A standardized Hippophae extract (SBL-1) counters neuronal tissue injuries and changes in neurotransmitters: implications in radiation protection.

CONTEXT: Effects of a radioprotective, standardized leaf extract (code SBL-1) from traditional medicinal plant, sea buckthorn [Hippophae rhamnoides L. (Elaeagnaceae)], on neurotransmitters and brain injuries in rats showing radiation-induced conditioned taste aversion (CTA), are not known. Understanding CTA in rats is important because its process is considered parallel to nausea and vomiting in humans. OBJECTIVE: This study investigated the levels of neurotransmitters, antioxidant defences and histological changes in rats showing radiation CTA, and their modification by SBL-1. MATERIALS AND METHODS: The inbred male Sprague-Dawley rats (age 65 days, weighing 190 ± 10 g) were used. Saccharin-preferring rats were selected using standard procedure and divided into groups. Group I (untreated control) was administered sterile water, group II was 60Co-γ-irradiated (2 Gy), and group III was administered SBL-1 before irradiation. Observations were recorded up to day 5. RESULTS: Irradiation (2 Gy) caused (i) non-recoverable CTA (≥ 64.7 ± 5.0%); (ii) degenerative changes in cerebral cortex, amygdala and hippocampus; (iii) increases in brain dopamine (DA, 63.4%), norepinephrine (NE, 157%), epinephrine (E, 233%), plasma NE (103%) and E (160%); and (iv) decreases in brain superoxide dismutase (67%), catalase (60%) and glutathione (51%). SBL-1 treatment (12 mg/kg body weight) 30 min before irradiation (i) countered brain injuries, (ii) reduced CTA (38.7 ± 3.0%, day 1) and (iii) normalized brain DA, NE, E, superoxide dismutase, catalase and CTA from day 3 onwards. DISCUSSION AND CONCLUSION: Radiation CTA was coupled with brain injuries, disturbances in neurotransmitters and antioxidant defences. SBL-1 pretreatment countered these disturbances, indicating neuroprotective action.

Avaliação sobre o conhecimento dos cirurgiões-dentistas de Montes Claros-MG sobre técnicas radiográficas, medidas de radioproteção e de biossegurança / Evaluation of the level of knowledge of dental surgeons regarding radiographic techniques, radioprotection measures, and biosafety in Montes Claros, MG Brazil

Objetivo: avaliar o grau de conhecimento dos cirurgiões-dentistas do município de Montes Claros, Minas Gerais, sobre a solicitação de exames radiográficos, medidas de radioproteção e de biossegurança. Materiais e Métodos: 203 cirurgiões-dentistas foram convidados a responder um questionário com 25 perguntas sobre os temas estudados. Dos 112 profissionais que o responderam, 41 eram clínicos gerais e 71 eram especialistas. Daquele total, 8 tinham menos de 5 anos de formado, 54, entre 5 a 15 anos e os últimos 50, mais de 15 anos. Os dados foram analisados por meio dos testes estatísticos Qui-Quadrado e Exato de Fisher, adotando-se o nível de significância de 5%. Resultados: Quanto à indicação de técnicas radiográficas para o diagnóstico de alterações bucais, 80,0% dos profissionais indicaram a radiografia interproximal para o diagnóstico da doença cárie. Quanto à radiografia periapical; 86,7% dos dentistas afirmaram indicá-la para quadros de doença periodontal; 88,8%, para tratamento endodôntico; 72,6% para extração de inclusos e 81,5%, para fraturas dentárias. Para o planejamento de implantes, 16,9% dos entrevistados indicaram a tomografia computadorizada e 52,3% recomendaram a radiografia panorâmica. Quanto à radioproteção e à biossegurança, 84,0% dos profissionais relataram a adoção do tempo de exposição elevado, acima de 0,8 segundos; 58,9% manifestaram ter preferência na realização do processamento pelo método manual inspecional; 52,7% afirmaram utilizar o acionamento dos raios-X pelo botão de retardo; e 84,8%, descartar os resíduos do revelador e fixador no esgoto comum. Percebeu-se uma correlação entre o tempo de formado e as seguintes condutas adotadas pelos profissionais...

Radioterapia y citoprotección. Mecanismo de acción. Bases

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Comparison of anti-fading agents used in fluorescence microscopy: image analysis and laser confocal microscopy study.

To ascertain the ability of commercial and home-made anti-fading media to reduce the decrease of fluorescein isothiocyanate (FITC) fluorescence, we studied the bleaching characteristics of FITC-stained Reh 6 cells mounted in buffered glycerol and in anti-fading media. We measured the intensity of fluorescence over time with a confocal laser scanning microscope and a standard epifluorescence microscope coupled to an image analysis system. Most of the anti-fading media effectively retard fading but each has drawbacks. Better results were obtained with media containing p-phenylenediamine (solutions in buffered glycerol, Vectashield, Fluorstop). However, Mowiol, Slowfade, n-propyl gallate (20 g/liter) were also effective in retarding fading. Most of them, except Mowiol, reduced fluorescence intensity. We concluded that the choice of anti-fading medium would depend on the desired results: a slower decay of fluorescence despite an initial quenching of fluorescence or a lower retardant effect with no decrease in initial fluorescence intensity. Moreover, the combination of Mowiol with another anti-fading medium may be a useful compromise when a strong retardant effect is required without marked quenching of the initial fluorescence.

Efectos lesivos potenciales de la luz de polimerización sobre el órgano de la visión / Injurious potential effects of the polimerization light on the sight organ

Debido a la nocividad de la luz ultravioleta sobre la piel y la visión, las resinas compuestas polimerizables por luz ultravioleta se utilizaron, desde el principio, con cierta precaución hacia los posibles efectos secundarios e incluso muchos odontólogos no consideraban segura su utilización. Por ello las resinas polimerizables por luz halógena tuvieron gran aceptación, porque el mismo nombre con que se designa, luz visible, lleva implícita la ausencia de riesgos, ya que nadie pensaría ni por un momento que la luz visible pudiese ser perjudicial. En esta revisión bibliográfica se presenta la anatomía ocular, la naturaleza de la luz, la fisiología de la visión, efectos de la luz de polimerización sobre ésta y las distintas propuestas que existen para la protección ocular, lo mismo que los antecedentes de la investigación sobre el daño ocular. Con esto se busca dar un campanazo de alerta para que a los conocidos riesgos del consultorio como los rayos X, el mercurio, las malas posiciones del operador, no se sume el daño ocular por un uso indebido de las lámparas de luz halógena y se prevenga esto, tanto para el operador como para el paciente

Efficiency of respirator canisters with methyl bromide.

Two kinds of respirator canisters, an organic vapor (OV) canister containing activated carbon and a methyl bromide (MB) canister containing activated carbon impregnated with triethylenediamine were investigated for their filtration efficiency of MB gas under various conditions of MB concentration, humidity and temperature. At lower MB concentrations, the breakthrough time of the OV canister was shorter than that of the MB canister. It also decreased with an increase in temperature, whereas the breakthrough time of the MB canister did not change with temperature. Humidity affected the breakthrough times of the OV canister as much as those of the MB canister. The desorption and the remaining filtration efficiency of MB gas were examined in both canisters which had been used for fumigation in plant quarantine. More than 5 ppm of MB gas leaked from 11 out of 18 used OV canisters, whereas less than 0.1 ppm MB leaked out from each of the used MB canisters. The mean remaining breakthrough time of the used OV canisters was 9.3 min, whereas that of the used MB canisters was 74.4 min. From the present study, it was shown that the gas masks with the OV canisters were not suitable for fumigating with MB gas.