P Simmonds

..Large population sizes and intense selection pressures that optimize fitness may be additional factors that set virus evolution apart from that of their hosts...

..These findings potentially reconcile the rapid evolution of RNA viruses over short periods with the documented examples of extreme conservatism evident from their intimate coevolution with their hosts...

..abstract:..

..These R5 envelopes conferred a wide range of macrophage tropism and included highly macrophage-tropic variants from brain and non-macrophage-tropic variants from lymph node...

..This study provides comprehensive bioinformatic resources for future functional studies of MNV and other caliciviruses...

..In conclusion, these proposals provide the framework by which the HCV databases store and provide access to data on HCV, which will internationally coordinate the assignment of new genotypes and subtypes in the future...

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..Predominantly parenteral routes of transmission were demonstrated by infection restricted to injection drug users and persons with hemophilia and absence of infection in homosexual men with AIDS and low-risk controls...

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..These contrasting aspects of conservatism and adaptability provide a fascinating paradigm in which to explore the complex selection pressures that underlie the evolution of HCV and other persistent viruses...

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..Overall, this study identifies common themes in the diversification process generating picornavirus serotypes that contribute to understanding of their evolution and pathogenicity...

..Classification by phylogenetic relatedness rules out simple sequence similarity measurements as a method for assigning HCV genotypes, but provides a more appropriate description of the evolutionary and epidemiological history of a virus...

..Establishing a framework for PCR-based screening would also enable the testing for others such as hepatitis A virus, parvovirus B19 and GBV-C/HGV for which serological detection methods cannot be or have not been developed...

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..Large population sizes and intense selection pressures that optimize fitness may be the factors that set virus evolution apart from that of their hosts...

..quot; This places a major restriction on the use of nucleotide or amino acid sequence comparisons to calculate times of divergence of other viruses evolving under the same structural constraints as GB viruses...

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..The study demonstrates the extraordinary genetic diversity of HRVs, their rapid population turnover, and their extensive involvement in childhood respiratory disease...

..Future investigation of the epidemiological and biological opportunities and constraints on intertypic recombination will provide more information about its influence on the longer term evolution and pathogenicity of parechoviruses...

..Destruction of cells destined to become CD8+ lymphocytes may be a major factor in the decline in CD8+ lymphocyte frequencies and function on disease progression and may contribute directly to the observed immunodeficiency in AIDS...

..The relatively low level of amino acid sequence variation observed between these geographically and phylogenetically defined groups of variants suggests that they are unlikely to display significant biological differences...

..Estimation of the time of origin of the major HCV genotypes (types 1-6) is problematic, but our data and analogy with other viruses suggest that divergence occurred at least 500-2000 years ago...

..The possibility that recombination contributed to their subsequent spread through improved fitness requires further biological and immunological characterization...

..Other sites of variation suggest minor modifications to this model and have implications for the probable functions of the 5'NCR...

..This study provides the basis for future investigation of possible phenotypic similarities that underline the shared distributions of HIV variants infecting microglia and tissue macrophages outside the CNS...

..Serotype identification is currently problematic following the widespread adoption of polymerase chain reaction (PCR)-based methods for HEV detection in place of virus culture...

..These new findings have a number of implication for understanding the origins and epidemiology of HBV infection in non-human primates...

..Neurological complications in AIDS occur when this control breaks down, due to systemic immunosuppression from HIV that destroys CD8 lymphocyte function and/or through the evolution of more aggressive neuropathogenic variants...

..CONCLUSION: We have developed a highly sensitive multiplexed PCR for HIV-1 and HCV RNA screening that can be introduced into current PCR-based blood donor screening at minimal cost and without significant operational changes...

..The geographical distribution of virus variants is consistent with a long evolutionary history that may parallel that of pre-historic human migrations, implying that the long-term evolution of this RNA virus is extremely slow...

..The prediction of similar structures in the same region of hepatitis C virus may allow the functions of these structures to be determined with a more tractable experimental model...

..These findings suggest that neocortical productive HIV infection is a significant factor in AIDS-related dementia, although this may reflect merely a higher overall viral burden in the brain...

..We conclude that there is a surprising degree of ongoing neuroinflammation in HAART-treated patients, particularly in the hippocampus. This may pose a threat for the future health of individuals maintained long-term on HAART therapy...

..The extensive sequence data from multiple genome regions of HRV-C and analyses of recombination in the current study will assist future formulation of consensus criteria for HRV-C type assignment and identification...

..These findings support the hypothesis for the co-evolution of TTV-like viruses with their hosts over the period of primate speciation, potentially analogous to the evolution of primate herpesviruses...

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..We determined the relative importance of these viruses and the specific HPeV types involved in the development of central nervous system-associated disease...

..Bioinformatic and physical characterization methods both identified fundamental differences in the configurations of viral genomic RNA that may modify their interactions with host cell defenses and their ability to persist...

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..This study provides an indication of the extreme sequence diversity of TTV, a characteristic which is untypical of parvoviruses...

..We investigated the frequencies of persistence, tissue distribution, and influence of immunosuppression on replication of these viruses...

..This study provides the first evidence for widespread circulation of parvoviruses in primates and enables future investigations of their epidemiology, host specificity, and (co)evolutionary histories...

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..The system will allow future comprehensive phenotypic characterization of naturally occurring and treatment-induced mutations for PIs in trial or entering clinical use...

