962 resultados para Heterogeneity


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Objective: Immunosenescence and cognitive decline are common markers of the aging process. Taking into consideration the heterogeneity observed in aging processes and the recently described link between lymphocytes and cognition, we herein explored the possibility of an association between alterations in lymphocytic populations and cognitive performance. Methods: In a cohort of cognitively healthy adults (n = 114), previously characterized by diverse neurocognitive/psychological performance patterns, detailed peripheral blood immunophenotyping of both the innate and adaptive immune systems was performed by flow cytometry. Results: Better cognitive performance was associated with lower numbers of effector memory CD4(+) T cells and higher numbers of naive CD8(+) T cells and B cells. Furthermore, effector memory CD4(+) T cells were found to be predictors of general and executive function and memory, even when factors known to influence cognitive performance in older individuals (e.g., age, sex, education, and mood) were taken into account. Conclusions: This is the first study in humans associating specific phenotypes of the immune system with distinct cognitive performance in healthy aging.

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Urothelial bladder carcinoma (UBC), the most frequent type (90%) of bladder cancer and the second most common malignancy of the urogenital region, is a relatively well understood type of cancer, with numerous studies concerning pathogenetic pathways, natural history and bladder tumor biology being reported. Despite this, it continues to remain a challenge in the oncology field, mostly due to its relapsing and progressive nature, and to the heterogeneity in the response to cisplatin-containing regimens. Although the formulae based on clinical staging and histopathological parameters are classically used as diagnostic and prognostic tools, they have proven insufficient to characterize the individual biological features and clinical behaviour of the tumours. Understanding the pathobiology of the disease can add important information to these classical criteria, and contribute to accurately predict outcome and individualize therapy for UBC patients. In this line of investigation, we found that tumour angiogenesis and lymphangiogenesis, the process of invasion and metastasis and the energy metabolism reprogramming/tumour microenvironment encompass several potential biomarkers that seem to infl bladder cancer aggressiveness and chemoresistance. We particularly highlight the roles of lymphovascular invasion, and of RKIP, CD147 and MCT1 immunoexpressions, as relevant prognostic and/or predictive biomarkers, and as promising areas of therapeutic intervention, eliciting for the development of additional studies that can validate and further explore these biomarkers.

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The Amazon River basin is important in the contribution of dissolved material to oceans (4% worldwide). The aim of this work was to study the spatial and the temporal variability of dissolved inorganic materials in the main rivers of the Amazon basin. Data from 2003 to 2011 from six gauging stations of the ORE-HYBAM localized in Solimões, Purus, Madeira and Amazon rivers were used for this study. The concentrations of Ca2+, Na+, K+, Mg2+, Cl-, SO4 -2, HCO3 - and SiO2 were analyzed. At the stations of Solimões and Amazon rivers, the concentrations of Ca2+, Mg2+, HCO3 - and SO4 -2 had heterogeneous distribution over the years and did not show seasonality. At the stations of Madeira river, the concentration of these ions had seasonality inversely proportional to water discharge (dilution-concentration effect). Similar behavior was observed for the concentrations of Cl- and Na+ at the stations of the Solimões, Amazon and Madeira rivers, indicating almost constant release of Cl- and Na+ fluxes during the hydrological cycle. K+ and SiO2 showed almost constant concentrations throughout the years and all the stations, indicating that their flows depend on the river discharge variation. Therefore, the temporal variability of the dissolved inorganic material fluxes in the Solimões and Amazon rivers depends on the hydro-climatic factor and on the heterogeneity of the sources. In the Madeira and Purus rivers there is less influence of these factors, indicating that dissolved load fluxes are mainly associated to silicates weathering. As the Solimões basin contributes approximately 84% of the total flux of dissolved materials in the basin and is mainly under the influence of a hydro-climatic factor, we conclude that the temporal variability of this factor controls the temporal variability of the dissolved material fluxes of the Amazon basin.

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We test the predictive ability of the transitory deviations of consumption from its common trend with aggregate wealth and labour income, cay, for both future equity and housing risk premia in emerging market economies. Using quarterly data for 31 markets, our country-level evidence shows that forecasting power of cay vis-à-vis stock returns is high for Brazil, China, Colombia, Israel, Korea, Latvia and Malaysia. As for housing returns, the empirical evidence suggests that financial and housing assets are perceived as complements in the case of Chile, Russia, South Africa and Thailand, and as substitutes in Argentina, Brazil, Hong Kong, Indonesia, Korea, Malaysia, Mexico and Taiwan. Using a panel econometric framework, we find that the cross-country heterogeneity observed in asset return predictability does not accrue to regional location, but can be attributed to differences in the degree of equity market development and in the level of income.

