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Ramadori GP. Organophosphorus Poisoning: Acute Respiratory Distress Syndrome (ARDS) and Cardiac Failure as Cause of Death in Hospitalized Patients. Int J Mol Sci 2023; 24:ijms24076658. [PMID: 37047631 PMCID: PMC10094912 DOI: 10.3390/ijms24076658] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/22/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
Industrial production of food for animals and humans needs increasing amounts of pesticides, especially of organophosphates, which are now easily available worldwide. More than 3 million cases of acute severe poisoning are estimated to occur worldwide every year, and even more cases remain unreported, while 200,000–350,000 incidentally or intentionally poisoned people die every year. Diagnostic and therapeutic procedures in organophosphate poisoning have, however, remained unchanged. In addition to several neurologic symptoms (miosis, fasciculations), hypersecretion of salivary, bronchial, and sweat glands, vomiting, diarrhea, and loss of urine rapidly induce dehydration, hypovolemia, loss of conscience and respiratory distress. Within hours, signs of acidosis due to systemic hypoxia can be observed at first laboratory investigation after hospitalization. While determination of serum-cholinesterase does not have any diagnostic value, it has been established that hypoalbuminemia alone or accompanied by an increase in creatinine, lactate, or C-reactive protein serum levels has negative prognostic value. Increased serum levels of C-reactive protein are a sign of systemic ischemia. Protective mechanical ventilation should be avoided, if possible. In fact, acute respiratory distress syndrome characterized by congestion and increased weight of the lung, accompanied by heart failure, may become the cause of death. As the excess of acetylcholine at the neuronal level can persist for weeks until enough newly, locally synthesized acetylcholinesterase becomes available (the value of oximes in reducing this time is still under debate), after atropine administration, intravenous albumin and fluid infusion should be the first therapeutic interventions to reestablish normal blood volume and normal tissue oxygenation, avoiding death by cardiac arrest.
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Ribeiro AC, Hawkins E, Jahr FM, McClay JL, Deshpande LS. Repeated exposure to chlorpyrifos is associated with a dose-dependent chronic neurobehavioral deficit in adult rats. Neurotoxicology 2022; 90:172-183. [DOI: 10.1016/j.neuro.2022.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/16/2022] [Accepted: 03/25/2022] [Indexed: 11/16/2022]
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Pesticides, cognitive functions and dementia: A review. Toxicol Lett 2020; 326:31-51. [PMID: 32145396 DOI: 10.1016/j.toxlet.2020.03.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/13/2022]
Abstract
Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hormetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.
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Zeigelboim BS, Malisky JS, Rosa MRD, Lacerda ABMD, Alcaraz PDS, Fonseca VR. The Importance of Otoneurological Evaluation in Brazilian Workers Exposed to Pesticides: A Preliminary Study. Int Arch Otorhinolaryngol 2019; 23:e389-e395. [PMID: 31649757 PMCID: PMC6805213 DOI: 10.1055/s-0039-1684009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/13/2019] [Indexed: 11/13/2022] Open
Abstract
Introduction
Agrochemicals, also known as pesticides, are widely used in agriculture and in public health. They are organic and inorganic chemical substances with a high level of toxicity not only for the environment, but also for human health.
Objective
To verify findings on labyrinthine assessment in endemic disease control agents, and to recommend the inclusion of the vestibular exam in the set of tests for pesticide-exposed populations.
Methods
Descriptive, prospective, cross-sectional study with a sample comprising 15 endemic disease control agents, males, mean age of 51.6 years old (standard deviation [SD] = 5.9). All of the participants were submitted to anamnesis, otorhinolaryngological screening, and vestibular assessment.
Results
Regarding the most reported complaints, dizziness (73.4%), headache (60%), and tingling in the extremities (53.4%) were observed. The findings of the vestibular exams were normal in 53.3%, while 46.7% showed peripheral vestibular disorder, of which 26.7% were of deficitary type, and 20% of the irritative type.
Conclusions:
Alteration in the vestibular system was verified in 50% of the workers, with a greater prevalence in the caloric testing. Several disorders related to pesticides intoxication are scientifically known. Actions promoting knowledge and qualification of this population for the proper handling of chemicals are suggested, in addition to the elaboration and inclusion of protocols of vestibular assessment in hearing health programs for the prevention, diagnosis and treatment of vestibular disorders.
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Affiliation(s)
- Bianca Simone Zeigelboim
- Department of Otoneurology, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil.,Post-Graduate Program in Communication Disorders, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil
| | | | | | - Adriana Bender Moreira de Lacerda
- Department of Otoneurology, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil.,Post-Graduate Program in Communication Disorders, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil
| | - Patrícia de Souza Alcaraz
- Post-Graduate Program in Communication Disorders, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil.,Department of Audiology, Universidade do Oeste Paulista, Presidente Prudente, SP, Brazil
| | - Vinicius Ribas Fonseca
- Department of Otoneurology, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil.,Post-Graduate Program in Communication Disorders, Universidade Tuiuti do Paraná, Curitiba, PR, Brazil.,Department of Otorhinolaryngology, Hospital da Cruz Vermelha Brasileira, Curitiba, PR, Brazil
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Thompson CM, Gerdes JM, VanBrocklin HF. Positron emission tomography studies of organophosphate chemical threats and oxime countermeasures. Neurobiol Dis 2019; 133:104455. [PMID: 31022458 DOI: 10.1016/j.nbd.2019.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/28/2019] [Accepted: 04/19/2019] [Indexed: 01/31/2023] Open
Abstract
There is a unique in vivo interplay involving the mechanism of inactivation of acetylcholinesterase (AChE) by toxic organophosphorus (OP) compounds and the restoration of AChE activity by oxime antidotes. OP compounds form covalent adducts to this critical enzyme target and oximes are introduced to directly displace the OP from AChE. For the most part, the in vivo inactivation of AChE leading to neurotoxicity and antidote-based therapeutic reversal of this mechanism are well understood, however, these molecular-level events have not been evaluated by dynamic imaging in living systems at millimeter resolution. A deeper understanding of these critically, time-dependent mechanisms is needed to develop new countermeasures. To address this void and to help accelerate the development of new countermeasures, positron-emission tomography (PET) has been investigated as a unique opportunity to create platform technologies to directly examine the interdependent toxicokinetic/pharmacokinetic and toxicodynamic/pharmacodynamic features of OPs and oximes in real time within live animals. This review will cover two first-in-class PET tracers representing an OP and an oxime antidote, including their preparation, requisite pharmacologic investigations, mechanistic interpretations, biodistribution and imaging.
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Affiliation(s)
- Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA.
| | - John M Gerdes
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT 59812, USA
| | - Henry F VanBrocklin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco 185 Berry St. Suite 350, San Francisco, CA 94107, USA
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Khan N, Kennedy A, Cotton J, Brumby S. A Pest to Mental Health? Exploring the Link between Exposure to Agrichemicals in Farmers and Mental Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E1327. [PMID: 31013861 PMCID: PMC6517992 DOI: 10.3390/ijerph16081327] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/08/2019] [Accepted: 04/09/2019] [Indexed: 01/20/2023]
Abstract
The current literature acknowledges that occupational exposures can adversely affect mental health. This review seeks to elucidate the current understanding of the effect of agrichemical exposure on mental health in the agricultural sector, including low-dose, chronic pesticide exposure. This scoping review adopted a snowballing and saturation approach. The review highlights inconsistencies in linking poor mental health and pesticide use. While some studies specifically showed that both high- and low-dose pesticide exposure were associated with poor mental health, consistent and rigorous research methods are lacking. The review also proposes terms to delineate exposure types described in the literature. The review outcomes direct efforts to protect the health, wellbeing and safety of farming communities across the globe.
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Affiliation(s)
- Nufail Khan
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3216, Australia.
- National Centre for Farmer Health, Western District Health Service, Hamilton, VIC 3300, Australia.
| | - Alison Kennedy
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3216, Australia.
- National Centre for Farmer Health, Western District Health Service, Hamilton, VIC 3300, Australia.
| | - Jacqueline Cotton
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3216, Australia.
- National Centre for Farmer Health, Western District Health Service, Hamilton, VIC 3300, Australia.
| | - Susan Brumby
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, VIC 3216, Australia.
- National Centre for Farmer Health, Western District Health Service, Hamilton, VIC 3300, Australia.
