Electron spin resonance study of changes during development of solid yoshida tumour. II. Paramagnetic metal ions.

Electron spin resonance (ESR) spectroscopy was used to examine changes in the concentration of paramagnetic metal ions in Yoshida tumours carried by female Wistar rats. Blood, spleen and lymph nodes from these animals were also examined by ESR. A decrease in the concentration of a paramagnetic species associated with mitochondrial activity, and marked increases in those thought to be associated with inflammatory or immune reactions and cell lysis, were observed in the tumours within one day of implantation. During development of the tumour, and during its regression after treatment with methylene dimethane sulphonate (MDMS), further changes were observed in the concentration of the species. These were dependent on the region of the tumour examined. In blood, development of the tumour produced an increase in ceruloplasmin and a decrease in iron-transferrin. An increase in spleen weight, as the tumour developed, was accompanied by a small decrease in the concentration of species with g-values of 6-0 and 4-3, which was reversed on regression of the treated tumour. The presence of metastases in the regional lymph nodes produced distinguishable changes in the ESR spectra.