Genotoxicity of tamoxifen citrate and 4-nitroquinoline-1-oxide in the wing spot test of Drosophila melanogaster.

Tamoxifen (TAM) is an anti-oestrogen used for treatment and prevention of human breast cancer, but it is also related to human endometrial and uterine cancer. The wing spot test in Drosophila melanogaster was employed to determine the genotoxic effects of TAM and 4-nitroquinoline-1-oxide (4-NQO), a carcinogen that produces adducts similar to TAM-DNA adducts detected in rodent liver and human liver microsomes. As Drosophila spp. have no oestrogen receptor, no effects can result in binding of TAM to a receptor. Chronic treatments with TAM citrate were performed with 3-day-old larvae of the standard (ST) and high bioactivation (HB) crosses of the wing spot test at concentrations of 0.66, 1.66 and 3.33 mM. In addition, the carcinogen 4-NQO was administered at 2.5 and 5.0 mM. Somatic spots on normal wings from marker-heterozygous flies and on serrate wings from balancer-heterozygous flies were scored to determine mutation and recombination events in somatic cells for each compound. The results showed genotoxic effects of TAM at 1.66 and 3.33 mM in the ST cross only and without a clear dose-response effect. This suggests a weak genotoxicity of this anti-oestrogen. The negative results obtained with TAM in the HB cross may indicate efficient detoxification of the compound by the increased xenobiotic metabolism present in this cross. As reported before, 4-NQO showed genotoxic effects in the ST cross with a clear dose-response effect. For the first time, we report enhanced effects of this compound in the HB cross. It is concluded that the genotoxicity of TAM in the Drosophila wing spot test is different from that of 4-NQO.

Educación ambiental / Environmental education

El presente libro fue elaborado con el propósito de que el alumno y el maestro aprendan juntos sobre su entorno inmediato: su casa, su persona, su escuela, su colonia, municipio, estado, país y planeta mediante el análisis y la toma de conciencia sobre la contaminación, los recursos naturales y las actividades del ser humano; todo, en beneficio de la comunidad. Incluye temas como las medidas para el control y tratamiento de la basura, la relación entre los problemas del ambiente y el Plan Nacional de Desarrollo, la relación entre el consumismo y el ambiente, artículos de primera necesidad y de lujo, desechos, medios de comunicación y ambiente, entre otros temas. Indice: 1. Contaminación producida por desechos materiales 2. La contaminación por la combustión y el ruido. Los medios de transporte y las industrias 3. Alteración del equilibrio ecológico por la deforestación 4. La contaminación social