1,720,975 research outputs found
CXCL12 does not attract CXCR4(+) human metastatic neuroblastoma cells: Clinical implications
No full textPURPOSE: The role of CXCR4 in bone marrow localization of neuroblastoma cells has been recently proposed. The aim of this study was to investigate the expression and chemotactic functionality of CXCR4 in human metastatic neuroblastoma cells isolated from the bone marrow and, for comparison, in a panel of neuroblastoma cell lines.
EXPERIMENTAL DESIGN: CXCR4 expression and chemotactic functionality were investigated in metastatic neuroblastoma cells isolated from patient bone marrow and in neuroblastoma cell lines. The former cells were isolated as CD45- or GD2+ cells by immunomagnetic bead manipulation. Chemotactic assays were done in a transwell system. Regulator of G protein signaling expression was investigated by reverse transcription-PCR.
RESULTS: Metastatic neuroblastoma cells consistently expressed CXCR4, which was also detected in 5 of 10 neuroblastoma cell lines. CXCL12 did not stimulate the chemotaxis of primary tumor cells or cell lines in either normoxia or hypoxia, irrespective of CXCR4 up-regulation detected under the latter condition. Accordingly, neuroblastoma cells failed to modulate filamentous actin and to activate mitogen-activated protein kinase upon treatment with CXCL12. RGS16 mRNA was consistently expressed in primary tumor cells and cell lines, but its down-regulation by RNA interference did not restore CXCR4 chemotactic functionality.
CONCLUSIONS: These results show unambiguously that CXCR4 expressed in human metastatic neuroblastoma cells is not functional and do not support the clinical use of CXCR4 antagonists to prevent neuroblastoma metastasis
Natural killer cell-mediated killing of freshly isolated neuroblastoma cells: critical role of DNAX accessory molecule-1-poliovirus receptor interaction
No full textIn the present study, we assessed the susceptibility of freshly isolated neuroblastoma cells to killing mediated by normal human natural killer (NK) cells and analyzed the receptor-ligand interactions that regulate this event. We show that killing of freshly isolated neuroblasts, similar to neuroblastoma cell lines, involves NKp46 and NKp30 (natural cytotoxicity receptors). However, freshly isolated neuroblasts were generally more resistant to NK-mediated lysis than conventional neuroblastoma cell lines. Moreover, a significant heterogeneity in susceptibility to lysis existed among neuroblastomas derived from different patients. Remarkably, susceptibility to lysis directly correlated with the surface expression, on neuroblasts, of poliovirus receptor [PVR (CD155)], a ligand for the DNAX accessory molecule-1 [DNAM-1 (CD226)] triggering receptor expressed by NK cells. Indeed, PVR-expressing neuroblastomas were efficiently killed by NK cells. Moreover, monoclonal antibody-mediated masking of either DNAM-1 (on NK cells) or PVR (on neuroblasts) resulted in strong inhibition of tumor cell lysis. Thus, assessment of the PVR surface levels may represent a novel useful criterion to predict the susceptibility/resistance of neuroblastomas to NK-mediated killing
Characterization and tumorigenicity of human neuroblastoma cells transfected with the IL-2 gene.
No full textSmall round blue cell tumours: diagnostic and prognostic usefulness of the expression of B7-H3 surface molecule.
No full textAIMS:
To assess whether the expression of B7-H3 surface molecule could improve differential diagnosis of small cell round tumours.
METHODS AND RESULTS:
One hundred and one well-characterized paraffin-embedded small round cell tumours, stored in the pathology archive of the Gaslini Institute, were immunohistochemically analysed with the 5B14 monoclonal antibody, which recognizes the surface molecule B7-H3. All lymphoblastic lymphomas and the blastematous component of Wilms' tumours were completely negative and a few Ewing's sarcoma and Burkitt's lymphoma specimens showed focal positivity, whereas 74% of neuroblastomas, 67% of rhabdomyosarcomas and 100% of medulloblastomas were positive. The pattern of immunoreactivity of 5B14 mAb observed in rhabdomyosarcoma, neuroblastoma and medulloblastoma specimens was limited to the cytoplasmic membrane, and in neuroblastomas areas of rosette formation or of ganglion differentiation were preferentially stained. Interestingly, in neuroblastoma patients high expression of the antigen recognized by the 5B14 mAb was associated with a worse event-free survival.
CONCLUSIONS:
The 5B14 mAb represents an additional tool for the differential diagnosis of small round cell tumours and might be useful in identifying neuroblastoma patients at risk of relapse who may take advantage of more careful follow-up
Angiogenesis in a human neuroblastoma xenograft model: mechanisms and inhibition by tumour-derived interferon-gamma
No full text
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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