bluuebunny/crossref_metadata_2025_split huggingface dataset:
Moloney Murine Leukemia Virus Integrase Protein Augments Viral DNA Synthesis in Infected Cells
Authors: Lai Lilin , Liu Hongmei , Wu Xiaoyun , Kappes John C. 
Published: July 2002

ABSTRACT

Mutations in the
IN
domain of retroviral DNA may affect multiple steps of the virus life cycle, suggesting that the IN protein may have other functions in addition to its integration function. We previously reported that the human immunodeficiency virus type 1 IN protein is required for efficient viral DNA synthesis and that this function requires specific interaction with other viral components but not enzyme (integration) activity. In this report, we characterized the structure and function of the Moloney murine leukemia virus (MLV) IN protein in viral DNA synthesis. Using an MLV vector containing green fluorescent protein as a sensitive reporter for virus infection, we found that mutations in either the catalytic triad (D184A) or the HHCC motif (H61A) reduced infectivity by approximately 1,000-fold. Mutations that deleted the entire IN (ΔIN) or 34 C-terminal amino acid residues (Δ34) were more severely defective, with infectivity levels consistently reduced by 10,000-fold. Immunoblot analysis indicated that these mutants were similar to wild-type MLV with respect to virion production and proteolytic processing of the Gag and Pol precursor proteins. Using semiquantitative PCR to analyze viral cDNA synthesis in infected cells, we found the Δ34 and ΔIN mutants to be markedly impaired while the D184A and H61A mutants synthesized cDNA at levels similar to the wild type. The DNA synthesis defect was rescued by complementing the Δ34 and ΔIN mutants in
trans
with either wild-type IN or the D184A mutant IN, provided as a Gag-IN fusion protein. However, the DNA synthesis defect of ΔIN mutant virions could not be complemented with the Δ34 IN mutant. Taken together, these analyses strongly suggested that the MLV IN protein itself is required for efficient viral DNA synthesis and that this function may be conserved among other retroviruses.
Antigenicity and Immunogenicity of Novel Chimeric Hepatitis B Surface Antigen Particles with Exposed Hepatitis C Virus Epitopes
Authors: Netter Hans J. , Macnaughton Thomas B. , Woo Wai-Ping , Tindle Robert , Gowans Eric J. 
Published: July 2002

ABSTRACTThe small envelope protein of hepatitis B virus (HBsAg-S) can self-assemble into highly organized virus like particles (VLPs) and induce an effective immune response. In this study, a restriction enzyme site was engineered into the cDNA of HBsAg-S at a position corresponding to the exposed site within the hydrophilic a determinant region (amino acid [aa] 127–128) to create a novel HBsAg vaccine vector allowing surface orientation of the inserted sequence. We inserted sequences of various lengths from hypervariable region 1 (HVR1) of the hepatitis C virus (HCV) E2 protein containing immunodominant epitopes and demonstrated secretion of the recombinant HBsAg VLPs from transfected mammalian cells. A number of different recombinant proteins were synthesized, and HBsAg VLPs containing inserts up to 36 aa were secreted with an efficiency similar to that of wild-type HBsAg. The HVR1 region exposed on the particles retained an antigenic structure similar to that recognized immunologically during natural infection. VLPs containing epitopes from either HCV-1a or -1b strains were produced that induced strain-specific antibody responses in immunized mice. Injection of a combination of these VLPs induced antibodies against both HVR1 epitopes that resulted in higher titers than were achieved by vaccination with the individual VLPs, suggesting a synergistic effect. This may lead to the development of recombinant particles which are able to induce a broad anti-HCV immune response against the HCV quasispecies or other quasispecies-like infectious agents.
Nuclear Localization and Shuttling of Herpes Simplex Virus Tegument Protein VP13/14
Authors: Donnelly Michelle , Elliott Gillian 
Published: July 2002

