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)

A 65-year-old Caucasian female developed an intermediate syndrome seven days after an acute cholinergic crisis, caused by the ingestion of fenthion. Cholinesterase activity in the blood, plasma and red cells was monitored daily by the method according to Nenner and serial serum fenthion levels were measured by capillary gas chromatography. Electromyographic studies showed fade on tetanic stimulation by means of surface electrodes at 20 Hz of the left M. abductor digiti quinti at day 7, which could no longer be observed at day 19. Fade on low-frequency stimulation and post-tetanic facilitation were both absent. A biopsy of the N. suralis was normal. A biopsy of the M. tibialis anterior revealed a limited rhabdomyolysis with a very weak staining for cholinesterase. It is hypothesized that the pathophysiologic process underlying the syndrome is the result of a time-confined phenomenon, which includes both changes in the postsynaptic structures by a desensitization process and a gradually restoring ratio of acetylcholine to acetylcholinesterase. This hypothesis is suggested by the similarity in the EMG-findings of this patient and those in myasthenia gravis, which is known to be characterized by a postsynaptic transmission defect.
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PMID:Postsynaptic neuromuscular dysfunction in organophosphate induced intermediate syndrome. 164 23

Ninety-seven agricultural workers were monitored for absorption of the organophosphorus pesticides methidathion, vamidothion, and azinphos-methyl, which were sprayed in an orchard during two seasons. Low levels of only one dialkylphosphorus metabolite (dimethyl phosphorothioate) were found in only eight workers in pre-exposure urine samples. More than one dialkylphosphorus metabolite was detected in almost all exposed individuals in after-exposure urine samples. The highest concentrations were measured after exposure to azinphos-methyl; the median concentrations of dimethyl phosphorodithioate and dimethyl phosphorothioate were 0.92 and 0.78 nmol/mg creatinine with a concentration range up to 14.3 and 53.7, respectively. Three diethylphosphorus metabolites were also detected in some samples, but at lower concentrations. Cholinesterase activities were decreased (31-48%) in the serum of 12 workers; four of those workers had no dialkylphosphorus metabolites in the urine. Paraoxonase and arylesterase activities in the serum were unaffected by the absorption of pesticides, and there was no correlation between the activities of these esterases and the metabolite concentrations in the urine. This study confirmed that dialkylphosphorus metabolites in the urine are a more sensitive index of absorption than cholinesterase inhibition in the serum but lack of correlation between cholinesterase inhibition and metabolite concentration indicates that both parameters should be monitored.
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PMID:Dialkylphosphorus metabolites in the urine and activities of esterases in the serum as biochemical indices for human absorption of organophosphorus pesticides. 165 Jan 68

Paraoxon and chlorpyrifos-oxon, the active metabolites of the organophosphorus insecticides parathion and chlorpyrifos, respectively, are hydrolyzed by an "A"-esterase, paraoxonase, which is present in the sera of several mammalian species. In this study, we investigated whether levels of serum paraoxonase activity in laboratory animals can influence the in vivo toxicity of paraoxon and chlorpyrifos-oxon. Paraoxonase was found to be 7-fold higher in rabbit serum than in rat serum. The dose of paraoxon required to produce similar signs of toxicity and similar degrees of cholinesterase inhibition in rats and rabbits (0.5 and 2.0 mg/kg, respectively) differed by 4-fold. Paraoxonase was then purified from rabbit serum and 8.35 units was injected in the tail veins of rats, increasing the peak hydrolytic activity of rat serum by 9-fold toward paraoxon and by 50-fold toward chlorpyrifos-oxon. The increase in serum paraoxonase/chlorpyrifos-oxonase activity was long-lasting, with a 2- and 10-fold increase, respectively, still present after 24 hr. Thirty minutes following enzyme injection, rats were challenged with an acute dose of paraoxon or chlorpyrifos-oxon given by the intravenous, intraperitoneal, dermal, or oral route. Cholinesterase activities were measured in plasma, red blood cells, brain, and diaphragm after 4 hr. Rats pretreated with paraoxonase exhibited less inhibition of cholinesterase than vehicle-treated controls following identical doses of paraoxon, particularly when the organophosphate was given iv or dermally. A very high degree of protection, particularly toward brain and diaphragm cholinesterase, was provided by paraoxonase pretreatment in animals challenged with chlorpyrifos-oxon by all routes. These results indicate that levels of serum paraoxonase activity can affect the toxicity of paraoxon and chlorpyrifos-oxon.
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PMID:Serum paraoxonase and its influence on paraoxon and chlorpyrifos-oxon toxicity in rats. 169 Apr 62

