Blood Butyrylcholinesterase Research Articles

Association of Reduced Maternal Plasma Cholinesterase Activity With Preeclampsia: A Meta-Analysis.

Blood butyrylcholinesterase (BChE) activity has been found to decrease during pregnancy and reportedly decrease even more in preeclampsia (PE). The purpose of the present meta-analysis was to answer a specific question of whether BChE activity (in the plasma, serum, or whole blood) is reduced in pregnant women suffering from PE compared to those with normal pregnancy. The meta-analysis included 15 studies with 20 records of BChE activity in 608 women compared to 569 healthy pregnant (control) ones. The studies were subjected to quality assessment using the Newcastle-Ottawa Scale (NOS). Using the Meta-Essentials software program 1.5, the one-group random effects model and forest plot revealed that the percentage of BChE activity in pregnant women with PE was 84.84% of the control value, with a standard error of 4.09 and 95% C.I. of 76.28, 93.41, indicating a significant 15.16% reduction in BChE activity in comparison to healthy pregnancy. No significant heterogeneity was seen in the analyzed data and the funnel plot did show publication bias. Subgroup (mild, severe, and unclassified PE) forest plot analysis revealed that the % BChE activities in PE compared to respective healthy pregnancies were 96.28%, 97.08%, and 76.62%, respectively with no heterogeneity. The median NOS score of the 15 studies included in the meta-analysis was 7, ranging from 5 to 8 (medium to high quality), and the forest plot showed an effect size of 0.735. This meta-analysis shows that BChE activity is reduced in PE compared with normal pregnancyand its value as a biomarker warrants further clinical studies.

Decreased Activity of Circulating Butyrylcholinesterase in Blood Is an Independent Prognostic Marker in Pancreatic Cancer Patients.

Introduction: The activity of butyrylcholinesterase (BChE) in blood reflects liver function and has recently been associated with systemic inflammatory response and tumor cachexia. As these conditions have been previously linked with pancreatic cancer (PC), the purpose of the present study was to evaluate the prognostic impact of plasma BChE in PC. Methods: Data from 574 consecutive PC patients, treated between 2004 and 2018 at a single academic center, was evaluated. The primary endpoint was cancer-specific survival (CSS), analyzed by Kaplan–Meier curve, and both univariate and multivariate Cox proportional models. Results: BChE activity negatively correlated with other liver parameters (bilirubin, gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and C-reactive protein (CRP)), and positively correlated with albumin levels, respectively (p < 0.01). In univariate analysis, a low plasma BChE activity was a factor of poor CSS (hazard ratio: 1.4, 95% confidence interval: 1.129–1.754, p = 0.002). In multivariate analysis, tumor stage, tumor grade, administration of chemotherapy, bilirubin levels and a low BChE activity (hazard ratio: 1.42, 95% confidence interval: 1.10–1.82; p = 0.006) were identified as independent prognostic factors. Conclusion: Decreased activity of BChE in blood plasma predicts shorter survival time in PC patients. Therefore, BChE might be helpful in additional stratification of patients into different prognostic risk groups.

Ex-vivo Acetylcholinesterase and Butyrylcholinesterase Inhibitory Activities Assay of G. asiatica and G. tiliaefolia (Tiliaceae) Leaves

Aims: Our study was carried out to appraise acetylcholinestrase (AChE) and butyrylcholinestrase (BChE) inhibitory activities of Grewia asiatica and Grewia tiliaefolia leaves extracts.&#x0D; Study Design: For the purpose of these experiments the extracts were subjected to an ex-vivo study.&#x0D; Place and Duration of Study: The study was carried out between June 2018 to December 2018 in the Department of Pharmacy, Southeast University, Dhaka, Bangladesh.&#x0D; Methodology: In this study, cholinesterase inhibitory activities of different fractions of crude ethanol extract of both plants were examined using swiss albino mice at 300 mg/kg b.w. dose. We determined anti-acetylcholinestrase (AChE) and anti-butyrylcholinestrase (BChE) activities using slightly modified Elman coupled enzyme assay.&#x0D; Results: The highest inhibition of bovine brain acetylcholinesterase and human blood butyrylcholinesterase were exhibited by PEF and CLF of G. asiatica with the IC50 values were found to be 55.88 μg/ml and 26.14 μg/ml respectively whereas the highest inhibition of bovine brain acetylcholinesterase and human blood butyrylcholinesterase were exhibited by CLF of G. tiliaefolia. &#x0D; Conclusion: The result of the present study on various fractions of these plants has a considerable anti-acetylcholinesterase and anti-butyrylcholinesterase activities which suggest its effectiveness against various neurodegenerative disorders.