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Harrison V, Mackenzie Ross S. Anxiety and depression following cumulative low-level exposure to organophosphate pesticides. ENVIRONMENTAL RESEARCH 2016; 151:528-536. [PMID: 27575752 DOI: 10.1016/j.envres.2016.08.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/19/2016] [Accepted: 08/17/2016] [Indexed: 05/03/2023]
Abstract
Previous research suggests that individuals with a prior history of pesticide poisoning are at increased risk of psychiatric disorder (Freire and Koifman, 2013), but findings regarding the impact of cumulative low-level exposure are inconsistent. The aim of the current study was to investigate whether sheep farmers with a history of low-level exposure to organophosphate pesticides (1) report a higher level of psychological distress on subjective symptom questionnaires, compared to unexposed controls (2) also meet internationally agreed diagnostic criteria for a psychiatric disorder more often than unexposed controls. 127sheep farmers were evaluated and compared to 78 unexposed controls, matched in terms of gender, education, level of intelligence, working status and area of residence. Both self-report measures and structured clinical interviews were used to assess mental health. The exposed cohort reported significantly higher rates of anxiety and depression when self-report questionnaires were used to evaluate mood, even when stressful life events, demographic and physical health factors were taken into account. However, when diagnostic interviews were used to assess mood, this pattern only held true for anxiety.
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Affiliation(s)
- Virginia Harrison
- Department of Psychology, Open University, Walton Hall, Milton Keynes MK76AA, UK.
| | - Sarah Mackenzie Ross
- Research Department of Clinical, Educational & Health Psychology, University College London, Gower Street, London WC1E 6BT, UK
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Abstract
OBJECTIVE Farmworkers experience significant work-related health risks including pesticide-associated cognitive impairment. Practice effect is a surrogate for learning ability. This study examined differences in cognitive function and learning capacity in Latino farmworkers and nonfarmworkers. METHODS Tasks of learning and short-term memory, executive function and working memory, perceptual coding, and psychomotor function were assessed at baseline and 3-month follow-up in 136 farmworkers and 116 nonfarmworkers. RESULTS Farmworkers had better performance on visuospatial learning and short-term memory at baseline (P < 0.05). Nevertheless, nonfarmworkers showed more practice effects, or improvement on cognitive performance, at 3-month follow-up relative to farmworkers. Furthermore, the amount of improvement on visuospatial learning ability, short-term visuospatial memory, and perceptual coding ability was significantly higher in nonfarmworkers than in farmworkers. CONCLUSIONS Practice effects may serve as an additional cognitive readout to differentiate healthy individuals from those with cognitive impairment.
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Muñoz-Quezada MT, Lucero BA, Iglesias VP, Muñoz MP, Cornejo CA, Achu E, Baumert B, Hanchey A, Concha C, Brito AM, Villalobos M. Chronic exposure to organophosphate (OP) pesticides and neuropsychological functioning in farm workers: a review. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2016; 22:68-79. [PMID: 27128815 PMCID: PMC4894272 DOI: 10.1080/10773525.2015.1123848] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Previous studies have demonstrated that acute poisoning from exposure to organophosphate (OP) pesticides in agricultural workers causes adverse health effects. However, neuropsychological and cognitive effects of chronic occupational exposure to OP pesticides remain controversial. OBJECTIVE To identify, evaluate, and systematize existing evidence regarding chronic exposure to OP pesticides and neuropsychological effects in farmworkers. METHODS Using the PubMed search engine, a systematic review process was implemented and replicated according to the PRISMA statement. Eligibility criteria included workers over 18 years of age exposed to OP pesticides as well as assessment of neuropsychological and cognitive functioning. Search terms were in English and Spanish languages and included organophosphate and workers. RESULTS Of the search results, 33 of 1,256 articles meet eligibility criteria. Twenty-four studies found an association between chronic occupational exposure to OP pesticides and low neuropsychological performance in workers. We classified nine of the studies to have study design limitations. Studies indicated occupational exposure to OP pesticides is linked to difficulties in executive functions, psychomotor speed, verbal, memory, attention, processing speed, visual-spatial functioning, and coordination. Nine studies find no relationship between OP pesticides exposure and neuropsychological performance. CONCLUSIONS Overall, evidence suggests an association between chronic occupational exposure to OP pesticides and neuropsychological effects. However, there is no consensus about the specific cognitive skills affected.
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Affiliation(s)
| | | | | | - María Pía Muñoz
- School of Public Health, University of Chile, Santiago, Chile
| | | | - Eduardo Achu
- Faculty of Health Sciences, Catholic University of Maule, Talca, Chile
| | - Brittney Baumert
- College of Public Health, University of Georgia, Athens, GA, USA
| | - Arianna Hanchey
- College of Public Health, University of Georgia, Athens, GA, USA
| | - Carlos Concha
- Regional Secretary of Ministry of Health, Talca, Chile
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Zhang X, Wu M, Yao H, Yang Y, Cui M, Tu Z, Stallones L, Xiang H. Pesticide poisoning and neurobehavioral function among farm workers in Jiangsu, People's Republic of China. Cortex 2015; 74:396-404. [PMID: 26475098 DOI: 10.1016/j.cortex.2015.09.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/24/2015] [Accepted: 09/03/2015] [Indexed: 02/04/2023]
Abstract
Pesticides remain an integral part of agricultural activities worldwide. Although there have been a number of studies over the last two decades concerning the adverse effects of pesticide poisoning and chronic long term exposures on neurobehavioral function, the impact of recent pesticide poisoning and long term pesticide exposure on neurobehavioral function in Chinese farm workers has not been reported. China is the largest user of pesticides worldwide and figures suggest 53,300-123,000 Chinese people are poisoned every year. A case control study was conducted to examine the impact of recent pesticide poisoning on neurobehavioral function and the relationship between years worked in agriculture and lower performance on neurobehavioral tests. A total of 121 farm workers who self-reported recent pesticide poisonings within the previous 12 months (case group) and 80 farm workers who reported no pesticide poisoning in the previous 12 months (control group) were recruited from three areas of Jiangsu Province, China. The World Health Organization (WHO) recommended neurobehavioral core test battery (NCTB) was used to assess neurobehavioral functioning among cases and controls. Student's t tests and two-way covariance analysis (ANCOVA) were used to test for significant differences in the neurobehavioral test results between the groups. Scores on the Profile of Mood States (POMS) in the recently poisoned group were significantly higher for anger-hostility, depression-dejection, tension-anxiety and lower for vigor-activity compared to controls (p < .05). Digit span, digit symbol, Benton visual retention and pursuit aiming scores were all significantly lower among the recently poisoned group compared to the controls (p < .05). Two-way ANCOVA indicated significantly lower performance in correct pursuit aiming and higher error pursuit aiming amongst the recently poisoned group and those who had worked for more than 30 years in agriculture (p < .05). These findings provide important preliminary epidemiological evidence regarding the association between occupational pesticide exposure and neurobehavioral functioning in Chinese farm workers.
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Affiliation(s)
- Xujun Zhang
- Injury Prevention Research Institute, School of Public Health, Southeast University, Nanjing, Jiangsu Province, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu Province, China.
| | - Ming Wu
- Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, Jiangsu Province, China
| | - Hongyan Yao
- Office of Epidemiology, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yaming Yang
- Yixing Center for Disease Control and Prevention, Yixing, Jiangsu Province, China
| | - Mengjing Cui
- Injury Prevention Research Institute, School of Public Health, Southeast University, Nanjing, Jiangsu Province, China
| | - Zhibin Tu
- Nanchang Center for Disease Control and Prevention, Nanchang, Jiangsu Province, China
| | - Lorann Stallones
- Colorado Injury Control Research Center, Colorado State University, Fort Collins, CO, USA
| | - Huiyun Xiang
- Center for Injury Research and Policy and Center for Pediatric Trauma Research, The Research Institute at Nationwide Children's Hospital, The Ohio State University College of Medicine, Columbus, OH, USA
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Salivary acetylcholinesterase activity is increased in Parkinson's disease: a potential marker of parasympathetic dysfunction. PARKINSONS DISEASE 2015; 2015:156479. [PMID: 25767737 PMCID: PMC4342069 DOI: 10.1155/2015/156479] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/24/2015] [Indexed: 11/22/2022]
Abstract
Introduction. Decreased salivary flow and xerostomia are frequent findings in Parkinson's disease (PD), possibly caused by alterations in the parasympathetic tonus. Here we explore salivary acetylcholinesterase (AChE) activity as a potential biomarker in PD. Methods. We measured salivary flow, AChE activity, and total protein concentration in 30 PD patients and 49 healthy controls. We also performed exploratory correlation analyses with disease duration, motor symptom severity, autonomic complaints, and other nonmotor symptoms. Results. PD patients displayed significantly decreased salivary flow rate, significantly increased salivary AChE activity, and total protein concentration. Importantly, the AChE activity/total protein ratio was significantly increased in PD patients, suggesting that increased AChE activity cannot be explained solely by upconcentration of saliva. The Unified PD Rating Scale (UPDRS) score displayed significant correlation with total salivary protein (P = 0.002) and near-significant correlation with salivary flow (P = 0.07). Color vision test scores were also significantly correlated with AChE activity (P = 0.04) and total protein levels (P = 0.002). Conclusion. Salivary AChE activity is increased in PD patients compared to healthy controls. Future studies are needed to elucidate whether this parameter reflects the extent of neuronal damage and parasympathetic denervation in the salivary glands of PD patients.
