RESUMEN
Methanol has been proposed in different countries as an alternative automotive fuel to be used as an additive to, or replacement for, gasoline or ethanol. Utilization of methanol is increasing exposure to low levels of methanol vapors in the environment and more specifically in occupational settings such as gas stations. Pump operators are exposed to relatively high levels of fuel vapors, the consequences of which have not been fully examined. In this study, the micronucleus assay in squamous oral cells was performed on pump operators of 28 gas stations in three different periods in the city of São Paulo, Brazil. The frequency of micronuclei (MN) was evaluated before and 1 year after a mixed fuel called MEG, which contains 33% methanol, 60% ethanol and 7% gasoline, was introduced. The third evaluation, 3 years later, represents a period where the number of cars using alcohol fuel had decreased drastically and the pump operator exposure to MEG became very low. The frequency of MN observed in 76 employees in 1992 (mean = 3.62 +/- 0.39) was significantly increased (P < 0.001) as compared with 76 operators exposed in 1989 (mean = 1.41 +/- 0.26) and 129 exposed in 1995 (mean = 1.20 +/- 0.15). These differences were also significant when compared with control groups not exposed professionally to motor fuel. These findings could indicate a mutagenic hazard of the MEG occurring in those with occupational exposure.
Asunto(s)
Metanol/efectos adversos , Micronúcleos con Defecto Cromosómico/efectos de los fármacos , Mucosa Bucal/efectos de los fármacos , Boca/efectos de los fármacos , Exposición Profesional/efectos adversos , Solventes/efectos adversos , Adulto , Análisis de Varianza , Brasil/epidemiología , Humanos , Micronúcleos con Defecto Cromosómico/patología , Persona de Mediana Edad , Boca/patología , Mucosa Bucal/patología , Petróleo/efectos adversos , Análisis de RegresiónRESUMEN
The effects of ivermectin, a semi-synthetic drug widely used for treatment of livestock parasite diseases, were observed on Culex quinquefasciatus larvae. Toxic effects and mortality evaluation were carried out after 5, 15, 30 and 60 minutes of exposure to 1, 5 or 10 ppm of ivermectin solutions. Observations were made 24 and 48 hours after the beginning of the experiment, and loss of mobility, progressive paralysis and high mortality of larvae were recorded. The observed effects of ivermectin on the mosquito larvae is probably correlated with chloride channel activation on cell membranes.