ABSTRACT
The herpes simplex virus type 1 gene UL47 encodes the tegument proteins referred to collectively as VP13/14, which are believed to be differentially modified forms of the same protein. Here we show that the major product of the UL47 gene during transient expression is VP14, suggesting that some feature of virus infection is required to produce VP13. We have tagged VP13/14 with green fluorescent protein and have demonstrated that the protein is targeted efficiently to the nucleus, where it often localizes in numerous punctate domains. Furthermore, we show that removal of the N-terminal 127 residues of the protein abrogates nuclear accumulation, and we have identified a 14-amino-acid peptide from this region that is sufficient to function as a nuclear targeting signal and transport a heterologous protein to the nucleus. This short peptide contains two runs of four arginine residues, suggesting that the VP13/14 nuclear localization signal may behave in a manner similar to that of the arginine-rich nuclear localization signals of the retrovirus transactivator proteins Tat, Rev, and Rex. In addition, by using heterokaryon assays, we show that VP13/14 is capable of shuttling between the nucleus and cytoplasm of the cell, a property that may be attributed to three leucine-rich stretches in the C-terminal half of the protein that again bear similarity to the nuclear export signals of Rev and Rex. This is the first demonstration of a tegument protein that is specifically targeted to the nucleus, a feature which may be relevant both during virus entry, when VP13/14 enters the cell as a component of the tegument, and at later times, when large amounts of newly synthesized VP13/14 are present within the cell.
Differences in Cytokine and Chemokine Responses during Neurological Disease Induced by Polytropic Murine Retroviruses Map to Separate Regions of the Viral Envelope Gene
Authors: Peterson Karin E. , Robertson Shelly J. , Portis John L. , Chesebro Bruce 
Published: July 2002

ABSTRACT

Infection of the central nervous system (CNS) by several viruses can lead to upregulation of proinflammatory cytokines and chemokines. In immunocompetent adults, these molecules induce prominent inflammatory infiltrates. However, with immunosuppressive retroviruses, such as human immunodeficiency virus (HIV), little CNS inflammation is observed yet proinflammatory cytokines and chemokines are still upregulated in some patients and may mediate pathogenesis. The present study examined expression of cytokines and chemokines in brain tissue of neonatal mice infected with virulent (Fr98) and avirulent (Fr54) polytropic murine retroviruses. While both viruses infect microglia and endothelia primarily in the white matter areas of the CNS, only Fr98 induces clinical CNS disease. The pathology consists of gliosis with minimal morphological changes and no inflammation, similar to HIV. In the present experiments, mice infected with Fr98 had increased cerebellar mRNA levels of proinflammatory cytokines tumor necrosis factor alpha (TNF-α), TNF-β, and interleukin-1α and chemokines macrophage inflammatory protein-1α (MIP-1α), MIP-1β, monocyte chemoattractant protein 1 (MCP-1), gamma-interferon-inducible protein 10 (IP-10), and RANTES compared to mice infected with Fr54 or mock-infected controls. The increased expression of these genes occurred prior to the development of clinical symptoms, suggesting that these cytokines and chemokines might be involved in induction of neuropathogenesis. Two separate regions of the Fr98 envelope gene are associated with neurovirulence. CNS disease associated with the N-terminal portion of the Fr98
env
gene was preceded by upregulation of cytokines and chemokines. In contrast, disease associated with the central region of the Fr98
env
gene showed no upregulation of cytokines or chemokines and thus did not require increased expression of these genes for disease induction.
New World Arenavirus Clade C, but Not Clade A and B Viruses, Utilizes α-Dystroglycan as Its Major Receptor
Authors: Spiropoulou Christina F. , Kunz Stefan , Rollin Pierre E. , Campbell Kevin P. , Oldstone Michael B. A. 
Published: July 2002

