Efeitos de um programa prolongado de exercício na tolerância ao esforço de indivíduos com antecedentes de síndrome coronário agudo

Objectivos: Este estudo teve por objectivo verificar a influência de um programa prolongado de exercício físico em parâmetros de aptidão física e cardiovasculares avaliados em prova de esforço máximo, em sujeitos com diagnóstico recente de síndrome coronário agudo. Métodos: A amostra, constituída por 50 sujeitos, foi distribuída por um grupo experimental (n=25) e por um grupo controlo (n=25), tendo o grupo experimental ficado sujeito a um programa de exercício físico regular durante 52 semanas. Todos os indivíduos realizaram duas provas de esforço máximas (PEM) em tapete rolante, uma no início e a outra no final do protocolo experimental, tendo a primeira prova sido realizada 2-3 meses após o evento cardíaco. Nas PEM foram registados parâmetros de aptidão física (velocidade máxima, inclinação máxima do tapete e tempo de prova), dos indicadores metabólicos (METs máximo) e parâmetros cardiovasculares (frequência cardíaca repouso e máxima durante a prova, tensão arterial de repouso e máxima durante a prova e o duplo produto máximo e em repouso). Resultados: Comparativamente à primeira prova, na segunda PEM verificou-se no grupo experimental um aumento significativo (p<0,05) dos valores absolutos dos indicadores de aptidão física, com uma percentagem de variação destes parâmetros significativamente superior à do grupo controlo. No entanto, apesar do melhor desempenho físico evidenciado pelo grupo experimental, não se verificaram diferenças significativas entre os dois grupos no que respeita aos parâmetros cardiovasculares. Conclusão: Os resultados permitem concluir que o programa de exercícios se revelou vantajoso para os indivíduos do grupo experimental, tendo-lhes aumentado a tolerância ao esforço físico máximo sem uma aparente sobrecarga cardiovascular adicional.

Young people's blood alcohol concentration and the alcohol consumption city law, Brazil

The paper assesses blood alcohol concentration and risk behaviors for traffic accidents before and after the implementation of a law which prohibits the use of alcoholic beverages on city gas stations. In Porto Alegre, Southern Brazil, young people go out at night and drive to gas station convenience stores to buy alcoholic beverages which are consumed on the premises of parking lots in gas stations. Data were obtained from self-administered questionnaires and breath analyzers in two cross-sectional collections with purposive samples of youngsters in May and July 2006 (n=62, and n=50, respectively). There were no significant differences between the groups before and after the city law was passed. Blood alcohol concentration greater than 0.06% was found in 35.5% of pre-law group and 40% of post-law group (p=0.62). Results point out heavy alcohol use in both groups, which did not change after the law was passed.

Desenvolvimento e procedimentos de validação de uma metodologia analítica por GC/MS/MS para a determinação de antidepressivos em sangue total

A depressão é uma das doenças de foro psiquiátrico que mais prevalece na nossa sociedade, subsistindo evidências epidemiológicas que indicam um aumento substancial da sua incidência nos últimos anos. Esta evidência é consubstanciada pelo aumento significativo do consumo de antidepressivos em Portugal. Este cenário pressupõe a necessidade de uma metodologia que permita analisar, com rigor e numa perspectiva de rotina, os antidepressivos que podem ser encontrados em amostras de sangue. No contexto do Serviço de Toxicologia Forense do Instituto Nacional de Medicina Legal, Delegação do Norte, torna-se necessário o desenvolvimento de uma metodologia analítica para a determinação simultânea de 15 antidepressivos em sangue total e a sua validação relativamente a vários parâmetros analíticos. Os antidepressivos considerados foram Amitriptilina, Citalopram, Clomipramina, N-Desmetilclomipramina, Dotiepina, Fluoxetina, Imipramina, Maprotilina, Mianserina, Mirtazapina, Nortriptilina, Paroxetina, Sertralina, Trimipramina e Venlafaxina. A técnica utilizada para este efeito foi o GC/MS/MS, aplicando um procedimento extractivo prévio apropriado, baseado em procedimentos convencionais de extracção em fase sólida. A escolha desta técnica teve por base a possibilidade de identificar inequivocamente os compostos presentes na amostra, independentemente da complexidade da matriz, e de originar metodologias com uma sensibilidade elevada e com limites de detecção muito baixos. Os parâmetros analíticos considerados para validação da metodologia estabelecida foram selectividade/especificidade e capacidade de identificação; limites de detecção e de quantificação; linearidade e gama de trabalho; eficiência de extracção; arrastamento; exactidão (precisão, veracidade e incerteza de medição) e robustez. Com excepção da exactidão, um parâmetro que carece ainda de estudos complementares, todos os parâmetros estudados foram validados de acordo com os requisitos internos do Serviço. De uma forma geral, os resultados obtidos com o método desenvolvido revelaram-se selectivos e apresentaram respostas analíticas tanto para concentrações de antidepressivos em níveis terapêuticos como para níveis letais destas drogas. Os procedimentos extractivos revelaram-se eficazes e não foram verificados fenómenos de arrastamento em concentrações mais elevadas. O método foi ainda considerado robusto.

