[Study of the influence of low-dose γ-irradiation on the functional state of peripheral blood erythrocytes of rats].

Low-intensity radiation at the absorbed dose of 4 μGy/min is a stressor of medium strength. In male Wistar rats, a pronounced and long-lasting response occurs in the system of red blood cells at the accumulated dose of 4.8 mGy.

[Effect of synthetic tripeptides on hemopoietic stem cells in norm and after gamma-irradiation].

Our work was aimed at researching into the influence of dipeptide (gamma-dGlu-dTrp) "Timodepressin" and this dipeptide-based tripeptides on the colony-forming ability of the irradiated in vitro bone marrow and hemopoietic stem cells of the normal organism. Also studied was the effect of various doses (1-1000 microg/kg) of one oftripeptides (dAla-gammadGlu-dTrp) on the output of exogenous splenic colonies in the case of its introduction 48 hours before irradiation. It is shown that the mode of influence of the preparations produced on the basis ofdipeptides dGlu-dTrp and gamma-dGlu-dTrp on the initial stages ofa hemopoiesis in the normal and irradiated organism depends on the nature of the additional amino-acid residue and its optical orientation.

[Experimental assessment of embryotoxic action of low intensity ionizing irradiation in different periods of intrauterine development].

The prolonged ionizing radiation exposure at the absorbed doze rate of 2.6 mGy/hour and the total accumulated doze of about 20 cGy during different periods of the intrauterine development caused disorders of a coordinated development of organs and the decrease of endurance in physical activity in the postnatal ontogenesis of the irradiated posterity. The results obtained are comparable to the consequences of irradiation exposure of the fetus at the accumulated doze of 125 cGy during all stages of pregnancy and give grounds for considering radiation exposure at the above-mentioned rate (20 cGy) as a biologically significant factor.

[Influence of peptide derivatives of diketopiperazines on hemopoietic stem cells of an intact organism and irradiated bone marrow cells in vitro].

We have performed structural and functional studies of the hemotropic activity for a number of novel 2,5-diketopiperazine peptidomimetic derivatives. We employed a mouse model of hemopoietic stem cells cloning in the spleen of lethally irradiated animals. Biologic activity of synthetic products was studied in two experimental models: 1) in vitro irradiated bone marrow SFU-S was used for studying the radio modifying activity; 2) the biological effect of peptidomimetics on the intact non-irradiated bone marrow was evaluated in vivo.