Pseudocholinesterase Activity Research Articles

Ultrastructural localization of acetylcholinesterase in the guinea pig pineal gland

The ultrastructural localization of acetylcholinesterase (AChE) activity in guinea pig pineal gland was studied using the copper-glycine procedure. A small number of pinealocytes and bundles of unmyelinated nerve fibers were labeled by the AChE reaction. The AChE-positive pinealocytes were located near blood vessels and distributed in small groups. The AChE reaction product was localized in the perinuclear cistern, in the cisternae of the endoplasmic reticulum (ER), and in the saccules of the Golgi apparatus. These findings suggest that the AChE-positive pinealocytes synthesize AChE. The AChE reaction product was also seen in the intercellular space between pinealocyte processes. Besides pinealocytes, AChE activity was localized on the axolemma of myelinated and unmyelinated nerve fibers and in the basement membrane surrounding unmyelinated nerve fibers. Pseudocholinesterase activity was confined to Schwann cells, which showed the reaction product in their perinuclear cistern, in the cisternae of the ER, and on the plasmalemma.

Determination of Pseudocholinesterase Activity in the Gingival Crevicular Fluid, Saliva, and Serum from Patients with Juvenile Periodontitis and Rapidly Progressive Periodontitis

By use of a spectrophotometric method, pseudocholinesterase (PCE) activities were determined in gingival crevicular fluid (GCF), saliva, and serum from patients with juvenile periodontitis (JP) and rapidly progressive periodontitis (RPP) and from controls. The PCE activity in the GCF samples was 181 +/- 48 U/L in the JP group, 588 +/- 135 U/L in the RPP group, and 88.5 +/- 29.1 U/L in the control group. Saliva PCE activity levels were 9.1 +/- 1.7 U/L in the JP group, 21.8 +/- 4.5 U/L in the RPP group, and 12.7 +/- 0.8 U/L in the control group. GCF contained a higher PCE activity than saliva but a lower one than that of serum. The RPP group had a significantly higher PCE activity in both the GCF and saliva samples. No significant differences could be found regarding serum enzyme levels. Also, no significant correlations were present between biochemical values and the severity of periodontal disease. GCF may be an important source for the PCE content of saliva. It is suggested that the increased PCE activity seen in RPP patients might be caused by either the direct production of esterases by bacteria or the induction of esterases during periodontal destruction.

Increase in the Activities of Plasma Pseudocholinesterase Dependent on the Blood Glucose Level and Its Relation to the Hypersensitivity to Acetylcholine in Striated Muscles of KK-CAy Mice with Diabetes

Acetylcholinesterase activity and pseudocholinesterase activity were examined in plasma and in striated muscles (whole heart and diaphragm muscles) of diabetic KK-CAy mice. Both activities of acetylcholinesterase in heart muscle and pseudocholinesterase in plasma were significantly increased in diabetic KK-CAy mice compared to pre-diabetic KK-CAy mice. Both acetylcholinesterase and pseudocholinesterase activities in skeletal muscle were not changed by the diabetic state. The increases in activity of plasma pseudocholinesterase was significantly correlated to the increase in blood glucose level in alloxan-, streptozotocin (STZ)-diabetic ddY mice and diabetic KK-CAy mice. The increase was not correlated to the body weight in non-diabetic female-KK-CAy mice. Furthermore, the activity of heart acetylcholinesterase was significantly correlated with the activity of plasma pseudocholinesterase (r=0.79, P<0.01). The activities of acetylcholinesterases in heart muscles from STZ- and alloxan-diabetic ddY mice also tended to increase. The hypersensitivity of the pulse rate to a low dose (1 mg/kg) of acetylcholine was correlated to the activity of plasma pseudocholinesterase (r=-0.51, P<0.05). These results demonstrate that the activities of plasma pseudocholinesterase were increased by the diabetic state being associated with the increasing alteration of cardiac sensitivity to acetylcholine in the whole body.

Pseudocholinesterase Activity in Human Cerebrospinal Fluid

In view of conflicting data concerning metabolism of ester type local anesthetics in CSF, the authors collected a sample of CSF from a series of 10 patients scheduled for spinal anesthesia. In addition, 4 patients with a history of recent bleeding into the CSF who were under general anesthesia had a CSF sample collected as well as 3 ml of venous blood. In all samples, pseudocholinesterase (PCHE) activity and dibucaine numbers (DN) were determined.

