1,720,984 research outputs found
“In vitro” evaluation of bone marrow angiogenesis in myelodysplastic syndromes: a morphological and functional approach
No full textIn myelodysplastic syndromes (MDS), ineffective hematopoiesis and cytopenia may arise either from increased susceptibility to apoptosis of hematopoietic cells, or possibly from alterations of bone marrow stroma that contributes to defective development of marrow lineages. In order to test the significance of the endothelial growth in MDS patients, two in vitro assays are presented in this study: a long-term culture method for the detection of human bone marrow endothelial colonies (CFU-En) (77 patients) and a human primary model for the evaluation of the influence of a "bone marrow conditioned medium" on the formation of new vessels in a culture matrix ("angio-kit assay") (in 24 out 77 patients). The in vitro growth pattern of bone marrow CFU-En as well as the generation of microvessels in the angio-kit system was increased in RA, RARS and RAEB in comparison with controls. No CFU-En were detected in RAEB-T. The occurrence of large islands, formed by clusters of endothelial cells, unable to generate microcapillaries was also reported. Chromosomal abnormalities did not correlate with the angiogenetic pattern. These in vitro assays may constitute an useful approach to the analysis of angiogenesis in MDS
Abnormalities of chromosomes 1p34-36, 4p16, 4q35, 9q11-32 and +7 represent novel recurrent cytogenetic rearrangements in chronic lymphocytic leukemia
No full textKaryotypes were studied in over 250 cases of CLL seen at our Institution and 12 cases with a previously undescribed chromosome abnormality were identified. Cytogenetic and clinicobiological features in these patients are described. Fluorescence in situ hybridization using probes for the detection of +12 and deletions of 13q14, 17p13, and 11q22-23 was performed. Hematologic and clinical data were reviewed and a review of the literature was performed. Twelve patients were found carrying the following aberrations in the stemline: abnormalities at 1p34 (n = 2), 4p16 (n = 2), 4q35 (n = 2), 9q11-32 (n = 4) and +7 (n = 2). Trisomy 12 was found in 3 cases, whereas no case carried 13q-, 11q-, 17p-. Our data showed that (i) aberrations involving 1p34 and 4p16 as isolated chromosome anomalies were preferentially associated with early stage disease; (ii) 4q35 anomalies were associated with a relatively aggressive disease, atypical morphology and with monoclonal gammopathy; (iii) rearrangements of 9q were characterized by atypical morphology and aggressive disease with splenic involvement; (iv) +7 be may associated with +12. 1p34-36; 4p16; 4q35; 9q and chromosome 7 represent novel recurrent rearranged sites in CLL, with a 0.5-3% incidence. Transformation in these patients seemingly occured through a cytogenetic route not involving the classical CLL-associated chromosome regions. These chromosome rearrangements may be associated with peculiar hematologic features
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
Cytogenetic and molecular cytogenetic profile of bone marrow-derived mesenchymal stromal cells in chronic and acute lymphoproliferative disorders
No full textThe possibility that human mesenchymal stromal cells (hMSC) may derive from the malignant clone in hematological malignancies (HM) is a controversial issue. In order to clarify hMSC origin and disclose possible cytogenetic heterogeneity in hMSC belonging to different patients, bone marrow (BM)-derived hMSC samples from chronic lymphocytic leukemia (CLL) and acute lymphoblastic leukemia (ALL) were expanded in culture, characterized by flow cytometry, and screened by conventional cytogenetic analysis and fluorescent in situ hybridization for the presence of possible cytogenetic aberrations, related or not to the hematopoietic neoplastic clone. Our data showed that the presence of cytogenetic aberrations in successfully expanded HM-MSC stromal layers derives from the persistence of contaminating hemopoietic cells (HC), which is greatly supported by in vitro culture conditions that could mimic in vivo microenvironmental niche. Interestingly, the presence of binucleated HM-MSC maintaining a diploid numerical setting has been also detected, while aneuploidies were observed more frequently in mononucleated HM-MSC from patients with an altered karyotype than in patients with a normal karyotype and controls. In conclusion, here,we showed that in ALL and in CLL, the BM-MSC has a normal karyotype, thus supporting a distinct origin from hematopoietic cells (HC). The presence of in vitro hMSC aneuploidy is associated with lymphoid neoplasias carrying chromosome abnormalities, suggesting that hMSC should be characterized before clinical application. The adequacy of hMSC cytogenetic characterization here proposed could represent a "prerequisite" to standardize the hMSC analysis before their use in the autologous setting and cellular therapy. © Springer-Verlag 2012
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
Alterazioni cromosomiche in cellule staminali emopoietiche indotte da esposizioni ambientali o professionali.
No full textAlterazioni cromosomiche in cellule staminali emopoietiche indotte da esposizioni ambientali o professional
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