[Mouse serum inhibition of cytotoxicity of goat antibodies against mouse thymocytes].

It is shown that the serum of Balb/c, C57Bl/6 and F1(C57Bl/6 x CBA) mice inhibits cytotoxicity of goat antithymocyte antibodies. The addition of the serum into the incubation medium increases the proportion of alive cells from -5% up to 95%. Cytotoxicity was also inhibited by the globulin fraction of the mice serum.

[Possible role of the thymus in the mechanism of the adjuvant effect of retinoic acid].

Administration of retinoic acid and of its esters into experimental animals stimulated proliferation of thymus lymphocytes, decreased the tetraploid lymphocytes and increased the amount of diploid cells. The thymus mass tended to decrease as a result of contraction in the area of the gland cortical layer. Alterations in blood, which occurred in presence of retinoic acid, may be responsible for the effect observed.

[Erythrocyte-damaging and immunomodulating effect of retinoids].

The influence of retinyl acetate, retinoic acid and its esterified cis- and trans-derivatives, retinoids C15 and C20 on erythrocytes, liver macrophages and white pulp of the spleen was studied in the experiments on mice of different strains. It was found that administration of these compounds leads to the damage of the blood cells, increase in the number of liver macrophages and the share of white pulp in the spleen and stimulation of the local response to tuberculin. The interdependence of changes in the blood and adjuvant is suggested.

[Effect of retinoids on the development and growth of experimental tumors].

The ability of six retinoids to inhibit cancer growth was tested on mice with Lewis lung carcinoma, PRG and RSM-5 tumors. It was shown that all tumors possess individual sensitivities to retinoids. The most effective substances were: methyl retinoate (all-trans and 13-cis isomers) and a retinoid with a small side chain and an oxidated beta-iononic ring (substance 3).

[Erythrocyte changes from the administration of excess doses of retinoids].

It has been shown that all-trans-methylretinoate, 13-cis-methyl retinoate and retinoid C15 administered intraperitoneally in the form of 0.05% solutions in excess doses reduce the red cell count, hemoglobin content, and osmotic resistance of red cells in C57Bl/6 mice. Administration of 13-cis-methylretinoate and retinoid C15 resulted in the increase of the number of cells uncapable to stain with paraldehyde fuchsin.