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PubMed1995

The effect of plasma cholinesterase activity on mivacurium infusion rates.

Although mivacurium is eliminated by plasma cholinesterase, previous investigations have revealed either no relationship or limited correlation between mivacurium infusion rates (IRs) and plasma cholinesterase activity. Assuming that such a relationship should exist, we used a novel approach to better demonstrate the relationship in humans. Fourteen isoflurane-anesthetized adults underwent standard neuromuscular monitoring. Mivacurium was then infused at 1.0 micrograms.kg-1.min-1 until twitch tension stabilized. The IR was then adjusted, using the Hill equation, to produce approximately steady state 50% (n = 14) or 90% (n = 13) twitch depression. Using these values for IR and steady-state twitch depression, the IRs expected to produce 50% and 90% twitch depression (IR50 and IR90, respectively) were estimated by on nonlinear regression. Both IR50 (r2 = 0.51, P < 0.005) and IR90 (r2 = 0.48, P < 0.01) were related to plasma cholinesterase activity; the coefficient of the Hill equation did not vary with plasma cholinesterase activity. We conclude that mivacurium IRs are, as expected, influenced by the activity of the enzyme responsible for its elimination.

Adolescent↗

PubMed1999

The antiallodynic effects of intrathecal cholinesterase inhibitors in a rat model of neuropathic pain.

BACKGROUND: This study determined the effect of intrathecally administered cholinesterase inhibitors, edrophonium and neostigmine, on nerve injury-induced, touch-evoked allodynia and identified the pharmacologic characteristics of this action. METHODS: Rats were prepared with tight ligation of the left L5 and L6 spinal nerves and with lumbar intrathecal catheters fitted for long-term monitoring. Edrophonium (3, 10, 30, or 100 microg) or neostigmine (0.3, 1, 3, or 10 microg) was administered intrathecally. Tactile allodynia and motor weakness were assessed. To evaluate the pharmacologic characteristics of the activity, a muscarinic receptor antagonist or a nicotinic receptor antagonist was administered intrathecally before edrophonium or neostigmine was injected. To compare the action of subtype antagonists, the M1 muscarinic receptor antagonist pirenzepine, the M2 antagonist methoctramine, the M3 antagonist 4-DAMP (diphenylacetoxy-N-methypiperidine), and the M4 antagonist tropicamide were administered intrathecally before cholinesterase inhibitors were injected. RESULTS: Intrathecal edrophonium or neostigmine produced a dose-dependent antagonism of the touch-evoked allodynia. Neostigmine resulted in a moderate effect on motor weakness at doses of 3 and 10 microg. Pretreatment with intrathecal atropine but not mecamylamine yielded a complete antagonism of the effects of the cholinesterase inhibitors. In addition, antiallodynia produced by edrophonium (100 microg) was reversed by pretreatment with methoctramine, 4-DAMP, tropicamide, and pirenzepine. In the neostigmine (10 microg) group, only the M1 antagonist pirenzepine had a moderate effect on reversal of increased allodynic threshold. CONCLUSIONS: These experiments suggest that intrathecal edrophonium or neostigmine produces an antagonism on touch-evoked allodynia at the spinal level in a rat model of neuropathic pain and that the antiallodynic action of cholinesterase inhibitors is probably mediated by a spinal muscarinic system, especially at the M1 receptor subtype.

Animals↗

PubMed2000

Cholinesterase inhibitor therapy stabilizes symptoms of Alzheimer disease.

Cholinesterase inhibitors tested in clinical trials in Europe, the United States, and Japan include fewer than 10 drugs; however, most of these compounds have advanced to clinical phase III trials. Based on results related to a population of more than 8,000 patients, we conclude that several of these compounds have shown significant clinical efficacy and safety in the treatment of Alzheimer disease. There are, however, differences with regard to side effects. The major clinical effect is stabilization of cognitive function during a 6- to 12-month period with an improvement of behavioral symptoms. The long-term effect of cholinesterase inhibitors extending to a 2-year period was reported. Future applications of these drugs include treatment of other types of dementias such as Lewy bodies dementia, vascular dementia, and Down syndrome dementia. The combination of cholinesterase inhibitors with estrogens, antioxidants, and anti-inflammatories may represent a further improvement of the therapy. From an economical point of view, treatment with cholinesterase inhibitors is not cost neutral.

