Effects of hyperthermia on survival and progression of Chinese hamster ovary cells.

作者：Stephen A. Sapareto, Larry E. Hopwood, William C. Dewey, M.R. Raju, Joe W. Gray · 发表于：PubMed · 年份：1978 · 被引用次数：248 · 研究领域：Effects of Radiation Exposure、Ultrasound and Hyperthermia Applications、Radiation Therapy and Dosimetry

Abstract In general, the survival of Chinese hamster ovary cells exposed to hyperthermic temperatures of 42.5–46.0° decreases exponentially as a function of duration of heat exposure in a manner quite similar to survival as a function of radiation dose. The data indicate that above 43° a 1° change in temperature requires a 2-fold change in time to achieve the same degree of killing, whereas below 43° the same 2-fold change in time requires only a 0.5° change in temperature for the same effect. An Arrhenius-type plot of the logarithm of the rate of killing as a function of reciprocal temperature exhibits linearity with a change in slope at 43°. This change in slope suggests either a change in the mechanism of cell killing below this temperature or a manifestation of thermal tolerance that is readily observed when the duration of heating exceeds 4 to 5 hr. Thermotolerance to 45.5°, as evidenced by a 3- to 4-fold increase in D0, is observed in synchronous G1 cells exposed to heat 20 hr after an initial heat dose. This thermotolerance develops, although no progression of cells into S phase occurs during this period. In addition, thermotolerance develops in both asynchronous and synchronous G1 cells exposed to single heat doses between 41.5 and 42.5° for periods exceeding 4 to 5 hr, i.e., survival decreases exponentially as a function of duration of heating up to 4 to 5 hr, after which survival decreases very little. At 42.0–42.5°, survival is extremely sensitive to changes in tem...