SHEAR STRESS ENHANCED SOLUTE TRANSPORT ACROSS MEMBRANES

剪切应力增强溶质跨膜运输

• 批准号: 3467375
• 负责人: TODD D GIORGIO
• 金额: $ 9.35万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3467375
• 关键词: acidity /alkalinity; adenine nucleotides; animal tissue; biological fluid transport; body fluid viscosity; calcium channel blockers; calcium flux; cell membrane; cytolysis; diffusion; fluorescence spectrometry; granule; homeostasis; ion transport; liposomes; luciferin; luciferin monooxygenase; mathematical model; membrane model; membrane permeability; membrane potentials; membrane proteins; model design /development; nonblood rheology; pharmacokinetics; platelet activation; platelet aggregation; platelets; prostaglandins; tissue /cell culture; vascular endothelium

The proposed research plan is focused on the study of calcium ion influx through cellular membranes as a function of fluid shear stress. Blood platelets and endothelial cells will be studied independently to determine the impact of shear stress-enhanced transmembrane calcium ion flux on intracellular free calcium ion concentration. The effect of shear stress on the diffusional and convective transport of other biologically important substances will also be examined. Insight into the initiating steps of fluid mechanical cellular activation will be sought. The influence of elongational stress on fluid dynamic platelet activation will be evaluated. Measurements will be made continuously with a cone and plate viscometer, a parallel plate flow chamber or an 'elongational flow rheometer'. each modified for fluorescence and luminescence measurement. Intracellular calcium ion concentration, intracellular pH, membrane potential and platelet dense granule release will be monitored continuously during fluid stress exposure. The rotational chamber geometry permits application of a unifom, well-described shear field to the entire sample volume. The parallel plate apparatus can apply well-described shear stress to anchorage-dependent cells attached to one wall of the flow chamber. The 'elongational flow rheometer' produces a flow of uniform, constant acceleration which results in the application of a constant fluid dynamic stretching force. Proposed studies will utilize unilamellar liposomes as model cell membranes. Use of liposomes will decouple the calcium ion flux measurement in a clear and unambiguous way from the normal cellular processes of calcium ion homeostasis. Tbe role of platelet membrane proteins in the management of calcium ion flux will be investigated through preparation of liposomes from isolated platelet membranes. Tbe effect of cardiovascular fluid stress on the efflux kinetics of pharmaceuticals from liposomes will also be studied. The results obtained from experiment will be incorporated into a mathematical model of shear stress enhanced transport through cell membranes. A predictive scheme will be developed to estimate the degree of shear stress induced transport as a function of physical system parameters and fluid dynamic exposure.

建议的研究计划重点是研究钙离子内流。 通过细胞膜作为流体剪切力的函数。血样 将对血小板和内皮细胞进行独立研究 测定剪切力增强的跨膜钙离子的影响 通量对细胞内游离钙离子浓度的影响。的影响 其他物质扩散和对流输送中的剪切力 还将检查具有生物重要性的物质。洞察 流体机械细胞激活的启动步骤将是 被追寻。拉伸应力对流体动力血小板的影响 将对激活进行评估。 将使用锥板粘度计连续进行测量， 平行板流变室或“拉伸式流动流变仪”。每一个 针对荧光和发光测量进行了改进。细胞内 钙离子浓度、细胞内pH、膜电位和 将持续监测血小板致密颗粒的释放 体液压力暴露。旋转室的几何形状允许 将统一的、描述良好的剪切场应用于整个样品 音量。平行板装置可以应用所描述的剪切 附着在流的一个壁上的锚定依赖细胞的应力 密室。“拉伸式流动流变仪”产生均匀的流动， 恒定加速，其结果是应用一个常量 流体动态拉伸力。 拟议的研究将使用单层脂质体作为模型细胞 膜。脂质体的使用将使钙离子通量去偶联 从正常细胞以清晰和毫不含糊的方式进行测量 钙离子动态平衡过程。血小板膜的作用 将研究在钙离子通量管理中的蛋白质。 通过从分离的血小板膜制备脂质体。待定 心血管液体应激对血管外排动力学的影响 来自脂质体的药物也将被研究。 从实验中获得的结果将被合并到一个 剪应力强化细胞输运的数学模型 膜。将开发一种预测性方案来估计程度 剪切应力引起的输运作为物理系统的函数 参数和流体动态曝光。