Characteristics and behaviour of arylesterase in human serum and liver

Ameliorative Potential of Ginger (Zingiber officinale) following Repeated Coexposure with Fluoride and Dimethoate in Blood and Brain of Wistar Rats

Coexposure to exogenous neurotoxins, such as fluoride (F−) and dimethoate (DM), is a serious public health concern. In the current study, Wistar rats were exposed to DM (1/10th LD50) and F− (4.5 ppm) in drinking water individually as well as in combination continuously for 28 days and the effectiveness of ginger and quercetin was assessed in combating the oxidative stress-mediated combined toxic effects on blood and brain. Significant (p<0.05) reductions were observed in the levels of total antioxidant status (TAS), glutathione peroxidase (GPx), blood glutathione (GSH), activities of catalase (CAT), total thiols (TTH), superoxide dismutase (SOD), aryl esterase (AE), and acetylcholinesterase (AChE) whereas significant elevations (p<0.05) in malondialdehyde (MDA) and advanced oxidation protein products (AOPP) were recorded in blood and brain of coexposed rats. Administration of ginger and quercetin significantly (p<0.05) ameliorated the combined F- and DM-induced hematotoxicity as well as neurotoxicity as indicated by the levels of markers of oxidative injury in brain and blood in coexposed rats, which showed significant (p<0.05) improvement. Moreover, pathological changes, such as neurodegeneration, perivascular edema, and gliosis, observed after combined F− and DM toxicity in the brain (cerebrum and cerebellum) were markedly reduced after ginger supplementation.

Neuroprotective effect of quercetin and Zingiber officinale on sodium arsenate-induced neurotoxicity in rats

The study was aimed at determining the ameliorative potential of quercetin and Zingiber officinale (ZO) against sodium arsenate-induced neurotoxicity in male Wistar rats. Thirty adult animals were randomly allocated to five groups (n = 6). Group I served as control, groups II and IV were treated with ZO [300 mg/kg, PO (per os)/day], and group V animals were administered quercetin (50 mg/kg, PO/day) for 18 days. Groups III, IV, and V were injected with sodium arsenate (20 mg/kg, intraperitoneally/day) for 4 days starting from day 15. The administration of sodium arsenate resulted in a significant decrease in total antioxidant status, total thiols, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and aryl esterase in brain tissue of the animals compared with the control group. In addition, a significant increase was observed in malondialdehyde, advanced oxidation protein product and plasma nitric oxide levels, indicating oxidative stress-mediated neuronal damage. However, these arsenic-induced alterations were significantly reversed by quercetin or ZO in the treatment groups, indicating their ameliorative potential. These positive effects were further confirmed by histopathological examination of brain tissue revealing the suppression of severe neuronal injury, spongiosis and gliosis in the samples pretreated with quercetin and ZO. Our results suggest that inclusion of ZO and quercetin-rich foods in the diet can help in preventing the neurotoxic effects in areas with elevated levels of arsenic in food chain and ground water.

Protective Effect of Quercetin and Ginger (Zingiber officinale) Extract against Dimethoate Potentiated Fluoride-Induced Nephrotoxicity in Rats

This study aimed to determine the potential of quercetin and Zingiber officinale (ZO) Roscoe extract to alleviate the renal damage induced by dimethoate (DM) and fluoride (F^-) alone and by their combined exposure in rats. A total of 54 adult Wistar rats were randomly allocated to nine groups (n = 6). A sub-lethal dose of DM (1/10th of the median lethal dose) was administered by oral gavage alone and along with F^- (4.5 ppm, three-fold the permissible limit) in their drinking water continuously for 28 days. Chromatographical analysis revealed the presence of quercetin, curcumin, and other phytochemicals with strong antioxidant properties in ZO-rhizome extract. Severe changes were observed in the levels of the renal biomarkers and histoarchitecture after co-administration of the toxicants, indicating greater kidney damage. The administration of ZO extract (300 mg/kg) along with either or both toxicants led to a significant restoration of the biochemical markers and renal antioxidant profile and histology.

