Quantifying the importance of active antimicrobial therapy among patients with Gram-negative bloodstream infections: Cefepime as a representative agent.

The quantitative importance of active antimicrobial treatment relative to other modifiable and non-modifiable risk factors for mortality has not been well defined in the literature. Here we quantify the impact of active antimicrobial treatment on mortality relative to other disease modifiers in patients with Gram-negative bloodstream infection (GNBSI). Patients with at least one positive blood culture who were treated with ≥24 h of cefepime for GNBSI were included in the study. To examine in-hospital survival, a full primary model and a base model with the least significant covariate from the primary model were established. Relative importance of covariates was calculated using percentages of difference in log-likelihood values when each covariate was iteratively added to the base model. A total of 154 unique patients with GNBSI were included. The primary model included active cefepime therapy (P = 0.004), normalised days to positive culture (P = 0.091), intensive care unit (ICU) at time of treatment (P = 0.001), modified Acute Physiology and Chronic Health Evaluation (APACHE) II score on day zero (P = 0.025), history of leukaemia (P = 0.008) and prior immunosuppressive therapy (P = 0.088). Active antimicrobial therapy displayed a relative importance of 32.2%, which was second to ICU residence at the time of culture. Amongst all covariates in the model, active antimicrobial therapy was the only modifiable variable and contributed significantly to in-hospital survival in acutely ill patients with GNBSI.

High-Performance Liquid Chromatography Method for Rich Pharmacokinetic Sampling Schemes in Translational Rat Toxicity Models With Vancomycin.

A translational need exists to understand and predict vancomycin-induced kidney toxicity. We describe: (i) a vancomycin high-performance liquid chromatography (HPLC) method for rat plasma and kidney tissue homogenate; (ii) a rat pharmacokinetic (PK) study to demonstrate utility; and (iii) a catheter retention study to enable future preclinical studies. Rat plasma and pup kidney tissue homogenate were analyzed via HPLC for vancomycin concentrations ranging from 3-75 and 15.1-75.5 µg/mL, respectively, using a Kinetex Biphenyl column and gradient elution of water with 0.1% formic acid: acetonitrile (70:30 v/v). Sprague-Dawley rats (n = 10) receiving 150 mg/kg of vancomycin intraperitoneally had plasma sampled for PK. Finally, a catheter retention study was performed on polyurethane catheters to assess adsorption. Precision was <6.1% for all intra-assay and interassay HPLC measurements, with >96.3% analyte recovery. A two-compartment model fit the data well, facilitating PK exposure estimates. Finally, vancomycin was heterogeneously retained by polyurethane catheters.

Relationship between vancomycin exposure and outcomes among patients with MRSA bloodstream infections with vancomycin Etest® MIC values of 1.5mg/L: A pilot study.

Data suggest that vancomycin is less effective for methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) with vancomycin Etest® MIC (MICEtest) ≥1.5 mg/L. No published studies have evaluated the relationship between vancomycin exposure and outcomes among patients with MRSA BSIs vancomycin MICEtest ≥1.5 mg/L. This study was a retrospective cohort of 71 hospitalized, adult, non-dialysis patients with MRSA BSIs treated with vancomycin. All but three patients had a vancomycin MICEtest of 1.5 mg/L. Achievement of CART-derived AUC24-48h of at least 550 mg*h/L (AUC24-48h/MIC of 366 mg*h/L) was associated with a lower incidence of treatment failure. In multivariate analyses, the risk ratio was 0.45 for the CART-derived AUC24-48h threshold, indicating that achievement of the CART-derived AUC24-48h threshold of 550 was associated with a 2-fold decrease in treatment failure. These findings suggest a potential association between vancomycin exposure and outcomes in patients with MRSA BSIs with MICEtest ≥1.5 mg/L. As this study was retrospective, these findings provide the basis for a future large-scale, multi-center prospective study.

Resolution of acyclovir-associated neurotoxicity with the aid of improved clearance estimates using a Bayesian approach: A case report and review of the literature.