Ressonância magnética funcional: mapeamento do córtex motor através do efeito BOLD

Introdução – A ressonância magnética funcional (RMf) é hoje uma ferramenta fundamental na investigação funcional do cérebro humano, quer em indivíduos saudáveis quer em doentes com patologias diversas. É uma técnica complexa que necessita de uma aplicação cuidada e rigorosa e uma compreensão dos mecanismos biofísicos, de modo a serem obtidos resultados fiáveis e com melhor aceitação clínica. O efeito BOLD (Blood Oxygenation Level Dependent), que se baseia nas propriedades magnéticas da hemoglobina, é o método mais utilizado para medir a atividade cerebral por RMf. Objetivos – Otimizar um protocolo de RMf por efeito BOLD em voluntários saudáveis para mapeamento do córtex motor, de modo a que possa ser aplicado no futuro em doentes com patologias diversas. Metodologia – Foram estudados 34 voluntários saudáveis divididos em 2 grupos de estudo: BOLD 1 e BOLD 2. Com vista à otimização, foram testados no subgrupo BOLD 1 diferentes paradigmas e no subgrupo BOLD 2 foi estudada a influência do tempo de eco (TE). Para as várias condições foram comparados os volumes da região ativada e os níveis de ativação obtidos. Resultados/Discussão – O córtex motor foi identificado em todos os voluntários estudados. Não foram detetadas diferenças estatisticamente significativas quando comparados os resultados obtidos com os diferentes parâmetros de aquisição. Conclusão – O protocolo foi otimizado tendo em conta o nível de conforto reportado pelos voluntários. Uma vez que se pretende aplicar este mesmo protocolo no estudo de doentes, este fator torna-se particularmente relevante.

The influence of the blood pressure on the venous cerebral flow measured by magnetic susceptibility (SWI) technique

Susceptibility Weighted Image (SWI) is a Magnetic Resonance Imaging (MRI) technique that combines high spatial resolution and sensitivity to provide magnetic susceptibility differences between tissues. It is extremely sensitive to venous blood due to its iron content of deoxyhemoglobin. The aim of this study was to evaluate, through the SWI technique, the differences in cerebral venous vasculature according to the variation of blood pressure values. 20 subjects divided in two groups (10 hypertensive and 10 normotensive patients) underwent a MRI system with a Siemens® scanner model Avanto of 1.5T using a synergy head coil (4 channels). The obtained sequences were T1w, T2w-FLAIR, T2* and SWI. The value of Contrast-to-Noise Ratio (CNR) was assessed in MinIP (Minimum Intensity Projection) and Magnitude images, through drawing free hand ROIs in venous structures: Superior Sagittal Sinus (SSS) Internal Cerebral Vein (ICV) and Sinus Confluence (SC). The obtained values were presented in descriptive statistics-quartiles and extremes diagrams. The results were compared between groups. CNR shown higher values for normotensive group in MinIP (108.89 ± 6.907) to ICV; (238.73 ± 18.556) to SC and (239.384 ± 52.303) to SSS. These values are bigger than images from Hypertensive group about 46 a.u. in average. Comparing the results of Magnitude and MinIP images, there were obtained lower CNR values for the hypertensive group. There were differences in the CNR values between both groups, being these values more expressive in the large vessels-SSS and SC. The SWI is a potential technique to evaluate and characterize the blood pressure variation in the studied vessels adding a physiological perspective to MRI and giving a new approach to the radiological vascular studies.

