Bioequivalence study of two brands of phenytoin sodium 100mg formulations in healthy adult male rabbits

The objective of the study was to compare the bioavailability of a single oral 100 mg dose of two brands of phenytoin sodium formulations available in the Nepalese market. Formulation B was taken as test drug and compared with the innovator brand which was taken as reference standard. A randomized, two-way crossover study was done in six healthy adult male rabbits. All six rabbits received a single oral 100 mg dose of both the formulations with a two-week washout period between the formulations. Blood samples for plasma phenytoin levels were collected at 0.25, 1, 2, 4, 6, 8, 10, 12, 16, 24 hours. The pharmacokinetic parameters of the two brands of phenytoin sodium calculated were area under the concentration versus time curve from time zero to 24 hours (AUC 0-24), Area under the Curve from time zero to infinity (AUC(0-infinity)), peak plasma concentration (C-max) and time of peak concentration (t(max)). Formulation B failed to comply in terms of Area under the Curve (AUC), an important pharmacokinetic parameter to test bioequivalency, which was tested at significance level 0.05. This showed that the test formulation is not bioequivalent with the innovator. Taken together, our preliminary findings suggest that further studies in a large population is needed before switching phenytoin brands once a patient is carefully titrated to a given phenytoin brand

Western diet‐induced increase in colonic bile acids compromises epithelial barrier in nonalcoholic steatohepatitis

There is compelling evidence implicating intestinal permeability in the pathogenesis of nonalcoholic steatohepatitis (NASH), but the underlying mechanisms remain poorly understood. Here we examined the role of bile acids (BA) in western diet (WD)‐induced loss of colonic epithelial barrier (CEB) function in mice with a genetic impairment in intestinal epithelial barrier function, junctional adhesion molecule A knockout mice, F11r−/−. WD‐fed knockout mice developed severe NASH, which was associated with increased BA concentration in the cecum and loss of CEB function. Analysis of cecal BA composition revealed selective increases in primary unconjugated BAs in the WD‐fed mice, which correlated with increased abundance of microbial taxa linked to BA metabolism. In vitro permeability assays revealed that chenodeoxycholic acid (CDCA), which was elevated in the cecum of WD‐fed mice, increased paracellular permeability, while the BA‐binding resin sevelamer hydrochloride protected against CDCA‐induced loss of barrier function. Sequestration of intestinal BAs by in vivo delivery of sevelamer to WD‐fed knockout mice attenuated colonic mucosal inflammation and improved CEB. Sevelamer also reduced hepatic inflammation and fibrosis, and improved metabolic derangements associated with NASH. Collectively, these findings highlight a hitherto unappreciated role for BAs in WD‐induced impairment of the intestinal epithelial barrier in NASH.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155502/1/fsb220488.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155502/2/fsb220488_am.pd

Prostate cancer cell malignancy via modulation of HIF-1 alpha pathway with isoflurane and propofol alone and in combination

BACKGROUND: Surgery is considered to be the first line treatment for solid tumours. Recently, retrospective studies reported that general anaesthesia was associated with worse long-term cancer-free survival when compared with regional anaesthesia. This has important clinical implications; however, the mechanisms underlying those observations remain unclear. We aim to investigate the effect of anaesthetics isoflurane and propofol on prostate cancer malignancy. METHODS: Prostate cancer (PC3) cell line was exposed to commonly used anaesthetic isoflurane and propofol. Malignant potential was assessed through evaluation of expression level of hypoxia-inducible factor-1α (HIF-1α) and its downstream effectors, cell proliferation and migration as well as development of chemoresistance. RESULTS: We demonstrated that isoflurane, at a clinically relevant concentration induced upregulation of HIF-1α and its downstream effectors in PC3 cell line. Consequently, cancer cell characteristics associated with malignancy were enhanced, with an increase of proliferation and migration, as well as development of chemoresistance. Inhibition of HIF-1α neosynthesis through upper pathway blocking by a PI-3K-Akt inhibitor or HIF-1α siRNA abolished isoflurane-induced effects. In contrast, the intravenous anaesthetic propofol inhibited HIF-1α activation induced by hypoxia or CoCl(2). Propofol also prevented isoflurane-induced HIF-1α activation, and partially reduced cancer cell malignant activities. CONCLUSIONS: Our findings suggest that modulation of HIF-1α activity by anaesthetics may affect cancer recurrence following surgery. If our data were to be extrapolated to the clinical setting, isoflurane but not propofol should be avoided for use in cancer surgery. Further work involving in vivo models and clinical trials is urgently needed to determine the optimal anaesthetic regimen for cancer patients

Blocking integrin α4β7-mediated CD4 T cell recruitment to the intestine and liver protects mice from western diet-induced non-alcoholic steatohepatitis

Background & aimsThe heterodimeric integrin receptor α4β7 regulates CD4 T cell recruitment to inflamed tissues, but its role in the pathogenesis of non-alcoholic steatohepatitis (NASH) is unknown. Herein, we examined the role of α4β7-mediated recruitment of CD4 T cells to the intestine and liver in NASH.MethodsMale littermate F11r+/+ (control) and junctional adhesion molecule A knockout F11r-/- mice were fed a normal diet or a western diet (WD) for 8 weeks. Liver and intestinal tissues were analyzed by histology, quantitative reverse transcription PCR (qRT-PCR), 16s rRNA sequencing and flow cytometry. Colonic mucosa-associated microbiota were analyzed using 16s rRNA sequencing. Liver biopsies from patients with NASH were analyzed by confocal imaging and qRT-PCR.ResultsWD-fed knockout mice developed NASH and had increased hepatic and intestinal α4β7+ CD4 T cells relative to control mice who developed mild hepatic steatosis. The increase in α4β7+ CD4 T cells was associated with markedly higher expression of the α4β7 ligand mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the colonic mucosa and livers of WD-fed knockout mice. Elevated MAdCAM-1 expression correlated with increased mucosa-associated Proteobacteria in the WD-fed knockout mice. Antibiotics reduced MAdCAM-1 expression indicating that the diet-altered microbiota promoted colonic and hepatic MAdCAM-1 expression. α4β7 blockade in WD-fed knockout mice significantly decreased α4β7+ CD4 T cell recruitment to the intestine and liver, attenuated hepatic inflammation and fibrosis, and improved metabolic indices. MAdCAM-1 blockade also reduced hepatic inflammation and fibrosis in WD-fed knockout mice. Hepatic MAdCAM-1 expression was elevated in patients with NASH and correlated with higher expression of α4 and β7 integrins.ConclusionsThese findings establish α4β7/MAdCAM-1 as a critical axis regulating NASH development through colonic and hepatic CD4 T cell recruitment.Lay summaryNon-alcoholic steatohepatitis (NASH) is an advanced and progressive form of non-alcoholic fatty liver disease (NAFLD), and despite its growing incidence no therapies currently exist to halt NAFLD progression. Herein, we show that blocking integrin receptor α4β7-mediated recruitment of CD4 T cells to the intestine and liver not only attenuates hepatic inflammation and fibrosis, but also improves metabolic derangements associated with NASH. These findings provide evidence for the potential therapeutic application of α4β7 antibody in the treatment of human NASH