Law M P, Ahier R G, Somaia S
MRC Cyclotron Unit, Hammersmith Hospital, London, U.K.
Int J Hyperthermia. 1987 Sep-Oct;3(5):433-9. doi: 10.3109/02656738709140413.
The induction of thermotolerance by fractionated hyperthermia was investigated in the mouse ear. Ears were heated at 43.5 degrees C by immersion in water. One to ten treatments of 20 min were followed by test treatments. Thermotolerance was assessed as the increase in the duration of the test treatment required for a thermal response in 50 per cent of the ears (NT50). A single treatment induced thermotolerance which reached a maximum at 24 h when the NT50 was increased by a factor of 2.4. The same maximum was observed after each fractionated treatment used in the present study. The time course of development, however, depended on the interval between fractions. (1) When the interval was too short to allow development of thermotolerance after a single fraction (4 h), thermotolerance was not induced during fractionated treatment but it developed during the first 24 h after treatment. (2) When the interval between fractions allowed the maximal development of thermotolerance (24 h), this maximum was maintained during fractionated treatment and persisted for 24 h after treatment. (3) When the interval allowed some decay of thermotolerance (72 or 168 h) there was a further increase to maximal thermotolerance after each fraction. The decay of thermotolerance from the maximum did not depend on the interval between fractions. These results indicate that the degree of thermotolerance may fluctuate during fractionated hyperthermia.
在小鼠耳部研究了分次热疗诱导热耐受的情况。将耳部浸入水中，在43.5摄氏度下加热。进行1至10次每次20分钟的治疗后进行测试治疗。热耐受通过50%的耳部出现热反应所需的测试治疗持续时间的增加来评估（NT50）。单次治疗可诱导热耐受，在24小时时达到最大值，此时NT50增加了2.4倍。本研究中使用的每次分次治疗后均观察到相同的最大值。然而，热耐受发展的时间进程取决于分次之间的间隔。（1）当间隔过短，以至于单次分次治疗后无法形成热耐受（4小时）时，分次治疗期间不会诱导热耐受，但在治疗后的头24小时内会形成热耐受。（2）当分次之间的间隔允许热耐受充分发展（24小时）时，在分次治疗期间会维持这一最大值，并在治疗后持续24小时。（3）当间隔导致热耐受出现一定程度的消退（72或168小时）时，每次分次后热耐受会进一步增加至最大值。热耐受从最大值开始的消退并不取决于分次之间的间隔。这些结果表明，在分次热疗期间热耐受程度可能会波动。