Impact of Chronic Sodium Fluoride Toxicity on Antioxidant Capacity, Biochemical Parameters, and Histomorphology in Cardiac, Hepatic, and Renal Tissues of Wistar Rats

The study was designed to determine the fluoride distribution after its oral exposure in drinking water and its associated impact on biochemical, antioxidant markers and histology in the liver, kidney, and heart of male Wistar rats. On 100 ppm exposure, the highest accretion of fluoride occurred in the liver followed by the kidney and heart. Fluoride exposure significantly (p˂0.05) increased the plasma levels of dehydrogenase, aminotransferases, kidney injury molecule-1 (KIM-1), and other plasma renal biomarkers but decreased the levels of total plasma proteins and albumin in a dose-dependent manner. Reduction (p˂0.05) in the activities of antioxidant enzymes viz. acetylcholinesterase, arylesterase, superoxide dismutase, catalase, glutathione peroxidase, and reductase with increased levels of protein and lipid peroxidation was recorded in the liver, kidney, and heart of fluoride-administered rats. Fluoride exposure (100 ppm) induced lipid peroxidation was highest in kidney (4.4 times) followed by liver (2.6 times) and heart (2.5 times) and as compared to their respective control. The percent rise in protein oxidation at 30% was almost equal in the kidney and liver but was 21.5% in the heart as compared to control. The histopathological alterations observed included congestion and hemorrhage along with degeneration and necrosis of parenchymal cells in hepato-renal tissues and myocardium, severity of which varied in a dose-dependent manner. Taken together, fluoride distribution in the liver, heart, and kidney after chronic fluoride intake correlated well with fluoride-induced hepatic and cardio-renal toxicity in a concentration-dependent manner. These results draw attention that chronic fluoride intake pose a significant health risk for human and animal residents of fluoride endemic areas.

Neuroprotective potential of hydroethanolic hull extract of Juglans regia L. on isoprenaline induced oxidative damage in brain of Wistar rats

The study was aimed at assessing isoprenaline (ISO) induced oxidative damage in brain of Wistar rats and its protection by hydroethanolic hull extract of Juglans regia. Administration of ISO significantly increases catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), malondialdehyde (MDA) and advanced oxidation protein product (AOPP) levels and significantly reduced activities of antioxidant status (TAS), total thiols (TTH), acetylcholinesterase (AChE), arylesterase (AE), and glutathione peroxidase (GPx) in rat brain. Histopathologically, neuronal degeneration, spongiosis and gliosis were seen in cerebral cortex after ISO administration. Pretreatment with hull extract restored TAS, TTH, AChE, CAT and SOD values. Additionally, significant reductions were noted in levels of MDA, AOPP, and severity of histomorphological changes in cerebral cortex following hull extract treatment. Altered antioxidant biomarkers along with histopathological changes indicate oxidative injury in rat brain following ISO administration. Repeated administration of J. regia hull extract demonstrating presence of neuroprotective properties against ISO induced oxidative damage in rat brain.

Oxidative stress during early pregnancy and birth outcomes

Objective

Routine high-dose Fe supplementation in non-anaemic pregnant women may induce oxidative stress and eventually affect birth outcomes. The aim of the present study was to measure oxidative stress markers in pregnant women with low/normal and high Hb values in trimester 1 (Hb1) and to relate these to birth weight.

Design

A cross-sectional study where selected oxidative stress markers were analysed in both maternal (trimester 1; T1) and cord blood samples and correlated with birth weight.

Setting

A tertiary hospital in urban South India.

Subjects

One hundred women were chosen based on their Hb1 values (forty women with low/normal Hb1 (<110 g/l) and sixty women with high Hb1 (≥120 g/l)).

Results

In T1, women with high Hb1 values were found to have lower paraoxonase-1 (PON-1) activity (424·7 (sd 163·7) v. 532·9 (sd 144·7) pmol p-nitrophenol formed/min per ml plasma, P=0·002) and higher lipid peroxides compared with women with low/normal Hb1. Routine supplementation of Fe to these women resulted in persistent lower PON-1 activity in cord blood (P=0·02) and directionally lower (P=0·142) birth weights. Furthermore, women with high Hb1 who delivered low-birth-weight babies were observed to have lowest PON-1 activity in T1. No changes were observed in other markers (myeloperoxidase activity and total antioxidant levels).