Determination of succinylcholine hydrolytic enzyme activity in human plasma

Succinylcholine is frequently employed in surgical procedures as a pre-anaesthetic. However, the lack of existing metabolic activity for this compound in some individuals entails a substantial risk. Normally, the risk is assessed indirectly throught the measurement of pseudocholinesterase activity using other substrates, such as acetylcholine, rather than the agent itself. Thus, a method was devised to assess directly the hydrolysis of succinylcholine in human plasma samples. This method was applied to plasma samples derived from healthy men, healthy women, pregnant women and patients with silent pseudocholinesterasaemia.

Serum cholinesterase activity in infantile and juvenile spinal muscular atrophy.

Serum acetylcholinesterase (AChE) and pseudocholinesterase (ChE) activity in infantile and juvenile spinal muscular atrophy (SMA) was determined. The total AChE activity was either normal or decreased in the childhood SMA (Type 1), the other SMA groups and disease controls (ALS, X-linked SMA). In the majority of SMA Type 1 cases (6/7 tested) an absence of the asymmetric A12 form was found. This was accompanied by changes in the other asymmetric and globular forms. The latter was, however, not specific for SMA Type 1 cases. The ChE activity was increased in the majority of SMA cases as well as disease controls. The asymmetric A12 ChE form was increased in all SMA Type 3 cases, the values of this form in SMA Type 1 was variable. A change in the ChE globular forms in SMA Type 1 and SMA Type 2 was a frequent finding. It is suggested that the absence of the asymmetric A12 AChE form in SMA Type 1 arises because of muscle cell immaturity and undeveloped muscle-nerve interactions. The reason of ChE changes is obscure.

Pseudocholinesterase Activity in Human Cerebrospinal Fluid

Pseudocholinesterase (PCHE) activity and dibucaine numbers (DN) in the cerebrospinal fluid (CSF) and plasma of 10 ASA physical status 1 and 2 patients were measured using a kinetic method. CSF had a mean PCHE activity of 0.018 +/- 0.013 unit/ml with a DN of 59 +/- 4. Whereas, PCHE activity and DN in the plasma were 0.960 +/- 0.12 units/ml and 84 +/- 3, respectively. We also measured PCHE activity and DN in the CSF and plasma of 4 patients in whom there was a recent history of intraventricular bleeding. These patients had a CSF PCHE activity of 0.340 +/- 0.07 units/ml (DN = 78 +/- 3) and a plasma PCHE activity of 0.950 +/- 0.10 units/ml (DN = 82 +/- 2). Our data show that there is a low activity of PCHE in CSF, 1/20-1/100th that of plasma. Our data also show that PCHE activity increased to 1/4 to 1/2 that of plasma in CSF of patients with bleeding into CSF.

Clinical signs and biochemical changes in calves caused by injection of ivermectin.

Eight-month-old Jersey bull calves given ivermectin intravenously or subcutaneously showed signs of depression, ataxia, difficulty in breathing, tachycardia, salivation, diarrhoea, miosis, and an increase in pseudocholinesterase activity. The clinical signs were severe in calves given the drug intravenously. The findings suggest that the cholinergic nervous system may be involved in some of the adverse effects of ivermectin observed in calves.

Origin of butyrylcholinesterase in the lateral geniculate nucleus of tree shrew

We examined the distribution and possible origins of pseudocholinesterase activity within the lateral geniculate nucleus (LGN) of the tree shrew. Butyrylcholinesterase (BuChE) activity was spread diffusely throughout the LGN and not localized to neuronal perikaryon. Lesions of the LGN eliminated this BuChE activity while not affecting acetylcholinesterase (AChE) activity; however, removal of retinal input by unilateral ocular enucleations failed to affect the BuChE activity within the denervated layers of the LGN. This lack of effect suggests that, unlike the macaque monkey, retinal terminals within the LGN of tree shrew are not the source of BuChE. Thus, in the tree shrew LGN it appears that BuChE is not metabolically related to or dependent upon AChE nor does it originate from retinal sources, but rather BuChE appears to represent an enzyme that is endogenous to the LGN.

Hormonal regulation of pseudocholinesterase activity in cultured rat hepatocytes.

