RADIATION-INJURY OF CHROMOSOMES DURING CELL-CYCLE INVIVO

The duration of the cell cycle and its phases after the correction of proliferating cell fraction of bone marrow cell population of Chinese hamster was established. The duration of the cell cycle is 9.5 h, the duration of G1 phase 1.9 h, of S phase 6.0 h, of G2 phase 0.7 h and of M phase 0.9 h. The value of proliferating cell fraction (f) is 0.67. Proliferation kinetics of asynchronous cell population was illustrated by means of the kinetic model. On the basis of proliferation kinetics chromosomal changes from the viewpoint of chromosome and chromatid type breaks were analyzed in relation to the phases of the cell cycle. The mutagenic effect on chromosomal level may be studied during the cell cycle phases not only in synchronous populations but also in asynchronous cell populations in vivo. The injury or repair of chromosomes and DNA of proliferating cell populations should be studied simultaneously with proliferation kinetics.