1,721,066 research outputs found
Temozolomide reduces the metastatic potential of Lewis-lung-carcinoma (3ll) in mice: role of alpha-6 integrin phosphorylation
No full textThe involvement of protein kinase c (PKC) in the mechanism underlying the antimetastatic properties of triazenes was studied in C57BL/6 mice bearing Lewis lung carcinoma (3LL). In vivo and in vitro treatment with temozolomide, an in-vitro active analogue of dacarbazine, or calphostin c produced a concentration-dependent reduction of spontaneous and artificial metastases. Both agents reduced the ability of 3LL cells to adhere to endothelium. Diethylaminoethyl (DEAE)-sepharose chromatography of cell extracts revealed that incubation of 3LL cells with 12-0-tetradecanoylphorbol-13-acetate (TPA) caused a rapid translocation of protein kinase c activity from cytosol to the membrane fraction. Membrane PKC activity induced by TPA was reduced by 60% after treatment with temozolomide. Coincident with these changes, TPA induced phosphorylation of alpha-6 integrin, whereas temozolomide or calphostin c abolished the appearance of this phosphoprotein. These results suggest that temozolomide reduced metastatic potential by interfering with alpha-6 phosphorylation induced by PKC activation
Antitumor and antimetastatic effects of dacarbazine combined with cyclophosphamide and interleukin-2 in Lewis lung carcinoma (3LL)
No full textThe antitumor and antimetastatic activity of dacarbazine (DTIC) alone or in combination with cyclo-phosphamide (CY) was tested in C57BL/6 mice bearing Lewis lung carcinoma (3LL). Treatment with both agents significantly reduced tumor growth and the number of metastases. These effects were associated with marked changes of the biochemical and immunological properties of drug-treated 3LL cells, i.e. (a) reduction of alpha 6 integrin expression, (b) increased susceptibility to natural immunity in vivo, as measured in terms of rapid clearance from mouse lungs of prelabeled 3LL cells injected i.v. and (c) increased immunogenicity, as assessed by T-cell-mediated immune responses (i.e. graft rejection by intact syngeneic mice, and frequency of specific CTL precursors recognizing DTIC/CY-treated cancer cells). The immunotherapeutic advantage afforded by increased immunosensitivity and immunogenicity of 3LL cells exposed to DTIC+CY appears to be markedly reduced in vivo by the profound immunodepressive effects of these drugs. Within this context, addition of interleukin-2 was found to increase the antitumor and antimetastatic activity of this chemotherapeutic regimen. The present study shows, for the first time in a solid tumor model, that a biological response modifier increases the antitumor efficacy of drugs that are able to affect the immunological properties of cancer cells
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
N-methylformamide effects on cell proliferation and antigenic pattern in HT-29 colon carcinoma cell line.
No full textDispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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