Butyrylcholinesterase-a potential plasma biomarker in manganese-induced neurobehavioral changes.

Groundwater particularly drinking water contamination with metals has created an environmental disaster in Bangladesh. Manganese (Mn), an essential trace element, plays a key role in the development and function of the brain. Excess Mn exposure is reported to be associated with complex neurological disorders. Here, we have found a notably large extent of Mn above the permissive limit in the tube-well water of Rajshahi and Naogaon districts in Bangladesh. Higher levels of Mn in hair and nail samples, and a decreasing level of butyrylcholinesterase (BChE) activity were detected in plasma samples of the human subjects recruited from Naogaon district. Mn concentrations in water, hair, and nails were negatively correlated with the plasma BChE levels in Mn-exposed populations. To compare and validate these human studies, an animal model was used to determine the in vivo effects of Mn on neurobehavioral changes and blood BChE levels. In elevated plus maze, the time spent was significantly reduced in open arms and increased in closed arms of Mn-exposed mice compared to control group. The mean latency time to find the platform was declined significantly in control mice compared to Mn-treated group during 7days in Morris water maze test, and Mn-exposed group also spent significantly less time in the desired quadrant as compared to the control group in probe trial. BChE activity was significantly reduced in Mn-exposed mice compared to control mice. Taken together, these results suggest that plasma BChE levels may serve as reliable biomarker of Mn-induced neurotoxicity related to behavioral changes.

Erratum: “A Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based Endpoint for Chlorpyrifos”

Vol. 126, No. 9 ErratumOpen AccessErratum: “A Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based Endpoint for Chlorpyrifos”is correction ofA Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based End Point for Chlorpyrifos Todd J. Zurlinden and Brad Reisfeld Todd J. Zurlinden Search for more papers by this author and Brad Reisfeld Search for more papers by this author Published:6 September 2018CID: 099001https://doi.org/10.1289/EHP4279AboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit The estimated exposure thresholds for RBC acetylcholinesterase (AChE) inhibition and plasma butyrylcholinesterase (BuChE) inhibition were listed incorrectly in the Results as “99% available RBC AChE, and 90% available plasma BuChE.” The correct values are 99.98% for available RBC AChE and 96.25% for available plasma BuChE.In addition, the RBC AChE level associated with a 15% cognitive deficit, based on data from Farahat et al. (2003), was derived incorrectly as BM sub RBC – AchE equals open parenthesis 100 minus 80 close parenthesis divided by 100 equals 0.20BMRBC–AChE=(100−80)/100=0.20. The correct value is BM sub RBC – AchE equals open parenthesis 100 minus 80 close parenthesis divided by 80 equals 0.25BMRBC–AChE=(100−80)/80=0.25. The estimate shown in the original Figure 5 for the level of BM sub AChEBMAChE associated with a 15% cognitive deficit in Farahat et al. (2003) also was incorrect. The corrected figure is included in this erratum.Figure 5. Predictions of human-specific cognitive deficits from measurable biomarkers of exposure. BM sub CPF, BM sub AChEBMCPF,BMAChE, and BM sub BuChEBMBuChE, are the independent biomarker of exposure variables for Equation 2 and correspond to peak plasma chlorpyrifos (CPF) concentration, minimum blood acetylcholinesterase (AChE) inhibition and minimum blood butyrylcholinesterase (BuChE) inhibition, respectively. Dashed lines represent 95% prediction intervals, and the solid circle (•) represents measured fractional cognitive deficit data from Farahat et al. (2003) using the differences in performance of the Benton Visual Retention Test between the exposed and unexposed groups and fractional plasma AChE activity from the reported plasma AChE activity.The authors confirm that these changes do not affect the study conclusions.The authors regret these errors.ReferenceFarahat TM, Abdelrasoul GM, Amr MM, Shebl MM, Farahat FM, Anger WK. 2003. Neurobehavioural effects among workers occupationally exposed to organophosphorous pesticides. Occup Environ Med 60(4):279–286, PMID: 12660376, 10.1136/oem.60.4.279. Crossref, Medline, Google ScholarFiguresReferencesRelatedDetailsRelated articlesA Novel Method for the Development of Environmental Public Health Indicators and Benchmark Dose Estimation Using a Health-Based End Point for Chlorpyrifos20 April 2018Environmental Health Perspectives Vol. 126, No. 9 September 2018Metrics About Article Metrics Publication History Manuscript received1 August 2018Manuscript accepted1 August 2018Originally published6 September 2018 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Evaluation of Serum Creatine Phosphokinase as a Marker of Severity in Organophosphorus Poisoning