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Meyer-Baron M, Knapp G, Schäper M, van Thriel C. Meta-analysis on occupational exposure to pesticides--neurobehavioral impact and dose-response relationships. ENVIRONMENTAL RESEARCH 2015; 136:234-45. [PMID: 25460642 DOI: 10.1016/j.envres.2014.09.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/01/2014] [Accepted: 09/16/2014] [Indexed: 05/22/2023]
Abstract
While the health impact of high exposures to pesticides is acknowledged, the impact of chronic exposures in the absence of acute poisonings is controversial. A systematic analysis of dose-response relationships is still missing. Its absence may provoke alternative explanations for altered performances. Consequently, opportunities for health prevention in the occupational and environmental field may be missed. Objectives were (1) quantification of the neurotoxic impact of pesticides by an analysis of functional alterations in workers measured by neuropsychological performance tests, (2) estimates of dose-response relationships on the basis of exposure duration, and (3) exploration of susceptible subgroups. The meta-analysis employed a random effects model to obtain overall effects for individual performance tests. Twenty-two studies with a total of 1758 exposed and 1260 reference individuals met the inclusion criteria. At least three independent outcomes were available for twenty-six performance variables. Significant performance effects were shown in adults and referred to both cognitive and motor performances. Effect sizes ranging from dRE=-0.14 to dRE=-0.67 showed consistent outcomes for memory and attention. Relationships between effect sizes and exposure duration were indicated for individual performance variables and the total of measured performances. Studies on adolescents had to be analyzed separately due to numerous outliers. The large variation among outcomes hampered the analysis of the susceptibility in this group, while data on female workers was too scant for the analysis. Relationships exist between the impact of pesticides on performances and exposure duration. A change in test paradigms would help to decipher the impact more specifically. The use of biomarkers appropriate for lower exposures would allow a better prevention of neurotoxic effects due to occupational and environmental exposure. Intervention studies in adolescents seem warranted to specify their risk.
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Affiliation(s)
- Monika Meyer-Baron
- IfADo - Leibniz Research Centre for Working Environment and Human Factors, Research Group: Neurotoxicology and Chemosensation, Ardeystr. 67, D-44139 Dortmund, Germany.
| | - Guido Knapp
- TU Dortmund University, Department of Statistics, Vogelpothsweg 87, D-44227 Dortmund, Germany
| | - Michael Schäper
- IfADo - Leibniz Research Centre for Working Environment and Human Factors, Research Group: Neurotoxicology and Chemosensation, Ardeystr. 67, D-44139 Dortmund, Germany
| | - Christoph van Thriel
- IfADo - Leibniz Research Centre for Working Environment and Human Factors, Research Group: Neurotoxicology and Chemosensation, Ardeystr. 67, D-44139 Dortmund, Germany
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Ophir A, Karakis I, Richter E, Abarbanel J, Wormser U, Aschner M, Finkelstein Y. An uncommon pattern of polyneuropathy induced by lifetime exposures to drift containing organophosphate pesticides. Neurotoxicology 2014; 45:338-46. [DOI: 10.1016/j.neuro.2014.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 06/04/2014] [Accepted: 08/05/2014] [Indexed: 11/28/2022]
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Belabassi Y, Chao CK, Holly R, George KM, Nagy JO, Thompson CM. Preparation and characterization of diethoxy- and monoethoxy phosphylated ('aged') serine haptens and use in the production of monoclonal antibodies. Chem Biol Interact 2014; 223:134-40. [PMID: 25261769 DOI: 10.1016/j.cbi.2014.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/17/2014] [Accepted: 09/12/2014] [Indexed: 11/27/2022]
Abstract
In this study, the first mechanism-based monoclonal antibodies have been produced that recognize and differentiate diethoxy- and monoethoxyphosphorylated serine residues. Haptens were synthesized as the stable phosphonate form of phosphoserine esters to improve the immunoresponse. Following condensation with a glutaric anhydride to link the phosphoserine moieties to carrier protein, the hapten densities attached to bovine serum albumin and keyhole limpet henocyanin were determined by partial trypsin digestion and MALDI mass spectrometry, and confirmed using a fluorescent assay (FITC) to quantify unmodified lysine residues. The conjugation reactions were pH optimized to improve hapten density. Screening of subclones led to the identification of two monoclonal antibodies: (a) N257/25.11 that specifically recognizes (EtO)2P(O)-Ser as the phosphylated or inhibited form, and (b) N262/16 that recognizes (EtO)(HO)P(O)-Ser as the 'aged' form. Analysis of blood samples treated with paraoxon (EtO)2P(O)-OPhNO2 showed a concentration dependent recognition of the phosphylated form.
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Affiliation(s)
- Yamina Belabassi
- ATERIS Technologies LLC, 901 N Orange Street, Missoula, MT 59802, USA
| | - Chih-Kai Chao
- ATERIS Technologies LLC, 901 N Orange Street, Missoula, MT 59802, USA
| | - Ryan Holly
- ATERIS Technologies LLC, 901 N Orange Street, Missoula, MT 59802, USA
| | - Kathleen M George
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT 59812, USA
| | - Jon O Nagy
- ATERIS Technologies LLC, 901 N Orange Street, Missoula, MT 59802, USA
| | - Charles M Thompson
- ATERIS Technologies LLC, 901 N Orange Street, Missoula, MT 59802, USA; Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, MT 59812, USA.
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Kaur S, Singh S, Chahal KS, Prakash A. Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity. Can J Physiol Pharmacol 2014; 92:893-911. [DOI: 10.1139/cjpp-2014-0113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.
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Affiliation(s)
- Shamsherjit Kaur
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
- Punjab Technical University, Kapurthala 144601, Punjab, India
| | - Satinderpal Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Karan Singh Chahal
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Atish Prakash
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
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Karami-Mohajeri S, Nikfar S, Abdollahi M. A systematic review on the nerve–muscle electrophysiology in human organophosphorus pesticide exposure. Hum Exp Toxicol 2013; 33:92-102. [DOI: 10.1177/0960327113489047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This article presents a systematic review of the recent literature on the scientific support of electromyography (EMG) and nerve conduction velocity (NCV) in diagnosing the exposure and toxicity of organophosphorus pesticides (OP). Specifically, this review focused on changes in EMG, NCV, occurrence of intermediate syndrome (IMS), and OP-induced delayed polyneuropathy (OPIDN) in human. All relevant bibliographic databases were searched for human studies using the key words “OP poisoning”, “electromyography”, “nerve conduction study,” and “muscles disorders”. IMS usually occurs after an acute cholinergic crisis, while OPIDN occurs after both acute and chronic exposures. Collection of these studies supports that IMS is a neuromuscular junction disorder and can be recorded upon the onset of respiratory failure. Due to heterogeneity of reports on outcomes of interest such as motor NCV and EMG amplitude in acute cases and inability to achieve precise estimation of effect in chronic cases meta-analysis was not helpful to this review. The OPIDN after both acute and low-level prolonged exposures develops peripheral neuropathy without preceding cholinergic toxicity and the progress of changes in EMG and NCV is parallel with the development of IMS and OPIDN. Persistent inhibition of acetylcholinesterase (AChE) is responsible for muscle weakness, but this is not the only factor involved in the incidence of this weakness in IMS or OPIDN suggestive of AChE assay not useful as an index of nerve and muscle impairment. Although several mechanisms for induction of this neurodegenerative disorder have been proposed as were reviewed for this article, among them oxidative stress and resulting apoptosis can be emphasized. Nevertheless, there is little synchronized evidence on subclinical electrophysiological findings that limit us to reach a strong conclusion on the diagnostic or prognostic use of EMG and NCV for acute and occupational exposures to OPs.