WHAT IS KNOWN AND OBJECTIVE: Neurotoxicity is a side effect of acyclovir. We report the first case, to our knowledge, whereby Bayesian-informed clearance estimates supported a therapeutic intervention for acyclovir-associated neurotoxicity. CASE SUMMARY: A 62-year-old male with the diagnosis of disseminated zoster was being treated with intravenous (IV) acyclovir when he developed symptoms of acute neurotoxicity. Acyclovir had been dose-adjusted for renal dysfunction according to traditional creatinine clearance estimates; however, as the patient was also on vancomycin, Bayesian estimates of vancomycin clearances were performed, which revealed a 2-fold lower creatinine clearance. In response to the Bayesian estimates, acyclovir was discontinued, and improvements in mentation were noted within 24 hours. WHAT IS NEW AND CONCLUSION: Alternate approaches to estimate renal function beyond Cockcroft-Gault, such as a Bayesian approach used in our patient, should be considered when population estimates are likely to be inaccurate and potentially dangerous to the patient.

The independent effect of body mass index on health-related quality of life among racial and ethnic subgroups.

PURPOSE: To evaluate the impact of race/ethnicity on the relationship between body mass index (BMI) and health-related quality of life (HRQOL) among blacks, Hispanics, and whites. METHODS: We used the Sinai Urban Health Institute's Improving Community Health Survey dataset to measure physical and mental HRQOL using the Physical Component Score (PCS-12) and the Mental Component Score (MCS-12) of the Short Form-12. Multivariate linear regression models were applied to the overall sample and in models stratified by race/ethnicity to evaluate the effects of BMI on physical and mental HRQOL outcome variables while controlling for confounders. RESULTS: Considering physical HRQOL, increasing BMI was independently associated with worse PCS-12 (ß = -0.22, p value <0.001) in the overall sample; the magnitude was not significantly different across racial/ethnic subgroups (blacks: ß = -0.18, p value = 0.02; Hispanics: ß = -0.28, p value = 0.01; whites: ß = -0.20, p value = 0.02). Overall, Hispanic participants reported a worse PCS-12 compared to whites (ß = -3.06, p value = 0.002). Considering mental HRQOL, BMI was not significantly associated with MCS-12 in the overall sample (ß = -0.06, p value = 0.21) nor was BMI significantly associated with MCS-12 in any racial/ethnic subgroups. Overall, black participants reported better MCS-12 compared to whites (ß = 2.51, p value = 0.001). CONCLUSIONS: BMI was associated with worse physical HRQOL to a similar degree among blacks, Hispanics, and whites. This finding suggests that interventions leading to obesity reduction should be associated with substantial and equal improvements in the physical HRQOL of all race/ethnicity groups.

Identification of optimal renal dosage adjustments for traditional and extended-infusion piperacillin-tazobactam dosing regimens in hospitalized patients.

This study examined the effect of various levels of renal impairment on the probability of achieving free drug concentrations that exceed the MIC for 50% of the dosing interval (50% fT > MIC) for traditional and extended-infusion piperacillin-tazobactam (TZP) dosing strategies. It also identified optimal renal dosage adjustments for traditional and extended-infusion dosing schemes that yielded probability of target attainment (PTA) and exposure profiles that were isometric to those of the parent regimens. Data from 105 patients were analyzed using the population pharmacokinetic modeling program BigNPAG. To assess the effect of creatinine clearance (CL(CR)) on overall clearance, TZP clearance was made proportional to the estimated CL(CR). A Monte Carlo simulation (9,999 subjects) was performed for the traditional dosing scheme (4.5 g infused during 30 min every 6 h) and the extended-infusion TZP dosing scheme (3.375 g infused during 4 h every 8 h). The fraction of simulated subjects who achieved 50% fT > MIC was calculated for the range of piperacillin MICs from 0.25 to 32 mg/liter and stratified by CL(CR). The traditional TZP regimen displayed the greatest variability in PTA across MIC values, especially for MIC values exceeding 4 mg/liter, when stratified by CL(CR). In contrast, the PTA for the extended-infusion TZP regimen exceeded >or=80% for MIC values of or=32 mg/liter irrespective of the CL(CR). The CL(CR) adjustments for traditional and extended-infusion TZP dosing regimens should be considered at a CL(CR) of

Tacrolimus use in adult allogeneic stem cell transplant recipients receiving voriconazole: preemptive dose modification and therapeutic drug monitoring.

