Biomonitoring of Pesticides: Pharmacokinetics of Organophosphorus and Carbamate Insecticides

Timchalk, Charles

doi:10.1002/9780470640500.ch19

Cited by 3 publications

(3 citation statements)

References 121 publications

(187 reference statements)

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“…Although maternal organophosphate exposure levels in the prenatal period and postpartum were higher in the CHAMACOS than in the general population (Bradman, et al, 2005), no exposure data is available for mothers and children at the age 9 visit. Another limitation of our study is the lack of baseline (pre-exposure) measurements for cholinesterase activities such as those typically measured for occupational biomonitoring (Timchalk, 2011). …”

Section: Discussionmentioning

confidence: 99%

“…Both acetylcholinesterase and butyrylcholinesterase can be irreversibly inactivated by organophosphate-oxon metabolites. Depression of acetylcholinesterase and butyrylcholinesterase activity in the blood is a validated biomarker of organophosphate pesticide exposure and is used to monitor occupational exposures (See Timchalk, 2011 for review).…”

Section: Introductionmentioning

confidence: 99%

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Cholinesterase and paraoxonase (PON1) enzyme activities in Mexican–American mothers and children from an agricultural community

González

Huen

Venkat

et al. 2012

J Expo Sci Environ Epidemiol

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Exposure to organophosphate and carbamate pesticides can lead to neurotoxic effects through inhibition of cholinesterase enzymes. The paraoxonase (PON1) enzyme can detoxify oxon derivatives of some organophosphates. Lower PON1, acetylcholinesterase, and butyrylcholinesterase activities have been reported in newborns relative to adults, suggesting increased susceptibility to organophosphate exposure in young children. We determined PON1, acetylcholinesterase, and butyrylcholinesterase activities in Mexican-American mothers and their 9-year-old children (n=202 pairs) living in an agricultural community in California. We used paired t-tests to compare enzymatic activities among mothers and their children and analysis of variance to determine which factors are associated with enzyme activities. Substrate-specific PON1 activities were slightly lower in children than their mothers; however, these differences were not statistically significant. We observed significantly lower acetylcholinesterase but higher butyrylcholinesterase levels in children compared to their mothers. Mean butyrylcholinesterase levels were strongly associated with child obesity status (BMI Z scores >95%). We observed highly significant correlations among mother-child pairs for each of the enzymatic activities analyzed; however, PON1 activities did not correlate with acetylcholinesterase or butyrylcholinesterase activities. Our findings suggest that by age nine, PON1 activities approach adult levels and host factors including sex and obesity may affect key enzymes involved in pesticide metabolism.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cholinesterase and paraoxonase (PON1) enzyme activities in Mexican–American mothers and children from an agricultural community

González

Huen

Venkat

et al. 2012

J Expo Sci Environ Epidemiol

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“…The ADME of OP and CM insecticides in animals have been described (Tomokuni et al, 1985;Gupta, 1994;Wu et al, 1996;Timchalk, 2006Timchalk, , 2010. These insecticides gain entry into the body mainly through oral, dermal or inhalation exposure.…”

Section: Pharmacokinetics Of Ops and Cmsmentioning

confidence: 97%

Organophosphates and carbamates

Gupta¹,

Milatović²

2012

Veterinary Toxicology

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Prognostic Value of Insecticide Type and Enzymatic Activities on Severity of Acute Insecticides Poisoning

El-moneim

Al-Maghraby

Abd-El-hameed

et al. 2019

The Egyptian Journal of Forensic Sciences and Applied Toxicolog

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Background: Insecticides poisoning is a major problem worldwide, especially in developing countries. The most extensively utilized types are pseudocholinesterase (PChE) inhibitors, predominantly organophosphorus compounds and carbamates. They are metabolized by microsomal oxidases to oxygen analogues, which are active neurotoxic metabolites. These oxygen analogues are further hydrolyzed by the serum arylesterase; paraoxonase (PON1), which appears to play a pivotal role in their detoxification. Objectives: This study aimed to 1-Identification and quantitation of common insecticides in acutely poisoned patients presented to Assiut University hospitals. 2-Detection of paraoxonase and cholinesterase levels in poisoned patients. 3-Evaluate the prognostic value of pesticide type and enzymes level in relation to the severity of insecticidal poisoning. Methods: This casecontrol study was conducted on 50 patients who have been admitted to the Emergency Unit and Intensive Care Units in Assiut University Hospitals along with 50 controls. Age, residence and sex were matched. History and clinical data and other related laboratory investigations were gathered for each patient. Blood plasma samples (5ml) were collected from patients on admission alongside controls then analyzed for level of pseudocholinesterase (PChE) and paraoxonase (PON1) enzymes activity by a spectrophotometer. The insecticide types were identified using Gas Chromatography/Mass spectrometry (GC-MS). Results: The patients were mostly males, of young age group and residing in rural areas. The mode of poisoning was mainly accidental by oral route (66%). Tachycardia, tachypnea and hypotension were most commonly presenting muscarinic signs. The detected insecticides were mainly of the organophosphate types specifically malathion. A highly significant decrease in PChE and PON1 level were detected in patients compared to controls that the decline in their levels was also significantly associated with the severity of acute poisoning. A positive correlation was also observed between PChE and PON1 levels. Conclusion: the present study identified more than one type of pesticides mainly of organophosphate category among acutely poisoned patients. Furthermore, it pointed to those persons with higher paraoxonase activity and less cholinesterase inhibition may have a better chance of toxic effects amelioration.

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Biomonitoring of Pesticides: Pharmacokinetics of Organophosphorus and Carbamate Insecticides

Cited by 3 publications

References 121 publications

Cholinesterase and paraoxonase (PON1) enzyme activities in Mexican–American mothers and children from an agricultural community

Cholinesterase and paraoxonase (PON1) enzyme activities in Mexican–American mothers and children from an agricultural community

Organophosphates and carbamates

Prognostic Value of Insecticide Type and Enzymatic Activities on Severity of Acute Insecticides Poisoning

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