1,720,960 research outputs found
Complex and extensive infective endocarditis: a novel surgical approach
No full textEndocarditis involving the central fibrous body of the heart requires carefully planned surgical intervention. We present a novel approach in a 65-year-old male with extensive endocarditis involving the aortic root, ventricular septum, central fibrous body together with mitral, aortic and tricuspid valves
A prospective randomized study to evaluate the renoprotective action of beating heart coronary surgery in low risk patients
No full textObjectives: cardiopulmonary bypass (CPB) is widely regarded as an important contributor to renal failure, a well recognized complication following coronary artery surgery (coronary artery bypass grafting (CABG)). Anecdotally off-pump coronary surgery (OPCAB) is considered renoprotective. We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass (ONCAB). Methods: forty low-risk patients with normal preoperative cardiac and renal functions awaiting elective CABG were prospectively randomized into those undergoing OPCAB (n=20) and ONCAB (n=20). Glomerular and tubular injury were measured respectively by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to creatinine (Cr). Daily measurements were taken from admission to postoperative day 5. Fluid balance, serum Cr and blood urea were also monitored. Results: no mortality or renal complication were observed. Both groups had similar demographic makeup, Parsonnet score, functional status and extent of coronary revascularization (2.1±1.0 vs. 2.5±0.7 grafts; P=0.08). Serum Cr and blood urea remained normal in both groups throughout the study. A significant and similar rise in urinary RBP:Cr occurred in both groups peaking on day 1 (3183±2534 vs. 4035±4079; P=0.43) before reapproximating baseline levels. These trends were also observed with urinary microalbumin:Cr (5.05±2.66 vs. 6.77±5.76; P=0.22). Group B patients had a significantly more negative fluid balance on postoperative day 2 (?183±1118 vs. 637±847 ml; P=0.03). Conclusions: although renal complication or serum markers of kidney dysfunction were absent, sensitive indicators revealed significant and similar injury to renal tubules and glomeruli following either OPCAB or ONCAB. These results suggest that avoidance of CPB does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG
Mitral valve surgery for acute papillary muscle rupture following myocardial infarction
No full textBACKGROUND AND AIM OF THE STUDY:
Acute papillary muscle rupture (PMR) is a rare but fatal complication of myocardial infarction (MI). Surgery represents the best treatment option, but carries a high risk. Our experience of emergency mitral valve surgery in patients with acute PMR following MI during the past 22 years is reviewed. METHODS:
Between 1978 and 2000, 33 patients (20 males, 13 females; mean age 64 years; range: 46-80) underwent emergency surgery for acute post-infarct PMR in our institution. The site of MI was anterior in three patients and inferior in 30. Preoperatively, 17 patients had an intra-aortic balloon pump (IABP) inserted, 26 were on inotropic support, and 17 were ventilated. Twenty patients (61%) underwent concomitant coronary bypass grafting (CABG). The valve was replaced in 31 patients and repaired in two. Mean (+/- SD) duration of follow up was 63+/-54 months (range: 0-183 months). RESULTS: Early mortality (in-hospital) was 21% (n = 7). Factors associated with significant risk of early mortality included raised preoperative serum creatinine (p = 0.02), need for preoperative inotropic support (p = 0.03) and preoperative ventilation (p = 0.03). Raised preoperative serum creatinine remained significant on multiple logistic regression (p = 0.04). Postoperatively, 21 patients required an IABP. Mean duration of intensive care unit stay was 4+/-2.5 days (range: 0-10 days). Survival, including in-hospital mortality, at one, five and 10 years was 75+/-7.4, 65+/-8.6 and 32+/-9.7%, respectively. Four patients required valve-related reoperation (three for a paraprosthetic leak, one for failed repair). CONCLUSION: Patients with acute post-infarct PMR present in a severely compromised state. Early mortality is high, but the intermediate outcome is encouraging for operative survivors
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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