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Affiliation(s)
- S Karami-Mohajeri
- Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - S Nikfar
- Department of Pharmacoeconomics and Pharmaceutical Administration, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
- Food and Drug Laboratory Research Center, Food and Drug Organization, Tehran, Islamic Republic of Iran
| | - M Abdollahi
- Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
- Department of Pharmacoeconomics and Pharmaceutical Administration, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
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Ross SM, McManus IC, Harrison V, Mason O. Neurobehavioral problems following low-level exposure to organophosphate pesticides: a systematic and meta-analytic review. Crit Rev Toxicol 2012; 43:21-44. [DOI: 10.3109/10408444.2012.738645] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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18
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Blanc-Lapierre A, Bouvier G, Garrigou A, Canal-Raffin M, Raherison C, Brochard P, Baldi I. Effets chroniques des pesticides sur le système nerveux central : état des connaissances épidémiologiques. Rev Epidemiol Sante Publique 2012; 60:389-400. [DOI: 10.1016/j.respe.2012.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 02/23/2012] [Accepted: 03/26/2012] [Indexed: 12/14/2022] Open
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Starks SE, Gerr F, Kamel F, Lynch CF, Alavanja MC, Sandler DP, Hoppin JA. High pesticide exposure events and central nervous system function among pesticide applicators in the Agricultural Health Study. Int Arch Occup Environ Health 2011; 85:505-15. [PMID: 21927986 DOI: 10.1007/s00420-011-0694-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Accepted: 08/11/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE While acute pesticide poisoning can be associated with persistent adverse central nervous system (CNS) effects, little is known about the effect of one or more episodic and unusually high pesticide exposure events (HPEE) that typically do not result in acute poisoning. The objective of this investigation was to examine the association between ever having an HPEE and CNS function among licensed pesticide applicators enrolled in the Agricultural Health Study (AHS). METHODS In 2006-2008, 693 male participants with no history of a physician-diagnosed pesticide poisoning completed nine neurobehavioral tests to assess memory, motor speed, sustained attention, verbal learning, and visual scanning and processing. Information on ever having an HPEE and pesticide poisonings was obtained from previous AHS interviews. Associations between ever having an HPEE and neurobehavioral outcomes were estimated with linear regression controlling for age and outcome-specific covariates. RESULTS A history of ever having an HPEE was reported by 156 (23%) participants. Adverse associations were observed between ever having an HPEE and two of the nine neurobehavioral tests. On a test of visual scanning and processing (Digit-Symbol), participants who ever had an HPEE were 4.2 s slower (95% CI: -7.27, -1.11) than those without an HPEE, equivalent to the effect of 3.9 years of age in this population. On a test of visual scanning and motor speed (Sequences A), participants who ever had an HPEE were 2.5 s slower (95% CI: -4.53, -0.41) than those without an HPEE, equivalent to the effect of 3.9 years of age. No significant associations were observed between participants who ever had an HPEE and the remaining neurobehavioral tests. CONCLUSIONS One or more HPEE may contribute to adverse CNS outcomes independent of diagnosed pesticide poisoning.
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Affiliation(s)
- Sarah E Starks
- Department of Occupational and Environmental Health, University of Iowa, University of Iowa Research Park, 140 IREH, Iowa City, IA 52242-5000, USA
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Rohlman DS, Anger WK, Lein PJ. Correlating neurobehavioral performance with biomarkers of organophosphorous pesticide exposure. Neurotoxicology 2010; 32:268-76. [PMID: 21182866 DOI: 10.1016/j.neuro.2010.12.008] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/03/2010] [Accepted: 12/13/2010] [Indexed: 12/20/2022]
Abstract
There is compelling evidence that adverse neurobehavioral effects are associated with occupational organophosphorous pesticide (OP) exposure in humans. Behavioral studies of pesticide applicators, greenhouse workers, agricultural workers and farm residents exposed repeatedly over months or years to low levels of OPs reveal a relatively consistent pattern of neurobehavioral deficits. However, only two studies have demonstrated a link between neurobehavioral performance and current biomarkers of OP exposure including blood cholinesterase (ChE) activity and urinary levels of OP metabolites. A variety of reasons may explain why so few studies have reported such correlations, including differing individual and group exposure histories, differing methodologies for assessing behavior and exposure, and lack of a reliable index of exposure. Alternatively, these data may suggest that current biomarkers (ChE, urine metabolites) are neither predictive nor diagnostic of the neurobehavioral effects of chronic OP pesticide exposures. This review focuses on the evidence that neurobehavioral performance deficits are associated with occupational OP pesticide exposure and concludes that research needs to return to the basics and rigorously test the relationships between neurobehavioral performance and both current (ChE and urine metabolites) and novel (e.g., inflammation and oxidative stress) biomarkers using human and animal models. The results of such studies are critically important because OP pesticides are widely and extensively used throughout the world, including situations where exposure controls and personal protective equipment are not routinely used.
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Affiliation(s)
- Diane S Rohlman
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, OR 97239, USA.
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21
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Neuropsychological and psychiatric functioning in sheep farmers exposed to low levels of organophosphate pesticides. Neurotoxicol Teratol 2010; 32:452-9. [PMID: 20227490 DOI: 10.1016/j.ntt.2010.03.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 03/02/2010] [Accepted: 03/02/2010] [Indexed: 11/21/2022]
Abstract
The study aim was to determine whether low level exposure to organophosphate pesticides (OPs) causes neuropsychological or psychiatric impairment. Methodological weaknesses of earlier studies were addressed by: recruiting participants who had retired on ill health grounds; excluding participants with a history of acute poisoning, medical or psychiatric conditions that might account for ill health; and exploring factors which may render some individuals more vulnerable to the effects of OPs than others. Performance on tests of cognition and mood of 127 exposed sheep farmers (67 working, 60 retired) was compared with 78 unexposed controls (38 working, 40 retired) and published test norms derived from a cross section of several thousand adults in the general population. Over 40% of the exposed cohort reported clinically significant levels of anxiety and depression compared to less than 23% of controls. Exposed subjects performed significantly worse than controls and standardisation samples on tests of memory, response speed, fine motor control, mental flexibility and strategy making, even after controlling for the effects of mood. The pattern was similar for both working and retired groups. The cognitive deficits identified cannot be attributed to mood disorder, malingering, a history of acute exposure or genetic vulnerability in terms of PON1(192) polymorphisms. Results suggest a relationship may exist between low level exposure to organophosphates and impaired neurobehavioural functioning and these findings have implications for working practice and for other occupational groups exposed to OPs such as aviation workers and Gulf War veterans.
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McDonough JH. Performance Impacts of Nerve Agents and Their Pharmacological Countermeasures. MILITARY PSYCHOLOGY 2009. [DOI: 10.1207/s15327876mp1402_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- John H. McDonough
- Applied Pharmacology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
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London L. Neurobehavioural methods, effects and prevention: Workers’ human rights are why the field matters for developing countries. Neurotoxicology 2009; 30:1135-43. [DOI: 10.1016/j.neuro.2009.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 01/13/2009] [Indexed: 11/15/2022]
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Colosio C, Tiramani M, Brambilla G, Colombi A, Moretto A. Neurobehavioural effects of pesticides with special focus on organophosphorus compounds: which is the real size of the problem? Neurotoxicology 2009; 30:1155-61. [PMID: 19751763 DOI: 10.1016/j.neuro.2009.09.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 09/04/2009] [Accepted: 09/04/2009] [Indexed: 12/01/2022]
Abstract
The risk of neurobehavioural impairment as a consequence of a prolonged, low dose exposure to neurotoxic pesticides is not clearly demonstrated despite numerous publications addressing the topic. We reviewed the 24 papers published on human neurobehavioural effects of organophosphorus and/or carbamates pesticides up to May 1st 2008. Variables evaluated were compound/s addressed, number of subjects, approach to measure or estimate exposure, characteristics of control groups and presence of confounders, methodological approach, and type of alteration, taking into account cognitive, sensory-motor, psychological, and psychomotor measures. A total of 6 papers considered the whole spectrum of functions, the studies yielding positive or uncertain results were 13 (68%) for cognitive function, 11 (69%) for psychomotor function, 11 (65%) for sensory-motor function, and 11 (65%) for psychological function impairment. In 46% of the positive studies a previous severe acute poisoning was reported. Exposure levels were measured only in 5 studies, and very often there were problems in the selection of controls, and firm conclusions on the risk of neurobehavioural effects cannot be reached yet. The main limits of the available data are: limited number of studies and compounds addressed, significant differences in the approach among studies, poor concordance of the results of different studies, and difficulties in controlling confounding factors. Nevertheless, there are sufficient data to conclude that neurobehavioural impairment might be the consequence of an acute poisoning, and possibly the consequence of relatively high and prolonged exposures.
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Affiliation(s)
- C Colosio
- Department of Occupational and Environmental Health of the University of Milano, Italy.
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25
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Dassanayake T, Gawarammana IB, Weerasinghe V, Dissanayake PS, Pragaash S, Dawson A, Senanayake N. Auditory event-related potential changes in chronic occupational exposure to organophosphate pesticides. Clin Neurophysiol 2009; 120:1693-8. [PMID: 19683468 PMCID: PMC3145119 DOI: 10.1016/j.clinph.2009.07.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 07/06/2009] [Accepted: 07/14/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To determine whether chronic occupational exposure to organophosphates (OP) pesticides leads to cognitive impairment using event-related potentials (ERPs). METHODS ERPs of 38 vegetable farmers applying OP pesticides and 35 controls were recorded using an auditory oddball paradigm. The N1, P2, N2 and P300 ERP components and the number of counting errors were compared between the groups. RESULTS The farmers made significantly more counting errors than controls in the oddball task. The mixed model ANOVA of component latencies revealed a significant componentxgroup interaction, suggesting farmers had a greater delay in later ERP components. Intergroup comparisons of individual components showed significant delays in N2 and P300 latencies. Subsequent ANCOVA showed significant P300 delay even after adjusting for the latency of the preceding component, N2. Intergroup differences of P300 amplitudes were not significant, although there was limited evidence of a difference in scalp topography. CONCLUSION Our findings indicate that chronic low-level occupational exposure to OP pesticides is associated with progressively increasing delay in successive ERP components, particularly P300. SIGNIFICANCE Chronic exposure to OP pesticides may delay the neurophysiological processes underlying early stages of selective attention and late stages of sensory information processing that include stimulus evaluation and updating of working memory.
