Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.8 (cholinesterase)
12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum cholinesterase activity was determined in 30 female patients anaesthetized with enflurane for excision of lump in the breast. In all 30 patients biopsy of the tumor was negative for carcinoma. Blood samples were taken before induction of anaesthesia, at the end of the operation and 24 hours after the operation. Enzymatic determinations were performed by the Boerhinger cholinesterase kit. Enzyme levels were found sufficiently high at the end of the operation and returned to the preoperative levels 24 hours post-operatively.
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PMID:Serum cholinesterase activity following enflurane anaesthesia. 72 26

A serious limitation to the diagnosis of mild organophosphate poisoning and to the preventive screening of organophosphate-exposed workers has been the large interindividual variability in erythrocyte cholinesterase. This makes it necessary to obtain a pre-exposure baseline measurement of enzyme activity as a basis for evaluating subsequent declines. To evaluate a new battery-operated colorimetric erythrocyte cholinesterase kit, 23 workers at a Mexican pesticide formulation plant were examined. All workers had normal cholinesterase, and exposed and unexposed workers were found to have similar mean cholinesterase levels. Although erythrocyte cholinesterase was found to have a coefficient of variation of 12% (similar to that reported in previous studies), hemoglobin-adjusted erythrocyte cholinesterase had a markedly reduced coefficient of variation (7.4%). The 90% confidence interval (24.9-31.7 IU/g hemoglobin) resulted in a lower normal limit that is 78% of the upper limit. Even if a pre-exposure baseline were high normal but unknown at the time of examination, the supervising clinician can be confident that any person with a normal result will be no less than 78% of baseline. The kit is moderately priced, easy to use in the field setting, and the low variability to the assay should allow improvement in diagnosis, screening, and in the epidemiologic evaluation of exposure.
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PMID:Monitoring organophosphate insecticide-exposed workers for cholinesterase depression. New technology for office or field use. 155 78

For assaying plasma cholinesterase (EC 3.1.1.8) activity and phenotyping by means of dibucaine inhibition, we have compared a commercially available kit, in which butyrylthiocholine is used as substrate, with two reference methods, one using benzoylcholine and the other propionylthiocholine. With 50 different samples of three of the most common genetic variants, we could clearly differentiate the variants with benzoylcholine and dibucaine, whereas there was some overlap of the E1uE1u and E1uE1a phenotypes with the other two substrates at 30 degrees C. The phenotypes were better differentiated at 25 degrees C, and in our hands the use of butyrylthiocholine was preferable to propionylthiocholine for phenotyping with dibucaine. The affinity of the usual and atypical homozygotes for fluoride with butyrylthiocholine gave an inverted response to the affinity of these variants for the anion with benzoylcholine. We suggest that this may be explained by the role of the chromogen or its products in the assay procedure with the thiocholine substrate.
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PMID:Comparison of a commercially available assay system with two reference methods for the determination of plasma cholinesterase variants. 661 19

Blood cholinesterase activity is an efficient indicator of exposure to organophosphate insecticides. Field methods, in spite of lacking sensitivity, are important when practical determinations and immediate results are necessary One of the mostly used field methods to assess blood cholinesterase activity is the Lovibond Cholinesterase Field Kit. This paper proposes to substitute the comparator disk of the Lovibond Field Kit with a set of standard solutions that exhibit similar colours. Dilutions of Bromothymol blue, whole blood and acetic acid in different concentrations were used to construct a set of coloured solutions which correspond to different degrees of ChE inhibition. The comparison of acetylcholinesterase activity measured with the two methods showed good agreement and satisfactory reproducibility of results. The use of a standard colored solution kit seems more suitable and manageable for field studies than the Lovibond comparator disk.
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PMID:A field method for the determination of whole blood cholinesterase. 793 48