Background &amp; Objectives: Organophosphorus (OP) poisoning is an important global health problem. Estimation of erythrocyte cholinesterase (EChE) and butyrylcholinesterase (BChE) as an evidence of OP poisoning is costly and not regularly performed. There are emerging options for new cheaper biochemical markers in relation to OP poisoning like creatine phosphokinase (CPK). The objectives of this study were to measure serum CPK level and correlate it with severity of poisoning, to evaluate clinical and prognostic significance of CPK in OP poisoning, to assess if serum CPK level can be used as an alternative of BChE level to stratify OP poisoning severity.Method: Total 100 patients of OP poisoning without any prior treatment, presenting within 12 hours, were selected and their clinical severity was categorized according to Peradeniya Organophosphorus Poisoning (POP) scale. Level of serum CPK, blood BChE and pH were measured and total dose of atropine required (mg) until final clinical outcome was calculated.Results: Out of 100, 43% patients had mild, 36% moderate and 21% severe clinical picture. There was a significant positive correlation between serum CPK value and requirement of atropine dose in patient with severe POP scale category and negative correlation with pH and serum cholinesterase levels, indicating that more severe the poisoning more will be serum CPK and requirement of atropine doses while less will be pH and serum cholinesterase, (p&lt;0.0001).Conclusions: This study suggests role of serum creatine kinase as surrogate, relatively cheap and easily quantifiable markers of severe OPC exposure and their association.

Investigation of the Esterase Status as a Complex Biomarker of Exposure to Organophosphorus Compounds

Development of biomarkers of human exposures to organophosphorus compounds OPCs and their quantification is a vital component of a system of prediction and early diagnostics of OPC-induced diseases. Our study was focused on investigation of esterase status as a complex biomarker of exposure to OPCs and an aid in accurate diagnosis. We suggest that this complex biomarker should be more effective and informative than standard assays of plasma butyrylcholinesterase (BChE), erythrocyte acetylcholinesterase (RBC AChE), and lymphocyte neuropathy target esterase (NTE). It will help: 1) to assess an exposure as such and to confirm the nonexposure of individuals suspected to have been exposed; 2) to determine if the exposure was to agents expected to produce acute and/or delayed neurotoxicity; 3) to perform dosimetry of the exposure, which provides valuable information for medical treatment. To confirm this hypothesis, we have examined the changes in activity of blood AChE, NTE, BChE and carboxylesterase (CaE) 1 h after i.p. administration of increasing doses of three OPCs with different esterase profiles: the known neuropathic compound O,O-dipropyl-O-dichlorovinyl phosphate (C3H 7O)2P(O)OCH=CCl2 (diPr-DClVP) as the control compound and two model dialkylphosphates (C2H5O)2P(O)OCH(CF3)2 (diEt-PFP) and (C4H9O)2P(O)OCH(CF3)2 (diBu-PFP). The esterases assay was performed in hemolysed blood by spectrophotometric (AChE, BChE, CaE) and biosensor (NTE) methods. Analysis of the obtained dose-dependences for blood esterases inhibition showed that blood BChE and CaE were the most sensitive biomarkers, allowing detection of low doses. Inhibition of blood NTE and AChE can be used to assess the likelihood that an exposure to OPC would produce cholinergic and/or delayed neuropathic effects.

