Serum arylesterase and paraoxonase activity in patients with chronic hepatitis

AIM： To investigate the relationship between serum paraoxonase （PON1）, AST, ALT, GGT, and arylesterase （AE） activity alterations and the degree of liver damage in patients with chronic hepatitis. METHODS： We studied 34 chronic hepatitis patients and 32 control subjects, aged between 35 and 65 years, in the Department of Infection and Clinical Microbiology at the Firat University School of Medicine. Blood samples were collected from subjects between 8：00 and 10：00 a.m. following a 12-h fast. Baseline and salt-stimulated PON1 activities were measured by the hydrolysis of paraoxon. Phenyl acetate was used as the substrate and formed phenol was measured spectrophotometrically at 270 nm after the addition of a 10-fold diluted serum sample in AE activity measurements. RESULTS： The results of this investigation revealed that the levels of AE activity decreased from 132±52 to 94± 36 （29%）, baseline PON1 activity from 452±112 to 164 ±67 （64%）, salt-stimulated PON1 activity from 746± 394 to 294±220 （61%）, HDL from 58.4±5.1 to 47.2±5.6 （200）, triglyceride from 133±51.2 to 86±34.0 （350）, while a slight increase in the level of LDL （from 163± 54.1 to 177.3±56.0; 9%） and significant increases in the levels of AST （from 29±9.3 to 98±44）, ALP （from 57.2±13.1 to 91±38.1）, ALT （from 27.9±3.32 to 89± 19.1）, GGT （from 24.3±2.10 to 94±48.2）, total bilirubin （from 0.74±0.02 to 1.36±0.06; 84%） and direct bilirubin （from 0.18±0.01 to 0.42±0.04; 133%） were detected. However, the levels of albumin, total protein, cholesterol, and uric acid were almost the same in chronic hepatitis and the control subjects.CONCLUSION： Low PON1 and AE activity may contribute to the increased liver dysfunction in chronic hepatitis patients by reducing the ability of HDL to retard LDL oxidation and might be clinically useful for monitoring the disease of chronic hepatitis.

Fast estimation of Michaelis-Menten constant of arylesterase with a pair of medium concentrations of substrate

Objective: To investigate the reliability for fast estimation of Michaelis-Menten constant (Km) with calibrated specific activity at only two medium concentrations of substrate by both simulation and experimentation with arylesterase (ArE)as model. Methods: Initial rates were simulated by randomly inserting uniform absolute error, and the experimental initial rates of ArE were determined by measuring the increaser of product absorbance. Calibrated specific activities at two substrate concentrations were obtained by regression analysis, and Km was calculated according to Michaelis-Menten equation. Results: By simulation with calibrated specific activities at two medium substrate concentrations, Km could be calculated according to Michaelis-Menten equation with reasonable precision and accuracy. By experimentation with substrates of 2-naphthyl acetate, phenyl acetate, and p-nitrophenyl acetate, there were no differences between the mean and SD of Km of ArE for either substrate by this linear kinetic method and the Lineweaver-Burk plot. Conclusion: This linear kinetic method was reliable for fast estimation of the Km of some specified enzyme on its substrate of lower solubility or lower sensitivity for quantification by common methods.

Total oxidative stress, paraoxonase and arylesterase levels at patients with pseudoexfoliation syndrome and pseudoexfoliative glaucoma

AIMTo investigate the oxidative stress status of the aqueous humor and serum of patients with pseudoexfoliation (PEX) syndrome and pseudoexfoliative glaucoma (PEG) and to measure paraoxonase (PON) and arylesterase (ARE) levels.METHODSA total of 78 patients were enrolled in the study, with 26 patients in each separate group. The patients were divided into three groups: the first group entailed PEX syndrome patients, while the second group consisted of patients with PEG and the third group involved patients with no additional systemic diseases, other than the diagnosis of cataract as control. Total oxidative stress (TOS), total antioxidant capacity (TAC), PON, and ARE levels in aqueous humor and serum were measured.RESULTSTAC, PON and arylesterase levels in aqueous humor and serum of the PEX syndrome and PEG patients were significantly decreased compared with control group (P<0.05). TOS values were higher in patients with PEX syndrome and PEG than controls (P<0.05). TAC, PON and ARE levels of aqueous humor did not differ significantly between the PEX syndrome and PEG groupsCONCLUSIONThese findings are potentially of significance and add to the growing body of evidence for oxidative stress in PEX syndrome and PEG. Decreased antioxidant defense and increased oxidative stress system may play an important role in the pathogenesis of PEX syndrome and PEG.

Correlation of serum arylesterase activity on phenylacetate estimated by the integrated method to common classical biochemical indexes of liver damage

The correlation of serum arylesterase(PON1) activity on phenylacetate determined by an integrated method to clas-sical biochemical indexes of liver damage was investigated for the use of PON1 activity to evaluate liver damage.PON1 reaction curve as absorbance at 270 nm for 0.20 mmol/L phenylacetate hydrolysis was analyzed by the integrated method to determine maximal PON1 reaction rate.Classical biochemical indexes of liver damage were determined routinely.The 95% confidence threshold of PON1 activity in sera from healthy individuals was 2.12 mkat/L [(4.73±1.31) mkat/L,n=105].PON1 activity in clinical sera was closely correlated to serum albumin,total protein and the ratio of albumin to globulins,but was weakly correlated to both direct and total bilirubin in serum.There were no correlations of PON1 activity to γ-glutamyltransferase,alkaline phos-phatase,alanine aminotransferase and aspartate aminotransferase.Among 127 clinical sera with PON1 activity>2.12 mkat/L,there were 92% healthy individuals examined by albumin,90% healthy individuals examined by total protein,88% healthy individuals examined by total bilirubin,86% healthy individuals examined by direct bilirubin and 64% healthy individuals examined by the ratio of albumin to globulins,respectively.In each group of healthy individuals judged by classical biochemical indexes of close correlation to PON1 activity,percentage of healthy individuals examined by PON1 activity was always >80%.These results suggested PON1 activity on phenylacetate estimated by the integrated method was also suitable for the evaluation of liver damage.

