114 research outputs found

    Central/peripheral fat mass ratio is associated with increased risk of hypertension in hiv-infected patients

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    The data on the risk of hypertension in human immunodeficiency virus (HIV)-infected patients, particularly in those with lipodystrophy, are controversial. The authors assessed the impact of lipodystrophy on hypertension in a cohort of HIV-infected adults receiving combination antiretroviral therapy. This was a cross-sectional study in which lipodystrophy (clinically and fat mass ratio [FMR]-defined), blood pressure, and body composition (dual-energy x-ray absorptiometry and computed tomography) were evaluated in 368 HIV adults. The prevalence of hypertension in HIV patients with or without clinically or FMR-defined lipodystrophy was similar (with clinical lipodystrophy 35.3% vs without 32.9%, not significant; with FMR lipodystrophy 41.7% vs without 32.2%, not significant). When HIV-infected patients were classified into 4 categories of fat distribution (based on the presence or absence of lipoatrophy and abdominal prominence), isolated lipoatrophy was not significantly associated with hypertension, but patients with isolated central fat accumulation and mixed forms of lipodystrophy had a significantly higher prevalence of hypertension. Hypertensive HIV patients had significantly higher total fat, central, and central/peripheral fat mass ratio than normotensive ones. After adjustment for age, sex, smoking, and body mass index, hypertension remains significantly associated with central/peripheral fat mass ratio (odds ratio, 1.258; 95% confidence interval, 1.008-1.569). Hypertension was not more prevalent in lipodystrophic HIV-infected patients, but was significantly associated with central/peripheral fat mass ratio. © 2012 Wiley Periodicals, Inc

    Lipodystrophy defined by Fat Mass Ratio in HIV-infected patients is associated with a high prevalence of glucose disturbances and insulin resistance

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    Introduction: Combined antiretroviral therapy (cART) in the treatment of HIV-1 infection has been associated with complications, including lipodystrophy, hyperlipidaemia, insulin resistance (IR) and diabetes.Aims: To compare the prevalence of glucose homeostasis disturbances and IR in HIV patients on cART according to the presence of lipodystrophy (defined clinically and by Fat Mass Ratio) and different patterns of fat distribution and to establish their associations.Design: Cross-sectional cohort study.Methods: We evaluated body composition and IR and insulin sensitivity indexes in 345 HIV-infected adults.Results: Patients with clinical lipodystrophy (CL) had higher plasma glucose levels than patients without CL, without significant differences in plasma insulin levels, A1c, HOMA-IR, HOMA-B, QUICKI, or MATSUDA index. Patients with lipodystrophy defined by FMR had higher plasma glucose and insulin levels, A1c, HOMA-IR, QUICKI and MATSUDA than patients without lipodystrophy, without differences in HOMA-B. Higher insulin resistance (HOMA-IR ≥ 4) was present in patients with FMR-defined lipodystrophy. Patients with FMR-defined lipodystrophy had a higher prevalence of IFG, IGT and DM than patients without lipodystrophy. Significant associations between HOMA-IR and total, central and central/peripheral fat evaluated by CT at abdominal level were found and no association between HOMA-IR and peripheral fat. Association between HOMA-IR and total and trunk fat but no association with leg and arm fat (evaluated by DXA) was found.Conclusions: IR and glucose disturbances were significantly increased in patients with FMR-defined lipodystrophy. FMR lipodystrophy definition seems to be a more sensitive determinant of insulin resistance and glucose disturbances than clinical definition. © 2012 Freitas et al.; licensee BioMed Central Ltd.Research Fellowship Dr. Manuel Almeida Ruas, Portuguese Society of Diabetology. Research Fellowship of the Portuguese Association for Clinical Study of AIDS. Research Grant to support doctoral studies in the area of HIV/ AIDS, GlaxoSmithKline Foundation of Health Sciences

    Purification, structure and immunobiological activity of an arabinan-rich pectic polysaccharide from the cell walls of prunus dulcis seeds