Diagnosis of iron deficiency anemia in children of Northeast Brazil

OBJECTIVE: To diagnose iron deficiency anemia in children. METHODS: The study was conducted with a sample of 301 children aged six to 30 months attending public daycare centers in the city of Recife, Northeast Brazil, in 2004. The diagnoses of anemia were based on a combination of different hematological and biochemical parameters: hemoglobin, mean corpuscular volume, ferritin, C-reactive protein, transferrin saturation and transferrin receptor. The chi-square test and ANOVA were used in the statistical analysis. RESULTS: Of all children studied, 92.4% had anemia (Hb <110 g/L) and 28.9% had moderate/severe anemia (Hb <90 g/L). Lower levels of hemoglobin were found in children aged 6-17 months. Iron deficiency was found in 51.5% of children using ferritin (<12 μg/L) as parameter. Taking into consideration the combination of hemoglobin level, ferritin and transferrin receptor, 58.1% had anemia with iron deficiency, 34.2% had anemia without iron deficiency and 2.3% had iron deficiency without anemia. Mean ferritin concentration was significantly higher in children with high C-reactive protein when compared with those with normal levels (22.1 vs. 14.8 µg/L). CONCLUSIONS: The use of several biochemical and hematological parameters allowed to diagnosing iron deficiency anemia in two thirds of children, suggesting a need to identify other determinants of anemia without iron deficiency.

The influence of count's number in myocardium in the determination of reproducible parameters in Gated-SPECT studies simulated with GATE

Myocardial Perfusion Gated Single Photon Emission Tomography (Gated-SPET) imaging is used for the combined evaluation of myocardial perfusion and left ventricular (LV). The purpose of this study is to evaluate the influence of the total number of counts acquired from myocardium, in the calculation of myocardial functional parameters using routine software procedures. Methods: Gated-SPET studies were simulated using Monte Carlo GATE package and NURBS phantom. Simulated data were reconstructed and processed using the commercial software package Quantitative Gated-SPECT. The Bland-Altman and Mann-Whitney-Wilcoxon tests were used to analyze the influence of the number of total counts in the calculation of LV myocardium functional parameters. Results: In studies simulated with 3MBq in the myocardium there were significant differences in the functional parameters: Left ventricular ejection fraction (LVEF), end-systolic volume (ESV), Motility and Thickness; between studies acquired with 15s/projection and 30s/projection. Simulations with 4.2MBq show significant differences in LVEF, end-diastolic volume (EDV) and Thickness. Meanwhile in the simulations with 5.4MBq and 8.4MBq the differences were statistically significant for Motility and Thickness. Conclusion: The total number of counts per simulation doesn't significantly interfere with the determination of Gated-SPET functional parameters using the administered average activity of 450MBq to 5.4MBq in myocardium.

Subacute effects of the thiodicarb pesticide on target organs of male wistar rats: biochemical, histological, and flow cytometry studies

Thiodicarb, a carbamate pesticide widely used on crops, may pose several environmental and health concerns. This study aimed to explore its toxicological profile on male rats using hematological, biochemical, histopathological, and flow cytometry markers. Exposed animals were dosed daily at 10, 20, or 40 mg/kg/body weight (group A, B, and C, respectively) during 30 d. No significant changes were observed in hematological parameters among all groups. After 10 d, a decrease of total cholesterol levels was noted in rats exposed to 40 mg/kg. Aspartate aminotransferase (AST) activity increased (group A at 20 d; groups A and B at 30 d) and alkaline phosphatase (ALP) (group B at 30 d) activity significantly reduced. At 30 d a decrease of some of the other evaluated parameters was observed with total cholesterol and urea levels in group A as well as total protein and creatinine levels in groups A and B. Histological results demonstrated multi-organ dose-related damage in thiodicarb-exposed animals, evidenced as hemorrhagic and diffuse vacuolation in hepatic tissue; renal histology showed disorganized glomeruli and tubular cell degeneration; spleen was ruptured with white pulp and clusters of iron deposits within red pulp; significant cellular loss was noted at the cortex of thymus; and degenerative changes were observed within testis. The histopathologic alterations were most prominent in the high-dose group. Concerning flow cytometry studies, an increase of lymphocyte number, especially T lymphocytes, was seen in blood samples from animals exposed to the highest dose. Taken together, these results indicate marked systemic organ toxicity in rats after subacute exposure to thiodicarb.

