STUDIES OF SICKLING MECHANISMS AND RED CELL MEMBRANES

提出的研究目的是：(1)进一步定义分子 脱氧-硫化氢聚合机理的研究--非S的作用 血红蛋白聚合过程中Hb解离平衡的影响 以及不对称杂化产物在聚合中的作用，并对其进行了具体分析 用溶液数据关联聚合物中的分子间接触位置 (2)官能团的进一步研究。 含红细胞的HB-S的性质；(3)红细胞膜的扩展研究 血红蛋白病和其他疾病患者红细胞膜功能的异常 异常的红细胞。这些研究包括对脱水机理的研究。 通过定义SS细胞的异常离子传输特性，包括 镰刀过程中钙敏感钾通道的瞬时激活 细胞异质性在K+通道钙敏感性中的可能作用 扩散氯离子渗透性，以及钙渗透性和 泵的活性；其他高钙异常红细胞的钙状态， 内吞泡泡的形成和滞留的作用和机制； 以及Hb与红细胞膜的相互作用。我们的方法将包括 HB二元混合物在不同温度下的聚合物溶解度研究 条件，使用示踪剂标记的白蛋白作为非聚合物的标记 相；用停流技术测量配基动力学，以及 密度分级SS的镰状和RBC O2平衡的滞后 细胞和SA红细胞在血浆和生理缓冲液中稳定； ~(45)Ca、~(86)Rb等对SS和其他红细胞示踪通量的研究 同位素.红细胞密度分布变化的监测.比较 生理状态下SS等红细胞阳离子和阴离子通量的研究 和促进脱水的实验模拟条件；电子 内吞作用的显微照相研究及封闭小泡的鉴定 脾切除组与正常对照组、正常对照组和正常对照组比较 溶血状态.冰冻切片的电子探针X射线微区分析 以及对红细胞体积、pH和 在特定条件下的离子组成，可以预测 运输和容量调节假说的实验检验。

The proposed research is aimed at (1) further definition of the molecular mechanisms of deoxy-HbS polymerization, by studies of the role of non-S hemoglobins in polymerization, the effects of Hb dissociation equilibria and asymmetric hybrids in polymerization, and analysis of specific intermolecular contact sites in the polymer by correlating solution data with crystallographic data; (2) further studies of the functional properties of Hb-S containing red cells; and (3) expanded studies of the functional abnormalities of rbc membranes in hemoglobinopathic and other abnormal red cells. These include studies of the mechanism of dehydration of SS cells, by defining their abnormal ion transport properties, including transient activation of the Ca2+-sensitive K+-channel during sickling, the possible role of cell heterogeneity in Ca2+-sensitivity of K+ channels, diffusional chloride permeability, and alterations of Ca permeability and pump activity; the state of Ca in other abnormal rbc with high Ca contents, the role and mechanisms of formation and retention of endocytic vesicles; and interactions of Hb with the rbc membrane. Our methods will include studies of the polymer solubility of binary Hb mixtures under a variety of conditions, using tracer-labelled albumin as a marker of the nonpolymer phase; measurements of the ligand kinetics by stopped-flow techniques, and the hysteresis of sickling and rbc O2 equilibria of density-fractionated SS cells and SA red cells tonometered in plasma and physiological buffers; tracer flux studies of SS and other rbc with 45Ca, 86Rb, and other isotopes; monitoring of density distribution changes of rbc; comparative studies of cation and anion fluxes in SS and other rbc under physiological and experimental modeling conditions promoting dehydration; electron micrographic studies of endocytosis and identification of enclosed vesicles in rbc of splenectomized versus persons with spleen intact, in normal and hemolytic states; electron probe X-ray microanalyses of cryosections of rbc; and computer modeling of the kinetics of changes in rbc volume, pH and ionic composition under specified conditions, which can predict experimental testing of hypotheses about transport and volume regulation.