Dodd N J
Br J Cancer. 1973 Sep;28(3):257-62. doi: 10.1038/bjc.1973.145.
Normal and tumour tissues from rats, blood from normal and tumour bearing rats, and normal human blood were examined using the electron paramagnetic resonance (epr) technique. At low temperature a triplet epr signal, which is known to be produced by a NO-haemoprotein complex, was detected in some tumour samples and in decaying normal liver. At room temperature all of the tumour samples examined gave a doublet signal. This signal was also detected in blood but not in other normal tissues. The signal has a g value of 2·0054 ± 0·0002 and a hyperfine splitting of 1·80 ± 0·05 G and is assigned to the ascorbyl free radical. Model experiments suggest that the appearance of detectable concentrations of this radical result from a disturbance of the normal state of the ascorbic acid, dehydroascorbic acid redox system. It was verified that cell division is not responsible for the ascorbyl radical although autolysis may be involved. A possible relationship between the formation of ascorbyl radicals and other paramagnetic species in tumours is discussed.
使用电子顺磁共振（EPR）技术对大鼠的正常组织和肿瘤组织、荷瘤大鼠和正常大鼠的血液以及正常人的血液进行了检测。在低温下，在一些肿瘤样本和正在衰变的正常肝脏中检测到一种三重态EPR信号，已知该信号由NO-血红蛋白复合物产生。在室温下，所有检测的肿瘤样本都给出了一个二重态信号。在血液中也检测到了该信号，但在其他正常组织中未检测到。该信号的g值为2.0054±0.0002，超精细分裂为1.80±0.05G，被归因于抗坏血酸自由基。模型实验表明，这种自由基可检测浓度的出现是由于抗坏血酸、脱氢抗坏血酸氧化还原系统的正常状态受到干扰所致。已证实细胞分裂与抗坏血酸自由基的产生无关，尽管自溶可能与之有关。讨论了肿瘤中抗坏血酸自由基的形成与其他顺磁物质之间的可能关系。
