1,720,976 research outputs found
Dupuytren’s Disease of the hand. The potential for reducing fibrosis using 5-Fluorouracil.
Get PDFDupuytren's disease is a progressive fibroproliferative disorder leading to reduced hand function. The main treatment is surgical correction but post-operative recurrence is high. Dupuytren's is characterised by palmar and digital nodules and cords with increased myofibroblast proliferation and excessive extracellular matrix production. Review of the literature establishes that transforming growth factor β-1 (TGFβ-1) has been shown to increase myofibroblast differentiation, fibroblast proliferation and extracellular matrix production acting via an autocrine loop. 5-fluorouracil (5-fu) has been reported to reduce fibroblast proliferation and differentiation in vitro and to reduce adhesion formation in a tendon injury animal model. The hypothesis tested in this project was that 5-fu would reduce the profibrotic characteristics of fibroblasts in culture. 5-fu could therefore reduce the postoperative recurrence rates in Dupuytren's disease. The investigation would require the establishment of the following cell cultures, tendon and Dupuytren's from nine and 12 subjects respectively. Total collagen synthesis was investigated by measuring the incorporated radioisotope, tritiated proline, in collagenase digestible samples. It was found that total collagen synthesis was specifically and selectively reduced by 5-fu compared with non-collagenous protein synthesis when fibroblasts were incubated with or without exogenous TGFβ-1. Gene expression for collagen types I and III was measured by RT-PCR. Basal collagen type III expression was found to be increased compared with collagen type I expression for both control and Dupuytren's fibroblasts. Basal collagen type III expression was increased for Dupuytren's compared with control fibroblasts. Pre-treatment with 5-fu did not induce a reduction in gene expression for collagen types I and III compared with vehicle control treated cells. TGFβ-1 secretion was assessed by a sandwich ELISA. TGFβ-1 secretion was found to be increased by fibroblasts from Dupuytren's compared with controls. Pre-treatment with 5-fu did not induce a reduction in TGFβ-1 secretion. Gene expression for collagen and TGFβ-1 was measured by reverse transcription-polymerase chain reaction. Basal TGFβ-1 gene expression was found to be increased in Dupuytren's fibroblasts compared with controls. A double blind prospective randomised clinical trial investigating the effect of 5-fu in reducing post-operative recurrence rates in Dupuytren's disease has been established by the author. Experience to date has shown that 5-fu has not caused a delay in wound healing. 5-fu treatment did not adversely affect the early (up to six months) surgical outcome when compared with control treated digits. The clinical picture regarding recurrence rates will become clearer with increased length of follow-up and number of patients. The transition has therefore been made from in vitro investigation to commencing a prospective randomised controlled clinical trial
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
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