[Chromosome aberrations in peripheral blood lymphocytes of cosmonauts after long-term space flight]

The incidence and the types of chromosome aberrations in lymphocytes of the peripheral blood in culture in vivo were studied in a cosmonaut following 14-day space flight (SF) and in three cosmonauts on completion of 177- and 194-day SF. After prolonged SF each cosmonaut displayed an increase in the number of aberrant cells and the incidence of chromosome damages. The rise in the number of aberrant cells was 2-3-fold comparing with the preflight level and 3-8-fold comparing with the number of aberrant mitoses in young subjects. Emergence of dicentric and centric rings was characteristic for two cosmonauts and their increased number in a third cosmonaut. These defects in the chromosome apparatus in cells are similar to the damages in chromosomes resulting from the exposure of lymphocyte culture in vitro to accelerated charged particles and are assumed to predominantly originate in the exposure to GCR heavy nuclei.