Microbiol Mol Biol Rev, 1998 Sep, 62(3), 547 - 85 Molecular regulation of beta-lactam biosynthesis in filamentous fungi; Brakhage AA; The most commonly used beta-lactam antibiotics for the therapy of infectious diseases are penicillin and cephalosporin . Penicillin is produced as an end product by some fungi, most notably by Aspergillus (Emericella) nidulans and Penicillium chrysogenum . Cephalosporins are synthesized by both bacteria and fungi, e.g., by the fungus Acremonium chrysogenum (Cephalosporium acremonium) . The biosynthetic pathways leading to both secondary metabolites start from the same three amino acid precursors and have the first two enzymatic reactions in common . Penicillin biosynthesis is catalyzed by three enzymes encoded by acvA (pcbAB), ipnA (pcbC), and aatA (penDE) . The genes are organized into a cluster . In A . chrysogenum, in addition to acvA and ipnA, a second cluster contains the genes encoding enzymes that catalyze the reactions of the later steps of the cephalosporin pathway (cefEF and cefG) . Within the last few years, several studies have indicated that the fungal beta-lactam biosynthesis genes are controlled by a complex regulatory network, e . g., by the ambient pH, carbon source, and amino acids . A comparison with the regulatory mechanisms (regulatory proteins and DNA elements) involved in the regulation of genes of primary metabolism in lower eukaryotes is thus of great interest . This has already led to the elucidation of new regulatory mechanisms . Furthermore, such investigations have contributed to the elucidation of signals leading to the production of beta-lactams and their physiological meaning for the producing fungi, and they can be expected to have a major impact on rational strain improvement programs . The knowledge of biosynthesis genes has already been used to produce new compounds. Acta Otolaryngol, 1998 Jul, 118(4), 557 - 62 Epidemiology and treatment of otitis media with effusion in children in the first year of primary school; Marchisio P et al.; In this multicentre study we evaluated the prevalence and risk factors of otitis media with effusion (OME) in Italian school-children and the effectiveness of medical treatment of chronic OME with a new cephalosporin, ceftibuten . During two winter periods, 3413 children, aged 5 to 7 years, were examined for the presence of OME by means of pneumotoscopy and a portable, hand-held tympanometer . The prevalence of asymptomatic OME was 14.2%, with no difference as regards sex, age, month of examination or geographic area . Younger children had significantly more bilateral than unilateral effusion . A recent episode of acute otitis media and previous tonsillectomy or adenoidectomy were associated with an increased risk of OME in multivariate logistic regression models . The presence of OME was unrelated to such factors as birthweight, prematurity, sibling or parental history of allergy, duration of daycare attendance, family history of ear infections . After 12 weeks, 26.6% of children with OME still had middle-ear fluid: 52 were randomized to ceftibuten (9 mg/kg q.d . for 14 days) and 59 to no treatment (nasal saline drops allowed) . Children treated with ceftibuten had a significantly better resolution of middle-ear effusion after 4 and 8 weeks . As mass screening programmes for OME in the year of school entry are questioned, a focus only on children with known risk factors seems advisable . Ceftibuten can be useful in reducing the duration of middle-ear effusion. J Antimicrob Chemother, 1998 Jul, 42(1), 95 - 8 Interaction of ceftriaxone with penicillin-binding proteins of Escherichia coli in the presence of human serum albumin; Fontana R et al.; The binding of ceftriaxone, a cephalosporin that exhibits high serum protein binding and prolonged serum half-life, to penicillin-binding proteins (PBPs) of Escherichia coli K12 in the presence of human serum albumin was compared with plasma concentrations of cefotaxime, a cephalosporin with low serum protein binding and a short serum half-life . Ceftriaxone concentrations equivalent to those maintained in plasma for 8 h after an intravenous infusion of 1 g saturated PBPs 2 and 3 . Cefotaxime saturated both PBPs at concentrations equivalent to those maintained for 2 h, and PBP 3 only at concentrations maintained for 2-8 h . These results indicate that high serum protein binding does not impair the ability of ceftriaxone to inhibit essential PBPs, and explain the high in-vivo efficacy of the drug. J Pharm Biomed Anal, 1998 Aug, 17(4-5), 871 - 5 ESR spectroscopy applied to the study of pharmaceuticals radiosterilization: cefoperazone; Basly JP et al.; As an alternative to heat and gas exposure sterilization, ionizing radiation is gaining interest as a sterilization process for medicinal products . Nevertheless, essentially for economic profits, an unauthorized and uncontrolled use of radiation process may be expected . In this context, it is necessary to find methods distinguishing between irradiated and unirradiated pharmaceuticals and, in the absence of suitable detection methods, our attention was focused on ESR spectrometry . In this paper, we examine the potential of ESR as an analytical tool in cefoperazone radiosterilization; this cephalosporin is a potential candidate for radiation treatment due to its thermosensitivity . While the ESR spectra of unirradiated sample present no intensity, a signal, dependent of the irradiation dose, is found exclusively in irradiated samples . The number of free radicals (2 x 10(17) radicals per g at 25 kGy) was estimated by comparison of the second integral from radiosterilized samples and DPPH . From this, the G-value could be estimated to 0.3 . Limit of detection and limit of quantification are 0.5 kGy and 1 kGy, respectively . Aside from qualitative detection, ESR can be used for dose estimation . The dose-ESR response curves can be simulated by bi-exponential or power functions and the linear function can't be used for simulation even for low doses . Decay of radicals upon storage were simulated using bi-exponential function . The limit of detection of free radicals after irradiation at 25 kGy is 140 days. Antimicrob Agents Chemother, 1998 Jul, 42(7), 1718 - 21 Pharmacokinetic study of an oral cephalosporin, cefdinir, in hemodialysis patients; Hishida A et al.; The pharmacokinetics of cefdinir were investigated in six hemodialysis patients . For the present study, two tests were carried out, one with 4 h of hemodialysis and the other without hemodialysis . Cefdinir was given orally to each patient in a dose of 100 mg, and blood was collected serially for 48 h after dosing in the test without dialysis and for 72 h in the test with dialysis . In the test without dialysis, the maximum plasma concentration (Cmax) was 2.36 +/- 0.53 micrograms/ml (mean +/- standard deviation) and the time to Cmax was 9.00 +/- 2.45 h . The terminal elimination half-life (t1/2) and area under the concentration-time curve (AUC) were 16.95 +/- 1.20 h and 69.05 +/- 14.84 micrograms.h/ml, respectively . In the test with dialysis, t1/2 during hemodialysis decreased approximately to one-sixth of that obtained in the test without dialysis, although t1/2 in the latter elimination phase did not differ from that in the nondialysis test . AUC was reduced to 43% of that in the test without dialysis . The fractional removal of cefdinir by hemodialysis was 61% . These findings indicate that clearance of cefdinir is prolonged in patients with renal failure, and cefdinir is well removed by introduction of hemodialysis, although t1/2 (during hemodialysis) and AUC were two and eight times higher than the data previously reported for healthy volunteers, respectively . The pharmacokinetic data suggest that 100 mg of oral cefdinir once a day would result in a sufficient concentration in plasma in hemodialysis patients, but this remains to be confirmed by multiple-dose studies. Semin Neurol, 1998, 18(2), 185 - 96 Pearls and pitfalls in the diagnosis and management of central nervous system infectious diseases; Roos KL; Laboratory techniques for the diagnosis of central nervous system (CNS) infections are rapidly improving but at present have limitations that necessitate our guarded enthusiasm . Enteroviruses are the most common infectious agents of viral meningitis for which an etiology can be determined, and it is anticipated that the use of the reverse transcriptase polymerase chain reaction (RT-PCR) technique should significantly improve the identification of the etiologic agent of aseptic meningitis . The combination of the polymerase chain reaction technique with laboratory methods for the determination of intrathecal antibody production to herpes simplex virus and varicella-zoster virus have improved the rapidity with which these viral infections can be diagnosed . The pearls and pitfalls of the use of these laboratory techniques in the diagnosis of viral meningitis, recurrent meningitis, and focal encephalitis are included . Recommendations for the empiric therapy of bacterial meningitis in children and adults have changed because of the emergence of penicillin and cephalosporin-resistant pneumococcal organisms . The currently recommended antibiotics and their dosages are included . The evidence for the efficacy of dexamethasone therapy in bacterial meningitis is provided . Meningitis due to Mycobacterium tuberculosis is increasingly recognized, and the initiation of empiric antituberculous chemotherapy should not await the results of CSF cultures . Toxoplasma encephalitis and primary CNS lymphoma are the most common cause of mass lesions in patients with HIV, and the diagnostic techniques to distinguish between these two infections is reviewed . A short discussion of the best test for the diagnosis of neurosyphilis is provided. Folia Microbiol (Praha), 1998, 43(1), 68 - 70 In vitro susceptibility of 90 penicillin-susceptible and -resistant pneumococci to penicillin G, amoxicillin, amoxicillin/clavulanate, cefaclor, cefuroxime, cefpodoxime, cefixime and imipenem; Hupkova H et al.; In vitro susceptibility of eight antibiotics was compared using three groups of pneumococci and agar dilution method comprising 30 penicillin-susceptible, 30 intermediately penicillin-resistant, and 30 highly penicillin-resistant pneumococci . Decreased sensitivity to all beta-lactam agents of intermediately penicillin-resistant and highly penicillin-resistant pneumococci is shown . MIC50 and MIC90 was lower with amoxicillin with and without clavulanate by one dilution than with penicillin . Cephalosporin MIC90s were all significantly higher for intermediately resistant and fully resistant strains . Only imipenem was more active than penicillin with MIC90 of susceptible pneumococci 0.015 mg/L, intermediately resistant pneumococci 0.25 mg/L, resistant pneumococci 1 mg/L. Antimicrob Agents Chemother, 1998 Apr, 42(4), 921 - 6 Overexpression, purification, and characterization of the cloned metallo-beta-lactamase L1 from Stenotrophomonas maltophilia; Crowder MW et al.; The metallo-beta-lactamase L1 from Stenotrophomonas maltophilia was cloned, overexpressed, and characterized by spectrometric and biochemical techniques . Results of metal analyses were consistent with the cloned enzyme having 2 mol of tightly bound Zn(II) per monomer . Gel filtration chromatography demonstrated that the cloned enzyme exists as a tightly held tetramer with a molecular mass of ca . 115 kDa, and matrix-assisted laser desorption ionization and time-of-flight mass spectrometry indicated a monomeric molecular mass of 28.8 kDa . Steady-state kinetic studies with a number of diverse penicillin and cephalosporin antibiotics demonstrated that L1 effectively hydrolyzes all tested compounds, with k(cat)/Km values ranging between 0.002 and 5.5 microM(-1) s(-1) . These characteristics of the recombinant enzyme are contrasted to those previously reported for metallo-beta-lactamases isolated directly from S . maltophilia. Bioconjug Chem, 1998 Mar-Apr, 9(2), 255 - 9 Development and activities of a new melphalan prodrug designed for tumor-selective activation; Kerr DE et al.; The synthesis of C-Mel, a cephalosporin carbamate derivative of the clinically used alkylating agent melphalan, is described . C-Mel was designed as an anticancer nitrogen mustard prodrug that releases melphalan upon tumor-specific activation by targeted beta-lactamase (bL) . The Km and kcat values for bL hydrolysis of C-Mel were 218 microM and 980 s(-1), respectively . In vitro cytotoxicity assays with 3677 human melanoma cells demonstrated that C-Mel was 40-fold less toxic than melphalan and was activated in an immunologically specific manner by L49-sFv-bL, a recombinant fusion protein that binds to the melanotransferrin antigen on melanomas and on some carcinomas . L49-sFv-bL in combination with C-Mel led to regressions and cures of established subcutaneous 3677 tumors in nude mice . The effects were significantly greater than those of melphalan, which did not result in any long-term regressions in this tumor model . The therapeutic effects were comparable to those obtained in mice treated with the previously described L49-sFv-bL/7-(4-carboxybutanamido)-cephalosporin mustard (CCM) combination . However, C-Mel may be more attractive than CCM for clinical development since the released drug is clinically approved. Chest, 1998 Mar, 113(3 Suppl), 183S - 187S Community-acquired pneumonia guidelines--an international comparison: a view from Europe; Woodhead M; Following an outline that details the pathogens causing community-acquired pneumonia (CAP) identified in studies from Europe, this article reviews the guidelines for the management of CAP in four European countries--France, Italy, Spain, and the United Kingdom . The method behind the development of each document is described, followed by a comparison of the scope of each document . All four documents provide guidelines for the management of two groups of patients--the severely ill and the nonseverely ill patient . A penicillin or macrolide