Pesticide Application and Khat Chewing as Predictors of the Neurological Health Outcomes among Pesticide Applicators in a Vector Control Unit, Saudi Arabia.

Background: Pesticide applicators are at risk of developing neurological symptoms and neurobehavioral deficits. This risk may increase if the applicator chews stimulant plants like khat. Objective: To examine the sociodemographic and exposure determinants of neurological symptoms presentation, neurobehavioral performance, and cholinesterase activity among pesticide applicators in a vector control unit, Saudi Arabia. Methods: In a cross-sectional study, 30 pesticide applicators and 32 non-applicators from a vector control unit in Jazan region, Saudi Arabia, were studied. The study participants completed an exposure and medical questionnaire, and a neurobehavioral test battery. Their blood samples were also tested for the measurement of butyryl cholinesterase (BChE). Results: The mean blood BChE level was no significantly different between the applicators and non-applicators. Working in pesticide application and chewing khat were significant predictors of the neurological symptoms presentation and neurobehavioral deficits among the study participants. Each factor was associated with about 40% of the symptoms included in the questionnaire. Exposure to pyrethroids was significantly associated with a decrement in symbol digit test latency, tapping (TAP) non-preferred hand, and TAP alternating hands measures, representing the executive and motor speed/coordination functions. Khat chewing was associated with TAP preferred and non-preferred hands and serial digit learning measures, representing the memory and motor speed/coordination functions. Conclusion: It seems that being exposed to pyrethroids and chewing khat are associated with neurological and neurobehavioral drawbacks among pesticide applicators.

Post-exposure treatment with the oxime RS194B rapidly reverses early and advanced symptoms in macaques exposed to sarin vapor

Organophosphate (OP) nerve agents and pesticides trigger a common mechanism of neurotoxicity resulting from critical targeting and inhibition of acetylcholinesterases (AChE) in central and peripheral synapses in the cholinergic nervous system. Therapeutic countermeasures have thus focused on either administering an oxime post-exposure, that can rapidly reactivate OP-inhibited AChE, or by preventing OP poisoning through administering pre-exposure treatments that scavenge OPs before they inhibit their physiological AChE targets. While several pyridinium aldoxime antidotes are currently approved, their utility is impaired due to their inability to cross the blood-brain barrier (BBB) efficiently. The present study utilized a macaque (Ma) model to demonstrate the efficacy of a novel zwitterionic and centrally acting oxime RS194B to reactivate sarin- and paraoxon-inhibited macaque AChE and butyrylcholinesterase (BChE) in vitro and to further assess the capacity of RS194B to effect a reversal of clinical symptoms following sarin inhalation in vivo. In vitro, oxime reactivation of MaAChE and MaBChE was shown to be comparable to their human orthologs, while the macaque studies indicated that IM administration of 62.5 mg/kg of RS194B and 0.28 mg/kg atropine after continuous exposure to 49.6 μg/kg sarin vapor, rapidly reactivated the inhibited AChE and BChE in blood and reversed both early and advanced clinical symptoms of sarin-induced toxicity following pulmonary exposure within 1 h. The rapid cessation of autonomic and central symptoms, including convulsions, observed in macaques bodes well for the use of RS194B as an intra- or post-exposure human treatment and validates the macaque model in generating efficacy and toxicology data required for approval under the FDA Animal rule.