Anti-ulcer Activity of Curcumin on Experimental Gastric Ulcer in Rats and Its Effect on Oxidative Stress/Antioxidant,IL-6 and Enzyme Activities

Objective To investigate the possible mechanism by which curcumio protects stomach during the acute chronic phase of gastric ulcer disease. Methods The rats were divided into four groups and fasted for 2 days with flee access to water. On the third day, the animals were fasted for a further 24 h with no access to water followed by surgery. Rats received different doses of curcumin （20, 40, and 80 mg/kg） or vehicle by oral gavage. Nineteen hours after ulcer induction, the rats were killed by decapitation. Stomach was opened along the greater curvature and ulcerative lesions were counted. Total juice acidity, neutrophils activity, mitochondrial activity, total antioxidants, paraoxonase （PON 1）/arylesterase and total peroxides were evaluated. DNA fragmentation （%） and pro-inflammatory cytokine IL-6 level were measured. The level of different gastro-cytoprotective effectors including total antioxidants and paraoxonase （PON 1）/arylesterase activities was measured. Results The anti-ulcer activity of curcumin was displayed by attenuating the different ulcerative effectors including gastric acid hyper-secretion, total peroxides, myeloperoxiase （MPO） activity, IL-6 and apoptotic incidence. Conclusion Cureumin appears to have a propitious protective effect against gastric ulcer development.

An assessment of antioxidant status in patients with carbon monoxide poisoning

BACKGROUND: Carbon monoxide poisoning(COP) is an important cause of mortality and morbidity worldwide. This study was to investigate the levels of serum paraoxonase(PON), arylesterase(ARYL), ceruloplasmin(Cp), and sulfhydryl(-SH) in the treatment of COP, and to further understand the pathophysiology of COP.METHODS: This prospective study comprised 107 individuals with COP(group 1) and 50 healthy volunteers(group 2). Serum, plasma, and erythrocyte samples were taken on admission from all participants with COP. This process was repeated in the 90 th and 180 th minutes of treatment. Samples were taken from the control group only once. The levels of plasma PON, ARYL, Cp activity and-SH were measured in both groups.RESULTS: Age, gender, and carboxyhemoglobin level were not correlated with PON, ARYL, Cp, and-SH levels. PON, ARYL, and-SH levels were signifi cantly decreased in group 1 compared with group 2. Conversely, Cp was signifi cantly elevated in group 1 in contrast to group 2. Although ARYL was lower on admission in patients with COP than that was observed in the 90 th and 180 th minutes(P<0.001), Cp was higher on admission than at the other time points(P<0.001).CONCLUSIONS: Participants with COP had decreased levels of antioxidants(PON, ARLY, and-SH). COP represses the antioxidant system.

Effects of aerobic training on serum paraoxonase activity and its relationship with PON1-192 phenotypes in women

Background：Paraoxonase 1（PON1） is an antioxidant enzyme that protects high-density lipoprotein（HDL） and low-density lipoprotein against oxidation.Limited studies have addressed the influenc of exercise on PON1 activity and its relationship with PON1 phenotypes.We investigated relationships between PON1-192 phenotypes,PON1 activity,aerobic exercise,and blood lipid and lipoprotein concentrations in middle-aged women.Methods：An exercise group（n=50） engaging in regular aerobic exercise and a control group（n=41） were selected from a subset of 300 Caucasian women that met the inclusion criteria.Serum PON1,salt-stimulated PON1（SSPON1）,and arylesterase（ARE） activities;cholesterol levels and ARE activities of total HDL and HDL subgroups（HDLs）（supernatants obtained by polyethylene glycol）;and blood lipid and lipoprotein concentrations were determined by standardized enzymatic methods.PON1-192 QQ（low activity）,QR（moderate activity）,and RR（high activity） phenotype groups were define using serum SSPON1/ARE activity ratios.The R-carries（RC） phenotype group consisted of the QR and RR groups combined.Results：All lipid and lipoprotein concentrations were greater in the exercise group than in the control group.Regardless of phenotype,no significan differences were observed between the exercise and control groups in terms of serum PON1,SSPON1,or ARE activity associated with HDLs（p〉 0.05）,whereas PON1 activities in QQ-phenotyped women in the exercise group were significant y higher than those in the control group（p〈0.01）,but not the RC group.A statistically significan interaction between PON1 phenotypes（QQ and RC groups） and exercise（exercise and control groups） on PON1 activity was found.Conclusion：These results showed that a regular aerobic exercise program can improve PON1 activity depending on PON1-192 phenotype,but not on lipid and lipoprotein levels,in middle-aged Turkish women.