feature for the nonseverely ill and the combination of a third-generation cephalosporin plus a macrolide for the severely ill patient are described in all four guidelines . Despite their different origins and methods, these four guidelines have more similarities than differences--the latter serving to emphasize some of the areas that require further research in this important condition . An important area for research is the impact that these guidelines have on practice and especially on clinical outcomes. Toxicol Pathol, 1998 Jan-Feb, 26(1), 52 - 7 The role of transport in chemical nephrotoxicity; Berndt WO; Various physiologic factors play a role in determining the extent of chemical-induced nephrotoxicity . One such factor relates to the transport systems that exist in the kidney . Several examples can be given of organic substances that are nephrotoxic only after being transported into renal tubular cells . Some of the cephalosporin antibiotics have been shown to produce proximal tubular necrosis after transport into those cells . Blockade of transport by competitors eliminates or reduces the nephrotoxic response . Citrinin, a secondary product of fungal metabolism, also produces proximal tubular necrosis, but only after transport into proximal tubular cells . Both the cephalosporins and citrinin utilize the organic anion transporter for entry into the cells, a transporter present in adult animals of all species and probably important physiologically for moving metabolic substrates into cells . Various glutathione conjugates (e.g., S-(1,2-dichlorovinyl) glutathione {DCVG}) also are transported into proximal tubular cells with a resulting nephrotoxicity . DCVG utilizes the sodium-dependent transport process that moves glutathione into proximal tubular cells, a process that is inhibited by probenecid . Finally, certain heavy metals also are transported into renal tubular cells . For example, mercuric ion enters proximal cells both from the luminal and peritubular sides and sulfhydryl compounds modify the transport . Movement of mercury from the peritubular side of the cell may be modified by certain organic anions . The characteristics of these mechanisms are less well understood than the mechanisms for the organic compounds. Otolaryngol Pol, 1997, 51(4), 390 - 5 {The evaluation of ceftibuten (Cedax) effectiveness in the prevention of perioperative infections}; Szmeja Z et al.; Cedax is the antibiotic drug of the third generation cephalosporin type . In the Department of Otolaryngology of the University Medical School in Poznan tests were carried out on the effectiveness of this drug in the prevention of perioperative infections (tonsillectomy, adenotomy, septoplastics, nasal polypectomy, mucotomy) . The experiment comprised 50 patients who were administered Cedax once a day of the period of five consecutive days, beginning on the day of the surgery . Control group compare 50 patients who did not receive the antibiotic cover . For the comparison of both groups the following symptoms were taken into account: general condition of the patient, body temperature in the first few days after the surgery, the healing of the operative wound (the condition of mucosa, healing "per primam" or "per secundam"), the presence and type of nasal discharge . A high degree of efficiency of ceftibuten has observed. Clin Chem, 1998 Feb, 44(2), 408 - 14 Clinical outcome and economic impact of aminoglycoside peak concentrations in febrile immunocompromised patients with hematologic malignancies; Binder L et al.; The aim of this study was to investigate the clinical and economic significance of aminoglycoside peak concentrations in febrile neutropenic patients with hematologic malignancies . Sixty-one patients were treated according to protocol II of the Paul-Ehrlich-Gesellschaft: initial application of gentamicin or tobramycin in combination with a cephalosporin or ureidopenicillin and, after 3 days, a potential change of antibiosis to be decided in case of nonresponse . At the same time, samples were collected by an independent controller . We found a significant dependence of clinical outcome on aminoglycoside peak concentrations (P = 0.004) . Twelve of 17 patients with peak concentrations > 4.8 mg/L, but only 13 of 44 patients with concentrations < or = 4.8 mg/L, responded to initial therapy . Average infection-related costs per patient with peak values > 4.8 mg/L were US$1429, $1790, and $1701 for nursing, diagnostics, and therapeutics, respectively (total $4920) . Expenses for patients with peak concentrations < or = 4.8 mg/L were approximately 1.8-fold higher (average total $8718) . If all 61 patients had achieved peaks > 4.8 mg/L, the potential savings would have totalled $167,112 . We conclude that neutropenic patients form a target group for successful pharmacokinetic intervention and cost saving. J Pediatr, 1998 Jan, 132(1), 137 - 43 Diagnosis of penicillin, amoxicillin, and cephalosporin allergy: reliability of examination assessed by skin testing and oral challenge; Pichichero ME et al.; The specificity of pediatrician-diagnosed allergy reactions to penicillin, amoxicillin, and oral cephalosporins, which was based on contemporaneous examination of the patient, was evaluated by an elective skin testing program . Children and adolescents (n = 247) experiencing an adverse reaction to penicillin, amoxicillin, and/or an oral cephalosporin sufficient to lead to the recommendation to avoid further use were enrolled . Skin testing with penicillin G, commercial benzylpenicilloyl phosphate, penicillin minor determinate mixture, ampicillin, cefazolin, cefuroxime, and ceftriaxone was performed according to the suspected drug allergy followed by an oral challenge, repeat testing, and prospective follow-up if no reactions were observed . Overall, 84 (34.0%) of 247 patients had an IgE-type reaction on skin testing or oral challenge . Twenty-seven (32%) of 85 suspected penicillin reactions, 53 (34%) of 156 suspected amoxicillin reactions, and 13 (50%) of 26 suspected cephalosporin reactions were shown to be IgE mediated . Positive skin tests were observed in 20 patients with non-IgE-type clinical adverse reactions, including 15 patients with only a pruritic polymorphous rash . No reactions to oral challenge were severe after negative skin testing . One hundred sixty-three patients received multiple treatment courses with beta-lactam antibiotics after a negative skin testing procedure and three (1.8%) had adverse IgE reactions, all of which were mild . Physician-diagnosed allergic reactions to beta-lactam antibiotics based on patient examination at the time of the reaction is more accurate than patient history alone but still overestimates the rate of possible true allergy in 66% of patients . Elective penicillin, amoxicillin, and cephalosporin skin testing and oral challenge protocols are necessary to identify patients not at risk. Pharmacotherapy, 1998 Jan-Feb, 18(1), 175 - 83 Pharmacoeconomic analysis of ampicillin-sulbactam versus cefoxitin in the treatment of intraabdominal infections; Messick CR et al.; We conducted a retrospective pharmacoeconomic analysis of a prospective, multicenter, double-blind, randomized, controlled trial comparing the beta-lactamase inhibitor combination ampicillin-sulbactam (96 patients) and the cephalosporin cefoxitin (101) in the treatment of intraabdominal infections . An institutional perspective was adopted for the analysis . The primary outcomes of interest were cure and failure rates, development of new infection, and antibiotic-related adverse events . Epidemiologic data pertaining to outcomes was retrieved primarily from the trial, although results of other published studies were taken into consideration through extensive sensitivity analyses . Data pertaining to potential resource use and economic impact were retrieved mainly from the University Health Consortium and hospital-specific sources . When considering only costs associated with drug acquisition through cost-minimization analysis, a potential savings of $37.24/patient may be realized with ampicillin-sulbactam relative to cefoxitin based on an average 7-day regimen . Outcome data collected for the entire hospitalization during the trial revealed an approximately 9% greater frequency of failure with cefoxitin relative to ampicillin-sulbactam . When considering all outcomes of interest in the initial base-case analysis, a potential cost savings of approximately $890/patient may be realized with ampicillin-sulbactam relative to cefoxitin . In assessing the impact of the significant variability in probability and cost estimates, Monte Carlo analysis revealed a savings of $425/patient for ampicillin-sulbactam over cefoxitin (95% CI -$618 to $1516 {corrected}) . Given the model assumptions, our analysis suggests a 78% certainty level that savings will be experienced when ampicillin-sulbactam is chosen over cefoxitin. Chem Biol, 1995 Apr, 2(4), 223 - 7 Synthesis and beta-lactamase-mediated activation of a cephalosporin-taxol prodrug; Rodrigues ML et al.; BACKGROUND: Enzyme-activatable prodrugs in conjunction with antibody-enzyme fusion proteins may enhance the anti-tumor efficacy of antibodies and reduce the toxic side effects of conventional chemotherapeutics . Cephalosporins have proven to be highly versatile triggers for the enzymatic activation of such prodrugs . RESULTS: A cephem prodrug of taxol (PROTAX) was synthesized by substituting the C-3' position of cephalothin with 2'-(gamma-aminobutyryl) taxol . Hydrolysis of PROTAX by beta-lactamase rapidly released 2'-(gamma-aminobutyryl) taxol (kcat/K(M) = (1.4 +/- 0.1) x 10(5) s-1 M-1), which yielded taxol following intramolecular displacement . PROTAX is inactive in a microtubule assembly assay in vitro but has similar activity to taxol following prolonged activation with beta-lactamase . PROTAX is approximately 10-fold less toxic than taxol against SK-BR-3 breast tumor cells in vitro but has activity approaching that of taxol following prolonged activation with a fusion protein comprising beta-lactamase fused to a tumor-targeting antibody fragment . CONCLUSIONS: Tubulin polymerization activity is abolished and cytotoxicity is reduced in the PROTAX prodrug compared to taxol . Activation of PROTAX by beta-lactamase followed by self-immolation restores the activity of PROTAX to that of free taxol. J Pharm Sci, 1998 Jan, 87(1), 53 - 8 A kinetic oxymoron: concentration-dependent first-order rate constants for hydrolysis of ceftazidime; Fubara JO et al.; The influence of pH, temperature, and buffers on the hydrolysis of 10(-4) M ceftazidime was previously reported . The pH-rate profiles showed that maximum stability occurred in the pH-independent region from 4.5 to 6.5 . In the present study, hydrolysis rates of 0.031, 0.14, 0.25, and 0.35 M ceftazidime were measured at 30 and 65 degrees C, pH 5.5-6.2 . The data were consistent with beta-lactam hydrolysis and the rapid release of pyridine . The sum of the time-dependent concentrations of ceftazidime and pyridine provided mass balance . Simultaneous nonlinear regression for ceftazidime loss and pyridine formation provided similar rate constants (k) to those determined from first-order plots of ceftazidime loss . Although the loss of ceftazidime was first-order for each initial concentration, the k values increased as the initial concentrations increased . Plots of k versus initial concentration were linear with intercepts similar to the k values for 10(-4) M solutions, thus implying that ceftazidime catalyzed its own degradation . At the pH of these studies ceftazidime exists as a base . The ceftazidime catalytic constant, calculated from the slope of the plot, was similar to that found for the general-base catalyst, HPO4(2-) . Therefore, it is feasible that ceftazidime also behaved as a intermolecular general-base catalyst . However, first-order plots exhibited excellent linearity even though the catalyst (ceftazidime) was consumed . This would require that the catalytic moieties on ceftazidime remained relatively constant throughout its hydrolysis . This hypothesis was shown to be consistent with literature reports which indicate that the general-base catalytic groups can remain relatively constant during cephalosporin hydrolysis. J Ind Microbiol Biotechnol, 1997 Nov-Dec, 19(5-6), 334 - 43 Evolving enzyme technology for pharmaceutical applications: case studies; Yeh WK; The case studies focus on two types of enzyme applications for pharmaceutical development . Demethylmacrocin O-methyltransferase, macrocin O-methyltransferase (both putatively rate-limiting) and tylosin reductase were purified from Streptomyces fradiae, characterized and the genes manipulated for increasing tylosin biosynthesis in S . fradiae . The rate-limiting enzyme, deacetoxycephalosporin C (DAOC) synthase/hydroxylase (expandase/ hydroxylase), was purified from Cephalosporium acremonium, its gene over-expressed, and cephalosporin C biosynthesis improved in C . acremonium . Also, heterologous expression of penicillin N epimerase and DAOC synthase (expandase) genes of Streptomyces clavuligerus in Penicillium chrysogenum permitted DAOC production in the fungal strain . Second, serine hydroxymethyltransferase of Escherichia coli and phthalyl amidase of Xanthobacter agilis were employed in chemo-enzymatic synthesis of carbacephem . Similarly, echinocandin B deacylase of Actinoplanes utahensis was used in the second-type synthesis of the ECB antifungal agent. BMJ, 1997 Dec 20-27, 315(7123), 1645 - 9 Risk factors for winter outbreak of acute diarrhoea in France: case-control study; Letrilliart L et al.; OBJECTIVES: To assess the potential role of consumption of shellfish (particularly raw oysters) and tap water in the winter epidemic of acute diarrhoea in France . DESIGN: Population based, case-control study during the 1995-6 winter epidemic of acute diarrhoea in France . SETTING: A national network comprising 1% of general practitioners in France . SUBJECTS: 568 pairs of cases and controls consulting in general practice