THEORY OF SOLUTE AND WATER TRANSPORT ACROSS EPITHELIA

数学模型被用来表示上皮细胞 作为隔间和包围膜和许可证的系统 对正常和病理状态的计算机模拟。这 项目还承担了简化、近似、 数学模型，可用于解释 实验数据。近似解析法的比较 使用具有详细计算机模拟的模型来评估 较简单模型的适用范围。的主要目标是 下一阶段的调查是完成一个模型 近端肾血管单位--包括近端小管， 肾小球和肾小管周围毛细血管。该模型跟踪 Na+，K+，H+，C l-，碳酸盐离子的浓度和通量， 二次磷酸氢离子、一次磷酸氢离子 离子、葡萄糖和尿素。此模拟的主要焦点是 近端肾小管钠重吸收的实验研究 跨血管内皮细胞钠转运途径和驱动力 以及物理因素对此进行调节的机制 重吸收。特别是，这是一种量化的努力 管腔因子和肾小管周围因子对肾小球发育的影响 肾小球滤过和近端重吸收之间的平衡。 第二个病灶是近端小管的表现。 碳酸氢盐重吸收：细胞内定义的转运机制 膜系统将在小管的范围内进行检查 模型，用于酸碱紊乱的模拟。特别的 兴趣是近端肾单位在维持肾功能中的作用。 代谢性碱中毒--定义减少的相互作用 肾小球滤过率、细胞外体积耗竭和 肾小管周围pH升高。下一个目标的第二个目标 研究期间是大脑皮层的表现 收集小管。这一模式将逐步发展 时尚从模拟的蟾蜍和乌龟的膀胱。它 将用来探索小管流、酸碱的相互作用 状态和钠对肾单位钾转运的亲和力 细分市场。

Mathematical models are formulated that represent an epithelium as a system of compartments and bounding membranes and permit the computer simulation of normal and pathological states. This project also undertakes the analysis of simplified, approximate, mathematical models, which may be used in the interpretation of experimental data. Comparison of the approximate analytical models with the detailed computer simulation is used to assess the range of applicability of the simpler models. The major aim for the next period of investigation is the completion of a model of the proximal nephrovascular unit - including proximal tubule, glomerulus, and peritubular capillary. The model tracks the concentrations and fluxes of Na+, K+, H+, C1-, carbonate ion, secondary hydrogen phosphate ion, primary hydrogen phosphate ion, glucose and urea. The primary focus of this simulation is the study of the proximal tubule sodium reabsorption: the transepithelial pathways and driving forces of sodium transport and the mechanisms by which physical factors modulate this reabsorption. In particular, this is an effort to quantify the effects of luminal and peritubular factors which mediate the balance between glomerular filtration and proximal reabsorption. The second focus is the representation of proximal tubule bicarbonate reabsorption: mechanisms of transport defined in cell membrane systems are to be examined in the context of a tubule model, in simulations of the acid-base disturbances. Of particular interest is the role of the proximal nephron in the maintenance of metabolic alkalosis - defining the interplay of decreased glomerular filtration rate, extracellular volume depletion, and increased peritubular pH. A second aim for the next investigational period is the representation of the cortical collecting tubule. This model will be developed in a step-wise fashion from simulations of toad and turtle urinary bladder. It will be used to explore the interaction of tubule flow, acid-base states, and sodium avidity on potassium transport by this nephron segment.