1,720,965 research outputs found
Regulation of tumor antigen expression by drugs acting as mutagens and/or gene activators.
No full textDNA methylating activity in murine lymphoma cells xenogenized by triazene derivatives.
No full textWe investigated whether epigenetic rather than mutational events may be involved in the induction of novel immunogenicity ("xenogenization") in murine lymphoma treated with triazene derivatives. To this end, we assessed the DNA methylation pattern of tumor cells during the course of in vivo or in vitro xenogenization by 2 triazenes, and compared it with the changes induced by the DNA hypomethylating agent 5-azacytidine (5-aza). While all of the tested agents were able to increase tumor cell immunogenicity, their effects on DNA methylating activity were opposite. In particular, the novel immunogenicity conferred by 5-aza treatment correlated well with the extent of hypomethylation induced, whereas xenogenization by triazenes was accompanied by a limited increase in DNA methylating activity. Interestingly, the antimutagenic compound quinacrine, which is known to block the xenogenizing activity of triazenes, was incapable of hypermethylating effects, whereas the hypermethylating agent cytosine arabinoside (ara-C) was apparently unable to interfere with the induction of novel immunogenicity by triazene
Combined effects of host antitumor immune responses and chemotherapy. Studies with hexamethylmelamine.
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Changes in the tumorigenic and metastatic properties of murine melanoma cells treated with a triazene derivative.
No full textTreatment of B16/BL6 murine melanoma cells in vitro with the 'xenogenizing' agent potassium p-(3-methyl-1-triazeno)benzoate (MM-COOK) had a profound impact on the tumorigenic and metastatic properties of the tumor, an effect that was only detectable in immunologically intact hosts. The treated tumor cells gave rise to a considerably smaller number of experimental and spontaneous pulmonary metastases and displayed an impaired growth rate in vivo, but were highly tumorigenic and metastatic in irradiated recipients. Moreover, the drug-treated cells retained the in vitro growth pattern and plating efficiency of the parent line, and were able actively to immunize intact hosts. Studies aimed at clarifying the mechanisms responsible for the decreased metastatic potential of the cells treated with MM-COOK indicated the involvement of host immune responses largely mediated by cells in the T-dependent compartment with no major contribution of natural immunity effector mechanisms
Platelet-tumor cell interaction: effect of prostacyclin and a synthetic analog on metastasis formation.
No full textEffects of a stable prostacyclin analogue on platelet activity and on host immunocompetence in mice.
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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
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