1,720,972 research outputs found
Evaluation of Xpert MTB/RIF Ultra assay for rapid diagnosis of pulmonary and extra-pulmonary tuberculosis in an Italian center
Full text linkAbstract not availabl
Impact of immigration on tuberculosis in a low-incidence area of Italy: a molecular epidemiology approach
No full textP>The effects that immigration might have on the epidemiology of tuberculosis (TB) in a low-incidence area of Italy was investigated by determining, in autochthonous and immigrant TB patients, the molecular characteristics of the Mycobacterium tuberculosis complex (MTBC) isolates, which may provide information on their phylogeographical origin. A total of 1080 MTBC strains, collected during a 4-year period in Tuscany from 614 Italian-born and 466 foreign-born patients, were genotyped by spoligotyping and assigned to the different phylogeographical lineages that constitute the MTBC. The autochthonous Euro-American phylogeographical lineage, which includes the spoligotype families T, Haarlem, Latin American-Mediterranean (LAM), S and X, was highly prevalent among Italian-born patients, with a total of 477 cases (77.7%), and foreign-born TB patients, with a total of 270 cases (57.9%); 24 Italian-born (3.9%) and 141 foreign-born (30.3%) TB cases were due to MTBC genotypic families associated with distant geographical areas, i.e. East African-Indian (EAI), Beijing, Central Asian (CAS), and Mycobacterium africanum. Strains of Mycobacterium bovis and strains of undefined genotype, which are all considered together, as it is not possible to assign a specific geographical origin, accounted for 113 (18.4%) Italian cases and 55 (11.8%) foreign-born cases. A total of 79 Italian TB cases (12.9%) have been attributed to transmission from immigrants to the local population. No significant contribution to drug resistance appeared to be associated with imported MTBC strains. It is concluded that, at present, the overall impact of imported TB on public health in the low-incidence study area is relatively modest and of the same order as in other western countries
Genotyping and clarithromycin susceptibility testing of Mycobacterium avium subsp. hominissuis isolated in Tuscany, Italy
Full text linkMycobacterium avium subsp. hominissuis (MAH) is a major cause of nontuberculous mycobacteria infection and
the incidence of MAH infections is increasing in many countries. This study aimed at determining the VNTRbased
genetic diversity and the susceptibility to clarithromycin of a collection of 71 MAH human strains isolated
in the last seven years. The VNTR analysis, revealing 16 unique patterns and 8 clusters including a total of 55
isolates, showed that most MAH isolates displayed a close genetic relationship, indicating that the MAH genotypes
are quite homogeneous in our geographical area. Clarithromycin showed strong antimicrobial activity
against MAH isolates, as indicated by the high proportion (94.4%) of susceptible strains. No association between
specific VNTR patterns and the clinical features or the MIC of clarithromycin was found
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
Virulence of Mycobacterium avium Subsp. hominissuis Human Isolates in an in vitro Macrophage Infection Model
Full text linkBackground: Mycobacterium avium subsp. hominissuis (MAH) is an environmental opportunistic pathogen for humans and swine worldwide; in humans, the vast majority of MAH infections is due to strains belonging to specific genotypes, such as the internal transcribed spacer (ITS)-sequevars Mav-A and Mav-B that mostly cause pulmonary infections in elderly patients and severe disseminated infections in acquired immunodeficiency syndrome patients, respectively. To test whether the different types of infections in distinct patients' populations might reflect a different virulence of the infecting genotypes, MAH human isolates, genotyped by ITS sequencing and MIRU-VNTR minisatellite analysis, were studied for the capacity to infect and replicate in human macrophages in vitro. Methods: Cultures of human peripheral blood mononuclear cells and phagocytic human leukemic cell line THP-1 cells were infected with each MAH isolate and intracellular colony-forming units (CFU) were determined. Results: At 2 h after infection, i.e., immediately after cell entry, the numbers of intracellular bacteria did not differ between Mav-A and Mav-B organisms in both phagocytic cell types. At 5 days, Mav-A organisms, sharing highly related VNTR-MIRU genotypes, yielded numbers of intracellular CFUs significantly higher than Mav-B organisms in both phagocytic cell types. MIRU-VNTR-based minimum spanning tree analysis of the MAH isolates showed a divergent phylogenetic pathway of Mav-A and Mav-B organisms. Conclusion: Mav-A and Mav-B sequevars might have evolved different pathogenetic properties that might account for their association with different human infections
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
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