Lindegaard J C, Overgaard J
Danish Cancer Society, Department of Experimental Clinical Oncology, Aarhus, Denmark.
Int J Hyperthermia. 1990 May-Jun;6(3):607-17. doi: 10.3109/02656739009140957.
The effect of step-down heating (SDH), consisting of an initial sensitizing treatment (ST) performed at either 44.5 degrees C or 43.5 degrees C followed by a lower temperature test treatment (TT), was investigated in a C3H mammary carcinoma in vivo. A linear relationship between heating time and tumour growth delay was observed for all temperature combinations applied. At a given TT temperature, SDH increased the slope of the dose-response curve compared to the curve for tumours, single-heated without an initial ST. The slope of the SDH curves increased asymptotically towards a plateau value as the ST time at 44.5 degrees C was increased. The time-temperature relationship for single heating was described by a biphasic Arrhenius curve with activation energies of 1361 +/- 34 and 666 +/- 54 kJ/mol below and above an inflection point at 42.5 degrees C, respectively. For SDH, the Arrhenius curve gradually became straight with increasing ST time, and the activation energy saturated at a value of 425 +/- 25 kJ/mol. The reduction of the activation energy at an ST temperature of 43.5 degrees C was due rather to the extent of ST heat damage than to the ST time or temperature used. These results may be relevant for calculations of thermal doses, since even a short temperature peak (e.g. 44.5 degrees C/5 min) significantly changed the time-temperature relationship.
在C3H乳腺癌体内研究了递减加热（SDH）的效果，它由在44.5℃或43.5℃进行的初始致敏处理（ST），随后进行较低温度的测试处理（TT）组成。对于所应用的所有温度组合，观察到加热时间与肿瘤生长延迟之间存在线性关系。在给定的TT温度下，与未经初始ST的单次加热肿瘤的曲线相比，SDH增加了剂量反应曲线的斜率。随着44.5℃下ST时间的增加，SDH曲线的斜率渐近地增加至平台值。单次加热的时间 - 温度关系由双相阿伦尼乌斯曲线描述，在42.5℃拐点以下和以上的活化能分别为1361±34和666±54kJ/mol。对于SDH，随着ST时间增加，阿伦尼乌斯曲线逐渐变直，活化能饱和在425±25kJ/mol的值。在43.5℃的ST温度下活化能的降低更多是由于ST热损伤的程度，而不是所使用的ST时间或温度。这些结果可能与热剂量的计算有关，因为即使是短暂的温度峰值（例如44.5℃/5分钟）也会显著改变时间 - 温度关系。