The impact of repeated organophosphorus pesticide exposure on biomarkers and neurobehavioral outcomes among adolescent pesticide applicators

ABSTRACTEgyptian adolescents are hired as seasonal workers to apply pesticides to the cotton crop and may perform this occupation for several years. However, few studies examined the effects of repeated pesticide exposure on health outcomes The goal of this study was to determine the impact of repeated pesticide exposure on neurobehavioral (NB) performance and biomarkers of exposure (urinary metabolite) and effect (cholinesterase activity). Eighty-four adolescents from two field stations in Menoufia, Egypt, were examined four times: before and during pesticide application season in 2010 and again before and during application season in 2011. At each of the four time points, participants completed a questionnaire, performed an NB test battery, and were assessed for urinary levels of the chlorpyrifos metabolite TCPy (3,5,6-trichloro-2-pyridinol) and blood cholinesterase activity. Following the study cohort over two consecutive pesticide application seasons revealed that TCPy levels significantly increased following exposure, and returned to baseline levels following the end of the application season. Blood butyryl cholinesterase activity exhibited a similar pattern. Although NB outcomes displayed learning and practice effects over time, deficits in performance were significantly associated with increased TCPy levels with reduction in the number of NB measures showing improvement over time. Biomarkers of exposure and effect demonstrated changes associated with pesticide application and recovery after application ended. Deficits in NB performance were correlated with elevated pesticide exposure. Data demonstrated that repeated pesticide exposure may exert a long-term adverse impact on human health.

Cord Blood Butyrylcholinesterase Activities in Normal Pregnant and Preeclamptic Women

Background: Human placenta, a non-neural tissue, contains cholinergic system and high-affinity muscarinic receptors. The role of cholinesterases (CE) in trophoblast function and pregnancy is not clear. Objectives: The present study aimed to analyze cholinesterase (CE) levels in cord blood in preeclamptic women. Methods: In the present study, maternal and cord blood butyrylcholinesterase levels were analyzed in women with preeclampsia (n = 25) and compared to those of normotensive pregnant women (n = 25) and normal, non-pregnant healthy controls (n = 25) by a kinetic method (the new DGKC method) using the AutoAnalyzer. Results: In the present study, maternal butyrylcholinesterase levels were lower in preeclamptics as compared to normotensive controls. Butyrylcholinesterase levels were lower in the cord blood of the babies of normotensives, amounting to 88.65% of the maternal levels. Cord blood butyrylcholinesterase levels were significantly lower in preeclamptic pregnant women as compared to normotensive pregnant women. On comparing these butyrylcholinesterase levels to the normal, non-pregnant control (Group III), it was observed that CE levels were significantly lower in both normotensive and preeclamptic women. Conclusions: The findings of the present study indicate that butyrylcholinesterase levels are lower in preeclamptics and that this might be due to the loss of muscarinic cholinergic receptors that occurs in preeclampsia.

In vitro antioxidant and cholinesterase inhibitory activities of methanolic fruit extract of Phyllanthus acidus.

BackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder clinically characterized by loss of memory and cognition. Cholinergic deficit and oxidative stress have been implicated in the pathogenesis of AD. Therefore, inhibition of acetylcholinesterase and oxidation are the two promising strategies in the development of drug for AD. Phyllanthus acidus, belonging to the family Euphorbiaceae, is a tree and has been used in traditional medicine to treat several pain, inflammatory and oxidative stress related disorders such as rheumatism, bronchitis, asthma, respiratory disorder, also important to promote intellect and enhance memory, thus supporting its possible anti-Alzheimer’s properties. In this study, P. acidus was evaluated for its cholinesterase inhibitory and antioxidant activities.MethodsIn this study, we evaluated the antioxidant potential and neuroprotective activity of P. acidus by assessing total phenol content (FCR assay), total flavonoid content, total antioxidant capacity, Fe3+ reducing power capacity, DPPH (2, 2-diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging capacity, lipid peroxidation inhibition activity & metal chelating activity. In addition acetylcholinestrase (AChE) and butyrylcholinestrase (BChE) inhibitory activities were performed using Ellman’s method.ResultsTotal phenolic content and total flavonoid content of the extract were 116.98 mg of gallic acid equivalent and 168.24 mg of quercetin equivalent per gm of dried extract. The methanolic extract of P. acidus (MEPA) showed considerable total antioxidant activity and reducing capacity. In DPPH scavenging assay and hydroxyl radical scavenging assay, the MEPA showed 84.33 % and 77.21 % scavenging having IC50 of 15.62 and 59.74 μg/ml respectively. In lipid peroxidation inhibition activity MEPA showed moderate inhibition of peroxidation at all concentrations with IC50 value of 471.63 μg/ml and exhibited metal chelating activity with IC50 value 308.67 μg/ml. The MEPA exhibited inhibition of rat brain acetylcholinesterase and human blood butyrylcholinesterase in a dose dependent manner and the IC50 value was found to be 1009.87 μg/ml and 449.51 μg/ml respectively.ConclusionThese results of the present study reveal that MEPA has considerable amount of antioxidant activity as well as anti-acetylcholinesterase and anti-butyrylcholinesterase activity which suggest its effectiveness against Alzheimer's disease and other neurodegenerative disorders.

