1,720,976 research outputs found
Polymorphisms of the four BKV subtypes and their influence on viral in vitro growth efficiency : a comparative study
No full textSUMMARY Four different genomic subtypes of the ubiquitous human polyomavirus BKV have been identified. The existence of the BKV genomic subtypes is due to nucleotide polymorphisms clustered within the nucleotide sequence 1744-1812 of the major capsid protein VP1. These polymorphisms cause amino acid substitutions within the VP1 61-83 amino acidic region, which corresponds to the BC loop of SV40 and may play an important role in virus binding and entry to its host cell. To determine whether the polymorphisms of this VP1 region may affect the in vitro growth ability of the virus, we created recombinant viral genomes harboring the polymorphisms characteristic of the four viral subtypes within the same genomic background. We then performed in vitro infections and compared the growth efficiency of the four viral strains at different time points during the infection course. The results of our study indicated that the viral strains containing the nucleotide polymorphisms of subtypes I and II exhibited the highest replication ability in Vero cells and the same replication pattern. Subtype IV exhibited a lower growth efficiency, while the replication ability of subtype III was markedly reduced compare to that of the other subtypes. The results of our study showed that, as well as for the other polyomaviruses, the BC loop of BKV plays a crucial role in the virus lifecycle, as suggested by the fact that amino acid substitutions clustered within the VP1 61-83 region may profoundly affect the in vitro growth efficiency of the virus. The identification of amino acid residues that are critical for virus growth and viability might be useful to support, in the future, the development of new clinical tools for the treatment of BKV- associated diseases
Ipotesi eziologiche ancora attuali nel campo dei disturbi mentali = Current hypothesis on the etiology of mental disorders
No full textIntroduction: Schizophrenia and related psychiatric disorders are diseases with unknown origin. Family and adoption studies indicate a strong genetic component of disease susceptibility. However, epidemiological studies also point to a role for infections and other environmental factors in the etiology of this complex disease. In particular, many studies support the hypothesis that the exposure to infective agents, such as bacteria and viruses, may be a risk factor for the development of mental disorders. Materials and methods: In this brief review we will at first describe the viral agents that can be directly, and by different means, associated with mental illness. Then, the scientific literature which has focused on the association between schizophrenia and the most relevant etiopathogentic hypothesis will be analyzed and discussed. Conclusions: All data analyzed suggest the presence of elements in favor of the involvement of viruses in the pathogenesis of some mental diseases. However, there are no definitive data and it will be necessary to define multicenter research projects, in order to verify, by means of advanced technologies, these interesting theories
Infezioni virali congenite perinatali e neonatali
No full textViral infections may be vertically transmitted from mother to child at different times, ranging from in utero transmission, which occurs during pregnancy, perinatal transmission, which takes place during delivery and postnatal transmission, which is usually the consequence of breastfeeding. Mother-to-child transmission, which may occur after primary, recurrent or chronic maternal infection, is potentially harmful to the fetus or the newborn since it may result in miscarriage, fetal death, congenital anomalies, intrauterine growth restriction, or severe neonatal disease. Some risk factors are thought to affect the rate of mother-to-child transmission, such as the presence of other viral infections, maternal viral load, type of infection (primary versus recurrent), obstetrical procedures (prolonged rupture of membranes, mode of delivery), social-economical conditions and breastfeeding. For some of the vertically transmitted viruses, interventions are nowadays available to prevent mother-to-child transmission, such as vaccines, passive immunization, antiviral drugs. Moreover, perinatal and postnatal infections may be prevented by the use of elective caesarean delivery and avoidance of breastfeeding
Application of molecular tools for the diagnosis of central nervous system infections
No full textMany infectious agents can cause central nervous system (CNS) diseases in humans. Since microbial agents infecting CNS are numerous and have different features, conventional laboratory tests may not be sensitive enough to identify and characterise viruses and bacteria in human biological specimens. Thus, the need to define methods for the diagnosis of infectious neurological diseases, such as progressive multifocal leukoencephalopathy (PML), is urgent, in order to improve the outcome of the diseases with rapid and accurate detection of the pathogens
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
Analisi longitudinale della sintomatologia post-traumatica su 61 genitori di bambini malati di leucemia dalla diagnosi allo stop terapia
No full textThe study was aimed at investigating the possible presence of post-traumatic symptomatology in parents of children with leukaemia, during the period from the diagnosis to the stop therapy (two years later) with particular attention to this stage so far little explored.
A longitudinal study with 4 time points, corresponding with important stages of the therapeutic protocol, was realized using a self-report questionnaire (PTSD Symptom Inventory) with 61 parents of leukemic children, contacted at the Department of Paediatrics, Oncology Hemathology Division, University Hospital of Padova. The findings show the presence in these parents of a moderate level of symptomatology at the diagnostic moment and a persistent level of symptomatology during all the time points considered
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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