Search results for "viruses"
showing 10 items of 1182 documents
Genome organization and nucleotide sequence of human papillomavirus type 39
1991
The 7833-bp nucleotide sequence of human papillomavirus type 39 (HPV39), which is associated with genital intraepithelial neoplasias and invasive carcinomas, has been determined. The genome organization deduced from the sequence shares characteristic features with other genital papillomaviruses. According to sequence comparisons, HPV39 most closely resembles HPV18 and may be a member of a subgroup of genital papillomaviruses distinct from the HPV16/31/33 group. As a novel feature, we report a 1.3-kb open reading frame on the DNA strand which lacks major open reading frames in the other sequenced HPV genomes.
Network dynamics of eukaryotic LTR retroelements beyond phylogenetic trees
2009
Abstract Background Sequencing projects have allowed diverse retroviruses and LTR retrotransposons from different eukaryotic organisms to be characterized. It is known that retroviruses and other retro-transcribing viruses evolve from LTR retrotransposons and that this whole system clusters into five families: Ty3/Gypsy, Retroviridae, Ty1/Copia, Bel/Pao and Caulimoviridae. Phylogenetic analyses usually show that these split into multiple distinct lineages but what is yet to be understood is how deep evolution occurred in this system. Results We combined phylogenetic and graph analyses to investigate the history of LTR retroelements both as a tree and as a network. We used 268 non-redundant …
Genetic Diversity and Evolution of Viral Populations
2021
Abstract Population genetic diversity plays a prominent role in viral evolution, pathogenesis, immune escape, and drug resistance. Different mechanisms are responsible for creating and maintaining genetic diversity in viruses, including error-prone replication, repair avoidance, and genome editing, among others. This diversity is subsequently modulated by natural selection and random genetic drift, whose action in turn depends on multiple factors including viral genetic architecture, viral demography, and ecology. Understanding these processes should contribute to the development of more efficient control and treatment strategies against viral pathogens.
Baculoviral display of functional scFv and synthetic IgG-binding domains.
2000
Viral vectors displaying specific ligand binding moities such as scFv fragments or intact antibodies hold promise for the development of targeted gene therapy vectors. In this report we describe baculoviral vectors displaying either functional scFv fragments or the synthetic Z/ZZ IgG binding domain derived from protein A. Display on the baculovirus surface was achieved via fusion of the scFv fragment or Z/ZZ domain to the N-terminus of gp64, the major envelope protein of the Autographa californica nuclear polyhedrosis virus, AcNPV. As examples of scFv fragments we have used a murine scFv specific for the hapten 2-phenyloxazolone and a human scFv specific for carcinoembryonic antigen. In pri…
Fatal neuroinvasion and SARS-CoV-2 tropism in K18-hACE2 mice is partially independent on hACE2 expression
2022
ABSTRACTAnimal models recapitulating distinctive features of severe COVID-19 are critical to enhance our understanding of SARS-CoV-2 pathogenesis. Transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) under the cytokeratin 18 promoter (K18-hACE2) represent a lethal model of SARS-CoV-2 infection. The precise mechanisms of lethality in this mouse model remain unclear. Here, we evaluated the spatiotemporal dynamics of SARS-CoV-2 infection for up to 14 days post-infection. Despite infection and moderate pneumonia, rapid clinical decline or death of mice was invariably associated with viral neuroinvasion and direct neuronal injury (including brain and spinal neurons). Neuroinv…
Immune characterization of the HBHA-specific response in Mycobacterium tuberculosis-infected patients with or without HIV infection.
2017
Introduction RD1-based Interferon-γ Release Assays (IGRAs) cannot distinguish latent from active tuberculosis (TB) disease. Conversely, a positive response to heparin-binding haemagglutinin (HBHA)-based IGRAs, among TB-infected subjects, correlates with Mycobacterium tuberculosis (Mtb) containment and low risk of TB progression. The aim of this study was to characterize HBHA-immune responses in HIV-infected and uninfected subjects with active TB or latent TB infection (LTBI). Methods 49 subjects were prospectively enrolled: 22 HIV-uninfected (13 TB, 9 LTBI) and 27 HIV-infected (12 HIV-TB, 15 HIV-LTBI). Whole blood and peripheral blood mononuclear cells were stimulated with HBHA and RD1 anti…
Sex difference in the interaction of alcohol intake, hepatitis B virus, and hepatitis C virus on the risk of cirrhosis
2017
Background The joint effect of the interaction of alcohol intake, hepatitis B virus (HBV) and hepatitis C virus (HCV) on the risk of cirrhosis is still unexplored because a large sample size is required for this investigation. Objective Evaluation of interaction of HBV, HCV and alcohol abuse on the risk of cirrhosis. Design We analysed 12,262 consecutive patients with chronic liver disease of various aetiologies referring to 95 Italian liver units in 2001 or 2014. To evaluate the interaction between alcohol abuse, HBV infection, and HCV infection, patients unexposed to either factors were used as reference category. Adjustment for BMI and age was done by multiple logistic regression analysi…
Impact of Safety-Related Dose Reductions or Discontinuations on Sustained Virologic Response in HCV-Infected Patients: Results from the GUARD-C Cohor…
2015
Background: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. Methods: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the i…
Factors associated with first- versus second-generation long-acting antipsychotics prescribed under ordinary clinical practice in Italy
2018
Background For many years, long-acting intramuscular (LAI) antipsychotics have been prescribed predominantly to chronic and severe patients, as a last resort when other treatments failed. Recently, a broader and earlier use of LAIs, particularly second-generation LAIs, has been emphasized. To date, few studies attempted to frame how this change in prescribing took place in real-world practice. Therefore, this study aimed to describe the clinical features of patients prescribed with LAIs, and to explore possible prescribing differences between first- and second-generations LAIs under ordinary clinical practice in Italy. Methods The STAR Network "Depot" Study is an observational, longitudinal…
Biomedical implications of viral mutation and evolution
2012
Mutation rates vary hugely across viruses and strongly determine their evolution. In addition, viral mutation and evolution are biomedically relevant because they can determine pathogenesis, vaccine efficacy and antiviral resistance. We review experimental methods for estimating viral mutation rates and how these estimates vary across viral groups, paying special attention to the more general trends. Recent advances positing a direct association between viral mutation rates and virulence, or the use of high-fidelity variants as attenuated vaccines, are also discussed. Finally, we review the implications of viral mutation and evolution for the design of rational antiviral therapies and for e…