1,721,086 research outputs found

    Interactions between oxidative stress and cardiorespiratory fitness. Old and new biomarkers

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    Enzymes, nonenzymatic total antioxidant capacity and reactive oxygen species-induced modifications on lipids, DNA and proteins are usually used to evaluate oxidative stress (OS) in humans. Asymmetric dimethylarginine (ADMA) has been suggested as a new OS marker. Antioxidant status may be improved by exogenous antioxidant intake or endurance training, which increases cardiorespiratory fitness (CRF). We reviewed studies on both OS markers and CRF. All markers were affected by age, gender, health, and exercise type. Exercise training with or without antioxidant interventions improved CRF and/or OS old markers, whereas more studies are needed for ADMA. CRF has high clinical significance and its measure should be included in the health assessment and in the redox status evaluated through OS markers

    Effect of cocoa products and flavanols on platelet aggregation in humans: a systematic review

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    Previous evidence suggested an active role of cocoa products and flavanols in modulating platelet aggre- 1 gation. However, cocoa flavanols are characterized by a low bioavailability that can deeply affect their presence in biological fluids and raise questions on their biological effect in humans. We performed a sys- tematic search on Medline, Embase, Cochrane and ProQuest databases, until April 2015, on the effect of cocoa products on platelet aggregation in human intervention studies. We identified 13 interventions, of which only five involved repeated administration. Different effects were observed on the basis of the platelet aggregation test used, whereas neither a longer duration of treatment nor a higher dose was associated with a higher inhibition of platelet aggregation. In conclusion, the reviewed results suggest that consumption of cocoa products in bolus administration positively affects platelet aggregation in both healthy subjects and diseased patients. On the other hand, more evidence is required in order to assess the effect of long-term cocoa product ingestion and to identify the bioactive components involved

    Effect of flavonoids on circulating levels of TNF-(alfa ) and IL-6 in humans: A systematic review and meta-analysis

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    Epidemiological or in vitro evidence suggests a potential role for flavonoids as anti-inflammatory agents; we investigated the effect of flavonoids-rich foods or supplements on tumor necrosis factor- alpha (TNF-alfa) and interleukin-6 (IL-6) in long-term placebo-controlled human interven- tion trials. From 110 human intervention studies selected (MEDLINE, EMBASE, CHORANE, and FSTA databases), 32 long-term placebo-controlled trials were suitable for meta-analysis. After sensitivity analysis, seven studies imputed of bias were excluded and 25 studies were analyzed (TNF-a, n = 2404; IL-6, n = 2174). Levels of TNF-a decreased after flavonoid con- sumption in the fixed model only (mean difference (MD) (95% CI): −0.098 (−0.188, –0.009), p = 0.032), but metaregression results showed that neither higher dose, nor a longer duration of intervention were associated with a greater effect size. Subgroup analysis did not reveal any significant effect for quercetin and soy, but other sources (red wine, pomegranate, and tea extracts) showed a significant effect size both in fixed (MD (95% CI): TNF-alfa−0.449 (−0.619, –0.280), p < 0.001; IL-6 −0.346 (−0.612, –0.079), p = 0.011) and random (MD (95% CI): TNF-alfa−0.783 (−1.476, –0.090), p = 0.027; IL-6, −0.556 (−1.062, –0.050), p = 0.031) effect models. High-quality placebo-controlled trials are needed in order to identify flavonoids as the active ingredients

    Risks of misinterpretation in the evaluation of the effect of fruit-based drinks in postprandial studies

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    It has been suggested that some fruit-based drinks (FBD) may delay the onset of postprandial stress, which is involved in the pathogenesis of many diseases. The majority of the studies, which have investigated the effects of FBD on postprandial stress, involved a placebo that was a drink with the same content in sugars or carbohydrates of the FBD, but without the bioactive antioxidant compounds. These studies were aimed more at evaluating the effect of the antioxidants rather than the effect of the FBD as a whole. Only 4 studies compared the effect of FBD with water as control and did not support the hypothesis that FBD could inhibit postprandial dysmetabolism, as well as the studies that compared the effect of orange juice and cola. Overall, the results suggest a complex relationship between postprandial dysmetabolism, inflammation, and oxidative stress. Furthermore, the inflammatory and oxidative stress markers need further analytical validation and normal ranges should be established in order to reach a firm conclusion. Finally, caution should be taken in the interpretation of the effect of FBD in postprandial studies and the reviewed results suggest that dietary recommendations should aim to limit rather than increase sugar-sweetened beverages consumption

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Experimental colitis: decreased Octn2 and Atb0+ expression in rat colonocytes induces carnitine depletion that is reversible by catnitine-loaded liposomes.

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    Carnitine transporters have recently been implicated in susceptibility to inflammatory bowel disease (IBD). Because carnitine is required for beta-oxidation, it was suggested that decreased carnitine transporters, and hence reduced carnitine uptake, could lead to impaired fatty acid oxidation in intestinal epithelial cells, and to cell injury. We investigated this issue by examining the expression of the carnitine transporters OCTN2 and ATB0+, and butyrate metabolism in colonocytes in a rat model of IBD induced by trinitrobenzene sulfonic acid (TNBS). We found that Octn2 and Atb0+ expression was decreased in inflammatory samples at translational and functional level. Butyrate oxidation, evaluated based on CO2 production and acetyl-coenzyme A synthesis, was deranged in colonocytes from TNBS-treated rats. Treatment with carnitine-loaded liposomes corrected the butyrate metabolic alterations in vitro and reduced the severity of colitis in vivo. These results suggest that carnitine depletion in colonocytes is associated with the inability of mitochondria to maintain normal butyrate beta-oxidation. Our data indicate that carnitine is a rate-limiting factor for the maintenance of physiological butyrate oxidation in colonic cells. This hypothesis could also explain the contradictory therapeutic efficacy of butyrate supplementation observed in clinical trials of IBD.-D'Argenio, G., Calvani, M., Casamassimi, A., Petillo, O., Margarucci, S., Rienzo, M., Peluso, I., Calvani, R., Ciccodicola, A., Caporaso, N., and Peluso, G. Experimental colitis: decreased Octn2 and Atb0+ expression in rat colonocytes induces carnitine depletion that is reversible by carnitine-loaded liposomes

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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