Aged↗

PubMed1986

Serum cholinesterase in patients with fatty liver.

In search of a practical biochemical test that will reflect hepatic steatosis, we assessed the significance of serum cholinesterase activity in 48 patients with nonalcoholic fatty liver, 16 obese subjects without fatty liver, 30 cases of chronic persistent hepatitis, 38 cases of chronic active hepatitis, and 20 cases of liver cirrhosis. Increased cholinesterase activity was observed in nonobese as well as obese patients with fatty liver, whereas obese subjects without fatty liver showed levels in the upper normal range. When we set a cutoff level above the upper normal limit, half of the patients with fatty liver showed values above it, with only a few overlaps with other patients. When obese patients with fatty liver took a low-caloric diet, cholinesterase activity decreased, clearly reflecting improvement of hepatic steatosis. Thus, measurement of cholinesterase activity is of diagnostic value and an alternative to computed tomography in hepatic steatosis, and will provide a practical measure for the assessment of effects during follow-up.

Cholinesterases↗

PubMed1986

Biological monitoring of agricultural workers exposed to pesticides: I. Cholinesterase activity determinations.

An estimated 4 to 5 million persons work in agriculture; within this sector, mixers, loaders, applicators, and other workers who directly handle agricultural chemicals are at highest risk for pesticide-related illnesses. Among field workers, seasonal workers engaged in certain cultivation and harvesting operations are also at risk of exposure to pesticide residues. Biological screening for agricultural workers is limited at present to pesticide mixers, loaders, and applicators, and consists almost exclusively of measurements of cholinesterase activity to estimate inhibition by organophosphate and carbamate compounds. We review here the measurement and interpretation of cholinesterase activity in occupationally exposed populations and the correlation between cholinesterase activity and symptoms of acute and chronic illness among agricultural workers. The only state to mandate medical surveillance for agricultural workers is California: criteria for surveillance, baseline cholinesterase determination, periodicity of testing, and criteria for removal from and return to work are described, and alternative approaches for screening and clinical evaluations are discussed.

Adult↗

PubMed1980

Localization of cholinesterase in Pseudomonas aeruginosa strain K.

The inducible cholinesterase of Pseudomonas aeruginosa strain K (ATCC 25102) degraded propionylcholine, acetylthiocholine, acetylcholine and acetyl-beta-methylcholine at a high rate and butyrylcholine and succinylcholine at very low rates. The localization of the enzyme in the periplasmic space was indicated by a similar rate of acetylcholine degradation by intact cells or their extracts, by release of cholinesterase together with alkaline phosphatase into the culture medium during cell growth in a low phosphate-containing medium, by liberation of cholinesterase and alkaline phosphatase during lysozyme-induced conversion of cells to spheroplasts and by freezing and thawing. Threatment of cells with diazo-7-amino-1,3-naphthalenedisulphonic acid, which inactivates surface-located enzymes, abolished most of the cholinesterase and 5'-nucleotidase activities.

Alkaline Phosphatase↗

PubMed1977

Hereditary cholinesterase deficiency: a report of a family with two rare genotypes.

Cholinesterase deficiency was detected in a young girl following an episode of postanesthesia apnea. Subsequently, plasma and serum cholinesterase levels and dibucaine numbers were determined on blood samples from 56 members of her extended family. Including the proband, three individuals were identified with severe cholinesterase deficiency and 12 were found to have mild abnormalities. The occurrence of two genetic variants regulating cholinesterase production, the "silent" gene and the atypical enzyme, is postulated to account for the unusual pattern of inheritance in this family. Screening family members of confirmed cases is essential to prevent the potentially fatal consequences of this hereditary disorder.

