Biomonitoreo de trabajadores expuestos a plaguicidas / Biomonitoring of workers exposed to pesticides

Se realizó el biomonitoreo de los trabajadores de la planta formuladora de plaguicidas de Managua con el objetivo de conocer si la manipulación de plaguicidas, descritos como mutágenos químicos potenciales, había causado efecto genotóxico. Se estudió el daño primario al ADN mediante el ensayo cometa y el daño cromosómico mediante aberraciones cromosómicas en linfocitos y micronúcleos en células exfoliadas de la mucosa bucal. Para los análisis de los datos se utilizaron el porcentaje de ADN en la cola, el porcentaje de células con aberraciones cromosómicas y el porcentaje de células con micronúcleos. Las frecuencias de aberraciones cromosómicas y de células con micronúcleos tanto en el grupo expuesto como en el grupo control se encuentran dentro del intervalo reportado para muestras de la población cubana. Los valores del porcentaje de ADN en la cola analizados por el ensayo cometa en el grupo expuesto no mostraron diferencias significativas antes y después de la jornada laboral. Los resultados analizados evidencian que la manipulación de plaguicidas por este grupo de trabajadores no ha inducido daño genético detectable por los métodos empleados(AU)

A biomonitoring of workers of the pesticide formulation plant from Managua municipality to know if the manipulation of pesticides described as potential chemical mutagens, had a genotoxic effect was carried out. The primary damage of DNA was studied by means of the comet assay and the chromosomal damage by chromosomal aberrations in lymphocytes and micronuclei in exfoliated cells of oral mucosa. For data analysis the DNA percentage in tail, the percentage of cells with chromosomal aberration and the percentage of cells with micronuclei were used. The frequency of chromosomal aberrations and of cells with micronuclei, both, in the exposed group and in the control one are within the interval reported for samples of Cuban population. The values of DNA percentage in tail, analyzed by comet assay in exposed group not showed significant differences before and after working day. The results analyzed demonstrate that manipulation of pesticides by this group of workers has not provoked any genetic damage perceptible by methods used(AU)

Sensitivity and variability of visual scoring in the comet assay. Results of an inter-laboratory scoring exercise with the use of silver staining.

Nineteen scorers from seven Cuban laboratories participated in this slide exercise designed to test the influence of the scorer on the accuracy, sensitivity and variability of the comet assay when a visual method of DNA damage evaluation is used. The assay was performed using human lymphocytes from a single donor exposed in vitro for 5 min at 0 degrees C to doses of 0, 5, 10, 25, 50, 100 and 200 microM of hydrogen peroxide. Each participant scored the same set of 14 coded slides with silver stained comets. The comets were classified visually into five categories according to the appearance resulting from the relative proportion of DNA in the tail. The extent of DNA damage was expressed in arbitrary units. At zero dose the median values of 12 scorers out of 19 were included between the values of the overall 25 and 75 per thousand. This proportion remains practically the same as the dose increases. The lowest dose detected by this method for the majority of scorers (11) was 10 microM. The coefficient of variation at the control dose was the highest (median value 26%), progressively declined to 20%, and starting from 25 microM, values are around 10%. The results of the exercise show the reliability of the silver staining and visual scoring for the comet method.

Anesthesia of fish with benzocaine does not interfere with comet assay results.

Fish blood erythrocytes are frequently used as sentinels in biomonitoring studies. Usually, fish blood is collected by painful cardiac or caudal vein punctures. Previous anesthesia could decrease animal suffering but it is not known at present whether anesthesia can cause confounding effects. Therefore, using the alkaline single cell gel (SCG)/comet assay with blood erythrocytes of the cichlid fish Nile tilapia, we tested for a possible modulation of induced DNA damage (methyl methanesulfonate; MMS) by the anesthetic benzocaine administered by bath exposure (80mg/l for approximately 10min). Furthermore, benzocaine (80-600mg/l) was tested for its genotoxic potential on fish erythrocytes in vitro and for potential interactions with two known genotoxins (MMS and hydrogen peroxide). Our results did neither indicate a significant increase in the amount of DNA damage (even after a 48h follow-up), nor indicated interactions with MMS-induced DNA damage when fish were exposed to benzocaine in vivo. There was also no increase in DNA damage after in vitro exposure of fish erythrocytes to benzocaine. Clear concentration-related effects were observed for the two genotoxins in vitro, which were not significantly altered by the presence of benzocaine. These results suggest that anesthesia of fish does not confound comet assay results and the use of blood samples from anesthetized fish can be recommended with regard to animal welfare.