1,720,965 research outputs found
High production of endothelin after foam sclerotherapy: a new pathogenetic hypothesis for neurological and visual disturbances after sclerotherapy
No full textBACKGROUND: Visual and neurological disturbances have always been reported following liquid sclerotherapy (LS) for venous insufficiency. In 1993 Cabrera introduced foam sclerotherapy (FS) using a detergent sclerosant as Lauromacrogol 400 or sodium tetradecyl sulphate. Several authors have reported with FS an increased incidence of such transient visual disturbances and neurological complications. This has been associated with gas or air used to generate the sclerosing foam. The frequent association of the presence of a patent foramen ovale, a common condition in normal population, and such complications has led several authors to consider neurological and visual disturbances as paradoxical gas embolism.
OBJECTIVE: We are introducing a new pathogenetic hypothesis for sclerotherapy complications. Medical literature shows evidence of a clear relationship among cerebral and retinal vasospasm, migraine and intimal irritation. We think that the irritating sclerosant agent may stimulate a significant release of vasoactive substances from the venous wall, specifically endothelin 1 (ET-1), the most powerful vasoconstricting agent.
METHOD: We have studied systemic ET-1 levels after LS and FS with Lauromacrogol 400 in a group of 13 rats at one and five minutes after injection.
RESULTS: While ET-1 levels did not change significantly in control and in the LS group, a significant increase was detected after FS at one and five minutes.
CONCLUSION: We conclude that should the same results be found in patients treated using sclerosing foam (SF), ET-1 levels may closely correlate to the onset of visual or cerebral complications. Due to the bronchoconstrictor activity of ET-1, a relationship with post-treatment cough can be also postulated
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
Significant endothelin release in patients treated with foam sclerotherapy
No full textBackground: Foam sclerotherapy has been proven to be a safe and effective treatment for superficial venous insufficiency, but transient visual and neurological disturbances continue to be reported. These side effects have been postulated to be related to the presence of air or gases in the sclerosing foam. We present a differing hypothesis where significant
Endothelin release from the treated varices is capable of generating such complications.
Material and methods: we have tested the release of Endothelin 1 in 12 rats where a sclerotherapy was performed with liquid or foamed sodium tetradecylsulphate. Moreover
we have measured Endothelin 1 in the systemic circulation and in a draining vein from
the treated area in a group of 11 patients treated with foam sclerotherapy with
Lauromacrogol 400
Results: Rats treated with STS showed significant increase in ET 1 levels at 1 and five minutes after foam sclerotherapy. Patients treated with foam sclerotherapy showed
significant increase in ET 1 levels and this significantly correlated with local ET 1 levels.
Conclusions: Evidence of Endothelin 1 release after sclerotherapy represents a plausible relationship explaining neurological and visual disturbances
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
Signifikante Endothelin-Freisetzung bei Patienten, die mit Sklerotherapie behandelt wurden
No full textIn einer neuen Studie demonstrierten wir, dass Polidocanolschaum in der Lage ist, in einem Tiermodell Endothelin-1 (ET-1) signifikant zu erhöhen. Beim ersten Teil der Studie testeten wir die ET-1-Freisetzung bei Ratten nach der Injektion von Natriumtetradecylsufat (STS) 1 % als Flüssigkeit und Schaum. Im zweiten Teil präsentierten wir den ersten klinischen Bericht von einer ET-1-Freisetzung nach Schaumsklerotherapie bei Patienten mit chronischer venöser Insuffizienz (CVI)
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
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