Adolescent↗

PubMed1978

Prolonged apnoea after suxamethonium: an analysis of the first 225 cases reported to the Danish Cholinesterase Research Unit.

During the last 4 years, 225 patients have been referred to the Danish Cholinesterase Research Unit following an episode of prolonged apnoea after suxamethonium. Fourteen patients (6.2%) were found to have a low serum cholinesterase activity due to an acquired deficiency (for instance, liver disease, chronic debilitating disease or carcinoma). One hundred and forty-eight patients (65.8%) had an inherited abnormal serum cholinesterase, and 105 of these patients (46.7%) were homozygous for the atypical enzyme (E1 Ea1). The mean period of apnoea in this latter group was 92 min (range: 25--240). Seventeen patients (7.6%) were heterozygous for the normal and the atypical enzyme (Eu1 Ea1), with a mean apnoea period of 25 min (range: 7--60 min). Twelve patients were found to be heterozygous for the atypical and the silent gene (E(a)1 E(s)1). The mean period of apnoea was 126 min (range: 45--210 min). Fourteen patients had other rare genotypes. The longest mean period of apnoea (170 min, range: 70--330) was found in patients homozygous for the silent gene (Es1 Es1). The silent gene and the fluoride-resistant gene were found in 8.9% and 2.7% of the patients, respectively. In 63 patients (28.1%) both the type and quantity of serum cholinesterase were normal. In 34 of these patients (15.2%), the prolonged apnoea was due to other causes; for example, suxamethonium overdose, hyperventilation and central as well as peripheral respiratory depression. However, in the other 29 patients (12.9%), the reason for the prolonged apnoea could not be established. The possibility therefore exists that these cases represent unknown genotypes.

Adolescent↗

PubMed1990

The effect of bambuterol (carbamylated terbutaline) on plasma cholinesterase activity and suxamethonium-induced neuromuscular blockade in genotypically normal patients.

Bambuterol (the bisdimethylcarbamate prodrug of terbutaline) is a new bronchodilator with a prolonged duration of action due to its inhibition of plasma cholinesterase during metabolism. The effect of bambuterol on suxamethonium-induced neuromuscular blockade was studied in 10 patients undergoing elective laparotomy. Thirty mg of bambuterol was given 2 h before anaesthesia, which was performed with thiopentone, fentanyl, halothane and nitrous oxide in oxygen. Neuromuscular function was monitored using supramaximal train-of-four stimulation of the ulnar nerve and a force displacement transducer. Suxamethonium 1 mg.kg-1 was given i.v. for endotracheal intubation. Plasma cholinesterase activity was measured before and after intake of bambuterol and during anaesthesia. The results from the 10 patients were compared with those of 41 patients not given bambuterol but otherwise studied during the same conditions. Following bambuterol, all patients had a significant decrease of plasma cholinesterase activity (P less than 0.001) and the suxamethonium-induced blockade was 3-4 times prolonged compared to patients not given bambuterol (P less than 0.001). Five patients with very low plasma cholinesterase activity developed a long-lasting phase II block.

Adult↗

PubMed1989

Cholinesterases from flounder muscle. Purification and characterization of glycosyl-phosphatidylinositol-anchored and collagen-tailed forms differing in substrate specificity.

Flounder (Platichthys flesus) muscle contains two types of cholinesterases, that differ in molecular form and in substrate specificity. Both enzymes were purified by affinity chromatography. About 8% of cholinesterase activity could be attributed to collagen-tailed asymmetric acetylcholinesterase sedimenting at 17S, 13S and 9S, which showed catalytic properties of a true acetylcholinesterase. 92% of cholinesterase activity corresponded to an amphiphilic dimeric enzyme sedimenting at 6S in the presence of Triton X-100. Treatment with phospholipase C yielded a hydrophilic form and uncovered an epitope called the cross-reacting determinant, which is found in the hydrophilic form of a number of glycosyl-phosphatidylinositol-anchored proteins. This enzyme showed catalytic properties intermediate to those of acetylcholinesterase and butyrylcholinesterase. It hydrolyzed acetylthiocholine, propionylthiocholine, butyrylthiocholine and benzoylthiocholine. The Km and the maximal velocity decreased with the length and hydrophobicity of the acyl chain. At high substrate concentrations the enzyme was inhibited. The p(IC50) values for BW284C51 and ethopropazine were between those found for acetylcholinesterase and butylcholinesterase. For purified detergent-soluble cholinesterase a specific activity of 8000 IU/mg protein, a turnover number of 2.8 x 10(7) h-1, and 1 active site/subunit were determined.

