1,721,049 research outputs found
Evidence for avb3 and avb5 integrin-like vitronectin (VN) receptors in Candida albicans and their involvement in Yeast cell adhesion to VN.
No full textThe expression of integrin vitronectin (VN) receptors on Candida albicans yeasts and their involvement in the adhesion to VN were investigated. By; immunofluorescence and cytofluorimetric analysis, several antibodies directed against human alpha v, beta 3, beta 5, alpha v beta 3, or alpha v beta 5 integrin positively stained C. albicans yeasts. Biochemical analysis on yeast lysates with anti-human alpha v, beta 3, or beta 5 antibody revealed molecular species of 130, 110, 100, and 84 kDa. The 130-kDa band was identified as Mr,whereas the doublet of 110/100 kDa and the 84-kDa band likely correspond to the beta 3 and beta 5 subunits, respectively. Some 48%-54% of Candida yeasts specifically adhered to VN, and this binding was strongly inhibited by anti-human alpha v, beta 3, alpha v beta 3, and alpha v beta 5 antibodies and by RGD- but not RGE-containing peptides. In addition, VN inhibited C. albicans adherence to a human endothelial cell Une. Thus, C. albicans in the yeast phase expresses VN receptors antigenically related to the vertebrate alpha v beta 3 and alpha v beta 5 integrins, which mediate its adhesion to VN
CD16 engagement induces ubiquitination and degradation of Syk and ZAP-70 tyrosine kinases in human NK cells
No full textTriggers Deriving From CD44 Crosslinking Intervene In the Activation of Lytic Functions of Human Natural Killer Cells
No full textMeccanismi implicati nello spegnimento delle vie di segnalazione mediate dal recettore ad alta affinità per le IgE (FcepsilonRI)
No full textTyrosine kinase-dependent activation of human NK cell functions upon triggering through CD44 receptor
No full textWe recently showed evidence of CD44-mediated enhancement of natural killer (NK) cell cytotoxic activity and induction of intracellular Ca2+ flux. In this study, we evaluated whether CD44 plays a stimulatory role in NK cell functions, such as cytokine production and activation antigen expression. Our results indicate that ligation of the CD44 receptor results in the induction of expression of the CD69 surface activation antigen as well as in the enhancement of phorbol ester-induced TNF-alpha secretion. We report also evidence for the coupling of CD44 receptor to a protein tyrosine kinase(s) pathway. CD44 engagement rapidly stimulates the tyrosine phosphorylation of several cellular substrates. Pretreatment of NK cells with the tyrosine kinase inhibitor herbimycin A resulted in marked decrease of CD44-stimulated phosphorylation, indicating that it activates tyrosine kinase(s). Furthermore, the drug also prevents CD44-mediated TNF-alpha production and CD69 expression. These findings indicate that protein tyrosine phosphorylation is an early and critical event in CD44-mediated activation of NK cell functions
Role for the Rac1 exchange factor Vav in the signaling pathways leading to NK cell cytotoxicity
No full textHere we investigate the activation of and a possible role for the hematopoietic Rad exchange factor, Vav, in the signaling mechanisms leading to NK cell-mediated cytotoxicity, Our data show that direct contact of NK cells with a panel of sensitive tumor targets leads to a rapid and transient tyrosine phosphorylation of Vav and to its association with tyrosine-phosphorylated Syk, Vav tyrosine phosphorylation is also observed following the activation of NK cells through the low-affinity Fc receptor for IgG (Fc gamma RIII), In addition, we demonstrate that both direct and Ab-mediated NK cell binding to target cells result in the activation of nucleotide exchange on endogenous Rac1. Furthermore, Vav antisense oligodeoxynucleotide treatment leads to an impairment of NK cytotoxicity, with Fc gamma RIII-mediated killing bring more sensitive to the abrogation of Vav expression. These results provide new insight into the signaling pathways leading to cytotoxic effector function and define a role for Vav in the activation of NK cell-mediated killing
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
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