A semiquantitative tintometric field kit has been used in the developing world for almost 30 years to measure whole blood cholinesterase levels in persons exposed to organophosphate pesticides. The validity of this screening kit was evaluated among 79 workers heavily exposed to organophosphates by comparison with a reference assay for erythrocyte cholinesterase. Overall correlation between the two methods was good. However, either sensitivity or specificity of the tintometric kit was less than 75% for each of the three tintometric categories commonly used to define the limit of normal. Because baseline erythrocyte cholinesterase levels were not available for this population, the true sensitivity and specificity of the tintometric assay may be even lower.
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PMID:Screening for insecticide overexposure under field conditions: a reevaluation of the tintometric cholinesterase kit. 812 72

The extensive international use of organophosphorus compounds (OP) results in numerous acute intoxications each year. OPs inhibit acetylcholinesterase, the enzyme responsible for breaking down the neurotransmitter acetylcholine. The World Health Organization recognizes cholinesterase (ChE) biomonitoring as a preventive measure against OP overexposure. The aim of this study was to determine if dermal OP contamination could interfere with current field ChE biomonitoring assays, which use a fingerstick blood sample. In this study we also sought to determine if high levels of a plasma enzyme, A-esterase, could protect ChE from inhibition by hydrolyzing environmentally generated oxons potentially present in a fingerstick sample. A heparinized venous blood sample was collected from a volunteer. Erythrocyte acetylcholinesterase (AChE) and plasma butyrylcholinesterase (PChE) activities were measured using a field-based colorimetric cholinesterase kit. ChE dose-response curves were constructed by allowing 10-microliters blood samples to contact environmentally realistic levels of OP thioate and oxon for 10 s. An inhibition threshold could not be established for PChE when exposed to oxon within the time necessary to perform a fingerstick analysis. AChE was also inhibited by trace amounts of oxon consistent with previously reported environmental levels. These findings suggest that the reliability of field-based biomonitoring results is limited if OP residues remain on a skin surface at the time of sample collection. A-esterase's role in protecting ChE activity was investigated using capillary and venous blood from 30 unexposed individuals. Baseline ChE activities were measured, as were individual A-esterase activities using paraoxon, diazoxon, and phenylacetate as substrates. Results were then compared to ChE activities measured after 10 s of contact with an environmentally realistic amount of OP, containing 1% oxon. Both ChE activities were significantly inhibited, with capillary values being significantly more inhibited than their venous counterparts. However, no protective effect could be associated between the degree of A-esterase activity and the subsequent level of ChE inhibition observed in an individual's blood. These results suggest that (1) if there is any uncertainty about OP skin contamination, venous blood would be a more appropriate specimen to employ when using field ChE biomonitoring kits--it is collected in larger volumes and has essentially no direct contact to dermal surfaces; and (2) A-esterase activity demonstrates no protective effect against ChE inhibition upon a blood droplet's brief contact with an OP residue containing traces of oxon.
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PMID:Simulated dermal contamination with capillary samples and field cholinesterase biomonitoring. 916 60

Indicator tubes from field kits for detection of organophosphorus compounds in the air were found on the territory of Croatia, in barracks liberated during the war years of 1991/1992, and were analysed during 1993/95. The detection kit consisted of glass indicator tubes with two sealed vials within each tube, a device for opening the tubes and breaking the vials, and an air sampling pump. The tubes were marked with serial numbers and expiry dates (1974-1992), but the description as to their contents was unavailable. The aim of this study was to identify the contents of the indicator tubes and to establish whether they were still suitable for detection of organophosphorus compounds. One vial was found to contain a cholinesterase (EC 3.1.1.7) preparation, while the other vial contained a non-thiocholine substrate and a pH-sensitive indicator (most probably cresol red). Applying DDVP as an organophosphorus cholinesterase inhibitor, it was found that all sets of indicator tubes were suitable for use regardless of the indicated expiry dates. Furthermore, the same tubes were found suitable for detection of organophosphorus compounds in water.
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PMID:Identification of the contents and the shelf-life of indicator tubes from field kits for detection of organophosphorus compounds in the air. 943 34

