[Studies of radiosensitization of hyperthermia and hypertonic treatment in HEp-2 cells].

This paper presents the effects of hyperthermia, irradiation and post-irradiation treated by hypertonic solution on HEp-2 cells, alone or combined in vitro. The results showed that when the radiation treatment with hyperthermia at 44 degrees C 15', the latter had no directly killing effect on cells, a significant radiosensitization was found. The dose response curve showed that the Dq which represents sublethal damage was decreased to 4-5 times (1.49 Gy/0.31 Gy). However, the dose of D(o) which represents potentially lethal damage had almost not changed. When cells were treated with hypertonic solution (0.3 mol/L NaCl) postirradiation, or treated by combination of hyperthermia, irradiation, and hypertonic solution, the results were near the same, as compared with combination with hyperthermia alone. It is concluded that the radiosensitization is induced by hyperthermia which can inhibit the repair of the radio-induced DNA damage by heating.