Avaliação da função diastólica no ventrículo esquerdo em mulheres hipertensas com excesso de peso ou obesidade

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular - Ramo de especialização: Ultrassonografia Cardiovascular

A behavioral intervention in a cohort of Japanese-Brazilians at high cardiometabolic risk

OBJECTIVE: To assess the effect of a health promotion program on cardiometabolic risk profile in Japanese-Brazilians. METHODS: A total of 466 subjects from a study on diabetes prevalence conducted in the city of Bauru, southeastern Brazil, in 2000 completed a 1-year intervention program (2005-2006) based on healthy diet counseling and physical activity. Changes in blood pressure and metabolic parameters in the 2005-2006 period were compared with annual changes in these same variables in the 2000-2005 period. RESULTS: During the intervention, there were greater annual reductions in mean (SD) waist circumference [-0.5(3.8) vs. 1.2(1.2) cm per year, p<0.001], systolic blood pressure [-4.6(17.9) vs. 1.8(4.3) mmHg per year, p<0.001], 2-hour plasma glucose [-1.2(2.1) vs. -0.2(0.6) mmol/L per year, p<0.001], LDL-cholesterol [-0.3(0.9) vs. -0.1(0.2) mmol/L per year, p<0.001] and Framingham coronary heart disease risk score [-0.25(3.03) vs. 0.11(0.66) per year, p=0.02] but not in triglycerides [0.2(1.6) vs. 0.1(0.42) mmol/L per year, p<0.001], and fasting insulin level [1.2(5.8) vs. -0.7(2.2) IU/mL per year, p<0.001] compared with the pre-intervention period. Significant reductions in the prevalence of impaired fasting glucose/impaired glucose tolerance and diabetes were seen during the intervention (from 58.4% to 35.4%, p<0.001; and from 30.1% to 21.7%, p= 0.004, respectively). CONCLUSIONS: A one-year community-based health promotion program brings cardiometabolic benefits in a high-risk population of Japanese-Brazilians.

Characterization of the effects of antiepileptic drugs on bone metabolism: in vitro studies with human osteoblastic and osteoclastic cells

Bone is constantly being molded and shaped by the action of osteoclasts and osteoblasts. A proper equilibrium between both cell types metabolic activities is required to ensure an adequate skeletal tissue structure, and it involves resorption of old bone and formation of new bone tissue. It is reported that treatment with antiepileptic drugs (AEDs) can elicit alterations in skeletal structure, in particular in bone mineral density. Nevertheless, the knowledge regarding the effects of AEDs on bone cells are still scarce. In this context, the aim of this study was to investigate the effects of five different AEDs on human osteoclastic, osteoblastic and co-cultured cells. Osteoclastic cell cultures were established from precursor cells isolated from human peripheral blood and were characterized for tartrate-resistant acid phosphatase (TRAP) activity, number of TRAP+ multinucleated cells, presence of cells with actin rings and expressing vitronectin and calcitonin receptors and apoptosis rate. Also, the involvement of several signaling pathways on the cellular response was addressed. Osteoblastic cell cultures were obtained from femur heads of patients (25-45 years old) undergoing orthopaedic surgery procedures and were then studied for cellular proliferation/viability, ALP activity, histochemical staining of ALP and apoptosis rate. Also the expression of osteoblast-related genes and the involvement of some osteoblastogenesis-related signalling pathways on cellular response were addressed. For co-cultured cells, osteoblastic cells were firstly seeded and cultured. After that, PBMC were added to the osteoblastic cells and co-cultures were evaluated using the same osteoclast and osteoblast parameters mentioned above for the corresponding isolated cell. Cell-cultures were maintained in the absence (control) or in the presence of different AEDs (carbamazepine, gabapentin, lamotrigine, topiramate and valproic acid). All the tested drugs were able to affect osteoclastic and osteoblastic cells development, although with different profiles on their osteoclastogenic and osteoblastogenic modulation properties. Globally, the tendency was to inhibit the process. Furthermore, the signaling pathways involved in the process also seemed to be differently affected by the AEDs, suggesting that the different drugs may affect osteoclastogenesis and/or osteoblastogenesis through different mechanisms. In conclusion, the present study showed that the different AEDs had the ability to directly and indirectly modulate bone cells differentiation, shedding new light towards a better understanding of how these drugs can affect bone tissue.

