1,721,130 research outputs found
Quantitative DNA proviral detection in HIV-1 patients treated with antiretroviral therapy
No full textThe amount of proviral DNA in peripheral blood mononuclear cells (PBMCs) from 93 HIV-1 seropositive patients on long-lasting antiretroviral therapy was measured by the SYBR green real-time PCR technique. Variable levels of proviral DNA, ranging from 14 to 1847 copies of HIV-1 DNA per 106 PBMC were found, without a significant correlation between proviral load and plasma HIV-1 RNA levels or CD4+ lymphocyte counts. To investigate the possible role of HIV-1 DNA levels as prognostic markers in clinical practice, the amount of proviral DNA and peripheral blood CD4+ lymphocyte counts were further evaluated after 5 months of continued therapy in 32 patients who maintained a persistently undetectable viremia throughout the observation period. Interestingly, a clear-cut decrease (≥0.5 log) in proviralDNAlevelswas significantly associated with a definite increase in CD4+ lymphocyte counts. Even though plasma HIV-1 RNA levels remain the basic parameter to monitor both the intensity of viral replication and the efficacy of therapeutic interventions, the results obtained in our study seem to indicate that measuring proviral DNA levels could represent an adjunct prognostic marker, especially useful in patients whose HIV-1 RNA levels drop below detectable limits
Discordant resistance interpretations in multi-treated HIV-1 patients.
No full textThe routine determination of drug resistance has become an important part of the clinical management of HIV-1 infected patients. Plasma samples from 130 individuals treated for at least 1 year with multiple NRTIs and NNRTIs were tested for the presence of mutations correlated to drug resistance. Since interpretation criteria represent a crucial point for virologists and clinicians, often complicated by the presence of novel and/or complex mutations patterns, we analyzed results interpreted by TruGene HIV-1 (Visible Genetics, Toronto, Ontario, Canada) and VirtualPhenotype (Virco, Mechelen, Belgium). A high degree of concordance was found for NNRTIs whereas NRTIs interpretation was highly discrepant. Since different approaches to monitoring resistance reflect different interpretation of results, the prediction of drugs resistance from a given HIV sequence might be contradictory and requires accurate standardization and unique interpretative rules
Meaning of DNA detection during the follow-up of HIV-1 infected patients: a brief review.
No full textA growing body of evidence indicates that proviral DNA load quantitation is an important parameter in establishing the dynamics of HIV infection. Proviral DNA load can be determined during the follow-up of infected individuals to evaluate reservoir status in addition to viral replication. Hence, the study of viral reservoirs, represented by HIV-1 latently infected cells, including resting memory CD4+ T cells, monocytes and macrophages, by which HIV-1 can be reactivated, opens new perspectives in the assessment and the comprehension of HIV-1 infection. However, the identification of viral reservoirs, that can store both wild and drug resistance viruses, is one of the most important steps in developing treatment strategies because it is now clear that viral reservoirs not only prevent sterilizing immunity but also represent a major obstacle to curing the infection with the potent antiretroviral drugs currently in use. Even if only careful evaluation of virological and immunological markers is necessary to fully characterize the course of HIV-1 infection and to provide a more complete laboratory-based assessment of disease progression, the availability of a new standardized assay such as DNA proviral load will be important to assess the true extent of virological suppression in treated patients and to verify the efficacy of new immune-based therapies aimed at purging HIV-1 DNA reservoirs. Several studies demonstrate, in fact, that HIV-1 cellular DNA load may be an indicator of spread of infection whereas the plasma RNA load is indicates active infection. This article will review the importance of monitoring HIV-1 proviral load DNA during the follow-up of HIV-1 infected subjects, suggesting that additional information complementing HIV RNA load could provide crucial information to monitor viral replication and the effectiveness of HAART therapy
HIV-1 tat protein and cell proliferation and survival: a brief review.
No full textMany studies have demonstrated that HIV-1 Tat plays a pivotal role both in the HIV-1 replication cycle and in the pathogenesis of HIV-1 infection. Indeed, Tat affects the HIV-1 replication cycle regulation increasing the proviral transcription rate several hundred-fold and acting on the elongation of viral transcripts. Moreover, Tat displays several important biological activities committed to uninfected and infected cells by a paracrine/autocrine mechanism due to secretion of Tat from infected cells. In particular, Tat modulates the expression of several cellular genes and triggers the activation of some signal transduction pathways and transcription factors suggesting a complex role in the scenario of HIV-1 infection. This review focuses on some aspects of Tat biological activity with particular regard to effects of Tat on cell proliferation and survival regulation
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
Cap. 4- IL MICROBIOMA OCULARE E IMPATTO SUL SISTEMA IMMUNE
No full textLa disfunzione delle ghiandole di Meibomio (Meibomian Gland Dysfunction - MGD) è la forma più comune di blefarite posteriore, ed è riconosciuta come la principale causa della malattia dell’occhio secco (Dry Eye Disease – DED) nella forma iperevaporativa. Ciò è riconducibile ad insufficienza in qualità e/o quantità del meibum secreto, che contribuisce ad un inadeguato film lipidico, responsabile di una eccessiva evaporazione del film lacrimale. L’attività di ricerca di anni recenti, unita alla crescente potenzialità delle tecniche analitiche, ha evidenziato come il microbiota locale giochi un ruolo fondamentale in questo complesso sistema. E’ sorprendente come la superficie oculare, seppure esposta alla contaminazione dell’ambiente esterno, contenga microorganismi commensali limitati in numero ed in grado di diversità. Questo aspetto fisiologico è assai peculiare nell’organismo: a differenza di altri siti biologici, come ad esempio la superficie della mucosa orale, la congiuntiva normale, i margini palpebrali e le lacrime contengono una varietà di specie assai inferiori
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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