1,720,955 research outputs found
Trefoil Factor 1 is involved in gastric cell copper homeostasis
No full textTrefoil Factor 1 belongs to a group of small secreted proteins (the Trefoil Factor Family proteins), that arelocalized within the mucous granules and are expressed and secreted by epithelial cells that line mucousmembranes. Trefoil factors are mainly expressed in the gastrointestinal tract, where they normally con-tribute to maintain the integrity of the mucosa. We recently demonstrated a selective binding abilityof Trefoil Factor 1 for copper ions, through its carboxy-terminal tail, and we also observed that copperlevels influence the equilibrium between the monomeric and homodimeric forms of Trefoil Factor 1, thus modulating its biological activity. Here we report that transcriptional regulation of Trefoil Factor 1 is also affected by copper levels, through the modulated binding of the copper-sensing transcription factor Sp1 onto the responsive elements present in the regulatory region of the gene. In addition we demonstrate that copper overload causes an accumulation of the trefoil protein in the Trans-Golgi Network and that Trefoil Factor 1 levels can influence copper excretion and copper related toxicity. These findings suggest that the protein might play a role in the overall complex mechanisms of copper homeostasis in the gastrointestinal tissues
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
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
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
Regolazione epigenetica dell’espressione del fattore peptidico gastrointestinale TFF1
Full text link2014 - 2015TFF1 is a protein expressed in the gastrointestinal tract, belonging to the trefoil folding factor family, characterized by a conserved “trefoil domain” containing six cysteine residues that form a cloverleaf disulfide structure. TFF1 is able to bind copper in vitro, favoring its homodimerization. TFF1 plays a key role in the correct formation of the mucous layer, promotes the epithelial restitution after injury and protects the integrity of the epithelial barrier. Its expression is regulated by epigenetic mechanisms such as histone modifications and DNA methylation. Altered gene expression in different pathologies is often associated with an altered DNA methylation pattern of TFF1 promoter, while histone modifications are essential in activating TFF1 transcription mediated by estrogen stimulation. Furthermore, TFF1 secreted in the gastric mucus layer may act as docking site for H. pylori adhesion on mucosal surface and it was demonstrated that the infection induces aberrant methylation correlated with gastric cancer risk.
This project is aimed at investigating the role of the epigenetic control on the TFF1 gene promoter, particularly DNA methylation. The conditions of high resolution melting method were optimized in order to evaluate the differential state of methylation of several CGs on the promoter region of tff1 in different experimental conditions. The study was mainly focused on the involvement of TFF1 in neoplastic processes and inflammatory diseases, as gastric cancer and H. pylori infection, in order to gain insight into the pathogenic mechanisms and provide useful tools to interfere and slowing down the disease progression.
Moreover, further attention is dedicated to the ongoing study regarding the effects of copper on transcriptional regulation of TFF1 and epigenetic modifications. It was demonstrated that TFF1 expression is regulated by copper and that the transcription factor Sp1 is involved in this metal-mediated regulation of transcription. Copper is not able to affect TFF1 promoter methylation in copper overload conditions. This was demonstrated with a method of High Resolution Melting which was assessed on TFF1 promoter and validated. Deep analysis on TFF1 promoter methylation status let us find out a minimum region responsible for TFF1 expression regulation by DNA methylation.
Concernig H. pylori, we focused on the early step of the infection to study the role of TFF1 using two cell models with different features and TFF1 expression: we lighted up alterations of TFFs, inflammatory cyitokines and EMT markers, that were differentially induced or repressed in the two different cell lines. Furthermore an altered methylation of TFF1 and genes involved in Wnt pathway emerged. [edited by author]XIV n.s
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