Analysis of poisons by using electron spin resonance method

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Electron spin resonance is a sensitive method which detects only unpaired electrons (radicals). By using this method radical content in crude samples such as plasma and tissue homogenates can be measured accurately without purification. The herbicides paraquat and diquat in plasma and tissues hay been quantitized in a minute amount which had not been reported yet. To understand the mechanism of antidotal action of reductants against herbicide toxicity, vitamin E deficient rats were used, but it turned out that vitamin E had no preventive effects on paraquat toxicosis.Ascorbate radical levels were found to be elevated in rats as well as humans that were intoxicated with either paraquat, diquat or both. The levels decayd quickly in the intoxicated plasma.To obtain some insight into the toxicity of paraquat in humans, it was administered to ODS rats which are unable to synthesize vitamin C,like humans. The onset of toxicosis of ODS rats was 6 days earlier than that of normal rats. The degree of toxicity of paraquat to ODS rats was examined by changing the supplementation of vitamin C as 150,300 (sufficient level) or 3000 ppm. The excess amount of vitamin C delayd the onset of toxicosis only 1 day, whereas much larger delay was observed for normal rats. The lung vitamin C level of its oversupplied group was only 0.6-fold of the control which was not treated with paraquat. This may be one of the reasons why ODS rats exhibited the toxicosis earlier than normal rats.