Conclusions

Routine Fe supplementation in pregnant women with high Hb1 associated with increased oxidative stress, as reflected by low PON-1 activity in T1, could potentially lead to deleterious effects on birth weight.

Paraoxonases and chemokine (C-C motif) ligand-2 in noncommunicable diseases

Oxidative stress and inflammation underpin most diseases; their mechanisms are inextricably linked. Chronic inflammation is associated with oxidation, anti-inflammatory cascades are linked to decreased oxidation, increased oxidative stress triggers inflammation, and redox balance inhibits the inflammatory cellular response. Whether or not oxidative stress and inflammation represent the cause or consequence of cellular pathology, they contribute significantly to the pathogenesis of noncommunicable diseases (NCD). The incidence of obesity and other related metabolic disturbances are increasing, as are age-related diseases due to a progressively aging population. Relationships between oxidative stress, inflammatory signaling, and metabolism are, in the broad sense of energy transformation, being increasingly recognized as part of the problem in NCD. In this chapter, we summarize the pathologic consequences of an imbalance between circulating and cellular paraoxonases, the system for scavenging excessive reactive oxygen species and circulating chemokines. They act as inducers of migration and infiltration of immune cells in target tissues as well as in the pathogenesis of disease that perturbs normal metabolic function. This disruption involves pathways controlling lipid and glucose homeostasis as well as metabolically driven chronic inflammatory states that encompass several response pathways. Dysfunction in the endoplasmic reticulum and/or mitochondria represents an important feature of chronic disease linked to oxidation and inflammation seen as self-reinforcing in NCD. Therefore, correct management requires a thorough understanding of these relationships and precise interpretation of laboratory test results.

The effect of age on the paraoxonase and arylesterase activity of pregnant mothers and their infants

AIM

The study aimed to research the effect of maternal age at pregnancy on the paraoxonase (PON) and arylesterase activity levels of mothers and infants.

METHOD

The study comprised 30 mothers aged more than 35 years and their infants, and 30 mothers aged under 25 years and their infants. All pregnancies had been of 38-42 weeks with normal spontaneous vaginal birth. PON and arylesterase activities were measured using paraoxon and phenylacetate substrates.

RESULTS

When the PON and arylesterase enzyme activities were compared, the PON and arylesterase activity of the mothers aged more than 35 years was found to be statistically significantly lower compared to that of the mothers aged under 25 years (P = 0.006 and P = 0.03, respectively), while there was no statistically significant difference in PON and arylesterase enzyme activity between the two groups of infants (P > 0.05).

CONCLUSION

While the PON and arylesterase enzyme activity of the mothers aged more than 35 years was found to be significantly lower compared to that of the mothers aged under 25 years, there was no statistical significance between the infants. This can be explained by the reduced PON and arylesterase enzyme activity during pregnancies at an older age, although this did not affect the PON and arylesterase enzyme activity of the infants.

Interrelationships between paraoxonase-1 and monocyte chemoattractant protein-1 in the regulation of hepatic inflammation

Oxidative stress and inflammation play a central role in the onset and development of liver diseases irrespective of the agent causing the hepatic impairment. The monocyte chemoattractant protein-1 is intimately involved in the inflammatory reaction and is directly correlated with the degree of hepatic inflammation in patients with chronic liver disease. Recent studies showed that hepatic paraoxonase-1 may counteract the production of the monocyte chemoattractant protein-1, thus playing an anti-inflammatory role. The current review summarises experiments suggesting how paraoxonase-1 activity and expression are altered in liver diseases, and their relationships with the monocyte chemoattractant protein-1 and inflammation.

