Assuntos
Síndrome de Down , Doenças do Nervo Óptico , Neuropatia Óptica Isquêmica , Oclusão da Artéria Retiniana , Humanos , Síndrome de Down/complicações , Oclusão da Artéria Retiniana/complicações , Oclusão da Artéria Retiniana/diagnóstico , Doenças do Nervo Óptico/diagnóstico , Doenças do Nervo Óptico/etiologia , Nervo ÓpticoAssuntos
Distrofias Hereditárias da Córnea , Córnea , Humanos , Piperazinas/efeitos adversos , PiridinasRESUMO
An alpha-dose calculation due to radon uptake in anthers of Tradescantia, clone 4430, has been performed. Probability distribution density of the dose in the pollen mother cells was calculated by means of a model that simulates the interaction of separate alpha-particles with these cells. It is shown that alpha-radiation from either radon or its decay products surrounding the buds does not reach pollen mother cells because of the short-range alpha-particles. However, it is suggested that radon diffuses through the gap structure of the bud to the anther from which a radon-gas adsorption process takes place. Absorbed-dose calculations in the anther are discussed as well as their relationship to the experimental results of micronucleus induction in pollen mother cells. The radon concentration interval used (0.85 kBq m(-3)-98.16 kBq m(-3)) is equivalent to the exposure to an average environmental radon concentration (40 Bq m(-3)) for 2.3 months or 22.1 years, respectively. The lowest radon concentration to induce micronuclei was 12.1 kBq m(-3), which is 15 times in excess of that adopted for old buildings in Canada.
Assuntos
Contaminação Radioativa de Alimentos , Plantas/efeitos da radiação , Radiometria/métodos , Radônio , Poluição do Ar em Ambientes Fechados , Partículas alfa , Relação Dose-Resposta à Radiação , Testes para Micronúcleos , Modelos Teóricos , Plantas/genética , Pólen , Produtos de Decaimento de Radônio , Tradescantia/efeitos da radiação , VerdurasRESUMO
Inflorescences of Tradescantia clone 4430 were exposed to different concentrations of radon (Rn) gas (0.85, 12.10, 36.50 and 98.16 kBq/m3) from plants placed in an acrylic chamber that received radon from a container with pitchblende (containing uranium mineral). The exposure time was 24 h, afterwards the plants were left for 6 h in water and constantly aerated. Positive control plants were irradiated with gamma rays (0.8 Gy) and negative control plants received ambient air only (the background measurement had a mean of 0.38 kBq/m3). Micronuclei (MCN) in the tetrads induced by alpha particles emitted from Rn were tabulated and a linear concentration response was obtained. The potency of radon to induce MCN from the slope of the regression line was 0.13 MCN/kBq/m3 of alpha-radiation. Radon could reach the anthers by diffusion through the aerial spaces within the buds.
