[Cells with fragmented nuclei in ascites hepatoma 22A and their participation in proliferation].

The number of cells with fragmented nuclei (FN) (mainly, multilobate) increased with aging of ascites hepatoma 22A (AH22A) as follows: 15 +/- 9.3% in the 6-day AH22A, 196 +/- 53% in the 14-day tumor and 453 +/- 51% in the delayed (18-day) AH22A. The basic way of FN formation was amitotic. About 150 and 170% of cells with FN in the 14- and 18-day AH22A were at the reversible resting R1 stage (or at the very long G1 period, more than 4 days). The rest of the cells, 50 and 230%, respectively, quit the mitotic cycle irreversibly and apparently undergo the involution that is faster during passage-stimulated division.