Ghrelin, Nitrite and Paraoxonase/Arylesterase Concentrations in Cement Plant Workers

Occupational cement dust exposure has been associated with an increased risk of liver abnormalities, pulmonary disorders, and carcinogenesis. Decreased antioxidant capacity and increased plasma lipid peroxidation have been posed as possible causal mechanisms of disease. Accordingly, this study examined the serum paraoxonase (PON1) arylesterase (AE), ghrelin, HDL-C, LDL-C and serum nitrite (NOx) levels in cement dust exposed workers. Twenty-eight volunteer male cement plant workers and 30 volunteer control male workers, aged 29-54 years, participated. The concentrations of serum PON1, AE, NOx, ghrelin, and HDL-cholesterol and LDL-cholesterol were measured in both groups. PON-1, AE, ghrelin and HDL-cholesterol were lower in the cement plant workers than in controls. Serum nitrite (NOx), and LDL-C levels in cement plant workers were higher (p<0.05) than in the control group workers. No correlation was observed between the serum levels of HDL-cholesterol and PON1 and between HDL-cholesterol and ghrelin. A weak negative correlation was detected between the serum ghrelin and NOx. The study results strongly suggest that HDL-paraoxonase, AE, ghrelin, HDL-C, and high NOx, and LDL-C levels may have a role in disease involving oxidative damage. However, some studies are necessary to address the association between occupational dust exposure and respiratory symptoms.

Serum paraoxonase 1 activity status in patients with liver disorders

BACKGROUND/AIM

Paraoxonase 1 (PON1) is an esterase, exclusively synthesized by liver. The present study has two objectives: to determine the PON1 activity status in various disorders associated with hepatocellular damage and to correlate the changes of PON1 activity with the standard liver function and fasting lipid profile tests in these disorders.

PATIENTS AND METHODS

The study groups consisted of 95 patients with liver diseases including acute viral hepatitis (14), cirrhosis with portal hypertension (33), leptospirosis (14), sepsis and multi organ failure (15), left ventricular failure (9), and falciparum malaria (10); and 53 healthy controls. Serum PON1 activity was measured manually using spectrophotometer. Liver function test parameters and fasting lipid profile were performed in clinical chemistry auto analyzer (Hitachi 912).

RESULTS

The serum PON1 activity in patients with acute viral hepatitis and sepsis decreased significantly ( P < 0.001) and moderately in falciparum malaria ( P < 0.05). However, in patients with cirrhosis, leptospirosis and left ventricular patients, its activity did not change significantly. On applying Pearson correlation, serum PON1 activity correlated positively with high-density lipoprotein-cholesterol (HDL-C) in patients with sepsis (r=0.633, P < 0.05), left ventricular failure patients (r=0.814, P < 0.05) and negatively with acute viral hepatitis patients (r=-0.528, P <0.05).

CONCLUSION

PON1 activity has decreased significantly in acute viral hepatitis, sepsis with multi organ failure and falciparum malaria patients. Determination of PON1 activity may serve as a useful additional test in assessing these conditions.

Measurement of serum paraoxonase-1 activity in the evaluation of liver function

Paraoxonase-1 (PON1) is an esterase and lactonase synthesized by the liver and found in the circulation associated with high-density lipoproteins. The physiological function of PON1 seems to be to degrade specific oxidized cholesteryl esters and oxidized phospholipids in lipoproteins and cell membranes. PON1 is, therefore, an antioxidant enzyme. Alterations in circulating PON1 levels have been reported in a variety of diseases involving oxidative stress including chronic liver diseases. Measurement of serum PON1 activity has been proposed as a potential test for the evaluation of liver function. However, this measurement is still restricted to research and has not been extensively applied in routine clinical chemistry laboratories. The reason for this restriction is due to the problem that the substrate commonly used for PON1 measurement, paraoxon, is toxic and unstable. The recent development of new assays with non-toxic substrates makes this proposal closer to a practical development. The present editorial summarizes PON1 biochemistry and function, its involvement with chronic liver impairment, and some aspects related to the measurement of PON1 activity in circulation.

