[Effect of space flight factors on bone marrow cells in the rat]. / Deistvie faktorov kosmicheskogo poleta na kostnomozgovye kletki krys.

The effect of space flight factors, weightlessness in particular, on the genetic structures of bone marrow cells of rats flown for 18.5 days on Cosmos-1129 was investigated. Chromosome aberrations were measured on postflight days 6 and 25. The frequency of unstable chromosome aberrations was similar in the flight, synchronous and vivarium rats. Karyotyping of metaphase plates revealed chromosome aberrations in the flight and synchronous rats. Exposure to weightlessness did not influence the mutagenic effect in bone marrow cells of the rats.

[Dominant lethality and translocations in the sex cells of male rats under low-intensity gamma irradiation]. / Dominantnaia letal'nost' i translokatsii v polovykh kletkakh samtsov krys pri gamma-obluchenii nizkoi moshchnosti.

Adult male rats were given 1300 rad of chronic gamma-irradiation (0.08 rad/min) Dominant lethal rates were found to be high (ranging from 48 to 75%) in irradiated postmeiotic cells and clearly lower (6.8%) in spermatogonia. The chromosome aberration (reciprocal translocation) yields observed with 1300 rad chronic irradiation were comparatively low, averaging 1.6%. Spermatogonia irradiation at low dose rate resulted in a smaller effect as compared to the genetic effects of a single acute exposure.

Mouse oocyte dominant-lethal response to chronic gamma irradiation.

Adult mouse females were given 500 rad of chronic gamma rays at 0.01 rad/min and mated to unirradiated males during seven successive weeks to score the frequency of dominant-lethal mutations. Total dominant lethality was increased for any of the weeks post-radiation. Post-implantation dominant lethal yields were low, ranging from 2.5 to 6.1% for individual weeks p.r.