Investigation of bound water in frozen precancerous rat liver tissue by proton NMR.

The proton NMR spin lattice relaxation times of bound water (T1b) were studied on frozen rat liver samples during the precancerous step of cancer induction by diethylnitrosamine. Two components of the T1b were found, which show a different temperature dependence of their relative magnetization. Four different steps were identified during the experimental cancer induction according to 1H NMR findings, while only three were distinguished after histological examination. The results point to the influence of cross-relaxation and corroborate previous reports on differences observed between the heat capacity of normal and tumorous tissues.