1,720,956 research outputs found
Endothelium-dependent relaxation by acetylcholine is impaired in hypertriglyceridemic humans with normal levels of plasma LDL cholesterol
No full textAbstractOBJECTIVESPatients with high triglyceride (of which very low density lipoproteins [VLDL] are the main carriers), but with normal low density lipoprotein (LDL) cholesterol levels, were examined for in vivo endothelium function status.BACKGROUNDVery low density lipoproteins inhibit endothelium-dependent, but not -independent, vasorelaxation in vitro.METHODSThree groups were studied: 1) healthy volunteers (n = 10; triglyceride 1.24 ± 0.14 mmol/liter, LDL cholesterol 2.99 ± 0.24 mmol/liter); 2) hypertriglyceridemic (n = 11; triglyceride 6.97 ± 1.19 mmol/liter,∗ LDL cholesterol 2.17 ± 0.2 mmol/liter, ∗p < 0.05); and 3) hypercholesterolemic (n = 10; triglyceride 2.25 ± 0.29 mmol/liter,∗ LDL cholesterol 5.61 ± 0.54 mmol/liter∗; ∗p < 0.05) patients. Vasoactive responses to acetylcholine, sodium nitroprusside, noradrenaline, NG-monomethyl-l-arginine and postischemic hyperemia were determined using forearm venous occlusion plethysmography.RESULTSResponses to acetylcholine (37 μg/min) were significantly dampened both in hypercholesterolemic (% increase in forearm blood flow: 268.2 ± 62) and hypertriglyceridemic patients (232.6 ± 45.2) when compared with controls (547.8 ± 108.9; ANOVA p < 0.05). Responses to sodium nitroprusside (at 1.6 μg/min: controls vs. hypercholesterolemics vs. hypertriglyceridemic: 168.7 ± 25.1 vs. 140.6 ± 38.9 vs. 178.5 ± 54.5% increase), noradrenaline, NG-monomethyl-l-arginine and postischemic hyperemic responses were not different among the groups examined.CONCLUSIONSAcetylcholine responses are impaired in patients with pathophysiologic levels of plasma triglycerides but normal plasma levels of LDL cholesterol. The impairment observed was comparable to that obtained in hypercholesterolemic patients. We conclude that impaired responses to acetylcholine normally associated with hypercholesterolemia also occur in hypertriglyceridemia. These findings identify a potential mechanism by which high plasma triglyceride levels may be atherogenic independent of LDL cholesterol levels
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
Dietary supplementation with l-arginine fails to restore endothelial function in forearm resistance arteries of patients with severe heart failure
No full textObjectives.We sought to examine the efficacy of dietary supplementation of l-arginine on endothelium-dependent vasodilation in patients with congestive heart failure.Background.Endothelial dysfunction, as evidenced by a diminished response to such vasodilators as acetylcholine, is well defined in patients with heart failure. These responses are improved by intraarterial infusion with l-arginine. Because l-arginine is a semiessential amino acid, we investigated the effects of dietary l-arginine on endothelium-dependent vasodilation in these patients.Methods.Twenty patients with heart failure (New York Heart Association functional class III/IV, mean [±SE] age 51.3 ± 1.7 years) and seven healthy control subjects (mean age 52.6 ± 3.3 years) were studied. All patients continued taking their usual treatment. Responses to acetylcholine and sodium nitroprusside were determined using forearm plethysmography. Patients with heart failure received either l-arginine (20 g/day every day for 28 days) or placebo (vehicle syrup in equal amounts) in a double-blind protocol. The calculated power of the study was between 62% and 80% to detect a 30% to 40% change in area under the dose-response (forearm vascular resistance) curve.Results.Responses to acetylcholine, but not to sodium nitroprusside, were significantly attenuated in patients with heart failure compared with control subjects (mean area under curve [Auc], control subjects vs. patients with heart failure: 1,125.4 ± 164.5 vs. 617.3 ± 116.6 U, p < 0.05, by Student t test). A significant increase in urea and aspartate transaminase levels in patients receiving active l-arginine treatment was observed. Responses to acetylcholine (AUC; before vs. after l-arginine: 641.5 ± 126.7 vs. 695.9 ± 151.9 U) and sodium nitroprusside were not affected by either l-arginine or placebo.Conclusions.Endothelial dysfunction was apparent in patients with heart failure despite rigorous vasoactive treatment. Oral administration with l-arginine was ineffective in influencing endothelial function in these patients
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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