1,721,043 research outputs found
In vitro and in vivo effects of desmopressin on platelet function
No full textBACKGROUND AND OBJECTIVE: Desmopressin (DDAVP) may shorten bleeding time in patients with disorders of platelet function, but its mechanism of action in these conditions is still a matter of debate. In particular, contrasting results have been obtained concerning the ability of DDAVP to interact with platelets and to activate them directly. To gain further information on the DDAVP-platelet interaction, we studied the in vitro and ex vivo effects of DDAVP on platelet function.
DESIGN AND METHODS: Platelet responses to DDAVP both as a single agent and in conjunction with agonists of platelet activation were investigated. For in vitro experiments platelets were obtained from healthy adult volunteers, while the ex vivo effects of DDAVP were studied in 12 patients with a bleeding disorder receiving a test dose of this drug.
RESULTS: DDAVP in vitro did not induce either platelet aggregation or surface expression of the activation-dependent antigens; it did, however, greatly inhibit platelet aggregation response to vasopressin (AVP) and increased the maximal extent of platelet aggregation induced by collagen and ADP. DDAVP infusion did not promote the expression of activation antigens, but significantly enhanced ex vivo platelet aggregation stimulated by ADP and collagen. This priming effect was observed in patients with von Willebrand's disease, hemophilia A, May-Hegglin anomaly, gray platelet syndrome and Ehlers-Danlos syndrome. In all these patients bleeding time was shortened by DDAVP infusion. In contrast, neither platelet aggregation nor bleeding time was modified in two subjects with Glanzmann's thrombasthenia.
INTERPRETATION AND CONCLUSIONS: Our in vitro experiments indicate that DDAVP interacts directly with platelets and facilitates their activation via other agonists. In vivo results suggest that this effect occurs and is clinically relevant in patients with platelet dysfunction responding to DDAVP with a shortening of bleeding time
Influenza del polimorfismo C677T del gene della MTHFR sui livelli di omocisteina plasmatici e sul rischio trombotico
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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
Impaired expression of dipeptidylaminopeptidase IV (DAPN)/CD26 in lymphocytes of hemophiliacs
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High prevalence of fibrin formation defects in women with menorrhagia and congenital bleeding disorders
No full textFactor V Leiden mutation and risk of thrombotic complications in children treated for lynphoprolipherative diseases
No full textScreening dei difetti dell'emostasi con Platelet Function Analyzer (PFA-100) in donne con meno-metrorragia
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