The morphological innervation pattern of developing fetal and neonatal rabbit hearts was delineated histochemically by a cholinesterase/silver procedure and immunohistochemically with the monoclonal antibody HNK1, an antibody which recognizes some cells derived from neuroectoderm. Cholinesterase-containing nerves appeared distally on the outflow tract by gestational day 15 (G15). Isolated cells with cholinesterase-stained fine processes were present near the base of the pulmonary trunk. HNK1 antibody stained the same nerves and ganglia revealed by the cholinesterase reaction and other nerves in the rabbit heart. It was used to confirm that cells with fine neuron-like processes were present before nerve ingrowth. The G14 heart contained many HNK1 staining cells in the right atrium, outflow, and inflow tracts; cells with fine processes were few but increased at G16. By G17, a plexus of interweaving nerves and associated cells began to form at the base of the pulmonary trunk. Fine nerves encircled the base of the aorta, and others crossed the intercaval region dorsally. At G19, nerves 1) extended downward from a rich "bulbar" plexus along the front ventricular surface, 2) grew near the epicardial surface at the base of the heart along the atrial floor and ventricular roof, 3) traversed the vena cavae and intercaval region to enter the atrial roof, and 4) crossed the coronary sinus to reach the back ventricular walls. By G23, cholinesterase-staining nerves and ganglia in the atria and, epicardially, in the ventricles formed the general innervation pattern of the newborn and adult rabbit heart.
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PMID:Morphological innervation pattern of the developing rabbit heart. 171 72

Histochemical staining techniques that identify intact motor nerve fascicles are available to aid free muscle transplantation. Cholinesterase activity of myelinated axons can be identified by Karnovsky and Roots's technique. Axon viability can be assessed based on the presence of axoplasmic enzyme activity. By reacting serial sections for cholinesterase activity and carbonic anhydrase activity, which labels sensory axons, an accurate cross-sectional map of regenerating or functional sensory and motor nerve fibers can be constructed. Resolving the motor and sensory identities of fascicles in a mixed peripheral nerve should lead to more precise coaptation of recipient motor fibers to the motor nerve of the transferred muscle and enhance reinnervation.
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PMID:Histochemical staining of nerve endings as an aid to free muscle transplantation. 172 64

During 1979-1987 studies were carried out in vitro on the serum cholinesterase levels of 46 vector control workers exposed to insecticides on a daily basis but without clinical manifestations of insecticide poisoning. The results were compared with those of a control group of workers who had not been exposed to insecticides at home or at work. Cholinesterase levels of both groups were determined by a standard colorimetric method. Suppressed serum cholinesterase levels were detected in all 46 workers exposed to insecticides, 25 of whom were aged 30-39 years. Four persons from the control group showed suppressed levels of enzyme; one of these had a genetically low level, and the other three were on medication when the low levels were recorded.
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PMID:Serum cholinesterase levels of vector control workers in Trinidad, West Indies (1979-1987). 174 85

The distribution pattern of cholinesterase activity in the basal forebrain region was examined in five human brains without any history of neurologic or psychiatric disorders. Complete sets of serial sections allowed a three-dimensional reconstruction of this region. The intensity grading and the distribution pattern of the specific and non-specific cholinesterase activity was depicted diagramatically. The distribution pattern of cholinesterase activity in the supracommissural striatum demonstrated the well-known striosomal configuration, particularly in the head of the caudate nucleus. Within this nucleus caudatus the striosomes appeared connected with a subventricular zone of low acetylcholinesterase-activity. Bands of very high activity could be demonstrated from the dorsolateral and ventral areas of the caudate nucleus to the lateral border of the putamen and the commissural and subcommissural division of the ventral striatum. The distribution pattern of cholinesterase activity in the subcommissural region showed very close correlation to the cytomorphological subdivisions of the striatum as defined by Brockhaus (1942). In addition to his topographic description it was possible to define the tuberculum olfactorium and several subdivisions of the interstitial nucleus of the stria terminalis. The inhibition of non-specific esterase activity by ISO-OMPA in the globus pallidus allowed distinction between striatal and pallidal components. Three-dimensional reconstructions of the terminal islands revealed several types, which were named according to their topography as insulae substriatales, -subventriculares, -olfactoriae, -magnae, and -interstitiales. Characteristically, the core of these islands consisted of clusters of tightly packed, extremely high acetylcholinesterase-positive cells. Cholinesterase activity of the surrounding rim region ranged from negative to strongly positive depending on the position and type of the island. The findings suggest that the islands represent derivatives of the fundus striati region as defined by Brockhaus and are connected to the dorsal striatum by means of cellular bridges.
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PMID:[Cholinesterase activity in the human striatum with special consideration of the terminal islands]. 177 33