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Affiliation(s)
- T Dassanayake
- Department of Physiology, Faculty of Medicine, University of Peradeniya, Peradeniya 20400, Sri Lanka.
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Cox RD, Kolb JC, Galli RL, Carlton FR, Cook AM. Evaluation of Potential Adverse Health Effects Resulting from Chronic Domestic Exposure to the Organophosphate Insecticide Methyl Parathion. Clin Toxicol (Phila) 2008. [DOI: 10.1081/clt-58952] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abstract
Several pesticides such as organophosphates, carbamates and the organochlorine pesticides directly target nervous tissue as their mechanism of toxicity. In several others, such as the fumigants, the nervous system is affected by toxicological mechanisms that diffusely affect most or all tissues in the body. Both the central and peripheral nervous system are involved in the acute toxidromes of many pesticides resulting in acute short-term effects. There is strong human epidemiological evidence for persistent nervous system damage following acute intoxication with several important pesticide groups such as organophosphates and certain fumigants. However, whether persistent nervous system damage follows chronic low-level exposure to pesticides in adults (particularly organophosphpates), and whether in utero and/or early childhood exposure leads to persistent nervous system damage, is a subject of study at present. Parkinson's Disease, one of the most common chronic central nervous system diseases, has been linked to pesticide exposure in some studies, but other studies have failed to find an association. Several new pesticidal chemicals such as the neo-nicotinoids and fipronil have central nervous system effects, but only case reports are available to date on acute human intoxications with several of these. Little data are yet available on whether long-term effects result from these chemicals. Several ongoing or recently completed studies should add valuable insight into the effects of pesticides on the human nervous system particularly the effect of low-dose, chronic exposure both in adults and children.
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Lizardi PS, O'Rourke MK, Morris RJ. The effects of organophosphate pesticide exposure on Hispanic children's cognitive and behavioral functioning. J Pediatr Psychol 2007; 33:91-101. [PMID: 17569709 DOI: 10.1093/jpepsy/jsm047] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE This study investigates the effects of Organophosphate (OP) pesticides exposure on the cognitive and behavioral functioning of Hispanic children living in an agricultural community. METHODS Forty-eight children were administered a battery of cognitive measures, and their parents and teachers completed behavior rating scales. Children provided a urine sample for analysis of OP pesticides metabolites. RESULTS All children had a detectable level of at least one OP pesticide metabolite. Higher OP pesticide metabolite concentration levels were significantly correlated with poorer performance on some subtests of the Wisconsin Card Sorting Test. However, the significance of this association was dependent upon the inclusion of two samples with noticeable higher OP pesticide metabolite concentration levels. CONCLUSIONS Short-term OP pesticide exposure seems to have deleterious effects on children's speed of attention, sequencing, mental flexibility, visual search, concept formation, and conceptual flexibility. This study is among a relatively small number of studies investigating an extremely complex problem. Limitations and suggestions for future studies are discussed.
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Affiliation(s)
- Patricia Sánchez Lizardi
- Pupil Services and Special Education, Chula Vista Elementary School District, 84 E J Street, Chula Vista, CA 91910, USA.
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Kamel F, Engel LS, Gladen BC, Hoppin JA, Alavanja MCR, Sandler DP. Neurologic symptoms in licensed pesticide applicators in the Agricultural Health Study. Hum Exp Toxicol 2007; 26:243-50. [PMID: 17439927 DOI: 10.1177/0960327107070582] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate pesticide levels. We analysed cross-sectional data from 18 782 Caucasian, male, licensed pesticide applicators, enrolled in the Agricultural Health Study from 1993 to 1997. Applicators provided information on lifetime pesticide use, and 23 neurologic symptoms typically associated with pesticide intoxication. Increased risk of experiencing >/=10 symptoms during the year before enrollment was associated with cumulative pesticide use, personally mixing or applying pesticides, pesticide-related medical care, diagnosed pesticide poisoning, and events involving high personal pesticide exposure. Greatest risk was associated with use of organophosphate and organochlorine insecticides. Results were similar after stratification by pesticide use during the year before enrollment, or exclusion of applicators with a history of pesticide poisoning, or high-exposure events. Use of pesticide application methods likely to involve high personal exposure was associated with greater risk. Groups of symptoms reflecting several neurologic domains, including affect, cognition, autonomic and motor function, and vision, were also associated with pesticide exposure. These results suggest that neurologic symptoms are associated with cumulative exposure to moderate levels of organophosphate and organochlorine insecticides, regardless of recent exposure or history of poisoning.
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Affiliation(s)
- F Kamel
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, PO Box 12233, Research Triangle Park, NC 27709, USA.
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de Araújo AJ, de Lima JS, Moreira JC, Jacob SDC, Soares MDO, Monteiro MCM, do Amaral AM, Kubota A, Meyer A, Cosenza CAN, das Neves C, Markowitz S. Exposição múltipla a agrotóxicos e efeitos à saúde: estudo transversal em amostra de 102 trabalhadores rurais, Nova Friburgo, RJ. CIENCIA & SAUDE COLETIVA 2007; 12:115-30. [PMID: 17680063 DOI: 10.1590/s1413-81232007000100015] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 08/30/2006] [Indexed: 11/22/2022] Open
Abstract
Um estudo transversal foi realizado em uma comunidade agrícola localizada em Nova Friburgo, RJ, para conhecer os aspectos epidemiológicos, clínicos e laboratoriais da exposição múltipla a agrotóxicos em uma amostra representativa de 102 pequenos agricultores, de ambos os sexos. Os trabalhadores foram submetidos a um extenso protocolo que incluía aplicação de questionário ocupacional, coleta de amostras biológicas para exame toxicológico e avaliação clínica - geral e neurológica. Os resultados dos exames toxicológicos revelaram episódios leves a moderados de intoxicação aguda aos organofosforados descritos pelos agricultores ou observados durante o exame clínico. Foram também diagnosticados 13 (12,8 %) quadros de neuropatia tardia e 29 (28,5%) quadros de síndrome neurocomportamental e distúrbios neuropsiquiátricos associados ao uso crônico de agrotóxicos. Os resultados apontam para a ocorrência de episódios recorrentes de sobre-exposição múltipla, a elevadas concentrações de diversos produtos químicos, com grave prejuízo para as funções vitais desses trabalhadores, especialmente por se encontrarem em uma faixa etária jovem (média = 35 ± 11anos) e período produtivo da vida. Estes dados demonstram a importância do monitoramento da múltipla exposição a agrotóxicos, uma cadeia de eventos de grande repercussão na saúde pública e para o meio ambiente.
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Affiliation(s)
- Alberto José de Araújo
- NETT IDT HUCFF, Universidade Federal do Rio de Janeiro, Ilha do Fundão. 21941-913. Rio de Janeiro.
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Beseler C, Stallones L, Hoppin JA, Alavanja MCR, Blair A, Keefe T, Kamel F. Depression and pesticide exposures in female spouses of licensed pesticide applicators in the agricultural health study cohort. J Occup Environ Med 2007; 48:1005-13. [PMID: 17033500 PMCID: PMC1626656 DOI: 10.1097/01.jom.0000235938.70212.dd] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This nested case-control study evaluated the association between depression and pesticide exposure among women. METHODS The study population included 29,074 female spouses of private pesticide applicators enrolled in the Agricultural Health Study between 1993 and 1997. Cases were women who had physician-diagnosed depression requiring medication. Lifetime pesticide use was categorized as never mixed/applied pesticides, low exposure (up to 225 days), high exposure (>225 days), and a history of diagnosed pesticide poisoning. RESULTS After adjustment for state, age, race, off-farm work, alcohol, cigarette smoking, physician visits, and solvent exposure, depression was significantly associated with a history of pesticide poisoning (odds ratio [OR] = 3.26; 95% confidence interval [CI] = 1.72-6.19) but not low (OR = 1.09; CI = 0.91-1.31) or high (OR = 1.09; 95% CI = 0.91-1.31) cumulative pesticide exposure. CONCLUSION Pesticide poisoning may contribute to risk of depression.
