Protection of the Irradiated Dog by Aminoethylisothiuronium (AET) and p-Aminopropiophenone (PAPP)

Abstract

Chemical protection of mammals against the lethal effects of ionizing radiation has been extensively investigated in recent years. In 1955 two isothiuronium derivatives, S-pf-aminoethylisothiuronium -BrHBr (AET) and the closely related propyl form (ATP), were reported by Doherty and Burnett (1) to afford approximately twice the degree of protection against ionizing radiation as MEA, on a molar basis. Khym et al. (2) found that AET and APT in neutral solution transguanylate through intermediate ring structures to quantitatively form mercaptoethylguanidine (MEG) and mercaptopropylguanidine (MPG), respectively. In acid solution, significant amounts of thiazoline derivatives were found, which had previously been shown to be more toxic and less protective than the parent compounds (3). More recent studies on the mechanism of action of AET and its derivatives have