clinical and microbiologic efficacy as well as drug toxicity . Over the 433-day study period, 360 imipenem treatment courses were initiated . Of these, 150 treatment courses (75 piperacillin/tazobactam courses and 75 imipenem courses) met study criteria and were subsequently randomized . The distribution of prescriber services for enrolled patients was similar to that for all patients receiving imipenem during the study period (p = 0.15) . Also, there were no statistically significant differences in demographic parameters between enrolled and excluded patients . For those patients enrolled in the study, demographic characteristics, treatment course indication(s), and accompanying antibiotics were similar across treatment arms . The mean duration of study drug therapy was 7.7 days (SD, 6.2) for imipenem and 7.5 days (SD, 6.7)for piperacillin/tazobactam (p = 0.84) . In the majority of cases, treatment discontinuation occurred as a result of a favorable treatment course outcome, stepdown to a narrower spectrum parenteral agent, or stepdown to an oral agent and did not differ between study drugs (p = 0.73) . Clinical and microbiologic treatment course outcomes were also similar across treatment arms . Clinical outcome was deemed successful or improved for 68% of imipenem and 70% of the piperacillin/tazobactam treatment courses (p = 0.54) . Fifty-three percent of treatment courses were microbiologically confirmed . Of the 58 courses that were assessed for microbiological outcome, 93% demonstrated successful eradication of the causative pathogens . There was no difference between study drugs (96% imipenem; 90% piperacillin/tazobactam; p = 0.61) . The proportion of treatment courses with at least one adverse event was similar between the study drugs (p = 1.0) . Nausea and/or vomiting were/was observed more commonly in the imipenem arm (p = 0.03) . Discontinuation of therapy due to drug toxicity occurred in 16% of imipenem and 5% of piperacillin/tazobactam treatment courses (p = 0.06) . There was no statistically significant difference between the mean treatment course cost for imipenem ($762; range, $55-$3192) versus piperacillin/tazobactam ($696; range, $79-$2967; p = 0.59) . In summary, piperacillin/tazobactam seems to represent a suitable alternative to imipenem for several clinical indications including intraabdominal infections, pneumonia, febrile neutropenia, and skin/soft tissue infections in which the causative pathogens are susceptible . However, in view of the prevalence of multiresistant Gram-negative aerobic pathogens at this institution, we do not believe that imipenem can be removed from the drug formulary . In addition, at the currently studied dosing regimen, there seems to be no evidence of a direct cost advantage associated with J Biol Chem, 1998 Jun 19, 273(25), 15661 - 6 Evidence for a new type of outer membrane lipid in oral spirochete Treponema denticola . Functioning permeation barrier without lipopolysaccharides; Schultz CP et al.; A new class of outer membrane lipid (OML) was isolated from the oral spirochete Treponema denticola strain ATCC 33521 using a phenol/chloroform/light petroleum procedure normally applied for lipopolysaccharide extraction . In addition to chemical analysis, Fourier transform infrared (FTIR) spectroscopy was applied to compare the biophysical properties of OML with lipopolysaccharides (LPS) and lipoteichoic acids (LTA) . Isolated OML fractions represent 1.4% of the total dry cell weight, are about 4 kDa in size, and contain 6% amino sugars, 8% neutral sugars, 14% phosphate, 35% carbazol-positive compounds, and 11% fatty acids (containing iso- and anteiso-fatty acyl chains) . Rare for outer membrane lipids, OML contains no significant amount of 3-deoxy-D-manno-octulosonic acids, heptoses, and beta-hydroxy fatty acids . The fatty acyl chain composition, being similar to that of the cytoplasmic membrane, is quite heterogeneous with anteiso-pentadecanoic acid (12%), palmitic acid (51%), and iso-palmitic acid (19%) as the predominant fatty acids present . Findings of a glycerol-hexose unit and two glycerol-hexadecanoic acid fragments indicate a glycolipid membrane anchor typically found in LTA . There was also no evidence for the presence of a sphingosine-based lipid structure . The results of FTIR measurements strongly suggest that the reconstituted lipid forms normal bilayer structures (vesicles) expressing a high membrane state of order with a distinct phase transition as typical for isolated LPS . However, in contrast to LPS, OML of T . denticola has a lower Tm near 22 degreesC and a lower cooperativity of the phase transition . The results suggest a different kind of permeation barrier that is built up by this particular OML of T . denticola, which is quite different from LPS normally essential for Gram-negative bacteria. J Comp Physiol {B}, 1998 Apr, 168(3), 177 - 82 Characteristics of the febrile response in Pekin ducks; Maloney SK et al.; We measured body temperature in Pekin ducks for 22 h after intravenous injection of the