Concomitant use of tacrolimus and voriconazole, both competitive inhibitors of the CYP450 3A4 isoenzyme, requires tacrolimus dose reduction. On the basis of clinical observations, we developed a preemptive dose-reduction strategy in allograft recipients who received voriconazole to maintain tacrolimus concentrations within a target range. A total of 27 patients started i.v. tacrolimus at an average daily dose of 0.022 mg/kg on day -1 (30% lesser than the usual starting dose). The dose was reduced by 30-40% if the 48-h steady-state concentration was 7-10 ng/ml, and by 40-50% if it was 10-15 ng/ml. No change was made if the concentration was <7 ng/ml. Subsequently, concentrations were generally monitored 2-3 times a week with dose adjustments as necessary. None of the 170 levels (3-12 per patient; median 5) obtained between days +1 and +16 were subtherapeutic (<5 ng/ml) and only 34 levels (20%) were >15 ng/ml. Each patient required dose reduction at least twice. The dose had to be increased in only two patients after the initial dose reduction. The median tacrolimus doses in mg/kg declined with time; being 0.022, 0.008 and 0.006 on days 0, 7 and 14, respectively. We conclude that a preemptive dose-reduction strategy is effective in maintaining tacrolimus concentrations within the desired therapeutic range, although serial monitoring remains prudent.

Breakthrough zygomycosis after voriconazole administration among patients with hematologic malignancies who receive hematopoietic stem-cell transplants or intensive chemotherapy.

Zygomycosis is increasingly reported as a cause of life-threatening fungal infections. A higher proportion of cases reported over the last decades have been in cancer patients, with or without hematopoietic stem cell transplantation (HSCT). The new anti-fungal agent voriconazole is a recently identified risk factor for developing zygomycosis. We reviewed the clinical characteristics and outcomes of a large cohort of cancer patients who developed zygomycosis after exposure to voriconazole. Health care professionals at 13 large cancer centers provided clinical information on cancer patients with zygomycosis and prior exposure to voriconazole. Criteria for inclusion were 5 days or more of voriconazole use and diagnostic confirmation with tissue or histology. Fifty-eight cases were identified among patients with hematologic malignancies, 62% including patients who underwent a HSCT procedure. Fifty-six patients received voriconazole for primary or secondary prophylaxis against fungal infection. In addition to prior exposure to voriconazole, patients also had several of the previously established risk factors for zygomycosis. Amphotericin B was the most commonly prescribed anti-fungal therapy. Overall mortality was 73%. We conclude that zygomycosis after exposure to voriconazole is a recently described entity that is frequently fatal, despite treatment with currently available anti-fungal agents and surgery.

Croatian Medical Journal introduces culture, control, and the study of research integrity.

Culture, control, and the study of research integrity represents the future goals of the Croatian Medical Journal. This article will highlight research integrity as experienced in the USA by the Office of Research Integrity (ORI) and discuss the framework being developed in Croatia. First, the Croatian Medical Journal seeks to promote a research culture that is aware of research integrity. This will be accomplished through the education and training of Croatian researchers interested in publishing their results in international scientific journals. To facilitate this goal, the Croatian Medical Journal introduces, what it believes to be, the first Research Integrity Editor. Second, the Croatian Medical Journal intends to facilitate the development of an Office of Research Integrity based on ORI model. The Croatian office of research integrity would be authorized to develop regulations to define scientific misconduct, investigate, and develop administrative actions against those found to have committed scientific misconduct. Furthermore, the office would be responsible for developing national education standards for promoting research integrity and the responsible conduct of research. Third, the Croatian Medical Journal is developing a science-based research agenda. This new research agenda will examine topics similar to those presented recently at the first Research Conference on Research Integrity held in Bethesda, Maryland, USA (November, 2000). The initial research topics would include studying those variables and mechanisms that help to promote research integrity and honorable research practices. This Editorial represents the first step towards achieving this goals, by establishing a collaborative relationship between ORI and the Croatian Medical Journal.

