[Cytokinetic evaluation of erythropoiesis on prolonged orbital flights].

The purpose of the investigation was to understand better the mechanisms of erythropoietic changes at the cellular level during a prolonged exposure to weightlessness. Following 96-, 140- and 175-day space flights cytokinetic and morphological changes in erythropoiesis were observed. The count of circulating erythrocytes decreased inflight and their life time reduced postflight. The shortening of the life time of erythrocytes postflight was paralleled by increased proliferative activity of erythroid cells. The erythrocytic balance was not reached as late as R + 36. It is recommended that the number of research methods be enlarged.