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)

A 40-year-old white woman underwent amniocentesis for advanced maternal age at 15.4 weeks gestation. Fetal chromosome analysis demonstrated two distinct cell lines: [46,XX,t(1;19)(p11;p11)]--10%; and [47,XX,t(1;19)(p11;p11) + der(1)t(1;19)(p11;q11)]--90%. The latter karyotype was trisomic for both 1q and 19p. The mother carried the balanced translocation; the father had a normal karyotype. Amniotic fluid alpha-fetoprotein level was elevated and an acetylcholinesterase band was detected. Level II ultrasonography at 17 and 24 weeks revealed several abnormalities, including a large facial cleft and a probable facial teratoma and intracranial tumor. Autopsy following pregnancy termination confirmed the presence of both. Chromosome evaluation of 172 metaphases of both the epignathus and the intracranial teratoma demonstrated a predominance of the cell line with 47 chromosomes (166/172 = 96.5%), while from nonteratoma tissue (lung, liver, skin, and brain) only the balanced karyotype was detected. These observations suggest that the chromosomal imbalance is instrumental in the etiology of the teratoma.
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PMID:An unusual mosaic karyotype detected through prenatal diagnosis with duplication of 1q and 19p and associated teratoma development. 138 56

Activities of enzymes cholinesterase (ChE) and carboxylesterase (CaE) were assayed in serum, liver microsomes and three regions of brain, viz; cerebrum, cerebellum and brain stem (with mid brain) in male albino rats at 0.5 and 2 h periods after administration of 1/2 LD 50 dose of soman (0.22 mg/kg) intraperitoneally in olive oil as vehicle. At 0.5 h, in serum, ChE activity declined to 33% of its initial level whereas CaE activity was almost completely inhibited. However, in the liver microsomes at this period, ChE activity was greatly inhibited (18% of initial level) whereas CaE activity was nearly unaffected. At 2 h period, both the enzymes in the serum were almost completely inhibited. In the brain regions (excepting in cerebellum), both the enzymes were nearly similarly inhibited (by 55% to 65% of the initial level) at both the periods. The time related differential response of these two beta-esterases in acute soman intoxication probably occurred in the peripheral tissues like blood and liver but not in the CNS.
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PMID:Effect of soman administration on beta-esterases in blood, liver microsomes and brain regions of rats. 147 52

Heptastigmine is a new long acting cholinesterase inhibitor that affects behaviour in a number of cognitive tests in animals. We have studied its pharmacokinetics in rats: plasma kinetics were evaluated after single intravenous dose (2 mg/kg), intramuscular (4 mg/kg) and oral (4 and 8 mg/kg) administration. Tissue distribution (heart, liver, kidney and brain) was studied after single intramuscular (4 mg/kg) and oral (8 mg/kg) administration. Plasma and tissue kinetics were also investigated after repeated oral doses (8 mg/kg b.i.d. for 7 days). Heptastigmine levels in plasma and tissues were determined using an HPLC method with an electrochemical detector. After a single dose, heptastigmine remained for a long time in plasma (the terminal half-life was about 12 h), distributed widely in tissues (the volume of distribution was about 61) and brain concentrations were very high (4-22 times those found in plasma). After repeated oral doses, the drug levels increased in plasma and, to a lesser extent, in liver and kidney.
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PMID:Pharmacokinetics of heptastigmine in rats. 163 92

The N-myc cellular oncogene is frequently amplified and expressed at a high level in neuroectodermal tumor cells such as neuroblastoma and retinoblastoma. We examined N-myc expression in NCB-20 hybrid (N18TG2 neuroblastoma x embryonic Chinese Hamster brain) cells. After five days of culture, cells treated with 1 mM db cAMP show extensive neurite outgrowth and secrete acetylcholinesterase into the media at a level three times higher than untreated control. In situ hybridizations, dot blots, and Northern analyses reveal four- to eight-fold higher levels of N-myc mRNA in the treated, differentiated cells than in the untreated, undifferentiated controls. Our results show that the highly differentiated state is not incompatible with a high level of N-myc mRNA.
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PMID:Increased N-myc mRNA expression associated with dibutyryl cyclic AMP induced neuroblastoma differentiation. 256 Apr 82

