Dichlorvos effect

In the body, metrifonate converts to the active metaboUte dichlorvos, (2,2-dichlorovinyl dimethyl phosphate), which is responsible for the inhibition of the enzyme acetylcholinesterase in the susceptible worm. This effect alone is unlikely to explain the antischistosomal properties of metrifonate (19). Clinically, metrifonate is effective only against infection caused by S. haematobium. Metrifonate is administered in three doses at 2-wk intervals (17). The dmg is well tolerated. Side effects such as mild vertigo, nausea, and cramps are dose-related. This product is not available in the United States. The only manufacturer of metrifonate is Bayer A.G. of Leverkusen, Germany. 

Rider JA, Moeller HC, Puletti EJ. 1967. Continuing studies on anticholinesterase effect of methyl parathion, initial studies with guthion, and determination of incipient toxicity level of dichlorvos in humans [Abstract]. Fed Proc 26 427. 

Even though all OP insecticides have a common mechanism of action, differences occur among individual compounds. OP insecticides can be grouped into direct and indirect ACHE inhibitors. Direct inhibitors are effective without any metabolic modification, while indirect inhibitors require biotransformation to be effective. Moreover, some OP pesticides inhibit ACHE more than PCHE, while others do the opposite. For example, malathion, diazinon, and dichlorvos are earlier inhibitors of PCHE than of ACHE. In these cases, PCHE is a more sensitive indicator of exposure, even though it is not correlated with symptoms or signs of toxicity. 

Verma, S.R., S. Rani, S.K. Bansal, and R.C. Dalela. 1980. Effects of the pesticides thiotox, dichlorvos and carbofuran on the test fish Mystus vittatus. Water Air Soil Pollut. 13 229-234. 

Metrifonate is an organophosphorous compound that is effective only in the treatment of S. haematobium The active metabolite, dichlorvos, inactivates acetylcholinesterase and potentiates inhibitory cholinergic effects. The schistosomes are swept away from the bladder to the lungs and are trapped. Therapeutic doses produce no untoward side effects except for mild cholinergic symptoms. It is contraindicated in pregnancy, previous insecticide exposure, or with depolarizing neuromuscular blockers. Metrifonate is not available in the United States. 

European Union regulation foresees a maximum residue limit (MRL) for dichlorvos in durum wheat at 2.0 pg/g [4], Dichlorvos is also classified as a probable human carcinogen on the basis of the effects observed in mice and rats. Therefore, the U.S. Environmental Protection Agency (EPA) proposed cancellation of most uses of dichlorvos and proposed... 

In this application, the use of wild-type electric eel AChE and a recombinant AChE, specifically selected as very sensitive to dichlorvos, was compared. The effect of the matrix extract was determined by using various sample solvent ratios, 1 2.5, 1 5, 1 10, and 1 20. The optimal extraction ratio, considering the electrochemical interferences and the effect on enzyme activity and bioavailability of the pesticide, was 1 10. 

The inhibitory effect of dichlorvos on both eeAChE and rAChE was evaluated comparing the decrease in the current produced by the choline oxidase biosensor. 

Shevchuk et al. [99] investigated extraction efficiency by extractive chromatography of the extraction of Dichlorvos using hexane, and hexane with benzene and toluene. Hexane alone was not effective, the degree of extraction at pH2.5-7.5 reached a maximum 26%. The effect of... 

T. Purshottam, and R.K. Srivatsava, Effects of high-fat and high-protein diets on toxicity of parathion and dichlorvos. Arch. Environ. Health. 39 425, 1984. 

The use of Vapona Resin Vaporizers in the home poses the possibility of an adverse effect upon persons subjected day-in and day-out to the inhalation of the vapor of dichlorvos. In order to determine the extent of this hazard, the following investigation was undertaken. 

Inhibition of the cholinesterase activity of the blood is the most sensitive means now available, with the possible exception of the inhibition of the esterase activity of the liver, for detecting the absorption of an organic phosphorus compound that is known to be capable of inducing this effect. The values indicative of cholinesterase activity are shown in Tables III and V. All subjects were exposed to the recommended dosage (one Vaporizer per 1000 cubic feet) except subjects 15 and 16, who were exposed to resin strips that contained no dichlorvos. 

Dichlorvos is a known inhibitor of cholinesterase, and it is likely that under certain conditions of use, a significant degree of inhibition might occur. However, under the conditions of these experiments, no such effect appears to have occurred. The subjects indicated no adverse effects. 

Gallery, D.J., The effect of gas velocity on fumigant action of nicotine, dichlorvos and hydrogen cyanide, ]. Stored Prod. Res., 3,17,1967. 

Under most conditions, dichlorvos is not detectable in any tissues. Dichlorvos is not stored in tissues, it does not accumulate in secretions (e.g., milk), and it is below detection levels in the blood of various species at exposure levels in excess of 10 times those effective for insect control. At exceptionally high concentrations (90mgm or about 2000 times normal exposure levels), dichlorvos was detectable in various tissues of the rat. 

Bluegill and catfish were both able to hydrolyze DFP, dichlorvos, and dimethyl 2,2,2-trichloro-l-n-butyryloxyethyl phosphonate (butonate). Catfish enzymes were also able to hydrolyze paraoxon and methyl 3-hydroxy-alpha-cronate dimethyl phosphate (mevinphos) although at a very slow rate. Kms calculated for the enzymes of both species indicated that each had a greater affinity for DFP than dichorvos. Sulfhydryl reagents and Cu2+ were found to inhibit the enzymatic activity of both organisms. Paraoxon had no effect. Cleavage products were identified as dimethyl phosphate and 2,2-dichloroacetaldehyde from dichlorovos hydrolysis and diisopropyl phosphate from the hydrolysis of DFP. 

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