ABSTRACT
α-Dystroglycan (α-DG) has been identified as a major receptor for lymphocytic choriomeningitis virus (LCMV) and Lassa virus, two Old World arenaviruses. The situation with New World arenaviruses is less clear: previous studies demonstrated that Oliveros virus also exhibited high-affinity binding to α-DG but that Guanarito virus did not. To extend these initial studies, several additional Old and New World arenaviruses were screened for entry into mouse embryonic stem cells possessing or lacking α-DG. In addition, representative viruses were further analyzed for direct binding to α-DG by means of a virus overlay protein blot assay technique. These studies indicate that Old World arenaviruses use α-DG as a major receptor, whereas, of the New World arenaviruses, only clade C viruses (i.e., Oliveros and Latino viruses) use α-DG as a major receptor. New World clade A and B arenaviruses, which include the highly pathogenic Machupo, Guanarito, Junin, and Sabia viruses, appear to use a different receptor or coreceptor for binding. Previous studies with LCMV have suggested the need for a small aliphatic amino acid at LCMV GP1 glycoprotein amino acid position 260 to allow high-affinity binding to α-DG. As reported herein, this requirement appears to be broadly applicable to the arenaviruses as determined by more extensive analysis of α-DG receptor usage and GP1 sequences of Old and New World arenaviruses. In addition, GP1 amino acid position 259 also appears to be important, since all arenaviruses showing high-affinity α-DG binding possess a bulky aromatic amino acid (tyrosine or phenylalanine) at this position.
Regulation of Hepatocyte Nuclear Factor 1 Activity by Wild-Type and Mutant Hepatitis B Virus X Proteins
Authors: Li Jie , Xu Zhenming , Zheng Yanyan , Johnson Deborah L. , Ou Jing-hsiung 
Published: July 2002

ABSTRACT

The hepatitis B virus (HBV) core promoter regulates the transcription of two related RNA products named precore RNA and core RNA. Previous studies indicate that a double-nucleotide mutation that occurs frequently during chronic HBV infection converts a nuclear receptor binding site in the core promoter to the binding site of the transcription factor hepatocyte nuclear factor-1 (HNF-1) and specifically suppresses the transcription of the precore RNA. This mutation also changes two codons in the overlapping X protein coding sequence. In this report, we demonstrate that the X protein and its mutant X
mt
can physically bind to HNF-1 both in vitro and in vivo. Further analyses indicate that both X and X
mt
can enhance the gene transactivation and the DNA binding activities of HNF-1. This finding demonstrates for the first time that the X protein can stimulate the DNA binding activity of a homeodomain transcription factor. Interestingly, while both X and X
mt
can stimulate the HNF-1 activities, they differ in their effects: a smaller amount of X
mt
is needed to generate greater transactivation and DNA binding activities of HNF-1. This functional difference between X and X
mt
may have important implications in HBV pathogenesis and is apparently why they have different effects on the core promoter bearing the HNF-1 binding site.
Dominance of CD8 Responses Specific for Epitopes Bound by a Single Major Histocompatibility Complex Class I Molecule during the Acute Phase of Viral Infection
Authors: Mothé Bianca R. , Horton Helen , Carter Donald K. , Allen Todd M. , Liebl Max E. , Skinner Pam , Vogel Thorsten U. , Fuenger Sarah , Vielhuber Kathy , Rehrauer William , Wilson Nancy , Franchini Genoveffa , Altman John D. , Haase Ashley , Picker Louis J. , Allison David B. , Watkins David I. 
Published: July 2002

ABSTRACTCytotoxic T-lymphocyte (CTL) responses are thought to control human immunodeficiency virus replication during the acute phase of infection. Understanding the CD8+T-cell immune responses early after infection may, therefore, be important to vaccine design. Analyzing these responses in humans is difficult since few patients are diagnosed during early infection. Additionally, patients are infected by a variety of viral subtypes, making it hard to design reagents to measure their acute-phase immune responses. Given the complexities in evaluating acute-phase CD8+responses in humans, we analyzed these important immune responses in rhesus macaques expressing a common rhesus macaque major histocompatibility complex class I molecule (Mamu-A*01) for which we had developed a variety of immunological assays. We infected eight Mamu-A*01-positive macaques and five Mamu-A*01-negative macaques with the molecularly cloned virus SIVmac239 and determined all of the simian immunodeficiency virus-specific CD8+T-cell responses against overlapping peptides spanning the entire virus. We also monitored the evolution of particular CD8+T-cell responses by tetramer staining of peripheral lymphocytes as well as lymph node cells in situ. In this first analysis of the entire CD8+immune response to autologous virus we show that between 2 and 12 responses are detected during the acute phase in each animal. CTL against the early proteins (Tat, Rev, and Nef) and against regulatory proteins Vif and Vpr dominated the acute phase. Interestingly, CD8+responses against Mamu-A*01-restricted epitopes Tat28-35SL8 and Gag181-189CM9 were immunodominant in the acute phase. After the acute phase, however, this pattern of reactivity changed, and the Mamu-A*01-restricted response against the Gag181-189CM9 epitope became dominant. In most of the Mamu-A*01-positive macaques tested, CTL responses against epitopes bound by Mamu-A*01 dominated the CD8+cellular immune response.
Phylogenetic Analysis of Varicella-Zoster Virus: Evidence of Intercontinental Spread of Genotypes and Recombination
Authors: Muir Winsome Barrett , Nichols Richard , Breuer Judith 
Published: July 2002

