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Abstract Six compounds of the 5(7)-alkylamino-6-nitroazolopyrimidine and 8-alkylazolo[5,1-b]purine series were selected based on the structural analysis of A1 adenosine receptor inhibitors and the role of this biological target in the modulation of intraocular pressure, an important factor in the pathogenesis of glaucoma. These heterocycles were shown to exhibit a weak affinity towards the A1 adenosine receptor on an in vitro model of the adenosine-dependent change of the chronotropic effect on isolated atria of white mice. On the other hand, thiadiazolo[3,2-a]pyrimidines and triazolo[5,1-b]purine displayed an in vivo hypotensive effect in rats. The leading compound, 5-methyl-8-(hydroxyethyl)triazolo[5,1-b]purine) (0.2% solution), caused a 34% reduction of ophthalmotonus in 3 h without an adverse resorptive effect. In addition, using the MTT-test it was shown on the human HepG2 cell line that the heterocycles affecting the intraocular pressure were by one to two orders of magnitude less cytotoxic than the reference doxorubicin.

The effects of impaza on ovulatory cycles, sexual behavior, and conception processes were studied in female rats. A two-week course of impaza in doses of 3 and 15 ml/kg did not affect alternation of estrous cycle phases, the incidence of estrus reducing. Sexual behavior of these females was characterized by activation of the receptive sexual motivations; conception was characterized by a higher fertility index and a lower fetal mortality.

The results of a study of a new synthetic drug dimephosphon used as a pathogenetic means in the treatment of experimental tuberculosis are presented. Dimephosphon was found to be responsible for both the in vivo and in vitro decrease of the degree of MBT resistance to rifampicin. The findings of macroscopic, histologic and bacteriologic examinations demonstrated a significant increase in the effectiveness of antituberculous therapy. Dimephosphon monotherapy in mice elicited manifested stimulation of peritoneal macrophages: increase in O2- production, and decline in extracellular 5-nucleotidase activity. Nemolysine-synthetic cellular splenic activity in mice rose essentially. No direct stimulating influence of dimephosphon on functional macrophage activity in vitro was found.

The effects were studied of the degree of immunodeficiency produced by thymectomy of one-month-old rats on the course of experimental tuberculosis induced 3, 6 and 9 months after thymectomy. Subject to study was also the effect of immunodeficiency correction with thymalin on the tuberculous process. It was established that the lungs of thymectomized rats infected 9 months after the thymectomy were damaged more severely as compared with control or thymalin-treated animals. In thymectomized rats treated with thymalin, the absolute content of medium-sized and big lymphocytes in peripheral blood was found to be lower, the content of small lymphocytes being unchanged throughout all observation periods. The time course of migration activity (spontaneous and in response to PPD) in rats treated with thymalin corresponded with the time course in controls in contrast to thymectomized rats which did not receive the treatment. The results indicate that tuberculosis severity depends on the degree of immunodeficiency and that the functional properties of immunocompetent cells may be corrected with thymalin.