Plasma pseudocholinesterase (PsChe) activity was examined in adult female rat hepatocytes isolated by collagenase perfusion and maintained in a chemically defined medium supplemented with dimethyl sulfoxide. Time course studies on PsChe activity in cultured hepatocytes indicate that cells maintained in a chemically defined medium lacking human GH and 17 beta-estradiol (E2) exhibit a decrease in activity after the first 3 days in culture followed by a stabilization of PsChe activity for up to 15 days. GH (0.02, 0.2, and 2 micrograms/ml) increased PsChe activity in a dose-dependent manner. Addition of E2 (10(-5)-10(-7) M) alone to hepatocyte cultures did not cause an increase in PsChe activity. The increases produced by both the 2 micrograms/ml and 0.2 micrograms/ml GH doses plus E2 (10(-7) M) were significantly greater than controls and similar to the increase produced by GH alone. The ability of the hepatocytes to express PsChe activity was not dependent upon the continuous exposure of the cells to GH, since control cultures, maintained for 12 days in medium lacking GH, were able to express a high level of PsChe activity after the addition of GH (2 micrograms/ml) on day 12. This increase was observed in hepatocytes in culture for 30 days. These results indicate that GH plays a pivotal role in the regulation of PsChe activity in vitro, and that under the conditions used in this study, E2 does not influence the ability of hepatocytes in culture to express this enzyme.

Stimulating effects of calcium and magnesium on serum pseudocholinesterase activity.

Stimulating effects of calcium and magnesium on serum pseudocholinesterase activity.

Inhibitory effect of quinidine on plasma pseudocholinesterase activity in pregnant women

The effect of quinidine at therapeutic and subtherapeutic concentrations on pseudocholinesterase activity in the plasma of 16 normal pregnant women was studied. The mean plasma pseudocholinesterase activity in the absence of quinidine (control) was 0.67 +/- 0.11 U/ml. The mean pseudocholinesterase activity in the presence of quinidine at concentrations of 0.5, 1.0, 2.0, and 5.0 micrograms/ml 0.48 +/- 0.09, 0.38 +/- 0.09, 0.29 +/- 0.10, and 0.19 +/- 0.09 U/ml, respectively. At therapeutic concentrations needed to treat cardiac arrhythmias (2 to 5 micrograms/ml), quinidine inhibited pseudocholinesterase activity by 60% to 70%. All the plasma samples had a normal dibucaine number (78 to 85). We recommend caution when succinylcholine and/or ester-type local anesthetics are used in pregnant women receiving quinidine.

Serum pseudocholinesterase in psychiatric patients

Serum pseudocholinesterase activity was measured in 123 subjects: 16 agitated depressives, 12 retarded depressives, 7 acute schizophrenics, 14 residual schizophrenics, 16 healthy individuals, 45 surgical patients, and 13 first-degree relatives of 4 agitated depressive patients. The agitated depressive and acute schizophrenic patients had significantly higher pseudocholinesterase serum activity than their retarded inmates. As first-degree relatives of agitated depressive patients showed high levels similar to their ill relatives, a genetic component might play a crucial role. The level of pseudocholinesterase activity in serum of the surgical patients was significantly lower than that of all the psychiatric patients and the controls. The implications of this observation are still obscure.

Relationship between pseudocholinesterase and lipids in hyperlipoproteinaemia

The biological r d e of serum pseudocholinesterase (PChE) is enigmatic: the protein is normally detected and defined in terms of its catalytic hydrolysis of choline esters but no necessity for such enzymic activity in serum has ever been demonstrated. However, the now well-established association between obesity and PChE in genetic and dietary animal models (Kutty et a[., 1981, 1983), and also in clinical situations (Cucuianu et al., 1968; Chu et al., 1978), suggests that PChE may play a significant part in the aetiology of coronary heart disease (CHD), a common end-stage consequence of obesity and hyperlipoproteinaemia. Serum was collected after an overnight fast from 66 patients with confirmed C H D (80% males; age 35-60 years) and 83 matched controls. Sixteen of the C H D patients were re-investigated after treatment for 2-3 months with diet, or medication, or both, to reduce serum lipids. Cholesterol and triglycerides were measured by standard methods. Lowdensity lipoprotein (LDL) was measured by a turbidimetric method (Walton & Scott, 1964) that included both LDL and very-low-density lipoprotein (VLDL). PChE was measured with butyrylthiocholine iodide substrate (Dietz et al., 1973). Serum PChE activities in the control (mean = 3.15 pmol of thiocholine/min per ml of serum; S.D. = 0.40) did not differ significantly with age or sex in adult subjects. However, 34 C H D patients (50%) had PChE activities exceeding the control 95th percentile, and all C H D patients’ PChE activities exceeded the control mean (Fig. 1). As expected, 50% of the patients were hypercholesterolaemic and 80% were hypertriglyceridaemic by accepted clinical criteria. Correlation analysis of the combined observations from patients and controls demonstrated that PChE is positively correlated with LDL (r = 0.51) and its associated lipids, cholesterol ( r = 0.48) and triglycerides (r = 0.52). Of even greater potential significance is that 18% of the C H D patients with significantly elevated PChE had normal lipid levels. During treatment, the patients’ PChE activities dropped from 4.7 f 0.34 to 3.9 k 0.26pmol of thiocholinelmin per ml ( I = 10.1) in concert with declines in cholesterol, triglyceride and total LDL levels. Animal models (Kutty et al., 1981, 1983) suggest that excess dietary intake is a major determinant of the PChE levels. Genetically obese (oblob), diabetic (dbldb) and normal mice with gold thioglucose-induced obesity exhibit a marked increase (50-150%) in liver and serum PChE activity when diet is unrestricted. Levels of PChE are almost normal when these hyperphagic animals are maintained on restricted diets. The parallel between these experimental models and hypertrophic obesity in humans is clear. However, the problem remains of non-obese, normolipidaemic C H D patients with significantly elevated serum PChE: what is the aetiology of hyperpseudocholinesterasaemia in these individuals and is non-dietary elevated serum PChE an independent risk factor in susceptibility to atheroscleortic heart disease? How could elevated PChE levels be implicated in atherosclerosis? It is possible that the true function of PChE