ABSTRACT
A heteroduplex mobility assay was used to identify variants of varicella-zoster virus circulating in the United Kingdom and elsewhere. Within the United Kingdom, 58 segregating sites were found out of the 23,266 examined (0.25%), and nucleotide diversity was estimated to be 0.00063. These are an order of magnitude smaller than comparable estimates from herpes simplex virus type 1. Sixteen substitutions were nonsynonymous, the majority of which were clustered within surface-expressed proteins. Extensive genetic correlation between widely spaced sites indicated that recombination has been rare. Phylogenetic analysis of varicella-zoster viruses from four continents distinguished at least three major genetic clades. Most geographical regions contained only one of these three strains, apart from the United Kingdom and Brazil, where two or more strains were found. There was minimal genetic differentiation (one or fewer substitutions in 1,895 bases surveyed) between the samples collected from Africa (Guinea Bissau, Zambia) and the Indian subcontinent (Bangladesh, South India), suggesting recent rapid spread and/or low mutation rates. The geographic pattern of strain distribution would favor a major influence of the former. The genetic uniformity of most virus populations makes recombination difficult to detect. However, at least one probable recombinant between two of the major strains was found among the samples originating from Brazil, where mixtures of genotypes co-occur.
Porcine Endogenous Retrovirus Transmission Characteristics of an Inbred Herd of Miniature Swine
Authors: Oldmixon Beth A. , Wood James C. , Ericsson Thomas A. , Wilson Carolyn A. , White-Scharf Mary E. , Andersson Goran , Greenstein Julia L. , Schuurman Henk-Jan , Patience Clive 
Published: July 2002

ABSTRACT
Here we report the identification of inbred miniature swine that failed to produce human-tropic replication-competent porcine endogenous retroviruses (HTRC PERVs), using in vitro coculture assays. When HTRC PERVs were isolated from transmitting animals, all were recombinant viruses, with the receptor-binding domain of PERV-A combining with PERV-C-related sequences.
Immune-Mediated Protection from Measles Virus-Induced Central Nervous System Disease Is Noncytolytic and Gamma Interferon Dependent
Authors: Patterson Catherine E. , Lawrence Diane M. P. , Echols Lisa A. , Rall Glenn F. 
Published: July 2002

ABSTRACTNeurons of the mammalian central nervous system (CNS) are an essential and largely nonrenewable cell population. Thus, virus infections that result in neuronal depletion, either by virus-mediated cell death or by induction of the cytolytic immune response, could cause permanent neurological impairment of the host. In a transgenic mouse model of measles virus (MV) infection of neurons, we have previously shown that the host T-cell response was required for resolution of infection in susceptible adult mice. In this report, we show that this protective response did not result in neuronal death, even during the peak of T-cell infiltration into the brain parenchyma. When susceptible mice were intercrossed with specific immune knockout mice, a critical role for gamma interferon (IFN-γ) was identified in protection against MV infection and CNS disease. Moreover, the addition of previously activated splenocytes or recombinant murine IFN-γ to MV-infected primary neurons resulted in the inhibition of viral replication in the absence of neuronal death. Together, these data support the hypothesis that the host immune response can promote viral clearance without concomitant neuronal loss, a process that appears to be mediated by cytokines.
Solubility in the Glycine-H3BO3-H2O System
Authors: Eysseltová Jitka , Dosoudilová Jana 
Published: July 2002

