1,720,963 research outputs found
Evaluation of hyperbranched Poly-L-Lysine uptake and toxicity on inner ear derived cell line as a function of concentration and architecture
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Protective effects of minocycline and MDL 28170 in gentamicin ototoxicity
No full textGentamicin side-effects on cochlear structures and function are well known, but not the detailed intracellular molecular mechanisms which lead to aminoglycoside induced ototoxicity. Hair cell death occurs by apoptosis, by the activation of enzymatic cascades known to be involved in the programmed cell death, or by the release of cytochrome-c from the damaged mitochondria. In this paper we have investigated the active role of minocycline, a second-generation tetracycline, and of MDL 28170, a selective calpain inhibitor, in the protection of hair cells from GM damage in in vitro organospecific cultures of the organ of Corti. We used cultures from neonatal (P3) rat cochlea, treated with different dosages of GM, alone, or with the two protector drugs. We have observed a dose-dependent OHC and IHC loss. The GM damage was reduced after treatment with both drugs. These results were also supported by the Disk Diffusion Susceptibility Test (Kirby-Bauer Method), in which we used drug treated organs of Corti. The data suggest that minocycline, previously reported to inhibit the release of cytochrome-c, and MDL 28170, prevent GM induced programmed cell death pathway in cochlear HC
Evaluation of cell viability and cell toxicity in PC12 and OCk-3 as a function of polycation concentration and architecture
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Cisplatin-induced apoptosis in human promyelocytic leukemia cells.
No full textCis-diamminedichloroplatinum (II) cisplatin (CDDP) is an
organometallic compound frequently used in anti-cancer therapy, in
particular ovarian, testicular, and head and neck tumors. We found
cisplatin was effective against human promyelocytic leukemia cell
line HL-60, inhibiting cell cycle progression and inducing time- and
concentration- dependent cell death. Presence of nuclear
fragmentation, caspase-3 cleavage and annexin V positivity suggests
cell death occurred by apoptosis, although DNA internucleosomal
fragmentation was not detected. In addition, analysis of
malondialdehyde (MDA) production and protein carbonylation indicated
that cisplatin increased lipid peroxidation and oxidation of cell
proteins. This occurrence was prevented by antioxidants such as
N-acetylcysteine (N-aC) and glutathione (GSH), which, consistently,
were also able to prevent CDDP-induced cell death. Collectively,
these findings indicate that, besides growth inhibition, an increase
of oxygen radicals and lipid degradation can account for a
significant part of CDDP-induced apoptosis
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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