Radioautographic Solubility Studies of I131 and P32 in Frozen-Dehydrated Tissues

Abstract

Further observations are reported on a technic for preventing isotope loss or displacement in the preparation of radioautographs of thin (5u) animal tissue sections. To obtain information about the chemical nature of radioisotopes distributed in tissues, tissue sections were subjected to extraction by a variety of reagents previous to making radioautographic exposures. Results were evaluated by comparing radioautographic densities and patterns of localization from extracted tissue sections with those of control sections. Results are given for a number of rat tissues containing I131 and p32 at several time intervals. In general, it was found that (1) treatment of the tissue with organic solvents (xylol, ether, chloroform, absolute alcohol, acetone) did not result in detectable isotope loss, (2) treatment with dilute aqueous solns. extracts a major part of the isotope, and (3) treatment with reagents designed toward specific precipitation of tissue constituents (protein pre-cipitants, e.g.) is effective in retaining varying amts. of the isotope in the tissue. These results correlate well with chemical analyses of the tissues. The regions of localized isotope concn. that were studied exhibited the same solubility characteristics as the background activity of the tissue with the reagents tested.