1,721,075 research outputs found
Differences in plaque morphology and correlation of stenosis at the carotid artery bifurcation and the carotid siphon
No full textOBJECTIVE. The purpose of this study was to compare the type of plaque and the degree of stenosis in the carotid artery bifurcation and the carotid siphon to explore potential correlations between these parameters. MATERIALS AND METHODS. A total of 119 patients (87 men, 32 women; mean age, 69 years) were retrospectively studied using MDCT angiography. Component types of the carotid artery bifurcation and the carotid siphon plaque were defined according to attenuation values, and the volumes of each plaque component were calculated. The degree of stenosis was calculated according to the North American Symptomatic Endarterectomy Trial method. Data were compared using the Wilcoxon signed-rank test, Spearman correlation analysis, and receiver operating characteristic (ROC) analysis. RESULTS. The results of the Wilcoxon test showed a statistically significant difference (p = 0.0001) between the degree of stenosis at the carotid artery bifurcation and that at the carotid siphon. We observed a statistically significant difference (p = 0.0001) between the total volumes of the carotid artery bifurcation (mean value, 748 mm(3)) and the carotid siphon (mean value, 54 mm(3)) plaque. Moreover, the respective mean percentages of calcified, mixed, and lipid components of plaque were 17%, 56%, and 27% in the carotid artery bifurcation and 73%, 19%, and 8% in the carotid siphon, showing a statistically significant difference (p = 0.001). ROC analysis did not show association between carotid siphon plaque volume and previous cerebrovascular events (Az = 0.562; p = 0.149), whereas the total volume of the carotid artery bifurcation plaque-and, in particular, the volume of the lipid components-showed a statistically significant association (Az = 0.691, and Az = 0.758; p < 0.001). CONCLUSION. No significant association was found between presence of mixed and fatty components of plaque in the carotid artery bifurcation and presence of similar components in the carotid siphon. The carotid artery bifurcation total plaque volume (and, in particular, carotid artery bifurcation lipid volume) was associated with previous cerebrovascular events, whereas no association with the volume of carotid siphon plaque (and its subcomponents) was foun
Infarct-like myocarditis with coronary vasculitis and aneurysm formation caused by epstein–barr virus infection
Full text linkMyocardial infection by Epstein–Barr virus (EBV) may manifest with inflammatory cardiomyopathy, coronary syndrome X, and rarely with infarct-like myocarditis. The aim of the report is to describe a case of myocardial EBV infection causing acute myocarditis with heart failure, necrotizing coronary vasculitis, and multiple left ventricular (LV) aneurysms. A 67-year-old woman presented with fever, chest pain, and heart failure. She underwent non-invasive cardiac studies including electrocardiography, 2D-echocardiography, cardiac magnetic resonance, hematochemical exams with Troponin T determination, and invasive studies including cardiac catheterization, coronary angiography, and LV endomyocardial biopsy. Five endomyocardial samples were processed for histology and immunohistochemistry for inflammatory cells characterization and detection of viral antigens. Two additional frozen samples were evaluated by real-time polymerase chain reaction for the presence of cardiotropic viral genomes. Routine laboratory tests revealed the presence of elevated white blood cells (17 000 103/μL) and increased Troponin T. Electrocardiogram showed sinus tachycardia with ST elevation in V2–V5. Two-dimensional echocardiography showed normal LV dimension with reduced LV contractility (LVEF = 40%) with mild pericardial effusion. Cardiac magnetic resonance revealed the presence of a micro-aneurism in the inferior LV wall, a diffuse oedematous imbibition of LV myocardium suggested by hyper-intensity of T2 mapping, and increased fibrosis as suggested by areas of late gadolinium enhancement signals. Coronary arteries were normal while several micro-aneurysms were observed at LV angiography. At histology, a lymphocytic myocarditis with necrotizing coronary vasculitis sustained by a positive real-time polymerase chain reaction for EBV, detectable in cardiomyocytes and inflamed intramural vessels by positive immunohistochemistry for EBV latent membrane protein 1 antigen, was observed. Myocardial EBV infection is an unusual cause of acute heart failure and cardiac aneurysms, increasing the risk of electrical instability, cardiac perforation, and sudden death
Sinus of Valsalva aneurysm with obstruction of right ventricular outflow tract
No full text[No abstract available
Differences in plaque morphology and correlation of stenosis at the carotid artery bifurcation and the carotid siphon
No full textOBJECTIVE. The purpose of this study was to compare the type of plaque and the degree of stenosis in the carotid artery bifurcation and the carotid siphon to explore potential correlations between these parameters. MATERIALS AND METHODS. A total of 119 patients (87 men, 32 women; mean age, 69 years) were retrospectively studied using MDCT angiography. Component types of the carotid artery bifurcation and the carotid siphon plaque were defined according to attenuation values, and the volumes of each plaque component were calculated. The degree of stenosis was calculated according to the North American Symptomatic Endarterectomy Trial method. Data were compared using the Wilcoxon signed-rank test, Spearman correlation analysis, and receiver operating characteristic (ROC) analysis. RESULTS. The results of the Wilcoxon test showed a statistically significant difference (p = 0.0001) between the degree of stenosis at the carotid artery bifurcation and that at the carotid siphon. We observed a statistically significant difference (p = 0.0001) between the total volumes of the carotid artery bifurcation (mean value, 748 mm3) and the carotid siphon (mean value, 54 mm3) plaque. Moreover, the respective mean percentages of calcified, mixed, and lipid components of plaque were 17%, 56%, and 27% in the carotid artery bifurcation and 73%, 19%, and 8% in the carotid siphon, showing a statistically significant difference (p = 0.001). ROC analysis did not show association between carotid siphon plaque volume and previous cerebrovascular events (Az = 0.562; p = 0.149), whereas the total volume of the carotid artery bifurcation plaque - and, in particular, the volume of the lipid components - showed a statistically significant association (Az = 0.691, and Az = 0.758; p < 0.001). CONCLUSION. No significant association was found between presence of mixed and fatty components of plaque in the carotid artery bifurcation and presence of similar components in the carotid siphon. The carotid artery bifurcation total plaque volume (and, in particular, carotid artery bifurcation lipid volume) was associated with previous cerebrovascular events, whereas no association with the volume of carotid siphon plaque (and its subcomponents) was found. © American Roentgen Ray Society
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
- …
