1,720,961 research outputs found
Roles of c-Src and hDRR1 in glioma cell invasion
No full textMalignant glioma is the major brain tumor in adults, and has a poor prognosis. The failure to control invasive cell subpopulations may be the key reason for local glioma recurrence after radical tumor resection, and may contribute substantially to the failure of the other treatment modalities, such as radiation therapy and chemotherapy. As a model for this invasion, we have implanted spheroids from a human glioma cell line (U251) in three-dimensional collagen type I matrices which these cells readily invade. First, we observed that the Src family kinase specific pharmacological inhibitors PP2 and SU6656 significantly inhibited the invasion of the cells in this assay, which was then confirmed by expression of two inhibitors of Src family function, dominant inhibitory Src and CSK. Fluorescent time-lapse microscopy on U251 cells stably expressing a YFP-actin construct shows that PP2 caused the disappearance of peripheral membrane ruffles within minutes in monolayer cultures, and induced the loss of actin bursting at the leading tip of the invadopodium in three-dimensions. The inhibition of Src family activity is thus a potential therapeutic approach to treating highly invasive malignant glioma. In the second part, we analyze the role of a novel protein, hDRR1, which was cloned from a functional screen of genes involved in glioma cell hyperinvasion. We show that hDRR1 localizes endogenously and when overexpressed to the actin cytoskeleton, via two independent but homologous actin-localization domains. We also show that the C-terminus of hDRR1 can bind to the light chain of MAP1A and MAP1B, and that hDRR1 overexpression in invading glioma cells results in a decrease in the percentage of cells adopting a polarized morphology. These results suggest that hDRR1 represents a novel actin-tubulin bridging protein that plays important roles in cytoskeletal events
Phenotypic analyses of PTP-PEST null cells and gene targeting of its substrate, p130cas
No full textTo understand the physiological role of the protein tyrosine phosphatase (PTP) PEST, the phenotypes of PTP-PEST (--/--) mouse fibroblasts have been studied PTP-PEST was shown to translocate to the membrane periphery following stimulation by the extracellular matrix protein fibronectin, and to play a role in cell migration, spreading, and cytokinesis. For this action, PTP-PEST was shown to regulate the phosphorylation levels of p130cas, paxillin, FAK and PSTPIP, and their association with SH2 domain-containing proteins like Src and Crk. From these proteins, p130cas is known to be a direct substrate. Experiments for the obtention of p130cas (--/--) embryos and cell lines have also been initiated, up to the generation of adult chimeric animals. In the process, a genomic fragment of p130cas containing a C-terminal exon has been cloned and analysed
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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