1,720,958 research outputs found
Role of oxidative and nitrosative stress biomarkers in chronic heart failure
No full textIn this review, we present recent insights on chronic heart failure (CHF) and the potential role of tumor necrosis factor (TNF)-alpha, interleukins, myeloperoxidase (MPO), and nitrosative stress in the progression of this disease process. Reactive oxygen species (ROS) are produced as a consequence of aerobic metabolism. Under physiologic conditions, their unfavourable effect in causing oxidative damage is counteracted by antioxidants. An imbalance in favour of oxidants leads to oxidative stress, and contributes to myocyte apoptosis, direct negative inotropic effects, and reduced bioavailability of nitric oxide (NO). Together, these effects lead to impaired vasodilatation of the coronary, pulmonary and peripheral vascular beds. In patients with moderate to severe forms of CHF, TNF-alpha leads to the formation of nitrotyrosine and consumption of nitric oxide by virtue of activation of myeloperoxidase. Further studies are required to better elucidate the complex interaction of oxidative stress, endothelial dysfunction and inflammatory activation in CHF. Such insights would likely lead to development of better strategies for the assessment of the disease severity by monitoring of new bio-humoral indices and better treatment approaches
Flow-mediated dilation normalization predicts outcome in chronic heart failure patients.
No full textBackground: Reduced flow-mediated dilation (FMD) is a known prognostic marker in heart failure (HF), but may be influenced by the brachial artery (BA) diameter. Aiming to adjust for this influence, we normalized FMD (nFMD) by the peak shear rate (PSR) and tested its prognostic power in HF patients. Methods and Results: BA diameter, FMD, difference in hyperemic versus rest brachial flow velocity (FVD), PSR (FVD/BA), and nFMD (FMD/PSR × 1000) were assessed in 71 HF patients. At follow-up (mean 512 days), 19 HF (27%) reached the combined endpoint (4 heart transplantations [HTs], 1 left ventricle assist device implantation [LVAD], and 14 cardiac deaths [CDs]). With multivariate Cox regression analysis, New York Heart Association functional class ≥III (hazard ratio [HR] 9.36, 95% confidence interval [CI] 2.11-41.4; P =.003), digoxin use (HR 6.36, 95% CI 2.18-18.6; P =.0010), FMD (HR 0.703, 95% CI 0.547-0.904; P =.006), PSR (HR 1.01, 95% CI 1.005-1.022; P =.001), FVD (HR 1.04, 95% CI 1.00-1.06; P =.02), and nFMD (HR 0.535, 95% CI 0.39-0.74; P =.0001) were predictors of unfavorable outcome. Receiver operating characteristic curve for nFMD showed that patients with nFMD >5 seconds had significantly better event-free survival than patients with nFMD ≤5 seconds (log-rank test: P 5 seconds have a better prognosis than those with lower values
INCREASED NITROTYROSINE PLASMA LEVELS IN RELATION TO SYSTEMIC MARKERS OF INFLAMMATION AND MYELOPEROXIDASE IN CHRONIC HEART FAILURE.
No full textThe presence of a reciprocal link between inflammation and oxidative/nitrosative stress has been postulated in chronic heart failure
(CHF). We aimed to determine signs of nitrosative stress in serum/plasma of CHF patients.
ELISA tests were used for quantification of serum/plasma levels of Nitrotyrosine (NT), H2O2, total NO, nitrite (NO2
−), myeloperoxidase
(MPO), Tumor Necrosis Factor-alpha (TNFα) and pro-Brain Natriuretic Peptide (proBNP) in 66 CHF patients (9 in NYHA I, 34 NYHA II,
23 NYHA III) and in 14 age-matched healthy subjects. NT levels were higher in NYHA III CHF patients compared to NYHA II (pb0.05),
NYHA I (pb0.03) and controls (pb0.02), whereas NO2
− and total NO were higher in NYHA III compared to I (pb0.05 and pb0.04,
respectively) and controls (pb0.004 and 0.002) and in NYHA II compared to controls (pb0.04 and pb0.009). NT levels correlated
significantly with MPO (r=0.37, pb0.003), TNFα (r=0.32, pb0.01) and proBNP (r=0.32, pb0.01). These data demonstrate an increased
NT plasma level in patients with moderate/severe CHF which is associated to increased levels of markers of systemic inflammation
Prognostic relevance of a non-invasive evaluation of right ventricular function and pulmonary artery pressure in patients with chronic heart failure.
No full textAIM:
To determine the prognostic relevance of the echocardiographic evaluation of pulmonary artery systolic pressure (PASP) and tricuspid annular plane systolic excursion (TAPSE) in patients with chronic heart failure (CHF). Pulmonary hypertension (PH) and right ventricular (RV) dysfunction have both been associated with poor prognosis in CHF.
METHODS AND RESULTS:
A complete echocardiographic examination was performed in 658 outpatients with CHF and LVEF <45%. PASP was available in 544 (83%) patients, TAPSE in all patients, and E wave deceleration time (DT) in 643 (98%) patients. During a median follow-up period of 38 months, 125 patients died, 5 underwent urgent heart transplantation, and 5 had an appropriately detected and treated episode of ventricular fibrillation. At Cox survival analysis (composite endpoint was death, urgent heart transplantation, and ventricular fibrillation), patients with PASP ≥40 mmHg plus TAPSE ≤14 mm had a poorer prognosis than those with high PASP but preserved TAPSE; RV dysfunction associated with normal PASP did not carry additional risks. Similar results were obtained when patients were grouped on the basis of DT (restrictive vs. non restrictive) and TAPSE.
CONCLUSIONS:
A simple echocardiographic evaluation of PASP and RV function with TAPSE may improve risk stratification in patients with CHF. Importantly, if PASP cannot be recorded at echocardiography, a restrictive DT, measurable in the vast majority of patients, may be coupled with TAPSE to stratify patients
Fibrosis markers and CRIM1 increase in chronic heart failure of increasing severity.
Full text linkBackground: Fibrosis suppressors/activators in chronic heart failure (CHF) is a topic of investigation. Aim: To quantify serum levels of fibrosis regulators in CHF. Methods: ELISA tests were used to quantify fibrosis regulators, procollagen type-(PIP)I, (PIP)III, collagen-I, III, BMP1,2,3,7, SDF1α, CXCR4, fibulin 1,2,3, BMPER, CRIM1 and BAMBI in 66 CHF (NYHA class I, n=9; II, n=34; III n=23), and in 14 controls. Results: In CHF, TGFβR2, PIPIII, SDF1α and CRIM1 were increased. PIPIII correlated with CRIM1. Conclusions: The BMPs inhibitor CRIM1 is increased and correlates with higher levels of serum PIPIII showing an imbalance in favor of pro-fibrotic mechanisms in CHF. © 2014 Informa UK Ltd. All rights reserved: reproduction in whole or part not permitted
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
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