Properties of tantalum oxynitride thin films produced by magnetron sputtering: the influence of processing parameters

The main purpose of this work is to present and to interpret the change of structure and physical properties of tantalum oxynitride (TaNxOy) thin films, produced by dc reactive magnetron sputtering, by varying the processing parameters. A set of TaNxOy films was prepared by varying the reactive gases flow rate, using a N2/O2 gas mixture with a concentration ratio of 17:3. The different films, obtained by this process, exhibited significant differences. The obtained composition and the interpretation of X-ray diffraction results, shows that, depending on the partial pressure of the reactive gases, the films are: essentially dark grey metallic, when the atomic ratio (N + O)/Ta < 0.1, evidencing a tetragonal β-Ta structure; grey-brownish, when 0.1 < (N + O)/Ta < 1, exhibiting a face-centred cubic (fcc) TaN-like structure; and transparent oxide-type, when (N + O)/Ta > 1, evidencing the existence of Ta2O5, but with an amorphous structure. These transparent films exhibit refractive indexes, in the visible region, always higher than 2.0. The wear resistance of the films is relatively good. The best behaviour was obtained for the films with (N + O)/Ta ≈ 0.5 and (N + O)/Ta ≈ 1.3.

Size at birth and blood pressure in young adults: findings from a Brazilian birth cohort study