lipopolysaccharide (LPS) of gram negative bacteria at doses of 0, 1, 10, and 100 micrograms.kg body mass (-1) . The ducks developed monophasic fevers showing increases in peak temperature reached and duration of fever with increases in dose of LPS . Body temperatures of unrestrained telemetered ducks without access to food and water were similar to those of saline-injected controls in the fever experiments, but were lower in the morning than when the same birds had access to food and water . This nocturnal hypothermia may have resulted from energy restriction imposed by lack of food and water . The dose of LPS required to elicit a fever of over 18 h duration (100 micrograms.kg-1) will elicit a biphasic fever of 5 h duration in rats . Pekin ducks did not exhibit biphasic fever even at the highest LPS dose administered, indicating that while fever is superficially similar in the two homeothermic classes, there may be differences in details of the mechanism . The similarities of the dose/response characteristics to that of mammals lends support to the theory that fever in vertebrates has a common phyletic origin. J Paediatr Child Health, 1998 Jun, 34(3), 296 - 8 Massive subdural haematoma: an unusual complication of septicaemia in preterm very low birthweight infants; Ng PC et al.; Non-traumatic massive subdural haematoma is a rare condition in newborn infants and is usually associated with hereditary coagulation disorders or congenital vascular malformation . Its occurrence in preterm very low birthweight infants secondary to systemic bacterial infection has not been reported . We describe two extremely preterm neonates who developed massive subdural haematoma as a result of gram-negative septicaemia and disseminated intravascular coagulation . Both infants suffered severe parenchymal cerebral injury and hydrocephalus . Clinicians should be aware of this unusual and catastrophic complication if a very low birthweight infant with severe sepsis and disseminated intravascular coagulation suddenly deteriorates despite successful treatment with antibiotics . Radiological imaging by cranial ultrasound or computed tomography scanning should be routinely considered in all such infants for the detection of intracranial bleeding. J Biol Chem, 1998 May 15, 273(20), 12457 - 65 Accumulation of a lipid A precursor lacking the 4'-phosphate following inactivation of the Escherichia coli lpxK gene; Garrett TA et al.; The lpxK gene has been proposed to encode the lipid A 4'-kinase in Escherichia coli (Garrett, T . A., Kadrmas, J . L., and Raetz, C . R . H . (1997) J . Biol . Chem . 272, 21855-21864) . In cell extracts, the kinase phosphorylates the 4'-position of a tetraacyldisaccharide 1-phosphate precursor (DS-1-P) of lipid A, but the enzyme has not yet been purified because of instability . lpxK is co-transcribed with an essential upstream gene, msbA, with strong homology to mammalian Mdr proteins and ABC transporters . msbA may be involved in the transport of newly made lipid A from the inner surface of the inner membrane to the outer membrane . Insertion of an Omega-chloramphenicol cassette into msbA also halts transcription of lpxK . We have now constructed a strain in which only the lpxK gene is inactivated by inserting a kanamycin cassette into the chromosomal copy of lpxK . This mutation is complemented at 30 degreesC by a hybrid plasmid with a temperature-sensitive origin of replication carrying lpxK+ . When this strain (designated TG1/pTAG1) is grown at 44 degreesC, the plasmid bearing the lpxK+ is lost, and the phenotype of an lpxK knock-out mutation is unmasked . The growth of TG1/pTAG1 was inhibited after several hours at 44 degreesC, consistent with lpxK being an essential gene . Furthermore, 4'-kinase activity in extracts made from these cells was barely detectable . In accordance with the proposed biosynthetic pathway for lipid A, DS-1-P (the 4'-kinase substrate) accumulated in TG1/pTAG1 cells grown at 44 degreesC . The DS-1-P from TG1/pTAG1 was isolated, and its structure was verified by 1H NMR spectroscopy . DS-1-P had not been isolated previously from bacterial cells . Its accumulation in TG1/pTAG1 provides additional support for the pathway of lipid A biosynthesis in E . coli . Homologs of lpxK are present in the genomes of other Gram-negative bacteria. J Neuroimmunol, 1998 May 15, 85(2), 131 - 6 No increase in blood-brain barrier permeability after intraperitoneal injection of endotoxin in the rat; Bickel U et al.; Reactions mediated by the brain are part of the response to intraperitoneal administration of endotoxin, a model of gram-negative bacterial infection . To test the hypothesis that a compromised blood-brain barrier (BBB) may contribute to these reactions, the integrity of the BBB was measured following lipopolysaccharide administration . Rats received intraperitoneal injections of 50 microg/kg or 2 mg/kg of endotoxin . Brain uptake of a macromolecular vascular marker, 3H-labelled rat serum albumin, and of a poorly permeable low molecular weight substance, {14C}sucrose, was