SHEAR STRESS ENHANCED SOLUTE TRANSPORT ACROSS MEMBRANES

剪切应力增强溶质跨膜运输

• 批准号: 3467373
• 负责人: TODD D GIORGIO
• 金额: $ 11.24万
• 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/3467373
• 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.

提出的研究计划重点是钙离子内流的研究 作为流体剪切力的函数通过细胞膜。 血液 血小板和内皮细胞将被独立研究， 确定剪切应力增强的跨膜钙离子的影响 细胞内游离钙离子浓度。 的影响 剪切应力的扩散和对流输运的其他 生物学上重要的物质也将被检查。 洞察 流体机械细胞活化的起始步骤将是 寻找。 拉伸应力对流体动力学血小板的影响 将对激活进行评估。 用锥板粘度计连续进行测量， 平行板流动室或“拉伸流动流变仪”。每个 修改用于荧光和发光测量。 细胞内 钙离子浓度、细胞内pH、膜电位和 血小板致密颗粒释放将在 流体压力暴露。 旋转腔室的几何形状允许 对整个样品施加均匀、良好描述的剪切场 音量. 平行板装置可以施加良好描述的剪切 贴壁细胞的应力 室。 “拉伸流动流变仪”产生均匀， 恒定加速度，导致应用恒定 流体动力拉伸力 拟定的研究将利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解耦 以清晰明确的方式从正常细胞中测量 钙离子稳态的过程。 血小板膜的作用 蛋白质在管理钙离子通量将进行调查 通过从分离的血小板膜制备脂质体。 Tbe 心血管液体应激对心血管流出动力学的影响 还将研究来自脂质体的药物。 从实验中获得的结果将纳入一个 剪切应力增强细胞转运的数学模型 膜。 将制定一个预测方案， 作为物理系统的函数， 参数和流体动力学暴露。