1,720,968 research outputs found
Carbenoxolone inhibits volume-regulated anion conductance in cultured rat cortical astroglia.
No full textExclusive perivascular localization of AQP4ex in mouse brain after stereotaxic lentiviral gene delivery
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Aquaporin-4 Orthogonal Arrays of Particles from a physiological and pathophysiological point of view
No full textEndfoot targeting of AQP4ex is the determining factor of the anchoring of AQP4 water channel molecules at the brain-blood interface
No full textAQP4 plays a central role in the preservation of the CNS water homeostasis, essential for the maintenance of osmotic composition and volume within the glial and neuronal compartments. The recent discovery of the extended isoform of AQP4 (AQP4ex), generated by translational readthrough, revealed a potential new mechanism of water transport regulation and polarization at the brain-blood interface.
We employed CRISPR/Cas9 technology to generate an AQP4ex-KO mouse model and evaluate the effect on the overall AQP4 expression, polarization, supramolecular organization in orthogonal arrays of particles (OAPs) and neuromyelitis optica (NMO-IgG) autoantibodies binding.
In WT mouse, AQP4ex, representing about 10% of all AQP4 isoforms, showed a polarized distribution in the cerebrum mostly confined to the pericapillary astrocyte endfeet.
AQP4ex removal completely suppressed the specific location of AQP4 at the astrocyte endfeet and was compensated by an increased expression of the canonical isoforms (M1 and M23) indicating that the KI stop codons tightly work. Without AQP4ex, AQP4 was mislocalized in the brain parenchima, and α-syntrophin expression, the selective partner for AQP4 localization, was partially altered. The supramolecular organization of AQP4 in OAPs was subtly altered. Indeed, the absence of AQP4ex slightly reduced the size of AQP4-OAPs but the number of AQP4-OAPs pools remained largely the same. The absence of AQP4 at the perivascular pole completely abolished the binding of pathogenic human neuromyelitis optica autoantibodies to the brain. This study provides the first direct evidence in vivo on the specific role of AQP4ex in AQP4 perivascular OAP assembly and confinement, as well as its involvement as a structural component of the glial endfoot membrane protein functional unit
A novel human aquaporin-4 splice variant exhibits a dominant-negative activity: a new mechanism to regulate water permeability.
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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
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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