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1997
Book Article
Titel
Results of in vivo and in vitro experiments with oximes as antidotes against sarin and soman poisoning
Abstract
The toxic effects of nerve agents and organophosphorous pesticides are mainly due to inhibition of AChE by phosphorylation of its active site. At least partial deactivation of the inhibited enzyme can be achieved by pyridinium oximes. In soman poisoning oxime therapy often fails due to the rapid transformation of the inhibited enzyme into a non-reactivatable form ("ageing") brought about by hydrolysis of the 1,2,2-trimethylpropyl-phosphonic acid ester. In this study, reactivation experiments were performed in vitro and the protection potential was investigated in vivo using the oximes HI6 and HLö7 as well as Toxogonin. The reactivation of solubilized bovine and human red blood cell AChE was greater with HLö7 as compared with HI6 or Toxogonin after inhibition with soman or sarin. In mice the protective ratios against soman and sarin were best with HLö7 followed by HI6 and Toxogonin. In guinea pigs HI6 revealed a higher protection ratio than HLö7. The results of the in vitro experiments demonstrate a marked reactivation potential for HLö7 suggesting that reactivation may play a role for survival if ageing is retarded in vivo, though the pH-value prevented ageing of the enzyme in the in vitro assays.