Cytokinetic analysis at various ages of an ascites tumor after radiation

A cytokinetic analysis has been made of 5-day and of 10-day old murine 6C3HED ascites lymphosarcoma (Gardner) by using a growth curve, percentage of labeled mitoses curves, and continuous labeling curves. The doubling time increased from 36 h in the proliferative phase of growth to 252h in the stationary phase. The slowing down of the growth rate was due to prolongation of the cell cycle time, with greatest extension in G1 and increased cell loss. The measurement of the kinetic parameters made immediately after irradiation with a whole-body single dose of 3 Gy (300 rad) showed an increase in duration of the cell cycle in the 5-day-old tumor, while in the 10-day-old tumor the cell cycle time was decreased due to reduce length in the G1 phase.