1,720,966 research outputs found
Colonic Metabolism of Polyphenols From Coffee, Green Tea, and Hazelnut Skins
Full text linkDietary polyphenolic compounds are poorly absorbed in
the small intestine. The absorbed fraction follows the common metabolic pathway of drugs, undergoing phase II enzymatic detoxification with the conjugation of glucuronic acid, sulfate, and methyl groups. However, the unabsorbed fraction can reach the colon, becoming available for the wide array of enzymes produced by the local commensal microbiota. Gut bacteria can hydrolyze glycosides, glucuronides, sulfates, amides, esters, and lactones and are able to break down the polyphenolic skeleton and perform
reactions of reduction, decarboxylation, demethylation, and
dehydroxylation. These complex modifications generate several low–molecular-weight metabolites that can be efficiently absorbed in situ, subsequently undergoing further phase II metabolism, locally and/or at the liver level, before entering the systemic blood circulation and finally being excreted in urine in substantial quantities that exceed the excretion of phenolic metabolites formed in the upper gastrointestinal tract. This brief work focuses on the phenolic composition and colonic microbial transformation of 2 of the most polyphenol-rich dietary sources, namely, green tea and
coffee, and a new interesting and innovative ingredient, hazelnut skin, recently evaluated as one of the richest edible sources of polyphenolic compounds
Macrophage polarization: the answer to the diet/inflammation conundrum?
No full textMacrophages, a heterogeneous and ubiquitous cell population representing up to 15% of the cellular content of different types of tissue, are the principal cell mediators in response to pathogens, inflammation process, tissue homeostasis and repair and play a pivotal role in atherosclerosis and insulin resistance because of their capacity to be the major source of inflammatory cytokines, which can function through paracrine and endocrine mechanisms. Recently, differently activated macrophage populations have been described, depending on a large variety of microenvironmental signals, and it is now recognized that their activation plays a crucial role in the development and progression of atherosclerosis. There is good evidence of the ability of conjugated linoleic acids and polyphenolic compounds to modulate inflammation in experimental models involving macrophages. This observation leaves room to the intriguing hypothesis that macrophage polarization could represent one of the unifying mechanisms through which specific food components can exert anti-inflammatory effects in humans, contributing to the prevention of chronic diseases strongly linked to inflammation, such as atherosclerosis. Future studies should be addressed to substantiate this hypothesis, investigating whether or not physiological concentrations of food-derived metabolites can per- turb macrophage activation in vitro. On the in vivo side, the evaluation of macrophage popu- lations in tissues, however complex, should be included among the analyses performed in observational and intervention studies, in order to understand if macrophage activation is involved in the anti-inflammatory activity of a specific dietary regimen
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
New Insight and Knowledge on anti-inflammatory Effectiveness of dietary phenolics: a work-in-progress report of the NIKE Project
No full textDiet may be an important factor in managing inflammatory bowel disease (IBD) symptoms. Patients with IBD who reached clinical remission have an expected relapse rate of ≈50%. We aim to explore the pomegranate juice supplementation as a potential strategy for the prevention of clinical relapse in asymptomatic IBD patients at high risk of flare.
Methods: Faecal calprotectin is used as a surrogate marker of mucosal inflammation to predict the risk of relapse [1]. In a double-blind, randomised controlled trial (RCT), patients with IBD, ulcerative colitis and Crohn's disease, in stable clinical remission (≥3 months) have to consume either 125 mL pomegranate juice or placebo twice daily for 12 weeks. Before and after each intervention, biological samples (blood, urine, stool, and bowel biopsies) are collected. A food frequency questionnaire [2] and a dietary diary are administered. This trial is registered at ClinicalTrials.gov as NCT03000101 and conducted at the St. Orsola-Malpighi Hospital in Bologna (Italy).
Results: Clinical, biochemical, and endoscopic parameters are assessed. The primary outcome is to measure changes to the faecal calprotectin. The secondary outcomes include systemic and mucosal changes of biochemical and molecular inflammatory response markers [3]. The compliance of trial participants is tested by a uHPLC system coupled to a mass spectrometer to quantify ellagitannin (ET)-derived metabolites in plasma and urine. Plasma level of trimethylamine-N-oxide is also evaluated as a potential biomarker of disease activity in IBD [4]. The recruitment is currently ongoing; no adverse events are observed. Furthermore, we are studying the effect of different combinations of ET-derived metabolites on modulation of expression of selected inflammatory response genes in polarised primary human macrophages [5].
Conclusions: The screening procedure is appeared to be feasible; the main reason why individuals are not included in the study is the treatment with corticosteroids within the last 2 months. Because the RCT is still ongoing, no final results can be presented. The in vitro preliminary findings suggest that supplementation with ET-derived metabolites may modulate the inflammation processes in polarised human macrophages. Further experiments and analysis are underway.
Acknowledgments. This study is funded by the Italian Ministry of Education, University and Research MIUR - SIR Programme (grant no. RBSI14LHMB, funded to F. Danesi). Pomegranate juice is supplied by Gat Foods (M.P. Hefer; Israel). All experimental beverages are provided by Conserve Italia (Bologna; Italy).
References. [1] Konikoff & Denson. Inflamm Bowel Dis 2006; 12:524-34. [2] Pellegrini et al. J Nutr 2007; 137:93-8. [3] Mesko et al. BMC Med Genomics 2010; 3:15. [4] Wilson et al. Dig Dis Sci 2015; 60:3620-30. [5] Dall’Asta et al. Nutr Metab Cardiovasc Dis 2012; 22:387-92
Effects of naringenin and its phase II metabolites on in vitro human macrophage gene expression.
No full textNaringenin, together with its glycosidic forms, is a flavanone abundant in grapefruit and orange. It has been detected in human plasma, following citrus juice intake, at sub-μmolar concentrations, and its main phase II conjugated metabolites (naringenin-7-O-glucuronide and narigenin-4’-O-glucuronide) have been identified in urine. Recent evidence suggests a potential active anti-inflammatory role of flavonoids on macrophages, cells actively involved in atherogenesis. The aim of this study was to evaluate the effects of naringenin and its phase II metabolites on the expression of specific genes in differently activated macrophages at concentrations coherent with dietary exposure. Results suggest that phase II metabolites, as well as the aglyconic form of naringenin, were able to perturb macrophage gene expression in directions that are not always consistent with anti-inflammatory effects. Moreover, the effects of metabolites were not always consistent with each other and with those of their aglycone, underlining the paramount importance of testing physiological forms of phytochemicals within in vitro experimental models. In vivo studies are needed to further explore these observations and investigate their practical consequences
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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