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Affiliation(s)
- Cheryl Beseler
- Colorado Injury Control Research Center, Department of Psychology, Colorado State University, Fort Collins, Colorado 80523, USA. cbeseler@lamar,colostate.edu
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Testud F, Grillet JP. Insecticides organophosphorés, carbamates, pyréthrinoïdes de synthèse et divers. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1155-1925(07)71836-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Claus Henn B, McMaster S, Padilla S. Measuring cholinesterase activity in human saliva. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2006; 69:1805-18. [PMID: 16905510 DOI: 10.1080/15287390600631458] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
To assess the potential for using saliva in pesticide biomonitoring, the consistency of cholinesterase activity in human saliva collected over time was examined. In this pilot study, saliva was collected from 20 healthy adults once per week for 5 consecutive weeks using 2 different collection methods: a disposable plastic pipette, and a cotton-wool roll. A brief questionnaire was conducted each week to document changes in exposure to cholinesterase inhibitors for the duration of the sampling. To measure cholinesterase activity, an existing radiometric method was modified to make it suitable for human saliva. Using this method, cholinesterase activity was measurable in saliva, and duplicate samples showed reliable repeatability. Activity in both collection methods ranged from 3 to 265 nmol/h/ml saliva (mean = 52 +/- 37 [SD] nmol/h/ml saliva). For some individuals, enzyme activity was consistent over the five sampling weeks; for others, activity was highly variable. Coefficients of variation (CVs) were calculated to assess variability, and mean CVs were the same for both collection methods (about 35%). Adjusting for protein concentration in the pipette-collected samples did not change results. Both collection methods worked well for collecting between 1 and 3 ml saliva, but at the majority of visits (86%), participants preferred the cotton-wool roll. Results from this study suggest that saliva may be a useful indicator of potential neurotoxic effects from exposure to organophosphorus and carbamate pesticides, but that factors affecting variability should be explored further.
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Affiliation(s)
- Birgit Claus Henn
- U.S. Environmental Protection Agency, Neurotoxicology Division and Human Studies Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, Research Triangle Park, North Carolina 27711, USA
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Stephens R, Sreenivasan B. Neuropsychological effects of long-term low-level organophosphate exposure in orchard sprayers in England. ACTA ACUST UNITED AC 2006; 59:566-74. [PMID: 16599004 DOI: 10.1080/00039890409603435] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The health effects from prolonged low-level organophosphate exposure are unknown. We hypothesized that exposed individuals would show neuropsychological decrements when compared with unexposed individuals, and that cumulative organophosphate exposure would be correlated with neuropsychological performance. We used a quasiexperimental cross-sectional design to compare neuropsychological test scores among three groups: orchard sprayers exposed to organophosphates, and construction worker and pig farm workers who were not exposed. Relative to construction workers, orchard sprayers were significantly slower on negative statements of the syntactic reasoning test. However, we found no relationship between cumulative exposure and test response. The slower response of the orchard sprayers was apparently exposure-related, but we could not identify an underlying neurotoxic mechanism. Therefore, we are unable to conclude whether this is a specific cognitive effect, or a decrement arising on the most sensitive test employed.
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Affiliation(s)
- Richard Stephens
- School of Psychology, Keele University, Staffordshire ST5 5BG, UK.
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Kamel F, Engel LS, Gladen BC, Hoppin JA, Alavanja MCR, Sandler DP. Neurologic symptoms in licensed private pesticide applicators in the agricultural health study. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:877-82. [PMID: 16002376 PMCID: PMC1257649 DOI: 10.1289/ehp.7645] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Exposure to high levels of many pesticides has both acute and long-term neurologic consequences, but little is known about the neurotoxicity of chronic exposure to moderate levels of pesticides. We analyzed cross-sectional data from 18,782 white male licensed private pesticide applicators enrolled in the Agricultural Health Study in 1993-1997. Applicators provided information on lifetime pesticide use and 23 neurologic symptoms typically associated with pesticide intoxication. An indicator of more symptoms (> or = 10 vs. < 10) during the year before enrollment was associated with cumulative lifetime days of insecticide use: odds ratios (95% confidence intervals) were 1.64 (1.36-1.97) for 1-50 days, 1.89 (1.58-2.25) for 51-500 days, and 2.50 (2.00-3.13) for > 500 days, compared with never users. A modest association for fumigants [> 50 days, 1.50 (1.24-1.81)] and weaker relationships for herbicides [> 500 days, 1.32 (0.99-1.75)] and fungicides [> 50 days, 1.23 (1.00-1.50)] were observed. Pesticide use within the year before enrollment was not associated with symptom count. Only associations with insecticides and fumigants persisted when all four pesticide groups were examined simultaneously. Among chemical classes of insecticides, associations were strongest for organophosphates and organochlorines. Associations with cumulative exposure persisted after excluding individuals who had a history of pesticide poisoning or had experienced an event involving high personal pesticide exposure. These results suggest that self-reported neurologic symptoms are associated with cumulative exposure to moderate levels of fumigants and organophosphate and organochlorine insecticides, regardless of recent exposure or history of poisoning.
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Affiliation(s)
- Freya Kamel
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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37
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Pires DX, Caldas ED, Recena MCP. Intoxicações provocadas por agrotóxicos de uso agrícola na microrregião de Dourados, Mato Grosso do Sul, Brasil, no período de 1992 a 2002. CAD SAUDE PUBLICA 2005; 21:804-14. [PMID: 15868038 DOI: 10.1590/s0102-311x2005000300014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As notificações de intoxicações e tentativas de suicídio provocadas por agrotóxicos na microrregião de Dourados, Mato Grosso do Sul, entre 1992 e 2002, foram avaliadas baseando-se nos registros do Centro Integrado de Vigilância Toxicológica da Secretaria de Saúde do estado. Foram notificadas 475 ocorrências no período, sendo 261 intoxicações (acidental ou ocupacional), 203 tentativas de suicídio e 11 eventos de causa indeterminada. O Município de Dourados apresentou a maior prevalência de intoxicações, por 100 mil habitantes, considerando a população rural, e Fátima do Sul a segunda maior prevalência de suicídios na microrregião. Correlações significativas foram encontradas entre intoxicação e tentativa de suicídio (r = 0,60; p < 0,05), e entre intoxicação e razão entre a área ocupada por culturas temporárias e área total do município (r = 0,68; p < 0,05). As intoxicações ocorreram predominantemente com homens (87,0%), mas a diferença entre tentativas de suicídio em homens e mulheres não foi acentuada (53,0 e 47,0%, respectivamente). Os eventos ocorreram principalmente entre outubro e março, e os inseticidas organofosforados monocrotofós e metamidofós foram os principais agrotóxicos envolvidos.
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Affiliation(s)
- Dario Xavier Pires
- Departamento de Química, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brazil.
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38
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Abstract
Effective brain function is dependent on precise and complex interactions among neurotransmitters, hormones, enzymes, and electrolytes. Many of the chemically complex substances with which we come into contact can disrupt this intricately balanced system. Toxic substances, whether ingested, inhaled, or absorbed through the skin, may cause an encephalopathic state directly by affecting the brain itself or indirectly by compromising the brain's supportive systems. The article focuses on neurotoxins (heavy metals, solvents and vapors, pesticides, and natural neurotoxins) that directly induce an encephalopathic state.
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Affiliation(s)
- Tracy Eicher
- Wilford Hall Medical Center, Lackland Air Force Base, 2200 Bergquist Drive, Suite 1/MMCN, TX 78236, USA
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39
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Kimura K, Yokoyama K, Sato H, Nordin RB, Naing L, Kimura S, Okabe S, Maeno T, Kobayashi Y, Kitamura F, Araki S. Effects of pesticides on the peripheral and central nervous system in tobacco farmers in Malaysia: studies on peripheral nerve conduction, brain-evoked potentials and computerized posturography. INDUSTRIAL HEALTH 2005; 43:285-94. [PMID: 15895843 DOI: 10.2486/indhealth.43.285] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We examined the effects of pesticides on the central and peripheral nervous system in the setting of a tobacco farm at a developing country. Maximal motor and sensory nerve conduction velocities (MCV and SCV, respectively) in the median, sural and tibial nerves, postural sway, and brain-evoked potentials (auditory event-related and visual-evoked potentials) were measured in 80 male tobacco farmers and age- and sex-matched 40 controls in Kelantan, Malaysia. Median SCV (finger-wrist) in farmers using Delsen (mancozeb, dithiocarbamate fungicide), who showed significant decrease of serum cholinesterase activities, were significantly lower compared with the controls. Sural SCV in farmers using Fastac (alpha-cypermethrin, pyrethroid insecticide) and median MCV (elbow-wrist) in farmers using Tamex (butralin, dinitroaniline herbicide) were significantly slowed compared with their respective controls. In Delsen (mancozeb, dithiocarbamate) users, the power of postural sway of 0-1 Hz was significantly larger than that in the controls both in the anterior-posterior direction with eyes open and in the right-left direction with eyes closed. The former type of sway was also significantly increased in Tamaron (methamidophos, organophosphorus insecticide) users. In conclusion, nerve conduction velocities and postural sway seem to be sensitive indicators of the effects of pesticides on the central and peripheral nervous system.