Acylation↗

PubMed1985

Cholinesterases in single nerve cells isolated from the locus ceruleus and from nucleus of the facial nerve of the rat: a microgasometric study.

Cholinesterase activity in single nerve cell bodies isolated from the locus ceruleus and nucleus of the facial nerve of the rat was analyzed by the microgasometric method. Acetylcholinesterase activity is about the same in both types of cells. Nonspecific cholinesterase is present in noradrenergic cells of the locus ceruleus but not in the cholinergic cells of the nucleus of the facial nerve. The total activity of cholinesterases and the activity of acetylcholinesterase in nerve cell bodies isolated from the locus ceruleus remains practically unchanged from the tenth postnatal day until the age of 24 months. Depletion of noradrenaline by a high dose of reserpine does not influence the total activity of cholinesterases in nerve cell bodies of locus ceruleus.

Acetylcholinesterase↗

PubMed1957

The enzymatic hydrolysis of imidazoleacryloylcholine (murexine) and imidazolepropionylcholine (dihydromurexine) by various cholinesterases.

Several choline esters, including the imidazoleacryloyl and imidazolepropionyl compounds, have been hydrolysed by cholinesterases from various sources. The imidazolepropionyl ester was metabolized by cholinesterases obtained from human plasma, ox spleen, ox serum, and guinea-pig liver, but not by rat liver or bovine red cell cholinesterase. It is suggested the imidazolepropionylcholine or a closely related ester might be the natural substrate for "non-specific" cholinesterase.

Acetylcholinesterase↗

PubMed2005

Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials.

OBJECTIVES: Pharmacological treatment of Alzheimer's disease focuses on correcting the cholinergic deficiency in the central nervous system with cholinesterase inhibitors. Three cholinesterase inhibitors are currently recommended: donepezil, rivastigmine, and galantamine. This review assessed the scientific evidence for the recommendation of these agents. DATA SOURCES: The terms "donepezil", "rivastigmine", and "galantamine", limited by "randomized-controlled-trials" were searched in Medline (1989-November 2004), Embase (1989-November 2004), and the Cochrane Database of Systematic Reviews without restriction for language. STUDY SELECTION: All published, double blind, randomised controlled trials examining efficacy on the basis of clinical outcomes, in which treatment with donepezil, rivastigmine, or galantamine was compared with placebo in patients with Alzheimer's disease, were included. Each study was assessed independently, following a predefined checklist of criteria of methodological quality. RESULTS: 22 trials met the inclusion criteria. Follow-up ranged from six weeks to three years. 12 of 14 studies measuring the cognitive outcome by means of the 70 point Alzheimer's disease assessment scale--cognitive subscale showed differences ranging from 1.5 points to 3.9 points in favour of the respective cholinesterase inhibitors. Benefits were also reported from all 12 trials that used the clinician's interview based impression of change scale with input from caregivers. Methodological assessment of all studies found considerable flaws--for example, multiple testing without correction for multiplicity or exclusion of patients after randomisation. CONCLUSION: Because of flawed methods and small clinical benefits, the scientific basis for recommendations of cholinesterase inhibitors for the treatment of Alzheimer's disease is questionable.

Alzheimer Disease↗

PubMed1960

An assessment of the value of serum cholinesterase as a liver function test and in the diagnosis of jaundice.