Office of Research Integrity: a reflection of disputes and misunderstandings.

Each year, the U.S. Public Health Service (PHS) provides billions of dollars to support over 30,000 extramural research grants to more than 2,000 institutions in the U.S. and other countries. The Office of Research Integrity (ORI) is responsible for protecting the integrity of the research supported by the grants awarded for the PHS extramural research program. One of its responsibilities includes monitoring investigations into alleged or suspected scientific misconduct by institutions that receive the PHS funds. However, not all of the alleged or suspected scientific misconduct meet the the PHS definition of scientific misconduct. Among the wide range of allegations that the ORI receives are those that are ultimately determined to be authorship disputes. This article will report on ORI's functions and review some of the commonly reported allegations that do not constitute scientific misconduct according to the PHS definition.

Body perceptions of bulimic and nonbulimic groups.

A brief survey measuring satisfaction with the body, concern for physical appearance, and motivations for selection of clothing was administered to 30 women in a university-sponsored support group for bulimic students and 30 women randomly selected from a college campus. No mean differences were found between the groups on concern for physical appearance when in a social setting, but mean differences were significant on satisfaction with weight, satisfaction with body image, and concern for physical appearance when alone.

Duct epithelial cells cultured from human pancreas processed for transplantation retain differentiated ductal characteristics.

A procedure is described for the isolation and growth in vitro of epithelial cells from the duct network of human pancreas, referred to as DEC. A significant advantage of our procedure over previously published procedures is that it enables the isolation of DEC from small pieces of pancreas tissue (< 5 g) and, also, from the digest remaining after the isolation of islet cells from human pancreas, material that would normally be discarded. These were the only reliable sources for pancreas tissue available to us. This procedure shows that some of the techniques that have been successfully used for the isolation of rodent DEC are also valuable in the isolation of human DEC. In particular, the use of cholera toxin to prevent fibroblast growth and contamination obviates the need for the time-consuming procedure of physically removing fibroblasts or the use of expensive fibroblast-specific monoclonal antibodies. The use of sieving to separate the digest immediately achieves a partial purification, which, coupled with that of allowing duct cysts to form, adds to the purity of the final preparation. The ductal system of the intact pancreas tissue and the DEC derived from it expressed cytokeratins 7, 8/18, and 19 and markers for the presence of MUC1, CFTR, and carbonic anhydrase II, which are specific for ductal epithelial cells or for pancreatic ductal functions. This study showed that it is possible to obtain selectively viable DEC from small ducts in otherwise waste pieces of human pancreas. It showed that these cells retained all of the epithelial characteristics that were examined and, in combination with data from an earlier study, showed that the cultured DEC retain the metabolic functions of duct epithelial cells in vivo.

Experimental evidence for the origin of ductal-type adenocarcinoma from the islets of Langerhans.

To investigate the role of the islets of Langerhans in pancreatic carcinogenesis, freshly isolated islets from male Syrian hamsters were transplanted into the right submandibular glands of 50 female hamsters that were or were not pre-treated with streptozotocin. Thyroid gland fragments, cellulose powder, and immortal hamster pancreatic ductal cells were injected into the left submandibular gland of the same hamsters. All recipient hamsters were then treated with the potent pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine weekly at a dose of 40 mg/kg of body weight for 3 weeks. Between 3 and 8 weeks later, 18 of 75 (24%) hamsters developed large ductal-type adenocarcinomas in the submandibular gland region, where islets were transplanted, but none developed tumors in the left submandibular gland. In 9 of 18 hamsters, tumors were multiple so that a total of 31 cancers were found. Eleven of these carcinomas were in the vicinity of transplanted islets, eight of which showed intra-insular ductular or cyst formation as seen in the pancreas of hamsters during pancreatic carcinogenesis. The formation of ductular structures within islets was also demonstrated in vitro. Some tumor cells in the vicinity of these islets were reactive with anti-insulin. Y chromosome message was found by polymerase chain reaction analysis in one of the three tumors examined. Also, like the induced pancreatic tumors, all three submandibular gland tumors that were examined had the mutation of the c-Ki-ras oncogene at codon 12 and all tumors expressed blood group A antigen. These and other findings strongly suggest that some components of islets, most probably stem cells, are the origin of ductal-type adenocarcinomas in this model.