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Affiliation(s)
- Kaoru Kimura
- Department of Public Health, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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Woodward KN. Veterinary pharmacovigilance. Part 4. Adverse reactions in humans to veterinary medicinal products. J Vet Pharmacol Ther 2005; 28:185-201. [PMID: 15842307 DOI: 10.1111/j.1365-2885.2005.00648.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although seemingly rare, adverse reactions to veterinary products do occur. These may arise from inadvertent exposure during use or as a result of occupational accidents. They are often mild in nature and include adverse effects such as minor skin reactions. However, more serious reactions may occur, and they are not restricted to the effects of the veterinary medicines themselves. For example, high-pressure injection injuries may occur as a result of accidents occurring during animal vaccination operations. This paper reviews some of these events, mentions where appropriate the regulatory actions taken, and describes some of the measures used to minimise such effects in the future, and serves to bring the issues discussed here to the attention of pharmacologists, pharmacoepidemiologists and others who train those who use veterinary medicinal products.
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Affiliation(s)
- K N Woodward
- Schering-Plough Animal Health, Uxbridge, Middlesex, UK.
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41
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London L, Flisher AJ, Wesseling C, Mergler D, Kromhout H. Suicide and exposure to organophosphate insecticides: cause or effect? Am J Ind Med 2005; 47:308-21. [PMID: 15776467 DOI: 10.1002/ajim.20147] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Suicide using pesticides as agent is recognized as a major cause of pesticide poisoning. METHODS A literature review of mortality and morbidity studies related to suicide among pesticide-exposed populations, and of human and animal studies of central nervous system toxicity related to organophosphate (OP) pesticides was performed. RESULTS Suicide rates are high in farming populations. Animal studies link OP exposure to serotonin disturbances in the central nervous system, which are implicated in depression and suicide in humans. Epidemiological studies conclude that acute and chronic OP exposure is associated with affective disorders. Case series and ecological studies also support a causal association between OP use and suicide. CONCLUSIONS OPs are not only agents for suicide. They may be part of the causal pathway. Emphasizing OPs solely as agents for suicide shifts responsibility for prevention to the individual, reducing corporate responsibility and limiting policy options available for control.
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Affiliation(s)
- L London
- Occupational and Environmental Health Research Unit, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa.
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Kamel F, Hoppin JA. Association of pesticide exposure with neurologic dysfunction and disease. ENVIRONMENTAL HEALTH PERSPECTIVES 2004; 112:950-8. [PMID: 15198914 PMCID: PMC1247187 DOI: 10.1289/ehp.7135] [Citation(s) in RCA: 337] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Accepted: 05/19/2004] [Indexed: 05/19/2023]
Abstract
Poisoning by acute high-level exposure to certain pesticides has well-known neurotoxic effects, but whether chronic exposure to moderate levels of pesticides is also neurotoxic is more controversial. Most studies of moderate pesticide exposure have found increased prevalence of neurologic symptoms and changes in neurobehavioral performance, reflecting cognitive and psychomotor dysfunction. There is less evidence that moderate exposure is related to deficits in sensory or motor function or peripheral nerve conduction, but fewer studies have considered these outcomes. It is possible that the most sensitive manifestation of pesticide neurotoxicity is a general malaise lacking in specificity and related to mild cognitive dysfunction, similar to that described for Gulf War syndrome. Most studies have focused on organophosphate insecticides, but some found neurotoxic effects from other pesticides, including fungicides, fumigants, and organochlorine and carbamate insecticides. Pesticide exposure may also be associated with increased risk of Parkinson disease; several classes of pesticides, including insecticides, herbicides, and fungicides, have been implicated. Studies of other neurodegenerative diseases are limited and inconclusive. Future studies will need to improve assessment of pesticide exposure in individuals and consider the role of genetic susceptibility. More studies of pesticides other than organophosphates are needed. Major unresolved issues include the relative importance of acute and chronic exposure, the effect of moderate exposure in the absence of poisoning, and the relationship of pesticide-related neurotoxicity to neurodegenerative disease.
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Affiliation(s)
- Freya Kamel
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA.
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Abstract
Pesticides are widely used in agricultural and other settings, resulting in continuing human exposure. Epidemiologic studies indicate that, despite premarket animal testing, current exposures are associated with risks to human health. In this review, we describe the routes of pesticide exposures occurring today, and summarize and evaluate the epidemiologic studies of pesticide-related carcinogenicity and neurotoxicity in adults. Better understanding of the patterns of exposure, the underlying variability within the human population, and the links between the animal toxicology data and human health effects will improve the evaluation of the risks to human health posed by pesticides. Improving epidemiology studies and integrating this information with toxicology data will allow the human health risks of pesticide exposure to be more accurately judged by public health policy makers.
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Affiliation(s)
- Michael C R Alavanja
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Blvd., Rockville, Maryland 20892, USA.
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Albers JW, Garabrant DH, Schweitzer S, Garrison RP, Richardson RJ, Berent S. Absence of sensory neuropathy among workers with occupational exposure to chlorpyrifos. Muscle Nerve 2004; 29:677-86. [PMID: 15116371 DOI: 10.1002/mus.20007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Several studies have reported the occurrence of sensory neuropathy with exposure to chlorpyrifos and other organophosphorus insecticides, at levels not associated with overt toxicity. We evaluated 113 chemical workers, including 53 of 66 (80%) eligible chlorpyrifos workers and 60 of 74 (81%) randomly selected referent workers, to identify evidence of sensory neuropathy or subclinical neuropathy. Compared to referents, chlorpyrifos subjects had significantly longer duration of work in chlorpyrifos-exposed areas (9.72 vs. 0.01 years; P < 0.0001), greater cumulative chlorpyrifos exposure (64.16 vs. 0.69 mg/m(3). day; P < 0.0001), higher urine 3,5,6-trichloro-2-pyridinol (TCP) excretion (108.6 vs. 4.3 microg/g creatinine; P < 0.0001), and lower plasma butyrylcholinesterase (BuChE) activity (7281 vs. 8176 mU/ml; P = 0.003). Despite exposures among chlorpyrifos subjects to levels at which well-described physiological effects on B-esterases exist, the frequency of symptoms or signs of neuropathy did not differ significantly between groups, and the only 2 subjects fulfilling criteria for confirmed neuropathy were both in the referent group. Mean nerve conduction study results were comparable to established control values and did not differ significantly between groups. We found no evidence of sensory neuropathy or isolated peripheral abnormalities among subjects with long-term chlorpyrifos exposure at levels known to be associated with the manufacturing process.
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Affiliation(s)
- James W Albers
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
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Abstract
The authors have reviewed the literature on neurobehavioral toxicity of pesticides to assess the status of knowledge on this matter. Some data suggest that exposure to DDT and fumigants may be associated with permanent decline in neurobehavioral functioning and increase in psychiatric symptoms, but, due to the limited number of studies available and the scarce knowledge on exposure levels, no firm conclusion can be drawn. Data on subjects acutely poisoned with organophosphorous compounds suggest that an impairment in neurobehavioral performance and, in some cases, emotional status may be observed as a long-term sequela, but the possibility still remains that these effects were only an aspecific expression of damage and not of direct neurotoxicity. Studies carried out on subjects chronically exposed to organophosphates, but never acutely poisoned, do not provide univocal results but the slight changes consistently observed in sheep dippers suggest the need of focusing on activities characterized by relatively higher exposure levels. In general, the main limits of existing knowledge are the variability of the testing methods used, which makes it difficult to compare the results of single studies, and the scarce knowledge on exposure levels. A promising approach may be the conduction of prospective longitudinal or cohort studies, where exposure and dose assessment can be more easily controlled, or the evaluation of cohorts of workers a priori selected for the availability of environmental and biological monitoring data. The follow up of the populations under study may give an answer at the problem of the prognostic significance of the observed changes. Also the protocols used to assess neurobehavioral functioning need to be standardized.
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Affiliation(s)
- C Colosio
- International Centre for Pesticides and Health Risk Prevention, Via Magenta 25, 20020 Busto Garolfo, Milan, Italy.