and interviewed by 209 doctors from 26 December 1995 to 31 January 1996 . Cases and controls were matched for age, doctor, and time of consultation . MAIN OUTCOME MEASURES: Adjusted relative risk of diarrhoea estimated from conditional logistic regression . RESULTS: The risk of acute diarrhoea was not increased in people who had recently eaten raw oysters (odds ratio 1.1; 95% confidence interval 0.9% to 1.4%) or other shellfish such as clams, cockles, and mussels, or in those people who usually consumed tap water rather than bottled water (0.8; 0.6% to 1.1%) . The risk was, however, increased in people who had had recent contact wit ha person with diarrhoea either within the household (adjusted odds ratio 5.0) or in the workplace (3.1), and in people who lived with a child < or = 2 years of age (1.6) . Recent treatment with either oral penicillin or cephalosporin was also independently associated with acute diarrhoea in winter . CONCLUSIONS: The winter epidemic of acute diarrhoea in France is probably not caused by consumption of either shellfish or tap water . A viral aetiology, however, is suggested by the speed with which the acute diarrhoea is transmitted. J Orthop Trauma, 1998 Jan, 12(1), 1 - 7 Treatment of type II, IIIA, and IIIB open fractures of the tibial shaft: a prospective comparison of unreamed interlocking intramedullary nails and half-pin external fixators; Henley MB et al.; OBJECTIVE: To compare unreamed intramedullary nailing (IMN) with external fixation (EF) in patients with Type II, IIIA, and IIIB open fractures of the tibial shaft . DESIGN: An inception cohort of consecutive patients with Type II, IIIA, and IIIB tibial fractures incurred between January 1988 and March 1993 were systematically allocated into one of two treatment groups . Patients were treated and followed with a prospectively designed protocol . PATIENTS AND SETTING: All patients were skeletally mature and had incurred a fracture of the tibial diaphysis within twenty-four hours of presentation to the tertiary care hospital, a Level I Trauma Center . One hundred seventy-four fractures in 168 patients were stabilized with either IMN (104) or half-pin EF (70) . There were 132 men and thirty-six women, with an average age of thirty-three years (range, 14 to 77 years) . INTERVENTION: Except for the selection of the fixation device, open fracture care was similar in the two treatment groups . All patients underwent emergent irrigation and debridement with concomitant skeletal stabilization . Cephalosporin antibiotics were administered perioperatively for twenty-four to forty-eight hours . No wounds were closed primarily . Delayed primary closure, skin grafting, and/or myoplasty were performed between three and ten days after injury . MAIN OUTCOME MEASURES: The main outcome measures were final fracture alignment, presence of infection or inflammation, hardware failure, time to union, and the number of operative procedures . RESULTS: The IMN group had significantly fewer incidences of malalignment than did the EF group {8 vs . 31 percent; p = 0.00005; confidence interval (CI) = 0.18, 0.76} and had significantly fewer subsequent procedures (mean of 1.7 vs . mean of 2.7 per fracture; p = 0.001; CI = 0.45, 1.59) . IMN resulted in fewer infections/ inflammatory problems than did EF at the injury site (13 vs . 21 percent; p = 0.73; CI = -0.63, 0.45) and significantly fewer at surgical interfaces (i.e., pin sites, nail and interlocking screw insertion sites; 2 vs . 50 percent; p = 0.000; CI = 0.39, 0.60) . No significant difference was found in the healing rates for the two implant groups . The more severe Gustilo injury types had longer healing times regardless of the type of fixation . CONCLUSIONS: Results suggest that unreamed interlocking intramedullary nails are more efficacious than half-pin external fixators, in particular with regard to maintenance of limb alignment . However, the severity of soft tissue injury rather than the choice of implant appears to be the predominant factor influencing rapidity of bone healing and rate of injury site infection. Appl Microbiol Biotechnol, 1997 Nov, 48(5), 606 - 14 Expression of the cefG gene is limiting for cephalosporin biosynthesis in Acremonium chrysogenum; Gutierrez S et al.; The conversion of deacetylcephalosporin C to cephalosporin C is inefficient in most Acremonium chrysogenum strains . The cefG gene, which encodes deacetylcephalosporin C acetyltransferase, is expressed very poorly in A . chrysogenum as compared to other genes of the cephalosporin pathway . Introduction of additional copies of the cefG gene with its native promoter (in two different constructions with upstream regions of 1056 bp and 538 bp respectively) did not produce a significant increase of the steady-state level of the cefG transcript . Expression of the cefG gene from the promoters of (i) the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of Aspergillus nidulans, (ii) the glucoamylase (gla) gene of Aspergillus niger, (iii) the glutamate dehydrogenase (gdh) and (iv) the isopenicillin N synthase (pcbC) genes of Penicillium chrysogenum, led to very high steady-state levels of cefG transcript and to increased deacetylcephalosporin-C acetyltransferase protein concentration (as shown by immunoblotting) and enzyme activity in the transformants . Southern analysis showed that integration of the new constructions occurred at sites different from that of the endogenous cefG gene . Cephalosporin production was increased two- to threefold in A . chrysogenum C10 transformed with constructions in which the cefG gene was expressed from the gdh or gpd promoters as a result of a more efficient acetylation of deacetylcephalosporin C. J AOAC Int, 1997 Nov-Dec, 80(6), 1220 - 8 Induction and characterization of multianalyte antibodies against penicillins in egg yolk; de Leuw P et al.; Antibodies against penicillins were induced in eggs of laying hens after immunization with 6-aminopenicillanic acid (6-APA) coupled to key-hole limpet hemocyanin (KLH) . Development of the antibody titer was monitored by an indirect enzyme-linked immunosorbent assay (ELISA), with 6-APA coupled to ovalbumin as antigen for coating microtiter plates . Different characteristics (time course, affinity) of the immune reaction were observed by testing eggs of individual hens . Titer values varied between 150 and 2000 . Antibodies were isolated by polyethylene glycol precipitation and affinity chromatography, using a hapten sorbent with 6-APA as ligand . Glycine buffer, pH 3.0, was used to elute the immunoglobulins . Antibody specificity was determined in a competitive ELISA with 7 penicillins and the cephalosporin cephalexin as competitors . Cross reactivities for the penicillins were between 100 and 290% (6-APA = 100%) . Cephalexin cross reacted only marginally (3%). Enferm Infecc Microbiol Clin, 1997 Oct, 15 Suppl 3, 41 - 6 {Severe community-acquired pneumonia}; Insausti J et al.; There is no precise definition for severe community-acquired pneumonia (SEHP), but there are a number of factors which are associated with a greater severity, and which therefore recommended the admission of these patients in an intensive care unit (ICU) . In the present article, we mainly refer to SEHP in the immune competent population . SEHP makes up 8-10% of the total number of admissions of an ICU although this depends greatly on the type of unit concerned . The majority of patients admitted, do so because they need mechanical ventilation, because they present a shock situation, or because they develop a multi-organ failure in the course of the disease . The battery of usual tests recommended basically includes a chest x-ray, arterial gas, a count of red and white blood cells, biochemical profile, blood cultures, analysis and culture of the pleural liquid (if this is present), and respiratory samples . The therapeutic strategies tend to guarantee the simultaneous coverage of S . pneumoniae, H . influenzae, and the so-called atypical pathogens . Keeping in mind the considerable percentage of penicillin resistant pneumococcus existing in our country, in a general manner it is recommended to use a combination of a macrolide with a 3rd generation cephalosporin against this organism . They should be detected early, especially those situations in which there is respiratory failure and shock which shall require the use of mechanical ventilation and inotropics as well as an adequate monitoring. Appl Environ Microbiol, 1997 Dec, 63(12), 4807 - 11 Purification and characterization of a cephalosporin esterase from Rhodosporidium toruloides; Politino M et al.; A novel cephalosporin esterase (EC 3.1.1.41) from Rhodosporidium toruloides was purified to gel electrophoretic homogeneity . The enzyme is a glycoprotein with a molecular mass of 80 kDa . Upon deglycosylation, several forms of the enzyme were observed with a molecular mass range between 60 and 66 kDa . The isoelectric point of the enzyme is approximately 5.6, with the pH optimum for activity occurring at 6.0 . The optimal activity of the enzyme occurred at 25 degrees C, with the enzyme rapidly losing activity at temperatures above 25 degrees C . The enzyme deacetylated a variety of cephalosporin derivatives, including cephalosporin C; the Km for this substrate is 51.8 mM, and the Vmax is 7.9 mumol/min/mg . In addition to cephalosporins, the enzyme hydrolyzed short-chain p-nitrophenyl esters, with the activity decreasing with increasing ester chain length . The enzyme also has the ability to acetylate desacetyl cephalosporins in high yields under mild conditions in the presence of various acetyl donors . A comparison of the physical properties of the esterase with those of other well-characterized cephalosporin esterases indicates that the enzyme is unique in this class. Allergol Immunopathol (Madr), 1997 Sep-Oct, 25(5), 247 - 8 Fixed drug eruption from amoxycillin; Jimenez I et al.; We present a case of fixed drug eruption on the genital mucosa induced by amoxycillin . Topical provocation was carried out, applying amoxycilin (10% pet) on the glans penis . No reaction was observed . Oral challenge with amoxycillin was followed by pruritic erythema on the glans penis 6 hours after the intake of 125 mg . The study of cross-reactivity to other betalactams showed good tolerance of phenoxymethyl-penicillin, which shares an identical nuclear structure with amoxycillin . The patient also tolerated cephadroxil, a cephalosporin with a side chain identical to that of amoxycillin . On reviewing the literature we have only found three reports of fixed drug eruption fue to amoxycillin. Am J Obstet Gynecol, 1997 Oct, 177(4), 831 - 4 Randomized trial of single-dose versus multiple-dose cefotetan for the postpartum treatment of intrapartum chorioamnionitis; Chapman SJ et al.; OBJECTIVE: Our purpose was to determine whether a single postpartum dose of a cephalosporin would effectively treat women with intrapartum chorioamnionitis and decrease the length of hospitalization . STUDY DESIGN: After vaginal delivery consenting women who had received antibiotics for chorioamnionitis were assigned to postpartum treatment with either a single 2 gm intravenous dose of cefotetan or to cefotetan 2 gm given intravenously every 12 hours for a minimum of 48 hours . Chorioamnionitis was defined as an intrapartum temperature of > or = 100.4 degrees F and maternal or fetal tachycardia, maternal leukocytosis, or uterine tenderness . Patients were discharged when they had received their assigned dosage of cefotetan, were afebrile (temperature < 100.4 degrees F) and > or = 24 hours from delivery . RESULTS: We studied 109 women (55 single dose, 54 multiple dose) with chorioamnionitis . The two groups were similar with regard to demographic and intrapartum characteristics . The median (range) interval from delivery to discharge was 24 hours lower in the single-dose group (33 {16 to 190} vs 57 {36 to 190} hours, p = 0.0001) . The incidence of failed therapy was similar (single dose: 6/55, 11%, vs multiple dose: 2/54, 3.7%, p = 0.27) . CONCLUSIONS: A single postpartum dose of cefotetan appears to be effective treatment for intrapartum chorioamnionitis after a vaginal delivery and decreases the length of hospital stay. J Biol Chem, 1997 Nov 14, 272(46), 28833 - 6 Insertion mutagenesis as a tool in the modification of protein function . Extended substrate specificity conferred by pentapeptide insertions in the omega-loop of TEM-1 beta-lactamase; Hayes F et al.; The TEM-1 beta-lactamase enzyme efficiently hydrolyzes beta-lactam antibiotics such as ampicillin but cleaves third generation cephalosporin antibiotics poorly . Variant beta-lactamases that conferred elevated levels of resistance to the cephalosporin ceftazidime were identified in a set of beta-lactamase derivatives previously generated by pentapeptide scanning mutagenesis in which a variable 5-amino acid cassette was introduced randomly in the target protein . This mutagenesis procedure was also modified to allow the direct selection of variant beta-lactamases with pentapeptide insertions that conferred extended substrate specificities . All insertions associated with enhanced resistance to ceftazidime were targetted to the 19-amino acid Omega-loop region, which forms part of the catalytic pocket of the beta-lactamase enzyme . However, pentapeptide insertions in the C- and N-terminal halves of this region had different effects on the ability of the enzyme to hydrolyze ampicillin in vivo . Larger insertions that increased the length of the Omega-loop by up to 2-fold also retained catalytic activity toward ampicillin and/or ceftazidime in vivo . In accord with previous substitution mutation studies, these results emphasize the extreme flexibility of the Omega-loop with regards the primary structure requirements for ceftazidime hydrolysis by beta-lactamase . The potential of pentapeptide scanning mutagenesis in mimicking evolution events that result from the insertion and excision of transposons in nature is discussed. Bioconjug Chem, 1997 Sep-Oct, 8(5), 772 - 9 Synthesis of 17 beta-hydroxy esters of 4-estren-17 beta-ol-3-one and carbenicillin, ticarcillin, or functionalized oxacillin: potentially useful conjugates for beta-lactamase-based homogeneous immunoassays; Kohl M et al.; On the basis of the large range of kinetic constants of their substrates, beta-lactamases seem to be interesting enzymes for the development of homogeneous immunoassays . For this purpose, hapten-penicillin or -cephalosporin conjugates have to be prepared . The aim of this work is to couple the anabolizing steroid nandrolone to several penicillins characterized by extremely low K(m) and kcat values: ticarcillin, carbenicillin, and oxacillin . The easy decarboxylation of derivatives of phenylmalonic acid (carbenicillin) and thienylmalonic acid (ticarcillin) imposes the choice of very mild procedures which have been specifically adapted to each substance investigated . 