The effect of short- vs. long-term platelet-activating factor exposure on mouse preimplantation embryo development

Preimplantation mouse embryos (n = 1540) were cultured in the presence of platelet-activating factor (PAF) (10(-7)- 10(-14) mol/l) to the hatched blastocyst stage. A dose-dependent negative correlation (-0.75783) relationship between blastocysts and the concentration of PAF was statistically significantly different (p < 0.001). Long-term but not short-term PAF exposure is detrimental to preimplantation Swiss Webster mouse embryos. Short-term PAF (10(-9) mol/l) exposure was found significantly (p < 0.05) to reduce blastocoel diameter. The effect of PAF during preimplantation development may be genotype dependent and be affected by the culture conditions.     

Age-related changes in gastric mucosal repair and proliferative activities in rats exposed acutely to aspirin

OBJECTIVES: (1) To determine whether and how outcome measurements in the ECASS trial are influenced by a shorter time window (0-3 vs. 3-6 h) between onset of symptoms and start of thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke. (2) To discuss the results of the ECASS 0- to 3-hour cohort with the results of the National Institute of Neurological Disorders and Stroke Study (NINDSS). DESIGN AND ANALYSIS: Analysis of the 0- to 3-hour and the 3- to 6-hour cohort in accordance with the ECASS protocol. Comparative analysis of the ECASS and NINDSS results following the NINDSS protocol using dichotomized endpoints. MAIN OUTCOME MEASURES: Primary endpoints: modified Rankin Scale, Barthel Index; secondary endpoints: combined Barthel/Rankin, long-term Scandinavian Stroke Scale, National Institutes of Health Stroke Scale, mortality at 30 and 90 days, occurrence of intracranial hemorrhage. NINDS trial endpoint: favorable outcome as defined in the NINDS trial. RESULTS: In ECASS, 87 patients were randomized within 3 h of stroke onset. Differences in favor of rt-PA treatment can be found for all primary and secondary outcome measures in the ECASS 0- to 3-hour cohort, except for mortality at day 30, which is somewhat higher in the rt-pA-treated group. However, due to the small sample size, the differences do not reach statistical significance. Early infarct signs (as defined by the ECASS protocol) are found as early as 2 h after stroke onset. Parenchymal hemorrhages are found significantly more often among rt-PA-treated patients. The results in the ECASS 0- to 3-hour cohort fit well with the results in NINDSS. CONCLUSION: Data from the 3-hour ECASS cohort support the efficacy of early thrombolytic therapy in acute hemispheric stroke patients. Comparing bleeding complications between the ECASS and NINDSS is difficult because of differences in the definition and occurrence of hemorrhagic events.     

Alcohol's impact upon glycobiology

This report reviews and illustrates ways in which some of the problems linked to excessive alcohol intake may develop from alcohol-induced alterations of eukaryotic cell surface molecules. Alcohol is the number one drug of abuse in the US, affecting at least 15 million Americans and causing annual losses of more than $80 billion and 100,000 lives. An estimated 20-40% of all persons admitted to general hospitals have alcohol-related problems and are often undiagnosed alcoholics being treated for the consequences of their drinking. Chronic alcohol-related cirrhosis of the liver is the ninth leading cause of death in the US, with over 28,000 deaths annually. Alcohol has harmful effects on almost every organ system in the body, producing cardiovascular disorders, liver disease, neuropathological illness and fetal injury. The etiologic mechanisms for these effects of alcohol is a research area of considerable importance to the National Institute for Alcohol Abuse and Alcoholism.     

求解背包问题的病毒协同进化粒子群算法

为提高粒子群算法的搜索性能,提出一种基于病毒进化理论的改进离散粒子群算法:病毒协同进化粒子群算法.在粒子群中引入生物病毒机制和宿主与病毒基于感染操作的思想,病毒采用与粒子等长的编码方式,执行反向代换、结合等操作,利用病毒的水平感染和垂直传播能力较好地维持个体的多样性和对解空间的局部搜索能力.通过解决背包问题对算法进行验证,仿真表明所提算法搜索性能优于遗传算法、模拟退火及标准粒子群等其他算法.该算法能有效求解背包问题等NP难题.     

面向不同利益相关者的IT投资决策模型

为了响应不同利益相关者在IT投资决策过程中的不同需求,把备选项目看作一个组合,综合IT项目的战略对应和财务收益为目标,权衡其成本、收益和风险,构建基于模糊多目标规划的IT投资决策模型,其中模糊数用来刻画不确定的项目信息。通过改变各临界值和求解过程中产生的参数,模型支持各种假设分析。最后用案例说明模型的用法和功能。