[Effect of single and fractionated gamma irradiation on the growth and development in culture of Tr. Foetus]. / Vliinaie na ednokratnoto i fraktsionirano obluchvane s gama-luchi vurkhu rastezha i razvitieto v kulturite na Tr. foetus.

Studied was the effect of gamma-treatment on the growth and development of Tr. foetus in cultures. The experiments were carried out with two strains (180 and 2548) supplied from the Academy of Sciences, Tallin, ESSR (USSR). Irradiation was performed by means of increasing rates of gamma treatment (from 1000 to 1500000 rad) applied either once or twice at equal portions and intervals of 1 and 3 or 24 hours. It was found that the higher the intensity of treatment the higher the biologic effect of gamma rays as judged by the inhibition of both the growth and the development of Trichomonas, by the changes in the morphology and physiology of this species, and by the lethal effect. The fractionated treatment at two rates coinciding with one or two consecutive mitotic cycles produced a stronger inhibitory effect than the single treatment at the same rate. In case the two fractions of treatment did not coincide with any of the mitotic cycles of division their effect was similar to that of the single treatment.