EFFECTS OF PHYSICAL FORCES ON PLATELETS

拟议的计划侧重于阐明动力学和 切变场中血小板反应的机制。人体血小板数 将在全血和一些不同的混悬液中进行研究 在添加和不添加激动剂的情况下，受测量的已知水平的 剪切应力，并检查是否有反应的证据。旋转 将使用粘度计，以使非常广泛的应力水平和 暴露时间可以在严格控制的条件下进行研究。基本信息 血小板反应的指标将包括剪切场中的聚集， 版本和功能变化。大部分重点将放在其他方面 如下所述的血小板反应指标。 旋转粘度计将安装光学检测系统，以便 这种血小板反应可以在剪切场中直接监测。三 将监测血小板反应的指标：(1)聚集， 以光密度变化表示；(2)致密颗粒释放，其次 通过测量ATP-荧光素-荧光素酶发光；以及(3) 细胞内钙离子动员，随后使用光探针。 剪切力暴露对花生四烯酸(AA)速率的影响 摄取将被确立。将对分布进行测量 在磷脂、中性脂和游离脂肪酸中。代谢物 将测量AA的含量，并研究血小板受体的变化 直接和间接的。将研究血小板受体糖蛋白 通过使用针对特定血小板的单抗 感受器。 其他研究将确定剪切场对 对vWF(von Willebrand因子)多聚体形式的血小板的附着 在正常血浆中，异常大的vWF多聚体产生和 由人内皮细胞分泌。

The proposed program is focused on elucidation of the kinetics and mechanisms of platelet response in a shear field. Human blood platelets will be studied in whole blood and in a number of different suspensions with and without added agonists, subjected to measured, known levels of shear stress, and examined for evidence of response. Rotational viscometers will be used so that a very wide range of stress levels and exposure times can be studied under closely controlled conditions. Basic indices of platelet response will include aggregation in the shear field, release and functional changes. Most of the emphasis will be on other indicators of platelet response as outlined below. A rotational viscometer will be fitted with optical detection systems so that platelet response can be monitored directly in the shear field. Three indicators of platelet response will be monitored: (1) aggregation, indicated by optical density changes; (2) dense granule release, followed by measuring ATP - luciferin - luciferase luminescence; and (3) intracellular calcium ion mobilization, followed through use of photoprobes. The influence of exposure to shear stress on rates of arachidonic acid (AA) uptake will be established. Measurements will be made of the distribution amongst phospholipids, neutral lipids, and free fatty acids. Metabolites of AA will be measured and platelet receptor changes will be studied both directly and indirectly. Platelet receptor glycoproteins will be studied by use of monoclonal antibodies directed against specific platelet receptors. Other studies will determine the influence of the shear field on the attachment to platelets of the vWF (von Willebrand Factor) multimeric forms in normal plasma, and the unusually large vWF multimers produced and secreted by human endothelial cells.