Antiendotoxin activity of protegrin analog IB-367 alone or in combination with piperacillin in different animal models of septic shock

The therapeutic efficacy of protegrin peptide IB-367 was investigated in three rat models of septic shock: (i) rats injected intraperitoneally with 1mg Escherichia coli 0111:B4 lipopolysaccharide, (ii) rats given an intraperitoneal injection of 2 X 10(10) CFU of E. coli ATCC 25922, and (iii) rats in which intra-abdominal sepsis was induced via cecal ligation and puncture. All animals were randomized to receive parenterally isotonic sodium chloride solution, 1mg/kg of IB-367, 60mg/kg piperacillin and 1mg/kg of IB-367 plus 60mg/kg piperacillin. The peptide demonstrated lower level of antimicrobial activity than piperacillin, nevertheless it exhibited the dual properties of antimicrobial and antiendotoxin agent. Finally IB-367 and piperacillin association showed to be the most effective therapeutic approach.     

Sply regulation of sphingolipid signaling molecules is essential for Drosophila development

Sphingosine-1-phosphate is a sphingolipid metabolite that regulates cell proliferation, migration and apoptosis through specific signaling pathways. Sphingosine-1-phosphate lyase catalyzes the conversion of sphingosine-1-phosphate to ethanolamine phosphate and a fatty aldehyde. We report the cloning of the Drosophila sphingosine-1-phosphate lyase gene (Sply) and demonstrate its importance for adult muscle development and integrity, reproduction and larval viability. Sply expression is temporally regulated, with onset of expression during mid-embryogenesis. Sply null mutants accumulate both phosphorylated and unphosphorylated sphingoid bases and exhibit semi-lethality, increased apoptosis in developing embryos, diminished egg-laying, and gross pattern abnormalities in dorsal longitudinal flight muscles. These defects are corrected by restoring Sply expression or by introduction of a suppressor mutation that diminishes sphingolipid synthesis and accumulation of sphingolipid intermediates. This is the first demonstration of novel and complex developmental pathologies directly linked to a disruption of sphingolipid catabolism in metazoans.     

Transglutaminase-mediated fibronectin multimerization in lung endothelial matrix in response to TNF-alpha

Exposure of lung endothelial monolayers to tumor necrosis factor (TNF)-alpha causes a rearrangement of the fibrillar fibronectin (FN) extracellular matrix and an increase in protein permeability. Using calf pulmonary artery endothelial cell layers, we determined whether these changes were mediated by FN multimerization due to enhanced transglutaminase activity after TNF-alpha (200 U/ml) for 18 h. Western blot analysis indicated that TNF-alpha decreased the amount of monomeric FN detected under reducing conditions. Analysis of (125)I-FN incorporation into the extracellular matrix confirmed a twofold increase in high molecular mass (HMW) FN multimers stable under reducing conditions (P < 0.05). Enhanced formation of such HMW FN multimers was associated with increased cell surface transglutaminase activity (P < 0.05). Calf pulmonary artery endothelial cells pretreated with TNF-alpha also formed nonreducible HMW multimers of FN when layered on surfaces precoated with FN. Inhibitors of transglutaminase blocked the TNF-alpha-induced formation of nonreducible HMW multimers of FN but did not prevent either disruption of the FN matrix or the increase in monolayer permeability. Thus increased cell surface transglutaminase after TNF-alpha exposure initiates the enhanced formation of nonreducible HMW FN multimers but did not cause either the disruption of the FN matrix or the increase in endothelial monolayer permeability.     

