1,721,064 research outputs found
Bypass versus angioplasty: Evidence, practice and patient preferences in the light of the new European guidelines on myocardial revascularization,Bypass versus angioplastica: Evidenze, prassi e preferenze del paziente alla luce delle nuove linee guida Europee sulla rivascolarizzazione miocardica
No full textBypass versus angioplasty: Evidence, practice and patient preferences in the light of the new European guidelines on myocardial revascularization,Bypass versus angioplastica: Evidenze, prassi e preferenze del paziente alla luce delle nuove linee guida Europee sulla rivascolarizzazione miocardic
Glucocorticoids in the prevention of restenosis after coronary angioplasty: therapeutic potential
No full textRecurrent multiform Takotsubo cardiomyopathy in a patient with epilepsy: Broken heart or brain?
No full textTakotsubo cardiomyopathy (TC) is known as a reversible left ventricular dysfunction resembling an acute myocardial infarction, without significant coronary obstructions or acute plaque rupture at angiographic investigation. On admission apical and midventricular hypo-/a-/dys-kinesia and compensatory basal hyperkinesia are usually observed; however, the pattern of wall motion abnormalities is very
heterogeneous and a considerable proportion of all cases (around 23% according to the literature) is made up of basal and midventricular hypo-/a-/dys-kinesia with normal kinesia of the apex (“reverse
Takotsubo”) [1]. Epileptic crises are the second most frequent disorder of the central nervous system that trigger TC [2]. We report a “classical” TC associated with a tonico-clonic generalized seizure, followed by two episodes of “reverse” TC, after seven months and five years respectively. In October 2009, a 64 year old woman was admitted to the Emergency Department for typical chest pain after an intense fright, followed by a tonico-clonic generalized seizure. Her medical history included a general convulsive crisis in 2000 and anti-epileptic medications (stopped in 2006). Physical examination revealed blood pressure of 131/70, a heart rate of 104 beats/min with extrasystolia, oxygen saturation of 97%, no heart murmurs and no pulmonary edema. An electrocardiogram An electrocardiogram showed sinus tachycardia with ectopic premature ventricular beats and QS complex in leads V1 and V2 [Fig. 1 A]. A transthoracic echocardiogram showed an extensive area of apical akinesia of the left ventricle and a severely reduced systolic function. The CK-MB and TnT peaks were 16.2μg/L and 0.54ng/mL respectively. A coronary angiography and a ventriculography revealed coronary arteries free from injury and a left ventricular ejection fraction of 42%. The ninth-day echocardiogram showed a septum-limited hypokinesia and a LVEF of 57%, confirming the diagnosis of TC. In May 2010 the patient came back to our Department due to a further episode of chest oppression which had started at rest the day before. Her vital parameters were stable and the ECG did not show any important signs except for the presence of septal Q waves [Fig. 1 B]. CK-MB and TnT peaks were 6.5μg/L and 0.18ng/mL respectively. A trans-thoracic echocardiogram showed a mildly dilated left ventricle with a large area of hypokinesia in the medium-basal segments and severe mitral functional regurgitation, with central jet [Fig. 2 A–B]; the LVEF was significantly reduced (35%). Owing to the recent report of healthy coronary arteries, a cardio-CT was performed on the seventh day; it confirmed the patency of the coronary tree (Agatston score: 0) and showed a decrease in the medium-basal hypokinesia with recovery of the ejection fraction. An eleventh-day echocardiogram showed recovery of LVEF (52%) and a mild mitral regurgitation, consistent with a diagnosis of “reverse Takotsubo”. In July 2014 the patient was evaluated for a short-term memory disturbance and the concomitant onset of mild oppressive precordial pain. At the Emergency Department an echocardiogram showed akinesia of the interventricular septum and hypokinesia of medium and basal portions of the anterior and inferior wall of the left ventricle, with an ejection fraction of 44% and a medium grade mitral regurgitation (no significant alterations at ECG [Fig. 1 C]; TnT peak: 175ng/L). The neurological presentation was interpreted as a post-critical amnesia following a partial epileptic seizure. Six days after the onset, the LVEF recovered and the mitral regurgitation became mild, confirming the diagnosis of a further “reverse TC”.
According to a recent review [3], our patient belongs to that 5% of the population presenting TC relapse within six years; a previous study [4] reported a higher rate (11.4%) over the first 4years.
This case shows that Takotsubo cardiomyopathy is a multiform, dynamic clinical entity that may occur with but also without an evident trigger and with different myocardial involvement even in the same individual. The triple recurrence not only suggests a predisposition but also leads to some pathogenetic considerations. Several studies have shown that the sympathetic innervation becomes progressively more sparse from base to apex of the heart, while an opposite beta-receptor concentration gradient exists, so that the apical myocardium seems to be more responsive than the basal to adrenergic stimuli [5]. The resulting cardiotoxic effect may explain the classical apical ballooning [6]; it has been proposed that the “reverse TC” pattern may result from differences between individuals in beta-receptor density gradient as well as in regional adrenergic sensitivity [7]. What we suggest is that the pathophysiology of TC cannot be based on mere anatomic and subcellular pre-existing conditions: the type and the intensity of stimuli could play a substantial and possibly crucial role in the way the myocardium is damaged. Furthermore, the first TC was associated with a generalized seizure, in line with the majority of cases reporting a relation between TC and epilepsy [2] while the second crisis was partial and seizures less frequently trigger a reverse type of TC, thus increasing the complexity of the case.
To explain the heterogeneous echocardiographic pattern in consecutive relapses, the hypothesis that previously affected myocardium is protected via a phenomenon analogous to regional ischemic preconditioning has been proposed [8]; however, this is not applicable to our patient, since the first TC was “classical” and the following two were both “reverse”.
This case also highlights the role of catecholamines in the genesis of both TC and epileptic seizure: since in the first episode the patient reported that the chest pain arose before the convulsive crisis, the same intense emotional stress may have triggered each of them simultaneously, suggesting the importance of adrenergic sprouting in the pathogenesis of both conditions. It is also possible that the catecholamines released during the seizure led to the worsening of LVEF.
To the best of our knowledge, this is the third case reported in the literature of a relapsing association between TC and epileptic crises in the same patient [9,10]; however, there are more than sixty cases of a single presentation of this relationship [2], suggesting that these patients need close cardiologic follow-up
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
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
- …
