1,720,971 research outputs found
Efficacy of transdermal clonidine in short-term treatment of cluster headache: a pilot study.
No full textSome clinical as well as pharmacological indications seem to suggest that a reduction of the noradrenergic tone occurs in cluster headache (CH), during both the active and remission periods. But sharp fluctuations of the sympathetic system may trigger the attacks. Clonidine, an alpha-2-adrenergic presynaptic agonist, regulates the sympathetic tone in the central nervous system. Therefore, a continuous administration of low-dose clonidine could be potentially beneficial in the active phase of CH by antagonizing the variations in noradrenergic tone. After a run-in week, we administered transdermal clonidine (5 - 7.5 mg) for one week to 13 patients suffering from CH, either episodic (8 cases) or chronic (5 cases). During clonidine treatment, the mean weekly frequency of attacks dropped from 17.7 +/- 7.0 to 8.7 +/- 6.6 (p = 0.0005), the pain intensity of attacks measured on the visual analogue scale from 98.0 +/- 7.2 to 41.1 +/- 36.1 mm (p = 0.001), and the duration from 59.3 +/- 21.9 to 34.3 +/- 24.6 min (p = 0.02). This open pilot study strongly suggests that transdermal clonidine may be an effective drug in the preventive treatment of CH. Its efficacy is possibly due to its central sympatho-inhibition, which reduces or prevents the occurrence of fluctuations of noradrenaline release that may induce the attacks
Platelet serotonin pathway in menstrual migraine
No full textIn order to understand the possible 5-hydroxytryptamine (5HT) anomalies in migraine, particularly in the period before the headache attack, we compared the levels of 5HT, its stable metabolite 5-hydroxyindoleacetic acid (5HIAA) and platelet monoaminoxidase (MAO) activity in patients with menstrual migraine with those of healthy female controls. In every subject, blood samples were drawn during both follicular and late luteal phases of the menstrual cycle. In controls, platelet 5HT levels remained stable, whereas 5HIAA levels and MAO activity were higher in the luteal than in the follicular phase, suggesting an increased catabolism of 5HT which occurs physiologically just before menses. In menstrual migraine 5HIAA levels and MAO activity showed similar changes with higher values in the luteal than in the follicular phase. The luteal phase values were significantly higher than those of controls. Also, and in contrast to controls, 5HT levels decreased in the luteal phase. These data suggest that 5HT availability is reduced in menstrual migraine, possibly due to an increased catabolism and/or to a reduced synthesis, and hence predisposes patients to migraine attacks
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
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