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    The structure and bioactivity of a polysaccharide extracted and purified from a 4MKOH + H3BO3 solution from Prunus dulcis seed cell wall material was studied. Anion-exchange chromatography of the crude extract yielded two sugar-rich fractions: one neutral (A), the other acidic (E). These fractions contain a very similar monosaccharide composition: 5:2:1 for arabinose, uronic acids and xylose, respectively, rhamnose and galactose being present in smaller amounts. As estimated by size-exclusion chromatography, the acidic fraction had an apparent molecular mass of 762kDa. Methylation analysis (from the crude and fractions A and E), suggests that the polysaccharide is an arabinan-rich pectin. In all cases, the polysaccharides bear the same type of structural Ara moieties with highly branched arabinan-rich pectic polysaccharides. The average relative proportions of the arabinosyl linkages is 3:2:1:1 for T-Araf:(1!5)-Araf:(1!3,5)-Araf:(1!2,3,5)-Araf. The crude polysaccharide extract and fractions A and E induced a murine lymphocyte stimulatory effect, as evaluated by the in vitro and in vivo expression of lymphocyte activation markers and spleen mononuclear cells culture proliferation. The lymphocyte stimulatory effect was stronger on B- than on T-cells. No evidence of cytotoxic effects induced by the polysaccharide fractions was found.Fundação para a Ciência e Tecnologia (FCT) - PRAXIX XXI/BD/18401/98

    Foundations and trends of high resolution energy dispersive PIXE (HiRED-PIXE)

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    High Resolution Particle Induced X-ray Emission, for short HR-PIXE, dates back to 1977 and is, therefore, nearly as old as standard PIXE itself. Until roughly ten years ago, High Resolution PIXE (HR-PIXE) work used only wavelength dispersive spectrometers (WDS). The installation, in 2008, of an X-ray Microcalorimeter Spectrometer, XMS at CTN (ITN at the time) 3MV tandetron, altered this situation and, as can be recognised today, will lead to major changes in PIXE, and open up many possibilities that have been hindered so far. In this work, motives, developments, important breakthrough results obtained until now, and a case study displaying speciation data and complementary information from nuclear magnetic relaxometry, are presented and discussed, showing the full quantitative potential of High Resolution Energy Dispersion PIXE (HiRED-PIXE), in particularly the opening up of the possibility to establish fast and efficient methods for quantitative elemental speciation in unknown samples

    Sweet whey cheese matrices inoculated with the probiotic strain Lactobacillus paracasei LAFTI® L26

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    Consumption of dairy products containing viable probiotic strains has increased dramatically in recent years, owing to general health claims associated therewith. This trend has boosted diversification of the portfolio of said products, including whey cheese matrices. However, taking into account the relatively poor organoleptic and textural features of these matrices, improvement is in order via incorporation of selected additives, provided that viability of the strains is duly assayed. Lactobacillus paracasei LAFTI® L26 was accordingly incorporated into whey protein solid matrices, in the presence of several additives aimed at enhancing their organoleptic appeal and textural performance. These matrices were produced from a combination of either ovine or bovine whey (or a mixture thereof) with ovine milk, and were inoculated at 10% (v/v) with the probiotic strain. Sugar, sugar and aloe vera, sugar and chocolate, and sugar and jam were further added, and the resulting products were then stored at 7 ◦C for 21 d. In general, viable cell numbers remained high in all experimental matrices throughout storage. Despite the observed low extents of breakdown, proteolytic activities by the end of storage were higher in matrices containing jam. Furthermore, L. paracasei partially converted lactose into lactic acid in these matrices. Additives enhanced the organoleptic features of whey cheeses, and produced different textural patterns. The higher sensory scores were attained by matrices containing sugar: sugar and aloe vera received the best scores by 3 d of storage, but these scores decreased as storage time elapsed

    Fresh-cut melon quality during storage: an NMR study of water transverse relaxation time

