THEORY OF SOLUTE AND WATER TRANSPORT ACROSS EPITHELIA

数学模型被公式化，其将上皮表示为系统 隔室和边界膜，并允许计算机模拟 正常和病理状态。 该项目还承担了 分析简化的、近似的数学模型， 对实验数据的解释。 近似值的比较 分析模型与详细的计算机模拟是用来评估 较简单模型的适用范围。 的主要目标是 下一个调查阶段是完成近端模型 肾血管单位-包括近端小管、肾小球和 管周毛细血管 该模型跟踪的浓度和通量 Na+、K+、H+、Cl-、碳酸根离子、二级磷酸氢根离子、初级 磷酸氢根离子、葡萄糖和尿素。 一进程的主要重点 模拟是近端小管钠重吸收的研究： 钠转运的跨上皮途径和驱动力， 物理因素调节这种重吸收的机制。 在 特别是，这是一个努力量化的影响，流明和 调节肾小球滤过平衡的管周因子 和近端重吸收。 第二个焦点是 近曲小管重吸收：转运机制的确定 在细胞膜系统中， 模型，在模拟酸碱紊乱。 特别 感兴趣的是近端肾单位在维持肾功能中的作用。 代谢性肾小球硬化-定义肾小球减少的相互作用 滤过率、细胞外容量耗竭和肾小管周围增加 博士 下一个研究期的第二个目标是代表性 皮质集合小管的一部分 该模型将以 从蟾蜍和乌龟膀胱的模拟逐步的方式。 它 将用于探索肾小管流动，酸碱状态， 和钠亲合力对肾单位段钾转运的影响。

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+, Cl-, 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.