Gutierrez P L, Swartz H M, Wilkinson E J
Br J Cancer. 1979 Mar;39(3):330-6. doi: 10.1038/bjc.1979.57.
Electron spin resonance (ESR) studies were made on frozen samples of 7,12 dimethylbenzanthracene (DMBA)-induced rat breast tumours both before and after lyophilization. The primary purpose of these studies was to determine the relationship between ESR spectra under these two conditions and thereby hopefully resolve an apparent conflict as to the experimental findings and clinical implications of these findings. In contrast to the other system (Walker 256 carcinosarcoma) which we studied by a similar method, in the DMBA-induced tumours we found a close parallel between the ESR spectra before and after lyophilization. In both cases free-radical levels were elevated about two-fold in all tumours and showed little dependence on the age of the tumour. Studies of blood and liver before the development of tumours showed no change in free radicals levels in either nonlyophilized or lyophilized samples. In animals with tumours, the level of free radicals in the liver increased approximately 17%. Manganese (2+) levels were increased in breast tumours but the changes did not closely follow those of free radicals and were much more variable in the lyophilized samples. We conclude that: (1) there seems to be no general relationship between ESR spectra of tumours before and after lyophilization; (2) there appears to be no general pattern of ESR changes in lyophilized samples of tumours.
对7,12 - 二甲基苯并蒽（DMBA）诱导的大鼠乳腺肿瘤的冷冻样本在冻干前后进行了电子自旋共振（ESR）研究。这些研究的主要目的是确定这两种条件下ESR光谱之间的关系，从而有望解决关于这些研究结果的实验发现和临床意义的明显冲突。与我们用类似方法研究的其他系统（Walker 256癌肉瘤）不同，在DMBA诱导的肿瘤中，我们发现冻干前后的ESR光谱非常相似。在这两种情况下，所有肿瘤中的自由基水平均升高了约两倍，并且几乎不依赖于肿瘤的年龄。在肿瘤发生前对血液和肝脏的研究表明，未冻干和冻干样本中的自由基水平均无变化。在患有肿瘤的动物中，肝脏中的自由基水平增加了约17%。乳腺肿瘤中的锰（2+）水平升高，但变化与自由基的变化并不密切相关，并且在冻干样本中变化更大。我们得出以下结论：（1）肿瘤冻干前后的ESR光谱之间似乎没有普遍关系；（2）肿瘤冻干样本中ESR变化似乎没有普遍模式。
