Nuclear Spin Relaxation in Solutions Prepared from Normal and Tumor Hepatic Tissues: Brief Communication 2

Abstract

Water proton nuclear spin relaxation times were investigated at two frequencies (10.7 and 100 MHz) in solutions prepared from Dunning hepatomas (LC-18) and normal Iivers of F344 rats. The solutions (saps) were prepared by homogenization of the tissue without the addition of water or chemieals, followed by two centrifugations. The water proton spin-lattice and spin-spin relaxation times (T1 and T2, respectively) were longer in the tumor sap than in the Iiver sap. The T1/T2 ratio was higher than that for pure water, and the T1 values were higher at the higher frequency. A rough correlation with significant scatter was found between T1−1 and F/(1−F), where F is grams protein/grams solution. Precipitation of protein with trichloroacetic acid yielded solutions that showed higher T1 values when prepared from tumor sap than from Iiver sap. Glycogen concentrations were much higher in the deproteinated liver saps than in deproteinated hepatoma saps. Dialysis of fresh sap against butter for 4 hours produced no change in T1. Addition of the reducing agent sodium dithionite produced no change in T1. It was concluded that water-protein and water-glycogen interactions are the predominant mechanism for the shortening of sap relaxation times relative to that of distilled water. The higher concentrations of protein and glycogen in liver sap compared to hepatoma sap were the likely cause of the liver sap T1 values being shorter than those of hepatoma sap. No evidence of a significant paramagnetic speeies ettect on sap T1 was found.