Population and pharmacogenetic studies on serum cholinesterase (E): estimates of theE 1 andE 2 allele frequencies for the population of Central Italy, and of the correlation between E activity and sensitivity to succinylcholine (SCC)

392 random patients treated with SCC prior to surgery were assayed for pseudocholinesterase activity and electrophoretic pattern. The estimate of the percent frequencies of theE 1 a allele were 1.16±0.38 and of the C5 (+) phenotype 9.7±1.5, both typical of Caucasian populations. By combining the presentE 1 a gene frequency estimate with that from another sample of the same population (Cermele et al., 1987) a better estimate with smaller confidence limits was obtained, that is: 1,14±0,27. One subject interpreted asE 1 a E 1 a on phenotypic grounds was also found (expected 0,05) in this random sample. A correlation coefficient of −0.521 was found between E activity and myorelaxation time in the whole sample. High correlation values (r=−0.55 and r=−0.46) were found forE 1 u E 1 u ; C5 (−) andE 1 u E 1 u ; C5 (+) individuals, respectively, showing a strong dependence of the latter variable on the former one even within apparently homogeneous classes. The use of the product of these two variables as a classification criterion allowed the identification of a subject with very long myorelaxation time but normal activity.

Sequential changes of the autonomic nervous system in the development of cysteamine-induced duodenal ulcer, histochemical and quantitative studies.

We studied how the autonomic nervous system participated in the develop-ment of experimental duodenal ulcers due to cysteamine hydrochloride. Sym-pathetic fibers showed a slight increase in activities in the duodenal mucosa 1 h after cysteamine administration, and a marked decrease thereafter. The release of noradrenaline (NA) into the blood was suggested. Of the activities of para-sympathetic fibers, true cholinesterase activities, that are concerned with secre-tions, began to increase 1 h after cysteamine administration, which was observed most notably around the Brunner's glands in the duodenal submucosa, peaked at 8h, and then decreased or disappeared at 24h when ulcer formation was established. Pseudo cholinesterase activities that are concerned with motor func-tion, decreased over time with a resulting decrease in gastroduodenal move-ments and emptying. Meanwhile, it was confirmed by estimation of NA and cholinesterase (ChE) by means of a fluorescent histochemical study. The above findings suggest that, though the sympathetic and parasympathetic systems play their roles with a complicated interrelationship in the development of cysteamine-induced duodenal ulcers, sympathetic fibers are initially depressed, and ulcera-tion develops and advances under the parasympathetic dominance. In other words, the development of ulcers seems to depend more on the parasympathetic system than on the sympathetic system.

A peptidase activity exhibited by human serum pseudocholinesterase.

