Sample records for aberracoes cromossomicas instaveis
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Energy Technology Data Exchange (ETDEWEB)
Fernandes, Thiago de Salazar e
2005-02-15
Biodosimetry is based on the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. The quantification of unstable chromosome aberrations and micronuclei, in peripheral blood lymphocytes, are two methods commonly used in biodosimetry. In this context, the aim of this research was to compare these methods in the biomonitoring of health care professionals occupationally exposed to ionizing radiation. In parallel, the technique of C-banding was evaluated for quality control of unstable chromosome aberrations analyses. Thus, samples of peripheral blood from health care professionals of three hospitals from Recife (Brazil) were collected, and the lymphocytes cultures were carried out based on the cytogenetic classical technique. It was pointed out that analysis of micronuclei is faster than the unstable chromosome aberrations ones, which suggests the use of the former in preliminary evaluation in cases of suspected accidental exposure. C-banding technique was efficient, as confirmatory test, in the identification of dicentrics and rings during the analyses of unstable chromosome aberrations, being able to be applied in the quality control in biodosimetry. The comparison between the individual work conditions with the frequencies of unstable aberrations and micronuclei obtained from cytogenetic analysis, resulted in the change of behavior of the professionals involved in this research, with a better observance of the radioprotection standards. (author)
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Energy Technology Data Exchange (ETDEWEB)
Magnata, Simey de Souza Leao Pereira
2002-09-01
Absorbed dose determination is an important step for risk assessment related to an exposure to ionizing radiation. However, physical dosimetry cannot be always performed, principally in the case of retrospective estimates. In this context, the use of bioindicators (biological effects) has been proposed, which defines the so-called biological dosimetry. In particular, scoring of unstable chromosomes aberrations (dicentrics, centric rings and fragments) of peripheral blood lymphocytes, while is the most reliable biological method for estimating individual exposure to ionizing radiation. In this work, blood samples from 5 patients, with cervical uterine cancer, were evaluated after partial-body radiotherapy with a source of {sup 69} Co. For this, conventional cytogenetic method was employed, based on Giemsa coloration and fluorescence in situ hybridization, in order to correlate the frequency of unstable chromosome aberrations of blood lymphocytes with absorbed dose, as a result of the radiotherapy. A good agreement was observed between the frequency of chromosome aberrations scored and the values of dose previously calculated by physical dosimetry during patient's radiotherapy. The results presented in this work point out the importance of concerning analyses of unstable chromosome aberrations as biological dosimeter in the investigation of partial-body exposure to ionizing radiation. (author)
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Energy Technology Data Exchange (ETDEWEB)
Magnata, Simey de Souza Leao Pereira
2002-09-01
Absorbed dose determination is an important step for risk assessment related to an exposure to ionizing radiation. However, physical dosimetry cannot be always performed, principally in the case of retrospective estimates. In this context, the use of bioindicators (biological effects) has been proposed, which defines the so-called biological dosimetry. In particular, scoring of unstable chromosomes aberrations (dicentrics, centric rings and fragments) of peripheral blood lymphocytes, while is the most reliable biological method for estimating individual exposure to ionizing radiation. In this work, blood samples from 5 patients, with cervical uterine cancer, were evaluated after partial-body radiotherapy with a source of {sup 69} Co. For this, conventional cytogenetic method was employed, based on Giemsa coloration and fluorescence in situ hybridization, in order to correlate the frequency of unstable chromosome aberrations of blood lymphocytes with absorbed dose, as a result of the radiotherapy. A good agreement was observed between the frequency of chromosome aberrations scored and the values of dose previously calculated by physical dosimetry during patient's radiotherapy. The results presented in this work point out the importance of concerning analyses of unstable chromosome aberrations as biological dosimeter in the investigation of partial-body exposure to ionizing radiation. (author)
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Energy Technology Data Exchange (ETDEWEB)
Yunes, Samira Nogarol
2010-07-01
The municipality of Monte Alegre is a region that presents natural radiation high due to the presence of the radionuclide uranium ({sup 238}U) in its soil, which through its decay gives rise to element Rn, a gas. The radioactivity of the rocks has become a problem for the population of Monte Alegre, from the moment when the radioactive material began to be used in the construction of houses and paving of streets. Among all bio markers related to environmental exposures and its biological effects, the chromosomal aberrations are considered good bio markers as predictors of the risk of cancer. Studies suggest that the frequency of chromosomal aberrations may be related to the genetic instability individual and/or exposure to ionizing radiation. Our work aimed to evaluate the frequency of chromosomal aberrations in individuals in the region of high natural radioactivity in Monte Alegre-PA. As well as to correlate the cytogenetic analysis made in this study with the results of analysis of frequency of polymorphisms of genes of DNA repair carried out in another study that resulted in other dissertation. In accordance with the distribution of the data obtained in characterizing environmental radiological and in the calculation of dose, were chosen residents of homes with more and less exposure to radiation. The samples of peripheral blood of 85 individuals of the resident population of the region of