1,720,972 research outputs found
Cyclic GMP modulates store-operated calcium entry inducing phosphatidylserine translocation at the surface of megakaryocytic cells.
Get PDFWhen subjected to stimulation, cells from the vascular compartment show a spontaneous collapse of the plasma membrane phospholipid
asymmetry and phosphatidylserine is exposed at the external leaflet. Thus, phosphatidylserine externalization is essential for normal hemostasis
and phagocytosis. The mechanism governing the migration of phosphatidylserine to the exoplasmic leaflet is not yet fully understood. We have
proposed that store-operated calcium entry (SOCE) constitutes a key step of this process. Here, interaction of [Ca2+]i, cAMP and cGMP pathways
and phosphatidylserine exposure was examined in human megakaryocytic cells. The membrane permeable cAMP and cGMP analogues, pCPTcAMP
and pCPT-cGMP, enhanced the Ca2+ signal induced by ionophore and SOCE. Responses to pCPT-cAMP and pCPT-cGMP were independent
of protein kinase A, protein kinase G (PKG) or ERK pathways. Inhibition of small G-proteins reduced or abolished the increase of [Ca2+
]i induced by pCPT-cAMP or pCPT-cGMP, respectively. pCPT-cGMP but not pCPT-cAMP enhanced the ability of cells to expose phosphatidylserine.
This effect was not prevented by the inhibition of PKG or small G-proteins. These results show the differential role of cyclic nucleotides
in the Ca2+-dependent membrane remodeling. Hence, pCPT-cGMP is another regulatory element for the completion of SOCE-induced
phosphatidylserine transmembrane redistribution in HEL cells through a mechanism implicating small G-protein
Membrane Microvesicles as Actors in the Establishment of a Favorable Prostatic Tumoral Niche: A Role for Activated Fibroblasts and CX3CL1-CX3CR1 Axis
No full text
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
Microvesicle-mediated release of soluble LH/hCG receptor (LHCGR) from transfected cells and placenta explants
Get PDFPlacental hCG and pitutary LH transduce signals in target tissues through a common receptor (LHCGR). We
demonstrate that recombinant LHCGR proteins which include the hormone-binding domain are secreted from
transfected cells and that natural LHCGR is also secreted from human placental explants. LHCGR recombinant
proteins representing varying lengths of the N-terminal extracellular domain were expressed in Chinese Hamster
Ovary cells in suspension culture. Secretion was minimal up to 72h but by 96h 24-37% of the LHCGR had been
released into the culture medium. The secreted proteins were folded and sensitive to glycosidases suggesting
N-linked glycosylation. Secretion was independent of recombinant size and was mediated via structurally defined
membrane vesicles (50-150nm). Similarly cultured human early pregnancy placental explants also released LHCGR
via microvesicles. These studies provide the first experimental evidence of the possible mechanistic basis of the
secretion of LHCGR
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
- …
