OXIDATION AND DEFORMATION IN SICKLE RBC DEHYDRATION

镰状红细胞膜异常，这是最明显的牵连 镰刀病的病理生理学是导致异常的缺陷。 阳离子动态平衡，最终导致细胞脱水。这个 目前的研究将检查一种新的钾泄漏途径，它反映了 过氧化和细胞变形的协同不利影响。这个 所使用的模型是含氧正常的椭圆形变形模型 和被过氧化干扰的红细胞。这种变形是通过以下方式实现的 切应力在粘性悬浮介质中的应用 同心圆筒粘度计。将实现五个目标。第一，要 阐明过氧化损伤的哪些方面是导致 协同泄漏途径，我们将把过氧化损伤剖析为其 各个组成部分使用正常红细胞的选择性操作来查看 如果他们模拟协同泄漏的话。第二，我们将研究 这一协同渗钾途径的生物物理特征 在过氧化加变形过程中观察到的。一些研究将使用 检验粘结性和材料的细观力学方法 红细胞膜脂类提取物重组脂质体的性质。 其他研究将检验增效剂的离子选择性(如果有的话)。 泄漏途径，以及相关的活化能和孔尺寸和 每个发育的细胞的数量。将与之直接比较 给氧和给氧的镰状红细胞。第三，可能的关联性 我们将研究这种钙稳态的泄漏途径。 可能的(过氧化)阈值，超过该阈值协同泄漏 PATH发展成钙依赖。第四，我们将确定是否 这种泄漏途径暴露在变形的镰刀状红细胞本身中。这 将通过检查椭圆变形期间的K+泄漏来解决 氧合镰刀状红细胞和脱氧诱导的红细胞变形 正常(或受扰)的红细胞膜可逆地负载HBS。最后， 我们将确定相关数据是否支持 镰状红细胞的自氧化损伤及其协同作用的发展， 过氧化加变形K+泄漏途径。总的来说，这些 研究将充分定义这种协同泄漏途径，并确定 它是否在镰状红细胞中起作用(因此，它是一个潜在的 导致镰状红细胞脱水)。

The sickle RBC membrane abnormality that is most clearly implicated in sickle disease pathophysiology is that defect which confers abnormal cation homeostasis and, ultimately, leads to cellular dehydration. The present studies will examine a novel potassium leak pathway that reflects synergistic adverse effects of peroxidation and cellular deformation. The model to be used is that of elliptical deformation of oxygenated normal and peroxidatively-perturbed RBC. This deformation is achieved by application of shear stress to RBC in viscous suspending medium using a concentric cylinder viscometer. Five aims will be pursued. First, to clarify what aspects of peroxidative damage are responsible for the synergistic leak pathway, we will dissect peroxidative damage into its various component parts using selective manipulations of normal RBC to see if they simulate the synergistic leak. Second, we will examine the biophysical characteristics of this synergistic potassium leak pathway observed during peroxidation-plus-deformation. Some studies will use micromechanical methods to examine the cohesiveness and material properties of liposomes reconstituted from RBC membrane lipid extracts. Other studies will examine the ion selectivity (if any) of the synergistic leak pathway, as well as relevant activation energies and pore size and number per cell that develop. Direct comparison will be made with oxygenated and deoxygenated sickle RBC. Third, the possible relevance of this leak pathway to calcium homeostasis will be examined as will a possible threshold (of peroxidation) beyond which the synergistic leak pathway develops a calcium-dependence. Fourth, we will determine whether this leak pathway is exposed in deforming sickle RBC themselves. This will be addressed by examining K+ leak during elliptical deformation of oxygenated sickle RBC and during deoxygenation-induced deformation of normal (or perturbed) RBC membranes reversibly loaded with HbS. Finally, we will determine whether correlative data support a relationship between autoxidative damage in sickle RBC and development of the synergistic, peroxidation-plus-deformation K+ leak pathway. In aggregate, these studies will fully define this synergistic leak pathway and determine whether it is operative in sickle RBC (and is, therefore, a potential contributor to sickle RBC dehydration).