[The cytogenetic effect of ultralow doses of nitrosomethylurea]

Cytogenetic effects of ultra low doses of nitrosomethylurea in the range 10(-12)-10(-17) mol/(kg x day) on the chromosome structure were studied in the Ehrlich tumor and leucosis L-12110 cells. It was shown that nitrosomethylurea at an ultra low dose of 10(-17) mol/(kg x day) induces chromosome aberrations in the cells of the both studied tumors after a single and multiple injections to random bred and linear animals. The recorded effect suggests that with the decrease of therapeutic dose by 13 orders of magnitude the cytogenetic activity of the drug decreases by no more than one order of magnitude.