[en] The authors examined initial yields and kinetics of rejoining of interphase chromosome breaks in irradiated plateau-phase Chinese hamster ovary cells by means of premature chromosome condensation (PCC) using either Sendai virus or polyethylene glycol (PEG) as fusogens. They found a yield of 2.2 chromosome breaks/cell/Gy independently of the method used to induce PCC. Rejoining of interphase chromosome breaks also proceeded with identical kinetics in cells fused using either Sendai virus or PEG. In an additional set of experiments they compared the kinetics of rejoining of interphase chromosome breaks in cells synchronized in G₁ phase by elutriation to that measured in plateau-phase cells, using either Sendai virus or PEG as fusogens. (Author)