Application of one-step liquid chromatography–electrospray tandem MS/MS and collision-induced dissociation to quantification of ezetimibe and identification of its glucuronated metabolite in human serum: A pharmacokinetic study

A new one-step liquid chromatography–electrospray tandem MS/MS method is described to quantify ezetimibe (EZM) a novel lipid lowering drug in human serum. Also using collision-induced dissociation (CID) of the analyte, identification and chromatographic separation of its major metabolite, ezetimibe glucuronide (EZM-G) is achieved in this study. A thawed serum aliquot of 100 μL was deproteinated by addition of 500 μL methanol containing omeprazole as internal standard (I.S.). Separation of the drug, its metabolite and the I.S. were achieved using acetonitrile–water (70:30, v/v) as mobile phase at flow rate of 0.5 mL/min on a MZ PerfectSil target C18 column. Multiple reaction monitoring (MRM) mode of precursor–product ion transition (408.7 → 272.0 for EZM and 345 → 194.5 for the I.S.) was applied for detection and quantification of the drug while, EZM-G was chromatographically separated and identified using CID. The analytical method was linear over the concentration range of 1–32 ng/mL of EZM in human serum with a limit of quantification of 1 ng/mL. The coefficient variation values of both inter- and intra-day analysis were less than 8% whereas the percentage error was less than 3.7. The validated method was applied in a randomized cross-over bioequivalence study of two different EZM preparations in 24 healthy volunteers.     

Development of Sustained Release Capsules Containing “Coated Matrix Granules of Metoprolol Tartrate”

The objective of this investigation was to prepare sustained release capsule containing coated matrix granules of metoprolol tartrate and to study its in vitro release and in vivo absorption. The design of dosage form was performed by choosing hydrophilic hydroxypropyl methyl cellulose (HPMC K100M) and hydrophobic ethyl cellulose (EC) polymers as matrix builders and Eudragit® RL/RS as coating polymers. Granules were prepared by composing drug with HPMC K100M, EC, dicalcium phosphate by wet granulation method with subsequent coating. Optimized formulation of metoprolol tartrate was formed by using 30% HPMC K100M, 20% EC, and ratio of Eudragit® RS/RL as 97.5:2.5 at 25% coating level. Capsules were filled with free flowing optimized granules of uniform drug content. This extended the release period upto 12 h in vitro study. Similarity factor and mean dissolution time were also reported to compare various dissolution profiles. The network formed by HPMC and EC had been coupled satisfactorily with the controlled resistance offered by Eudragit® RS. The release mechanism of capsules followed Korsemeyer–Peppas model that indicated significant contribution of erosion effect of hydrophilic polymer. Biopharmaceutical study of this optimized dosage form in rabbit model showed 10 h prolonged drug release in vivo. A close correlation (R² = 0.9434) was established between the in vitro release and the in vivo absorption of drug. The results suggested that wet granulation with subsequent coating by fluidized bed technique, is a suitable method to formulate sustained release capsules of metoprolol tartrate and it can perform therapeutically better than conventional immediate release dosage form.Key words: biopharmaceutical evaluation, coated granules, metoprolol tartrate, sustained release     

Localization of synaptic proteins involved in neurosecretion in different membrane microdomains

A number of proteins and signalling molecules modulate voltage-gated calcium channel activity and neurosecretion. As recent findings have indicated the presence of Ca(v)2.1 (P/Q-type) channels and soluble N-ethyl-maleimide-sensitive fusion protein attachment protein receptors (SNAREs) in the cholesterol-enriched microdomains of neuroendocrine and neuronal cells, we investigated whether molecules known to modulate neurosecretion, such as the heterotrimeric G proteins and neuronal calcium sensor-1 (NCS-1), are also localized in these microdomains. After immuno-isolation, flotation gradients from Triton X-100-treated synaptosomal membranes revealed the presence of different detergent-resistant membranes (DRMs) containing proteins of the exocytic machinery (Ca(v)2.1 channels and SNAREs) or NCS-1; both DRM subtypes contained aliquots of heterotrimeric G protein subunits and phosphatidylinositol-4,5-bisphosphate. In line with the biochemical data, confocal imaging of immunolabelled membrane sheets revealed the localization of SNARE proteins and NCS-1 in different dot-like structures. This distribution was largely impaired by treatment with methyl-beta-cyclodextrin, thus suggesting the localization of all three proteins in cholesterol-dependent domains. Finally, bradykinin (which is known to activate the NCS-1 pathway) caused a significant increase in NCS-1 in the DRMs. These findings suggest that different membrane microdomains are involved in the spatial organization of the complex molecular network that converges on calcium channels and the secretory machinery.     