..These results are relevant for the molecular epidemiology of HIV-1 in Africa and for the design of a future vaccine against HIV-1 in this region...

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..Hot-spot viRNAs were found to be significantly less efficient at mediating antiviral RNAi than cold-spot viRNAs, pointing toward a nucleic acid-based viral decoy mechanism to evade the RNAi response...

..HRV-C's disease associations, its prevalence and evidence for interfering effects on other respiratory viruses mandates incorporation of rhinoviruses into future diagnostic virology screening...

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..Human metapneumovirus (HMPV) is a recently discovered human paramyxovirus associated with a spectrum of respiratory symptoms from the common cold to pneumonia and bronchiolitis...

..To investigate the potential for CD4+CD8+ T cells [CD8 double positive (CD8 DP)] T cells to form a reservoir of HIV-1 following HAART through measurement of the rate of decay of infected CD4/CD8 DP T cells...

..The cause of HIV associated dementia and cognitive disability remains poorly understood. Perhaps most significantly, the long-term consequences of clinically occult brain infection are unknown and will require further investigation...

..The high level of infection of CD8bright CD4dim lymphocytes could have a direct role in the decline in CD8 lymphocyte function that accompanies HIV disease progression...

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..Collections of clinically well-characterized HIV-infected tissues such as those in the Edinburgh Brain Bank are a vital resource to support ongoing studies of viral pathogenesis in the CNS and interactions with drug abuse...

..The degree of city-specific segregation of HCV subtype 1a sequences was linearly related to that of subtype 3a, indicating that these subtypes have spread through similar transmission networks...

..Such recombinant products have extended the safety profile of their predecessors by ensuring that all reagents used for cell culture, purification steps, and stabilisation and storage buffers are completely independent of human plasma...

..To investigate their potential role in respiratory disease, we determined their frequencies of detection, clinical presentations and epidemiological characteristics among samples referred for diagnostic respiratory virus testing...

..The frequency of transmission and clinical outcome after exposure to enterovirus-contaminated blood components in recipients is unknown...

..To investigate the infectivity for hepatitis C virus (HCV) of intravenous anti-D immunoglobulin batches manufactured in Ireland between 1991 and 1994...

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..Determining what epidemiological or biological factors led to such a complete and geographically extensive population replacement over this short period is central to further understanding the nature of parvovirus evolution...

..The implications for drug-using patients who survive long term with HIV/AIDS are discussed, particularly in relation to premature neurodegeneration...

..The additional impact of intravenous drug abuse on HIV-associated brain disease, then and now, is also reviewed. Predictions for the future are discussed, based on what is known at present and on recently emerging data...

..High detection frequencies (10%) and viral loads in stool samples provide evidence for enteric replication of HRV, and its association with enteric disease requires further etiological studies...

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..However, the number of GFAP-positive astrocytes was neither increased in pre-AIDS nor in drug abuse, in contrast with microglia which we have shown previously to be up-regulated in both states...

..These findings denote a recent expansion from Africa. We compare the phylogenetic relationships of HML-2 sequences that are unique to humans and consider whether these elements have played a role in the remodeling of the hominid genome...

..Within the age groups studied these significant neuropathological changes remained subclinical and were not yet associated with cognitive impairment...

..By this means, we will learn much more about the clinical relevance of HPeVs and the association of different HPeV types with specific disease presentations...

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..For each cell type, blocking assays with an anti-CD4 monoclonal antibody indicated that entry was CD4-dependent...

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..In this review, we will describe both the disease associations and underlying epidemiological and/or biological basis for the often marked differences in disease outcomes between HPeV types...

..In this study, we investigated whether the recently discovered WU and KI polyomaviruses (WUPyV and KIPyV) and Merkel cell polyomavirus (MCPyV) could, like BKV and JCV, persist, mutate, and reactivate in immunodeficient subjects...

..In conclusion, HCV exchange between European IDU populations has occurred on a large scale, and, overall, country-specific clustering for HCV was less than that shown for HIV...

..The extensive variation in R5 tropism reported here is likely to have an important impact on pathogenesis and on the capacity of HIV-1 to transmit...

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..The results provide a baseline for prediction of the future course of the HCV epidemic, and its likely response to transmission control policies...

..Reference sequences for accurate HCV genotyping are required for optimized treatment, and a better knowledge of the global viral sequence diversity is needed to guide vaccines or new drugs effective in the world wide epidemic...

..Alternatively, if the long-range interactions were mutually exclusive, the SL9266 CRE may function as a molecular switch controlling a critical aspect of HCV genome replication...

..0 specimen results were within 1 log, as were 85.6% (237/277) of paired Roche Monitor 2.0 and Bayer specimen results. These data demonstrate that the LCx assay may be used for quantitation of HCV RNA in HCV-infected individuals...

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..When scanning the entire genomes of HCV and polio virus for structure elements, RNA-DECODER's results indicate a markedly higher specificity than MFOLD, PFOLD and RNAALIFOLD...

..These envelopes are able to infect cells that express low levels of CD4 and/or CCR5 and may have adapted for replication in brain macrophages and microglia, which are known to express limited amounts of CD4...

..The primary aim of the POSH study is to establish whether genetic status influences the prognosis of primary breast cancer independently of known prognostic factors...

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..CONCLUSION: Of susceptible patients, 64 percent became infected with HGV/GVC-C when transfused with RNA-positive blood components. E2Ab-positive patients were protected against HGV/GBV-C infection...

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