1,720,962 research outputs found
Involvement of Toll-like receptor 4 on small intestine neuromuscular dysfunction in a mouse model of high-fat diet-induced obesity
No full textBackground and Aim. High fat diet (HFD)-induced obesity determines gut dysbiosis, delayed gastrointestinal (GI) transit and Toll-like receptor 4 (TLR4)-dependent neuronal loss in mice (Anitha et al., 2016). In this study, we aimed to assess TLR4 role in tuning small bowel contractility to identify the neurotransmitter pathways affected by HFD-induced obesity. Methods. TLR4-/- and wild-type (WT) C57BL/6J male mice were fed with standard-diet (SD; 18% kcal fat) or HFD (60% kcal fat) for 8 weeks. GI transit was measured by in vivo distribution of nonabsorbable-FITC-labeled dextran, fecal pellet frequency and water content. In ileal longitudinal muscle-myenteric plexus, neuronal HuC/D and neuronal NOS (nNOS), and glial S100β distribution was analyzed by confocal microscopy. Changes in ileal muscle tension were isometrically recorded following: i) electric field stimulation (EFS, 0-40 Hz), ii) 10 Hz-EFS in non-adrenergic non-cholinergic (NANC) condition (1 μM guanethidine + 1 μM atropine) with or without 10 μM 1400W (iNOS inhibitor) or 100 μM L-NAME (pan-NOS inhibitor) as previously described by Caputi et al (2017). Data are presented as mean±SEM. Results. In TLR4-/- mice, SD determined a reduced excitatory neurotransmission (-23±3%; n=6 animals, p<0.05) together with an increased NANC relaxation (+36±2%; n=5 animals, p<0.05) mediated by both iNOS- and nNOS-derived NO, which was found abolished in HFD-fed animals. In WT mice, HFD impaired GI transit (-20±4%; n=6 animals, p<0.05), increased tachykininergicmediated responses in NANC conditions while decreasing cholinergic-mediated contraction (31±3%; n=5 animals, p<0.05). After SD, increased S100β immunofluorescence (+82±6%; n=5, animals, p<0.05) and reduced number of nNOS+ neurons (-24±3%; n=5 animals, p<0.05) were found in TLR4-/- mice. HFD determined reactive enteric gliosis in WT mice whereas reduced S100β immunoreactivity in TLR4-/- mice. These findings were associated to a decreased number of nNOS+ neurons in WT and to a further decrease in TLR4-/- mice (by -11±2% and -23±4%, respectively; n=5 animals, p<0.05). Conclusion. HFD-induced chronic systemic low-grade inflammation caused complex morphofunctional neuromuscular rearrangements, characterized by intestinal dysmotility and enteric reactive gliosis. The absence of TLR4 appears to partially protect from HFD detrimental effects, suggesting the involvement of TLR4 signaling in HFD-mediated GI molecular events
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Functional alteration of gastrointestinal tract in a mouse model of diet induced-obesit
No full textBackground and Aim: Obesity, beyond an excessive fat accumulation, induces the onset and progression of chronic disorders such as cardiovascular disease, type 2 diabetes and cancer (1). Obesity is also associated with gastrointestinal dysfunctions, including altered gastric emptying, intestinal dysmotility and constipation (2). The aim of the study is to evaluate the small intestine contractility and gut motility in a mouse model of diet-induced obesity (DIO). Methods: C57BL/6 female mice (4-5 weeks of age) were fed with standard diet (SD, 10% of energy from fat) or high fat diet (HFD, 60% of energy from fat) for 8 weeks. Body weight, fecal pellet frequency and stool water content were evaluated the day before sacrifice. Gastrointestinal transit was assessed 30 minutes after intragastric administration of nonabsorbable fluorescein isothiocyanate labeled dextran (FITC-dextran 70 KDa). Isolated ileum segments were isometrically mounted in organ baths containing Krebs solution and changes in muscle tension were recorded following addition of either carbachol (0.01-100 μM), KCl (60 mM) and after electric field stimulation (EFS, 1-40 Hz). The inhibitory contractile response was evaluated by performing the EFS at 10 Hz in non-adrenergic non-cholinergic (NANC) conditions (1 μM atropine, 1 μM guanethidine) in the absence or presence of 10 μM 1400W or 100 μM L-NAME. Results: HFD-mice (n=35) displayed an increase of body weight after 8 weeks on diet (21.28 ± 0.46 g) compared to control SD mice (n=19, 19.26 ± 0.33 g, p<0.05) and a 50% reduction in fecal pellet extruded in 1-hour period and in stool water content. Gastrointestinal transit showed a significantly reduction in HFD-mice. A slight downward shift of the concentration-response curve to CCh occurred in HFD-mice, and KCl-mediated contractions significantly decreased (-33%) compared with SD group. Neuronal cholinergic responses to EFS were significantly reduced in ileum segments of HFD mice (-57%). In NANC conditions, EFS at 10 Hz caused a slight increase (not significant) in relaxation in HFD mice. Pretreatment with 1400W, a selective inhibitor of iNOS, did not affect 10 Hz EFS-induced relaxation in NANC conditions, whereas addition of the non-selective NOS inhibitor L-NAME blocked EFS-evoked NANC relaxation in SD and HFD mice. Conclusion: HFD-induced obesity determines alterations in small intestine neuromuscular contractility and gut motility, potentially due to impairment of the excitatory pathways responsible in controlling intestinal function
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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