[Relation between sister chromatid exchange and duration of human cell treatment with ethyleneimine derivatives].

The sister chromatid exchange (SCE) induction by various concentrations of thiophosphamide and dipin was studied depending on the exposure time to mutagens. There is a linear relationship between the number of SCE and the increase in the concentration and exposure time regardless of the chemical structure of mutagens. The dose dependence (the product of the concentration magnitude by exposure) is also depictable by the linear law. A sudden leap of the number of SCE was observed during the transition from control to minimal exposure.