1,720,964 research outputs found
The endothelial plasma membrane transporter bilitranslocase mediates rat aortic vasodilation induced by anthocyanins.
No full textBACKGROUND AND AIMS:
Anthocyanins, a sub-class of flavonoids, induce endothelium-dependent vasorelaxation, by activating endothelial nitric oxide synthase and consequently increasing production of the vasorelaxant agent nitric oxide. It is not yet clear if anthocyanin-induced vasorelaxation starts with their interaction with plasma membrane receptors in the extracellular compartment, or with their membrane transport toward intracellular molecular targets. We therefore investigated the possible role of bilitranslocase (TC 2.A.65.1.1), an endothelial plasma membrane carrier that transports flavonoids, in the vasodilation activity induced by anthocyanins.
METHODS AND RESULTS:
Vascular reactivity was assessed in thoracic aortic rings obtained from male Wistar rats. Pre-treatment of aortic rings with anti-sequence bilitranslocase antibodies targeting the carrier, decreased vasodilation induced by cyanidin 3-glucoside and bilberry anthocyanins.
CONCLUSION:
Here we show for the first time that bilitranslocase mediates a critical step in vasodilation induced by anthocyanins. This offers new insights into the molecular mechanism involved in endothelium-dependent vasorelaxation by flavonoids, and the importance of their specific membrane carriers
Anti-ischemic activity of anthocyanins in the isolated rat heart is bilitranslocase-mediated
No full text
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
Presence of bilitranslocase in the vascular system and its role in the vasodilatation activity of anthocyanins
No full textBackground: Flavonoids are well known for their vasodilata- tion activity. Their mechanism of action is still to be elucidated. Bilitranslocase is a bilirubin-specific membrane carrier that is also responsible for the ATP-independent transport of flavonoids across the cell membrane [1]. Recently, the expression of bilitranslocase in the endothelium has been characterized [2]. The aim of the study was to examine the possible role of bilitranslocase in the vasodilatation activity of flavonoids. As a source of flavonoids we used bilberries, which are abundant in anthocyanins that show strong affinity for bilitranslocase. Methods: A bilberry extract, of which the anthocyanin content was quantified by HPLC-DAD analysis, was used. Anthocyanins were expressed as a standard of cyanidin 3-glucoside (mg/L). Thoracic aortic rings obtained from male Wistar rats were mounted in standard organ baths filled with Krebs-Henseleit solution, maintained at 37°C with a 95% O2 / 5% CO2 mixture. Rings were divided into four groups: control group (intact aortic rings), endothelium denuded rings, rings with nitric oxide synthase (NOS) activity inhibited by application of L-NNA (0.1 mmol/L) and rings with inhibited bilitranslocase-mediated membrane transport. In the last group, aortic rings were pre-incubated for 30 min with mono-specific polyclonal bilitranslocase antibodies (0.24 mg/mL). After inducing submaximal contraction (60 mmol/L KCl) in all studied groups, a chemically characterized bilberry extract was applied in increasing concentrations (0.5-20 mg/L). Vascular tone was measured isometrically by a mechano-electrical transducer. Further tests were done to check the expression of bilitranslocase in the vascular system (endothelial cell line EA.hy 926 and vascular smooth muscle cell line A7r5) by Western blot analysis using bilitranslocase antibodies.
Results: Western blot analysis showed the presence of bilitranslocase on both endothelial and smooth muscle cells. Bilberry extract relaxed aortic rings in a concentration- dependent manner in the control group, but neither in endothelium-denuded aortic rings nor in rings with inhibited NOS. The maximum relaxation (19.00 ± 2.01%, n = 5) observed at 20 mg/L in the group with inhibited bilitranslocase activity was significantly lower (p < 0.001) compared to the control group (34.95 ± 3.11%, n = 10).
Conclusion: Our results show that the vasodilatation activity of anthocyanins in bilberry extract is partly dependent on the bilitranslocase-mediated transport of flavonoids into the endothe- lium, followed by the activation of NOS. However, even though the bilitranslocase is also expressed on smooth muscle cells, its role in the vasodilatation activity on these cells remains negligible. References
1. Passamonti S, Terdoslavich M, Franca R, Vanzo A, Tramer F, Braidot E, Petrussa E and Vianello A: Bioavailability of flavonoids: a review of their membrane transport and the function of bilitranslocase in animal and plant organisms. Curr Drug Metab 2009, 10:369–394.
2. Maestro A, Terdoslavich M, Vanzo A, Kuku A, Tramer F, Nicolin V, Micali F, Decorti G and Passamonti S: Expression of bilitranslocase in the vascular endothelium and its function as a flavonoid transporter. Cardiovasc Res 2009 in press
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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