Longitudinal assessment of occupational exposures to the organophosphorous insecticides chlorpyrifos and profenofos in Egyptian cotton field workers.

Chlorpyrifos (CPF) and profenofos (PFF) are organophosphorus (OP) insecticides that are applied seasonally in Egypt to cotton fields. Urinary trichloro-2-pyridinol (TCPy), a specific CPF metabolite, and 4-bromo-2-chlorophenol (BCP), a specific PFF metabolite, are biomarkers of exposure, while inhibition of blood butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) activities are effect biomarkers that may be associated with neurotoxicity. Urinary TCPy and BCP and blood BChE and AChE activities were measured in 37 adult Egyptian Ministry of Agriculture workers during and after 9-17 consecutive days of CPF application followed by an application of PFF (9-11 days), and a second CPF application (5 days) in 2008. During the OP applications, urinary TCPy and BCP levels were significantly higher than baseline levels, remained elevated following the application periods, and were associated with an exposure related inhibition of blood BChE and AChE. Analysis of blood AChE levels before and after the PFF application period suggests that individual workers with peak BCP levels greater than 1000 μg/g creatinine exhibited further inhibition of blood AChE with PFF application, demonstrating that PFF exposure had a negative impact on AChE activity in this highly exposed worker population. While large interindividual differences in exposure were observed throughout this longitudinal study (peak urinary BCP and peak TCPy levels for individuals ranging from 13.4 to 8052 and 16.4 to 30,107 μg/g creatinine, respectively), these urinary biomarkers were highly correlated within workers (r=0.75, p<0.001). This suggests that the relative exposures to CPF and PFF were highly correlated for a given worker. The variable exposures between job classification and work site suggest that job title and work location should not be used as the sole basis for categorizing OP exposures when assessing neurobehavioral and other health outcomes in Egyptian cotton field workers. Together, these findings will be important in educating the Egyptian insecticide application workers in order to encourage the development and implementation of work practices and personal protective equipment to reduce their exposure to CPF and PFF.

MELATONIN SECRETION AND SERUM BUTYRYLCHOLINESTERASE ACTIVITY AS A POTENTIAL BIOMARKERS OF COGNITIVE IMPAIRMENT IN ACUTE ISCHEMIC STROKE

The assessment of melatonin secretion in 25 men and serum butyrylcholinesterase level in 40 patients was performed in acute period of stroke. The interaction between these parameters and cognitive state was analyzed. The low levels of 6-sulfatoxymelatonin in daily urine and butyrylcholinesterase in blood were revealed. The 6-sulfatoxymelatonin level in daily urine &lt; 4,0 ng/ml can be regarded as a potential biological marker of poststoke memory dysfunction. The serum butyrylcholinesterase level &lt; 7,0 nmol/sec-l can be regarded as a potential biochemical marker of the multifunctional type of poststoke cognitive impairment.

