This exploratory and cross-sectional study aimed to identify the prevalence of bullying in a group of students and analyze the data regarding the gender of those involved in the violence. A questionnaire adapted from Olweus was applied in seven elementary education schools in Portugal. The sample consisted of 387 students between 7 and 14 years old. Data are presented in terms of descriptive statistics and differences between proportions were analyzed using chi-square tests. The gender analysis of victimization and aggression shows that boys and girls are both victims and aggressors, and there are significant differences in involvement in bullying between genders and the roles played. Boys are victims more often when considering different types of bullying, although significant differences were only found for physical aggression. Strategies that include gender roles are a priority for prevention and careful attention to this phenomenon in the school context. The questions addressed contribute to a broader understanding of the phenomenon, emphasizing the differential participation of boys and girls in bullying.

A atividade física é um comportamento importante na promoção de saúde e na prevenção de doenças. Para que se desenvolvam programas eficazes no incentivo à prática de atividade física em adolescentes, torna-se necessário que se identifiquem os fatores que a determinam. Este estudo pretende rever alguns dos aspectos do estado atual do conhecimento acerca da influência de determinantes demográfico-biológicos (idade, sexo, estatuto sócio-econômico) e sócio-culturais (família, pares e professor de educação física) na atividade física de adolescentes. Nesta revisão apenas foram incluídos estudos efetuados com amostras superiores a 100 adolescentes com idades entre os 10 e os 18 anos, que tenham adotado delineamentos de pesquisa transversal e que tenham utilizado questionários. Os principais resultados e conclusões foram que: a idade parece estar negativamente associada à atividade física; o sexo masculino tende a estar mais envolvido nessas atividades; o estatuto sócio-econômico elevado parece ser um fator protetor do risco de inatividade física; a participação da família e dos pares em atividades físicas parece estar positivamente associada às atividades por parte dos adolescentes; o professor de educação física parece não representar um fator propiciador da atividade física.

Background Oxidative stress is one of the most important components of the ischemia-reperfusion process after kidney transplantation (KTx) and increases with graft dysfunction. Methods This prospective study was conducted on 40 consecutive KTx recipients to evaluate time-dependent changes in oxidative stress-related parameters within the first week after KTx and to assess their performance in predicting delayed graft function (DGF=dialysis requirement during initial posttransplant week) and graft function at 1 year. Blood samples were collected before (day 0) and after KTx (days 1, 2, 4, and 7). Total antioxidant capacity, plasma levels of malondialdehyde (MDA), and activities of glutathione peroxidase, glutathione reductase and superoxide dismutase were measured. Multivariable linear mixed and linear regression models, receiver-operating characteristic (ROC), and areas under ROC curves (AUC-ROC) were used. Results At all time points after KTx, mean MDA levels were significantly higher in patients developing DGF (n=18). Shortly after KTx (8–12 hr), MDA values were higher in DGF recipients (on average, +0.16 μmol/L) and increased further on following day, contrasting with prompt functioning recipients. Day 1 MDA levels accurately predicted DGF (AUC-ROC=0.90), with a performance higher than SCr (AUC-ROC=0.73) and similar to cystatin C (AUC-ROC=0.91). Multivariable analysis revealed that MDA levels on day 7 represented an independent predictor of 1-year graft function. Antioxidant enzyme activities were not significantly changed during the study period and were not predictors of 1-year graft function. Conclusions Increased MDA levels on day 1 after KTx might be an early prognostic indicator of DGF, and levels on day 7 might represent a useful predictor of 1-year graft function.

Gene expression can be silenced by proximity to heterochromatin blocks containing centromeric α-satellite DNA. This has been shown experimentally through cis-acting chromosome rearrangements resulting in linear genomic proximity, or throughtrans-acting changes resulting in intranuclear spatial proximity. Although it has long been been established that centromeres are nonrandomly distributed during interphase, little is known of what determines the three-dimensional organization of these silencing domains in the nucleus. Here, we propose a model that predicts the intranuclear positioning of centromeric heterochromatin for each individual chromosome. With the use of fluorescence in situ hybridization and confocal microscopy, we show that the distribution of centromeric α-satellite DNA in human lymphoid cells synchronized at G₀/G₁is unique for most individual chromosomes. Regression analysis reveals a tight correlation between nuclear distribution of centromeric α-satellite DNA and the presence of G-dark bands in the corresponding chromosome. Centromeres surrounded by G-dark bands are preferentially located at the nuclear periphery, whereas centromeres of chromosomes with a lower content of G-dark bands tend to be localized at the nucleolus. Consistent with the model, a t(11; 14) translocation that removes G-dark bands from chromosome 11 causes a repositioning of the centromere, which becomes less frequently localized at the nuclear periphery and more frequently associated with the nucleolus. The data suggest that “chromosomal environment” plays a key role in the intranuclear organization of centromeric heterochromatin. Our model further predicts that facultative heterochromatinization of distinct genomic regions may contribute to cell-type specific patterns of centromere localization.