ABSTRACT Several molecules and events involved in cell response to radiation-induced damage have been investigated towards a personalized radiotherapy. Considering the importance of active caspase-3 in the proteolytic cascade that ensures radiation-induced apoptosis execution, this research was designed to evaluate the expression levels of this protein as a bioindicator of individual radiosensitivity. Peripheral blood samples of 10 healthy individuals were gamma-irradiated (cobalt-60 source) with 1, 2 and 4 Gy (control: non-irradiated samples), and active caspase-3 expression levels were measured in lymphocytes, by flow cytometry, ex vivo and after different times of in vitro incubation (24, 48 and 72 hours). Short-term incubation of 24 h was the most adequate condition to evidence correlations between dose radiation and active caspase-3 expression. For each radiation dose, it was observed a significant inter-individual variation in active caspase-3 expression intensity, suggesting that this parameter may be suitable for evidence individual radiosensitivity. The methodology presented and discussed in this work may help to predict healthy tissues response to radiation exposure toward the better patient outcome.

RESUMO Este trabalho avaliou os efeitos da radiação ionizante sobre as características físico-químicas e sensoriais de batata inglesa da cultivar Ágata (Solanum tuberosum L.), incluindo brotamento e a deterioração, com o objetivo final de aumentar a vida de prateleira. Para isso, quatro grupos de amostras foram colhidos na fase de maturação. Três destes grupos foram separadamente expostos a uma fonte de Co-60, recebendo respectivas doses de 0,10, 0,15 e 2,00 kGy, enquanto que o grupo não irradiado foi mantido como controle. Todas as amostras foram armazenadas durante 35 dias a 24 ° C (± 2) e a 39% de umidade relativa. Os seguintes aspectos foram avaliados: brotamento, podridão, perda de peso, textura, cor da polpa, umidade, aparência externa e interna, aroma, teor de sólidos solúveis, acidez titulável, vitamina C, proteínas, amido e glicose. Os resultados indicaram que a dose de 0,15 kGy foi a mais eficaz para reduzir a germinação e perdas pós-colheita, sob as condições estudadas.

ABSTRACT This work evaluated the effects of ionizing radiation on the physico-chemical and sensory characteristics of the potato cultivar Ágata (Solanum tuberosum L.), including budding and deterioration, with the end goal of increasing shelf life. For this, four groups of samples were harvested at the maturation stage. Three of them were separately exposed to a Co-60 source, receiving respective doses of 0.10, 0.15 and 2.00 kGy, while the non-irradiated group was kept as a control. All samples were stored for 35 days at 24 °C (± 2) and at 39% relative humidity. The following aspects were evaluated: budding, rot, loss of weight, texture, flesh color, moisture, external and internal appearance, aroma, soluble solids, titratable acidity, vitamin C, protein, starch and glucose. The results indicated that 0.15 kGy was the most effective dose to reduce sprouting and post-harvest losses, under the conditions studied.

O objetivo deste trabalho foi avaliar a relação entre os níveis da proteína p53 e as doses absorvidas a partir de linfócitos humanos irradiados in vitro. Para isto, amostras de sangue de 23 doadores foram irradiadas com 0,5; 1; 2; e 4 Gy a partir de uma fonte de cobalto-60, e as porcentagens de linfócitos expressando p53 foram quantificadas por Citometria de Fluxo. Os indivíduos foram divididos em três grupos, de acordo com os níveis da p53 expressos por dose de radiação: baixo (Grupo I), elevado (Grupo II), e níveis excessivos (Grupo III). Para todos os grupos, as análises mostraram que os níveis de expressão da p53 aumentam com a dose absorvida. Particularmente para os grupos I e II, a correlação entre a expressão desta proteína e a dose segue o modelo linear-quadrático, como para as aberrações cromossômicas radioinduzidas. Em conclusão, nossos achados indicam possíveis aplicações desta metodologia na avaliação radiossensibilidade individual antes de procedimentos radioterapêuticos, bem como na monitoração médica de trabalhadores ocupacionalmente expostos. Além disso, devido à rapidez das análises por Citometria de Fluxo, a metodologia aqui empregada poderá desempenhar um papel importante nas ações emergenciais em incidentes radioativos de larga escala, onde muitas pessoas podem ter sido expostas.

The aim of this research was to evaluate the relationship between p53 protein levels and absorbed doses from in vitro irradiated human lymphocytes. For this, samples of blood from 23 donors were irradiated with 0.5; 1; 2; and 4 Gy from a Cobalt-60 source, and the percentages of lymphocytes expressing p53 were scored using Flow Cytometry. The subjects were divided into 3 groups, in accordance with the p53 levels expressed per radiation dose: low (Group I), high (Group II), and excessive levels (Group III). For all groups, the analyses showed that the p53 expression levels increase with the absorbed dose. Particularly for groups I and II, the correlation between this protein expression and the dose follows the linear-quadratic model, such as for radioinduced chromosomal aberrations. In conclusion, our findings indicate possible applications of this approach in evaluating individual radiosensitivity prior to radiotherapeutical procedures as well as in medical surveillance of occupationally exposed workers. Furthermore, due to the rapidity of flow-cytometric analyses, the methodology here employed would play an important role in emergency responses to a large-scale radiation incident where many people may have been exposed.

Anacardium occidentale L. Anacardiaceae, known as cashew, commonly found in northeastern of Brazil, has high levels of secondary metabolites, particularly tannins, used as raw material for herbal medicines. An efficient alternative to decontaminate plant products is the total sterilization or reduction of the initial microbial count, the process of gamma irradiation with 60Co. The objective of this study was to analyze the antimicrobial activity of crude extracts of bark and leaves of A. occidentale, based on the quantification of total phenols and tannins, before and after exposure to gamma radiation from 60Co. The extracts were obtained in the laboratory by cold maceration in ethanol, filtered and dryness. They were divided into non-irradiated control group (0 kGy) and irradiated: groups exposed to gamma radiation at doses of 5, 7.5 and 10 kGy. The total phenols was obtained by the Folin-Ciocalteau method and tannins, by the precipitation of casein. The antimicrobial potential activities of these extracts were also evaluated. The results showed that gamma radiation doses employed in this study did not influence statistically the percentage of total phenols and tannins in the bark extracts, at levels ranging from 5.73±0.14 and 5.20±0.14, respectively. The levels of metabolites in the leaves were statistically (p<0.05) influenced by radiation, observed average total phenols between 3.13±0.04 (0 kGy) and 3.50±0.08 (10 kGy), and tannin between 2.47±0.06 (0 kGy) and 2.93±0.04 (10 kGy). The extracts of bark and leaves were active against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Enterococcus faecalis, Mycobacterium smegmatis, Candida albicans. Gamma radiation caused an increase in antimicrobial activity of extracts against Staphylococcus aureus (Gram positive), with average inhibition zones for shells: 14.33±058 (0 kGy) and 22.33±0.58 (10 kGy), and leaves: 11.33±0.58 (0 kGy) and 19.00±1.00 (10 kGy). Exposure to radiation caused changes in physical and chemical constituents of phenolic extracts of leaves of cashew, increasing levels of tannins.