1,721,144 research outputs found
CARATTERIZZAZIONE DELL'INFEZIONE DA VIRUS DELL'EPATITE B (HBV) IN UNA COORTE DI SOGGETTI HIV-POSITIVI IN MALAWI
Full text linkBackground. This study aimed at evaluating both HBV and occult HBV infection prevalence in a cohort of HIV-positive women receiving HAART.
Methods. This retrospective laboratory-based study was performed on 1,006 plasma samples collected from women (median age:31 years; range:15-70 years) referred to DREAM centers in Malawi. Anti-HBc, anti-HBs and HBsAg markers were detected by commercial enzyme-immunoassays (Abbott/Murex). Samples resulted with an “anti-HBc-alone” serological profile were assessed by quantitative branched-HBV-DNA assay (SiemensDiagnostics). Samples under lower detection limit (<2,000 copies/ml) were tested by a semi-quantitative in-house PCR (lower detection limit: 350 copies/ml).
Results. Overall, 56.3% samples were anti-HBc+. Of them 56.7% were anti-HBs+. The remaining 43.3% anti-HBs- samples were tested for HBsAg. 8.3% (83/1,006) of patients had an HBV chronic carrier serological profile.
Of the 158 samples resulted with an “anti-HBc-alone” serological profile and tested by branched-DNA assay and/or in-house PCR , 85.8% was HBV-viremic. 12.8% (17/133) showed a plasmatic HBV-DNA viral load >104 copies/ml. 87.2% (117/134) of HBV-DNA-positive samples showed HBV-DNA plasma levels ≤104 copies/ml. The frequency of occult HBV infection among patients with an “anti-HBc-alone” serological profile was 75% (116/155).
Conclusions. The prevalence of HBsAg-carriers in the study cohort was 8.3%, confirming Malawi as a high HBV endemic area. Detection of plasmatic HBV-DNA enabled to define an occult HBV infection in 75% of patients with an “anti-HBc-alone” serological status. This evidence underlines the need of introducing the use of HBV-DNA molecular assays as a diagnostic tool in African settings
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
Sleep is differently modulated by basal forebrain GABA(A) and GABA(B) receptors
No full textThere is evidence that GABA plays a major role in sleep regulation. GABA(A) receptor agonists and different compounds interacting with the GABA(A) receptor complex, such as barbiturates and benzodiazepines, can interfere with the sleep/wake cycle. On the other hand, there is very little information about the possible role of GABA(B) receptors in sleep modulation. The nucleus basalis of Meynert (NBM), a cholinergic area in the basal forebrain, plays a pivotal role in the modulation of sleep and wakefulness, and both GABA(A) and GABA(B) receptors have been described within the NBM. This study used unilateral infusions in the NBM to determine the effects of 3-hydroxy-5-aminomethylisoxazole hydrobromide (muscimol hydrobromide, a GABA(A) receptor subtype agonist) and beta-(aminomethyl)-4-chlorobenzenepropanoic acid (baclofen, a GABA(B) receptor subtype agonist) on sleep parameters in freely moving rats by means of polygraphic recordings. Muscimol (0.5 nmol) and baclofen (0.7 nmol) induced an increase in slow-wave sleep and an inhibition of wakefulness. Muscimol, but not baclofen, also caused a decrease in desynchronized sleep parameters. The results reported here indicate that 1) the NBM activation of both GABA(A) and GABA(B) receptors influences the sleep/wake cycle, and 2) GABA(A) but not GABA(B) receptors are important for desynchronized sleep modulation, suggesting that the two GABAergic receptors play different roles in sleep modulation
Stimulation of NMDA and AMPA receptors in the rat nucleus basalis of Meynert affects sleep
No full textThe nucleus basalis of Meynert (NBM), a heterogeneous area in the basal forebrain involved in the modulation of sleep and wakefulness, is rich in glutamate receptors, and glutamatergic fibers represent an important part of the input to this nucleus. With the use of unilateral infusions in the NBM, the effects of two different glutamatergic subtype agonists, namely N-methyl-D-aspartic acid (NMDA and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) hydrobromide, on sleep and wakefulness parameters were def;ermined in fi eely moving rats by means of polygraphic recordings. NMDA (5 nmol) and AMPA (0.4 nmol) induced an increase in wakefulness and an inhibition of slow-wave sleep. AMPA, but not NMDA, also caused a decrease in desynchronized sleep. These AMPA- and NMDA-mediated effects were counteracted by a pretreatment with the specific NMDA antagonist 2-amino-5-phosphonopentanoic acid (20 nmol) and the specific AMPA antagonist 6,7-dinitroquinoxaline-2,3-dione (2 nmol), respectively. The results reported here indicate that 1) the NBM activation of both NMDA and AMPA glutamate receptors exert a modulatory influence on sleep and wakefulness, and 2) AMPA, but not NMDA receptors, are involved in the modulation of desynchronized sleep, suggesting a different role for NBM NMDA and non-NMDA receptors in sleep modulation
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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