Some EPR Signals in Tumour Tissue

Abstract

Summary.-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.

Anticancer effects of 6-o-palmitoyl-ascorbate combined with a capacitive-resistive electric transfer hyperthermic apparatus as compared with ascorbate in relation to ascorbyl radical generation

“…The characteristic doublet signal of AscR (Dodd 1973) was detected. AscR showed an asymmetric doublet signal with a line width of 0.18 mT centered at g = 2.007.…”

Electron spin resonance study of changes during the development of a mouse myeloid leukaemia. II. The ascorbyl radical

“…More recent studies have shown that this radical is present in a wide variety of malignant tissues at a higher concentration than in the corresponding normal tissues (Dodd, 1973). Consequently a systematic study has been made of the changes in the ascorbyl radical concentration occurring in the blood, spleen and liver during a murine myeloid leukaemia.…”

The nature of the ESR signal in lyophilized tissue and its relevance to malignancy

“…The nature of each of these and their probable mode of formation is discussed below. The narrow doublet signal, seen only in unfrozen samples of tissue has previously been assigned to the ascorbyl radical (Dodd, 1973). This signal, although not detected in normal muscle, is readily observed in implanted tumours (Dodd & Silcock, 1976) and implants of normal tissue (Dodd & Silcock, 1980).…”

“…Results 9 GHz ESR of tissues The characteristic doublet signal (Figure 1) of the ascorbyl radical (Dodd, 1973) was detected at room temperature in the samples of implanted muscle, but was not detected in normal muscle. However, when removed and sampled under anoxic conditions, the implanted muscle showed no signal until exposed to air.…”