[The first cycle of DNA replication in parthenogenetic mouse embryos].

Dynamics of the first cell cycle in parthenogenetic mouse embryos derived from ethanol-activated eggs was studied using 3H-thymidine. DNA synthesis starts within 5 h and is terminated within 10 h after activation: it lasts ca. 6 h.

[The first cycle of DNA replication in mouse embryogenesis studied by microinjections of 3H-thymidine into the cytoplasm of fertilized ova].

H-thymidine was injected into cytoplasm of the eggs taken at different intervals after fertilization and the eggs were fixed immediately thereafter. DNA synthesis was shown to begin in pronuclei when they are still in the marginal zones of cytoplasm, immediately after their formation. S-phase lasts 5-6 h in every pronucleus and is terminated at 1-2 h before the first cleavage division when the pronuclei are closely approached and located in the center of cytoplasm.

[Implantation and deciduation process after the action of the antihistamine preparation diprazin in early rat embryogenesis].

A histological and historadioautographical analysis of the uterine endometrium decidual tissue on the 5th, 6th, 7th and 8th days of pregnancy has shown that diprasin affects the processes of proliferation and differentiation of decidual cells, thus delaying the embryo's implantation. Deviations in the zonal division of decidual cells by their mitotic activity were found at all stages studied. The second (from the embryo) zone and mesometral part of deciduoma which are cambial regions proved to be the most sensitive.

[Radioautographic and cytofluorimetric analysis of DNA synthesis during the pre-implantation period of rat and mouse embryonic development].

The patterns of DNA synthesis and kinetics of cell population in the rat and mouse embryos were studied by means of 3H-thymidine autoradiography and cytofluorimetry. The rat and mouse embryos during the period of cleavage consist of a heterogenous population of blastomeres. At all the stages under study, all phases of the cell cycle occur in the blastomeres: G1, S, G2 and mitosis.

[DNA synthesis in the antimesometrial and mesometrial regions of rat decidual tissue].

DNA synthesis in the decidual tissue of rats on the 9-10th day of pregnancy has been studied in intact rats and under the effect of chloridin by means of radioautography and biochemical methods. The decidual cells of antimesometral and mesometral regions were shown to differ both by morphological features and intensity of 3H-thymidine utilization and activity of thymidylate synthetase and thymidine kinase. Under the conditions of the block of dihydropholate reductase, differences between the antimesometral and mesometral regions of deciduoma manifest themselves still more markedly.