1,720,961 research outputs found
[The cell-mediated response after measles vaccination]. STUDIO DELLA RISPOSTA CELLULO-MEDIATA DOPO VACCINAZIONE ANTI-MORBILLOSA
No full textNatural measles virus infection is recognized for causing prolonged abnormalities in immune responses, that contribute to the severe and complicated evolution of the disease. Immunization with live measles virus vaccine could be considered a mild form of the measles infection. Results of investigation of in vitro immune response after measles immunization with live attenuate vaccine have been conflicting. In this work we studied cellular immune parameters in children aged between 3 and 12 years. T cells, CD4+ and CD8+ subsets were analyzed by cytometry. CD3+ cells were significantly reduced compared to controls (p < 0.01) whereas CD4+/CD8+ ratio was normal. The in vitro proliferative response to polyclonal mitogen was significantly reduced (p < 0.01). This study confirms the presence of a mainly functional immunosuppression of cellular response in a cohort of children belonging to a developed area. These findings improve the understanding of the mechanism of immune response to virus measles and provide suggestions for the development of a better approach to immunization, taking account for the strain, vaccine titre, age and environmental conditions of the target population
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
Dispelling 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
The challenge of culturing human colorectal tumor cells: establishment of a cell culture model by the comparison of different methodological approaches
No full textBACKGROUND: Because colorectal cancer is a significant cause of morbidity and mortality in the Western population, knowledge of the molecular and biological alterations associated with its development is important. Since primary human colon cancer cultures from fresh tumor tissue are technically difficult to obtain, experiments in most laboratories are performed on colon epithelial cell lines, but these represent just one stage of tumor progression. Only primary cultures of neoplastic colonocytes may reflect the actual responsiveness of tumors at certain developmental stages to antitumor agents.
METHODS: This paper analyzes several critical points concerning primary cultures, ranging from cell isolation to culture conditions, and compares different methodological approaches to isolate and cultivate a pure fraction of viable tumor cells. Samples of resected colorectal cancers were collected from 20 patients (stage T3 or T4). We compared in vitro several approaches of tissue disaggregation including mechanical disaggregation and enzymatic dissociation with trypsin or collagenase. Isolated cells were maintained in a short-term serum-free culture system. Evaluation of the purity and tumoral nature of isolated cells was performed by immunochemistry.
RESULTS: We established the antibiotic concentration necessary during transport and washing of the specimens to prevent microbial overgrowth. We demonstrated that the number of viable cells was dependent on the dissociation method used. Mechanical disaggregation is not a valid dissociation method because of the high mortality of cells and might be used only in samples for molecular analysis. Comparison of the enzymatic digestion procedures showed that digestion with trypsin allowed the highest recovery of viable cells.
CONCLUSION: In this paper we analyzed several critical aspects of cell culture procedures and designed a methodological approach suitable for functional studies of colorectal cance
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