ABSTRACT
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. Functional deficiency of circulating cells was evaluated by the resistance of erythrocytes to acid lyse and the activity of the main antioxidant enzymes--superoxide dismutase (SOD) and catalase (CAT). The minimum "threshold" doses of radiation that cause systemic reactions occur in the range of units of miligrey.
Subject(s)
Catalase/blood , Erythrocytes/radiation effects , Radiation Dosage , Superoxide Dismutase/blood , Animals , Catalase/radiation effects , Erythrocytes/enzymology , Gamma Rays , Male , Rats , Superoxide Dismutase/radiation effectsABSTRACT
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.
Subject(s)
Bone Marrow Transplantation , Bone Marrow , Gamma Rays/adverse effects , Hematopoietic Stem Cells , Oligopeptides/pharmacology , Radiation-Protective Agents/pharmacology , Animals , Bone Marrow/drug effects , Bone Marrow/radiation effects , Colony-Forming Units Assay , Dose-Response Relationship, Drug , Female , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/drug effects , Hematopoietic Stem Cells/radiation effects , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Oligopeptides/chemistry , Radiation-Protective Agents/chemistry , Structure-Activity RelationshipABSTRACT
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.
Subject(s)
Body Weights and Measures , Dose-Response Relationship, Radiation , Embryonic Development/radiation effects , Animals , Female , Gamma Rays , Pregnancy , Rats , Rats, WistarABSTRACT
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. Various ways of administration of the peptidomimetics studied were used in the in vivo experiments: intravenous, intraperitoneal or subcutaneous injections and oral administration in the dose range of 10-10000 microg/kg. As a result of our work, we have discovered 2,5-diketopiperazine peptidomimetic derivatives with the dual activity: stimulation of intact committed SFU-S and radiomodifying activity.
