Cytogenetic effects from exposure to mixed pesticides and the influence from genetic susceptibility.

Abstract

Exposure to pesticides remains a major environmenal health problem. Health risk from such exposure needs to be more precisely understood. We conducted three different cytogenetic assays to elucidate the biological effects of exposure to mixed pesticides in 20 Costa Rica farnMrs (all nonsmokers) compared with 20 matched controls. The farmers were also exposed to dibromochloropropane during the early employment years, and most of them experienced sterility/fertility problems. Our data show that the famers had consistently higher frequencies of chromosome aberrations, as determined by the standard chromosome aberration assay, and significandy abnormal DNA repair responses (p c 0.05), as determined by the challenge assay, but no statistically significant differences in the tandem-probe fluorescence in situ hybridization (FISH) assay (p > 0.05). Genotype analysis indicates that farmers with certain "unfavorable" versions of polymorphic metabolizing genes (cytochrome P4502El, the glutathione S-transferases mu and theta, and the paraoxonase genes) had significantly more biological effects, as determined by all three cytogenetic assays, than both the farmers with the "favorable" alleles and the matched controls. A unique observation is that, in individuals who had inherited any of the mentioned "unfavorable" alleles, farmers were consistentdy underrepresented. In condusion, the Costa Rican farmers were exposed to genotoxic agents, most likely pesticides, which expressed the induction of biological and adverse health effects. The farmers who had inherited "unfavorable" metabolizing alleles were more susceptible to genotoxic effects than those with "favorable" alleles. Our genotype data suggest that the well-recognized "healthy worker effect" may be influenced by unrecognized occupational selection pressure against genetically susceptible individuals.

Aberraciones cromosómicas en trabajadoras expuestas a plaguicidas

“…El único estudio de este tipo realizado en trabajadores costarricenses fue llevado a cabo por investigadores de la Universidad de Texas. Incluyeron veinte hombres afectados de problemas reproductivos causados por la exposición laboral al DBCP, no encontraron diferencia significativa entre casos y controles, 1.6% de células anormales contra el 1.26% del grupo control (Au et al 1999). La exposición a este plaguicida había ocurrido en los años sesentas y setentas, por lo que la mayoría de los sujetos estudiados ya estaban retirados de las labores agrícolas cuando se analizaron sus cromosomas.…”

“…La fuerte asociación que existe entre aberraciones cromosómicas y la formación de tumores hace que su análisis en poblaciones de alto riesgo sea considerado un método apropiado para estudiar clastogenicidad y se consideran un buen predictor de carcinogenicidad (Nordenson et al 1984, Sorsa et al 1992, Hagmar et al 1994, Au et al 1999, Preston 1999, Bonassi y Au 2002. Tanto las sustancias químicas que reaccionan directamente con el ADN, como algunas de las consideradas mutágenos indirectos, llamados equivocadamente no genotóxicos, pueden producir aberraciones cromosómicas (Preston 1999).…”

“…Un aumento en la frecuencia de aberraciones cromosómicas en trabajadores expuestos a mezclas de plaguicidas ha sido informado por varios estudios; sin embargo, los hallazgos no son consistentes en todos ellos debido a las diferentes variables que influyen en los resultados, tales como el tipo de plaguicida y la duración y la intensidad de la exposición (Au et al 1999).…”

Molecular Epidemiology Studies on Occupational and Environmental Exposure to Mutagens and Carcinogens, 1997-1999

“…They were determined in 13 studies. In 11 studies effects of exposure to PAHs in coke ovens (7), hydrocarbons (25), benzene (31,32), acrylonitrile together with dimethyl formamide (35), BD (37,39), pesticides in farmers (41), fluorides (47), cytostatics (49), and cosmic radiation (54) were observed. Only in two studies, greenhouse workers exposed to pesticides (44) and crews exposed to cosmic radiation (55), were no effects of exposure found.…”

Organik ve Organik Olmayan Elmalar ile Bu Elmaları Üreten Kişilerdeki Pestisit Kalıntıları ve Toplam Antioksidan Kapasiteleri

“…Bu bileşikler kullanıldıktan sonra farklı kaynaklardan atıksulara karışmakta, atıksu arıtma tesislerinde yeterli miktarda giderilemediği için doğal sularda, içme suyu kaynaklarında, hatta beslenme zincirlerinde birikmektedir. Bazı çalışmalar, pestisitlerin, insan sağlığı üzerine, nevrit, psikiyatrik, karaciğer-böbrek fonksiyon bozukluğu, elektroensefalograf değişiklik, bağışıklık sistemine olumsuz etkileri, metabolik sorunlar, endokrin lösemi ve mesane kanseri gibi zararlı etkilerinin olduğunu göstermiştir [1][2][3][4].…”