Nielsen O S, Overgaard J
Int J Hyperthermia. 1985 Apr-Jun;1(2):193-203. doi: 10.3109/02656738509029285.
The development of thermotolerance in L1A2 cells in vitro was investigated after fractionated hyperthermia at 42 degrees C. A single pretreatment of 90 min at 42 degrees C resulted in maximal thermotolerance at a 10 h fractionation interval with a thermotolerance ratio (TTR) of approximately 4.5. Thermotolerance was maintained at this level if the cells were exposed to 1-3 additional 90 min pretreatments separated by 10 h intervals. At a 6 h fractionation interval, where thermotolerance was still developing, additional 90 min pretreatments raised the level of thermotolerance to the level induced by the 10 h interval; the TTR increased from 2.1 to 4.5. Intervals of 20 and 24 h, at which there was decay but not complete disappearance of thermotolerance, did not induce such a build-up, and the TTR remained constant at 2.5 and 1.6, respectively. With 2 h fractionation intervals, where a single pretreatment did not induce thermotolerance, no thermotolerance was induced by additional pretreatments. With a shorter preheating time (e.g. 45 min at 42 degrees C) administration of a single pretreatment induced maximal thermotolerance after 6 h with a TTR of 3.0; additional 45 min pretreatments separated by 6 h intervals maintained this level. The thermotolerance induced by multifractioned hyperthermia as described above decayed in a similar way to that of cells exposed to a single pretreatment.
在42℃分次热疗后，对体外培养的L1A2细胞耐热性的发展进行了研究。在42℃进行90分钟的单次预处理，在10小时的分次间隔时产生最大耐热性，耐热比（TTR）约为4.5。如果细胞再接受1 - 3次间隔10小时的90分钟预处理，耐热性可维持在该水平。在6小时的分次间隔时，耐热性仍在发展，额外的90分钟预处理可将耐热性提高到10小时间隔诱导的水平；TTR从2.1增加到4.5。20小时和24小时的间隔时，耐热性虽有衰减但未完全消失，不会诱导这种耐热性的增强，TTR分别保持在2.5和1.6不变。在2小时的分次间隔时，单次预处理不会诱导耐热性，额外的预处理也不会诱导耐热性。预热时间较短（如42℃下45分钟）时，单次预处理在6小时后诱导出最大耐热性，TTR为3.0；间隔6小时进行额外的45分钟预处理可维持该水平。上述分次热疗诱导的耐热性与单次预处理细胞的耐热性衰减方式相似。
