RESUMO
The combiened effects of different dose rates (0.625 microGy/s - 1.1 mGy/s) of gamma-irradiation and of cuprum and of cadmium ions on the haematopoietic system of rats were studied. It was found that only low dose rates (0.625-10 microGy/s, summary doses 0.5-2.0 Gy) of gamma-irradiation yields in the increasing proliferative activity of bone marrow. The number of myelocariocytos in S-phase was increased at 1.5-1.8 times. In case of the treatment with both cadmium chloride and radiation the changes in proliferative activity of bone marrow are completely due to the radiation factor. Combination of cuprum acetate and ionizing radiation induce opposite effects providing formal normalization of the haematopoietic characteristic of bone marrow up to 3, 6 and 12 months after the end of the radiation and the chemical exposure of the animal.
