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:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The combined effects of ozone and nitrogen dioxide were assessed in an in vitro test system utilizing human red cells. In general, these two pollutants had additive effects on the parameters measured which included osmotic fragility, acetylcholinesterase activity, lipid peroxidation, reduced glutathione and methemoglobin levels. However, at lower pollutant doses a synergistic increase in lipid peroxides was noted while at higher doses the effect became less than additive. Further studies of this observation suggested that ferrous hemoglobin potentiates ozone-induced lipid peroxidation while methemoglobin, resulting primarily from nitrogen dioxide, inhibits this process. Ozone was also found to potentiate the methemoglobinemic effects of nitrogen dioxide, particularly in sequential studies in which ozone exposure preceded nitrogen dioxide. Inasmuch as the effects of these two pollutants vary from protective to synergistic depending on the pollutant concentration, duration and sequence of exposure, as well as on the parameter assayed, it would appear that the approach to in vivo study of the combined effects of ozone and nitrogen dioxide should be aimed at simulating ambient conditions as closely as possible.
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PMID:Combined exposure to ozone and nitrogen dioxide. 126 95

The inevitable chemical risks present in a synthetic threads and fibres aggregate works determine a careful and permanent surveillance of employees' state of health, especially where the occupational risk is known to exist. Besides the usual labour protection measures, screening for the early detection of some biochemical or biotoxicological changes induced by the contact with the chemical noxae in the labour environment are performed. This paper presents the results of a complex biochemical and biotoxicological screening including about 300 employees working at the polyplants in the melanin section where the major chemical noxa is acrylonitrile. The total proteins, hemoglobin, methemoglobin and cholinesterase activity were determined.
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PMID:[Biotoxicological research on a segment of the population in an industrial environment. I. Total proteins, hemoglobin, methemoglobin and cholinesterase]. 210 Aug 52

Treatment of washed erythrocytes with tert-butyl hydroperoxide (0.5 mM, 10 min) inhibited basal Ca2+ + Mg2+-ATPase activity by 40% and calmodulin-stimulated activity by 54%. The inhibition was accompanied by the formation of methemoglobin and the aggregation of some membrane proteins into a high-molecular-weight polymer. Membranes, isolated from washed erythrocytes, showed a similar pattern of inhibition. Basal Ca2+ + Mg2+-ATPase activity was inhibited 50% at 10 min and 70% at 30 min while calmodulin-stimulated activity was inhibited 70% at 10 min and 84% at 30 min. Thiobarbituric acid-reactive products formed slowly during the first 10 min and then increased sharply between 10 and 30 min. The polymerization of membrane proteins was also observed during the tert-butyl hydroperoxide exposure. Inhibition of erythrocyte membrane enzymes was selective. The Na+ + K+-stimulated Mg2+ ATPase, like the Ca2+ + Mg2+-ATPase, was sensitive to membrane oxidation but the activities of Mg2+-ATPase and acetylcholinesterase were less inhibited by tert-butyl hydroperoxide. Acetylcholinterase was found to be very resistant to hydroperoxide treatment with less than 10% loss of activity. The effects of two other hyproperoxides on enzyme inhibition were studied also. Cumene hydroperoxide (0.5 mM) was found to be as potent as tert-butyl hydroperoxide but hydrogen peroxide at 10 mM did not produce thiobarbituric acid-reactive products or inhibit Ca2+ + Mg2+-ATPase activity until after 20 min. The selective effects of peroxides on these enzyme activities are discussed.
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PMID:Hydroperoxides selectively inhibit human erythrocyte membrane enzymes. 252 25

