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[Tijuana] Neuropsychiatric Disorders in Farmers Associated with Organophosphorus Pesticide Exposure in a Rural Village of Northwest Mexico
México (AMMEF) - Universidad Autónoma de Baja California, Tijuana
Departamento de Neurociencias, Facultad de Medicina y Psicología, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, Tijuana 22300, México.
Aracely Serrano Medina
Aracely Serrano Medina
Type of Research Project
- Clinical Project with Laboratory work
What is the background of the project?
Exposure to organophosphates (OPs), such as nerve agents and pesticides, results in an irreversible inhibition of acetylcholinesterase (AChE) in neuromuscular junctions, peripheral and central neuronal synapses and in circulating red blood cells. Inhibition of AChE, which catalyzes the hydrolysis of the acetylcholine (ACh) neurotransmitter, results in increased levels of synaptic ACh and subsequent overstimulation of nicotinic and muscarinic ACh receptors. Cholinergic toxicity is clinically manifested by decreased heart and respiration rates, increased secretions, muscle tremors, paralysis, and death. The state of Baja California, Mexico, constitutes a pole of attraction for population from the rest of the country, partly due to its dynamics economic and geographical location close to the United States market. Agricultural activities are intensive in the Mexicali and San Quintin Valleys, with high market value. Intensive agricultural activities require the use of pesticides that are, undeniably, highly toxic, absorbable, and persistent, representing a health risk to farm workers. The use of OP pesticides in the northwest of the country favors products that contain insecticides, such as malathion, dicofol, methyl parathion, chlorpyrifos, phosmet, azinphos-methyl, and methamidophos. San Quintín, being the agricultural center of the state which still uses organophosphates as pesticides, represents a hot point for public health and for the working community of that sector; Therefore, the determination of the effects of organophosphates on the agricultural population, will give bases to raise awareness in the industry of the need to reduce or modify the use of these pesticides to protect the worker from its adverse effects, in addition, to reduce the economic burden that It represents for the health system to address these effects.
What is the aim of the project?
Determine by Worek's modified Ellman test the degree of inhibition of acetylcholinesterase in the central nervous system, as well as its psychiatric effects on agricultural workers by exposure to organophosphates present in the pesticides.
What techniques and methods are used?
The project has two stages of data collection and one of analysis of the data collected. The data collection stage is divided into two phases, the first one evaluates the neuropsychiatric status of the patients and the second stage which determines the activity of AChE: • For the data from the first phase, the ¨Mini International Neuropsychiatric Diagnostic Test ¨ (MINI) was used to assess their mental health status in both study groups. The test was applied under the same conditions to both groups. • For the second phase, to determine the activity of AChE, venous blood samples were collected in tubes with anticoagulant K2EDTA (3 ml per patient) to both study groups, using the Vacutainer system. The anticoagulated blood is separated into plasma and the globular pack by centrifugation for 10 minutes at 3000 RPM. Red blood cell samples were washed 3 times in cold isotonic saline (0.9%, v/w) and then hemolyzed by centrifuging for 10 min at 14,000 rpm. The AChE determination in the washed samples was performed immediately with the Worek method (modified Ellman colorimetric assay). For the data analysis stage, SPSS software package 21.0 (Chicago,USA) was used for all statistical evaluations. Comparisons between groups were analysed using the Student’s t-test, Chi-square test, and ANOVA, depending upon the distribution of variables. Correlation analysis was performed with the Spearman correlation test. Binary logistic regression analysis was undertaken for the evaluation of different variables on suicide risk. Statistical significance was accepted as p < 0.05.
What is the role of the student?
- The student will mainly observe
- The student will observe the practical experiments but will be highly involved in the analysis of the results
- The tasks will be done under supervision
What are the tasks expected to be accomplished by the student?
Take blood sample by venous puncture in established patients and analyse the concentration of acetylcholinesterase by means of laboratory work using the Worek method (modified Ellman colorimetric assay). It will also apply surveys to these same patients to assess their mental health. Finally, the student will work with the information obtained in a database using SPSS software package 21.0 (Chicago, USA) for all statistical evaluation, and with it, obtain conclusive results of the project.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
Upon arrival of the student at the research department, a theoretical training will be given by the tutor of topics related to the project: -Activity of acetylcholinesterase -Function of the sympathetic nervous system -Effect of organophosphates in the central nervous system and, In addition, a practical training for the standardization of: -Immunoassay techniques -Recollection and preparation of biological samples -Application of test -Management of confidentiality and bioethics
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a presentation - The student will prepare a scientific report
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
Know how to work with in vitro assays and micropipettes and know how to take blood samples by means of venipuncture with vacutainer equipment in patients of all ages.
Are there any legal limitations in the student’s involvement
Type of students accepted
This project accepts: - Medical students
- Aracely Serrano-Medina; Angel Ugalde-Lizárraga; Michelle Stephanie Bojorquez-Cuevas; Jatniel Garnica-Ruiz; Martín Alexis González-Corral; Arnold García-Ledezma;Gisela Pineda-García and José Manuel Cornejo-Bravo (2019). Neuropsychiatric Disorders in Farmers Associated with Organophosphorus Pesticide Exposure in a Rural Village of Northwest Mexico. International Journal of Environmental Research and Public Health; 16 (5); 689; doi:10.3390/ijerph16050689
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