Hydrogen sulfide (H2S) is a novel gaseous mediator produced by cystathionine-beta-synthase and cystathionine-gamma-lyase in the cardiovascular system, including the heart. Using a rat model of regional myocardial ischemia/reperfusion, we investigated the effects of an H2S donor (sodium hydrogen sulfide [NaHS]) on the infarct size and apoptosis caused by ischemia (25 min) and reperfusion (2 h). Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by NaHS. Specifically, we demonstrate that NaHS (1) attenuates the increase in caspase 9 activity observed in cardiac myocytes isolated from the area at risk (AAR) of hearts subjected in vivo to regional myocardial I/R and (2) ameliorates the decrease in expression of Bcl-2 within the AAR obtained from rat hearts subjected to regional myocardial I/R. The cardioprotective effects of NaHS were abolished by 5-hydroxydeconoate, a putative mitochondrial adenosine triphosphate-sensitive potassium channel blocker. Furthermore, NaHS attenuated the increase in the I/R-induced (1) phosphorylation of p38 mitogen-activated protein kinase and Jun N-terminal kinase, (2) translocation from the cytosol to the nucleus of the p65 subunit of nuclear factor-kappaB, (3) intercellular adhesion molecule 1 expression, (4) polymorphonuclear leukocyte accumulation, (5) myeloperoxidase activity, (6) malondialdehyde levels, and (7) nitrotyrosine staining determined in the AAR obtained from rat hearts subjected to regional myocardial I/R. In conclusion, we demonstrate that the cardioprotective effect of NaHS is secondary to a combination of antiapoptotic and anti-inflammatory effects. The antiapoptotic effect of NaHS may be in part due to the opening of the putative mitochondrial adenosine triphosphate-sensitive potassium channels.
Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, Canadian Institutes of Health Research Strategy for Patient Oriented Research through the Ontario SPOR Support Unit, the Ontario Ministry of Health and Long-Term Care, pharmaceutical companies (with major contributions from AstraZeneca [Canada], Sanofi Aventis [France and Canada], Boehringer Ingelheim [Germany amd Canada], Servier, and GlaxoSmithKline), Novartis and King Pharma, and national or local organisations in participating countries.
Median survival time was 24 months (range, 2-60 months) among the nine patients who died, whereas median follow-up time in the remaining 19 patients is 33.4 months (range, 4.7-73 months). A trend toward a reduction in MUC4 antigen expression in high-grade tumors (55% expression) compared with low-grade (91% expression) and intermediate-grade (100% expression) tumors is identified (chi square, p =.0975). Patients with tumors expressing MUC4 antigens are at reduced risk of death (hazard ratio [HR], 0.20; p =.0531). Adjustment for pathologic grade, T stage, and age results in a much higher risk of death for patients whose tumors do not express MUC4 antigens, although this does not meet statistical significance (HR, 26.6; p =.1). Analysis of recurrence adjusting for T stage reveals that patients whose tumors do not express MUC4 antigens are at increased risk of recurrence compared with patients whose tumor expresses MUC4 antigens (HR, 6.37; p =.03). ErbB2 receptor staining is noted in seven of 28 patients, with five of these seven showing 2+ and 3+ membrane-staining patterns. Adjustment for pathologic grade and age suggests that patients whose tumors express high levels of ErbB2 (2+, 3+) are at increased risk of death compared with patients with low or no expression of ErbB2 (HR, 2.29; p =.32). MUC4 antigen positivity is seen in two of the five cases with 2+ and 3+ staining for ErbB2. CONCLUSIONS.: These findings suggest MUC4 antigen positivity is associated with reduced risk of death and reduced risk of recurrence and may identify a subset of patients with more favorable prognosis. Although limited by small sample size, analysis reveals ErbB2 overexpression is not consistently associated with MUC4 antigen positivity and might be associated with increased risk of death.
Abstract. In recent years mechanical systems have been developed that more closely mimic the full dynamic, physical and biochemical complexity of the GI Tract. The development of these complex systems raises the possibility that they could be used to support formulation development of poorly soluble compounds and importantly may be able to replace clinical BE studies in certain circumstances. The ability of the TNO Simulated Gastro-Intestinal Tract Model 1 (TIM-1) Dynamic Artificial Gastrointestinal System in the 'lipid membrane' configuration to support the development of Biopharmaceutics Classification System Class 2 compounds was investigated by assessing the performance of various AZD8055 drug forms and formulations in the TIM-1 system under standard fasting and achlorhydric physiological conditions. The performance data were compared with exposure data from the phase 1 clinical study. Analysis of the AZD8055 plasma concentrations after tablet administration supported the conclusions drawn from the TIM-1 experiments and confirmed that these complex systems can effectively support the product development of poorly soluble drugs. Particularly, the TIM-1 system was able to show that AZD8055 exposure would increase in an approximately dose proportional manner and not be limited by the solubility or dissolution. Additionally, the investigations also showed that the exposure produced by a solution and a tablet would be the same. Specific instances when the TIM-1 system may not be predictive of clinical product performance have also been identified.
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