1,720,957 research outputs found
Transcriptional regulation of tenascin genes
Get PDFExtracellular matrix proteins of the tenascin family resemble each other in their domain structure, and also share functions in modulating cell adhesion and cellular responses to growth factors. Despite these common features, the 4 vertebrate tenascins exhibit vastly different expression patterns. Tenascin-R is specific to the central nervous system. Tenascin-C is an "oncofetal" protein controlled by many stimuli (growth factors, cytokines, mechanical stress), but with restricted occurrence in space and time. In contrast, tenascin-X is a constituitive component of connective tissues, and its level is barely affected by external factors. Finally, the expression of tenascin-W is similar to that of tenascin-C but even more limited. In accordance with their highly regulated expression, the promoters of the tenascin-C and -W genes contain TATA boxes, whereas those of the other 2 tenascins do not. This article summarizes what is currently known about the complex transcriptional regulation of the 4 tenascin genes in development and disease
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
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
Characterization of tenascin-W, an emerging player in the metastatic bone marrow niche
Get PDFTumors are heterogeneous organ-like tissues including not only tumor cells themselves but also auxiliary cells such as, endothelial cells, fibroblasts, inflammatory cells, and bone marrow derived stem or stromal cells (BMSCs), which collectively create the surrounding microenvironment also referred to as stromal compartment. By now the active role of the tumor-stroma in driving the dissemination phase and the following engraftment of tumor cells in secondary organs is widely accepted. Indeed, the perpetual activation of stromal cells is extended beyond the local primary tumors and they can take part in preparing a permissive environment at distant anatomic sites by providing oxygen and nutrients essential for tumor growth and invasion.
Tenascin-W (TNW) is a matricellular protein with a dynamically changing pattern of expression during development and disease. Its pronounced presence in developing bones implies a function in osteogenesis. In adults, tenascin-W is mostly restricted to stem cell niches, and is also expressed in the microenvironment of solid cancers. These distinct expression patterns imply a complex regulation of tenascin-W gene expression at the transcriptional level. Here we analyzed tenascin-W expression in a xenograft model of breast cancer metastasis to the bone. Quantitative mRNA analysis revealed an upregulation of tenascin-W in mouse osteoblast populations sorted from bones harboring human breast cancer metastases. Long bone sections containing metastases exhibit expression of mouse tenascin-W protein proving that tenascin-W is supplied by the metastatic niche and not by the tumor cells. Transwell and co-culture studies show that bone marrow stem cells (BMSCs) express tenascin-W protein after exposure to factors secreted by MDA-MB231-1833 breast cancer cells. These findings prompted us to investigate the cis and trans-acting elements that drive tenascin-W . 5’RAC analysis of mRNA from human breast cancer, glioblastoma, and bone tissue showed a single tenascin-W transcript with a transcription start site (TSS) at a non-coding first exon upstream of exon2, which contains the translation start codon (ATG). The promoter region between -957bp and -79bp influences transcription and the minimal promoter sequence is contained within 79bp from the TSS. Computational analysis shows the presence of Smad4 nuclear transcription factor binding site at -61bp from the TSS in proximity of a TATA box sequence. Site-directed mutagenesis of the Smad4-binding site strongly impaired the SEAP reporter gene expression driven by the basal promoter. Furthermore, we found three evolutionary conserved regions in the first intron harboring glucocorticoid response elements (GRE), which negatively affect
10 I. Summary
transcription initiation from the basal promoter (-79bp). Therefore, we assessed whether TGF1 and glucocorticoids (GCs) act on tenascin-W gene expression in the tumor context. We identified TGF1 as an important factor inducing human tenascin-W gene transcription in BMSCs through activation of ALK5. Preincubation of BMSCs with the ALK5 inhibitor, SB431542, abolished tenascin-W induction by TGF1. Moreover, GCs impaired tenascin-W mRNA expression in BMSCs. Finally, recombinant tenascin-W protein stimulated MDA-MB231-1833 cell proliferation and migration in vitro assays. Our experiments suggest that tenascin-W acts as a niche component for breast cancer metastasis to the bone by supporting cell migration and cell proliferation of the breast cancer cells.
The analysis of the tumor bed contribution to cancer progression is a new frontier to unravel. It will lead to novel approaches to interfere with mechanism implicated in drug resistance, tumor relapse and metastatic spread
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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