4-Estren-17 beta-ol-3-one hemiphenylmalonate is conjugated to 6-aminopenicillanic acid after 1,1'-carbonyldiimidazole activation, while 4-estren-17 beta-ol-3-one hemi(3-thiophene)malonate is coupled to 6-aminopenicillanic acid after activation using methanesulfonyl chloride . Before conjugation of oxacillin, a carboxylated analogue of its side chain has been prepared . A procedure resorting to tert-butyl ester protection of the carboxyl group present on the isoxazole ring allows the binding of nandrolone to the remaining carboxyl followed, after specific deprotection, by the conjugation to 6-aminopenicillanic acid giving the oxacillin derivative . In this way, conjugates retaining immunological properties of nandrolone and high inhibiting power of beta-lactamases should be obtained. J Med Chem, 1997 Oct 10, 40(21), 3423 - 33 7-alkylidenecephalosporin esters as inhibitors of human leukocyte elastase; Buynak JD et al.; A series of 7-alkylidenecephalosporins and 7-vinylidenecephalosporins, as their benzhydryl esters, have been tested as inhibitors of both porcine pancreatic elastase and human leukocyte elastase . Selected 7-alkylidenecephalosporin esters are found to be potent inhibitors of HLE . One category of new inhibitors is the 7-(haloalkylidene)cephalosporins . In contrast to previously reported cephalosporin-based elastase inhibitors, these haloalkylidene cephems show optimum inhibitory activity as sulfides, rather than as sulfones . They are efficient and irreversible inhibitors . A second class of active compounds is represented by the benzhydryl ester 7-(cyanomethylidene)cephalosporin sulfone . In contrast to the activity of these new inhibitors, the benzhydryl ester of the mechanism-based beta-lactamase inhibitor, 7-{(2'-pyridyl)methylidene}-cephalosporin sulfone showed little inhibitory activity as an elastase inhibitor . 7-Vinylidenecephalosporins were also relatively poor inhibitors, although the terminally unsubstituted allene sulfide showed activity as an inhibitor of PPE . A modeling analysis suggests the 7-alkylidene substituents can be readily accommodated in the S1 pocket . A potential mechanism of inhibition is proposed. J Bacteriol, 1997 Oct, 179(19), 6112 - 21 AmpC and AmpH, proteins related to the class C beta-lactamases, bind penicillin and contribute to the normal morphology of Escherichia coli; Henderson TA et al.; Two proteins that bind penicillin were observed in Escherichia coli infected with lambda phages 141, 142, 650, and 651 from the Kohara genomic library . These phages carry chromosomal DNA fragments that do not contain any known penicillin binding protein (PBP) genes, indicating that unrecognized gene products were exhibiting penicillin binding activity . The genes encoding these proteins were subcloned, sequenced, and identified . One gene was ampC, which encodes a chromosomal class C beta-lactamase . The second gene was located at about 8.5 min on the E . coli genomic map and is a previously uncharacterized open reading frame, here named ampH, that encodes a protein closely related to the class C beta-lactamases . The predicted AmpH protein is similar in length to AmpC, but there are extensive alterations in the amino acid sequence between the SXXK and YXN motifs of the two proteins . AmpH bound strongly to penicillin G, cefoxitin, and cephalosporin C; was temperature sensitive; and disappeared from cells after overnight incubation in stationary phase . Although closely related to AmpC and other class C beta-lactamases, AmpH showed no beta-lactamase activity toward the substrate nitrocefin . Mutation of the ampC and/or ampH genes in E . coli lacking PBPs 1a and 5 produced morphologically aberrant cells, particularly in cell filaments induced by aztreonam . Thus, these two members of the beta-lactamase family exhibit characteristics similar to those of the classical PBPs, and their absence affects cell morphology . These traits suggest that AmpC and AmpH may play roles in the normal course of peptidoglycan synthesis, remodeling, or recycling. Clin Infect Dis, 1997 Sep, 25 Suppl 2, S272 - 4 beta-lactamase production by oral pigmented Prevotella species isolated from young children; Kononen E et al.; The frequency of beta-lactamase production by oral pigmented Prevotella species isolated from 23 healthy young children and the minimal inhibitory concentrations (MICs) for 186 available beta-lactamase-positive isolates were examined by using the chromogenic cephalosporin disk test (AB BIODISK, Solna, Sweden) and the Etest (AB BIODISK) and/or the agar dilution method of the National Committee for Clinical Laboratory Standards (Villanova, PA, USA), respectively . beta-Lactamase-positive Prevotella melaninogenica strains were isolated from all children, and more than two-thirds of the Prevotella denticola and Prevotella loescheii strains isolated from the children were beta-lactamase-positive . The beta-lactamase-producing Prevotella intermedia group consisted of Prevotella nigrescens and the P . intermedia/ P . nigrescens-like organism (PINLO); P . intermedia was not found . Only two P . nigrescens isolates but most of the PINLO isolates produced beta-lactamase . The MICs for beta-lactamase-producing strains varied between 0.38 and 64 micrograms/mL . beta-Lactamase production by oral pigmented Prevotella species colonizing young children is already frequent . The phenomenon should be taken into account in the treatment of pediatric anaerobic infections of oral origin. Arch Biochem Biophys, 1997 Sep 15, 345(2), 311 - 7 Protein carbonyl formation in blood plasma by cephalosporins; Jung Y et al.; Cephalosporin antibiotics caused the formation of carbonyl groups in the plasma proteins both in vivo and in vitro . After the administration of either moxalactam (3 g/day) or cefotaxime (2 g/day) to patients for 7 days, the carbonyl contents in the plasma proteins increased markedly as determined by the 2,4-dinitrophenylhydrazine (DNPH) method . The increase in protein carbonyl groups was also visualized by the conjugation of plasma proteins with fluorescein thiosemicarbazide (FTSC) and subsequent electrophoresis . When blood plasma was incubated with cephalosporins, most of the cephalosporins tested caused the carbonyl formation in plasma proteins to significant degrees in a concentration-dependent manner . Although a number of plasma proteins and other nonplasma proteins could be modified by cephalosporins in vitro, the plasma albumin was most markedly modified in vivo as well as in vitro . The protein carbonyl formation by cephalosporins was inhibited by ascorbic acid, reduced glutathione, and cysteine, but it was not affected by FeSO4, CuSO4, desferrioxamine, EDTA, catalase, superoxide dismutase, uric acid, alpha-tocopherol, and mannitol . Sodium borohydride, when applied to moxalactam-treated plasma proteins, markedly reduced the reactivities of the protein with FTSC or DNPH, indicating that the observed reactivities of the cephalosporin-treated proteins toward FTSC or DNPH are actually due to the protein carbonyl groups . These data suggest that cephalosporins can oxidatively modify proteins in blood plasma and other tissues and that the oxidative modification of proteins may be involved in the adverse reactions observed frequently following cephalosporin therapy. FEBS Lett, 1997 Sep 1, 414(1), 74 - 8 Penicillin biosynthesis: intermediates of biosynthesis of delta-L-alpha-aminoadipyl-L-cysteinyl-D-valine formed by ACV synthetase from Acremonium chrysogenum; Kallow W et al.; The tripeptide delta-L-alpha-aminoadipyl-L-cysteinyl-D-valine (LLD-ACV) is synthesised by the multifunctional enzyme ACV synthetase integrating four steps of the penicillin and cephalosporin biosynthetic pathway . Peptide synthesis follows the thiotemplate mechanism from intermediates bound as thioesters to the enzyme . The formation of delta-(L-alpha-aminoadipyl)-L-cysteinyl-thioester in the absence of L-valine was shown by isolation of the enzyme-substrate complex and cleavage of the covalently bound intermediate with performic acid . The dipeptide was recovered as cysteic acid or cysteic acid oxime and detected by HPLC and MALDI-TOF mass spectrometry . We conclude that the first peptide bond is formed between delta-carboxyl of L-aminoadipic acid and L-cysteine, followed by addition of the dipeptidyl intermediate to L-valine. Geriatrics, 1997 Aug, 52(8), 43 - 4, 47-50, 55 Meningitis in older patients: how to diagnose and treat a deadly infection; Miller LG et al.; Studies of bacterial meningitis have documented a peak of incidence among persons age 60 and older . The most common bacterial pathogens in these patients differ from those seen in children . Presentation of meningitis in older patients may be atypical; fever is not a consistent finding, and nonspecific symptoms such as confusion are often seen . Nuchal rigidity is not as sensitive nor as specific a sign as in younger patients . Definitive diagnosis relies on interpretation of CSF studies . Ampicillin plus a third-generation cephalosporin should be administered for community-acquired meningitis until Gram's stain and culture results return . Cases of S pneumoniae meningitis may require varying strategies, based upon the degree of penicillin resistance. Appl Microbiol Biotechnol, 1997 Jul, 48(1), 58 - 65 Efficient synthesis of the blood-coagulation inhibitor hirudin in the filamentous fungus Acremonium chrysogenum; Radzio R et al.; The isopenicillin-N-synthetase-encoding pcbC gene from the filamentous fungus Acremonium chrysogenum is differentially expressed in strains showing either a high or low cephalosporin C production . For a case study to demonstrate heterologous protein synthesis in A . chrysogenum, we have chosen a synthetic 195-bp gene encoding the thrombin inhibitor hirudin from the leech Hirudo medicinalis . The hirudin gene was fused with the 5' and 3' regions of the pcbC gene, resulting in four different expression vectors, which we named pHIR1 to pHIR4 . In order to achieve secretion of the heterologous polypeptide, two out of four vectors carry, in addition, secretion signal sequences of an alkaline protease gene originating either from Fusarium sp . or from A . chrysogenum . After DNA-mediated transformation of the two A . chrysogenum strains, transformants were further analysed on the transcriptional and translational level . Irrespective of the vector used for transformation, all transformants show a hirudin-gene-specific transcript in Northern hybridizations . In further analysis, hirudin synthesis was determined with a thrombin-inhibition assay, but was detectable only in those strains carrying expression plasmids with the secretion signals . In this case, hirudin was secreted into the culture medium . Transformants from strains with a high cephalosporin C production showed a three- to eightfold higher expression of the hirudin gene compared to low cephalosporin-C-producing strains . The amount of recombinant hirudin was quantified further by ELISA and Western blotting, using a monoclonal antibody directed against recombinant hirudin . Finally, the time course of hirudin gene expression was investigated in a selected transformant that has hirudin activities of 8.0 ATU/ml culture medium . Northern hybridization experiments revealed the highest hirudin transcript level after 2-5 days of cultivation, showing the strongest signal after 3 days . After 4-5 days, we detected the highest hirudin activity, as was confirmed by Western blotting . The level of heterologous hirudin synthesis in A . chrysogenum is discussed in relation to other eukaryotic expression systems. J Dermatol, 1997 Jul, 24(7), 485 - 7 Disseminated superficial porokeratosis in a patient with chronic liver disease; Park BS et al.; A 55-year-old male suffering from liver cirrhosis presented with diffuse annular hyperkeratotic papules of abrupt onset on the trunk and extremities . Histopathologic examination revealed cornoid lamella and eosinophilic spongiosis . He did not receive any medications other than cephalosporin for spontaneous bacterial peritonitis . A review of the literature revealed that three cases developed porokeratosis when their liver function declined and that, in one case, the porokeratosis disappeared spontaneously with liver transplantation . Although the precise mechanism is unclear, there is evidence demonstrating immunoincompetence in cirrhosis . Even though we did not perform immunologic studies or exclude the possibility of drug-induced porokeratosis in our case, it is conceivable that porokeratosis can be triggered by immunosuppression due to liver cirrhosis per se. Biochem Pharmacol, 1997 May 9, 53(9), 1223 - 8 Interaction of oligonucleotide-conjugates with the dipeptide transporter system in Caco-2 cells; Moore VA et al.; Oligonucleotide-based therapies represent novel strategies for manipulating the expression and function of target proteins and are undergoing clinical evaluation for the treatment of viral diseases and malignancies . However, poor biological stability and cellular delivery represent potential limitations to the therapeutic development of oligonucleotides . Conjugation