Radiation Effects on Aqueous Solutions of S-(2-Aminoethyl)thiuronium Salts

Aqueous solutions of the protective compound S(aminoethyl)thiuronium (AET), buffered to favor thc formation of the active MEG form, showed marked sensitivity to ionizing radiation as measured by a reduction in concentration of - SH groups. Two methods of determining the concentration of --SH groups were used, with comparable results. The destruction of --SH groups of MEG is directly dependent on radiation dose. The G AET. The high yield suggests that a chain-typc rcaction may account for the radiation sensitivity. In deoxygenated samples the radaition effect was significantly decreased. It is suggestcd that the protective activity of AET involves not only the sensitivity to radiation of the free --SH group but also the capacity of the compound to couple with sensitivc biologic molecules and shield them from radiation damage. (auth)