Dynamics of cell proliferation in the bone marrow of irradiated mice, using certain factors with a protective effect.

Cell proliferation was studied in the bone marrow of irradiated mice in relation to the use of certain protective factors. The mitotic Index, the incidence of chromosomal aberrations and the proportion of individual mitotic figures were studied. The protective effect of cysteine and artificial hypothermia was manifested in all the given mitotic indicators. In experiments with homologous bone marrow, the optimal interval between irradiation and bone marrow transplantation was determined. The results showed that proliferation of the injected bone marrow was not satisfactory if the interval was longer than 24 hours. The hypothesis that homologous bone marrow undergoes a change in an irradiated hosts resulting in abnormal mitosis, was submitted. The finding of an increase in the number of metaphases in the dividing bone marrow cell population at a given interval after irradiation was reverified. This anomaly is due to the direct effect of radi ation on bone marrow and was not observed after other forms of stress. (auth)