of oligonucleotides to lipophilic groups can improve delivery to cells but the enhanced cellular binding may also facilitate nonspecific interactions . In this report, we show that phosphorothioate oligonucleotides conjugated to lipophilic groups, either tocopherol (Vitamin E) or 2-Di-O-hexadecyl-3-glycerol, can significantly inhibit the functioning of the dipeptide transporter system (DTS) in cultured Caco-2 intestinal cells . Because the DTS mediates the binding and absorption of nutrient peptides and important drugs, such as the cephalosporin and penicillin antibiotics, this finding has important implications in relation to the potential toxicity of lipophilic conjugates in vivo . It also suggests a potential drug interaction with lipophilic oligonucleotide-conjugates if they were to be delivered orally. J Pharm Pharmacol, 1997 May, 49(5), 516 - 9 Characteristics of cefdinir uptake by rabbit small intestinal brush-border membrane vesicles; Kitagawa S et al.; Aminocephalosporins with peptide-like structures have been shown to be absorbed by the intestinal peptide carrier . We investigated the transport mechanism of cefdinir, an oral monocarboxylic acid cephalosporin, using rabbit small intestinal brush-border membrane vesicles . Transport of cefdinir showed a slow and almost linear uptake rate for concentrations up to 30 mM with and without and inward H+ gradient . No overshoot phenomenon was observed in the presence of an inward H+ gradient . The uptake rate increased only slightly with decreasing extravesicular pH, and a protonophore had little effect on the uptake . Aminocephalosporins such as cephalexin only slightly inhibited cefdinir uptake even in the presence of an inward H+ gradient, and vice-versa . Monocarboxylic acids such as acetic acid and salicylic acid had little effect on cefdinir uptake . These findings suggest that in contrast with other oral cephalosporins cefdinir uptake through the brush-border membrane is slow and involves a mechanism similar to passive diffusion. J Pharm Sci, 1997 May, 86(5), 526 - 39 Isolation and structure elucidation of the major degradation products of cefaclor formed under aqueous acidic conditions; Baertschi SW et al.; The aqueous acidic degradation of the oral cephalosporin cefaclor was investigated . A number of degradation products were isolated and characterized . The degradation products can be loosely classified into three categories: thiazole derivatives, pyrazine derivatives, and simple hydrolysis or rearrangement products . Degradation pathways are proposed that involve (1) hydrolysis of the beta-lactam carbonyl with subsequent rearrangement, (2) ring contraction of the six-membered cephem nucleus to five-membered thiazole derivatives through an episulfonium ion intermediate, and (3) attack of the primary amine of the phenylglycyl side chain on the "masked aldehyde" at carbon-6 to form fluorescent substituted pyrazines. J Ind Microbiol Biotechnol, 1997 Apr, 18(4), 241 - 6 Partial purification, characterization and nitrogen regulation of the lysine epsilon-aminotransferase of Streptomyces clavuligerus; Romero J et al.; The L-lysine epsilon-aminotransferase (LAT) of Streptomyces clavuligerus was partially purified and characterized . The 51.3-kDa enzyme exhibited optimal activity at pH 7.0-7.5 and 30 degrees C . It catalyzed transfer of the terminal amino group of L-lysine or L-ornithine to alpha-ketoglutarate . Oxalacetate and pyruvate were also used as acceptors of the amino group but with very low efficiency . Increasing ammonium concentrations added to chemically-defined medium MM enhanced the formation of LAT and decreased production of cephalosporins by S . clavuligerus . In cultures grown in the absence of lysine, greater enhancement of LAT formation by ammonium and less repression of cephalosporin biosynthesis were observed . In the chemically-defined GSPG medium, ammonium ions decreased cephalosporin production without showing an effect on LAT formation. Biochim Biophys Acta, 1997 Mar 13, 1324(2), 296 - 308 Interaction of anionic cephalosporins with the intestinal and renal peptide transporters PEPT 1 and PEPT 2; Ganapathy ME et al.; The present study was undertaken to investigate the interaction of anionic cephalosporins (cefixime, ceftibuten, and cefdinir) with the renal peptide transporter (PEPT 2) and the intestinal peptide transporter (PEPT 1) using four different experimental model systems . In the first approach, the human colon carcinoma cell line Caco-2 which expresses PEPT 1 and the SHR rat kidney cell line SKPT which expresses PEPT 2 were used . The uptake of the dipeptide Gly-Sar mediated by PEPT 1 or PEPT 2 in these cells was inhibited significantly by the anionic cephalosporins, with the following order of potency: ceftibuten > cefixime > cefdinir . The inhibition was competitive in nature . Even though the order of potency was the same for PEPT 1 and PEPT 2, PEPT 1 exhibited much lesser sensitivity to inhibition than PEPT 2 . In the second approach, the cloned human PEPT 1 and PEPT 2 were functionally expressed in HeLa cells following which the cells were used to study the interaction of anionic cephalosporins with PEPT 1 and PEPT 2 . Again, Gly-Sar uptake mediated by the human PEPT 1 and PEPT 2 in HeLa cells was found to be inhibited by the anionic cephalosporins with the same order potency as in Caco-2 and SKPT cells . In the third approach, brush border membrane vesicles isolated from rat kidneys were employed . In this approach also it was found that PEPT 2-mediated Gly-Sar uptake was inhibited by cefixime and ceftibuten . In the fourth approach, the human PEPT 1 was expressed in Xenopus laevis oocytes and PEPT 1-mediated transport of ceftibuten was investigated directly by electrophysiological methods . Ceftibuten evoked inward currents in PEPT 1-expressing oocytes but not in water-injected oocytes, showing that the transport of the anionic cephalosporin via PEPT 1 is associated with transfer of positive charge . The ceftibuten-evoked currents were saturable with respect to ceftibuten concentration and were markedly dependent on membrane potential . It is concluded that anionic cephalosporins interact with the peptide transporters expressed in the intestine (PEPT 1) as well as in the kidney (PEPT 2). J Chromatogr B Biomed Sci Appl, 1997 Mar 7, 690(1-2), 321 - 6 Application of capillary zone electrophoresis in cephalosporin analysis; Mrestani Y et al.; Cephalosporins have structures and antibiotic activity similar to those of penicillins which represent a class of compounds with closely related structures . Most of the cephalosporins contain aromatic groups and show distinctive UV spectra . Separating the different types of cephalosporins is a challenging task for HPLC . but the resolving power of capillary zone electrophoresis (CZE) makes this separation fast and simple . The present study reports the application of CZE for cephalosporin analysis and the separation of cephalosporins from plasma . Both field strength and temperature were shown to influence the plate number . The influence of injection time on the peak height was studied . Furthermore, the influence of pH value on the separation of cephalosporins by CZE was investigated . The low sample amount required and the relatively short analysis time are the main advantages of this method. Diagn Microbiol Infect Dis, 1997 Mar, 27(3), 99 - 101 Use of ceftizoxime screening for the detection of cephalosporin-resistant pneumococci; Schutze GE et al.; Two hundred and ten pneumococcal isolates underwent ceftizoxime disk (30 micrograms) screening to predict cephalosporin resistance . Forty-six isolates failed screening with 36 (78%) demonstrating intermediate/resistant MICs . Sensitivity and specificity were 100 and 95%, respectively . The ceftizoxime disk screen is an effective method of identifying potentially cephalosporin-resistant isolates. Clin Infect Dis, 1997 Mar, 24(3), 487 - 93 The evolution of resistance to cephalosporins; Moosdeen F; The expression of resistance to cephalosporins is highly varied and due to various mechanisms . The greatest disadvantage of the cephalosporins is that they are inactivated by the array of beta-lactamases produced by bacteria . The high levels of chromosomal enzymes produced by these organisms are a major cause of cephalosporin resistance . Plasmid-mediated beta-lactamases (PMBLs) have also been implicated as causes of resistance, and other cephalosporinases have been described . Point mutations of specific amino acids of well-recognized PMBLs (e.g., TEM-1 and SHV-1) have also produced enzymes capable of attacking a wider spectrum of beta-lactam agents . The availability of newer beta-lactams may be conducive to the development of such beta-lactamases, in which chromosomal and newer plasmid derivatives that may or may not contain the AmpC gene are selected . The occurrence of such enzymes is likely to continue to increase. Ann Pharmacother, 1997 Feb, 31(2), 180 - 4 Hypoprothrombinemia associated with cefmetazole; Breen GA et al.; OBJECTIVE: To report a case of hypoprothrombinemia associated with the use of cefmetazole sodium, define patients at risk for this adverse effect, and identify options to prevent this problem . CASE SUMMARY: A malnourished patient with endstage renal disease received cefmetazole following a below-the-knee amputation of the right leg . Three days later, a prothrombin time (PT) and an international normalized ratio (INR) were obtained and were markedly elevated from baseline; however, the patient had no clinical symptoms of bleeding . Cefmetazole was discontinued . Vitamin K and fresh frozen plasma were administered . The PT and INR normalized within 24 hours and remained normal throughout the remainder of hospitalization . DISCUSSION: The incidence of hypoprothrombinemia associated with cefmetazole reported in the literature is conflicting and not consistent . There are three proposed mechanisms of cephalosporin-associated hypoprothrombinemia, two of which involve the N-methylthiotetrazole (NMTT) chain . The most plausible mechanism is NMTT inhibition of vitamin K epoxide reductase in the liver . Patients at an increased risk for this adverse event include those with low vitamin K stores, specifically patients who are malnourished, with low albumin concentrations and poor food intake . The elderly and patients with liver or renal dysfunction are examples of populations at risk . CONCLUSIONS: Hypoprothrombinemia may occur with cephalosporins and is especially problematic with those containing an NMTT side chain . Clinicians need to identify patients at risk for developing antibiotic-associated hypoprothrombinemia, monitor them closely, and give vitamin K as prophylaxis accordingly. Am J Physiol, 1997 Jan, 272(1 Pt 2), R217 - 25 H(+)-glycyl-L-proline cotransport in brush-border membrane vesicles of eel (Anguilla anguilla) intestine; Maffia M et al.; A plasma membrane H(+)-glycyl-L-proline (Gly-L-Pro) cotransport mechanism has been identified in isolated eel intestinal brush-border membrane vesicles (BBMV) by both measuring radiolabeled Gly-L-Pro uptake and monitoring Gly-L-Pro-dependent H+ influx with the pH-sensitive dye acridine orange . The application of an inside negative membrane potential resulted in increasing Gly-L-Pro uptake, as well as the application of inwardly directed H+ gradient (although only when an inside negative membrane potential was present) . Furthermore, vesicular H+ influx was found specifically associated with the presence of Gly-L-Pro in the extravesicular medium . The carrier-mediated nature of H(+)-Gly-L-Pro cotransport was assessed, and its concentration that yielded one-half maximal Gly-L-Pro influx was approximately 1.30 mM when measured by either radioactive or fluorescent tracers . Different dipeptides strongly inhibited Gly-L-Pro uptake by eel intestinal BBMV, as well as the cephalosporin antibiotic cephalexin, suggesting that dipeptide molecules and cephalosporin antibiotics may share a common transport system in eel intestinal BBMV. Clin Chest Med, 1996 Dec, 17(4), 767 - 85 Approach to the patient with pulmonary disease; Vander Els NJ et al.; The approach to the HIV-infected patient with pulmonary disease is summarized by the algorithms in Figures 3 and 4 . These are not intended to be followed in a rigid step-wise fashion . Rather, the practitioner's knowledge of the patient with his or her accompanying medical risks influences the path taken, including the depth and the speed of the evaluation . For example, the patient with cough who is afebrile and breathing at 18 breaths a minute, with a normal chest radiograph and a CD4 count of 350 cells/mm3, is reasonably treated with a macrolide or cephalosporin for bacterial bronchitis and clinical follow-up while awaiting cultures (see Fig . 4) . A febrile patient with a cough productive of thin mucus, but known to have a CD4 count of 60 cells/mm3 should be started on anti-PCP therapy while being evaluated for PCP with an induced sputum and if nondiagnostic, a bronchoscope despite a normal chest radiograph . Screening can be as simple as placing an oximeter on the patient's finger in the clinic . If the oxygen saturation of a patient with a normal chest radiograph is low, then the patient should be hospitalized and begun on treatment for PCP while diagnostic evaluation is initiated . If the oxygen saturation is normal, the patient can be exercised to elicit desaturation . If there is no desaturation, PCP is unlikely . If the results are equivocal (i.e., a decrease in saturation, but less than 3%), rest and exercise arterial blood gases can be performed, along with a Dlco-Gallium scanning can be done in patients known to have abnormal Dlco or those who cannot exercise . Patients with focal infiltrates who have acute onset of symptoms (see Fig . 4) commonly have bacterial infections, but the possibility of PCP or TB should not be dismissed . Induced sputum should be examined if TB or PCP is suspected . Patients who are severely ill might go quickly to bronchoscopy without awaiting improvement on empiric therapy . The patient with diffuse infiltrates (see Fig . 