The distribution, metabolism, and pharmacokinetics of physostigmine (Phy) and the time course of butyrylcholinesterase (BuChE) in plasma and cholinesterase (ChE) activity in brain and muscle and their relationship to Phy concentration were described after oral administration of 3H-Phy (650 micrograms kg-1) to rats. Physostigmine concentration vs time data was analyzed by nonlinear computer fitting program using one-compartment model. The absorption rate constant (ka) and elimination rate constant (ke) were found to be 0.1 +/- 0.07 min-1 and 0.036 +/- 0.024 min-1, respectively. Cpmax and tmax were 3.3 ng ml-1 and 16 min. The clearance (C1) was found to be 80.9 ml min-1kg-1. Half-life of Phy in brain, muscle, and liver were 33.4 min, 22.5, and 28 min, respectively. The bioavailability (F) was calculated to be 0.02 and the extraction ratio was found to be 0.98 indicating the 'first pass' effect. Butyrylcholinesterase activity in plasma was 76 per cent at 15 min and this activity did not change significantly up to 120 min. However, Phy concentration in plasma was very low; 2.89 ng ml-1 at 15 min and declined to 0.71 ng ml-1 at 90 min. Physostigmine concentration in brain peaked at 22 min to 2.85 +/- 1.09 ng g-1 and declined to 0.33 +/- 0.11 ng g-1 at 60 min. Cholinesterase activity in brain was 96 per cent, 82 per cent and 89 per cent at 10, 45, and 120 min, respectively. Physostigmine concentration in muscle was very low and the ChE activity in the muscle was 66.4 per cent of control at 45 min. The time course of Phy metabolism indicated that at 5 min most of the RA in the tissues was due to metabolites accounting for 94.6 per cent in plasma, 90 per cent in liver, 79.8 per cent in brain and 86.3 per cent in muscle. M1 appeared to be the major metabolite followed by eseroline. The results showed extremely low concentrations of Phy (200 times less in plasma and 350 times less in brain) after oral administration compared to our previous studies with the same dose after i.m. administration.
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PMID:Pharmacokinetics and pharmacodynamics of physostigmine in the rat after oral administration. 270 18

Radiation inactivation is a method to determine the apparent target size of molecules. In this report we examined whether radiation inactivation of various enzymes and brain receptors is influenced by the preparation of samples preceding irradiation. The apparent target sizes of endogenous acetylcholinesterase and pyruvate kinase from rat brain and from rabbit muscle and benzodiazepine receptor from rat brain were investigated in some detail. In addition the target sizes of alcohol dehydrogenase (from yeast and horse liver), beta-galactosidase (from Escherichia coli), lactate dehydrogenase (endogenous from rat brain), and 5-HT2 receptors, acetylcholine muscarine receptors, and [35S] butyl bicyclophosphorothionate tertiary binding sites from rat brain were determined. The results show that apparent target sizes are highly influenced by the procedure applied for sample preparation before irradiation. The data indicate that irradiation of frozen whole tissue as opposed to lyophilized tissue or frozen tissue homogenates will estimate the smallest and most relevant functional target size of a receptor or an enzyme.
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PMID:The apparent target size of rat brain benzodiazepine receptor, acetylcholinesterase, and pyruvate kinase is highly influenced by experimental conditions. 284 37

A new method has been described for removing a very small number of contaminating astrocytes in neuronal cultures (derived from the septal-diagonal band region of 17-day-old embryonic rat brain) grown in a chemically defined medium. The proportion of these glial fibrillary acidic protein (GFAP)-positive cells was usually less than 1.5% up to 10 days, but thereafter their number increased rapidly reaching 10-15% by 22 days in vitro. A prolonged exposure to normally used concentration of cytosine arabinoside (Ara-C; 10 microM) was toxic to both astroglial and neuronal cells, while a brief treatment (48 h) with a low level (4 microM) of Ara-C failed to eliminate these astrocytes, as judged by glutamine synthetase activity and GFAP-positive cell count. However, these quiescent astroglial cells could be easily eliminated if they were induced to proliferate by epidermal growth factor before exposure to Ara-C. The combined treatment with these agents had no effect on the number of acetylcholinesterase-positive cells, and on the development of cholinergic and GABA-ergic neurons, as measured in terms of choline acetyltransferase and glutamate decarboxylase activity, respectively.
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PMID:A novel way of removing quiescent astrocytes in a culture of subcortical neurons grown in a chemically defined medium. 290 25

Light- and electron-microscopic enzyme cytochemistry was used to localize acetylcholinesterase (AChE) activity in the synganglion (brain) of the tick Dermacentor variabilis. High AChE activity was observed throughout the neuropil as well as adjacent to most neuronal perikarya. Intracellular activity was not observed by light microscopy. By electron microscopy, reaction product was localized at the plasma membrane of glia and neurons. Enzyme activity was not associated with the olfactory globuli neurons. In other types of neurons, small amounts of reaction product were observed in the Golgi apparatus and nuclear envelope. Large neurosecretory neurons contained activity that appeared to be associated with deep invaginations of the plasma membrane as well as intracellular membranes. AChE activity was also associated with processes of both neurons and glia. In most peripheral nerves AChE activity was associated with virtually all axons. Clearly then, AChE is associated with glia and non-cholinergic neurons as well as with presumed cholinergic neurons. The widespread localization and large amounts of AChE in the tick brain exceeds that reported for other invertebrates and vertebrates. As has been suggested for other animals, AChE in the tick brain may have functions in addition to its known role in cholinergic neurotransmission.
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PMID:Ultrastructural localization of acetylcholinesterase in the synganglion of the tick, Dermacentor variabilis (Say). 366 8