Desensitization of the adipocyte A(1) adenosine receptor during untreated experimental diabetes mellitus.

We examined the changes that occur in the adenosine receptor system during diabetes mellitus. Experimental diabetes mellitus was induced in male Lewis rats with streptozocin (65 mg/kg), and A(1) adenosine receptor binding was characterized with [(125)I]N (6)-2-(4-aminophenyl) ethyladenosine. In adipocytes, high-affinity A(1) adenosine receptor binding decreased from 1466±228 of protein to 312±123 fmol/mg of protein (p<0.01) following 14 d of untreated diabetes mellitus. Neither the dissociation constant (K (d)=1.3±0.2 nM) nor the basal level of adenylate cyclase activity (2.8±1.1 pmol cAMP/mg of protein/min) was altered by diabetes mellitus. The dose-response curve for the inhibition of adenylate cyclase byN (6)-R-phenylisopropyladenosine (R-PIA), however, did show a rightward shift, indicating that diabetic adipocyte membranes were less sensitive to the effects of adenosine than nondiabetic adipocyte membranes. In contrast, the A(1) adenosine receptor-binding characteristics and adenylate cyclase dose-response curve for cerebral cortical tissue were unchanged by diabetes. These findings suggest that diabetes has tissue-specific effects on the A(1) adenosine receptor system. Furthermore, the decreased sensitivity to adenosine potentially worsens the hyperlipidemia associated with diabetes mellitus. Such alterations in the adenosine receptor system may play a previously undescribed role in the pathophysiology of diabetes mellitus and may help explain why some organs are severely affected by diabetes, but others are relatively spared. Understanding these alterations in adenosine receptor function may lead tonovel therapies of this common metabolic disease.

Characteristics of human synovial fibroblast activation by IL-1 beta and TNF alpha.

Human synovial fibroblast cell lines (HSN), established from tissues obtained from the knee joints of arthritis patients undergoing arthoplasty, were used to investigate the effects of human interleukin-1 (IL-1) beta and tumour necrosis factor (TNF)alpha on proliferation and prostaglandin E2 (PGE2) secretion. IL-1 beta and TNF alpha were equipotent stimulators of HSN proliferation. Classical non-steroidal anti-inflammatory drugs and glucocorticoids significantly augmented this effect. In addition, IL-1 beta and TNF alpha were potent inducers of PGE2 production while exogenous PGE2 was growth inhibiting. These data suggest that the secretion of PGE2 by monokine-stimulated HSN exerts a negative feedback signal. Further examination of IL-1 beta- and TNF alpha-induced PGE2 secretion revealed IL-1 beta to be a more potent stimulator; however, this observation may be due, in part, to differences in the kinetics of induction. Rabbit anti-IL-1 beta and anti-TNF alpha specifically neutralized both proliferation and PGE2 production induced by these monokines, but anti-IL-1 beta (or anti-IL-1 alpha) did not block TNF alpha activity. It is unclear whether TNF alpha stimulates HSN to produce IL-1, but the antibody data suggest that extracellular IL-1 is not responsible for TNF alpha in vitro activity.

7C3, a marker for the differentiation of human macrophage cell lines.

The induction of differentiation in the human monoblastlike cell line U937 by 1,25 dihydroxyvitamin D3, interferon gamma, or phorbol esters is associated with the expression of a novel surface antigen, 7C3. The expression of 7C3 is maximal after 24 hr and is dependent upon de novo protein synthesis. The appearance of 7C3 during U937 differentiation is inhibited by dexamethasone while the increased expression of the macrophage marker OKM1 is not affected. 7C3 antigen is also expressed on HL60 cells when induced along the macrophage pathway and is expressed weakly on peripheral blood monocytes but not on lymphoid cells or granulocytes. 7C3 expression is sensitive to trypsin and low concentrations of the nonionic detergents NP-40 and Triton X-100. The induction of 7C3 expression may serve as a useful model to understand the regulatory events involved during the early phases of monocyte-macrophage differentiation.

