1,721,044 research outputs found
62 POSTER Expression and functional activity of interleukin-8 receptors on human malignant melanoma cells
No full textEffects of antimetastatic dimethyltriazenes in mice bearing Lewis lung carcinoma lines with different metastatic potential
No full textThe effects of 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide (DTIC) and its benzenoid analog p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) have been examined in mice bearing two Lewis lung carcinoma lines with different potential to spontaneously metastasize to the lungs. DTIC similarly depresses the growth of intramuscular and pulmonary tumor nodules, and also reduces the development of spontaneous lung metastases for both tumor lines. DM-COOK causes effects similar to those of DTIC on the tumor line with low metastatic potential; on the contrary, although it is highly active in inhibiting lung metastasis formation for the line with high metastatic potential, it is ineffective or marginally cytotoxic on intramuscular or on pulmonary tumor nodules, respectively. These data indicate, at least for the dimethyltriazene DM-COOK, a dissociation between sensitivity to cytotoxic and antimetastatic effects, and that tumor cell populations with a higher potential to spontaneously metastasize have a greater sensitivity to selective antimetastatic effects, concomitant with a reduced cytotoxic response to the effects of this drug
Inhibition of leukaemia cell proliferation by folic acid-polylysine-mediated introduction of c-myb antisense oligodeoxynucleotides into HL-60 cells.
No full textThe inhibitory effect of c-myb antisense oligodeoxynucleotides (ODNs) conjugated to folic acid (FA) on HL-60 cell proliferation was examined. Folic acid was covalently linked to a polylysine chain and purified by gel chromatography. Sterile FA-polylysine was complexed with c-myb sense and antisense. Exposure of HL-60 cells to the FA-polylysine-c-myb antisense ODN complex resulted in a down-regulation of c-myb expression and a greater inhibition of proliferation than that obtained using free ODNs. Moreover, FA-polylysine conjugate alone or complexed to c-myb sense ODN was not toxic to cells. The antigenic properties and uptake of the vitamin were not affected by the polylysine chain. These data suggest that this strategy is potentially useful for the selective delivery of anti-oncogene-targeted ODNs into cancer cell
N-methylformamide effects on cell proliferation and antigenic pattern in HT-29 colon carcinoma cell line.
No full textBcl-2 has differing effects on the sensitivity of breast cancer cells depending on the antineoplastic drug used
No full textThe aim of this paper was to evaluate the role of bcl-2 in the susceptibility of the MCF7 ADR human breast carcinoma line overexpressing the P-170 glycoprotein (P-170) to various drugs. The sensitivity to four multidrug resistance (MDR)-related drugs (doxorubicin (ADR), vincristine (VCR), vinblastine (VBL), actinomycin D (ACTD)) and three MDR-non-related drugs (cisplatin (DDP), bischloroethylnitrosourea (BCNU), 5-fluorouracil (5-FU)) was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay in three bcl-2-overexpressing clones obtained from the MCF7 ADR line. We found that the bcl-2-overexpressing clones show increased resistance to DDP and BCNU, while no difference to 5-FU were observed between the control cells and bcl-2 transfectants. Surprisingly, bcl-2-overexpressing clones displayed an increased sensitivity compared with the control cells to the MDR-related drugs ADR, VCR, VBL and ACTD. Focusing on DDP and ADR, we found that the increased resistance of the bcl-2 transfectants to DDP was correlated to their ability to prevent apoptosis, while the enhanced sensitivity to ADR was associated with an increased ADR accumulation and a decreased ADR efflux. Moreover, while bcl-2 overexpression does not induce changes in P-170 glycoprotein expression, it did induce a reduction of the adenosine triphosphate (ATP) levels and basal protein kinase C (PKC) activity, both of which have a crucial role in the regulation of the MDR phenotype. In conclusion, the effect of bcl-2 on antineoplastic sensitivity observed in this study underscores the idea that bcl-2 may have distinct biological effects depending on the anticancer drug used. © 2002 Elsevier Science Ltd. All rights reserved
Involvement of RB gene family in tumor angiogenesis
No full textAngiogenesis, the development of new blood vessels from pre-existing vessels, represents a fundamental step in tumor progression and metastatization. The induction of vasculature is required for growth of the tumor mass, to ensure an adequate supply of oxygen and metabolites to the tumor beyond a critical size. Tumor angiogenesis is a highly regulated process that is controlled physiologically by the tumor microenvironment and genetically by alteration of several oncogenes or tumor suppressor genes. We will focus on recent demonstrations regarding the involvement of the retinoblastoma family proteins (phosphorylated retinoblastoma (pRb), p107 and pRb2/p130) at different levels of the angiogenic process. pRb and its homologs can regulate the expression of pro- and antiangiogenic factors, such as the vascular endothelial growth factor, through an E2F-dependent mechanism. Moreover, pRb is able to modulate also the transcriptional activity of several angiogenesis-related factors like HIF-1, Id2 and Oct-1. pRb2/p130 is required for both differentiation and mobilization of bone marrow-derived endothelial cell precursors and endothelial sprouting from neighboring vessels. The involvement of the pRb pathway in the angiogenesis process has also been demonstrated by different cellular models expressing viral oncoproteins, like human papilloma virus. Moreover, some natural and synthetic compounds demonstrate their antiangiogenetic activity with a mechanism of action involving pRb. Finally, the possible prognostic value of immunohistochemical evaluation of pRb and/or pRb2/p130 expression can represent a useful tool for the characterization of the angiogenic phenotype of specific tumor histotypes. © 2006 Nature Publishing Group All rights reserved
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
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