Peach harvest workers were evaluated for exposure to azinphosmethyl residues by measuring foliar residues, urinary alkylphosphate metabolites, butyrylcholinesterase (BChE), acetylcholinesterase (AChE), and dermal residues using clothing and skin washes. Workers entered orchards 51 days after application and worked in treated fields for 10 of the next 17 days. Dislodgeable foliar residues ranged from 0.82 to 1.72 microg/cm2 and did not change significantly over the study period. Combined mean dermal exposure for the 3 consecutive monitoring days was 32 mg and ranged from 17.9 to 60.5 mg. Overall mean excretion levels for the 5 monitoring days were 1.7 mg dimethylphosphate and 1.9 mg dimethlythiophosphate. There was no significant difference in BChE between the exposed harvesters and minimally exposed sorters. The exposed group had significantly lower AChE values than the sorters for 2 post-exposure blood draws by three testing methods, while no significant difference was found for the pre-exposure blood draw. The AChE values for the post-exposure blood samples for the exposed workers decreased significantly about 10-20% over the 3-week exposure period but increased or remained constant for the sorters. Urinary metabolite excretion increased with continuous exposure and was inversely correlated with both AChE and BChE but was not correlated with dermal exposure measurements. High correlations were generally observed between AChE measurements taken in the field using a new spectrophotometric kit and laboratory AChE measurements.
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PMID:Monitoring Peach Harvest Workers Exposed to Azinphosmethyl Residues in Sutter County, California, 1991 967 19

Potatoes contain antinutritional and potentially toxic compounds including inhibitors of digestive enzymes, hemagglutinins, and glycoalkaloids. Solanum glycoalkaloids are reported to inhibit cholinesterase, disrupt cell membranes, and induce teratogenicity. In this overview, we describe the role of potatoes in the human diet, reported changes in glycoalkaloid content of fresh and processed potatoes during storage, under the influence of light and radiation, following mechanical damage, and as a result of food processing. Also covered are safety aspects and suggested research needs to develop a protocol that can be adopted by the potato producers and processors to minimize post-harvest synthesis of glycoalkaloids in potatoes. Reducing the glycoalkaloid content of potatoes will provide a variety of benefits extending from the farm to processing, shipping, marketing, and consumption of potatoes and potato products. A commercially available ELISA kit is described which permits rapid assay of glycoalkaloid content of parts of the potato plant including leaves, tubers, and peel, as well as processed potato products including french fries, chips, and skins. Understanding the multiple overlapping aspects of glycoalkaloids in the plant and in the diet will permit controlling postharvest glycoalkaloid production for the benefit of the producer and consumer.
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PMID:Postharvest changes in glycoalkaloid content of potatoes. 1033 73

Organophosphate and carbamate ester insecticides, main causes of pesticide poisoning, inhibit cholinesterase (ChE) enzymes. The aim of this study was to measure and compare baseline values for pseudocholinesterase and acetylcholinesterase (AChE) enzyme activities of different blood fractions in the dog to aid in diagnosis of anticholinesterase poisoning. After collecting blood samples from 23 6-24-mo-old male beagle dogs, Ellman's colorimetric assay was run on plasma, red blood cells (RBC), and whole blood fractions prepared in triplicate. The procedure described in a commercially available kit was applied to plasma and RBC. Hemolyzed whole blood fractions (final dilution 1:8) avoided the time-consuming and laborious separation of plasma and RBC. In addition to the kit substrate acetylthiocholine (ASCh), we used butyrylthiocholine (BSCh) as substrate. Whatever the substrate, ChE activity was lower in RBC than in other blood preparations. It was higher when using ASCh rather than BSCh as substrate (mean IU/L+/-SD): 563+/-144 and 303+/-45 respectively, in contrast to plasma (1640+/-310 and 2510+/-450). Whole blood enzyme activity did not differ significantly according to substrate: ASCh, 1590+/-190; BSCh, 1620+/-250) with a 2 to 3% within-day coefficient of variation. Enzyme activity was significantly lower in dogs <1-y old. This study confirms the low ChE activity in dog RBC compared to other species and other blood fractions. It shows that using whole blood instead of separating RBC from plasma minimizes the variability of ChE activity in the hemoglobin-rich fraction.
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PMID:Acetyl- and pseudo-cholinesterase activities of plasma, erythrocytes, and whole blood in male beagle dogs using Ellman's assay. 1092 85


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