In vivo expression and regulation of murine IL 2 receptors after antigen sensitization.

We have studied the in vivo regulation and expression of the murine IL 2 receptor after antigen sensitization. High and low affinity receptor expression has been studied by flow cytometry analysis and radiolabeled IL 2 binding. Both anti-IL 2 receptor antibody and unlabeled IL 2 inhibited the radiolabeled IL 2 binding. The kinetics of expression of the IL 2 receptor closely correspond to the proliferative response, as assessed by IUdR radioisotope uptake. The expression of IL 2 receptors correlated with the proliferative response profile of the murine strains surveyed during a study of responses to picryl chloride. Neither immune compromised 4-mo-old MRL/lpr mice nor athymic nude mice generated significant antigen-specific proliferative responses or IL 2 receptor expression after antigen sensitization. Mice rendered specifically unresponsive to antigen displayed reduced proliferative responses to the tolerizing antigen, as well as reduced numbers of IL 2 receptor-positive cells. Finally, the treatment of mice with immunosuppressive drugs reduced both the proliferative responses as well as the number of IL 2 receptor-positive cells. However, at the cellular level, the drugs produced different effects on IL 2 receptor expression.

Characterization and specificity of a high titre polyclonal goat anti-murine IL-1 antibody.

The immunization of goats with an HPLC-purified IL-1 preparation derived from the supernatants of LPS-induced P388D1 cultures has resulted in the derivation of a high titre antiserum specific for murine IL-1. This antiserum exhibits a 50% inhibition of an IL-1-dependent thymocyte costimulation assay at a reciprocal dilution of 30,000 and antibody activity is still detected at 100,000-fold dilution. The goat anti-murine IL-1 serum is specific for murine IL-1 synthesized by several murine macrophage cell lines and does not neutralize human, rabbit or porcine (catabolin) IL-1. The antiserum also inhibits antigen-induced proliferation of the D10.G4 helper T-cell line. In addition to the reaction against IL-1, the antiserum also detects three additional peptides with molecular weights between 20,000 and 30,000.

Effect of myeloma IgE injections on passive and active cutaneous anaphylaxis in rats.

The ability of injected rat IgE myeloma protein IR162 to inhibit passive and active cutaneous anaphylaxis in Lewis rats was investigated. IgE injected i.p. 24 hr before the sensitization with IgE anti-ovalbumin (OVA) completely inhibited both IgE- and IgG2a-induced passive cutaneous anaphylactic (PCA) reactions at a dose (2.5 mg/100 g body weight) that resulted in peak serum concentrations of 150 micrograms IgE IR162/ml. Peak IgE IR162 serum concentrations of 20 to 60 micrograms/ml inhibited the PCA reaction in approximately 50% of the rats. Intracutaneous injection of a mixture of myeloma IgE and anti-OVA IgE in a ratio of 100:1 or more also inhibited the PCA reaction. In contrast, the PCA reaction was not inhibited by seven daily doses of IgE beginning 24 hr after passive sensitization. Likewise, the cutaneous anaphylactic reaction elicited in rats 14 days after immunization with OVA and Bordetella pertussis was not prevented by daily injections of myeloma IgE despite a 1000- to 3000-fold excess of the myeloma IgE to anti-OVA IgE serum concentration. The data demonstrate that parenteral administration of myeloma IgE inhibits the PCA reaction only when given before passive sensitization and does not prevent cutaneous anaphylaxis in actively immunized rats. Because myeloma IgE failed to inhibit anaphylactic reactions in actively immunized rats, it is questionable whether administering human IgE-derived synthetic peptides or recombinant DNA-produced IgE fragments will be able to prevent allergic diseases by blocking the IgE Fc receptors on mast cells.