1,720,984 research outputs found
The alternative TrkAIII splice variant expressed by human neuroblastomas and glioblastomas targets the centrosome and promotes genetic instability
No full textTrkAIII. A novel hypoxia-regulated alternative TrkA splice variant of potential physiological and pathological importance.
No full text
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
Transcriptional up-regulation of matrix metalloproteinase-9 expression during spontaneous epithelial to neuroblast phenotype conversion by SK-N-SH neuroblastoma cells, involved in enhanced invasivity, depends upon GT-box and nuclear factor kappa B elements
No full textAbstract
Spontaneous epithelial (S) to neuroblast (N) conversion
enhanced the capacity of SK-N-SH neuroblastoma (NB)
cells to invade reconstituted basement membrane in
vitro. This involved a switch to matrix
metalloproteinase (MMP) activity, in particular MMP-9,
and was associated with the induction of MMP-9
expression. N-type-specific MMP-9 expression was
herbimycin A inhibitable tyrosine kinase (possibly csrc)
dependent and was regulated transcriptionally
through GT-box (252), and nuclear factor kB (NFkB;
2600) elements within the MMP-9 gene. GT-box
function was associated with elevated levels of specific
nuclear GT-box binding complexes in N-type cells.
NFkB function was associated with specific p50- and
p65-containing nuclear NFkB binding complex(es). No
function could be attributed to the proximal AP-1 (279)
element, and minimal function was attributed to the
SP-1 (2560), ets (2540), or distal AP-1 (2533) elements.
This was despite elevated levels of specific junD/fra-1
containing proximal AP-1 element binding complex(es)
in N-type cells. Our data highlight a pivotal role for the
GT-box, in concert with the NFkB element, in the
transcriptional up-regulation of MMP-9 expressio
Thioredoxin inhibits microvascular endothelial capillary tubule formation
No full textThioredoxin (Trx) inhibited human HMEC-1 dermal microvascular endothelial cell capillary tubule forming capacity in a Matrigel based
assay in vitro. Inhibition of capillary tubule formation was Trx catalytic site and thioredoxin reductase (TrxR) dependent, mediated at the
Matrigel matrix level, and associated with a shift from morphological differentiation to continuous proliferation, with enhanced cell
spreading resulting in eventual monolayer formation. Soluble complex carbohydrates, which inhibited capillary tubule formation on
Matrigel without induction of cell spreading or monolayer formation, failed to impair Trx promotion of cell spreading and mono-layer
formation, suggesting a shift away from carbohydrate-mediated cell/matrix adhesive interactions. Laminin peptides YIGRS and SIKVAV,
which impaired tubule formation on Matrigel without inducing cell spreading or monolayer formation, partially impaired cell spreading
upon Trx-treated Matrigel without restoring tubule formation, consistent with a potential role for laminin in Trx-mediated effects. Trx
reduced laminin and destabilised laminin/galectin-3 complexes within Matrigel. Native purified EHS Laminin (also containing galectin-3),
but not recombinant galectin-3, restored HMEC-1 capillary tubule formation on Trx-treated Matrigel. These data highlight a novel
deregulatory effect of extracellular Trx upon morphological capillary differentiation that appears to depend upon the reduction of laminin
and destabilisation of its interaction with galectin-3, possibly leading to galectin-3 neutralisation that shifts cell/matrix adhesive interactions
away from being carbohydrate mediated and results in loss of proliferation-inhibiting and differentiation promoting cues from this tumor
basement membrane matrix
Tissue inhibitor of metalloproteinase-2 protection of matrix metalloproteinase-2 from degradation by plasmin is reversed by divalent cation chelator EDTA and the bisphosphonate alendronate
No full textThe degradation of tissue inhibitor of metalloproteinase (TIMP)-free matrix metalloproteinase (MMP)-2 to proteolytically inactive fragments by plasmin was inhibited in equimolar mixtures of purified TIMP-2 and TIMP-free MMP-2 and was not observed in purified MMP-2-TIMP-2 complexes. Divalent cation chelators EDTA and sodium Alendronate did not inhibit plasmin degradation of TIMP-free MMP-2 but reversed the ability of TIMP-2 to protect MMP-2 from degradation by plasmin. Our data confirm a role for plasmin in the clearance of TIMP-free MMP-2, identify a pivotal role for TIMP-2 in regulating MMP-2 longevity in plasmin-containing environments, and highlight a novel therapeutic use for chelators of divalent cations, including the bisphosphonate.Alendronate, in the reversal of TIMP-2 protection of MMP-2 from degradation by plasmin. We propose that these observations are relevant to pathologies that are dependent upon plasmin and MMP-2 activity (e.g., tumor invasion and metastasis)
Inhibition of human MDA-MB-231 breast cancer cells by Matrix Metalloproteinase-3 involves degradation of Plasminogen.
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