Carboxylesterases (EC 3.1.1.1) of chicken brain were investigated by applying kinetic analysis of organophosphorus inhibition. By iterative elimination of exponential inhibition curves and by sequential inhibition experiments using a combination of two organophosphorus inhibitors, 11 different carboxylesterases of chicken brain were characterized with respect to their phenyl valerate-hydrolyzing activity (milliunits per gram of brain) and their inhibition by O,O-diethyl O-4-nitrophenyl phosphate (Paraoxon), O,O-diisopropylphosphorofluoridate, and N,N'-diisopropylphosphorodiamidic fluoride (Mipafox). The bimolecular inhibition rate constants (liters . mole-1 . min-1) were calculated for the 11 enzymes and 3 organophosphorus compounds. The corresponding data for acetylcholinesterase (EC 3.1.1.7) in chicken brain were determined. The importance of inhibition rate constants for the development of acute cholinergic symptoms, delayed neurotoxicity, and atypical organophosphate effects is shown.
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PMID:Inhibition of brain carboxylesterases by neurotoxic and nonneurotoxic organophosphorus compounds. 686 14

1. Endosulfan insecticide is a polychlorinated compound used for controlling a variety of insects; it is practically water-insoluble, but readily adheres to clay particles and persists in soil and water for several years. Its mode of action involves repetitive nerve-discharges positively correlated to increase in temperature. This compound is extremely toxic to most fish and can cause massive mortalities. In fish, it causes marked changes in Na and K concentrations, decrease in blood Ca(2+) and Mg levels and inhibits Na, K and Mg-dependent ATPase (in brain). 2. Bioaccumulation of endosulfan is reported for marine animals; however, freshwater animals (e.g., crayfish) accumulate it to some extent, but they lose the compound rapidly during depuration. Endosulfan is generally less toxic to aquatic invertebrates than fish. However, it causes decreases in adenylate energy charge, oxygen consumption, hemolymph amino acids, succinate dehydrogenase, heart-beat (mussel) and altered osmoregulation. 3. Generally, mammals are less susceptible to endosulfan's toxicity than aquatic animals. The majority of studies conducted on laboratory mammals can be summarized. (a) Neurotoxicity: male rats are more sensitive than females to endosulfan, which decreases brain and plasma acetylcholinesterase activity. Endosulfan I (a metabolite) causes a significant change in norepinephrine, 5-HT and GABA. (b) Renal toxicity: inhibition of MFOs activity was noticed in rats; other effects included changes in proximal convoluted tubules and necrosis of the tubular epithelium. (c) Hepatotoxicity: chemically-induced aminopyrine N-demethylase and aniline hydrolase were found in rat liver, and reduction in the glycogen level occurred. (d) Hematologic toxicity: endosulfan exposure resulted in a significant decrease in the level occurred. (d) Hematologic toxicity: endosulfan exposure resulted in a significant decrease in the erythrocyte glutathione reductase, hemoglobin amount, RBC number and mean corpuscular volume. 4. Respiratory toxicity: involved dyspnea, acute emphysema, cyanosis and hemorrhages in teh interalveolar portions of rat's lungs. 5. Biochemical: in rats, endosulfan caused increased glucose-6-phosphate dehydrogenase activity, blood glucose level, phospholipid contents of the microsomal and surfactant system, and profoundly induced the activity of alcohol dehydrogenase and cytosolic glutathione S-transferases. It also decreased significantly Na+, K+ and Mg(2+) ATPases, plasma calcium level and alkaline phosphatase in the intestinal epithelium. 6. Immunologic toxicity: rat serum antibody titer to tetanus toxin, IgG, IgM and gammaglobulins were significantly reduced. 7. Reproductive toxicity: degenerative changes in the seminiferous epithelium, induction of the rate-limiting enzyme in testosterone production (3beta-hydroxysteroid transferase and 17 beta-hydroxysteroid transferase), histological changes in reproductive organs, testicular atrophy and the occurrence of ovarian cysts were noticed in rat. Reduction in the weight of secondary sex organ was also observed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Bioaccumulative potential and toxicity of endosulfan insecticide to non-target animals. 790 Sep 59


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