THE RESEARCH OF THE DIFFERENTIAL HYPOTHERMIA THERAPY FOR BRAIN TUMORS

不同程度低温对培养脑肿瘤细胞的影响采用体外培养的大鼠胶质瘤细胞系（C6），通过集落形成实验研究了热药联合应用的作用。用亚硝基脲衍生物ACNU在不同的热处理条件下处理细胞，43 ℃处理1或2 h后，细胞存活率分别降至未处理细胞的76%和28%。5 μ g/ml ACNU组细胞存活率分别为55%和19%，20 μ g/ml ACNU组细胞存活率分别为3%和0.5%。以上结果表明，高体温可显著增强ACNU的杀瘤作用，提示ACNU与亚低温协同作用可获得更强的杀瘤效果.采用立体定向法将VX 2肿瘤细胞移植于兔脑内建立实验性脑肿瘤模型。另一方面，为了研究915 MHz微波辐射下正常脑组织的热分布，比较了915 MHz和2.450MHz微波辐射下的热分布。915 MHz微波辐射比2.450MHz微波辐射获得更均匀和相对更深的加热。然而，目前用于915 MHz辐射的发生器，其最大发生功率为45 W，在30 ℃的全身低温下，似乎很难保持大脑超过37 ℃，因此，有必要加强发生器。在微波天线和物体之间填充氧化铝比填充空气间隙可以获得更好的加热效果。在30 ℃全身低温下连续加热5小时后，肉眼和显微镜下均未见病理改变。为了评价差异低温的杀瘤作用，建立了Rous肉瘤病毒诱导的成年猴脑肿瘤模型

Effect of Differential Hypothemia on Cultured Brain Tumor Cells1. The effects of combined use of heat with drug were studied by colony forming assay, using a cultured rat glioma cell line (C6). The cells were treated with a nitrosourea derivative ACNU in different thermal conditions.After treament of 43ﾟC for 1 or 2 hours, the surviving fraction reduced to 76% or 28% of non-treatment cells. While with 5mug/ml ACNU,the surviving fraction reduced to 55% or 19% and with 20mug/ml ACNU, 3% or 0.5%, respectively. These results proved that hyperthermialead to marked increase of cytocidal effect of ACNU and suggested the synergestic activity of ACNU and differential hypothermia to achieve greater tumoricidal effect.2. An experimental brain tumor model was established with VX2 tumor cells stereotactically transplanted in the rabbit brain. On the other hand, to investigate the thermal distribution in the normal brain under 915MHz microwave irradiation, the thermal distribution under 915MHz and 2.450MHz microwave irradiation were compared. More uniform and relatively deeper heeting was achieved with 915MHz microwave irradiation than with 2.450MHz. However, it seemed quite difficult for the generator presently used for the 915MHz irradiation, whose maximal generating power is 45W,to keep the brain over 37ﾟC under the systemic hypothermia of 30ﾟC.Therefore, reinforcement of the generator seemed to be necessary. Furthrmore, further heating effect could achieved to fill aluminium oxide between the microwave antenna and the object than air gap. No macro-or microscopically pathologic change was seen after 5-hour continuous heating of the brain under systemic hypothermia of 30ﾟC.3. To evaluate the tumoricidal effect of differential hypothermia, a Rous Sarcoma virus-induced brain tumor model was established in adult monkeys