1,721,629 research outputs found
Long-term protective effect of UR-12670 after warm renal ischemia in uninephrectomized rats
No full textLong-term protective effect of UR-12670 after warm renal ischemia in uninephrectomized rats.BackgroundThe phospholipid platelet-activating factor (PAF) participates in the pathogenesis of renal ischemia/reperfusion injury, and in vitro, it induces synthesis of extracellular matrix proteins by mesangial and tubular epithelial cells. This study investigated the long-term effects of the potent orally active PAF antagonist UR-12670 in warm ischemic uninephrectomized rats, which was given according to different therapeutic schedules.MethodsUninephrectomized male Sprague-Dawley rats were divided into five groups and were followed for 52 weeks: rats without ischemia (SK); ischemic kidney for 60 minutes (SIK); ischemic kidney and UR-12670 from 0 to the 7th day (UR 0-7); ischemic kidney and UR-12670 from day 0 to 52 weeks (UR 0-E); and ischemic kidney and UR-12670 from day 8 to week 52 (UR 8-E). Two more groups (ischemic and UR treated) served to evaluate the UR-12670–protective effect on ischemic acute renal failure at one week.ResultsUR-12670 administration exerted functional and morphological protection against post-ischemic acute renal failure. The ischemic untreated (SIK) group developed progressive proteinuria from week 12. The onset of proteinuria in ischemic UR-12670–treated groups was delayed to the 24th week, and it was significantly lower than in SIK group throughout the study. Only SIK and ischemic-treated UR 0-7 rats presented with chronic renal failure, as shown by creatinine, creatinine clearance, glomerular filtration rate (GFR), and renal plasma flow (GFR 52 weeks: SK, 2525 ± 267; SIK, 992 ± 149; UR 0-7, 1551 ± 385 μl/min). Kidneys from the short-term treated group (UR 0-7) showed a reduction of glomerulosclerosis (SK, 14.4 ± 3.7; SIK, 75.7 ± 7.7; UR 0-7, 41.5 ± 8.5%) and vascular myointimal hyperplasia, but the tubulointerstitial damage (tubulointerstitial score: SK, 0.2 ± 0.2; SIK, 4.4 ± 0.5; UR 0-7, 3.7 ± 0.7) was similar to that in the ischemic untreated group. Long-term ischemic treated rats (UR 0-E, UR 8-E) did not develop chronic renal failure (GFR: UR 0-E, 2059 ± 314; UR 8-E, 2410 ± 208 μl/min). In these groups, glomerulosclerosis (UR 0-E, 32.8 ± 5.8; UR 8-E, 24.3 ± 3.0%), tubulointerstitial damage (tubulointerstitial score: UR 0-E, 2.1 ± 0.5; UR 8-E, 1.9 ± 0.3) and vascular myointimal hyperplasia were significantly lower than in the ischemic untreated group. By in situ hybridization, an increase of transforming growth factor-β1 mRNA expression in glomerular and tubular cells was observed in ischemic untreated and ischemic treated UR 0-7 rats. UR-12670 long-term treated rats showed a clear reduction of transforming growth factor-β1 mRNA-positive glomerular cells.ConclusionThe chronic administration of the PAF antagonist UR-12670 attenuates the long-term effects of ischemia-reperfusion injury in uninephrectomized rats. The beneficial effect of this agent, even when given beyond the initial ischemia/reperfusion injury, suggests that PAF plays a role in the mechanisms of progression to late renal damage in this model
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
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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