POSTIRRADIATION PARAMETERS OF MARROW CELL MYTOTIC CYCLE

The study was performed of mytotic cycle stage distribution (G1/0, S, G2+M) by means of flow cytometry in rats irradiated locally and totall y 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. Lo garithmic dependence of the quantity, of cells synthetizing DNA on rad iation dose occurred in the animals in the range 0.5-6 Gy 24 hours aft er the exposure. investigation of the patients' sternal puncture biops ies indicated that the proportion of S-stage cells and the value S/(G2 +M) are significant diagnostic markers of more than 1 Gy irradiation 2 4-48 h after the exposure. For establishing radiation overdosage these parameters proved much more informative than hemocytological indices (myelogram).