1,721,087 research outputs found
Functional differences between dendritic cells derived from CD34+ bone marrow and peripheral blood stem cells
No full textBackground and Objectives. It has been previously demonstrated that dendritic cells (DCs) are characterized by an immature stage with high antigen internalization capacity, followed by a mature stage with predominantly immunostimulatory ability. The shift from the immature to the mature state can be induced in vitro by the addition of tumor necrosis factor-α (TNFα). The aim of our study was to investigate the maturation steps of DCs obtained from CD34+ cells from peripheral blood stem cells (PBSC) and bone marrow (BM). Design and Methods. DCs were generated in vitro from PBSC and BM CD34+ selected cells. The endocytic activity of the cells was measured by means of dextran-FITC uptake and alloreactivity evaluated with mixed leukocyte reactions. Immunophenotypic analysis was performed by flow cytometry. Results. We observed that DCs from PBSC, in contrast to the BM derived DCs, were never able to take up soluble antigens. Mixed leukocyte reaction (MLR) performed both on PBSC and BM CD34+ derived DCs showed an allo-stimulatory activity comparable to normal controls at day 10, but significantly higher at day 14 after the addition of TNFα. Immunophenotypic analysis showed typical dendritic markers in all the samples and, after treatment with TNFα, enhanced expression of co-stimulatory molecules. Interpretation and Conclusions. Our data seem to indicate that, in our culture conditions. BM-derived DCs could be efficiently used for pulsing with specific peptides, while PBSC-derived DC, being functionally mature, should be more suitable for gene therapy. (C) 2000, Ferrata Storti Foundation
Non-generic concentrations for shape-memory alloys; the case of CuZnAl
No full textAs is well known, the remarkable properties of many active crystalline materials, such as shape-memory alloys, originate from a symmetry-breaking martensitic phase transformation. A recent analysis (see Pitteri and Zanzotto, Acta mater., 1998, 46, 225) has shown that if a special condition on the strain parameters is satisfied, the twinning ability of a crystal undergoing a cubic-to-monoclinic transformation is considerably increased. As this feature may improve the memory behavior of cubic–monoclinic alloys, it is suggested that these predictions be tested experimentally. A procedure is given to determine explicitly which “non-generic” concentrations allow suitable alloys to produce the extra twins; which concentrations give a volume-preserving transformation are also determined (this condition guarantees self-accommodation of the martensite). As an example, the ternary CuZnAl system is considered, for which, based on the available experimental data, the non-generic concentrations are established. The work indicates that there is a scarcity of the necessary data on the mapping of lattice parameters vs concentrations in alloys with a potential for shape memory. A specific experimental program aiming at the systematic gathering of this information is proposed: building such a database may prove of considerable help in the search and synthesis of new materials with improved performance
The diagnostic and prognostic value of bone marrow immunostaining in myelodysplastic syndromes
No full textImmunohistochemistry has been introduced as a means of increasing the diagnostic accuracy of bone marrow biopsy (BMB) in myelodysplastic syndromes (MDS); more recently the possibility of coupling immunostaining with other investigational techniques has broadened the spectrum of applications to the biology and physiopathology of MDS. Using panels of monoclonal antibodies (MoAbs), various histological classifications of MDS have been proposed as an alternative to the FAB criteria. The use of Lineage-specific MoAbs has allowed a deeper insight into the dysplastic features of early hematopoietic precursors. The study of various gene products involved in the regulation of cell growth, proliferation and sensitivity to antineoplastic drugs, has revealed significant differences between MDS and morphologically-related disorders, particularly acute myelogenous leukemias (AML); these can be considered markers of a biological difference between the two groups of disorders and deserve consideration when designing therapeutic strategies for MDS, Both an increase in the percentage of cell positivity for the CD34 glycoprotein and a tendency of positive cells towards forming aggregates have been shown to be reliable predictors of leukemic transformation and survival, irrespective of the FAB subtype; furthermore, CD34 positivity has also proved to be a better prognostic factor than the presence of the abnormal localization of immature precursors (ALIP) on BMB. Finally, the simultaneous occurrence of 'large' and CD34 positive aggregates can be proposed as a means of recognizing MDS patients with an exceedingly unfavourable prognosis, and who are therefore suitable for early aggressive therapy
Oral malignancies following HSCT : graft versus host disease and other risk factors
No full textAllogenic hematopoietic stem cell transplantation (HSCT), a procedure that is widely used in the treatment of a large number of malignant and nonmalignant hematological diseases, is still associated with a wide range of complications, one of the most important of which is graft versus host disease (GVHD). The patients undergoing allogenic HSCT are also at high risk of developing secondary neoplasms, particularly leukemias and lymphomas. Solid tumors are less frequent, and the incidence appears to increase over time; the most frequent solid tumors are squamous cell carcinomas. We found that almost all studies of solid cancers occurring after transplantation are based on relatively small numbers of cases which have been monitored for short periods, and little information is available on individual cancers. In particular, reports of oral cancers in HSCT are very few. Potential risk factors associated with the development of secondary solid cancers after HSCT have been well described. They include graft versus host disease (GVHD), preoperative regimens, with either radio-chemotherapy or chemotherapy alone, conditioning regimes, immunosuppressive GVHD prophylaxis, viral infection and chronic stimulation as a result of viral antigens, antigenic stimulation from histocompatibility differences between recipient and donor, primary diagnosis, interaction of any of these factors with genetic predisposition, and other factors such as sex and age. All patients treated with HSCT should therefore be closely followed over the long term with the aim of identifying the onset of secondary tumors as early as possible. (c) 2005 Elsevier Ltd. All rights reserved
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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