1,720,990 research outputs found
Recurrent syncope on effort due to concealed constrictive pericarditis.
No full textA 69-year-old male patient was admitted for two syncopal episodes on effort associated with dyspnoea and jugular constrain. Clinically, he was found to have mild bilateral pleural effusion, jugular vein distension, and marked peripheral oedema. Echocardiographic examination showed a leftward interventricular septum during peak inspiration owing to the increasing right ventricle pressure (Figure 1A) and a dilation (27 mm) and absent collapse of the inferior vena cava and hepatic veins (Figure 1B). Ventriculography does not reveal calcifications of the pericardium (Figure 1C). At the invasive haemodynamic evaluation, simultaneous right and left catheterization showed the square root sign of LV diastolic pressure trackings and equalization of LV and RV diastolic plateau pressure tracking. Magnetic resonance images (coronal T1-weighted FSE sequence image; Harmony, Siemens, Erlangen, Germany) showed the thickened pericardium (>5 mm) with irregular margins (white arrows) (Figure 1D). After administration of contrast media, the late acquisitions revealed diffuse and homogeneous hyperintense pericardium (white arrows) (Figure 1E and F; a, left ventricle; b, right ventricle). An endomyocardial biopsy was performed and excluded associated restrictive myocardial diseases. A diagnosis of constrictive pericarditis was put forward and the patient underwent pericardiectomy. Surgical pathology examination of the resected pericardium revealed, at gross examination, a diffuse severe fibrous thickening (Figure 2A). At histology, multiple foci of chronic inflammation (lymphocytes and plasma cells) are detected associated only with mild calcification (Figure 2B, haematoxylin–eosin ×40; and Figure 2C, B-lymphocytes CD20; Figure 2D, T-lymphocytes CD3; Figure 2E, macrophages CD68; Figure 2F, plasma cells CD79a; Figure 2G, cytotoxic T-lymphocytes CD8, all magnification ×160).
Initially, the constrictive pericarditis was concealed because of the coexistence of equivocal clinical symptoms. Because of sleeping troubles, a diagnosis of mild constrictive pulmonary disease together with obstructive sleep apnoea syndrome was put forward. An electroencephalogram was performed suggesting focal epilepsy and valproic acid therapy was undertaken. The patient was discharged home 7 days after surgery. Nowadays, he is able to practice a light mountain-bike activity
Real-time three-dimensional transthoracic echocardiographic visualisation of accessory mitral valve tissue in a 22-year-old man with multiple sclerosis.
No full textCardiovascular Clinical Risk constrains to a powerful primary prevention: Carotid atherosclerosis in toto and low dose computed tomography coronary angiography?
No full textCurrent interpretation of myocardial stunning
No full textMyocardial stunning is a temporary post-ischemic cardiac mechanical dysfunction. As such, it is a heterogeneous entity and different conditions can promote its occurrence. Transient coronary occlusion, increased production of catecholamines and endothelin, and myocardial inflammation are all possible causes of myocardial stunning. Possible underlying mechanisms include an oxyradical hypothesis, calcium overload, decreased responsiveness of myofilaments to calcium, and excitation-contraction uncoupling due to sarcoplasmic reticulum dysfunction. The aim of this review is to summarize the clinical conditions that may be responsible for stunned myocardium
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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