Mayor frecuencia de aberraciones cromosómicas en linfocitos expuestos o no a mitomicina C, de mujeres posmenopáusicas obesas en comparación con mujeres no obesas del departamento del Cauca, Colombia / High frequency of chromosome aberrations observed in lymphocytes in postmenopausal obese women

Introducción. Los estudios epidemiológicos indican que la obesidad está asociada en el 25 al 30 % con varios tipos de cáncer. Objetivo. Evaluar la frecuencia de aberraciones cromosómicas en linfocitos de mujeres posmenopáusicas obesas y no obesas, mediante la prueba de reto celular (challenge assay) como biomarcador de inestabilidad genómica. Materiales y métodos. Cuarenta mujeres posmenopáusicas fueron incluidas en el estudio (20 obesas y 20 no obesas). Los grupos fueron pareados según edad (± 5 años) y procedencia. Después de la firma voluntaria del consentimiento informado, las mujeres fueron entrevistadas y se les tomó una muestra de 5 ml de sangre periférica. Se establecieron cultivos de linfocitos con tratamiento con mitomicina C y sin él (prueba de reto celular) y, posteriormente, se registró la frecuencia de aberraciones cromosómicas para cada grupo y tratamiento. Resultados. En general, las mujeres obesas presentaron una mayor frecuencia de aberraciones cromosómicas en comparación con las no obesas. Después de exponer los cultivos celulares a mitomicina C, las mujeres obesas presentaron un incremento en el número de aberraciones cromosómicas totales en comparación con las no obesas (3,74±0,63 Vs. 2,70±0,61; p=0,001). Conclusiones. La mayor frecuencia de aberraciones cromosómicas en los linfocitos de mujeres posmenopáusicas obesas que en no obesas, sugiere diferencias en la capacidad de reparación del ADN, lo cual podría explicar la asociación entre la inestabilidad genómica y la mayor incidencia de cáncer en esta población.

Introduction. Epidemiological studies indicate that obesity is associated with an increased risk of 20-25% with several types of cancer. Objective. The frequency of chromosome aberrations was evaluated in lymphocytes from postmenopausal obese and non-obese women. Materials and methods. Twenty obese and 20 non-obese women, all post-menopause, were recruited. The groups were matched according to age (± 5 years) and place of origin. After signing the consent form, women were interviewed using a structured questionnaire, and a blood sample (5 ml) was drawn into vacutainer tubes. From each sample, lymphocyte cell cultures were established with and without mitomycin C (challenge assay). Afterwards, the frequency of chromosome aberrations were recorded for each group and treatment. Data were analyzed using the statistical program SPSS, v. 14.0. Results. Obese women had a higher frequency of chromosome aberrations when compared with non-obese women. After exposing the cell cultures to mitomycin C, obese women presented an increase in the number of total chromosome aberrations in comparison to non-obese women (3.7± 0.6 vs. 2.70±0.6; p=0.001). Conclusions. The higher frequency of chromosome aberrations in lymphocytes from postmenopausal obese women compared to non-obese women suggested differences in the DNA repair capacity. This may indicate an association between genomic instability and the higher incidence of cancer in this population.

Efeitos clastogenicos causados por varios sorotipos de Ureaplasma urealyticum e especies do genero Mycoplasma sobre culturas temporarias de linfocitos / Clastogenic effects caused by serotypes of Ureaplasma urealyticum and species of the genus Mycoplasma on linphocytes temporary cultures

Os efeitos clastogenicos causados por diferentes cepas Ureaplasma urealyticum e por cepas do genero Mycoplasma foram avaliados in vitro, utilizando-se culturas temporarias de linfocitos humanos. Os resultados obtidos neste modelo experimental in vitro, revelaram haver comportamentos diferentes entre os varios sorotipos de Ureaplasma urealyticum e entre especies do genero Mycoplasma. Essas diferencas observadas in vitro poderao de alguma forma contribuir para melhor compreensao dos efeitos da colonizacao desses microorganismos em humanos

Correlation of fragile sites and bleomycin induced chromosome break points.

Bleomycin (Blm) induced break points in human chromosome preparations were compared with the known fragile sites. A total of 136 breaks were observed from 100 well spread G-banded plates (1.3 bps/cell). These correspond to a total of 57 break prone sites. Of these 57 sites, 24 correspond to the known fragile sites, 5 to sites of protooncogenes and neoplasia, 26 sites correspond to more than one known site of fragility, protooncogene, neoplasia or reciprocal translocation sites, and 2 unknown sites. The findings suggest that fragile sites, either commonly expressed or induced, might be a predisposing factor for chromosome aberrations in human. The expression of fragile sites induced by Blm and their correlation with the known cancer chromosome break points, oncogenes and reciprocal translocation, suggest that the fragile sites are prone to mutagenic action.