^len^lpt^aOBJETIVO: Descrever a prevalência de pressão arterial limítrofe (PAL) e hipertensão (HT) entre adultos jovens e avaliar a associação entre tamanho ao nascer e PAL/HT. MÉTODOS: Dados foram coletados do primeiro estudo brasileiro de coorte de nascimentos em Ribeirão Preto (sudeste do Brasil), iniciado em 1978/79. De 6.827 recém-nascidos de parto único hospitalar, 2.060 foram avaliados aos 23/25 anos. Foram realizadas coleta de sangue, avaliação antropométrica e obtidas informações sobre ocupação, escolaridade, hábitos de vida e doenças crônicas. Pressão arterial (PA) foi classificada em: 1) PAL: PA sistólica (PAS) ≥ 130 e < 140 mm Hg e/ou PA diastólica (PAD) ≥ 85 e < 90 mmHg; 2) HT: PAS ≥ 140 e/ou PAD ≥ 90 mm Hg. Foi aplicado modelo de regressão logística politômica. RESULTADOS: A prevalência de PAL foi de 13,5% (homens 23,2%) e a de HT, 9,5% (homens 17,7%). PAL foi independentemente associada com sexo masculino (RR 8,84; IC95%: 6,09;12,82), comprimento ao nascer ≥ 50 cm (RR 1,97; 1,04; 3,73), índice de massa corporal (IMC) ≥ 30 kg/m² (RR 3,23; 2,02; 5,15) e circunferência de cintura alterada (RR 1,61; 1,13;2,29), enquanto HT associou-se com sexo masculino (RR 15,18; 8,92;25,81), IMC ≥ 30 kg/m² (RR 3,68; 2,23;6,06), circunferência de cintura alterada (RR 2,68; 1,77;4,05) e glicemia elevada (RR 2,55; 1,27;5,10), mas não com comprimento ao nascer. CONCLUSÕES: As prevalências de PAL e HT entre os adultos jovens dessa coorte foram maiores em homens que em mulheres. Maior comprimento ao nascer foi associado com PAL, mas não com HT, enquanto peso ao nascer não foi associado com PAL ou HT. Fatores de risco do adulto explicaram a maioria dos aumentos de PAL ou HT.^les^aOBJETIVO: Describir la prevalencia de presión arterial limítrofe (PAL) e hipertensión (HT) entre adultos jóvenes y evaluar la asociación entre tamaño al nacer y PAL/HT. MÉTODOS: : Los datos fueron colectados en el primer estudio de cohorte de nacimientos brasileño en Ribeirao Preto (sureste de Brasil), iniciado en 1978/79. De 6.827 recién nacidos de parto único hospitalario, 2.060 fueron evaluados a los 23/25 años. Se realizaron colecta de sangre, evaluación antropométrica y obtenidas informaciones sobre ocupación, escolaridad, hábitos de vida y enfermedades crónicas. Presión arterial (PA) fue clasificada en: 1) PAL: PA sistólica (PAS) ≥ 130 y < 140 mm Hg y/o PA diastólica (PAD) ≥ 85 y < 90 mm Hg; 2) HT: PAS ≥ 140 y/o PAD ≥ 90 mm Hg. Se aplicó modelo de regresión logística politómica. RESULTADOS: La prevalencia de PAL fue de 13,5% (hombres 23,2%) y la de HT, 9,5% (hombres 17,7%). PAL fue independientemente asociada con sexo masculino (Riesgo Relativo - RR) 8,84; 95%IC: 6,09;12,82), estatura al nacer ≥ 50 cm (RR 1,97; 1,04; 3,73), índice de masa corporal (IMC) ≥ 30 kg/m2 (RR 3,23; 2,02; 5,15) y circunferencia de cintura alterada (RR 1,61; 1,13;2,29), mientras el HT se asoció con sexo masculino (RR 15,18; 8,92;25,81), IMC ≥ 30 kg/m2 (RR 3,68; 2,23;6,06), circunferencia de cintura alterada (RR 2,68; 1,77;4,05) y glicemia elevada (RR 2,55; 1,27;5,10), pero no con estatura al nacer. CONCLUSIONES: Las prevalencias de PAL y HT entre los adultos jóvenes de la cohorte fueron mayores en hombres que en mujeres. Mayor estatura al nacer fue asociado con PAL, pero no con HT, mientras que el peso al nacer no estuvo asociado con PAL o HT. Factores de riesgo de adulto explicaron la mayoría de los aumentos de PAL o HT.

Tissue composition and density impact on the clinical parameters for 125I prostate implants dosimetry

The MCNPX code was used to calculate the TG-43U1 recommended parameters in water and prostate tissue in order to quantify the dosimetric impact in 30 patients treated with (125)I prostate implants when replacing the TG-43U1 formalism parameters calculated in water by a prostate-like medium in the planning system (PS) and to evaluate the uncertainties associated with Monte Carlo (MC) calculations. The prostate density was obtained from the CT of 100 patients with prostate cancer. The deviations between our results for water and the TG-43U1 consensus dataset values were -2.6% for prostate V100, -13.0% for V150, and -5.8% for D90; -2.0% for rectum V100, and -5.1% for D0.1; -5.0% for urethra D10, and -5.1% for D30. The same differences between our water and prostate results were all under 0.3%. Uncertainties estimations were up to 2.9% for the gL(r) function, 13.4% for the F(r,θ) function and 7.0% for Λ, mainly due to seed geometry uncertainties. Uncertainties in extracting the TG-43U1 parameters in the MC simulations as well as in the literature comparison are of the same order of magnitude as the differences between dose distributions computed for water and prostate-like medium. The selection of the parameters for the PS should be done carefully, as it may considerably affect the dose distributions. The seeds internal geometry uncertainties are a major limiting factor in the MC parameters deduction.

PV system modeling by five parameters and in situ test

This paper focuses on a novel formalization for assessing the five parameter modeling of a photovoltaic cell. An optimization procedure is used as a feasibility problem to find the parameters tuned at the open circuit, maximum power, and short circuit points in order to assess the data needed for plotting the I-V curve. A comparison with experimental results is presented for two monocrystalline PV modules.