4) needs no screening because the presence of disease is apparent from the radiograph . The diagnostic part quickly leads to bronchoscopy for these patients and the initiation of therapy for PCP when suspected . In patients with known pulmonary KS, gallium scanning can be helpful to rule out acute infection, but bronchoscopy is warranted if the patient is severely ill, or at high risk for PCP . This approach should avoid unnecessary procedures in patients with simple bacterial infections, without missing opportunistic infections and tumors. Clin Pharmacol Ther, 1996 Dec, 60(6), 645 - 50 Multiple-dose pharmacokinetics of cefpirome in long-term hemodialysis with high-flux membranes; Thalhammer F et al.; Cefpirome is a cephalosporin eliminated primarily by kidneys that requires dosage reduction in patients with renal failure . The pharmacokinetic parameters were studied in 10 patients with end-stage renal disease who were receiving hemodialysis . Repeated intravenous administration of 2 gm cefpirome three times a week resulted in trough levels of 12.2 +/- 5.4 micrograms/ml and peak serum concentrations of 99.6 +/- 82.1 micrograms/ml . After 3 1/2 hours of hemodialysis with polysulfone high-flux membranes, 62.3% +/- 23.3% of cefpirome was removed . The interdialytic half-life was 9.35 +/- 0.99 hours, and the intradialytic half-life was 2.02 +/- 0.7 hours. Clin Ther, 1996 Nov-Dec, 18(6), 1139 - 49 Comparative bioavailability of ceftibuten in capsule and suspension forms; Lin CC et al.; The comparative bioavailability of ceftibuten, a new third-generation cephalosporin antibiotic given orally once daily, in capsule and suspension dosage forms, was assessed in healthy male subjects . In three separate studies, subjects received either a 400-mg dose as a suspension or one laboratory-batch, 400-mg capsule; one laboratory-batch, 400-mg capsule or two laboratory-batch, 200-mg capsules; or one production-batch, 400-mg capsule or two laboratory-batch, 200-mg capsules . Plasma samples were assayed for ceftibuten using high-performance liquid chromatography, and the data were assessed using pharmacokinetic and statistical methods . Confidence intervals for the maximum plasma concentration and the area under the plasma concentration-time curve extrapolated to infinity were within 80% to 125% of guidelines, demonstrating the bioequivalence of the two treatments within each of the three studies . One 400-mg capsule (laboratory or production batch) was bioequivalent to two 200-mg capsules used in a clinical efficacy trial; the 400-mg suspension was bioequivalent to a 400-mg capsule (laboratory batch) . Thus we concluded that the capsule and the suspension dosage forms were bioequivalent. J Biotechnol, 1996 Nov 1, 51(2), 137 - 48 The inhibitory mechanisms of glucose and carbon dioxide on the biosyntheses of penicillins and cephalosporins; Yang ZF et al.; The inhibitory mechanism of glucose and CO2 on the biosyntheses of penicillins and cephalosporins is discussed in the present paper . 6-aminopenicillanic acid (6-APA) is considered to be an intermediate product, and the reaction between 6-APA and glucose may play an important role in the yield and rate of biosyntheses of beta-lactam antibiotics . According to this hypothesis the experimental phenomena taking place in biosynthesis of penicillin and cephalosporin, such as the inhibition by glucose and carbon dioxide and the reduction of the yield, can be satisfactorily explained . The stability of 6-aminopenicillanic acid (6-APA) in bicarbonate solution, the reaction of 6-APA with sugars, the determination of the concentration of the 6-APA-sugar compound and the effect of these reactions on the biosynthesis of penicillin G are investigated to present evidences for this hypothesis. Minerva Med, 1996 Oct, 87(10), 479 - 85 {Effectiveness of and tolerance to ceftibuten in the treatment of chronic bacterial bronchitis exacerbations in an elderly population}; Allegra L et al.; 117 patients suffering for bacterial exacerbation of chronic bronchitis were treated with ceftibuten, a new orally administered cephalosporin, at the dosage of 400 mg once a day for 7.9 days (range 5-14) . The results, referring to 105 evaluable patients, underlyne ceftibutent's efficacy (good clinical results in 96.1% of 102 treated patients) and safety; before and after treatment values of spirometric tests were notable in terms of improvement of lung functions. J Pharm Biomed Anal, 1996 Oct, 15(1), 49 - 61 Quantitation of cefepime.2HCl dihydrate in cefepime.2HCl monohydrate by diffuse reflectance IR and powder X-ray diffraction techniques; Bugay DE et al.; The identification, characterization and quantitation of crystal forms is becoming increasingly important within the pharmaceutical industry . Multi-disciplinary, physical analytical techniques are necessary for this task . In this work, diffuse reflectance mid-infrared (IR) and powder X-ray diffraction (XRD) analyses were used to identify two different hydrated forms of cefepime.2HCl, a cephalosporin . Characterization of the mono- and dihydrate forms led to separate IR and XRD quantitative assays for the determination of dihydrate content in cefepime.2HCl monohydrate bulk material . For the IR assay, a working range of 1.0-8% (w/w) was established with a minimum quantifiable level (MQL) of 1.0% (w/w) and a limit of detection (LD) of 0.3% (w/w) dihydrate in monohydrate material . The XRD assay displayed a working range of 2.5-15% (w/w) with an MQL of 2.5% (w/w) and an LD of 0.75% (w/w) . Cross validation was performed between the two techniques, with a good correlation displayed for each assay as compared with the known concentrations and as compared with each other . In addition, a full evaluation of potential assay errors was made. J Biol Chem, 1996 Sep 13, 271(37), 22538 - 45 Selection and characterization of amino acid substitutions at residues 237-240 of TEM-1 beta-lactamase with altered substrate specificity for aztreonam and ceftazidime; Cantu C III et al.; Recently, natural variants of TEM-1 beta-lactamase with amino acid substitutions at residues 237-240 have been identified that have increased hydrolytic activity for extended-spectrum antibiotics such as ceftazidime . To identify the sequence requirements in this region for a given antibiotic, a random library was constructed that contained all possible amino acid combinations for the 3-residue region 237-240 (ABL numbering system) of TEM-1 beta-lactamase . An antibiotic disc diffusion method was used to select mutants with wild-type level activity or greater for the extended-spectrum cephalosporin ceftazidime and the monobactam aztreonam . Mutants that were selected for optimal ceftazidime hydrolysis contained a conserved Ala at position 237, a Ser for Gly substitution at position 238, and a Lys for Glu at position 240 . Mutants selected for aztreonam hydrolysis exhibited a Gly for Ala substitution at position 237, a Ser for Gly substitution at position 238, and a Lys/Arg for Glu at position 240 . The role of the A237G substitution in differentiating between ceftazidime and aztreonam was further investigated by kinetic analysis of the A237G, E240K, G238S:E240K, and A237G:G238S:E240K enzymes . The A237G single mutant and the G238S:E240K double mutant exhibited increases in catalytic efficiency for both ceftazidime and aztreonam . However, the triple mutant A237G:G238S:E240K, displayed a 12-fold decrease in catalytic efficiency for ceftazidime but a 3-fold increase for aztreonam relative to the G238S:E240K double mutant . Thus, the A237G substitution increases ceftazidime hydrolysis when present alone but antagonizes ceftazidime hydrolysis when it is combined with the G238S:E240K substitutions . In contrast, the A237G substitution acts additively with the G238S:E240K substitutions to increase aztreonam hydrolysis. Microbiologia, 1996 Sep, 12(3), 359 - 70 Recombinant Acremonium chrysogenum strains for the industrial production of cephalosporin; Diez B et al.; Conventional strain improvement programs based on random mutagenesis and rational screening have meant valuable results to the antibiotic producing companies . The development of recombinant DNA techniques and their applications to the industrially-used cephalosporin-producing fungus Acremonium chrysogenum has provided a new tool, complementary to classical mutation, promoting the design of alternative biosynthetic pathways making it possible to obtain new antibiotics and to improve cephalosporin production . Yield increases have been achieved by increasing the dosage of the biosynthetic genes cefEF (deacetoxycephalosporin C expandase/hydroxylase) and cefG (deacetylcephalosporin C acetyltransferase) or enhancing the oxygen uptake by expressing a bacterial oxygen-binding heme protein (Vitreoscilla hemoglobin) . New biosynthetic capacities such as the production of 7-aminocephalosporanic acid (7-ACA) or penicillin G have been achieved through the expression of the foreign genes dao (D-amino acid oxidase) coupled with cephalosporin acylase or penDE(acyl-CoA:6-APA acyltransferase) respectively . Confined manipulation of the above-mentioned recombinant strains must be performed according to standing rules. J Pharm Sci, 1996 Sep, 85(9), 984 - 9 Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution . 2 . Hydrolytic degradation pathway and mechanism for beta-lactam ring opened lactones; Okamoto Y et al.; Hydrolysis of cefdinir leads to pH-dependent isomerizations and beta-lactam ring-opening . Lactam ring opened gamma-lactones were produced as a mixture of four diastereoisomers based on the lactone methyl, and C-6 isomerizations in acidic to neutral solutions . Cefdinir and its 7-epimer were hydrolyzed to clarify the pathway leading to these lactones and the mechanism of C-6 epimerization with the aid of chiral separation techniques . Chiral separation using a bovine serum albumin column was employed to detect the beta-lactam ring opened products of cefdinir and its 7-epimer; the C-6 and C-7 isomerization was thereby observed; however, it was found to be pH-dependent at pH > or = 9 . Optical activity detection applied to the lactones produced from cefdinir and its 7-epimer demonstrated that the corresponding peaks of these lactones were enantiomeric pairs . In addition, the smallest rate constant at pH 4 was observed for C-6 epimerization of the lactones, and it was found to proceed without deprotonation at C-6 by 1H-NMR spectroscopy . From the results of these studies, a plausible mechanism for C-6 epimerization has been proposed . Additionally, it was confirmed that two degradation pathways were involved during hydrolysis of cefdinir to the lactone. J Pharm Sci, 1996 Sep, 85(9), 976 - 83 Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution . 1; Okamoto Y et al.; Hydrolytic degradation products of cefdinir were studied in acidic (pH 1), neutral (pH 6), and basic (pH 9) solutions . Seven major degradation products were isolated by preparative and/or high-performance liquid chromatography and characterized by UV, IR, 1H-NMR, and mass spectra . To clarify degradation pathways in each pH solution, kinetic and product analyses during hydrolysis of cefdinir were carried out along with the followup reaction of representative degradation products . Cefdinir was shown to degrade via two major degradation routes: beta-lactam ring-opening and pH-dependent isomerizations (lactonization, epimerization at C-6 or C-7, syn-anti isomerization of N-oxime function). J Allergy Clin Immunol, 1996 Sep, 98(3), 671 - 7 Cross-reactivity between a penicillin and a cephalosporin with the same side chain; Miranda A et al.; BACKGROUND: The cross-reactivity between penicillins and cephalosporins can be influenced by different factors, which are not all well known . The chemical structure of the side chain may contribute to the cross-reactivity . OBJECTIVE: The study was carried out in allergic subjects who are selectively responsive to amoxicillin to determine allergenic cross-reactivity with a cephalosporin containing a side chain identical to that of amoxicillin, cefadroxil, and one containing a different side chain, cefamandole . METHODS: Allergic subjects with a selective response to amoxicillin were chosen according to the following criteria: history of an immediate allergic reaction to amoxicillin, negative skin test responses to benzylpenicilloyl and minor determinant mixture of benzylpenicillin, negative RAST response to benzylpenicilloyl, and good tolerance to benzylpenicillin and phenoxymethyl penicillin challenges . In addition, subjects had to have a positive skin test response to amoxicillin and/or positive RAST response to amoxicilloyl or, if these test results were negative, a positive challenge test response to amoxicillin . In vivo cross-reactivity to cefadroxil was assessed by giving oral cefadroxil at increasing doses from 5 to 500 mg . In vitro cross-reactivity was determined by RAST inhibition studies with amoxicilloyl RAST disks and the following monomeric conjugates in the fluid phase: amoxicillin-butylamine, cefadroxil-butylamine, and the side chain para-hydroxy-phenylglycine . Tolerance to cefamandole was determined by giving 100 mg and then 500 mg parenterally . RESULTS: Twenty-one patients with a selective response to amoxicillin were included in the study . Eight subjects (38%) had a positive response to cefadroxil, and none reacted to cefamandole . In vitro RAST inhibition studies indicated that cefadroxil-butylamine monomers cross-reacted with amoxicillin butylamine and the side chain contributed relevantly to the inhibition . CONCLUSIONS: These results indicate that the percentage of cross-reactivity between penicillins and cephalosporins with an identical side chain is high and that this critical part of the molecule seems to be an important contributor to these results . The value is higher than previously reported data from similar studies of non-side-chain-related cephalosporins. J