CELL BIOLOGY OF MEGAKARYOCYTOPOIESIS

骨髓巨核细胞产生血小板， 它们的细胞质碎裂和碎片的释放 进入血液 有相当多的证据表明 巨核细胞的成熟是由 循环血小板群体通过体液机制。 一 血小板生成刺激的来源是 贫血的动物 一定比例的血浆 刺激体内血小板生成。 因此， 分离的血小板减少血浆 将研究巨核细胞。 两种体外刺激剂 巨核细胞集落、白细胞介素-3和巨核细胞集落 增效剂，也将研究其对孤立的 巨核细胞 这些研究将使用 确定巨核细胞是否 成熟可以控制在可识别的水平， 巨核细胞 这些药物对巨核细胞的作用 将在三个方面进行研究：代谢，形态学和 成熟 使用放射性标记的前体，蛋白质合成和 将研究磷酸化和脂质合成。 分析 材料将使用电泳和 色谱程序。 糖酵解将由以下人员进行研究： 测量葡萄糖摄取和乳酸产生。 形态 将使用相位和扫描和 透射电子显微镜 细胞骨架结构将是 用免疫荧光和免疫电子 显微镜 将使用脉冲追踪研究成熟度 实验与3 H-胸苷和以下的运动 通过连续的成熟水平标记， 瑞-姬染色标本。 也影响到 将研究巨核细胞倍性分布。 此外 荧光激活细胞分选将用于分离 巨核细胞倍性。 分离的细胞，将用于 研究可能的代谢差异， 不同倍性的巨核细胞。 这些研究提供了 生物化学研究的长期计划的基础， 巨核细胞成熟期间发生的代谢变化， 以及解释血小板生成的作用机制 细胞水平的刺激物。 此外，这些研究可能 导致用于纯化的有用的体外测定， 血小板生成素。 总的来说，更好地了解控制 巨核细胞生成将是该项目的成果。

Bone marrow megakaryocytes give rise to blood platelets by fragmentation of their cytoplasm and release of the fragments into the blood stream. There is considerable evidence that megakaryocyte maturation is controlled by changes in the circulating platelet population via a humoral mechanism. One source of a thrombopoietic stimulation is the plasma of thrombocytopenic animals. A certain fraction of this plasma stimulates platelet production in vivo. Therefore, the effect of fractionated thrombocytopenic plasma on isolated megakaryocytes will be studied. Two in vitro stimulators of megakaryocytic colonies, interleukin-3 and megakaryocyte colony potentiator, will also be studied for their effects on isolated megakaryocytes. These studies will be performed with the intention of determining whether or not megakaryocyte maturation can be controlled at the level of the recognizable megakaryocyte. The effect of these agents on megakaryocytes will be investigated in three areas: metabolism, morphology and maturation. Using radiolabeled precursors, protein synthesis and phosphorylation and lipid synthesis will be studied. Analysis of material will be performed using electrophoretic and chromatographic procedures. Glycolysis will be studied by measuring glucose uptake and lactic acid production. Morphology will be investigated using phase and both scanning and transmission electron microscopy. Cytoskeletal structures will be studied using immunofluorescence and immunoelectron microscopy. Maturation will be studied using pulse chase experiments with 3H-thymidine and following the movement of label through successive levels of maturation as determined by Wright-Giemsa stained specimens. Also the effect on megakaryocyte ploidy distribution will be studied. In addition fluorescent activated cell sorting will be used to separate megakaryocytes by ploidy. The separated cells, will be used to investigate the possible metabolic differences between megakaryocytes of different ploidys. These studies provide the basis for a long term program on the study of biochemical and metabolic changes that occur during megakaryocyte maturation, as well as explaining the mechanism of action of thrombopoietic stimulators at the cellular level. In addition these studies may lead to a useful in vitro assay for the purification of thrombopoietin. Overall, a better understanding of the control of megakaryocytopoiesis will be the outcome of this project.