1,723,059 research outputs found
Effects of the Selective Protein Kinase C Inhibitor, Ro 31-7549, on the Proliferation of Cultured Mouse Epidermal Keratinocytes
No full textWe have investigated the effects of Ro 31-7549, a selective protein kinase C (PKC) inhibitor, on DNA synthesis and proliferation in two primary mouse epidermal keratinocyte culture systems. In differentiating keratinocytes incubated in medium containing 10% serum and high calcium (approximately 0.5 mM), Ro 31-7549 blocked the inhibitory effect of the phorbol ester 12-0-tetradecanoyl-13-acetate (TPA) (a PKC activator) on keratinocyte DNA synthesis at 24 h [50% maximal response concentration (EC50) = 1 μM], consistent with inhibition of PKC-mediated differentiation. Continuous treatment of the differentiative culture system with the PKC inhibitor resulted in a marked (fourfold) stimulation of [3H]thymidine incorporation at day 7 of exposure, with an EC50 of 0.25 μM. The potencies of these effects of Ro 31-7549 are comparable to that reported for inhibition of TPA-induced platelet 47-kD protein phosphorylation [50% inhibitory concentration (IC50) = 4.4 μM]. The time course of [3H]thymidine incorporation indicated that Ro 31-7549 did not directly stimulate DNA synthesis but instead prevented the loss of proliferative capacity associated with continued culture in this medium. Maximal stimulation (2.6 times) of DNA synthesis was observed on day 4, whereas DNA synthesis at day 1 was unaffected. In a highly proliferative culture system using serum-free medium containing 25 μM calcium, TPA dose-dependently inhibited proliferation with an IC50 of approximately 0.3 nM. This antiproliferative effect of TPA was largely reversed by 0.1 M Ro 31-7549. In the proliferative culture system, 0.75 M Ro 31-7549 also essentially reversed the inhibition of proliferation caused by switching to high (1.0 mM) calcium. These results suggest that the loss of proliferative capacity in differentiating epidermal keratinocyte cultures maybe mediated, at least in part, by PKC
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
Effects of the selective protein kinase C inhibitor Ro 31-7549 on human angiotensin II receptor desensitisation and intracellular calcium release
No full textAbstractThe mechanism underlying type I angiotensin II (Ang II) receptor (AT1 receptor) desensitisation is unknown. Structural features suggest it may be a substrate for protein kinase C (PKC). The effects of a selective PKC inhibitor, Ro 31-7549, on receptor desensitisation were investigated in CHO cells expressing the human AT1 receptor. Desensitisation was demonstrated with respect to the calcium response to Ang II in Fura-2 -loaded cells. Ro 31-7549 had no effect on desensitisation. However, pretreatment with Ro 31-7549 caused a dose-dependent reduction in calcium release from intracellular stores. PKC may therefore act at a locus distal from the receptor itself
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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