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46
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Abstract
Some studies have suggested a role of pesticide exposure in the development of neurobehavioral disorders. This case-control study examined the association between mortality from mental disorders and occupational exposure to pesticides. The study population consisted of 7756 deaths and 330,452 eligible controls identified from US death certificate files for the years 1988 through 1992. Exposure assignment was based on job title reported on the death certificates. Employment in jobs potentially involving pesticide exposure was weakly associated with the risk of death from mental disorders (odds ratio [OR] = 1.46; 95% confidence interval (95% CI) = 1.33-1.60). This association was stronger among women (OR = 2.65; 95% CI = 1.89-3.71), in particular for deaths from neurotic disorders (OR = 4.32; 95% CI = 2.44-7.64). These results must be interpreted with caution, however, because the impact of social and work-related factors other than pesticide exposure is not known.
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Jamal GA, Hansen S, Julu POO. Low level exposures to organophosphorus esters may cause neurotoxicity. Toxicology 2002; 181-182:23-33. [PMID: 12505280 DOI: 10.1016/s0300-483x(02)00447-x] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A large number of published studies support the notion that long term, low level (LTLL) exposure to organophosphorus (OP) esters may cause neurological and neurobehavioral effects. In order to differentiate these from other effects of OP such as the acute cholinergic episodes, intermediate syndrome and organophosphate induced delayed neuropathy (OPIDN), the term Chronic Organophosphate Induced Neuropsychiatric Disorder (COPIND) will be used purely for the ease of reference. The question addressed in this particular review is whether LTLL exposure to OP may produce neurotoxicity. The profile and the degree of overlap of the various components of COPIND have been addressed elsewhere and description of the possible mechanisms for COPIND is outside the scope of this article. COPIND can be classified under two headings; those produced following one or more acute clinical cholinergic episodes, and those produced without such preceding attacks. With regards to the first group, there are a total of 11 studies, all of which support the existence of a positive link between exposure to OP and neurotoxicity; six of these studies comprise descriptions of large numbers of cases without controls while five additional studies employ controls. Appearance of neurotoxicity does not seem to be related to the number or the intensity of acute cholinergic attacks. With regards to the second group, three types of studies can be identified. Firstly, there are five studies using experimental animals, all of which showed a positive link between OP and neurotoxicity. Secondly, a total of seven case studies without controls, some involving large numbers of patients, concluded that there is a positive link between OP and neurotoxicity. Thirdly, 19 studies investigated such a link using cases and control groups. Of these, 15 studies (about 80%) showed a positive link and only four failed to identify any link between OP and neurotoxicity. Annotation of all the 19 studies according to ideal set of criteria showed that only a few of these comply with the rules of excellence and all of these few showed a positive link. Furthermore, the only study carried out blind without the identification of subjects or controls, showed a positive link between OP and neurotoxicity. This blind study estimated the overall incidence of a form of neurotoxicity in people exposed to OP to be about 40 times higher than in the general population. The type of neurological involvement was unique and different from OP induced syndromes previously described. The profile of the neurological involvement was similar to that in COPIND whether or not preceded by acute cholinergic episodes, thus providing further evidence that these two neuropathies probably share a similar mechanism. There is a characteristic pattern of involvement of 15 functional indices of the autonomic nervous system examined in our laboratory. There are, in addition, preferential anatomical sites of target organs affected, selective preservation of cholinergic function within the same neuropathy-positive site, and evidence of mal-function of cardiac chemoreceptors in patients exposed to OP. The peripheral nerve involvement in OP exposure is predominantly sensory in nature affecting both small and large fibre populations. Neurobehavioral involvement of mainly cognitive dysfunction and other features are also described in other studies. The weight of current evidence is therefore very much in favor of the motion that chronic low-level exposure to OP produces neurotoxicity. Criticisms levelled against this motion are unfounded and probably misconceived.
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Affiliation(s)
- Goran A Jamal
- Division of Neurosciences, Imperial College of Science, Technology and Medicine, University of London, London, UK.
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Jamal GA, Hansen S, Pilkington A, Buchanan D, Gillham RA, Abdel-Azis M, Julu POO, Al-Rawas SF, Hurley F, Ballantyne JP. A clinical neurological, neurophysiological, and neuropsychological study of sheep farmers and dippers exposed to organophosphate pesticides. Occup Environ Med 2002; 59:434-41. [PMID: 12107290 PMCID: PMC1740317 DOI: 10.1136/oem.59.7.434] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To classify clinical diseases of the subjects with abnormal indices of peripheral neuropathy identified in field studies of sheep farmers and dippers exposed to organophosphate pesticides. To explore what neuropsychological profiles, if any, may be associated with neurophysiological damage in these subjects. METHODS A case-control study (79 subjects) nested within the cross sectional study (685 subjects) of sheep farmers from the field study. Three groups with no, possible, and probable or definite neuropathy according to field studies were recruited. Investigations comprised symptoms of neuropathy, neurologial signs, motor and sensory nerve conduction, electromyography, quantitative sensory testing, and neuropsychological tests. RESULTS The incidence of clinical neuropathy increased from 7% in the no neuropathy group to 52% in the probable or definite neuropathy group based on nerve conduction measurements or presence of neurological signs. Sensory abnormalities were found more often than motor deficits. Small diameter nerve fibres were also affected more than large fibres. CONCLUSIONS The neuropathy is predominantly sensory and is characteristic of distal, chronic neuropathy with no acute features. Small fibre populations are affected more than large fibre populations. Increasing severity of neuropathy was associated with anxiety and depression as measured in the neuropsychological tests.
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Affiliation(s)
- G A Jamal
- Imperial College School of Medicine, London, UK
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49
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Pilkington A, Buchanan D, Jamal GA, Gillham R, Hansen S, Kidd M, Hurley JF, Soutar CA. An epidemiological study of the relations between exposure to organophosphate pesticides and indices of chronic peripheral neuropathy and neuropsychological abnormalities in sheep farmers and dippers. Occup Environ Med 2001; 58:702-10. [PMID: 11600725 PMCID: PMC1740069 DOI: 10.1136/oem.58.11.702] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To investigate the hypothesis that chronic low level exposure to organophosphates (OPs) in sheep dips is related to clinically detectable measures of polyneuropathy. METHODS The design was a cross sectional exposure-response study of sheep dippers and other non-exposed groups. The study group consisted of 612 sheep dipping farmers, 53 farmers with no sheep dipping experience, and 107 ceramics workers. Retrospective exposure information was obtained by questionnaire based on stable and easily identifiable features of sheep dipping found during the first phase of the study; in particular, estimates of handling concentrate and splashing with dilute dip. Neurological assessments were based on a standard neuropathy symptoms questionnaire, and thermal and vibration quantitative sensory tests. RESULTS Adjusted for confounders there was a weak positive association between cumulative exposure to OPs and neurological symptoms, the significance of which was dependent on the inclusion of a few individual workers with extremely high exposure. There was no evidence of an association between cumulative exposure and the thermal or vibration sensory thresholds. However, separating the effects of exposure intensity and duration showed a higher prevalence of symptoms, primarily of a sensory type, among sheep dippers who handled the OP concentrate. There was also evidence that sensory and vibration thresholds were higher among concentrate handlers, the highest exposed group of dippers. CONCLUSIONS The findings showed a strong association between exposure to OP concentrate and neurological symptoms, but a less consistent association with sensory thresholds. There was only weak evidence of a chronic effect of low dose cumulative exposure to OPs. It is suggested that long term health effects may occur in at least some sheep dippers exposed to OPs over a working life, although the mechanisms are unclear.
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Affiliation(s)
- A Pilkington
- Institute of Occupational Medicine, 8 Roxburgh Place, Edinburgh EH8 9SU, UK
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50
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Faria NM, Facchini LA, Fassa AG, Tomasi E. [The rural labor process and health in the Southern Brazilian mountains: a descriptive study]. CAD SAUDE PUBLICA 2000; 16:115-28. [PMID: 10738156 DOI: 10.1590/s0102-311x2000000100012] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This cross-sectional study among rural workers in the mountainous region of the southernmost Brazilian State of Rio Grande do Sul was designed to identify the characteristics of work performed on family farms. The research focused on the socio-demographic profiles of rural workers, identifying the characteristics of rural labor and describing the prevalence of some disease entities in such populations. Some 1479 rural workers from 495 farms were interviewed. In this sample, 87% of the individuals were members of the farm-owning family, mean age was 41 years, 56% were males, and mean schooling was 5 years. Farms had a mean area of 37 hectares, 50% had at least one type of farm machinery, and fruits constituted the main crop. About 75% of workers handled several types of pesticides, while 12% reported at least one lifetime episode of pesticide poisoning. Prevalence of minor psychiatric disorders was 36%, and annual frequency of occupational injuries was 10%. There was a wide variety of activities and occupational risks. The high prevalence of health problems identified in the study calls attention to the need for measures to promote and protect rural workers' health.
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Affiliation(s)
- N M Faria
- Núcleo de Saúde do Trabalhador, Departamento de Medicina Social, Universidade Federal de Pelotas, Pelotas, RS 96030-000, Brasil.
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