Biotechnol, 1996 Jul 18, 48(1-2), 59 - 66 Effect of oxygen on the respiratory system and cephalosporin-C production in Acremonium chrysogenum; Kozma J et al.; In this paper in vivo studies on the overall and cyanide-resistant respiration of Acremonium chrysogenum in connection with different oxygen transfer rates are discussed . Two parameters of the cyanide-resistant respiration, the activity and the capacity were examined separately during cultivation together with the possibly respiration-influencing factors like NADH/NAD content and ADP-limitation . It was finally concluded that the cyanide-resistant respiration seems to be independent of the amount and proportion of oxidized/reduced coenzymes and not limited by ADP or phosphate, but it is strongly affected by the oxygen available . It was also established that the examined path must have an important role in cephalosporin-C overproduction. J Mol Recognit, 1996 Jul-Aug, 9(4), 287 - 96 beta-Lactam drug allergens: fine structural recognition patterns of cephalosporin-reactive IgE antibodies; Pham NH et al.; Lack of experimental findings on the spectrum of cephalosporin allergenic determinants has hindered diagnosis of adverse reactions to these drugs and retarded understanding of allergenic cross-reactions between cephalosporins and between cephalosporins and penicillins . Subjects allergic to the widely used cephalosporin antibiotic cefaclor have serum immuno globulin (Ig) E antibodies that react with the drug . Quantitative hapten inhibition studies employing sera from subjects allergic to cefaclor revealed fine structural recognition differences between the combining site specificities of cefaclor-reactive IgE antibodies in the sera of different subjects . Unlike penicillins, where discrete side chain or thiazolidine ring determinants alone may be recognized, IgE binding determinants on cefaclor encompassed the entire molecule . Fine structural recognition specificity differences at positions R1 (side-chain) and R2 (substituent attached to dihydrothiazine ring) were detected between IgE antibodies in different sera . Some antibodies showed clear preferential recognition of the aminobenzyl group at position R1 and Cl at R2 while with others, a greater degree of recognition tolerance was seen at R1 where, for example, the aminohydroxybenzyl or aminodihydrobenzyl groups were recognized, and at R2 where a methyl or even an ester group was tolerated . As with the penicillins, cephalosporins as allergens cannot simply be considered as a group of compounds with a common allergenic determinant structure . IgE antibodies that bind to cefaclor show great heterogeneity indicated by clear, fine structural differences in recognition of the R1 and R2 groups on the drug. Am J Med, 1996 Jun 24, 100(6A), 68S - 75S Safety of cefepime: a new extended-spectrum parenteral cephalosporin; Neu HC; The purpose of this study was to compare the safety profile of cefepime, a new extended-spectrum, fourth-generation cephalosporin used to treat mild-to-severe bacterial infections, with that of ceftazidime . A total of 2,032 patients enrolled in North American and European cefepime trials were analyzed . The study population spanned adolescence to the elderly (15-100 years); the median age was 62 years . Cefepime was compared with ceftazidime (1,456 patients), a third-generation cephalosporin . Cefepime dosing was 1-4 g/day (0.5-2.0 g twice daily) for adults; ceftazidime dosing was 1-6 g/day (0.5 g every 12 hours to 2.0 g every 8 hours) . A limited number of cefepime-treated patients received 2 g every 8 hours . The median length of dosing for both cefepime and ceftazidime was 7 days . In randomized trials in which cefepime (2,032 patients) was compared with ceftazidime (1,456 patients), analysis of comparative data indicated that adverse events of probable or unknown relation to study drugs were observed in 13.8% of cefepime patients and 15.6% of ceftazidime patients . The most commonly observed adverse event for cefepime was headache (2.4%), followed by nausea (1.8%), rash (1.8%), and diarrhea (1.7%) . For ceftazidime, the most commonly observed adverse event was diarrhea (3.2%), followed by headache (2.5%), nausea (2.1%), rash (1.9%), and constipation (1.5%) . The incidence of positive Coombs' test was higher in high-dose cefepime recipients than in ceftazidime recipients (14.5% vs 8.7%; p = 0.043), although there was no evidence of hemolysis in either treatment group . Coadministration of analgesics, diuretics, and anticoagulants did not increase incidence of adverse events associated with study-drug therapy . Adverse renal and hematologic events, as well as anaphylaxis and death, were rare in both groups . In the comparative trials with cefepime, anaphylaxis was reported in no patients receiving cefepime and in one patient receiving ceftazidime . None of the three seizures reported in patients receiving cefepime and one of six seizures in patients receiving ceftazidime were of probable or possible relationship to the study drugs . None of the 12 cases of gastrointestinal hemorrhage reported in cefepime patients or five cases reported in ceftazidime patients were judged to be related to treatment drug . Tolerance for intravenous administration in both treatment groups was similar . Cefepime did not effect any significant or unusual allergic, hematologic, gastrointestinal, neurologic, or renal toxicity when administered to patients with mild-to-severe infections, including those receiving concomitant medications . The safety profile of cefepime is excellent and comparable to that of ceftazidime and those reported for other cephalosporins. Allergy, 1996 Jun, 51(6), 383 - 86 Clinical cross-reactivity between amoxicillin and cephadroxil in patients allergic to amoxicillin and with good tolerance of penicillin; Sastre J et al.; In recent years, patients allergic to amoxicillin (AX) but with good tolerance of penicillin G (PG) have been described . It has been suggested that the epitope implicated in this type of sensitization might be located on the side-chain of the AX molecule . Thus, cross-reactivity between AX and cephadroxil (CEPH), a cephalosporin which shares an identical side-chain with AX, is suspected . This study aimed to demonstrate clinical cross-reactivity between AX and CEPH in patients allergic to AX and showing good tolerance of PG . In 76 of 576 subjects with suspected allergic reaction to PG and/or AX, the diagnosis of allergy was confirmed . All of these had specific IgE to PG, penicillin V, or AX, and/or positive skin tests to PPL (penicilloyl-polylysine), or MDM (minor determinant mixture), or PG, or AX, and/or positive challenge tests with PG and/or AX . Sixteen subjects (21%) allergic to AX (11 with positive skin test and five with positive challenge test to AX) and good tolerance of PG (all with negative parenteral challenge test) were selected . These 16 patients were subsequently challenged with CEPH (up to 500 mg) . Fourteen patients tolerated CEPH, and two (12%) had an immediate allergic reaction . Our study indicates that allergy to the side-chain of aminopenicillins seems to have little clinical relevance in patients with allergic reactions to aminopenicillins but with good tolerance of PG, as 88% of patients with this clinical characteristic tolerate a cephalosporin which shares an identical side-chain . It seems that IgE from most of these patients recognizes an epitope different from the side-chain and the beta-lactam ring. Aust N Z J Med, 1996 Jun, 26(3), 386 - 90 An audit of third generation cephalosporin prescribing in a tertiary care hospital; LeMire M et al.; BACKGROUND: There is increasing resistance to commonly used antibiotics, including third generation cephalosporins, and an increasing cost burden . AIMS: To assess the appropriateness of prescribing of third generation cephalosporin antibiotics in a tertiary teaching hospital . METHODS: Prescriptions of third generation cephalosporins (ceftriaxone, cefotaxime and ceftazidime) to inpatients were identified prospectively by the Hospital Pharmacy Department for a six week period during May-June 1994 . Clinical data and indications were obtained from patient records and, when necessary, by interviewing the prescriber and by patient assessment . Criteria for appropriate prescribing were according to nationally accepted criteria outlined in the 1994-95 Antibiotic Guidelines handbook . All inpatients who were prescribed a third generation cephalosporin at Flinders Medical Centre for the duration of the audit period were eligible . This included medical, surgical, paediatric, obstetric and gynaecology inpatients . RESULTS: Sixty-five per cent of prescriptions for third generation cephalosporins were judged appropriate, 31% inappropriate and 4% doubtful . Inappropriate use was found particularly in the treatment of respiratory tract infections and abdominal sepsis, and in surgical prophylactic use . CONCLUSION: Third generation cephalosporin prescribing in a tertiary care teaching hospital is frequently inappropriate, as judged against widely available Australian guidelines. Appl Microbiol Biotechnol, 1996 Jun, 45(5), 621 - 8 Effect of amplification or targeted disruption of the beta-lactamase gene of Nocardia lactamdurans on cephamycin biosynthesis; Kumar V et al.; The bla gene of the cephamycin cluster of Nocardia lactamdurans has been subeloned in the shuttle plasmids pULVK2 and pULVK2A and amplified in N . lactamdurans LC411 . The transformants showed two- to threefold higher beta-lactamase activity . Formation of beta-lactamase preceded the onset of cephamycin biosynthesis . The beta-lactamase of N . lactamdurans inactivated penicillins and, to a lesser extent, cephalosporin C but did not hydrolyse cephamycin C . This beta-lactamase was highly sensitive to clavulanic acid (50% inhibition was observed at 0.48 microgram/ml clavulanic acid) . The N . lactamdurans bla gene was disrupted in vivo by inertion of the kanamycin-resistance gene . Three bla-disrupted mutants, BD4, BD8 and BD12, were selected that lacked beta-lactamase activity . Overexpresion of the bla gene resulted in N . lactamdurans transformants that were resistant to penicillin whereas mutants in which the bla gene was disrupted were super-sensitive to this antibiotic . The three N . lactamdurans mutants with the bla gene disrupted showed a significant increase of cephamycin biosynthesis in solid medium, whereas transformants with the amplified bla gene produced reduced levels of cephamycin . The cephamycin-overproducing Merck strain N . lactamdurans MA4213 showed no detectable levels of beta-lactamase activity . The beta-lactamase plays a negative role in cephamycin biosynthesis in solid medium, but not in liquid medium. Ann N Y Acad Sci, 1996 May 15, 782, 17 - 24 Metabolic engineering of cephalosporin biosynthesis in Streptomyces clavuligerus; Khetan A et al.; The biosynthesis of beta-lactams is one of the most thoroughly studied antibiotic pathways . The availability of the characteristics and the time profiles of activities of enzymes involved in the biosynthesis allows one to critically evaluate the potential rate-limiting steps in its production . Our approach to understanding the control of beta-lactam biosynthesis has been pursued using a two-stage strategy: (1) to predict the rate-limiting steps using a kinetic model and (2) to relax the rate-limiting steps by engineering the biosynthetic pathway or by altering the kinetic parameters of the predicted key rate-limiting enzyme . Kinetic analysis of the pathway dynamics of cephamycin C production in Streptomyces clavuligerus was performed using data obtained from wild type . Sensitivity analysis revealed that the availability of precursor alpha-aminoadipic acid and activity of ACV synthetase were the potential rate-limiting steps . Relaxation of the precursor limitation was accomplished by integration of an additional copy of the gene encoding lysine-epsilon-aminotransferase (lat) into the chromosome . The recombinant strain showed an increased level of cephamycin C production as expected . The intracellular levels of different intermediates in the pathway in batch cultures were analyzed. J Biol Chem, 1996 May 3, 271(18), 10482 - 9 Structural basis of extended spectrum TEM beta-lactamases . Crystallographic, kinetic, and mass spectrometric investigations of enzyme mutants; Maveyraud L et al.; The E166Y and the E166Y/R164S TEM-1 beta-lactamase mutant enzymes display extended spectrum substrate specificities . Electrospray mass spectrometry demonstrates that, with penicillin G as substrate, the rate-limiting step in catalysis is the hydrolysis of the E166Y acyl-enzyme complex . Comparison of the 1.8-A resolution x-ray structures of the wild-type and of the E166Y mutant enzymes shows that the binding of cephalosporin substrates is improved, in the mutant enzyme, by the enlargement of the substrate binding site . This enlargement is due to the rigid body displacement of 60 residues driven by the movement of the omega-loop . These structural observations strongly suggest that the link between the position of the omega-loop and that of helix H5, plays a central role in the structural events leading to extended spectrum TEM-related enzymes . The increased omega-loop flexibility caused by the R164S mutation, which is found in several natural mutant TEM enzymes, may lead to similar structural effects . Comparisons of the kinetic data of the E166Y, E166Y/R164S, and R164S mutant enzymes supports this hypothesis. Clin Chem, 1996 May, 42(5), 761 - 5 HPLC micromethod for amrinone and metabolites in patients receiving concurrent cephalosporin therapy; Pappas JB et al.; Amrinone (AMR), a bipyridine derivative, is receiving increasing use in postoperative cardiac patients as an inotrope and vasodilator . The hemodynamic response to amrinone in adults is linearly related to AMR concentrations, warranting therapeutic drug monitoring . We report a rapid microsample HPLC method for monitoring AMR and its principal metabolites, N-acetyl (N-ac) and N-glycolyl (N-gly) AMR . Serum was precipitated with acetonitrile, and the supernatant fluid was then injected into a C18 narrow-bore column . The mobile phase consisted of a 0.1 mol/L sodium phosphate buffer (pH 6) with a gradient of acetonitrile going from 50 to 100 mL/L of eluent . Detection with a diode-array detector (DAD) concurrently monitored the absorbances at 320 and 345 nm . Monitoring 320 nm allows optimal quantification of AMR, N-gly, and N-ac . Patients often receive concurrent cephalosporin therapy, which is detectable at 320 nm but not 345 nm . Because cephalosporins coelute with AMR or metabolites, monitoring at 345 nm allows separation of these antibiotics from AMR and metabolites while retaining a detection limit of 0.5 mg/L. Am Surg, 1996 May, 62(5), 336 - 8 Laparoscopic ventral hernia repair: a community hospital experience; Saiz AA et al.; From October 1993 to April 1994, laparoscopic ventral hernia repair was performed on 10 patients, all of whom had a history of failed ventral hernia repair and at least two prior ventral hernia repair procedures . Patients presented with complaints of abdominal discomfort, painful mass at the hernia site, or vague abdominal discomfort . No operative deaths occurred . Two patients had minor complications: a seroma at the repair site, which resolved spontaneously, and a superficial wound infection at a trochar site, which responded to an oral cephalosporin . Six patients were discharged within 24 hours of surgery and one patient was operated on as an outpatient and discharged the same day . Follow-up of all patients ranged from 10 to 17 months . No evidence of hernia recurrence has been noted . Some recurrent ventral hernias are amenable to laparoscopic repair, and this technique may be preferable in some patients, especially those who have had an earlier failed open repair with mesh . We do not advocate use of our technique for the first repair of a ventral hernia . Long-term follow-up is still needed to determine recurrence rates compared with conventional open techniques. FEMS Microbiol Lett, 1996 Apr 1, 137(2-3), 135 - 40 An inducible expression system of histidine-tagged proteins in Streptomyces lividans for one-step purification by Ni2+ affinity chromatography; Enguita FJ et al.; An expression and purification cassette containing the aminoglycoside phosphotransferase gene (aph) as selective marker has been constructed in the Escherichia coli vector pULHis2 . DNA fragments inserted in the cassette can be easily subcloned in pIJ699 to give vectors for overexpression of genes in Streptomyces and purification of proteins by a one-step procedure . The expression system uses the thiostrepton-inducible promoter tipA for expression and a six histidine coding nucleotide sequence that is fused in frame to the foreign gene inserted in the polylinker . The pULHis2-derived expression vector has been used satisfactorily to express and to purify the P7 and P8 proteins of Nocardia lactamdurans which carry out the methoxylation of cephalosporin C to 7-methoxycephalosporin C. Biochem Pharmacol, 1996 Feb 23, 51(4), 557 - 61 Cephalosporin and carbacephem nephrotoxicity . Roles of tubular cell uptake and acylating potential; Tune BM et al.; Three beta-lactams, desacetylcephaloglycin, ampicillin, and loracarbef, were studied to test a hypothesis derived from retrospective analysis of previously studied cephalosporins: that beta-lactam nephrotoxicity develops in approximate proportion to tubular cell antibiotic concentrations and lactam ring reactivities . Concentrations of each beta-lactam (and insulin) in rabbit renal cortex and serum were measured at the end of 0.5-hr infusions of 100 mg antibiotic/kg body weight and 0.5 to 0.67 hr later . Total cortical AUCs (total areas under the curve of concentration and time in renal cortex) and transported cortical AUCs (total minus insulin-space beta lactam) were calculated from these measurements . Reactivities, determined by the rate constants of lactam-ring opening at pH 10, were taken from the literature . Nephrotoxicity was quantified by grades of proximal tubular cell necrosis and by serum creatinine concentrations 2 days after infusion of 100-1500 mg/kg of the antibiotics . Desacetylcephaloglycin was slightly less nephrotoxic than cephaloglycin; the AUCs reactivities, and toxicities of these two cephalosporins fit the proposed model, particularly when allowance is made for hepatic and renal deacetylation of cephaloglycin . The very low AUCs, limited reactivity, and absence of nephrotoxicity of ampicillin also fit the model . Loracarbef had a transported AUC less than three times, and reactivity one-thirtieth, those of cefaclor, respectively . Although only at 1500 mg/kg, loracarbef was significantly more nephrotic than cefaclor . If the relativity of loracarbef with its targeted bacterial proteins, which is essentially the same as that of cefaclor, is considered instead of the base hydrolysis rate constant, than loracarbef also fits the model . By the same analysis, the comparatively high in vitro stability of other carbacephems, although pharmaceutically convenient, may not limit their nephrotoxicity. Cell Biol Toxicol, 1996 Feb, 12(1), 39 - 53 A cellular model for drug interactions on hematopoiesis: the use of human umbilical cord blood progenitors as a model for the study of drug-related myelosuppression of normal hematopoiesis; Leglise MC et al.; A cellular model of hematopoiesis which would be more convenient than bone marrow (BM) progenitors and directly relevant to human pathology is needed in order to investigate xenobiotic toxicity . Human umbilical cord blood (HCB), previously shown to be able to repopulate BM, provides a powerful in vitro model of normal human hematopoiesis . In order to validate the use of normal HCB progenitors as targets for dose-related myelosuppression, we used clonogenic assays and expansion in a liquid culture of progenitor-enriched cell suspensions from HCB . A series of 8 reference molecules, doxorubicin, cytosine-arabinoside, 5-fluorouracil, 3'-azido-3'-deoxythymidine, acetylsalicylic acid, sodium valproate and two cephalosporin antibiotics, were tested . In vitro 50% inhibition concentrations (IC50) were compared to those observed or reported with BM progenitors, and to the values of plasma concentrations from treated patients . HCB progenitors as in vitro targets for cytotoxic molecules were easy to access and handle, and their use was sensitive, specific and reproducible . They gave results similar to BM progenitors and allowed a qualitative approach to cellular metabolism and toxicity using morphological, flow cytometric and chromatographic methods. Antimicrob Agents Chemother, 1996 Feb, 40(2), 481 - 4 Activities of RPR 106972 (a new oral streptogramin), cefditoren (a new oral cephalosporin), two new oxazolidinones (U-100592 and U-100766), and other oral and parenteral agents against 203 penicillin-susceptible and -resistant pneumococci; Spangler SK et al.; Agar dilution was used to determine the MICs of RPR 106972 (a new oral streptogramin), cefditoren (a new oral cephalosporin), two new oxazolidinones (U-100592 and U-100766), and other oral and parenteral agents for 203 penicillin-susceptible and -resistant pneumococci . All pneumococci were inhibited by RPR 106972 at < or = 0.5 microgram/ml . Cefditoren was very active against all pneumococcal groups, with MICs of < or = 2.0 micrograms/ml . Amoxicillin with or without clavulanate was the next most active oral beta-lactam, followed by cefdinir, cefuroxime, cefpodoxime, and cefprozil . U-100592 and U-100766 were very active against all classes of pneumococci, with all MICs < or = 1.0 microgram/ml. Free Radic Biol Med, 1996, 21(6), 827 - 32 Attack of cefotaxime by different radicals: comparison of the effects; Crucq AS et al.; Free radicals are physiological products and can react to administrated drugs . Metabolic transformations by radical mechanisms are, therefore, possible . A fundamental study of radio-induced degradation of aqueous solutions of sodium cefotaxime, a third generation cephalosporin, was realized to describe these possible radical mechanisms . Different radicals produced by the radiolysis method (.OH, N3., Br2.-, Tbut., eaq- + .OH, and exq- + Tbut.) were successively used to induce the radical mechanisms and their effects were compared . All these radicals induce the formation of a same main radiolysis product identified as anticefotaxime . Radical mechanisms induced by N3., Tbut., and eaq- include chain reactions to explain the formation of anticefotaxime contrary to those induced by .OH and Br2.-. Fundam Clin Pharmacol, 1996, 10(3), 309 - 13 Influence of lipophilicity on the diffusion of cephalosporins into the cerebrospinal fluid; Radouane A et al.; The aim of this quantitative structure-activity relationship (QSAR) study was to investigate the influence of lipophilicity on the diffusion of cephalosporins into the cerebrospinal fluid (CSF) . The lipophilicity was expressed as the chromatographic capacity factor (log k'w) determined by high-performance liquid chromatography in a reversed-phase system . The penetration of eight cephalosporins into CSF was studied in male Wistar rats receiving the drugs intramuscularly (1.5 mg/kg) . One hour after administration, CSF and blood samples were collected, and concentrations of free drug were measured in CSF (CCSF) and in plasma (CP) . A significant parabolic relationship was sought between lipophilicity (log k'w) and the capacity of diffusion across the blood-brain barrier expressed as log (CCSF/CP) . The cephalosporins exhibiting a moderate lipophilicity diffused well into CSF . A pharmacokinetic study was performed at 1, 2 and 4 h after administration of three cephalosporins: cefazolin, ceftriaxone and cefsulodin . These compounds were choosen according to their lipophilicities (low, moderate and high values, respectively) . The AUC0-4h for both free plasma (AUCP) and cerebrospinal fluid (AUCCSF) concentrations were determined . The AUCCSF/AUCP ratio presented a maximum value for a strongly albumin bound cephalosporin, ceftriaxone . In our experimental conditions, the ideal lipophilicity (log k'w) range for diffusion of cephalosporins from plasma into CSF was between 1.6 and 1.8. Antimicrob Agents Chemother, 1996 Jan, 40(1), 102 - 4 Pharmacokinetics of cefetamet in plasma and skin blister fluid; Zimmerli W et al.; Cefetamet pivoxil is an oral cephalosporin with enhanced affinity for the target penicillin-binding proteins 1 and 3 and an increased stability to beta-lactamases compared with older cephalosporins, such as cefalexin or cefaclor . The pharmacokinetics of cefetamet pivoxil was determined after the seventh and final dose of 500 mg of cefetamet pivoxil in eight healthy volunteers . Concentrations in plasma and cantharidin-induced skin blister fluid were determined by a high-performance liquid chromatography method . In addition, protein binding was assessed . Cmax was 4.8 +/- 1.7 micrograms/ml in skin blister fluid and 5.1 +/- 2.1 micrograms/ml in plasma . Tmax was delayed in skin blister fluid compared with plasma (3.9 +/- 1 versus 2.8 +/- 0.8 h; P < 0.001), and t1/2 was longer in skin blister fluid than in plasma (3.1 +/- 0.5 versus 2.3 +/- 0.3; P < 0.005) . The mean percent penetration into cantharide blister fluid was 129% +/- 24% when measured as total drug and 149% +/- 28% when measured as free drug (P < 0.001) . These data suggest that cefetamet has an excellent penetration into inflammatory interstitial fluid. Appl Microbiol Biotechnol, 1996 Jan, 44(5), 589 - 96 Molecular analysis of the gene cluster involved in cephalosporin biosynthesis from Lysobacter lactamgenus YK90; Kimura H et al.; Determination of the nucleotide sequence downstream from the Lysobacter lactamgenus pcbC gene encoding isopenicillin N synthase revealed that five open-reading frames (ORF) including the pcbC gene were tightly linked in the same orientation . Each ORF has the remarkable feature of the protein-coding frame in the DNA sequence with a high G+C content . Expression in Escherichia coli and a comparison of the deduced amino acid sequences with published sequences showed that the gene cluster contained a deacetoxycephalosporin C synthetase (DAOCS) gene (cefE), an ORF having homology with the Cephalosporium acremonium DAOCS/deacetylcephalosporin C synthetase gene (cefEF), an isopenicillin N epimerase gene(cefD), and a beta-lactamase gene . The gene order was pcbC-cefE-ORF3-cefD-beta-lactamase. Acad Med, 1996 Jan, 71(1), 86 - 8 When pharmaceutical manufacturers' employees present grand rounds, what do residents remember? Spingarn RW, Berlin JA, Strom BL. PURPOSE . To evaluate the educational effect on residents of a grand rounds given by a pharmaceutical company employee . METHOD . Using a retrospective cohort study design, the authors questioned 75 housestaff at a university hospital three months after a February 1990 grand rounds on Lyme disease to determine whether the residents' beliefs about the drug of choice for this disease differed between attendees and non-attendees . Odds ratios, 95% confidence intervals, and logistic regression were used for the analysis of results . RESULTS . The 22 housestaff who had attended the grand rounds were more likely to choose appropriately the cephalosporin manufactured by the speaker's company over other drugs for patients with Lyme disease presenting with second-degree heart block (adjusted odds ratio of 8.4; 95% CI 2.1-38.9) . However, they also chose it inappropriately for first-degree heart block (adjusted odds ratio of 7.8; 95% CI 1.6-45.5) . None of the attendees, compared with 11 (21%) of the non-attendees, named an oral antibiotic for both of two milder presentations, even though oral therapy would be more appropriate (p = .027) . CONCLUSION . The results suggest that grand rounds effectively change residents' beliefs, but a sponsoring company's drug may be favored . Information assimilated in this way may not be well supported by the scie