Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of rats with chlorpromazine (CPZ, 15 mg/kg i.p. 60 min before sacrifice) did not modify cholinesterase (ChE) activity, but considerably enhanced the inhibition of total ChE induced by physostigmine (PhS, 0.5 mg/kg i.p. 40 min after CPZ) in brain, skeletal muscle, myocardium, lung, liver, and kidney. Additional experiments also showed a prolongation of PhS inhibition by CPZ in brain. The enhanced inhibition of total ChE due to CPZ depended in most peripheral organs on the effect on pseudoChE (as measured by a spectrophotometric method), except in the case of skeletal muscle in which potentiation of PhS effect was observed on true acetylcholinesterase (AcChE). The results indicate that the potentiation by CPZ of PhS inhibition occurs in all organs tested and is relatively non specific. CPZ was found to potentiate slightly the effects of Mevinphos but did not interact with Carbaryl, Diazinon or Azinphos. Furthermore, haloperidol did not potentiate the effects of physostigmine.
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PMID:Interactions between anticholinesterase agents and neuroleptics in terms of cholinesterase inhibition in brain and other tissues of rats. 613 14

Blood cholinesterase (CHE) activities and urinary dialkyl phosphate levels of five mixer-loaders and four mixer-loader applicators, using a closed-transfer system in conjunction with mixing-loading and application equipment, were monitored over a period of 18 weeks. Airborne pesticide residues in the breathing zone during mixing-loading and the transfer of concentrated liquid pesticide from their original container to mix and spray tanks were determined along with airborne residues during ground application. Blood ChE activities of the majority of the workers increased slightly during the study with increased use of toxic organophosphates and carbamates. Urinary dialkyl phosphate levels varied between 0.02 and 2.4 ppm. During the study, the blood ChE activities of two mixer-loaders decreased and dialkyl phosphate levels of 2.4 ppm were found in the urine of one worker. An investigation indicated that the workers had failed to use the provided closed-transfer system. Airborne residues from liquid pesticides during closed transfer and mixing-loading averaged 5.8 microgram/m3, while residues from dusty powders averaged 152 microgram/m3. Airborne residues during ground application averaged 3.7 microgram/m3 during the workday. Mevinphos residues on cloth patches averaged 0.2 microgram/cm2.
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PMID:Safety effectiveness of closed-transfer, mixing-loading, and application equipment in preventing exposure to pesticides. 738 90

Mevinphos (trade name, Phosdrin), a category 1 organophosphorus insecticide, has been used mainly as a cleanup pesticide for vegetable crops. A risk assessment for occupational and dietary exposure to mevinphos was initiated because of the high acute toxicity of the compound. Repetitive dosing with mevinphos did not cause any discernible histopathological effects in mice or rats, nor was it oncogenic in either species. The principal toxic effects of mevinphos, both short- and long term, were due to inhibition of cholinesterase activity. Consequently, potential adverse effects from short-term exposures were the primary concern. A human no-observed-effect level (0.025 mg/kg) for cholinergic signs was used as the regulatory basis for calculating margins of safety (MOSs) for potential acute dietary and short-term occupational exposures. Estimates of exposure to mixer/loaders, pilots, and flaggers associated with aerial application of mevinphos were based on passive dosimetry. Because no acceptable exposure studies for work tasks associated with ground application of mevinphos were available, surrogate data based on ground application of oxydemeton-methyl were used. Exposure estimates for field workers and harvesters relied on measured dislodgeable foliar residues of mevinphos and transfer factors generated from studies of other active ingredients. MOSs for mean acute occupational exposure of mixer/loader/applicators associated with ground application and of harvesters working in fruit trees were less than the value conventionally recommended to protect people from the toxic effects of mevinphos. MOSs for the 95th percentile of short-term worker exposure for all mixer/loader work categories associated with mevinphos application were also inadequate. Calculated MOSs for potential acute dietary exposure to measured residue levels of mevinphos were adequate for the various population subgroups. However, 25 of the USEPA tolerances for mevinphos on agricultural commodities were not adequate to protect for the toxic effects of mevinphos from theoretical acute dietary exposure to one or more population subgroups if commodities are consumed with residues at the tolerance level. When the mean short-term occupational exposures were combined with potential acute dietary exposure, the MOSs for mixer/loaders engaged in aerial applications, as well as ground applications, were inadequate to protect people from the toxic effects of mevinphos. As mitigation of the estimated excessive occupational exposures did not appear possible, both California and the USEPA were preparing to cancel registration of the product. However, an agreement was worked out between the manufacturer and the two agencies that ended production for domestic use but allowed existing stocks in the channels of trade to continue to be used for a limited period.
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PMID:Risks from occupational and dietary exposure to mevinphos. 871 19

Based on the principle of enzyme inactivation, a butyrylcholinesterase (EC 3.1.1.8.) biosensor, to determine some organophosphorus (ORP) pesticides (Fenitrothion, Diazinon, Parathion ethyl, Mevinphos and Heptenophos) in soil extracts, is presented. The enzyme was immobilized on pre-activated Pall Biodyne(TM) transfer membranes, which were physically attached to the sensitive ends of glass pH electrodes. Contact of the enzyme with pesticide samples results in specific inhibition of enzyme activity. Sensor calibration was possible by correlating the inhibition of enzyme activity (monitored by observing reduction in electrode potential changes with substrate additions) with varying concentrations of pesticide compounds in a buffer solution. A simple procedure was designed to extract ORP pesticides from spiked soil samples using a mixture of dichloromethane and acetone as the extraction solvent mixture. The sensor was successfully used to determine pesticide concentrations ranging from a low of 35 ppb (Diazinon) to 21 ppm (Fenitrothion) in soil, with resultant relative standard deviations of percentage enzyme inactivation less than 12%. The complete extraction and analytical procedure is simple, inexpensive and rapid. Mass production of the enzyme membranes and their easy attachment to the electrodes, render them disposable after a single use. The biosensor is seen as a potential analytical instrument for early warning against pesticide contaminations in soil.
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PMID:Application of a cholinesterase biosensor to screen for organophosphorus pesticides extracted from soil. 1896 76

Age-related differences in the acute neurotoxicity of cholinesterase (ChE)-inhibiting pesticides have been well-studied for a few organophosphates, but not for many others. In this study, we directly compared dose-responses using brain and red blood cell (RBC) ChE measurements, along with motor activity, for mevinphos, monocrotophos, dicrotophos, and phosphamidon. Long-Evans hooded male rats were tested as adults and at postnatal day (PND) 17; PND11 pups were also tested with dicrotophos only. All chemicals were administered via oral gavage and tests were conducted at times intended to span peak behavioral and ChE effects. All OPs tested produced a rapid onset and recovery from the behavioral effects. There were age-related differences in the inhibition of brain, but not necessarily RBC, ChE. Mevinphos was clearly more toxic, up to 4-fold, to the young rat. On the other hand, monocrotophos, dicrotophos, and phosphamidon were somewhat more toxic to the young rat, but the magnitude of the differences was < 2-fold lower. Motor activity was consistently decreased in adults for all chemicals tested; however, there was more variability with the pups and clear age-related differences were only observed for mevinphos. These data show that three of these four OPs were only moderately more toxic in young rats, and further support findings that age-related differences in pesticide toxicity are chemical-specific.
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PMID:Age-related differences in acute neurotoxicity produced by mevinphos, monocrotophos, dicrotophos, and phosphamidon. 2167 67