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Dissertação de mestrado em Ordenamento e Valorização de Recursos Geológicos

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Cancer is a major cause of morbidity and mortality worldwide, with a disease burden estimated to increase in the coming decades. Disease heterogeneity and limited information on cancer biology and disease mechanisms are aspects that 2D cell cultures fail to address. We review the current "state-of-the-art" in 3D Tissue Engineering (TE) models developed for and used in cancer research. Scaffold-based TE models and microfluidics, are assessed for their potential to fill the gap between 2D models and clinical application. Recent advances in combining the principles of 3D TE models and microfluidics are discussed, with a special focus on biomaterials and the most promising chip-based 3D models.

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Tese de Doutoramento em Ciências da Saúde.

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INTRODUCTION: The geriatric depression (GD) represents one of the most frequent psychiatric disorders in outpatient services specialized in old-age treatment. OBJECTIVE: The course of two illustrative cases of GD is discussed, highlighting its clinical picture after antidepressant treatment and underlining variables related to disease prognosis, treatment effectiveness and conversion to major cognitive disorders such as vascular dementia (VD). METHODS: The cognitive performance, depressive symptoms, autonomy and brain structural measurements as white matter hyperintensities (WMH) and hippocampal size, and microstructural integrity of WM with diffusion tensor imaging were followed during four years. RESULTS: Case 1, with a severe degree of WMH, was associated with worsening cognition and increasing functional disability. Case 2, with mild WMH, an improvement of cognitive functioning could be seen. CONCLUSIONS: The existence of different subtypes of GD, as presented in this report, points a pathophysiological heterogeneity of GD, and suggests a possible continuum vascular depression (VaDp) and vascular cognitive impairment (VCI).

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Metabolic adaptation is considered an emerging hallmark of cancer, whereby cancer cells exhibit high rates of glucose consumption with consequent lactate production. To ensure rapid efflux of lactate, most cancer cells express high levels of monocarboxylate transporters (MCTs), which therefore may constitute suitable therapeutic targets. The impact of MCT inhibition, along with the clinical impact of altered cellular metabolism during prostate cancer (PCa) initiation and progression, has not been described. Using a large cohort of human prostate tissues of different grades, in silico data, in vitro and ex vivo studies, we demonstrate the metabolic heterogeneity of PCa and its clinical relevance. We show an increased glycolytic phenotype in advanced stages of PCa and its correlation with poor prognosis. Finally, we present evidence supporting MCTs as suitable targets in PCa, affecting not only cancer cell proliferation and survival but also the expression of a number of hypoxia-inducible factor target genes associated with poor prognosis. Herein, we suggest that patients with highly glycolytic tumours have poorer outcome, supporting the notion of targeting glycolytic tumour cells in prostate cancer through the use of MCT inhibitors.

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Dissertação de mestrado integrado em Engenharia Civil

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Dissertação de mestrado integrado em Engenharia Civil

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Inter-individual heterogeneity is evident in aging; education level is known to contribute for this heterogeneity. Using a cross-sectional study design and network inference applied to resting-state fMRI data, we show that aging was associated with decreased functional connectivity in a large cortical network. On the other hand, education level, as measured by years of formal education, produced an opposite effect on the long-term. These results demonstrate the increased brain efficiency in individuals with higher education level that may mitigate the impact of age on brain functional connectivity.

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Dissertação de Mestrado (Programa Doutoral em Informática)

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Relatório de estágio de mestrado em Ensino de Inglês e Espanhol no 3º Ciclo do Ensino Básico e no Ensino Secundário

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OBJECTIVE: To characterize left ventricular regional myocardial function through tissue Doppler echocardiography in healthy adults and to assess the influence of aging in this function. METHODS: In 45 healthy volunteers divided in two groups (< 45 and > 45 years old) we assessed longitudinal and radial regional function (velocities, times intervals and velocity-time integrals). Data were compared in each group and between groups. RESULTS: Systolic function: a) longitudinal: higher velocities and integrals in lateral and inferior walls and in basal segments, with a trend to reduction of these parameters with aging; b) radial: higher basal velocities, no significant change with aging. Diastolic function: a) longitudinal: higher velocities in lateral and inferior walls and in basal segments. With aging e and e/a velocities and integrals decreased, a increased and older individuals showed lower percentage of segments with e/a >1; b) radial: aging was associated with lower e and higher a velocities. CONCLUSION: 1) Tissue Doppler echocardiography detects physiological differences between regional myocardial function of different ventricular segments, in velocities, times intervals and integrals, with physiological heterogeneity and asynchrony; 2) Many of these data are age dependent; 3) Our data contribute to define normal values, and may become useful when compared with data from populations with heart diseases.