The Effect of Cold Storage of Mitotic Cells on Hyperthermic Killing and Hyperthermic Radiosensitization during G 1 and S

Mitotic cells were either plated directly into flasks in a 37/sup 0/C warm room or cooled and maintained at 1-2/sup 0/C for 3 hr prior to plating. The cold storage of mitotic cells delayed progression into the G/sub 1/ phase by 20-60 min and into S phase by 90-110 min. Cold storage also increased sensitivity to hyperthermic killing when the cells were heated during G/sub 1/ or S phase; i.e., a two- to threefold decrease in survival for 17 min of heating at 45.5/sup 0/C. However, cold storage did not increase hyperthermic radiosensitization during G/sub 1/.