[The mitotic cycle parameters of bone marrow cells after irradiation]

The study was performed of mitotic cycle stage distribution (G1/0, S, G2 + M) by means of flow cytometry in rats irradiated locally and totally and in 25 cancer patients receiving radiotherapy. Radiation effects manifested themselves in diminished percentage of cells in S-stage, in the block G2 + M reflecting the direct affection of myelokaryocytes. Logarithmic dependence of the quantity, of cells synthetizing DNA on radiation dose occurred in the animals in the range 0.5-6 Gy 24 hours after the exposure. Investigation of the patients' sternal puncture biopsies indicated that the proportion of S-stage cells and the value S/(G2 + M) are significant diagnostic markers of more than 1 Gy irradiation 24-48 h after the exposure. For establishing radiation overdosage these parameters proved much more informative than hemocytological indices (myelogram).