Recovery kinetics from radiation and hyperthermia damage to cultured Chinese hamster V79 cells

The recovery kinetics from the damage resulting from combination treatments of X-irradiation and 42 degrees and 44 degrees C hyperthermia were analyzed in Chinese hamster V79 cells. The survival of cells attained to the additive level, when either 42 degrees C hyperthermia or 42 degrees C hyperthermia and X-irradiation was given as the first treatment, followed by a 3- to 4-hour interval at 37 degrees C with combined treatments of X-irradiation and 42 degrees - 44 degrees C sequential hyperthermia. The survival of cells attained to the additive level when X-irradiation or 44 degrees C hyperthermia, or both, were given as the first treatment followed by a 5- to 7-hour interval in the combined treatments of X-irradiation and 44 degrees - 42 degrees C sequence. However, when the combined hyperthermia of 44 degrees - 42 degrees C sequence was given as the first treatment, the survival of cells did not attain the additive level within a 24-hour interval at 37 degrees C. From these results, researchers believe the damage induced by the combined hyperthermia of the 44 degrees - 42 degrees C sequence was retained partially in the cells during at least a 24-hour interval at 37 degrees C and may interact synergistically with the damage by the subsequent X-irradiation