Gutierrez P L, Swartz H M
Br J Cancer. 1979 Jan;39(1):24-34. doi: 10.1038/bjc.1979.4.
Samples of Walker 256 carcinoma grown in muscles of Sprague-Dawley rats were studied at low temperatures before and after lyophilization. The effects of lyophilization on the ESR spectra were different for tumours and normal muscle. Prior to lyophilization of a tumour sample, there was a decrease in free radicals, while after the lyophilization, there was an "increase". The "increase" was due to the lyophilized tumour having a narrower line, producing a greater peak-peak height measurement than in muscle, without an increase in the total number of spins. Exposure of lyophilized samples to air produced an increase in the intensity of the spectra and a change in line shape; also these effects differed for tumour and muscle. Mn++ levels were lower in tumour than in muscle, a difference eliminated by lyophilization. Poor growth conditions in tumours increased the occurrence of ESR spectra due to NO complexes with both heme and non-heme iron proteins. These results may help to resolve the principal controversies about experimental findings in ESR of tumours. At least part of the signals seen after lyophilization do not reflect free radicals in vivo. The signals after lyophilization reflect biochemical differences between tumour and muscle; spectroscopic data indicate that it is feasible to determine the molecular basis of these differences.
对生长在斯普拉格-道利大鼠肌肉中的沃克256癌样本在冻干前后进行了低温研究。冻干对肿瘤和正常肌肉的电子顺磁共振（ESR）光谱的影响不同。在肿瘤样本冻干之前，自由基减少，而冻干后则出现“增加”。这种“增加”是由于冻干后的肿瘤谱线变窄，导致峰-峰高度测量值比肌肉中的更大，而自旋总数并未增加。将冻干样本暴露于空气中会使光谱强度增加且谱线形状发生变化；而且这些影响在肿瘤和肌肉中也有所不同。肿瘤中的锰离子水平低于肌肉，冻干可消除这种差异。肿瘤中恶劣的生长条件会增加因一氧化氮与血红素和非血红素铁蛋白形成复合物而产生的ESR光谱。这些结果可能有助于解决关于肿瘤ESR实验结果的主要争议。至少部分冻干后看到的信号并不反映体内的自由基。冻干后的信号反映了肿瘤和肌肉之间的生化差异；光谱数据表明确定这些差异的分子基础是可行的。
