Survival and Repopulation of Irradiated 'Pre-Cfu-C' In Mice |
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Authors: | Shin Aizawa&dagger ,Ichita Amaki,Takeshi Miyanomae&dagger ,Masahito Tsurusawa&dagger ,Kazuhiro J. Mori&dagger |
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Affiliation: | First Department of Internal Medicine, Faculty of Medicine, Nihon University, Tokyo 173, Japan;Department of Microbiology, Faculty of Medicine, Kyoto University, Kyoto 606, Japan |
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Abstract: | ABSTRACT Supernatants of murine bone-marrow cultures contain a colony-promoting factor (CPF) which increases the number of granulocyte and macrophage colonies in semi-solid agar cultures in the presence of colony-stimulating factor (CSF). Incubation of bone-marrow cells with CPF results in an increase in the number of granulocyte/macrophage progenitor cells (CFU-c) and the CPF-responsive cells may be younger than the CFU-c. We have investigated the radiosensitivity and the pattern of the recovery after irradiation of CPF-responsive cells. We found that the radiosensitivity of CPF-responsive cells was significantly lower than those of CFU-c. burst-forming units-erythroid (BFU-e) and pluripotent stem cells in vivo (CFU-s) and in vitro (CFU-mix). the CPF-responsive cells remained subnormal even at 28 days after irradiation of the mice, a time when the CFU-s and CFU-c had recovered completely. Therefore the CPF-responsive cells may constitute a separate compartment, namely ‘pre-CFU-c’, in the maturation sequence of granulopoiesis, and this maturation of the ‘pre-CFU-c’ to CFU-c seems to be highly stimulated after irradiation to counterbalance the influx from CFU-s. |
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