1,720,958 research outputs found
Come prevenire e controllare la polmonite da Rhodococcus equi nel puledro in allevamenti a rischio d’infezione.
No full textNo evidence of Polyomavirus and EBV infections in Italian patients with mixed cryoglobulinemia infected chronically with HCV
No full textMixed cryoglobulinemia is a lymphoproliferative disorder associated with hepatitis C virus (HCV). In patients chronically affected by HCV the prevalence of mixed cryoglobulinemia is variable ranging from 0% to 56%. To verify whether polyomaviruses (PyV) play a role in this disorder a total of 222 blood samples from 63 HCV chronic patients, 43 with mixed cryoglobulinemia, 59 chronic lymphocytic leukemia, 50 polytransfused patients, and 50 blood donors were evaluated for Merkel (MCPyV), BKV, JCV, and SV40. EBV was additionally included in the analysis since association with this disorder has been reported. Mixed cryoglobulinemia patients infected chronically with HCV resulted negative for both PyV and EBV. MCPyV was found in 1 subject with Merkel Cell Carcinoma, in 10% of polytransfused and in 10% of blood donors while EBV was detected in 22% of polytransfused, 10% of B-cell lymphatic leukemia patients and 4% of blood donors (P < 0.01). Taken together, the absence of PyV and EBV in HCV-mixed cryoglobulinemia patients seems to exclude a direct involvement of these viruses in the pathogenesis of this disease while the presence of MCPyV in healthy individuals, at the same rate as in polytransfused patients, may reinforce data on a minimal role of this virus in other human pathologie
Merkel-cell polyomavirus and B-cell chronic lymphocytic leukemia
No full textIntroduction: Some authors described a possible association between CLL and Merkel cell polyomavirus (MCPyV) the pathogenetic agent of the Merkel-cell carcinoma, a rare and aggressive carcinoma of the skin. This association suggests the possibility that MCPyV may play a role in the pathogenesis of CLL as well as in the progression of the disease. Given several contradictory reports on the role of MCPyV in CLL, the presence of this virus as well of the other polyomaviruses JCV, BKV and of other lymphotropic viruses i.e. EBV and SV40 was investigated in highly purified malignant cells of a large number of CLL patients in different stages of the disease.
Methods: Blood samples were obtained from 66 patients fulfilling diagnostic criteria for CLL. In each case the IGHV gene mutational status was previously assessed using standard methods and CD38 and ZAP-70 expressions were determined by flow cytometry. Interphase FISH was performed on nuclei preparations of PBMC and each case was investigated for 13q deletion, 11q deletion, 17p deletion or presence of trisomy 12. The samples were processed immediately after blood withdrawl and processed by Ficoll-Hypaque density gradient resulting in purity of > 98% of CD19+/CD5+ CLL cells as assessed by expression analysis on flow cytometry. DNA was extracted by using a commercial and stored at -80 C° until the time of analysis. A multiple Q-PCR assay was run to amplify both Polyomavirus JCV, BKV and MCPyV. Real time Q-PCR for MCPyV Tag sequences, viral loads and the cellular beta-globin gene (as reference gene) were performed in each sample. Infection of EBV was evaluated by specific quantitative real time PCR (Q-PCR) assay using a commercially available molecular kit (Nanogen, Italy). The lowest limit of EBV detection assays was 100 copies/reaction and for Polyomavirus 10 copies/reaction. Q-PCR assays were run on the AB PRISM 7900 Sequence detection System (Applied Biosystems, Milan, Italy). Multiple negative controls (containing water instead of DNA templates), and positive controls (containing plasmid with the entire viral genome) were included with each assay batch.
Results: Among the 66 patients one case only (1.5%) was positive for MCPyV, while no one was positive for SV40, JCV and BKV. Five cases (7.6%) were positive for EBV replication in PBMC. The EBV positivity was independent from age, IGVH mutational status or from ZAP70 and CD38 expression or from the presence of 17p deletion, while correlates with previous treatments. The patient positive for MCPyV was affected by Merkel Cell skin carcinoma. This patient at diagnosis was negative for both MCPyV and EBV and underwent 4 therapy lines before positivity.
Conclusions: The low frequency of detection of MCPyV DNA in B-CLL patient samples, points against a direct involvement of MCPyV in CLL pathogenesis. Likely, the immune-depression of CLL, exacerbated by chemio- and immune-therapies, results in reactivation of both EBV and MCPyV
High expression of cytokines promoting angiogenesis and cell proliferation in early high-risk human papillomavirus infection
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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
In vivo detection of polyomaviruses JCV and SV40 in mesenchymal stem cells from human umbilical cords
No full textBACKGROUND:
Multipotent stromal cells are present in the Wharton's jelly matrix (WJSC) of the umbilical cord and can be used as an allogeneic source of cells to treat immunological disorders. Recently it was demonstrated that adult bone marrow (BM)-derived mesenchimal stromal cells (MSC) are susceptible to infection with viruses showing potential oncogenic properties, such as the polyomavirus JC (JCV). The aim of this study was to investigate the presence of human polyomaviruses (JCV, BK Virus-BKV, SV40, and Merkel cell polyomavirus-MCPyV) in WJSC, and explore the risk of infection.
PROCEDURE:
MSC samples from 35 umbilical cords were investigated by quantitative Real Time PCRs for the presence of DNA sequences of JCV, BKV, SV40, and MCPyV.
RESULTS:
JCV DNA was detected in 1/35 (2.8%) of MSC samples, while SV40 DNA was found in 3/35 (8.6%) of the examined samples. None of the samples showed sequences of BKV and MCPyV.
CONCLUSIONS:
The present study demonstrates the in vivo ability of polyomaviruses to infect WJSC. Since the therapeutic approach with the WJSC has high potentiality and a more intensive use can be easily hypothesized, the need to develop consensus guidelines to detect rare viral infections in MSC is pressin
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