The level of exposure affects the arsenic urinary methylation profile of a population of children.

Differences in the As methylation capacity of Argentine children, exposed to different levels of As in drinking water were evaluated, considering the gender and the presence of the As3MT T860C gene polymorphism. Inorganic As (%IAs), monomethylated As (%MMA) and dimethylated As (%DMA), primary methylation index (PMI) and secondary methylation index (SMI) were evaluated and represented the As methylation capacity. Urinary As ranged from 18 to 5106 µg/g creatinine. Comparisons were performed between lowest and highest quartiles of urinary As. The level of exposure was positively related to urinary %MMA and negatively to %DMA and to SMI. Considering the presence of the As3MT T860C polymorphism, the level of exposure increased %MMA, and decreased %DMA and the SMI in carriers of the T/T genotype. SMI OR for T/T carriers was 10.61 (95% CI: 2.16-52.16, p: 0.0036). Regarding the gender, the level of exposure increased %MMA, and decreased %DMA and the SMI in girls and boys. SMI OR for girls was 8.71 (95% CI: 1.48-51.08, p: 0.0165) and for boys, OR: 18.15 (95% CI: 2.03-162.35, p: 0.0095). It was possible to identify the level of exposure as a factor that can modify the influence that other factors have on the methylation of As.

Participación de la Cotinina en la abstinencia nicotínica en ratas (Estudio preliminar) / Cotinine participation in chronic nicotinic withdrawal syndrome in rats (Preliminary study)

Numerosos datos clínicos y experimentales han demostrado que la nicotina del tabaco (NI) es la razón de la adicción al tabaco en los seres humanos, a través de la inducción de la tolerancia y la dependencia física. El humo del tabaco contiene otros alcaloides que pueden contribuir a la adicción, como la cotinina (COT). En este estudio se evaluaron los posibles efectos de la COT en ratas durante el síndrome de abstinencia nicotínica midiendo la actividad locomotora espontánea (ALE) utilizando el test del campo abierto. El estudio se llevó a cabo con dos grupos de ratas que recibieron NI 10 mg / kg / día en agua potable durante 120 días (grupos A y B). Luego, en el grupo A, se sustituyó NI por agua potable y en el grupo B, sustituido por COT 12 mg / kg, durante 24 horas en ambos grupos. La actividad locomotora espontánea se registró al final del día 120 (nivel basal) y al final del día 121, al final del período de abstinencia. Los resultados obtenidos se compararon con las mediciones basales. El grupo A mostró diferencias significativas en 3 de los 9 movimientos medidos y el grupo B mostró diferencias significativas en 7 de los 9 movimientos medidos. Cuando el grupo A se comparó con el grupo B sólo 1 movimiento mostró diferencia significativa. Estos resultados sugieren que en la administración crónica de nicotina y en estas condiciones experimentales, la cotinina participa en el síndrome de abstinencia nicotínica

A large amount of clinical and experimental data has shown that tobacco nicotine (NI) is the reason for tobacco addiction in humans, through the induction of tolerance and physical dependence. Tobacco smoke contains other alkaloids that may contribute to addiction, such as cotinine (COT). In this study we evaluated the possible effects of COT in rats during NI abstinence syndrome by measuring spontaneous locomotor activity (SLA) with an open field test. The study was carried out with two groups of rats receiving NI 10 mg / kg / day in drinking water for 120 days (groups A and B). Then, in group A, NI was replaced by drinking water and in group B, substituted by COT, 12 mg / kg, for 24 hours in both groups. Spontaneous locomotor activity was recorded at the end of day 120 (baseline) and at the end of day 121, the end of the abstinence period. The results obtained were compared against the baseline measurements and group A showed significant differences in 3 of the 9 movements measured and group B displayed significant differences in 7 of the 9 movements measured. When group A was compared with Group B only 1 movement showed any significant differences. These results suggest that cotinine participates in the nicotine withdrawal syndrome in chronic nicotine administration under these experimental conditions