Magistral arteries of the brain and pia mater have been studied in cats 24-72 h after administration of the cholinesterase inhibitor (phosphacol, 600 mcg/kg). Cholinesterase activity in blood has been checked by means of the potentiometric titration method, and acetylcholinesterase (AChE) content in varicosities of the perivascular nervous fibers--cytophotometrically in preparations treated after Karnovsky--Roots histochemical method. Cholinesterase activity of blood homogenates in test animals is 42 +/- 10%, and acetylcholinesterase content in varicosities of the perivascular nervous fibers--23.5 +/- 2.3% in comparison to the norm. Catecholamines in adrenergic nervous elements are revealed treating them with glyoxylic acid. Distribution density (DD) of histochemically active nervous elements is determined, as well as their specific content of the mediator according to luminescent intensity (LI) of varicosities of nervous fibers. The data obtained in intact animals serve as the control. In the experiment DD and LI reach 127 +/- 9% and 154 +/- 15%, respectively, as compared to the control. Signs of the adrenergic nervous apparatus activation in the experiment reflect a compensatory reaction in response to increase of dilatatory cholinergic influences to vessels under conditions of AChE activity.
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PMID:[Reactive changes in adrenergic innervation of the cerebral arteries after activation of the cholinergic mechanisms]. 178 45

Catalytic properties of human blood erythrocyte acetylcholinesterase and horse blood serum butyrylcholinesterase immobilized and nonimmobilized in the gelatin membrane have been comparatively studied. Cholinesterase immobilization induces an increase in the Michaelis constant value and a decrease in the maximum rate value in reactions of enzymic hydrolysis of thiocholine ethers, but exerts no effect on these kinetic parameters in case of enzymic hydrolysis of indophenylacetate. The effect of reversible inhibitors: galanthamine, N-methyl-4-piperidinyl benzylate and 1,2,3,4-tetrahydro-9-aminoacridine (tacrine), as well as of irreversible inhibitors: O-ethyl-O-(4-nitrophenyl)ethyl phosphonate (armin), diisopropyl fluorophosphate (DFP), O,O-diethyl-O-(4-nitrophenyl) phosphate (paraoxon) and O,O-dimethyl-O-(2,2-dichlorovinyl) phosphate (DDVP) on immobilized cholinesterases is weaker as compared with the effect on nonimmobilized enzymes. The results obtained are discussed for the effect of immobilization on the catalytically active enzyme surface.
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PMID:[Catalytic properties of cholinesterases immobilized in a gelatin membrane]. 208 92

Cholinesterase activities were measured in plasma and in red blood cells from 6 goats after iv injection of the organophosphorus insecticide ethion at 3 different dose levels--2 mg/kg, 5 mg/kg and 10 mg/kg. Plasma levels of ethion after injection were established. At 2 mg/kg no signs of toxicity were observed and the blood cholinesterase activity remained above 65% of the control value. After administration of the higher doses the goats showed signs of severe toxicity corresponding to increased parasympathetic stimulation. Cholinesterase activities in blood were reduced to approximately 10% of the control value for the 5 mg/kg group and to approximately 5% for the 10 mg/kg group. Reactivation of cholinesterase activity in blood cells and plasma by means of pralidoxime was very efficient during the first 24 hr after administration of ethion, but was insignificant after 72 hours.
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PMID:Toxicity of ethion in goats. 230 Nov 52


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