1,721,048 research outputs found
INCREASED APOPTOSIS AS A MECHANISM OF INEFFECTIVE ERYTHROPOIESIS IN MYELODYSPLASTIC SYNDROMES
No full textClassification and prognostic evaluation of myelodysplastic syndromes
No full textMyelodysplastic syndromes (MDS) are myeloid neoplasms characterized by dysplasia in one or more cell lines and increased risk of development of acute myeloid leukemia (AML). The current diagnostic approach to MDS includes peripheral blood and bone marrow morphology to evaluate abnormalities of peripheral blood cells and hematopoietic precursors; bone marrow biopsy to assess marrow cellularity, fibrosis, and topography; and cytogenetics to identify non-random chromosomal abnormalities. The 2008 World Health Organization (WHO) classification currently provides the best diagnostic approach to MDS and also has considerable prognostic relevance. The WHO classification-based prognostic scoring system (WPSS) is able to classify MDS patients into five risk groups showing different survivals and probabilities of leukemic evolution. The WPSS is able to predict survival and leukemia progression at any time during follow-up, and can therefore be used for implementing risk-adapted treatment strategies in patients with primary MDS. Since comorbidities have a significant impact on the outcome of patients with MDS, accounting for both disease status and comorbid conditions considerably improves risk stratification
Apoptosis in relation to CD34 antigen expression in normal and myelodysplastic bone marrow.
No full textAn increased bone marrow (BM) apoptosis is one of the mechanisms responsible for the ineffective hematopoiesis of myelodysplastic syndromes (MDS). It is controversial whether the excessive apoptosis in myelodysplasia predominantly involves the subset of progenitor cells or of maturing cells. We investigated the degree of apoptosis in MDS BM and its differences from normal marrow in relation to CD34 antigen expression. A double-labelling technique that combined the Tdt-mediated dUTP nick end labelling (TUNEL) method with immunocytochemistry for CD34 antigen was used on BM slides of 18 MDS patients and 11 controls. The apoptotic rate (AR) appeared significantly higher in CD34-negative than in CD34-positive cell subsets both in myelodysplastic and in normal BM. When MDS and normal CD34-negative cell populations were compared, a greater AR in MDS CD34-negative cells was found, while no statistical difference in AR resulted from the comparison between MDS and normal CD34-positive cell populations. Our results suggest that in myelodysplastic as well as in normal BM the apoptotic phenomenon predominantly involves the maturing cells. The increase in apoptotic levels which can be observed in myelodysplastic compared to normal BM seems to be mainly due to an increase in apoptosis in the differentiated cell 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
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