When egg yolk diacylglycerophosphocholine (PC) liposomes were incubated with human oxyhemoglobin, peroxidation of liposomal lipid was induced, as monitored by an increase of thiobarbituric acid (TBA)-reactive substances, an increase of lipid hydroperoxides and the generation of chemiluminescence in the presence of luminol. During the reaction, cytotoxic substance(s), which induced shedding of acetylcholinesterase-enriched vesicles from human erythrocytes, were produced. Formation of TBA-reactive substances and lipid hydroperoxides preceded generation of chemiluminescence, conversion of oxyhemoglobin to methemoglobin and production of the toxic substances. Either superoxide dismutase or catalase could suppress generation of chemiluminescence, but not other events. Methemoglobin or ferrous ion plus ascorbate could induce peroxidation of the liposomes without production of the cytotoxic substance(s). Synthetic PCs containing both saturated and polyunsaturated fatty acyl chains caused the production of cytotoxic products which induced shedding of vesicles from erythrocytes, whereas those containing only polyunsaturated fatty acyl chains did not, suggesting that the molecular species which can produce cytotoxic products may be phospholipids containing both saturated and polyunsaturated fatty acids. The mechanism of oxyhemoglobin-induced peroxidation of lipids will be also discussed.
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PMID:Generation of toxic phospholipid(s) during oxyhemoglobin-induced peroxidation of phosphatidylcholines. 338 89

F344/N rats and B6C3F1 mice were exposed to 0, 1, 3, or 6 ppm methyl isocyanate by inhalation for 6 hr on 4 consecutive days. Deaths of rats were observed following 3 ppm exposures, and mice died after exposures to 6 ppm. Deaths appeared to be related to severe respiratory distress. Survivors in high dose groups lost weight initially, then gained weight at rates equal to controls throughout a 91-day recovery period. Lung weights increased significantly in male and female rats exposed to 3 ppm, but no persistent changes in brain, kidney, thymus, spleen, liver, or testis weights were seen in either mice or rats. Blood and serum from male and female rats were taken for clinical pathology and hematology assessments on day 7 of postexposure, the day prior to the first observed deaths of these animals. No changes or only slight changes were seen in measures of serum alanine aminotransferase, sorbitol dehydrogenase, alkaline phosphatase, or in blood and brain cholinesterase activities. However, serum creatine kinase increased with dose in both males and females. Blood urea nitrogen, creatinine, and methemoglobin were unchanged. No changes were seen in counts of red blood cells or platelets, or in red cell indices. Hemoglobin concentrations and hematocrits were slightly elevated. No changes were noted in absolute leukocyte counts, but counts of segmented neutrophils increased and lymphocytes decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The toxicity of inhaled methyl isocyanate in F344/N rats and B6C3F1 mice. II. Repeated exposure and recovery studies. 362 27

The effects of human oxyhemoglobin (HbO2), human methemoglobin (MetHb), and porcine serum albumin (PSA) on the activity of acetylcholinesterase (AChE) isolated from Electrophorus electricus were examined. HbO2 produced a dose-dependent reduction in AChE activity. Fifty percent of activity was obtained at 5 microM HbO2, while 95% inhibition was obtained at 50 microM. In this concentration range MetHb and PSA had little effect on esterase activity.
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PMID:Oxyhemoglobin inhibition of acetylcholinesterase activity. 372 81

n-Butyl mercaptan (nBM) is a breakdown product of S,S,S,-tri-n-butyl phosphorotrithioate (DEF) and S,S,S-tri-n-butyl phosphorotrithioite (merphos) in hens and in the environment. n-Butyl disulfide (nBD) is an oxidation product of nBM. A single 500 mg/kg dose of nBM and nBD was administered in gelatin capsules to groups of five 12-month old laying hens. A third group (five hens) was given gelatin capsules. One day after administration, the hens exhibited weakness which progressed to unsteadiness and inability to stand by the third day. These signs were accompanied by a pale comb 18--24 hr after dosing, which changed to dark color at 48 hr. Treated hens improved with time. Heinz bodies and extensive erythrocyte deformation and lysis were observed in blood smears taken from hens 24 and 48 hr after treatment. Hemoglobin concentration, packed cell volume, erythrocytes, and glucose-6-phosphate dehydrogenase activity were significantly lower than controls, while methemoglobin was significantly higher. As the clinical condition of these hens improved, these hematologic changes disappeared. nBM caused an initial increase in plasma butyrylcholinesterase activity which was dose-dependent and returned to normal by the end of the 28-day experiment. Also, brain acetylcholinesterase activity was not different from that of the control at termination.
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PMID:Heinz body production and hematological changes in the hen after administration of a single oral dose of n-butyl mercaptan and n-butyl disulfide. 687 30