Solubility isotherms in the title system were measured at 0, 25, 50, and 70 °C. Regression straight line equations interrelating the solubilities of boric acid and glycine were derived. The activity of water in saturated solutions of the system at 25 °C was determined by vapour pressure measurements.
The slow component of V̇o2in professional cyclists
Authors: Lucía Alejandro , Hoyos Jesús , Chicharro José L 
Published: July 2002

Objectives—To analyse the slow component of oxygen uptake (V̇o2) in professional cyclists and to determine whether this phenomenon is due to altered neuromuscular activity, as assessed by surface electromyography (EMG).Methods—The following variables were measured during 20 minute cycle ergometer tests performed at about 80% of V̇o2maxin nine professional road cyclists (mean (SD) age 26 (2) years; V̇o2max 72.6 (2.2) ml/kg/min): heart rate (HR), gas exchange variables (V̇o2, ventilation (V̇e), tidal volume (VT), breathing frequency (fb), ventilatory equivalents for oxygen and carbon dioxide (V̇e/V̇o2and V̇e/V̇co2respectively), respiratory exchange ratio (RER), and end tidal Po2and Pco2(Peto2and Petco2respectively)), blood variables (lactate, pH, and [HCO3−]) and EMG data (root mean from square voltage (rms-EMG) and mean power frequency (MPF)) from the vastus lateralis muscle.Results—The mean magnitude of the slow component (from the end of the third minute to the end of exercise) was 130 (0.04) ml in 17 minutes or 7.6 ml/min. Significant increases from three minute to end of exercise values were found for the following variables: V̇o2(p<0.01), HR (p<0.01), V̇e(p<0.05), fb(p<0.01), V̇e/V̇o2(p<0.05), V̇e/V̇co2(p<0.01), Peto2(p<0.05), and blood lactate (p<0.05). In contrast, rms-EMG and MPF showed no change (p>0.05) throughout the exercise tests.Conclusions—A significant but small V̇o2slow component was shown in professional cyclists during constant load heavy exercise. The results suggest that the primary origin of the slow component is not neuromuscular factors in these subjects, at least for exercise intensities up to 80% of V̇o2max.
Views of chartered physiotherapists on the psychological content of their practice: a preliminary study in the United Kingdom
Authors: Hemmings B , Povey L 
Published: July 2002

Background: Although research into the psychological aspects of sports injury is increasing and psychological interventions have been identified as important in the rehabilitation process, few studies have focused on how sports medicine practitioners deal with psychological problems.Objective: To investigate the perceptions of English chartered physiotherapists on the psychological content of their practice.Methods: The Physiotherapist and Sport Psychology Questionnaire (PSPQ) was adapted slightly from the Athletic Trainer and Sport Psychology Questionnaire and used in this study. A survey package comprising a PSPQ, introductory letter, and self addressed envelope was mailed to 179 chartered physiotherapists registered in the England Eastern Region Sports Medicine Directory.Results: In total, 90 (50% response rate) questionnaires were returned. The sample consisted of 67 women and 23 men with a mean (SD) age of 40.1 (5.4) years and 9.2 (3.1) years of experience as chartered physiotherapists. Descriptive statistical and qualitative analysis showed that physiotherapists believed athletes were often psychologically affected by injury. The physiotherapists also reported often using psychological techniques when treating injured athletes, but few reported having access to a sport psychologist for referral.Conclusions: This research indicates that future physiotherapy education may need more emphasis on the psychological aspect of injury, and seek to increase knowledge on the potential of using psychological interventions within a physiotherapy rehabilitation programme. Furthermore, some form of referral network should be established between chartered physiotherapists and sport psychologists.
Asbestosis and lobar site of lung cancer: Table 1
Authors: Weiss William 
Published: July 2002

OBJECTIVETo assess the evidence for the hypothesis that lung cancer has a predilection for the lower lobes in workers with asbestosis.METHODA review of the available literature with relevant information.RESULTSSix published reports were analysed. In four studies limited to series of cases with diagnoses of asbestosis, three showed lower lobe predominance of lung cancer whereas the fourth study included cases in which the radiographic readings did not meet the usual criterion of profusion for asbestosis. One cohort study showed lower lobe predominance; the other reported only 33% lower lobe cancers compared with 20% in unexposed controls.CONCLUSIONThere is some support for the hypothesis but more studies are needed.