Electron spin resonance spectra of chicken hepatoma and liver tissue

When studied by electron spin resonance (ESR) (Swartz et al., 1972), tumorous tissues differ from their normal equivalents in the following aspects: 1. In tumourous tissues the signal measured in the vicinity of the g=2 region of the spectrum is of a smaller amplitude or completely absent (Commoner et al., 1954; Commoner, Ternberg, 1961; Mallard, Kent, 1964; Dodd, 1973). 2. Signals attributed to certain paramagnetic metal ions are also decreased (Nebert and Mason, 1963; Swartz et al., 1973). New lines may exceptionally appear, too (Mallard, Kent, 1966). So far mostly human and mammalian tumours (hepatoma and liver tissue) induced by carcinogens have been studied. The aim of the present work was to extend these observations to a fowl tumour of viral origin.