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    Ladetto, Marco

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    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Hematopoietic Stem Cells (HSC) and Granulocyte Macrophage Progenitors (GMP) are the Oxidative Stress Targets in Low/Intermediate-1 Risk Myelodysplastic Syndromes

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    INTRODUCTION: Myelodysplastic Syndromes (MDS) are a heterogenous group of clonal hematopoietic stem cell malignancies. Previous studies showed that Reactive Oxygen Species (ROS) play a role in the pathogenesis and clinical evolution of MDS, contributing to Hematopoietic Stem and Progenitor Cells (HSPC) genetic instability. Less is known about ROS levels in the various sub-populations of MDS HSPC and how they correlate with clinical data in MDS patients. Our study aims to analyze ROS levels in MDS Hematopoietic Stem Cells (HSC), common myeloid progenitors (CMP), Granulocyte Macrophages Progenitors (GMP) and megakaryocyte-erythrocyte progenitors (MEP); afterwards, we looked at the relationship between ROS levels and clinical data. METHODS: thirty-eight MDS and 27 Normal Bone Marrow (NBM) samples were collected; ROS levels were analyzed via multicolor flow cytometry. RESULTS: In both NBM and MDS, HSC showed much higher ROS levels than progenitors (3 to 4 folds, p < 0.0001); HSC ROS were significantly more elevated in MDS-no excess blasts versus MDS with excess blasts and versus NBM. GMP from MDS-no excess blasts showed higher ROS compared to NBM GMP. The 3 MDS with Ringed Sideroblasts (RS) showed more elevated ROS in HSC and GMP compared to the not RS low/intermediate-1 MDS; the 2 monosomy 7 patients displayed higher ROS levels in each subpopulation compared to the normal karyotype MDS; the only del(5q) patient did not show relevant differences in ROS levels compared to the median of the normal karyotype MDS ROS. The 9 high transfusion burden patients exhibited higher ROS in HSC and GMP compared to NBM HSC and GMP. These data were not confirmed in low transfusion burden (n:2) and non-transfused patients (n:26). In low/intermediate-1 MDS, a direct correlation between ferritin values and ROS levels in progenitors, but not in HSC, was detected. Interestingly, low/intermediate-1 risk patients that are no longer responding to recombinant human erythropoietin (rh-EPO) showed higher ROS levels in GMP and HSC. CONCLUSIONS: Our data showed that ROS can play a role in the pathogenesis and maintenance of low and intermediate-1 risk MDS clone; ROS status can be influenced by several clinical factors as ferritin levels and rh-EPO treatment. In this scenario, high ROS levels can contribute to genetic instability and influence progression to AML. Further biological studies are needed to elucidate ROS role in MDS pathogenesis and analyze the possible benefit of antioxidant drugs added to the standard MDS treatments

    High-dose sequential chemoradiotherapy in multiple myeloma: residual tumor cells are detectable in bone marrow and peripheral blood cell harvests and after autografting

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    Based on preliminary encouraging results in terms of response rate and survival, high-dose chemoradiotherapy has gained considerable interest in the treatment of patients with multiple myeloma (MM). We have evaluated the presence of residual myeloma cells in 15 of 18 patients enrolled in a high-dose sequential (HDS) chemoradiotherapy program followed by autografting. Our analysis has been performed both on bone marrow (BM) and peripheral blood (PB) cell harvests and after autografting. As it has been recently shown that B cells clonally related to malignant plasma cells are detectable in MM patients, we have developed a polymerase chain reaction (PCR)-based strategy to detect both residual B cells and plasma cells using clone-specific sequences derived from the rearrangement of Ig heavy chain (IgH) genes. The complementarity-determining regions (CDR) of IgH genes have been used to generate tumor-specific primers and probes. The constant (C) region usage defined the differentiation stage of residual myeloma cells. We report that plasma cells were detectable in PB and BM cell harvests and after transplantation in all assessable patients, irrespective of disease status. B cells were detectable in a consistent proportion of BM and PB samples at diagnosis, but only in one case at the time of PB and BM cell harvests. These cells became sometimes detectable after transplantation. Whether residual myeloma cells are clonogenic and contribute to relapse is currently unknown, and further investigations are required
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