Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 9(1): 19919, 2019 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882739

RESUMO

The increased potential for tritium releases from either nuclear reactors or from new facilities raises questions about the appropriateness of the current ICRP and WHO recommendations for tritium exposures to human populations. To study the potential toxicity of tritium as a function of dose, including at a regulatory level, mice were chronically exposed to tritium in drinking water at one of three concentrations, 10 kBq.l-1, 1 MBq.l-1 or 20 MBq.l-1. Tritium was administered as either HTO or as tritiated non-essential amino acids (TAA). After one month's exposure, a dose-dependent decrease in red blood cells (RBC) and iron deprivation was seen in all TAA exposed groups, but not in the HTO exposed groups. After eight months of exposure this RBC decrease was compensated by an increase in mean globular volume - suggesting the occurrence of an iron deficit-associated anemia. The analysis of hematopoiesis, of red blood cell retention in the spleen and of iron metabolism in the liver, the kidneys and the intestine suggested that the iron deficit was due to a decrease in iron absorption from the intestine. In contrast, mice exposed to external gamma irradiation at equivalent dose rates did not show any change in red blood cell numbers, white blood cell numbers or in the plasma iron concentration. These results showed that health effects only appeared following chronic exposure to concentrations of tritium above regulatory levels and the effects seen were dependent upon the speciation of tritium.


Assuntos
Aminoácidos/química , Aminoácidos/farmacologia , Hematopoese/efeitos dos fármacos , Ferro/metabolismo , Trítio/química , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Água Potável/efeitos adversos , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Raios gama , Intestinos/citologia , Fígado/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL
2.
Radiat Environ Biophys ; 55(2): 161-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26961776

RESUMO

This study was designed to assess the feasibility of a noninvasive urine specimen for the detection of proteins as indicators of internal exposure to ionizing radiation. Three groups of rats (five in each group) were intravenously injected with 1601 ± 376, 10,846 ± 591 and 48,467 ± 2812 Bq of (210)Po in citrate form. A sham-exposed control group of five rats was intravenously injected with sterile physiological saline. Daily urine samples were collected over 4 days following injection. Purification and pre-concentration of urinary proteins were carried out by ultrafiltration using a 3000 Da molecular weight cutoff membrane filter. The concentration of common urinary proteins, namely albumin, alpha-1-acid glycoprotein, immunoglobulins IgA and IgG, was measured by an enzyme-linked immunosorbent assay. Urinary excretion of albumin decreased dose-dependently (p < 0.05) 96 h post-injection relative to the control group. In contrast, no statistically significant effects were observed for other proteins tested. The dose-dependent decrease in urinary excretion of albumin observed in this study underscores the need for further research, which may lead to the discovery of new biomarkers that would reflect the changes in the primary target organs for deposition of (210)Po.


Assuntos
Monitoramento Ambiental/métodos , Polônio/efeitos adversos , Proteinúria/urina , Amidoidrolases/urina , Animais , Biomarcadores/urina , Ensaio de Imunoadsorção Enzimática , Masculino , Ratos , Ratos Wistar , Ultrafiltração
3.
J Vis Exp ; (101): e52912, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-26168333

RESUMO

Low dose radiation exposure may produce a variety of biological effects that are different in quantity and quality from the effects produced by high radiation doses. Addressing questions related to environmental, occupational and public health safety in a proper and scientifically justified manner heavily relies on the ability to accurately measure the biological effects of low dose pollutants, such as ionizing radiation and chemical substances. DNA damage and repair are the most important early indicators of health risks due to their potential long term consequences, such as cancer. Here we describe a protocol to study the effect of chronic in vivo exposure to low doses of γ- and ß-radiation on DNA damage and repair in mouse spleen cells. Using a commonly accepted marker of DNA double-strand breaks, phosphorylated histone H2AX called γH2AX, we demonstrate how it can be used to evaluate not only the levels of DNA damage, but also changes in the DNA repair capacity potentially produced by low dose in vivo exposures. Flow cytometry allows fast, accurate and reliable measurement of immunofluorescently labeled γH2AX in a large number of samples. DNA double-strand break repair can be evaluated by exposing extracted splenocytes to a challenging dose of 2 Gy to produce a sufficient number of DNA breaks to trigger repair and by measuring the induced (1 hr post-irradiation) and residual DNA damage (24 hrs post-irradiation). Residual DNA damage would be indicative of incomplete repair and the risk of long-term genomic instability and cancer. Combined with other assays and end-points that can easily be measured in such in vivo studies (e.g., chromosomal aberrations, micronuclei frequencies in bone marrow reticulocytes, gene expression, etc.), this approach allows an accurate and contextual evaluation of the biological effects of low level stressors.


Assuntos
Partículas beta , Quebras de DNA de Cadeia Dupla , Reparo do DNA/efeitos da radiação , DNA/efeitos da radiação , Citometria de Fluxo/métodos , Raios gama , Animais , Medula Óssea , Histonas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos da radiação , Distribuição Aleatória
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...