Effect of luting cement thickness on the bond strength of glass fiber posts to dentin.

The objective of this study was to evaluate the effect of cement thickness and luting cement type on the push-out bond strength of glass fiber posts (GFPs) to root dentin. Sixty human maxillary root-filled canines or premolars with single straight roots were randomly divided into 6 groups (n = 10) according to the GFP configuration (conventional or relined with composite resin) and the cement used (RelyX U200, Ketac Cem, or Allcem Core). After endodontic treatment and GFP cementation, all of the roots were sectioned perpendicular to their long axis to obtain 1.0-mm-thick slices (n = 6 per group), which were mounted on a universal testing machine and submitted to a push-out test. The data (n = 45 to 51 specimens per group because of pretest failures) were analyzed by means of 2-way analysis of variance (ANOVA) and Tukey tests (α = 0.05). The type of failure was determined under a stereomicroscope, and representative specimens were observed with scanning electron microscopy. Significant interactions between the cements and GFP configurations were detected in the coronal and apical thirds (P < 0.05; 2-way ANOVA). For the coronal third, both RelyX U200 cement groups exhibited the greatest push-out bond strengths but were not significantly different from the Allcem Core relined group. For the middle third, no statistically significant interactions were observed between the cements and GFP configurations (P = 0.232; 2-way ANOVA). Adhesive failure between the dentin and cement layer was the most frequently observed failure mode. As expected, because of the composite resin added to relined GFPs, the cement layer was thinner in those groups. The type of cement used played an important role in the push-out bond strength.

Human health risk assessment and geochemical mobility of rare earth elements in Amazon soils.

Rare earth elements (REEs) are a grouping of elements that encompasses lanthanides, yttrium and scandium due to their similar chemical properties and occurrence in ore deposits. Over the past few decades, economic interest in REEs has increased due to their use in several types of industries such as high-tech, medicine and agriculture. Extraction of REEs has been followed, in general, by incorrect disposal of tailing and waste, creating hazardous conditions in several countries. However, the magnitude of the possible impacts on ecosystem and human health are relatively unknown, especially in tropical systems. Thus, the objectives of this study were to assess the geochemical mobility and the bioaccessibility of REEs based on a series of chemical extractions and in vitro essay. We also tested two promising simple protocols (0.01 mol L-1 CaCl2 and 0.43 mol L-1 HNO3) for measuring REE bioaccessible fractions through a single extraction. Our findings show that the bioavailable fractions represent less than 20% of the ΣREEs fraction in all soil samples examine. Similarly, the oral bioaccessibility obtained by two in vitro methods (Gastric protocol and Gastric-Intestinal protocol) and by the single extraction tests represented less than 20% of the ΣREE contents. The non-carcinogenic risks and the carcinogenic risks associated to REEs oral exposure were low for children and adults. The extractions with 0.01 mol L-1 CaCl2 showed great potential as a method for measuring the REEs bioaccessible fraction.

Low-level lead exposure changes endothelial modulation in rat resistance pulmonary arteries.

Lead exposure induces hypertension and endothelial dysfunction. However, the effects on the pulmonary vasculature have not been explored. In this study, rats exposed to lead acetate for seven days (4µg/100g on the 1st day and 0.05µg/100g/day i.m. subsequently) had lead blood level of 3.9±0.7µg/dL and increased right ventricular pressures. There was an increased Pb deposition and superoxide anions production in the pulmonary arteries, associated with reduced vasoconstriction but unchanged endothelium-dependent vasodilatation to acetylcholine (ACh). In both groups, inhibition of the nitric oxide (NO) synthase with L-NAME blocked the response to ACh, while indomethacin (cycloxygenase inhibitor) had no effect. Incubation with nonspecific potassium channel blocker (tetraethylammonium) reduced the ACh-induced vasodilatation only in the Pb group. Apamin (SKCa channel blocker) and 4-aminopyridine (Kv channel blocker), but not iberiotoxin (BKCa channel blocker), also inhibited this response in the Pb group. The vasodilatation to exogenous NO was reduced by Pb, while relaxation to the cGMP analogue was similar between groups. Concordantly, the protein level of soluble guanylate cyclase (sGC) was reduced. In conclusion, short-term and low-level exposure to Pb changes pulmonary haemodynamic and increases oxidative stress. The pulmonary vasculature exhibited increased hyperpolarization by the Kv and SKCa channels, probably as a compensatory mechanism to the decreased responsiveness to NO.

Prevenção das doenças cardiovasculares nas pessoas em recuperação do uso de substâncias psicoativas / Prevention of cardiovascular disease in patients recovering from use of psychoactive substances

Objetivo: Avaliar o conhecimento das pessoas em recuperação do uso de substâncias psicoativas sobre os fatores de risco das doenças cardiovasculares após realização de atividade educativa. Métodos: Estudo quantitativo, realizado em hospital psiquiátrico público do Ceará, com amostra de 36 pessoas internadas na unidade de desintoxicação que concordaram em participar do estudo, maiores de 18 anos, orientadas e conscientes. Utilizou-se um formulário para coleta de dados sociodemográficos e aferir o grau de conhecimento sobre as doenças cardiovasculares e seus fatores de risco, antes e após a realização de atividades de educação em saúde. Resultados: Os resultados demonstraram que inicialmente, 19 (52,8%) pessoas afirmaram não conhecer nenhuma doença cardiovascular e depois da atividade esse número caiu para 4 (11%). Foi avaliada, ainda, a referência aos fatores de risco para doenças do aparelho circulatório, quando se constatou que, antes da atividade educativa, 22 (61%) desconheciam estes fatores, outros 14 (39%) citaram de um a dois, principalmente a alimentação rica em gorduras e o uso de drogas ilícitas, após a atividade apenas 3 (8%) desconheciam e os outros 33 (92%) passaram a citar uso de drogas lícitas, obesidade, sedentarismo. Conclusão: A atividade educativa ocasionou uma mudança significativa no conhecimento dos participantes acerca do tema explorado, o que poderá gerar melhora no estilo de vida do paciente e de sua família.

Objective: Assess the knowledge of people recovering from substance abuse, after performance of educational activities, about the risk factors of cardiovascular diseases. Methods: This was a quantitative study involving 36 patients receiving treatment in the detoxification unit of a public psychiatry hospital in the State of Ceará, Brazil. All subjects were consenting adults over the age of 18 years. A questionnaire was used before and after an educational activity that measured the level of knowledge and understanding of cardiovascular disease and related risk factors. Results: The results demonstrated that initially, 19 (52.8%) people confirmed that they were not aware of any cardiovascular disease but after the activity, this number dropped to 4 (11%). In addition, the reference to the risk factors for diseases of the circulatory system was evaluated, when it became evident that, before the educational activity, 22 (61%) did not know these factors, another 14 (39%) cited one or two, especially a diet rich in fat and the use of illegal drugs. After the activity only 3 (8%) did not know and the other 33 (92%) were able to cite the use of legal drugs, obesity, and a sedentary lifestyle. Conclusion: Educational intervention resulted in a significant change in participants´ knowledge of cardiovascular risk factors, which may help result in improvement in the lifestyle of patients, as well as their families.