Monte Alegre - PA were collected and examine provided two slides for individual was performed to verify the quality of the sample. Through this evaluation we decide that 33% of the material collected, or is, samples of 28 individuals were in suitable conditions for analysis of the frequency of chromosomal aberrations. After the collections lymphocytes present in the sample were cultivated in accordance with the methodology proposed for obtaining of cells in metaphase. were analyzed 6,177 metaphases of 28 individuals among which were found dicentric chromosomes 4 and 19 fragments. The number of chromosomal aberrations exceeded the interval of the values of reference for the frequency of basal dicentric. Thus the exposure to radiation, produced by decay of uranium, in the residences of Monte Alegre is not sufficient to increase the frequency of chromosomal aberrations-type unstable for the study group. We cannot say that the combination of variations polymorphic found in individuals had influences the emergence of aberrations, given that several factors may be involved to the emergence of spontaneous chromosomal aberrations. (author)
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Energy Technology Data Exchange (ETDEWEB)
Mendonca, Julyanne C.G.; Mendes, Mariana E.; Lima, Fabiana F., E-mail: july_cgm@hotmail.com, E-mail: mendes_sb@hotmail.com [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Santos, Neide, E-mail: santos_neide@yahoo.com.br [Universidade Federal de Pernambuco (CCB/UFPE), Recife, PE (Brazil). Departamento de Genetica
2013-07-01
The aim of this study was to analyze the frequency of unstable chromosomal aberrations induced by gamma radiation from a {sup 60}Co source at two different doses. Samples were obtained from a healthy donor and exposed to {sup 60}Co source (Gammacel 220 ) located in the Department of Nuclear Energy of Pernambuco Federal University (DEN/UFPe/Brazil) with a rate of air Kerma to 3,277 Gy/h. Exposures resulted in absorbed dose 0.51 Gy and 0.77 Gy. Mitotic metaphases were obtained by culturing lymphocytes for chromosome analysis and the slides were stained with 5% Giemsa. Among the unstable chromosomal aberrations the dicentric chromosomes, ring chromosomes and acentric fragments were analyzed. To calculate the significance level the chi - square test was used, considering relevant differences between the frequencies when the value of p < 0.05. To calculate the significance level of the chi - square test was used, considering relevant differences between the frequencies when the value of p < 0.05. The results showed that there was significant difference of the frequencies of dicentric chromosomes (from 0.18 to 0.51 to 0.37 Gy to 0.77 Gy), however there was no statistically significant difference between the frequencies of acentric fragments ( 0.054 to 0, 51 Gy to 0.063 to 0.77 Gy) and ring chromosomes (0.001 to 0.51 Gy to 0.003 to 0.77 Gy). The low number of rings is found justified, considering that in irradiated human lymphocytes, its appearance is rare relative to dicentrics. The results confirm that dicentrics are the most reliable biomarkers in estimating dose after exposure to gamma radiation. These two points will make the calibration curve dose-response being built for Biological Dosimetry Laboratory of CRCN-NE/CNEN.
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Directory of Open Access Journals (Sweden)
Valeriana Moura Ribeiro
1976-06-01
Full Text Available Os autores registram um caso raro de retardo mental e malformações físicas em paciente com anormalidades cromossômicas. A análise cromossômica do paciente revelou cariótipo aparentemente equilibrado. Entretanto, são consideradas as possibilidades de que nos eventos de quebra e rejunção dos cromossomos, tenha ocorrido perda de alguns genes para 5p e/ou 13q; mutação gênica ou, ainda, efeito de posições dos segmentos cromossômicos rearranjados.An unusual case of mental retardation and physical malformations with chromosome abnormalities in a 9 year old boy is reported. Chromosomal analy- sis showed either breakage and delation from some gens to 5p and/or 13q; genic mutation or, perhaps, efect of position in re-adjusted chromosomic segments.
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Manninen, Noora Kristiina Alves de Sousa
diferentes componentes mecanicos sujeitos a elevado desgaste tribologico. Neste sentido, a combinacao das propriedades intrinsecas destes materiais pode ser considerada uma abordagem promissora para o desenvolvimento de revestimentos multifuncionais, os quais podem ser aplicados em diferentes produtos, nomeadamente, dispositivos medicos. Na presente tese os revestimentos nanocompositos de Ag/a-C sao depositados por dois metodos distintos: (i) pulverizacao catodica em magnetrao e (ii) combinacao da pulverizacao catodica em magnetrao para deposicao da camada de a-C e condensacao em atmosfera inerte para a incorporacao simultanea de nanoparticulas de Ag na matrix de carbono. Os metodos acima mencionados sao comparados em relacao a uniformidade dos revestimentos depositados, permitindo efetuar a escolha do metodo de deposicao mais eficaz (pulverizacao catodica em magnetrao). Os revestimentos nanocompositos de Ag/a-C sao caraterizados relativamente a sua estrutura, estabilidade termodinamica em condicoes ambientais e propriedades funcionais (comportamento tribologico e atividade antibacteriana). O trabalho central da tese e focado na caraterizacao de revestimentos Ag/a-C contendo 20% at. de Ag, com diferentes espessuras e diferentes estruturas em multicamada. Os resultados sugerem que os revestimentos Ag/a-C sao instaveis mesmo em condicoes ambientais, sendo observado que a Ag e forma nanofibras entre as fronteiras das colunas, as quais recobrem a superficie do revestimento poucas semanas apos a producao. O processo de formacao de nanofibras e promovido pela humidade, sendo que, as particulas crescem atraves de um processo de coalescencia. As propriedades funcionais sugerem que os revestimentos Ag/a-C sao promissores do ponto de vista de actividade antibacteriana, a qual esta relacionada com a sua ionizacao. Os testes tribologicos revelam que em ambiente nao lubrificado a presenca da Ag promove a degradacao dos revestimentos a-C, contudo, em meios biologicos que simulam o liquido