49 resultados para antioxidants activity


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Context: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer. Objective: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation. Materials and methods: Physical, microbiological and functional stability were evaluated during 6 months storage at 20 °C and 40 °C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed. Results and discussion: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20 °C for 6 months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610 ± 70 µgh−0.5) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4 h after product’s application. Conclusion: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.

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Objective To examine the combined effects of physical activity and weight status on blood pressure (BP) in preschool-aged children. Study design The sample included 733 preschool-aged children (49% female). Physical activity was objectively assessed on 7 consecutive days by accelerometry. Children were categorized as sufficiently active if they met the recommendation of at least 60 minutes daily of moderate-to-vigorous physical activity (MVPA). Body mass index was used to categorize children as nonoverweight or overweight/obese, according to the International Obesity Task Force benchmarks. BP was measured using an automated BP monitor and categorized as elevated or normal using BP percentile-based cut-points for age, sex, and height. Results The prevalence of elevated systolic BP (SBP) and diastolic BP was 7.7% and 3.0%, respectively. The prevalence of overweight/obese was 32%, and about 15% of children did not accomplish the recommended 60 minutes of daily MVPA. After controlling for age and sex, overweight/obese children who did not meet the daily MVPA recommendation were 3 times more likely (OR 3.8; CI 1.6-8.6) to have elevated SBP than nonoverweight children who met the daily MVPA recommendation. Conclusions Overweight or obese preschool-aged children with insufficient levels of MVPA are at significantly greater risk for elevated SBP than their non overweight and sufficiently active counterparts. (J Pediatr 2015;167:98-102).

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Objective Public health organizations recommend that preschool-aged children accumulate at least 3 h of physical activity (PA) daily. Objective monitoring using pedometers offers an opportunity to measure preschooler's PA and assess compliance with this recommendation. The purpose of this study was to derive step-based recommendations consistent with the 3 h PA recommendation for preschool-aged children. Method The study sample comprised 916 preschool-aged children, aged 3 to 6 years (mean age = 5.0 ± 0.8 years). Children were recruited from kindergartens located in Portugal, between 2009 and 2013. Children wore an ActiGraph GT1M accelerometer that measured PA intensity and steps per day simultaneously over a 7-day monitoring period. Receiver operating characteristic (ROC) curve analysis was used to identify the daily step count threshold associated with meeting the daily 3 hour PA recommendation. Results A significant correlation was observed between minutes of total PA and steps per day (r = 0.76, p < 0.001). The optimal step count for ≥ 3 h of total PA was 9099 steps per day (sensitivity (90%) and specificity (66%)) with area under the ROC curve = 0.86 (95% CI: 0.84 to 0.88). Conclusion Preschool-aged children who accumulate less than 9000 steps per day may be considered Insufficiently Active.

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Introdução: A prática de atividade física tem vindo a ser incentivada por vários organismos nacionais e internacionais, visando a promoção de saúde. No entanto, não existe consenso em relação à influência e à intensidade ótima da atividade física durante a gravidez, tal facto pode dever-se à falta de instrumentos válidos que permitam a comparação entre os vários países do nível de atividade física das gestantes. Não foi identificado qualquer questionário válido que avaliasse a atividade física, durante a gravidez, para a população portuguesa. Objetivo: O objetivo deste estudo foi traduzir e adaptar o questionário PPAQ para a língua portuguesa e testar a fiabilidade e validade do mesmo. Métodos: A equivalência linguística foi obtida através da tradução e retrotradução e após a realização de um teste piloto a 6 mulheres grávidas. A fiabilidade foi obtida através do testereteste, com um intervalo de 7 dias, e analisada através do ICC, SEM e do método Bland Altman. A validade de critério foi testada, através dos resultados do PPAQ e do acelerómetro, pelo coeficiente de correlação de Pearson. Resultados: Os valores do ICC relativos à fiabilidade foram para o score total do PPAQ de 0,77, para as atividades sedentárias 0,87, para as atividade de baixa intensidade 0,76, para as atividades de intensidade moderada 0,76 e para as atividades de intensidade vigorosa 0,70. Na avaliação da validade obtivemos um valor de correlação de Pearson para atividade total de -0,030. Obtivemos correlação significante para as atividades de baixa intensidade (r=0,149; p=0,025), para as atividades de baixa intensidade em grávidas no 2º trimestre (r=0,256; p=0,010) e para as atividades de baixa intensidade e atividades vigorosas em mulheres no 3º trimestre gestacional (r=0,447; p=0,037 e r= 0,578; p=0,005, respetivamente). Conclusão: O PPAQ apresenta uma fiabilidade excelente e validade semelhante à versão original.