Application of the buccal micronucleus cytome assay and analysis of PON1Gln192Arg and CYP2A6*9(−48T&gt;G) polymorphisms in tobacco farmers

Tobacco is a major Brazilian cash crop. Tobacco farmers apply large amounts of pesticides to control insect growth. Workers come into contact with green tobacco leaves during the tobacco harvest and absorb nicotine through the skin. In the present study, micronucleus frequency, cell death, and the frequency of basal cells were measured in tobacco farmers using the buccal micronucleus cytome assay (BMCyt), in parallel with measurement of blood butyrylcholinesterase (BChE) and nicotine levels. Polymorphisms in PONIGln192Arg and CYP2A6*9(-48T>G) were evaluated to verify the relationship between genetic susceptibility and the measured biomarkers. Peripheral blood and buccal cell samples were collected from 106 agricultural workers, at two different crop times (during pesticide application and leaf harvest), as well as 53 unexposed controls. BMCyt showed statistically significant increases in micronuclei, nuclear buds, and binucleated cells among exposed subjects in differentiated cells, and in micronuclei in basal cells. In addition, the exposed group showed higher values for condensed chromatin, karyorrhectic, pyknotic, and karyolitic cells, indicative of cell death, and an increase in the frequency of basal cells compared to the unexposed control group. A slight difference in mutagenicity using the BMCyt assay was found between the two different sampling times (pesticide application and leaf harvest), with higher micronucleus frequencies during pesticide application. Elevated cotinine levels were observed during the leaf harvest compared to the unexposed controls, while BChE level was similar among the farmers and controls. PONIGln192Arg and CYP2A6*9(-48T>G) polymorphisms were associated with DNA damage induced by pesticides and cell death.

Biomarkers of Chlorpyrifos Exposure and Effect in Egyptian Cotton Field Workers

BackgroundChlorpyrifos (CPF), a widely used organophosphorus pesticide (OP), is metabolized to CPF-oxon, a potent cholinesterase (ChE) inhibitor, and trichloro-2-pyridinol (TCPy). Urinary TCPy is often used as a biomarker for CPF exposure, whereas blood ChE activity is considered an indicator of CPF toxicity. However, whether these biomarkers are dose related has not been studied extensively in populations with repeated daily OP exposures.ObjectiveWe sought to determine the relationship between blood ChE and urinary TCPy during repeated occupational exposures to CPF.MethodsDaily urine samples and weekly blood samples were collected from pesticide workers (n = 38) in Menoufia Governorate, Egypt, before, during, and after 9–17 consecutive days of CPF application to cotton fields. We compared blood butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) activities with the respective urinary TCPy concentrations in each worker.ResultsAverage TCPy levels during the middle of a 1- to 2-week CPF application period were significantly higher in pesticide applicators (6,437 μg/g creatinine) than in technicians (184 μg/g) and engineers (157 μg/g), both of whom are involved in supervising the application process. We observed a statistically significant inverse correlation between urinary TCPy and blood BuChE and AChE activities. The no-effect level (or inflection point) of the exposure–effect relationships has an average urinary TCPy level of 114 μg/g creatinine for BuChE and 3,161 μg/g creatinine for AChE.ConclusionsOur findings demonstrate a dose–effect relationship between urinary TCPy and both plasma BuChE and red blood cell AChE in humans exposed occupationally to CPF. These findings will contribute to future risk assessment efforts for CPF exposure.

Chronic variable stress induces oxidative stress and decreases butyrylcholinesterase activity in blood of rats

Depressive disorders, including major depression, are serious and disabling, whose mechanisms are not clearly understood. Since life stressors contribute in some fashion to depression, chronic variable stress (CVS) has been used as an animal model of depression. In the present study we evaluated some parameters of oxidative stress [thiobarbituric acid reactive substances (TBARS), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)], and inflammatory markers (interleukin 6, C reactive protein, tumor necrosis factor-alpha and nitrites), as well as the activity of butyrylcholinesterase in blood of rats subjected to chronic stress. Homocysteine and folate levels also were measured. Stressed animals were submitted to different mild stressors for 40 days. After CVS, a reduction in weight gain was observed in the stressed group, as well as an increase in immobility time in the forced swimming test as compared with controls. Stressed animals presented a significant increase on TBARS and SOD/CAT ratio, but stress did not alter GPx activity and any inflammatory parameters studied. CVS caused a significant inhibition on serum butyrylcholinesterase activity. Stressed rats had higher plasmatic levels of homocysteine without differences in folate levels. Although it is difficult to extrapolate our findings to the human condition, the alterations observed in this work may be useful to help to understand, at least in part, the pathophysiology of depressive disorders.

