Lesiones oculares y radiación ionizante / Eye injuries and ionising radiation

El número y la complejidad de los procedimientos de diagnóstico e intervencionismo cardiovascular han incrementado de manera significativa, hecho que genera mayor exposición a dosis bajas de radiación ionizante debido a la radiación dispersa por el paciente. El cristalino es una de las estructuras más sensibles a la radiación y las cataratas son la enfermedad ocular más estudiada y frecuente en el personal de la salud ocupacionalmente expuesto a dosis bajas de radiación. La formación de cataratas es un proceso multifactorial y la exposición a la radiación ionizante se ha asociado a opacidades subcapsulares posteriores, que es la forma más común de lesión, seguida por las cataratas corticales. Existen varios estudios que han evaluado los efectos de la exposición ocupacional por radiación ionizante en el cristalino en cardiólogos intervencionistas, comparándolos con controles no expuestos. Concluyen que hay mayor prevalencia de opacidades subcapsulares posteriores en el personal expuesto a radiación ionizante, especialmente en los cardiólogos intervencionistas (por trabajar muy cerca del generador de rayos X), las cuales están relacionadas con la duración de la práctica del intervencionismo cardíaco y disminuyen con el uso regular de los lentes plomados. Lo llamativo de muchos estudios es el bajo uso por parte de los cardiólogos intervencionistas de los elementos de protección radiológica, especialmente gafas y mampara plomada, las cuales han demostrado efectividad en la reducción de la radiación ionizante recibida por el personal de la sala de cateterismo cardiaco.

As the number and complexity of diagnostic and cardiovascular intervention procedures has increased significantly, this has led to a greater exposure to low doses of ionising radiation due to the radiation dispersal by the patient. The crystalline lens is one of the structures most sensitive to radiation, and cataracts are the most studied eye disease, and are common in health staff occupationally exposed to low radiation doses. The formation of cataracts is a process involving many factors, and exposure to ionising radiation has been associated with posterior sub-capsular opacities, the most common form of the injury, followed by cortical cataracts. There are several studies that have evaluated the effects of occupational exposure due to ionising radiation in the crystalline lens in interventionist cardiologists, and comparing them with non-exposed controls. They conclude that there is a higher prevalence of posterior sub-capsular opacities in personnel exposed to ionising radiation, especially in interventionist cardiologists (due to working very near the X-ray generator). These are associated with the duration of the practice of cardiac interventions, and decrease with the regular use of leaded glasses. The low use of radiation protection wear by interventionist cardiologists is highlighted in many studies, especially glasses and a leaded screen, which have shown to be effective in the reduction in the ionising radiation by the staff in the cardiac catheterisation room.

Ganoderic acid A protects lens epithelial cells from UVB irradiation and delays lens opacity / 中国天然药物

A contributory role of oxidative stress and protection by antioxidant nutrients have been suspected in cataract formation. Ganoderic acid A (GAA), an effective lanostane triterpene, is widely reported as an antioxidant. The aim of this study is to investigate the potential effects of GAA on cataract formation. After lens epithelial cells (LECs) were exposed to UVB radiation for different periods, cell viability, apoptosis-related protein levels, malondialdehyde (MDA) and superoxide dismutase (SOD) activities were monitored. We found that cell viability, the Bcl-2/Bax ratio and SOD activity were increased, while Cleaved caspase-3 levels and MDA activity were decreased compared with those in UVB-impaired LECs after GAA treated. Furthermore, GAA activated PI3K/AKT in UVB-impaired LECs and effectively delayed the occurrence of lens opacity in vitro. In conclusion, these findings demonstrated that GAA exhibited protective functions in SRA01/04 cells and rat lenses against UVB-evoked impairment through elevating cell viability and antioxidant activity, inhibiting cell apoptosis, activating the PI3K/AKT pathway and delaying lens opacity.

Prevalence of Lens Opacity in Interventional Cardiologists and Professional Working in the Hemodynamics in Brazil / Prevalência de Opacidades do Cristalino em Cardiologistas Intervencionistas e Profissionais Atuantes na Área de Hemodinâmica no Brasil

Abstract Background: Posterior subcapsular cataract is a tissue reaction commonly found among professionals exposed to ionizing radiation. Objective: To assess the prevalence of cataract in professionals working in hemodynamics in Brazil. Methods: Professionals exposed to ionizing radiation (group 1, G1) underwent slit lamp examination with a biomicroscope for lens examination and compared with non-exposed subjects (group 2, G2). Ophthalmologic findings were described and classified by opacity degree and localization using the Lens Opacities Classification System III. Both groups answered a questionnaire on work and health conditions to investigate the presence of risk factors for cataract. The level of significance was set at 5% (p < 0.05). Results: A total of 112 volunteers of G1, mean age of 44.95 (±10.23) years, and 88 volunteers of G2, mean age of 48.07 (±12.18) years were evaluated; 75.2% of G1 and 85.2% of G2 were physicians. Statistical analysis between G1 and G2 showed a prevalence of posterior subcapsular cataract of 13% and 2% in G1 and G2, respectively (0.0081). Considering physicians only, 38% of G1 and 15% of G2 had cataract, with the prevalence of posterior subcapsular cataract of 13% and 3%, respectively (p = 0.0176). Among non-physicians, no difference was found in the prevalence of cataract (by types). Conclusions: Cataract was more prevalent in professionals exposed to ionizing radiation, with posterior subcapsular cataract the most frequent finding.