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    Molecular mobility is a fundamental parameter which reflects the dynamic properties of food components and contributes to food degradation reactions comprehension. Fresh-cut fruits have become an important food market segment. However, processing of fruits promotes faster its physiological deterioration, biochemical changes and microbial degradation. The purpose of this work was to use NMR methodology as a tool to evaluate fresh-cut fruit quality, during storage at refrigerated conditions. The fresh-cut melon transverse relaxation time (T2) was measured for a period of 7 days of storage at 5 °C. The relationship between the obtained values, microstructure and quality parameters was investigated. In general, results show the existence of one class of water fluidity in the system, the one present in cells after processing. T2, a measure of this fluidity, is affected by the processing and storage time. Also, it is possible to find a close relationships between T2 and quality parameters of total colour difference (TCD), firmness and aw. As T2 increases TCD also increases, while firmness and aw decrease. These results highlight the usefulness of NMR methodology application in food science.Author Joana F. Fundo acknowledges Fundacao para a Ciencia e a Tecnologia (grant SFRH/BD/62176/2009). The authors acknowledge the Portuguese NMR Network and Strategic Project PEst-C/CTM/LA0025/2013-14. This work was supported by National Funds from FCT through project PEst-OE/EQB/LA0016/201

    Genetic variability and natural selection at the ligand domain of the Duffy binding protein in Brazilian Plasmodium vivax populations.

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    Background. Plasmodium vivax malaria is a major public health challenge in Latin America, Asia and Oceania, with 130-435 million clinical cases per year worldwide. Invasion of host blood cells by P. vivax mainly depends on a type I membrane protein called Duffy binding protein (PvDBP). The erythrocyte-binding motif of PvDBP is a 170 amino-acid stretch located in its cysteine-rich region II (PvDBPII), which is the most variable segment of the protein. Methods. To test whether diversifying natural selection has shaped the nucleotide diversity of PvDBPII in Brazilian populations, this region was sequenced in 122 isolates from six different geographic areas. A Bayesian method was applied to test for the action of natural selection under a population genetic model that incorporates recombination. The analysis was integrated with a structural model of PvDBPII, and T- and B-cell epitopes were localized on the 3-D structure. Results. The results suggest that: (i) recombination plays an important role in determining the haplotype structure of PvDBPII, and (ii) PvDBPII appears to contain neutrally evolving codons as well as codons evolving under natural selection. Diversifying selection preferentially acts on sites identified as epitopes, particularly on amino acid residues 417, 419, and 424, which show strong linkage disequilibrium. Conclusions. This study shows that some polymorphisms of PvDBPII are present near the erythrocyte-binding domain and might serve to elude antibodies that inhibit cell invasion. Therefore, these polymorphisms should be taken into account when designing vaccines aimed at eliciting antibodies to inhibit erythrocyte invasion

    Genotoxic agents promote the nuclear accumulation of annexin A2: role of annexin A2 in mitigating DNA damage

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    Annexin A2 is an abundant cellular protein that is mainly localized in the cytoplasm and plasma membrane, however a small population has been found in the nucleus, suggesting a nuclear function for the protein. Annexin A2 possesses a nuclear export sequence (NES) and inhibition of the NES is sufficient to cause nuclear accumulation. Here we show that annexin A2 accumulates in the nucleus in response to genotoxic agents including gamma-radiation, UV radiation, etoposide and chromium VI and that this event is mediated by the nuclear export sequence of annexin A2. Nuclear accumulation of annexin A2 is blocked by the antioxidant agent N-acetyl cysteine (NAC) and stimulated by hydrogen peroxide (H2O2), suggesting that this is a reactive oxygen species dependent event. In response to genotoxic agents, cells depleted of annexin A2 show enhanced phospho-histone H2AX and p53 levels, increased numbers of p53-binding protein 1 nuclear foci and increased levels of nuclear 8-oxo-2'-deoxyguanine, suggesting that annexin A2 plays a role in protecting DNA from damage. This is the first report showing the nuclear translocation of annexin A2 in response to genotoxic agents and its role in mitigating DNA damage.Natural Sciences and Engineering Research Council of Canada (NSERC); European Union [PCOFUND-GA-2009-246542]; Foundation for Science and Technology of Portugal; Beatrice Hunter Cancer Research Institute; Terry Fox Foundationinfo:eu-repo/semantics/publishedVersio
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