Schistosoma mansoni: effect of dietary zinc supplement on egg granuloma in Swiss mice treated with praziqantel

Schistosomiasis is one of the most important parasitic diseases in Egypt and chemotherapy is considered the most effective method of control. This study was conducted to assess the effectiveness of zinc administration against Schistosoma mansoni infection by evaluating the activities of arylesterase and paraoxonase (PON1) enzymes, and the degree of liver damage. One hundred and twenty albino mice were divided into two groups; one was an infected control and the other a treated group which was further subdivided into three according to the praziquantel and zinc supplementation given. Blood and liver samples, collected 10 weeks post-infection, were subjected to parasitological, histopathological, and enzyme assays, and immunological studies. The results showed that dietary zinc supplementation led to marked reduction in worm load, and egg deposition in the liver and intestine. Histopathological examination showed marked reduction in the number and diameter of hepatic granulomas in the treated groups. The activity of arylesterase and PON1 enzymes were partially restored in infected animals receiving zinc. IL-10 mRNA expression was higher in the treated groups than in the infection control group. In conclusion, zinc administration could be a promising adjuvant therapy for S. mansoni infection.

The paraoxonases: role in human diseases and methodological difficulties in measurement

Research into the paraoxonase (PON) gene family has flourished over the past few years. In the 1970s and 1980s, only PON1 was known, and the investigations were conducted, essentially, by toxicologists focusing on protection against organophosphate poisoning. Since then, two new members of the family, PON2 and PON3, have been identified, both being shown to play antioxidant and anti-inflammatory roles. Evidence exists indicating that the PON family is central to a wide variety of human illnesses such as cardiovascular disease, diabetes mellitus, metabolic syndrome, obesity, non-alcoholic steatohepatitis, and several mental disorders. However, research is hampered considerably by the methods currently available to measure the activity of these enzymes. In this review, we summarize the state of knowledge on PON biochemistry and function, the influence of genetic variations, and the involvement of PON in several diseases. The problems associated with PON measurement, such as sample acquisition, lack of reference methods, and variety of substrates, will be presented. Also, we cover some of the present lines of research and propose some others for future progress in this field.

Maternal chronic hepatitis B virus is implicated with low neonatal paraoxonase/arylesterase activities

BACKGROUND

Paraoxonase/arylesterase activities are closely implicated with liver function and antiatherogenetic process.

AIM

To evaluate whether maternal chronic hepatitis B virus, disease (HBV) affect serum neonatal paraoxonase/arylesterase activities.

PATIENTS AND METHODS

28 pregnant women with HBV and 28 healthy pregnant women (controls) in the delivery room and their newborns (cord blood) underwent laboratory examinations. Serological virus tests and liver function tests and paraoxonase (PON 1) activities were measured with the Siemens Advia 1650 Clinical Chemistry System, while total antioxidant capacity (TAC) levels and paraoxonase-arylesterase (PON-aryl) activities were measured spectrophotometrically.

RESULTS

Serological HBV tests and HBV DNA showed chronic HBV (precore mutant G1896A) in the diseased mothers whereas anti-HBc and anti-HBe were detected in their neonates. Liver function parameters were found normal in controls and both groups of newborns. Moderately increased transaminase levels were measured in HBV mothers, whereas TAC levels were decreased in hepatic mothers and their newborns. Interestingly albumin levels did not differ among the studied groups. PON 1 and PON-aryl activities in the diseased mothers (148+/-14 U/mL/min, 130+/-16 KU/mL/min) and their infants (32+/-6 U/mL/min, 24+/-5 KU/mL/min) were significantly lower as compared to those of control mothers (217+/-16 U/mL/min, 196+/-14 KU/mL/min p<0.001) and their newborns (57+/-6 U/mL/min, 48+/-8 UK mL/min p<0.001). Inverse significant correlations were found between the studied enzyme activities and liver enzymes in all the groups of study except in infants born from HBV mothers and positive with TAC in all the studied groups.

CONCLUSIONS

Decreased PON 1 and PON-aryl activities were measured in infants born from hepatic mothers probably as a consequence of their low TAC. Infants born from HBV mothers are at risk for developing LDL oxidation perinatally.

