[Comparative study of radioprotective efficiency of various doses of cystamine dissolved in normal saline solution or distilled water]. / Sravnitel'noe izuchenie radioprotektornoi éffektivnosti razlichnykh doz tsistamina, rastvorennogo v fiziologicheskom rastvore ili distillirovannom vode.

In experiments on mice it has been found that radioprotective effect of cystamin used in a doze 0.15 mg/kg reveals only at its dissolution in a physiological solution, and it is not found out at dissolution of a preparation in distilled water.

[Comparative study of the radiation-protective effectiveness of low doses of cysteamine, heparin, and naphtizine in experiments on mice]. / Sravnitel'noe izuchenie protivoluchevoi éffektivnosti razlichnykh doz tsistamina, geparina i naftizina v opytakh na myshakh.

Experiments were conducted on adult random-bred mice. The animals were exposed to a total single gamma-irradiation with a dose of 7.0 Gy (LD90/30). Drugs were administered prophylactically in a wide range of single doses: cystamin from 0.015 to 150 mg/kg, naphtizin from 0.001 to 10 mg/kg, heparin from 0.025 to 500 units/kg. It was found that the dose-effect curve based on the survival parameters of irradiated animals had two-phase character for cystamin and heparin with maxima of efficiency in the field of low and standard dosage of radioprotectors. Antiradiation effect of naphtizin reached maximum at low concentrations and then went on a plateau at usual radioprotective doses.

[Effect of synthetic polyribonucleotides on the immunological and colony-forming activity of irradiated bone marrow cells]. / Vliiani sinteticheskikh poliribonukleotidov na immunologicheskuiu i kolonieobrazuiushchuiu aktivnost' kletok obluchennogo kostnogo mozga.

The experimental data are presented concerning the effect of polyribonucleotides on the immunologic and colony forming ability of bone marrow or irradiated mice. All the compounds under study exhibited a pronounced, but to a different degree, colony-forming and immunostimulating action. The comparative study of the influence of polyribonucleotides on the number of endogenous colonies and antibody-forming cells showed an inverse relationship between these parameters: The preparations exerting the most pronounced immunostimulating effect had an insignificant colony-forming action and vice versa. This is evidently indicative of the capacity of these preparations to turn the differentiation of haemopoietic stem cells towards the immunopoiesis.

[Effect of heparin on postradiation thymus recovery in mice with various degrees of radiosensitivity]. / Vliianie geparina na postluchevoe vosstanovlenie timusa u myshei s razlichnoi radiochuvstvitel'nost'iu.

BALB/c, random-bred and hybrid (CBA x C57Bl) F1 mice were exposed to a total single irradiation with CO60 gamma-rays (0.2 Gy/min) in doses of 4--6 Gy. Upon sublethal irradiation changes in the thymus mass were biphasic in nature. At the same time the degree of a secondary decrease in the thymus mass depended on radioresistance of the mice. On the 20th day after the irradiation the thymus mass in BALB/c mice (LD50/30 -- 6 Gy) reduced 3-fold, while that in mouse hybrids (LD50/30 -- 7 Gy) 2-fold. Upon heparin injection from day 5 to day 9 after the irradiation (250 units/kg once a day) the postradiation pattern of thymus mass recovery in radiosensitive BALB/c mice was similar to that seen in more resistant F1 hybrids.

[Changes in the processes of bone marrow cell proliferation and differentiation in white mice under the influence of heparin]. / Izmenenie protsessov proliferatsii i differentsiatsii kletok kostnogo mozga belykh myshei pod vliianiem geparina.

In experiments carried out on albino mice daily heparin injections (250 units/kg) for two weeks resulted in 30% increase of leukocyte count in the venous blood. The femur bone marrow kariocyte count remained unchanged, while the leukoerythroblastic ratio rose from 4.1 to 7.6. Autoradiography demonstrated that the duration of the mitotic cycle and its phases in myeloid cells underwent no change, constituting: T--13 hrs, ts--8 hrs, tG2--1 hour, t(G1+M)--4 hrs. In heparinized animals the curve of labeled mitoses was nearly ideal. It is suggested that there occurred a change in the stem cells differentiation towards the myeloid type in the bone marrow under the effect of heparin.

[Influence of heparin on the general adaptation syndrome]. / Vliianie geparina na obshchii adaptatsionnyi sindrom

Administration of heparin led to the block of the alarm reaction of the general adaptation syndrome in rats. The results obtained could be explained by the binding of adrenal cortex hormones by heparin or by an increase in the resistance of tissues to stressors as a result of reversible block of the enzymes of the respiratory energic cycle in the cells.

Heparin-induced hyperplasia of lymphoid tissue.

Experiments on newborn and sexually mature mice and rats showed that repeated injection of heparin leads to an increase both in the number of lymphocytes in the thymus and spleen and in the number of hematopoietic stem cells forming endogenous colonies in the spleen. The lymphoid tissue and the pool of colony-forming units are conjecturally under the regulatory influence of the adrenocortical hormones and of the product of the mast cells-heparin.