Erythropoietic stress, macrocytosis, and hemoglobin switching in HbAA sheep.
Erythropoietic stress, macrocytosis, and hemoglobin switching in HbAA sheep.
复制标题
HbAA 绵羊的红细胞生成应激、大红细胞增多症和血红蛋白转换。
作者：
N. Mohandas;M. R. Clark;J. Wyatt;J. Garcia;P. Eisenberg;S. Shohet
对血红蛋白AA纯合子绵羊的血红蛋白转换和大红细胞症进行了研究。突然启动红细胞生成应激，伴随着循环促红细胞生成素水平的脉冲式升高，诱导放血。根据密度在Stractan梯度上分离连续的血液样品，以每天从骨髓中分离新进入循环的细胞。对这些年轻网织红细胞中血红蛋白表型和细胞体积分布的分析显示，血红蛋白C的出现和细胞体积的增加有明显的时间分离。在促红细胞生成素升高的24小时内出现大细胞表明，大细胞症可能是促红细胞生成素在红细胞成熟后期作用的结果。血红蛋白C出现的72小时延迟表明，特定血红蛋白表型的定型发生在分化的早期阶段，涉及不成熟的红系干细胞。这项研究的结果表明，这些后果的红细胞生成的压力是在两个不同的发展阶段启动，导致生产的巨红细胞和血红蛋白转换。
Hemoglobin switching and macrocytosis were studied in homozygous hemoglobinAA sheep. An abrupt initiation of erythropoietic stress, accompanied by a pulsed elevation of circulating erythropoietin levels, was induced by phlebotomy. Sequential blood samples were separated according to density on Stractan gradients to isolate cells newly entering the circulation from the marrow each day. Analysis of hemoglobin phenotype and cell volume distribution in these young reticulocytes revealed a distinct temporal separation in the appearance of hemoglobin C and increased cell volume. The appearance of macrocytes within 24 hr of erythropoietin elevation suggests that macrocytosis could be the result of the action of erythropoietin during the late stages of erythroid maturation. The 72-hr delay in the appearance of hemoglobin C indicates that commitment to a particular hemoglobin phenotype occurs at an early stage of differentiation and involves immature erythroid stem cells. The results of this study show that these consequences of erythropoietic stress are initiated at two different developmental stages, resulting in the production of macrocytosis and hemoglobin switching.