LBDNet interlaboratory comparison for the dicentric chromosome assay by digitized image analysis applying weighted robust statistical methods.

PURPOSE: This interlaboratory comparison was conducted to evaluate the performance of the Latin-American Biodosimetry Network (LBDNet) in analyzing digitized images for scoring dicentric chromosomes from in vitro irradiated blood samples. The exercise also assessed the use of weighted robust algorithms to compensate the uneven expertise among the participating laboratories. METHODS: Three sets of coded images obtained through the dicentric chromosome assay from blood samples irradiated at 1.5 Gy (sample A) and 4 Gy (sample B), as well as a non-irradiated whole blood sample (sample C), were shared among LBDNet laboratories. The images were captured using the Metafer4 platform coupled with the AutoCapt module. The laboratories were requested to perform triage scoring, conventional scoring, and dose estimation. The dose estimation was carried out using either their laboratory calibration curve or a common calibration curve. A comparative statistical analysis was conducted using a weighted robust Hampel algorithm and z score to compensate for uneven expertise in dicentric analysis and dose assessment among all laboratories. RESULTS: Out of twelve laboratories, one had unsatisfactory estimated doses at 0 Gy, and two had unsatisfactory estimated doses at 1.5 Gy when using their own calibration curve and triage scoring mode. However, all doses were satisfactory at 4 Gy. Six laboratories had estimated doses within 95% uncertainty limits at 0 Gy, seven at 1.5 Gy, and four at 4 Gy. While the mean dose for sample C was significantly biased using robust algorithms, applying weights to compensate for the laboratory's analysis expertise reduced the bias by half. The bias from delivered doses was only notable for sample C. Using the common calibration curve for dose estimation reduced the standard deviation (s*) estimated by robust methods for all three samples. CONCLUSIONS: The results underscore the significance of performing interlaboratory comparison exercises that involve digitized and electronically transmitted images, even when analyzing non-irradiated samples. In situations where the participating laboratories possess different levels of proficiency, it may prove essential to employ weighted robust algorithms to achieve precise outcomes.

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)

Nuevas curvas de calibración para la dosimetría biológica en Cuba / New calibration curves for biological dosimetry in Cuba

RESUMEN Se muestran 11 curvas dosis respuesta in vitro obtenidas por primera vez en el país para tres indicadores biológicos: anillos en cromosomas prematuramente condensados (PCC-R) índice PCC; focos gamma H2AX (-H2AX), todos ellos en linfocitos de sangre periférica humana. Estas curvas en su conjunto cubren un intervalo de dosis desde 0,1 Gy hasta 25 Gy, y varias calidades de radiación, así como varios tiempos post exposición, lo cual fortalece las capacidades para dar respuesta a las emergencias radiológicas y amplía las posibilidades de contribuir al esclarecimiento de cualquier suceso radiológico anormal que pueda ocurrir en la región, donde el indicador predominante en la actualidad continúa siendo la cuantificación de dicéntricos en linfocitos de la sangre periférica.

ABSTRACT In this paper we show the dose response curves in vitro obtained at first time in Cuba, with several biological indicators for radiation damage: rings in premature chromosome condensation (PCC-R); PCC index and -H2AX foci, all of these in peripheral human lymphocytes. These curves cover an interval of doses between 0.1 Gy to 25 Gy, several radiation qualities and times post-exposition, strengthening the capabilities of the Cuban laboratory to give answer to the radiological emergencies and in the same way increase its contribution to elucidate any radiological abnormal event take place at the region where the main indicator at the present time is the dicentric assay in lymphocytes of peripheral blood.

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

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