IVIVC in oral absorption for fenofibrate immediate release tablets using a dissolution/permeation system

The usefulness of a dissolution/permeation (D/P) system to predict the in vivo performance of solid dosage forms containing the poorly soluble drug, fenofibrate, was studied. Biorelevant dissolution media simulating the fasted and fed state conditions of the human gastrointestinal tract were used in order to simulate the effect of food on the absorption of fenofibrate. Moreover, the results obtained from the D/P system were correlated with pharmacokinetic parameters obtained following in vivo studies in rats. The in vitro parameter (amount permeated in the D/P system) reflected well the in vivo performance in rats in terms of AUC and C(max) of fenofibric acid. This study thus demonstrates the potential of the D/P system as valuable tool for absorption screening of dosage forms for poorly soluble drugs.     

Granulocyte colony-stimulating factor impairs liver regeneration in mice through the up-regulation of interleukin-1beta

BACKGROUND/AIMS: Stem cell induction via granulocyte colony-stimulating factor (G-CSF) administration is utilized in the treatment of various diseases. Therefore, we examined the effect of G-CSF administration to a liver fibrosis model induced by dimethylnitrosamine (DMN). METHODS: ICR mice were subcutaneously injected with either G-CSF (150microg/kg) or saline at days 0, 3, 7 and 10. Subacute liver injury was established by intraperitoneal injection of DMN (10mg/kg) on three consecutive days of each week. RESULTS: G-CSF administration significantly decreased the survival rate of mice treated with DMN. There was no difference in the degree of liver injury or fibrosis between either group of mice. However, assessment by proliferating cell nuclear antigen (PCNA) revealed that the G-CSF-treated mice experienced a greater degree of inhibition of liver cell proliferation than the control mice. Interleukin-1beta (IL-1beta) mRNA expression increased in the livers of G-CSF-treated mice. PCNA staining and analysis of cell cycle-related proteins also revealed that passive immunization with anti-IL-1beta-neutralizing antibody improved the impaired hepatocellular regeneration and resulted in an improved survival rate of mice treated with G-CSF and DMN. CONCLUSIONS: G-CSF administration suppressed liver cell proliferation through the up-regulation of IL-1beta expression in DMN-induced liver injury.     

The phosphatidylethanolamine N-methyltransferase gene V175M single nucleotide polymorphism confers the susceptibility to NASH in Japanese population

BACKGROUND/AIMS: The genetic predisposition on the development of nonalcoholic steatohepatitis (NASH) has been poorly understood. A functional polymorphism Val175Met was reported in phosphatidylethanolamine N-methyltransferase (PEMT) that catalyzes the conversion of phosphatidylethanolamine to phosphatidylcholine. The aim of this study was to investigate whether the carriers of Val175Met variant impaired in PEMT activity are more susceptible to NASH. METHODS: Blood samples of 107 patients with biopsy-proven NASH and of 150 healthy volunteers were analyzed by the polymerase chain reaction (PCR) and restriction fragment length polymorphism. RESULTS: Val175Met variant allele of the PEMT gene was significantly more frequent in NASH patients than in healthy volunteers (p<0.001), and carriers of Val175Met variant were significantly more frequent in NASH patients than in healthy volunteers (p<0.01). Among NASH patients, body mass index was significantly lower (p<0.05), and non-obese patients were significantly more frequent (p<0.001) in carriers of Val175Met variant than in homozygotes of wild type PEMT. CONCLUSIONS: Val175Met variant of PEMT could be a candidate molecule that determines the susceptibility to NASH, because it is more frequently observed in NASH patients and non-obese persons with Val175Met variant of PEMT are facilitated to develop NASH.     

Selective hepatic vascular exclusion for the hepatic resection of HCC

BACKGROUND/AIMS: Selective hepatic vascular exclusion (SHVE) is an effective technique for the control of bleeding in major hepatic resections. Outcomes of the procedures of the SHVE group were compared with the non-SHVE group. METHODOLOGY: A retrospective study was carried out of 312 hepatic resections performed over a period of 10 years. The cases in this study were limited to Child's classification A, because of the rate of Child A in the SHVE group (n=82) was significantly higher than that within the non-SHVE group (n=158) (93% vs. 71%; p < 0.001). Preoperative factors, like age, gender, tumor size, intraoperative blood loss, operation time, and the postoperative course of the two groups were compared for both groups. RESULTS: The SHVE group showed significantly less blood loss, necessary blood transfusion, and a significant rate of severe postoperative complications. The rate of segmentectomy and subsegmentectomy in the SHVE group was higher than in the non-SHVE group, and the rate of partial hepatectomy and lobectomy in the non-SHVE group was higher than that in the SHVE group. Although the more difficult operations were performed in the SHVE group than in the non-SHVE group, there was no significant difference in the postoperative hospital stays in both groups. CONCLUSIONS: The SHVE technique is effective for bleeding control in major liver resections.     

