[Relationship between the cytogenetic effect of different concentrations of thiophosphamide and phosphemide and the duration of their contact with human lymphocytes].

The effect of thiophosphamide at conccentrations of 10, 20 and 30 mcg/ml and phosphamide at concentrations of 35 and 50 mck/ml on human lymphocyte chromosomes at different time of the contact was investigated. The experiments were carried out at GO phase (before adding FGA) at 37 degrees C from 10 to 240 minutes. The fixation was made within 58th hour. A mathematical model, satisfactory describing experimental data on the reaction of mutagen-chromosome interaction during the time of exposition, is suggested. According to this model, the following equation are obtained: rho = (1 - e-(alpha+Kt))2; chi = (see article), where rho is a portion of aberrant cells, chi is the average number of breaks per cell, t is the time of exposition of mutagens with cells, alpha and K are coefficients. Breaks induced by thiophosphamide and phosphamide are distributed among cells according to geometrical parameter under any experimental conditions. The portion of chromatid breaks did not change at any exposition time for both mutagens and remained on the level of 76,53%. The proportion of symmetric and asymmetric exchanges under different experimental conditions did not differe from 1 : 1. The prabability of the formation of complete exchanges in the case of the action of thiophosphamide was higher than in the case of phesphamide.