1,721,020 research outputs found
Serum kynurenic acid is lower in systemic sclerosis patients with microvascular damage of hands
No full textBackground: Endothelial dysfunction occurs early in systemic sclerosis (SSc), leading to tissue hypoxia, vasoconstriction and fibrosis. It has been demonstrated that endothelial cells (ECs) are able to produce kynurenic acid (KYNA) in response to vascular inflammation, due to its anti-inflammatory and anti-oxidants activity. In SSc patients, blood perfusion of hands, assessed by laser speckle contrast analysis (LASCA), correlated negatively with the extent of the nailfold microvascular damage, scored according to nailfold videocapillaroscopy (NVC) classification. Aim of this study was to evaluate the difference of serum KYNA in SSc patients with different stages of microvascular damage. Methods: Serum KYNA was assessed in 40 SSc patients at the enrolment. NVC was performed to evaluate capillaroscopic patterns (early, active and late). LASCA was performed to evaluate mean peripheral blood perfusion (PBP) of both hands and to evaluate the proximal-distal gradient (PDG). Results: Median PDG was significantly lower in SSc patients with late NVC pattern compared to SSc patients with early and active NVC pattern [3.79 pU (IQR −8.55–18.16) vs 23.55 pU (IQR 14.92–43.80), p < 0.01]. Serum KYNA was significantly lower in SSc patients with late NVC pattern compared to SSc patient with early and active NVC pattern [45.19 ng/mL (IQR 42.70–54.74) vs 52.65 ng/mL (IQR 49.99–60.29), p < 0.05]. Moreover, SSc patients without PDG had significantly lower serum KYNA than in SSc patients with PDG [48.03 ng/mL (IQR 43.87–53.68) vs 59.27 ng/mL (IQR 49.15–71.00), p < 0.05]. Conclusion: KYNA is lower in SSc patients with late NCV pattern and without PDG. KYNA may be associated with early endothelial dysfunction
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
In systemic sclerosis TAPSE/sPAP ratio is correlated with ventilatory efficiency and exercise capacity assessed by CPET
No full textObjectives: The aim of the study was to evaluate the correlation between cardiopulmonary exercise testing (CPET) parameters and right ventricular echocardiographic parameters for pulmonary arterial hypertension screening in a cohort of systemic sclerosis (SSc) patients. Methods forty SSc patients were examined using CPET and resting transthoracic echocardiography. CPET parameters analyzed were minute ventilation/carbon dioxide production (VE/VCO2) slope and maximum oxygen uptake (VO2 max); echocardiographic parameters were systolic pulmonary artery pressure (sPAP), tricuspid annular plane systolic excursion (TAPSE), and TAPSE/sPAP ratio. Results a positive correlation was observed between VE/VCO2 slope and age (r = 0.415, p < 0.01) and sPAP (r = 0.461, p < 0.01), conversely, a negative correlation was found between VE/VCO2 slope and TASPE/sPAP ratio (r = − 0.521, p = 0.001). VO2 max showed an inverse correlation with age (r = − 0.367, p < 0.05) and sPAP (r = − 0.387, p < 0.05) and a positive correlation with TAPSE/sPAP ratio (r = 0.521, p < 0.01). On stepwise linear regression analysis, VE/VCO2 slope was significantly correlated with TAPSE/sPAP ratio (β coefficient = − 0.570; p < 0.0001), as well as VO2 max was significantly correlated with TAPSE/sPAP ratio (β coefficient = 0.518; p = 0.001). Conclusion in SSc patients, TAPSE/sPAP ratio is the echocardiographic parameter of RV function which showed the best correlation with ventilatory efficiency and exercise capacity
IL33 and sST2 serum level in systemic sclerosis microvascular involvement
No full textAim: Endothelial dysfunction and microvascular damage are hallmarks of systemic sclerosis (SSc). Objective of this study was to evaluate IL33 and ST2 serum levels in SSc patients and healthy controls (HC). Secondary aim was to evaluate the IL33 axis in the SSc microvascular manifestation. Methods: IL33 and sST2 have been assessed in 46 SSc patients and 24 HC matched for sex and age. Main clinimetric indexes were assessed. Skin perfusion of hands was evaluated by Laser Speckle Contrast Analysis (LASCA) and echocolordoppler ultrasound of renal arteries was performed to evaluate subclinical renal involvement. Results: SSc patients had higher serum level of IL33 and sST2 than HC. IL33 and sST2 were significantly higher in SSc patient with digital ulcers (DUs) compared to SSc patients without DUs. SSc patients with late nailfold videocapillaroscopy (NVC) pattern had higher serum levels of sST2 than SSc patients with active NVC pattern. SSc patients without proximal-distal gradient (PDG) at LASCA had significantly higher sST2 serum level compared to SSc patients with PDG. SSc patients with renal resistive index (RRI) ≥ 0.70 had higher serum levels of sST2 than SSc patients with RRI < 0.70. A positive linear correlation was shown between sST2 and RRI, between sST2 and intrarenal S/D and between sST2 and PI. Kaplan-Meier curves show a significantly reduced free survival from DUs in patients with increased sST2 (p = 0.025). In multivariate analysis, sST2 is associated with the development of new DUs. Conclusion: IL33 and sST2 are increased in SSc patients and ST2 might be a marker of microvascular damage
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
- …