Phase II study of 2-week TS-1 administration followed by 1-week rest for gastric cancer

BACKGROUND/AIMS: TS-1 monotherapy with 4-week administration followed by 2-week rest is used as the community standard treatment for metastatic gastric cancer in Japan. However, according to a postmarketing survey, the percentage of patients who received three or more courses was only 44.6%; for the reasons of discontinuation due to exacerbation of symptoms or adverse reactions during the first or second course. Therefore, we conducted the phase II study of 2-weeks administration with TS-1 followed by a 1-week rest against metastatic gastric cancer, aiming for mitigation of adverse reactions without reduction of antitumor effect. METHODOLOGY: Thirty-five patients were enrolled between 2001 and 2003 at nine institutes in Japan. One cycle of TS-1 treatment whose dosage was 80 mg/m2/day consisted of administration for 2 weeks followed by a 1-week rest. The primary endpoint was overall response rate and the secondary endpoints were safety and feasibility. RESULTS: There were 6 PRs, 13 NCs, 11 PDs, and 5 patients were not evaluable (NE), yielding a response rate of 17%. The median survival time of all patients was 290 days. Severe adverse Grade 3 or 4 reactions were observed in 8 (23%) patients. The rate of patients who received six or more courses was 43%. The cumulative rate of the relative total administration days was 93%. CONCLUSIONS: We concluded that the schedule of TS-1 administration for 2 weeks followed by a 1-week rest might not be superior to the conventional schedule (4 weeks on and 2 weeks off) with regard to the antitumor effect, adverse reactions and prolonged medication, although it was acceptable from the point of view of survival.     

Apoptosis signal-regulating kinase-1 is involved in vascular endothelial and cardiac remodeling caused by nitric oxide deficiency

Long-term treatment with N(omega)-nitro-l-arginine methylester (l-NAME), an NO synthase inhibitor, induces hypertension and cardiovascular injury. However, its precise mechanism is unknown. Using apoptosis signal-regulating kinase-1 (ASK1)-deficient mice, we investigated the role of ASK1 in cardiovascular injury caused by l-NAME treatment. l-NAME was orally administered to ASK1-deficient and C57BL/6J (wild) mice for 8 weeks. l-NAME treatment increased blood pressure of wild and ASK1-deficient mice to a similar extent, indicating no role of ASK1 in NO-deficient hypertension. l-NAME treatment significantly impaired acetylcholine-induced carotid arterial relaxation in wild mice (P<0.01), being associated with the decreased endothelial NO synthase (eNOS) activity (P<0.01) and the increased disruption of eNOS dimer (P<0.01), whereas these changes by l-NAME were substantially attenuated in ASK1-deficient mice. Thus, ASK1 is involved in the impairment of vascular endothelial function by reducing eNOS activity and disrupting eNOS dimer. l-NAME treatment increased vascular reduced nicotinamide-adenine dinucleotide phosphate oxidase activity and superoxide in wild mice to a greater extent than in ASK1 deficient mice. l-NAME treatment in wild mice caused cardiac hypertrophy, myocyte apoptosis, macrophage infiltration, coronary arterial remodeling, interstitial fibrosis, and the expression of monocyte chemoattractant protein-1 and transforming growth factor-beta1, whereas these cardiac changes by l-NAME were absent in ASK1-deficient mice. Cardiac reduced nicotinamide-adenine dinucleotide phosphate oxidase activation and superoxide elevation by l-NAME were much less in ASK1-deficient mice than in wild mice. Our work provided the first evidence that ASK1 is implicated in vascular endothelial dysfunction and cardiovascular remodeling induced by NO deficiency by regulating eNOS and reduced nicotinamide-adenine dinucleotide phosphate oxidase.     

An inducible lambdoid prophage encoding cytolethal distending toxin (Cdt-I) and a type III effector protein in enteropathogenic Escherichia coli

Cytolethal distending toxins (CDTs) are inhibitory cyclomodulins, which block eukaryotic cell proliferation and are produced by a diverse group of Gram-negative bacteria, including Escherichia coli strains associated with intestinal and extraintestinal infections. However, the mode of transmission of the toxin gene clusters among diverse bacterial pathogens is unclear. We found that Cdt-I produced by enteropathogenic E. coli strains associated with diarrhea is encoded by a lambdoid prophage, which is inducible and infectious. The genome of Cdt-I converting phage (CDT-1Phi) comprises 47,021 nucleotides with 60 predicted ORFs organized into six genomic regions encoding the head and tail, virulence, integrase, unknown functions, regulation, and lysis. The genomic organization of CDT-1Phi is similar to those of SfV, a serotype-converting phage of Shigella flexneri, and UTI89, a prophage identified in uropathogenic E. coli. Besides the cdtI gene cluster, the virulence region of CDT-1Phi genome contains sequences homologous to a truncated cycle inhibiting factor and a type 3 effector protein. Mutation analysis of susceptible E. coli strain C600 suggested that the outer membrane protein OmpC is a putative receptor for CDT-1Phi. CDT-1Phi genome was also found to integrate into the host bacterial chromosome forming lysogens, which produced biologically active Cdt-I. Furthermore, phage induction appeared to cause enhanced toxigenicity of the E. coli strains carrying lysogenic CDT-1Phi. Our results suggest that CDT-1Phi is the latest member of a growing family of lambdoid phages encoding bacterial cyclomodulins and that the phage may have a role in horizontal transfer of these virulence genes.