Fetal effects of environmental exposure of pregnant women to organophosphorus compounds in a rural farming community in Sri Lanka

Background. The possible deleterious effects of low-grade, chronic environmental and occupational exposure to organophosphorus compounds (OPCs) are not well documented. Objective. To investigate the possible effects of low-level, chronic exposure of pregnant mothers to OPCs on the fetus by measuring OPC levels, and using markers of OPC exposure, oxidative stress and oxidative tissue damage. Methods. Toxicity was assessed by measuring (i) OPC levels in breast milk and plasma from maternal and cord blood using gas chromatography, (ii) maternal and fetal butyrylcholinesterase (BChE) activity using inhibition assays, (iii) antioxidant status of the fetus using superoxide dismutase activity assays, (iv) oxidative stress in the fetus by determining malondialdehyde (MDA) concentrations, and (v) examining for fetal DNA fragmentation using electrophoresis. Samples were obtained from consenting mothers living in a farming community in southern Sri Lanka at the end of the pesticide spray season (study group) and just before the commencement of the spray season (in-between spray season; control group). Results. Organophosphate residues were detected in only two subjects (chlorpyrifos in maternal and cord blood of one during the spray season and dimethoate in breast milk of another during the in between spray season), but the test employed was capable of only detecting concentrations above 0.05mg/l. However, cord blood obtained during the spray season showed significant inhibition of BChE activity, increased oxidative stress and more DNA fragmentation when compared with cord blood obtained during the in-between spray season. Conclusions. Inhibition of cord blood BChE activity indicates fetal exposure to organophosphorus compounds during times when there is a high probability of environmental drift. This provides a plausible explanation for the increased oxidative stress and high DNA fragmentation in the fetus. Long-term outcomes of such exposures are unknown.

Rapid method for evaluation of cholinesterase inhibitors

The fluorescence intensity of reversible inhibitor ethidium bromide fluorophore complex with equine blood butyryl cholinesterase decreases in the presence of inhibitor (tacrine) not fluorescing in the visible spectrum. An express method for tacrine evaluation is developed.

Blood Acylpeptide Hydrolase Activity Is a Sensitive Marker for Exposure to Some Organophosphate Toxicants

Acylpeptide hydrolase (APH) unblocks N-acetyl peptides. It is a major serine hydrolase in rat blood, brain, and liver detected by derivatization with (3)H-diisopropyl fluorophosphate (DFP) or a biotinylated fluorophosphonate. Although APH does not appear to be a primary target of acute poisoning by organophosphorus (OP) compounds, the inhibitor specificity of this secondary target is largely unknown. This study fills the gap and emphasizes blood APH as a potential marker of OP exposure. The most potent in vitro inhibitors for human erythrocyte and mouse brain APH are DFP (IC(50) 11-17 nM), chlorpyrifos oxon (IC(50) 21-71 nM), dichlorvos (IC(50) 230-560 nM), naled (IC(50) 370-870 nM), and their analogs with modified alkyl substituents. (3)H-diisopropyl fluorophosphate is a potent inhibitor of mouse blood and brain APH in vivo (ED(50) 0.09-0.2 mg/kg and 0.02-0.03 mg/l for ip and vapor exposure, respectively). Mouse blood and brain APH and blood butyrylcholinesterase (BChE) are of similar sensitivity to DFP in vitro and in vivo (ip and vapor exposure), but APH inhibition is much more persistent in vivo (still >80% inhibition after 4 days). The inhibitory potency of OP pesticides in vivo in mice varies from APH selective (dichlorvos, naled, and trichlorfon), to APH and BChE selective (profenofos and tribufos), to ChE selective or nonselective (many commercial insecticides). Sarin administered ip at a lethal dose to guinea pigs inhibits blood acetylcholinesterase and BChE completely but erythrocyte APH only partially. Blood APH activity is therefore a sensitive marker for exposure to some but not all OP pesticides and chemical warfare agents.