Recombinant alpha-D-galactosidase (rGal) from soybean (Glycine max) hydrolyzed the immunodominant alpha-D-galactose residue from the B epitope of red blood cells. This converted type B erythrocytes to type O which are "universally" transfusable. Type B red blood cells were obtained from four different donors and enzymatically converted. Cell function parameters, including red cell indices, pH, methemoglobin, carboxyhemoglobin, osmotic fragility, hemolysis, 2,3-diphosphoglycerate, cholinesterase, ATP, and antigen typing of treated cells were compared to controls. These pilot studies indicate that rGal could have potential biotechnical application in the production of universally transfusable red blood cells.
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PMID:Seroconversion of type B to O erythrocytes using recombinant Glycine max alpha-D-galactosidase. 978 52

To evaluate the susceptibilities of human blood constituents to the low levels of ozone used in ozonated autohemotherapy (40 microgO3/ml), we quantified plasma antioxidants and erythrocyte constituents after rapid mixing of human whole blood with ozone at 20, 40, 60, and 100 microg/ml blood. Ascorbic acid, uric acid, and alpha-tocopherol in plasma decreased as ozone increased, but bilirubin was unaffected. The content of thiobarbituric acid-reactive substances in plasma was increased by ozone. However, the content of thiobarbituric acid-reactive substances and alpha-tocopherol in the erythrocyte membrane was not significantly affected. No significant changes occurred in the content of methemoglobin, cytoskeleton proteins or erythrocyte enzymes such as Na+/K+-ATPase, acetylcholinesterase, catalase, glutathione peroxidase, glutathione reductase, and superoxide dismutase at all the ozone levels tested. A decrease in reduced glutathione in erythrocytes was the only significant change caused by the ozone level used for autohemotherapy. It may be one of the chemical events responsible for the beneficial effects of ozonated autohemotherapy.
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PMID:Susceptibilities of plasma antioxidants and erythrocyte constituents to low levels of ozone. 1006 48

Sodium fluorescein angiography is a widely used technology in ophthalmology, which allows us to visualise the chorioretinal microcirculation. Previous reports showed a prolongation of the retinal circulation time along with erythrocyte hyperaggregation and a decrease of erythrocyte acetylcholinesterase activity and a possible interference with the erythrocyte's membrane fluidity. The aim of the present work is to investigate the influence of sodium fluorescein on the hemorheological profile of a group of 23 non-insulin dependent diabetes mellitus (NIDDM) patients undergoing routine retinal angiography. Thirty minutes after the endovenous administration of the fluorescein there was: (I) an increase of whole blood viscosity (p = 0.015), erythrocyte elongation index (EEI, p < 0.05), whole blood pH (p < 0.001), methemoglobin (p < 0.001) and carboxyhemoglobin (p < 0.001) concentrations; (II) no variation of plasma osmolality and erythrocyte aggregation index (EAI); (III) a decrease of the erythrocyte acetylcholinesterase activity, p < 001; (IV) no variation in membrane lipid fluidity, although 1,6-diphenyl-1,3,5-hexatriene (DPH) correlated directly with the EEI, while 1,4-trimethyl-phenyl-1,3,5-hexatriene (TMA-DPH) and EAI correlated inversely, suggesting that the decreasing EEI (lower erythrocyte deformablity) might be associated with an increased rigidity of the external polar region and fluidification of the hydrophobic region of the erythrocyte membrane, with an increasing EAI. In conclusion, the endovenous administration of sodium fluorescein in NIDDM patients during the retinal angiography procedure interferes with the erythrocyte membrane and possibly with the microcirculatory blood flow.
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PMID:Sodium fluorescein influence on the hemorheological profile of non-insulin dependent diabetes mellitus patients. 1041 8


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