Absence of genotoxic activity of beta-myrcene in the in vivo cytogenetic bone marrow assay

beta-Myrcene (MYR, 7-methyl-3-methylene-1,6 octadiene) is a peripheral analgesic substance and one of the major constituents of lemongrass oil (Cymbopogon citratus, Stapf), a plant widely used in Brazilian folk medicine. In the present study the genotoxicity of MYR was evaluated in vivo using the rat bone marrow cytogenetic assay. Male and female Wistar rats weighing 250 g (223 to 286 g) and 178 g (168 to 186 g), respectively, were used. Two or four rats of either sex were treated orally with MYR (0.1, 0.5 and 1.0 g/kg po), corn oil (negative control) and cyclophosphamide 30 mg/kg ip (positive control). Animals were sacrificed and bone marrow cells were harvested 24 and 48 h after MYR administration. The mitotic index and the frequency of chromosome aberrations were evaluated. Fifty metaphase cells were examined per animal. A dose related increase in mitotic index was observed 24-h after MYR administration. No evidence of MYR-induced clastogenicity was observed under the experimental conditions of this in vivo assay. The present results and previous negative findings of in vitro mutagenicity tests strongly indicate that MYR is not a genotoxic substance

Comparasion of polyacrylamide gel electrophoresis (PAGE), immuno-electron microscopy (IEM) and enzyme immunoassay (EIA) for the rapid diagnosis of rotavirus infection in children.

A evidenciacao da presenca de acido ribonucleico (ARN) viral por eletroforese em gel de policrilamida (EGPA) foi comprovada como um metodo altamente sensivel e rapido para o diagnostico de infeccoes por rotavirus. Uma comparacao desta prova com a imunomicroscopia eletronica (IEM) e com o ensaio imunoenzimatico (EIE) no exame de 245 fezes de criancas com gastroenterite revelou completa concordancia entre os tres ensaios em 238 (97.14%) amostras. Entre 75 amostras positivas pelo menos em um dos tres ensaios, resultados negativos foram observados em 5 (6.48%) por EGPA, em 6 (6.76%) por EIE e em nenhum por IEM. Coloracao pela prata aumentou consideravelmente a sensibilidade do ensaio por EGPA.Concluimos que embora a IEM ainda seja a prova mais sensivel e rapida para o diagnostico de infeccoes por rotavirus, o ensaio por EGPA tem muitas vantagens em seu favor, sendo as principais as de nao necessitar equipamentos caros, de empregar exclusivamente reagentes quimicamente definidos, de identificar grupos e variantes virais e de detectar amostras que nao possuindo antigenos comuns a maioria dos rotavirus, nao sao revelaveis por ensaios sorologicos