This report assesses the value of cholinesterase (ChE) activity as an indicator of liver function and analyses its usefulness in the diagnosis of jaundice. A rapid method of determination has been used, and alterations in ChE activity in conditions other than liver disease have been studied to permit a fuller and more accurate survey of its value as a liver function test. The level of serum cholinesterase activity remains constant under normal circumstances, and follows the pattern of protein metabolism, falling in catabolism and rising in anabolism.In hepatocellular disease cholinesterase activity is lowered. Very low levels in cirrhosis with jaundice indicate a grave prognosis. Normal levels are usual in post-hepatic jaundice unless complicating factors are present, such as cholangitis or liver metastases. Serum cholinesterase is useful both as a liver function test and in the diagnosis of jaundice provided consideration is given to the other factors which affect the level of activity of the enzyme.

Cholangitis↗

PubMed1994

A PCR based method to determine the Kalow allele of the cholinesterase gene: the E1k allele frequency and its significance in the normal population.

The Kalow allele for cholinesterase is a quantitative variant of the usual gene and has been shown to result from a single base pair change in the DNA. A new method based on the polymerase chain reaction to distinguish Kalow alleles of the cholinesterase gene was developed. Using the amplification refractory mutagenesis system, two different reactions distinguished the presence of a guanine (normal E1u allele) from that of an adenine (Kalow E1k allele) at nucleotide 1615 within the coding sequences of the gene. The frequency of the Kalow allele in our sample of 51 persons was determined to be 20%. The mean total cholinesterase activity in heterozygotes was 90% of that in persons who typed as E1uE1u homozygotes. Two E1kE1k homozygotes were identified and their cholinesterase activities were the two lowest measured.

Adult↗

PubMed1984

Changes in acetylcholinesterase and cholinesterase activities in rat pancreas during postnatal development. Lack of relation with muscarinic receptor maturation.

This study was undertaken to establish if there is a correlation between the ontogenesis of cholinesterase activities and the cholinergic muscarinic receptors in the development of rat pancreas. Two different cholinesterase activities were detected in the pancreas: a true acetylcholinesterase and a pseudocholinesterase. The ratio of acetylcholinesterase to total cholinesterase activities varied as a function of age. Acetylcholinesterase and total cholinesterase specific activities (units per milligram protein) decreased sharply at weaning. When expressed on a DNA basis, both activities decreased constantly until age 30 days to increase slightly thereafter. However, a correlation could not be established between the development of acetylcholinesterase activity and the muscarinic receptors.

Acetylcholinesterase↗

PubMed1980

Effect of indomethacin on the histological structure and cholinesterase activity of taste buds.

The present work was undertaken to study the effect of indomethacin on the histological structure and cholinesterase activity of taste buds. 16 adult rabbits were divided into four groups; 2 animals of each group were given a daily oral dose of indomethacin and the other 2 animals were used as controls. The animals were sacrificed at 7, 12, 17 and 30 days, respectively. The areas containing circumvallate and foliate papillae were excised for the study of their histological structure and cholinesterase activity. Administration of indomethacin was followed by a decrease in cholinesterase activity and a shrinkage of the reactive zones of the perigemmal, intragemmal and subgemmal plexuses; the cholinesterase activity eventually disappeared on the 17th day. On the 30th day, it reappeared in the above-mentioned sites. The taste buds did not show any degenerative changes and were similar to those of the controls. The significance of these findings is discussed.

Animals↗

PubMed1989

Innervation and cholinesterase activity in the skin of albino and desert rats.

The distribution of nerves and cholinesterase activity in the skin of the desert and albino rats has been studied using both histological and histochemical techniques. In the desert rat, the skin was richly innervated. Specific cholinesterase was concentrated in the nervous network of the dermis and around the hair follicles, in the nerve bundles of the dermis, in perivascular nerves, in fine intra-epithelial nerves and in sensory end organs in the junctional area between the dermis and epidermis. In the albino rat, specific cholinesterase was concentrated in the sebaceous glands. The positive cholinesterase activity that was seen in the desert rat in intra-epithelial nerves, and in dermal and hair follicle networks could not be demonstrated.

Animals↗