1,721,101 research outputs found
Régulation transcriptionnelle du gène suppresseur de tumeur "brca2" chez la souris
No full textDoctorat en sciences médicalesinfo:eu-repo/semantics/nonPublishe
Influence of L-thyroxine, L-triiodothyronine, thyroid stimulating hormone, or estradiol on the cell kinetics of cultured mammary cancer cells.
No full textWe describe the in vitro influence of 3,5,3'-triiodo-L-thyronine (T3), L-thyroxine (T4), a thyroid-stimulating hormone (TSH), and/or estradiol (E2: chosen as the control of the methodology) on the cell kinetics (cell distribution in the S + G2 + M phases) of mouse MXT and human MCF-7 mammary cancer cells. Experiments were performed by means of a cell image processor, analyzing MCF-7 or MXT cells that had been grown on glass cover slips and whose nuclei had been stained by the Feulgen reaction, which is selective and quantitative (stoichiometric) with respect to DNA. We show that T3, T4, and TSH at 0.01 microM dramatically stimulate the cell kinetics of the MXT mouse and the MCF-7 human mammary cancer cell lines. Indeed, the three hormones bring about a significant transient increase in the S + G2 + M fraction as does E2. Furthermore, our data indicate that E2 and TSH are antagonistic with regards to MXT or MCF-7 cell kinetics.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
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
In vivo relationship between morphonuclear parameters and hormone sensitivity of the murine MXT mammary tumor.
No full textThe initially hormonosensitive (HS) MXT mouse mammary tumor spontaneously evolved to hormonoin-dependence (HI). Using a SAMBA 200 cell image processor, we compared the DNA content and the chromatin structure of HS and HI tumor cells squashed onto histologic slides; the nuclei were colored by the Feulgen reaction. We compared HI and HS nuclei by a discriminant analysis using the 15 parameters obtained on each nucleus. We show that the percentage of well-classified granulocytes (2n DNA content control) versus HS or HI nuclei exceeded 99. On the other hand, this percentage did not reach 70 when we compared HS and HI. The cell cycle analysis revealed that the percentage of cells in S and G2 + M phases were significantly higher in HI tumors than in the HS. Hence, HI and HS MXT tumor nuclei seem to be morphologically identical, but are significantly different if we refer to cell proliferation rates.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
In vivo influence of androgens on the cell kinetics and chromatin pattern of the MXT mouse mammary tumor treated or not by aminoglutethimide.
No full textWe characterized the influence of androstenedione, 5-alpha-dihydrotestosterone and 17-beta-estradiol on the chromatin organization and the cell kinetics (distribution of the cells into the G0-G1, S and G2+ M fractions) of MXT mouse mammary tumors grafted onto animals that were left intact or that were oophorectomized and/or treated with aminoglutethimide. The cell kinetics and chromatin pattern were monitored by analyzing Feulgen-stained MXT imprint smears through a cell image processor, the SAMBA 200 system. We have also assayed the estrogen and progesterone receptors of these MXT tumors, which appeared to possess both of these biological markers. Our results show that ovariectomy or aminoglutethimide treatment slowed down the MXT tumor growth without any additive effect between them. Androstenedione exerted a stimulating influence on the cell kinetics, which were very similar to those observed after estradiol administration; the treatment of castrated animals with aminoglutethimide completely abolished this androstenedione-induced stimulating influence, however. This androgen lacked any apparent efficiency to transform cell nuclei from a state of castration-induced chromatin condensation into a thinly textured and decondensed state, as did estradiol. Dihydrotestosterone was able to activate the cell kinetics of MXT tumor grafted onto castrated animals as well as those of MXT neoplasms grafted on oophorectomized mice treated with aminoglutethimide. Dihydrotestosterone also possesses the property to transform condensed chromatin into decondensed chromatin. It thus appeared that androstenedione and dihydrotestosterone could activate MXT cell proliferation, as did estradiol, although it appeared that their mechanisms of action were quite distinct from each other.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
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
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