[Changes in distribution of cell cycle phases and DNA content in HeLa S3 cells after irradiation and heat treatment].

The effects of irradiation and hyperthermia on the distribution in various phases and DNA content of HeLa S3 cells were analyzed by flow cytometry and an image analysis instrument. A marked increase in DNA content from 6.718 to 9.614(AU) in HeLa S3 cells after 6 Gy irradiation was seen to correspond with the changes in the distribution of various phases in G2 + M, from 22%-52%. Meanwhile, the surviving fraction of HeLa S3 cells after 6 Gy irradiation was less than 1%. However, after heating at 44 degrees C for 10 min, the amount of cells in G2 + M% increased from 22.5% to 52.5% and the surviving fraction after hyperthermia was less than 2.65%. The changes in distribution of various phases after Ir-192 irradiation were similar to those seen after X-ray irradiation. The delay of G2 + M phase after treatment with 8 Gy plus heating at 44 degrees C for 7 min in HeLa S3 cells was similar to that seen in the case of treatment with 8 Gy alone. As the surviving fraction accompanying the G2 + M delay after irradiation plus heat treatment was very low, we suggest that the changes of distribution in various phases of HeLa S3 cells after treatment might be used as a rapid indicator of serious injury.