PON1 status of farmworker mothers and children as a predictor of organophosphate sensitivity

The objective was to determine PON1 status as a predictor for organophosphorus insecticide sensitivity in a cohort of Latina mothers and newborns from the Salinas Valley, California, an area with high levels of organophosphorus insecticide use. PON1 status was established for 130 pregnant Latina women and their newborns using a high-throughput two substrate activity/analysis method which plots rates of diazoxon (DZO) hydrolysis against rates of paraoxon (PO) hydrolysis. Arylesterase activity (AREase) was determined using phenylacetate as a substrate, allowing comparison of PON1 levels across PON1192 genotypes in mothers and children. Phenylacetate hydrolysis is not affected by the Q192R polymorphism. Among newborns, levels of PON1 (AREase) varied by 26-fold (4.3-110.7 U/ml) and among mothers by 14-fold (19.8-281.4 U/ml). On average, children's PON1 levels were four-fold lower than the mothers' PON1 levels (P<0.001). Average PON1 levels in newborns were comparable with reported hPON1 levels in transgenic mice expressing human PON1Q192 or PON1R192, allowing for prediction of relative sensitivity to chlorpyrifos oxon (CPO) and DZO. The predicted range of variability in sensitivity of mothers and children in the same Latino cohort was 65-fold for DZO and 131 to 164-fold for CPO. Overall, these findings indicate that many of the newborns and some of the mothers in this cohort would be more susceptible to the adverse effects of specific organophosphorus pesticide exposure due to their PON1 status. Of particular concern are exposures of pregnant mothers and newborns with low PON1 status.

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 (20%), triglyceride from 133+/-51.2 to 86+/-34.0 (35%), 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.

Serum Paraoxonase Activity: A New Additional Test for the Improved Evaluation of Chronic Liver Damage

Background: Paraoxonase 1 (PON1) is an ester hydrolase present in serum and in the liver. The aims of the present study were to investigate the following: (a) the relationship between serum PON1 activity alterations and the degree of liver damage in patients with chronic liver disease; (b) the influence of genetic variability on serum PON1 activity; and (c) the efficacy of serum PON1 activity measurement, alone and in combination with standard liver function tests, in the assessment of liver damage.

Methods: We studied 68 patients with liver cirrhosis, 107 patients with chronic hepatitis, and 368 apparently healthy volunteers. Baseline and salt-stimulated PON1 activities were measured by the hydrolysis of paraoxon. PON1 genotyping at positions 55 and 192 was analyzed by PCR and restriction isotyping.

Results: Baseline and stimulated PON1 activities were decreased (P &lt;0.001) in chronic hepatitis and in liver cirrhosis. PON1 activity was significantly correlated with serum total proteins, albumin, and bilirubin in patients but not in controls. There were no significant differences with respect to allele and genotype frequencies between patients and controls. The combination of baseline serum PON1 with five standard biochemical tests had a higher classification accuracy (94% of patients; 96% of controls) than the five standard tests alone (75% of patients; 96% of controls). ROC plots demonstrated a high diagnostic accuracy for baseline serum PON1 [area under the curve, 0.89 (95% confidence interval, 0.86–0.93) in chronic hepatitis and 0.96 (95% confidence interval, 0.94–0.99) in cirrhosis]. Baseline PON1 provided the highest ROC area for cirrhosis vs controls.

Conclusions: The significant decrease of PON1 activity in chronic liver diseases is related to the degree of hepatic dysfunction and not to allelic or genotypic differences. Addition of serum PON1 activity measurement to the current battery of tests may improve the evaluation of chronic liver diseases.

ELISA using monoclonal antibody to human serum arylesterase

ELISA for determining arylesterase content in human serum has been developed by the one-step sandwich method using 2 monoclonal antibodies. While the content of arylesterase in healthy adults was 81 +/- 25 mg/l, a decrease was observed in patients with liver cirrhosis, where the mean +/- SD was 37 +/- 7 mg/l. ELISA of human serum arylesterase correlated with the activity determined by a specific substrate assay we devised recently.

Cholinesterase, arylesterase, and lipoprotein parameters in twins

A high heritability estimate was obtained for serum arylesterase activity level in a series of 40 male twin pairs (23 MZ, 17 DZ) aged 33-39 years. The heritability estimated for cholinesterase activity was strikingly lower. In unrelated individuals a positive correlation between arylesterase, cholinesterase, and various lipoprotein parameters appeared to support the suggestion that these enzymes interact with various lipoproteins at the molecular level. The nature of these associations is not known. It is, however, tempting to speculate that some of the hereditary influence on lipoprotein levels in man may be mediated through the genetic control of one or both of these enzymes.