then measured with the intravenous bolus injection method . Compared to controls, neither dose of endotoxin affected the BBB permeability for these tracers . This was true when brain uptake was measured 5 min or 2 h after lipopolysaccharide injection . It is concluded that intraperitoneal endotoxin even at a high dose does not acutely disrupt the BBB. Arq Gastroenterol, 1997 Oct-Dec, 34(4), 207 - 11 {Comparison between invasive tests for the diagnosis of Helicobacter pylori infections}; Morais M et al.; Helicobacter pylori is a Gram negative bacteria that colonizes gastric epithelial cells . It has been associated with several gastric disease including chronic gastritis and peptic ulcer . Helicobacter pylori infection diagnosis can be done with invasive and non-invasive methods . In invasive methods an endoscopic gastric mucosa biopsy specimen is used . In our study we compare the sensitivity, specificity, costs and applicability of four invasive diagnostic tests: culture, urease ultra-rapid test, histology (Giemsa and Hematoxilineosin stain) and fuchsin stained mucosal slides . Urease test was the easiest, fastest diagnostic test, with sensitivity of 86% and specificity of 100%, being also the cheapest test . We concluded that it should be the test of choice for Helicobacter pylori infection diagnosis. Ann N Y Acad Sci, 1998 May 1, 840, 787 - 802 Neurohormonal host defense in endotoxin shock; Berczi I; Lipopolysaccharide (LPS) of gram-negative bacteria is capable of activating the immune system of higher animals, which may lead to cytokine-induced lethal shock and death . LPS has little toxicity for the frog and fish, but it kills the horseshoe crab instantly by causing intravascular blood coagulation . The response to LPS evolved from simple reactions in lower animals into an intense reaction in mammals that involves a massive immune activation leading to a profound neuroendocrine and metabolic response . This is now known as the acute-phase response (APR) . During APR, LPS-binding proteins (LBP) are produced by the liver in rapidly increasing quantities under the influence of interleukin-6, glucocorticoids, and catecholamines . After combination with LPS, LPB is capable of activating monocyte-macrophages and granulocytes via the CD14 surface receptor . Other receptors (CD18, 80-kDa receptor) allow for direct action by LPS of phagocytes, B and T lymphocytes, and other cells . Numerous other acute-phase proteins are produced in the liver, including C-reactive protein, complement components, fibrinogen, enzyme inhibitors, and anti-inflammatory proteins . Similar responses may be stimulated by subtoxic doses of LPS or by detoxified LPS, which manifest in endotoxin tolerance . Tolerant animals and man show increased resistance to LPS, to infections, and to various noxious insults . Infection and various forms of tissue injury are also capable of causing APR . There is much evidence to indicate that APR, which manifests in febrile illness, is an efficient host defense reaction . It is an emergency response in cases where specific immunity fails to protect the host . Therefore, the neuroimmunoregulatory network converts the immune system to a less specific, but rapid and more efficient response, APR . The hypothesis is presented that intestinal LPS serves to amplify the APR in response to various insults, which contribute to host defense, regeneration, and healing. Blood, 1998 Jun 15, 91(12), 4770 - 5 The bactericidal/permeability-increasing protein (BPI) is present in specific granules of human eosinophils; Calafat J et al.; Eosinophils participate in the inflammatory response seen in allergy and parasitic infestation, but a role in host defense against bacterial infection is not settled . The bactericidal/permeability-increasing protein (BPI) has been demonstrated in neutrophils and it exerts bacteriostatic and bactericidal effects against a wide variety of Gram-negative bacterial species . Using the Western blot technique, a 55-kD band, corresponding to BPI, was detected in lysates from both neutrophils and eosinophils . The localization of BPI in immature and mature eosinophils was investigated using immunoelectron microscopy . BPI was found in immature and mature specific granules of eosinophils and was detected in phagosomes as well, indicating release of the protein from the granules into the phagosomes . Using a specific enzyme-linked immunosorbent assay, eosinophils were shown to contain 179 ng of BPI/5 x 10(6) eosinophils compared with 710 ng BPI/5 x 10(6) neutrophils . The presence of BPI in eosinophils suggests a role for these cells in host defense against Gram-negative bacterial invasion or may suggest a role for BPI against parasitic infestation. J Biol Chem, 1998 Jun 12, 273(24), 14813 - 8 Phagocytosis of Escherichia coli by insect hemocytes requires both activation of the Ras/mitogen-activated protein kinase signal transduction pathway for attachment and beta3 integrin for internalization; Foukas LC et al.; Insect hemocytes in response to lipopolysacc