NMR STUDIES OF SICKLE ERYTHROCYTE METABOLISM

镰状细胞性贫血(SSA)是一种慢性、衰弱的疾病，会导致 痛苦、血管闭塞的危象和进行性器官衰竭。了解以下内容 调节完整红血球中镰刀过程的因素将 提供对体内镰状的病理生理学的更多了解， 并将提供测试潜在抗呕吐药物的方法。核子 磁共振(核磁共振)光谱学是一种强大的设备 从完整的细胞中非破坏性地获取生化信息。P-31 核磁共振波谱将用于关联细胞内pH和2，3-DPG-Hb 与细胞体积、Hb浓度和Hb-氧亲和力的结合 完整的、正常的和镰状的细胞。这些关系首先将是 在模型系统中探索，在该模型系统中细胞体积由 细胞渗透压和溶质组成的调节 停职。这个模型将被比作一个红细胞体积 已经被潜在的抗呕吐药物增加，这些药物使细胞 对钠(碲酸盐、西替二醇)具有渗透性或被其他物质降低的膜 增加对K(呋喃霉素)渗透性的药物。红血球来自 然后，SSA患者将通过不连续的方式分开 阿拉伯半乳聚糖密度梯度离心法在亚种群中的应用 接连增加密度。利用P-31核磁共振，细胞内的pH， 2，3-DPG的浓度和2，3-DPG与HBS的结合程度 将估计亚群，并与以下预测值进行比较 基于细胞体积、Hb浓度和Hb-氧的模型体系 亲和力。这些研究将检验假设中的致密细胞 由于进行性失水和HBS增加，SSA的pH值较低 浓度，以及降低HBS的抗呕吐剂 浓缩液可通过提高 胞内pH。这些亚群中的平均细胞年龄将是 从丙酮酸激酶活性估计，和C-13核磁共振将用于 研究糖酵解代谢率。将确定是否 糖酵解活性反映了镰刀的平均年龄更小。 细胞，或者这种活动是否被镰刀过程改变。通过 在血管闭塞期间对SSA患者进行这些实验 在危机和健康期间，将确定是否有变化 镰状细胞亚群的生理特性可以与 与血管闭塞状态的发展有关。

Sickle cell anemia (SSA) is a chronic, debilitating illness that leads to painful, vaso-occlusive crises and progressive organ failure. Knowledge of the factors which regulate the sickling process in the intact red cell will provide a greater understanding of the pathophysiology of sickling in vivo, and will provide methods for testing potential antisickling drugs. Nuclear magnetic resonance (NMR) spectroscopy is a powerful device for nondestructively obtaining biochemical information from intact cells. P-31 NMR spectroscopy will be used to relate intracellular pH, and 2,3-DPG -Hb binding to cell volume, Hb concentration and Hb - oxygen affinity in intact, normal and sickle cells. These relationships will first be explored in a model system in which the cell volumes are altered by adjustment of the osmolarity and solute composition of the cell suspension. This model will be compared to one in which red cell volumes have been increased by potential antisickling drugs that render cell membranes permeable to Na+ (tellurite, cetiedil), or decreased by other drugs that increase the permeability to K+ (valinomycin). Red cells from SSA patients will then be separated by means of discontinuous arabinogalactan gradient density centrifugation into subpopulations of succeedingly increasing density. Using P-31 NMR, the intracellular pH, 2,3-DPG concentration and the degree of 2,3-DPG - HbS binding for each subpopulation will be estimated, and compared to the values predicted by the model systems, based on cell volume, Hb concentration and Hb - oxygen affinity. These studies will test the hypotheses that the dense cells in SSA have lower pH as a result of progressive water loss and increasing HbS concentration, and that antisickling agents that act to decrease HbS concentration may provide additional antisickling action by raising intracellular pH. The average cell ages in these subpopulations will be estimated from pyruvate kinase activities, and C-13 NMR will be used to study rates of glycolytic metabolism. It will be determined whether glycolytic activity is a reflection of the younger average age of sickle cells, or whether this activity is altered by the sickling process. By performing these experiments on SSA patients both during vaso-occlusive crisis and during good health, it will be determined whether alterations in the physiologic properties of the sickle cell subpopulations can be related to the development of the vaso-occlusive state.