1,720,954 research outputs found
Renal dysfunction is a confounder for plasma natriuretic peptides in detectingheart dysfunction in uremic and idiopathic dilated cardiomyopathies.
No full textClin Chem. 2007 Dec;53(12):2097-104. Epub 2007 Oct 12.
Renal dysfunction is a confounder for plasma natriuretic peptides in detecting heart dysfunction in uremic and idiopathic dilated cardiomyopathies.
Codognotto M, Piccoli A, Zaninotto M, Mion M, Plebani M, Vertolli U, Tona F, Ruzza L, Barchita A, Boffa GM.
Source
Division of Nephrology, University Hospital, University of Padova, Italy.
Abstract
BACKGROUND:
The diagnostic value of natriuretic peptides in uremic cardiomyopathy has not been defined, nor has the effect of a hemodialysis (HD) session on peptides.
METHODS:
We performed an observational study of 100 white adult outpatients in New York Heart Association class I-II, with neither diabetes nor ischemic heart disease, 50 of whom had idiopathic dilated cardiomyopathy (DCM) and 50 of whom had uremic cardiomyopathy and were undergoing HD. We measured plasma N-terminal proB-type natriuretic peptide (NT-proBNP), BNP, and atrial natriuretic peptide (ANP) both before and after a dialysis session. Doppler echocardiograms were evaluated. We performed multiple regression analysis on the logarithm of peptide concentrations using clinical, laboratory, and echocardio-Doppler data as explanatory variables.
RESULTS:
Mean peptide concentrations were higher in the HD group, with an HD:DCM ratio of 25 for NT-proBNP and 5 for BNP and ANP. Peptides were correlated with each other (r > 0.85). After HD, NT-proBNP significantly increased by 14%, BNP decreased by 17%, and ANP decreased by 56%. Predialysis concentrations correlated with postdialysis values (r > 0.85). A multiple regression equation significantly fitted the observed peptide concentrations, both pre- and postdialysis, using the same set of 4 variables: disease group (DCM or HD), diastolic pattern, left atrial volume, and body mass index.
CONCLUSIONS:
Renal dysfunction was a confounder for natriuretic peptides, which were present in higher concentrations in the uremic patients with milder cardiac dysfunction than in those with idiopathic DCM without renal dysfunction. Left diastolic function pattern and atrial volume were cardiac determinants of peptide concentrations in DCM and HD
Effect of a dialysis session on the prognostic values of NT-proBNP, troponins, endothelial damage and inflammation biomarkers
No full textAbstract
BACKGROUND: In hemodialysis, the relationship between the increased concentration of natriuretic peptides and volume overload, inflammatory activity, endothelial dysfunction, left ventricular function and mass, and silent ischemic events is not clear. To investigate the relationship, a 3-year prospective cohort study was conducted in 50 adult hemodialysis patients in NYHA class I-II who were free from diabetes and ischemic heart events.
METHODS: Doppler echocardiogram, plasma NT-proBNP, troponin T and I, CRP, TNF alpha, big-endothelin 1, and cystatin-C, were determined both before and after a dialysis session. The outcome was all-cause death.
RESULTS: 13 out of 50 patients died. Survival curves significantly differed by age (above vs. below the median 68 yrs), NT-proBNP (9719 pg/mL), troponin T (0.03 ng/mL), C-reactive protein (4.8 mg/L), left atrial volume index (51 mL/sqm), ejection fraction (61%), and diastolic pattern. In the Cox model only NT-proBNP (cutoff 10000 pg/mL) had a significant hazard ratio (4.1). Post-HD measurements of NT-proBNP, troponin T, and CRP maintained their prognostic value. The high correlation between pre and post values of NT-proBNP, and the lack of correlation with ultrafiltration volume excluded a role for acute fluid removal on its regulation.
CONCLUSIONS: The increased level of NT-proBNP is the most important prognostic factor even in the absence of severe heart dysfunction and myocardial ischemic events, without any relationship with endothelial dysfunction, inflammatory biomarkers, or with acute fluid removal. A cutoff value of NT-proBNP of 10000 pg/mL could be used to identify hemodialysis patients with a higher risk of death
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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