The identity of a peptidase activity with human serum pseudocholinesterase (PsChE) purified to apparent homogeneity was demonstrated by co-elution of both peptidase and PsChE activities from procainamide-Sepharose and concanavalin-A--Sepharose affinity chromatographic columns; comigration on polyacrylamide gel electrophoresis; co-elution on Sephadex G-200 gel filtration and coprecipitation at different dilutions of an antibody raised against purified PsChE. The purified enzyme showed a single protein band on gel electrophoresis under non-denaturing conditions. SDS gel electrophoresis under reducing conditions, followed by silver staining, also gave a single protein band (Mr approximately equal to 90,000). Peptidase activity using different peptides showed the release of C-terminal amino acids. Blocking the carboxy terminal by an amide or ester group did not prevent the hydrolysis of peptides. There was no evidence for release of N-terminal amino acids. Potent anionic or esterase site inhibitors of PsChE, such as eserine sulphate, neostigmine, procainamide, ethopropazine, imipramine, diisopropylfluorophosphate, tetra-isopropylpyrophosphoramide and phenyl boronic acid, did not inhibit the peptidase activity. An anionic site inhibitor (neostigmine or eserine) in combination with an esterase site inhibitor (diisopropylfluorophosphate) also did not inhibit the peptidase. However, the choline esters (acetylcholine, butyrylcholine, propionylcholine, benzoylcholine and succinylcholine) markedly inhibited the peptidase activity in parallel to PsChE. Choline alone or in combination with acetate, butyrate, propionate, benzoate or succinate did not significantly inhibit the peptidase activity. It appeared that inhibitor compounds which bind to both the anionic and esteratic sites simultaneously (like the substrate analogues choline esters) could inhibit the peptidase activity possibly through conformational changes affecting a peptidase domain.

Control proteins of complement in the sera from patients with malignant diseases

Complement hemolytic activity (CH 50) in the sera from patients with malignancies has been reported to increase with the progression of the disease. However, C_??_ inhibitor (C_??_INH) and other protease inhibitors also increase in such conditions. In this study, we examined the control proteins of the complement system, C_??_INH, C4 binding protein (C4bp), factor I (I) and factor H (H), in 254 sera from patients with various kinds of malignancies in relation to CH 50.Patients were classified according to the stage of the diseases. CH 50 was measured by the method of Mayer employing sensitized sheep erythrocytes. Protein concentrations of the complement components, C_??_INH, C4bp, I and H were determined by a single radial immuno-diffusion method. Pseudo-cholinesterase (ChE) activity was employed as a marker of protein synthesis, and patients in stage IV+V were divided into two groups according to their ChE levels.CH 50 gradually increased as the disease progressed and the elevation in stage IV+V was significant from normal subjects. Complement components C4, C3, C5, C7, C8 and C9 were correlated with CH 50. The protein concentrations of C_??_INH, C4bp, I and H also increased as the disease progressed, and all of 4 control proteins showed significant elevations in stage IV+V. There were significant correlation between CH 50 and all these control proteins.When patients in stage IV+V were subdivided according to their serum ChE levels, the patients with ChE values over 2.00I. U./l showed further elevations of CH 50, C4bp, I and H. On the other hand, patients with ChE values below 2.00I. U./l revealed significantly low CH 50, C4bp, I and H.Although CH 50 in sera of patients with malignancies increased as the disease progressed, the control proteins of the complement system also increased. It was suggested that the activation of the complement system in vivo could be interrupted by these elevated control proteins, and the state with increased levels of these control proteins seemed to be disadvantageous for the host defense against malignancy.

A simple method for the measurement of blood cholinesterase activities under field conditions

1. 1. A new separation method using a hand-driven discoidal micro-centrifuge was developed. It is suitable for separating red cells from plasma in field conditions. 2. 2. The amounts of plasma produced are sufficient to be used for the dip-stick estimation of pseudocholinesterase activity. The strip estimations of plasma pseudochoninesterase activity correlated well with the spectrophotometric method of plasma cholinesterase. The test paper methods seem to be reliable under field conditions in acute organophosphate poisonings. 3. 3. To verify the results of the paper strip methods the blood method absorbed on paper can be used. 4. 4. This method is applicable for the measuring of blood cholinesterase activities and thus monitoring humans exposed to organophosphates under field conditions.

Evaluation of the UV-340 spectrophotometric determination for pseudocholinesterase activity (EC 3.1.1.8) in human serum.

A pseudocholinesterase catalytic activity assay using p-hydroxybenzoylcholine as substrate and measuring the decrease of NADPH at 340 nm was compared with a colorimetric method using acetylthiocholine as substrate. The assay is simple, uses 50 microliters serum and is performed at 37 degrees C. Precision of the UV-340 method was good except at low ranges. The catalytic activity was depressed by the anticoagulants citrate and fluoride but not by EDTA or heparin. The reference values obtained with the evaluated UV-340 method are somewhat higher than those with the colorimetric method. As the results with both methods are comparable, the choice of procedure will depend on the local facilities.