1,720,990 research outputs found
Evaluation of the assay for hepatitis B virus (HBV) surface antigen quantification in the laboratory diagnosis of HBV infection
No full textEVALUATION OF THE ASSAY FOR HEPATITIS B VIRUS (HBV) SURFACE ANTIGEN QUANTIFICATION IN THE LABORATORY DIAGNOSIS OF HBV INFECTION
De Conto Flora, Fazzi Alessandra, Medici Maria Cristina, Arcangeletti Maria Cristina, Pinardi Federica, Ferraglia Francesca, Chezzi Carlo, Calderaro Adriana
Unit of Microbiology and Virology, Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy
Background: Hepatitis B virus infection is a global public health problem, affecting around 2 billion people worldwide. HBV infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The quantitative measurement of hepatitis B surface antigen (HBsAg) monitors the progress of chronic hepatitis B, and its rapid decline may be a predictor of the efficacy of antiviral therapy. Although the measurement of serum HBV DNA is the gold standard method for viral load evaluation, the assay is expensive and time consuming, while HBsAg quantification (qHBsAg) is rapid and cost-effective. The aim of this study is to compare the results of qHBsAg and HBV DNA determination, referred to subjects with chronic hepatitis B.
Material/methods: During the 2013-2015 period, 371 plasma or serum samples of subjects attending the University Hospital of Parma (Northern Italy) were subjected to qHBsAg, by means of the ARCHITECT HBsAg assay (Abbott, Wiesbaden, Germany), with a specificity and sensitivity of 99.87% and 99.52%, respectively, as reported by the manufacturer. Of these subjects, 333 (89,8%) were subjected to HBV DNA quantification, by means of the COBAS AmpliPrep/COBAS TaqMan HBV version 2.0 assay (Roche, Mannheim, Germany).
Results: Of the 371 individuals analysed, 224 (60.4%) were males (median age of 53 ± 15.3 years) and 147 (39.6%) females (median age of 52 ± 15.3 years); 235 (63.3%) were Italians and 136 (36.7%) foreigners. The subjects aged ≥61 years (30.7%) prevailed, and 359 (96.8%) were positive for qHBsAg. The comparison of the mean HBsAg level of the 359 positive subjects with those of different derived subpopulations evidenced higher HBsAg levels for HBeAg-positive subjects (3.1%; P<0.0001), subjects infected with genotype D of HBV (3.6%), and females (39%). Conversely, males (61%) and human immunodeficiency virus type 1 (HIV 1) co-infected subjects (3.6%) showed lower HBsAg levels. Moreover, HBsAg levels decreased with age, with significant differences for subjects aged ≤30 (P<0.0001) and ≥51 (P<0.05) years. The accordance among the results of qHBsAg and HBV DNA determination was of 69.7% (232/333 samples) and the qHBsAg assay sensitivity of 99.6% (227/228 samples).
Conclusion: This study assesses that many factors may influence HBsAg levels, such as sex, age, HIV co-infection, HBeAg status, and HBV genotype. Although the sensitivity of qHBsAg assay is high, the discrete accordance with HBV DNA determination envisages that HBsAg measurement cannot be a reliable substitute, but a complementary assay, which allows better chronic HBV infection monitoring
Confronto tra strumenti VIDAS e LIAISON nel saggio sierologico per la diagnosi di infezione da virus Epstein–Barr.
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Temporal dynamics of hepatitis C genotypes in a five-year hospital-based surveillance in Northern Italy
No full textHepatitis C virus (HCV) genotypes have became important epidemiological markers in the management of HCV-infected subjects and infection treatment. The dynamics of HCV genotypes are changing in Europe. During a five-year (2009-2013) hospital-based surveillance in the area of Parma, Northern Italy, serum/plasma samples from 1,265 HCV RNA-positive subjects were genotyped. Subtypes 1b, 3a, and 1a were predominant (32.6 %, 19.1 %, and 17.8 %, respectively), with a correlation between viral load and gender. Subtypes 1a and 3a were more frequent in adults and males with a significant difference with the over-50 age group and females (P > 0.0001). Subtype 1b, as well as 2a/2c and G2 not-subtypeable (15.7 % and 7.2 %, respectively), were more common in females and in the over-50 age group compared to males (P < 0.0001, P < 0.0001, and P < 0.05, respectively) and the under-50 age group (P < 0.0001). While subtype 1b showed a nearly constant trend, subtype 1a peaked in 2012, when a consistent decrease in G2 was observed. The increasing detection of G4, mainly in adults, and subtypes 1a and 3a suggests their epidemiological relevance in the population. The detection of more than one HCV genotype in the same sample (0.2 %) and different genotypes in distant samples (5.1 %) from the same subject reinforces the opinion that re-infection and super-infection with different genotypes are not negligible events, especially in HIV-infected subjects. The dynamics of HCV genotypes could have significant implications for infection control
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
Multicentric Evaluation of New Commercial Enzyme Immunoassays for the Detection of Immunoglobulin M and Total Antibodies against Hepatitis A Virus.
No full textA multicentric clinical study was conducted on representative sera from 1,738 European and U.S. subjects for the evaluation of new anti-hepatitis A virus enzyme immunoassays from Bio-Rad Laboratories. Comparison with reference DiaSorin S.p.A. tests confirmed the good performance of Bio-Rad assays (99.85% and 99.47% overall agreement in detecting total antibodies and IgM, respectively)
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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