Neuroendocrine immunity in patients with Alzheimer's disease: toward translational epigenetics

The emerging domain of epigenetics in molecular medicine finds application for a variety of patient populations. Here, we present fundamental neuroendocrine immune evidence obtained in patients with senile dementia of the Alzheimer's type (sDAT), and discuss the implications of these data from the viewpoint of translational epigenetics of Alzheimer's disease. We followed 18 subjects with mild sDAT treated with acetylcholinesterase inhibitors, and 10 control subjects matched for age in a repeated measure design every six months for 18 months. We monitored psychosocial profile (Mini-Mental State Examination, Functional Assessment Staging, Independence in Activities of Daily Living, Depression, Profile of Moods States) in parallel to immunophenotypic parameters of T cell subpopulations by flow cytometry. Based on change in the mini-mental state score at entry and at 18 months, patients with sDAT were assigned to a "fast progression" (delta greater than 2 points) or to a "slow progression" group (delta less than or equal to 2 points). The change in circulating activated T cells (CD3+Dr+) with time in patients with sDAT was significantly inversely correlated with the change in time in natural killer (NK) cytotoxic activity to cortisol modulation in these patients, which was greater in patients with fast progression, compared to slow progression sDAT. These data indicate underlying neuroendocrine immune processes during progression of sDAT. Our observations suggest that psychoimmune measures such as those we have monitored in this study provide relevant information about the evolving physiological modulation in patients with sDAT during progression of Alzheimer's disease, and point to new or improved translational epigenetic treatment interventions.     

Physiologic modulation of natural killer cell activity as an index of Alzheimer's disease progression

Patients with Alzheimer's disease (AD) are characterized by an altered sensitivity to cortisol-mediated modulation of circulating lymphocytes. Longitudinal studies are needed to address the clinical applicability of these abnormalities as prognostic factors. Therefore, we designed a longitudinal study to address the clinical applicability of physiologic modulation of Natural Killer (NK) cell activity as a prognostic factor in AD. NK activity was assessed as baseline measurement and in response to modulation by cortisol at 10(-6)M. To verify the immunophysiological integrity of the NK cell population, we tested augmentation of NK cytotoxicity by human recombinant interleukin (IL)-2 (100 IU/ml) as control. The response to modulation by cortisol or by IL-2 was significantly greater in patients with AD. Based on change in the Mini-Mental State score at entry and at 18 months, patients with AD could be assigned to a "fast progression" (Delta > 2 points) or to a "slow progression" group (Delta 相似文献   

Predictors of mortality amongst recipients of implantable cardioverter defibrillators for secondary prevention of cardiac arrest

Background

Implantable Cardioverter-defibrillators (ICD) reduce mortality in survivors of cardiac arrest (CA). We investigated the predictors of mortality after ICD implantation in survivors of CA.

Methods

Retrospective review of clinical records and social security death index of all patients who received an ICD in a preexisting database of survivors of CA at the University of Pittsburgh Medical Center was performed. Multivariate analyses using the Cox proportional hazard model were performed with backward elimination to identify independent predictors of the time to death, and Kaplan-Meier curves were plotted.

Results

Eighty patients (64 men) with a mean age of 64.4±12.5 years were followed for 4.7±2.3 years after ICD implantation. Survival rates were 93.8%, 65% and 50% at 1, 5, and 10 years, respectively. Independent predictors of time to death were determined to include age (hazard ratio (HR) = 1.91 per 10-year increase, p = 0.003), serum creatinine ≥ 1.3 mg/dL (HR = 2.56, p = 0.004), and QRS width >120 ms (HR = 5.14, p = 0.012).

Conclusions

In this sample of ICD recipients secondary to CA, older age, elevated serum creatinine, and wider QRS duration were independent predictors of mortality. The presence of more than one risk factor in the same patient was associated with higher mortality rates. Whether interventions such as biventricular pacing can offset this increase risk of death warrants further investigation.