1,720,974 research outputs found
Adenoviral GI-protein overexpression: Impact on beta-adrenergic signaling in cardiac myocytes and intact trabeculae
No full textInfluence of pyruvate on economy of contraction in isolated rabbit myocardium
No full textBackground: Treatment of acute heart failure frequently requires positive-inotropic stimulation. However, there is still no inotropic agent available, which combines a favourable haemodynamic profile with low expenditure for energy metabolism. Pyruvate exhibits positive inotropic effects in vitro and in patients with heart failure. The effect on myocardial energy metabolism however remains unclear, but is meaningful in light of a clinical application. Aims and methods: We investigated the influence of pyruvate on contractility and oxygen consumption in isolated isometric contracting rabbit myocardium compared to P-adrenergic stimulation with isoproterenol. Results: Pyruvate (30 mM) increased developed force from 18.7 +/- 4.1 to50.8 +/- 12.1 mN/mm(2) (n= 10,p < 0.01). Force-time integral (FTI) increased by 329%, oxygen consumption assessed by diffusion-microclectrode technique increased from 2.86 +/- 0.30 mlO(2)/min 100 g to 6.28 +/- 1.28 mlO(2)/ min 100g(n=7,p < 0.05). Economy of myocardial contraction calculated as the ratio of total FTI to oxygen consumption remained unchanged. In contrast, while isoproterenol (10 mu M) produced a comparable increase in developed force from 21.4 +/- 8.3 to 67.3 +/- 15 mN/mm(2) (n=7,p < 0.01),FTI increased only by 260% and MVO2 increased from 2.96 +/- 0.43 to 6.12 +/- 1.01 mlO(2)/min 100 g (n=7,p < 0.01); thus, economy decreased by 23% (n=7,p < 0.05). Conclusion: Pyruvate does not impair economy of myocardial contraction while isoproterenol decreases economy. Regarding energy expenditure, pyruvate appears superior to isoproterenol for the purpose of positive inotropic stimulation. (c) 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved
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
Improved systolic and diastolic myocardial function with intracoronary pyruvate in patients with congestive heart failure
No full textBackground: Pyruvate increases myocardial performance in isolated myocardium and improves hemodynamics in patients with congestive heart failure. Aims: To investigate the influence of pyruvate on detailed parameters of systolic and diastolic left ventricular (LV) function. Methods and Results: In patients with heart failure due to dilated cardiomyopathy (LVEF 30 +/- 4%, n = 9) pyruvate was infused intracoronarily. LV function was analysed before, during and after application of different pyruvate concentrations using a LV-micromanometer catheter. LV volumes were determined using cine ventriculography. Pyruvate increased maximum rate of LV isovolumic pressure rise (Peak + dP/dt) from 802 +/- 106 to 1125 +/- 103 mmHg/s (P < 0.05). Left ventricular end-diastolic pressure declined in parallel from 17 +/- 2 to 12 +/- 2 mmHg (P < 0.05) and heart rate decreased from 79 +/- 4 to 72 +/- 5 min(-1) (P < 0.05). Stroke volume index increased from 34 +/- 4 to 43 +/- 6 ml/m(2) (P < 0.05), end-diastolic LV volume remained unchanged. thus left ventricular ejection fraction increased with pyruvate from 30 +/- 4 to 39 +/- 4% (P < 0.05). Maximum rate of LV isovolumic pressure decline (Peak - dP/dt) was significantly increased with pyruvate (from 794 +/- 94 to 980 +/- 108 mmHg/s; P < 0.05) and mean arterial pressure increased from 80 +/- 5 to 88 +/- 4 mmHg (P < 0.05). Discontinuation of pyruvate resulted in immediate reversibility of its effects. Conclusion: Intracoronary pyruvate improves systolic and diastolic myocardial function and increases ejection fraction without increasing heart rate. Pyruvate thus exhibits the profile of a favourable inotropic agent, however, further investigation for the treatment of patients with acute heart failure is mandatory. (C) 2003 European Society of Cardiology. Published by Elsevier B.V. All rights reserved
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
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