Resumo Fundamento: A catarata subcapsular posterior é uma reação tecidual encontrada com frequência nos profissionais expostos à radiação ionizante. Objetivo: Avaliar a prevalência de catarata nos profissionais que atuam na área de hemodinâmica no Brasil. Métodos: Profissionais expostos à radiação ionizante (grupo 1, G1) foram submetidos ao exame biomicroscópico com lâmpada de fenda para avaliação do cristalino, e comparados aos não expostos (grupo 2, G2). Os achados foram descritos e classificados quanto ao grau de opacidade e localização por meio do Lens opacities classification system III. Ambos os grupos responderam questionário sobre condições de trabalho e de saúde para afastar fatores de risco para catarata, e foram comparados quanto aos achados. Foi utilizado um nível de significância de 5% (p < 0,05). Resultados: Foram avaliados 112 voluntários (G1) com média de idade 44,95 (±10,23) anos e 88 voluntários (G2) com média de 48,07 (±12,18) anos. Desses, 75,2% (G1) e 85,2% (G2) eram médicos. A análise estatística entre os grupos G1 e G2 mostrou uma prevalência da catarata no grupo G1 de 33% comparada ao G2 de 16% (p = 0,0058), sendo a catarata subcapsular posterior presente em 13% no G1 e 2% no G2 (p = 0,0081). Considerando apenas os médicos, 38% no G1 e 15% no G2 (p = 0,0011) apresentaram catarata, sendo a subcapsular posterior 13% e 3% (p = 0,0176), respectivamente. No grupo dos profissionais não médicos, não houve diferença estatisticamente significativa na prevalência dos achados oftalmológicos. Conclusões: A catarata esteve mais presente no grupo de profissionais expostos à radiação ionizante, sendo que a catarata subcapsular posterior foi o dano tecidual mais encontrado.

Effect of infrared radiation on the lens.

Background: Infrared (IR) radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim: The present study was designed to investigate the effect of IR radiation on rabbit’s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na+-K+ ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na+-K+ ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

Resultados estatísticos da monitorizaçäo individual externa em setores da área médica no ano de 1995 / Statistics results of external individual monitoring in sectors of medical area in 1995

Este trabalho analisa os resultados da monitoração individual externa de trabalhadores da área médica enfocando os níveis de dose em diferentes departamentos de diferentes hospitais.

Determinaçäo, pelo método da dosimetria termoluminescente, das doses de radiaçäo incidentes em órgäos críticos durante a obtençäo de radiografias extra-bucais: 2ª parte / Determination of the incidence of radiations in critical organs by the dosimetric thermoluminescent during the extra-oral radiographies: 2ª part

Dada a grande importância do exame radiográfico como complemento no diagnóstico, e sabendo dos efeitos biológicos dos raios X, muitos estudos têm sido realizados para a determinaçäo das doses de radiaçäo que atingem o organismo humano. Neste trabalho nos preocupamos com algumas técnicas extra-bucais como as de Waters, Granger e Shuller e as doses que atingem as gônadas, glândula tireóide e o cristalino na aplicaçäo de cada uma dessas técnicas. Estabeleceu-se comparaçöes sobre os métodos utilizados (filmes dosimétricos e dosímetros termoluminescentes de fluoreto de lítio - Lif 700), os tipos morfológicos estudados com a finalidade de encontrar meios para diminuir os índices de radiaçäo (fatores elétricos, filtraçäo e filmes) nos órgäos críticos citados

Quantificação da radiação incidente em órgãos críticos em crianças com dentição mista - (estudo comparativo entre as técnicas radiográficas oclusal e periapical) / Quantification of incident radiation on critical organs in children with mixed dentition: comparative study between occlusal and periapical radiographical techniques

O presente trabalho visa quantificar a radiação que incide em órgãos considerados críticos (tireóide, gônadas, cristalinos e pele), durante a tomada de radiografias intra-bucais pelas técnicas periapical da bissetriz e oclusal. Como dosímetros foram utilizados os termoluminescentes de fluoreto de lítio - 700. Os autores constataram que as maiores dosagens nos órgãos críticos foram: 0,101 rad para a tireóide na incidência oclusal inferior; 0,007 rad para as gônadas em ambas as técnicas; 0,268 rad no cristalino para a tomada periapical para molares superiores e 0,415 rad para a pele, em média

Efeito da radiaçäo gama nas proteínas de cristalino bovino in vitro / Effect of gama irradiation on in vitro bovine lens proteins

A radiossensibilidade das lentes oculares manifestada pela formaçäo de cataratas, tem sido de considerável interesse para pesquisadores no estudo dos efeitos biológicos das radiaçöes. A formaçäo da catarata se dá por diferentemente causas, e também pelo processo normal de envelhecimento. Neste trabalho o objetivo é desenvolver um sistema "on vitro", análogo à formaçäo da catarata. É usada uma soluçäo aquosa de cristalino bovino. Os cristalinos após remoçäo cirúrgica säo homogeneizados mecânicamente e por ultrasom. Está suspensäo é centrifugada e o sobrenadante é dializado e irradiado com diferentes doses de 60Co. A leitura do grau de opacificaçäo é feita por espectrofotometria.