1,720,973 research outputs found
Esophageal left atrial pulse in mitral valve prolapse
No full textEsophageal left atrial pulse: a minimally invasive, diagnostic technique for prolapse and other abnormalities of the mitral valve
The management of viral hepatitis in CKD patients : an unresolved problem
No full textChronic kidney disease (CKD) patients in dialysis (HD) show peculiar, atypical features of clinical presentation and diseases (cardiovascular, metabolic, hematologic). This is also true for viral hepatitis infections, for which CKD patients represent an important risk group. In the past, hepatitis B virus (HBV) was the major cause of viral hepatitis in end-stage renal disease (ESRD). However, the introduction of a rigorous infection-control strategy, routine screening of patients and staff for hepatitis B serologic markers, vaccination of susceptible patients and staff, use of separate rooms and dedicated machines for HD of HbsAg-positive patients have all led to a decline in the spread of HBV infection in dialysis. Despite the prevalence of the antibody-hepatitis C virus (HCV), there has been a marked decrease in HD patients; after the introduction of routine screening for HCV and the use of erythropoietin, its occurrence ranges from 5% to 25% in the United States, with a prevalence of 6.8% in Europe. In CKD and in HD patients, the presence of HBV and HCV is an independent and significant risk factor for death and this risk may be at least partially attributed to chronic liver disease with its attendant complications. Liver disease can progress with modest hepatic inflammation and prominent fibrosis; the natural history of viral hepatitis in these patients is dependent on the immune dysfunction typical of kidney disease. Despite recent advances in antiviral therapy, there are still many uncertainties in regards to the efficacy and long-term outcomes of treatment with antiviral agents
Atrial septal aneurysm as a cardioembolic source in adult patients with stroke and normal carotid artery. A multicenter study
Full text linkBackground Atrial septal aneurysm has been considered a potential source of cardiogenic embolism for many years.The present study evaluated the prevalence and characteristicsof atrial septal aneurysm in a patient population with stroke and normal carotid arteries compared to a control population without stroke.Methods A total of 606 patients were enrolled between November 1990 and December 1996. The study group included 245 patients who had experienced cerebral ischaemic attack but had normal carotid arteries. The control group included 316 age- and sex-matched patients undergoing transoesophageal echocardiography for indications other than a search for a cardiac source of embolism. The prevalence and morphological characteristics of atrial septal aneurysm were evaluated and compared.Results We reported a higher prevalence of atrial septal aneurysm in the group with cerebral ischaemia; 68 patients (27·7%) vs 36 patients (9·9%) from the control group; P<0·001. A patent foramen ovale was detected with contrast injection in 69·2% of the patients with atrial septal aneurysm. Atrial septal aneurysm predicted the presence of a patent foramen ovale (odds ratio of patent foramen ovale 4·2; 95% CI 1·03–9·8). Multivariate analysis showed that atrial septal aneurysm was an independent predictor of an embolic event. In the 95% of patients with atrial septal aneurysm and cerebral ischaemia aged less than 45 years, transoesophageal echocardiography did not detect a source of embolism other than an associated patent foramen ovale. Conclusions The prevalence of atrial septal aneurysm inpatients with cerebral ischaemia and normal carotid arterieswas 27·7%, higher than the control group. Atrial septalaneurysm was frequently associated with patent foramenovale. In patients less than 45 years old, atrial septalaneurysm was the only potential cardiac source of embolismdetected with transoesophageal echocardiography
Frequency of atrial septal aneurysm in Patients with Recent Stroke. Preliminary resulta from a multicenter Study
Full text linkBACKGROUND: The role of atrial septal aneurysm (ASA) as a risk factor for cerebral ischemia of unknown etiology is controversial. Recent studies have found an association between ASA and focal ischemic events, while results from other studies suggest a low incidence of embolism in patients with ASA. HYPOTHESIS: The present study was designed to evaluate the frequency of ASA, a minor cardioembolic source, in patients with a recent stroke presenting with normal carotid arteries. METHODS: In all, 394 patients with cerebral ischemic stroke were referred to our institutions. Patients underwent transthracic and transesophageal echocardiography and carotid artery ultrasound examination. The study population included 215 patients without significant arterial disease. Frequency and morphologic characteristics of ASA were evaluated. RESULTS: Transthoracic examination showed ASA in 39 patients (18%), while transesophageal echocardiography showed ASA in 61 patients (28%). A patent foramen ovale was found in 47 patients (21.8%) and was associated with ASA in 40 patients (65.5%). We observed an increased thickness of the aneurysmatic wall (3.80 +/- 1.7 mm) in all patients with ASA. CONCLUSIONS: The present study confirms the relationship between ASA and stroke in patients with normal carotid arteries. The most common abnormality associated with ASA was patent foramen ovale. We suggest that patients who have a stroke in the absence of significant carotid disease undergo transesophageal echocardiography to identify possible underlying septal abnormalitiesBackground: The role of atrial septal aneurysm (ASA) as a risk factor for cerebral ischemia of unknown etiology is controversial. Recent studies have found an association between ASA and focal ischemic events, while results from other studies suggest a low incidence of embolism in patients with ASA. Hypothesis: The present study was designed to evaluate the frequency of ASA, a minor cardioembolic source, in patients with a recent stroke presenting with normal carotid arteries. Methods: In all, 394 patients with cerebral ischemic stroke were referred to our institutions. Patients underwent transthoracic and transesophageal echocardiography and carotid artery ultrasound examination. The study population included 215 patients without significant arterial disease. Frequency and morphologic characteristics of ASA were evaluated. Results: Transthoracic examination showed ASA in 39 patients (18%), while transesophageal echocardiography showed ASA in 61 patients (28%). A patent foramen ovale was found in 47 patients (21.8%) and was associated with ASA in 40 patients (65.5%). We observed an increased thickness of the aneurysmatic wall (3.80 ± 1.7 mm) in all patients with ASA. Conclusions: The present study confirms the relationship between ASA and stroke in patients with normal carotid arteries. The most common abnormality associated with ASA was patent foramen ovale. We suggest that patients who have a stroke in the absence of significant carotid disease undergo transesophageal echocardiography to identify possible underlying septal abnormalities
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
- …
