1,721,010 research outputs found
Cytogenetics and molecular genetics of acute lymphoblastic leukemia
No full textAn important factor in the diagnosis of acute lymphoblastic leukemia (ALL) is that karyotype is an independent prognostic indicator, with an impact on the choice of treatment. Outcome is related to the number of chromosomes. For example, high hyperdiploidy (51–65 chromosomes) is associated with a good prognosis, whereas patients with near haploidy (23–29 chromosomes) have a poor outcome. The discovery of recurring chromosomal abnormalities in the leukemic blasts of patients with ALL has identified a large number of genes involved in leukemogenesis. Certain specific genetic changes are related to prognosis. The ETV6/AML1 fusion arising from the translocation (t12;21) (p13;q22) has been associated with a good outcome; the BCR/ABL fusion of (t9;22)(q34;q11), rearrangements of the MLL gene, and abnormalities of the short arm of chromosomes 9 involving the tumor suppressor genes p16INK4A have a poor prognosis. Unfortunately, the classification of patients into prognostic groups based on cytogenetics is not always as predicted. Even when other clinically based risk factors are taken into account, some patients with good-risk cytogenetic features will relapse. In the search for new measures of prognosis, it has recently emerged that the level of minimal residual disease following induction therapy can be a reliable predictor of outcome in ALL
A fluorescence in situ hybridization map of 6q deletions in acute lymphocytic leukemia: identification and analysis of a candidate tumor suppressor gene
No full textWith the objective of identifying candidate tumor suppressor genes, we used fluorescence in situ hybridization to map leukemia-related deletions of the long arm of chromosome 6 (6q). Twenty of 24 deletions overlapped to define a 4.8-Mb region of minimal deletion between markers D6S1510 and D6S1692 within chromosome 6 band q16. Using reverse transcription-PCR, we found evidence of expression in hematopoietic cells for 3 of 15 genes in the region (GRIK2, C6orf111, and CCNC). Comparison between our own and published deletion data singled out GRIK2 as the gene most frequently affected by deletions of 6q in acute lymphocytic leukemia (ALL). Sequence analysis of GRIK2 in 14 ALL cases carrying heterozygous 6q deletions revealed a constitutional and paternally inherited C to G substitution in exon 6 encoding for an amino acid change in one patient. The substitution was absent among 232 normal alleles tested, leaving open the possibility that heterozygous carriers of such mutations may be susceptible to ALL. Although low in all normal hematopoietic tissues, quantitative reverse transcription-PCR showed higher baseline GRIK2 expression in thymus and T cells than other lineages. Among T-cell ALL patients, 6q deletion was associated with a statistically significant reduction in GRIK2 expression (P = 0.0001). By contrast, elevated GRIK2 expression was measured in the myelomonocytic line THP-1 and in one patient with common ALL. Finally, we detected significant levels of GRIK2 expression in prostate, kidney, trachea, and lung, raising the possibility that this gene may be protective against multiple tumor types
Fast-mode duplex qPCR for BCR-ABL1 molecular monitoring: Innovation, automation, and harmonization
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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