bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitosis-Specific Hyperphosphorylation of Epstein-Barr Virus Nuclear Antigen 2 Suppresses Its Function
Authors: Yue Wei , Davenport Matthew G. , Shackelford Julia , Pagano Joseph S. 
Published: March 2004

ABSTRACT

The Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA-2) is a key gene expressed in EBV type III latent infection that can transactivate numerous promoters, including those for all the other type III viral latency genes as well as cellular genes responsible for cell proliferation. EBNA-2 is essential for EBV-mediated immortalization of primary B lymphocytes. We now report that EBNA-2, a phosphoprotein, is hyperphosphorylated specifically in mitosis. Evidence that the cyclin-dependent kinase p34
cdc2
may be involved in this hyperphosphorylation includes (i) coimmunoprecipitation of EBNA-2 and p34
cdc2
, suggesting physical association; (ii) temporal correlation between hyperphosphorylation of EBNA-2 and an increase in p34
cdc2
kinase activity; and (iii) ability of purified p34
cdc2
/cyclin B1 kinase to phosphorylate EBNA-2 in vitro. Hyperphosphorylation of EBNA-2 appears to suppress its ability to transactivate the latent membrane protein 1 (LMP-1) promoter by about 50%. The association between EBNA-2 and PU.1 is also decreased by about 50% in M-phase-arrested cells, as shown by coimmunoprecipitation from cell lysates, suggesting that hyperphosphorylation of EBNA-2 impairs its affinity for PU.1. Finally, endogenous LMP-1 mRNA levels in M phase are around 55% of those in asynchronously growing cells. These results suggest that regulation of gene expression during type III latency may be regulated in a cell-cycle-related manner.
The Vaccinia Virus K1L Gene Product Inhibits Host NF-κB Activation by Preventing IκBα Degradation
Authors: Shisler Joanna L. , Jin Xiao-Lu 
Published: March 2004

ABSTRACTVaccinia virus wild-type strains such as Ankara and WR synthesize proteins capable of inhibiting the activation of host NF-κB, a family of transcription factors that regulate the expression of inflammatory genes. In contrast, an infection by the attenuated MVA strain, whose genome lacks many immunoregulatory genes present in the DNA of its Ankara parent, induces NF-κB activation. Insertion of NF-κB inhibitory genes into the MVA DNA, then, would alter the MVA phenotype. By this method, a 5.2-kb region of Ankara DNA containing the K1L gene and two other genes that are absent in the MVA genome that was identified as NF-κB was inhibited in cells infected with the MVA/5.2kb virus. To determine if K1L was responsible, the relevant biological properties of both a recombinant MVA containing a copy of the WR strain's K1L (MVA/K1L) and a WR deletion mutant lacking the K1L gene (ΔK1L) were examined. Indeed, unlike its progenitor, the altered MVA halted degradation of the host regulatory protein IκBα—a key event in the pathway of transcriptional activation by NF-κB factors. Moreover, MVA/K1L gained the ability to repress artificially contrived and natural NF-κB-regulated expression of a transfected luciferase and the cellular tumor necrosis factor gene, respectively. In contrast, although these functions could also be performed by WR, the ΔK1L virus lost these abilities. Thus, one apparent molecular function of K1L is to prevent IκBα degradation. This impediment to NF-κB-induced host proinflammatory gene expression, in turn, might enhance virus survival.
Differential Tissue-Specific Regulation of Antiviral CD8+T-Cell Immune Responses during Chronic Viral Infection
Authors: Zhou Shenghua , Ou Rong , Huang Lei , Price Graeme E. , Moskophidis Demetrius 
Published: March 2004

ABSTRACTThe hallmarks of the immune response to viral infections are the expansion of antigen-specific CD8+cytotoxic T lymphocytes (CTLs) after they encounter antigen-presenting cells in the lymphoid tissues and their subsequent redistribution to nonlymphoid tissues to deal with the pathogen. Control mechanisms exist within CTL activation pathways to prevent inappropriate CTL responses against disseminating infections with a broad distribution of pathogen in host tissues. This is demonstrated during overwhelming infection with the noncytolytic murine lymphocytic choriomeningitis virus, in which clonal exhaustion (anergy and/or deletion) of CTLs prevents immune-mediated pathology but allows persistence of the virus. The mechanism by which the immune system determines whether or not to mount a full response to such infections is unknown. Here we present data showing that the initial encounter of specific CTLs with infected cells in lymphoid tissues is critical for this decision. Whether the course of the viral infection is acute or persistent for life primarily depends on the degree and kinetics of CTL exhaustion in infected lymphoid tissues. Virus-driven CTL expansion in lymphoid tissues resulted in the migration of large quantities of CTLs to nonlymphoid tissues, where they persisted at stable levels. Surprisingly, although virus-specific CTLs were rapidly clonally exhausted in lymphoid tissues under conditions of chronic infection, a substantial number of them migrated to nonlymphoid tissues, where they retained an effector phenotype for a long time. However, these cells were unable to control the infection and progressively lost their antiviral capacities (cytotoxicity and cytokine secretion) in a hierarchical manner before their eventual physical elimination. These results illustrate the differential tissue-specific regulation of antiviral T-cell responses during chronic infections and may help us to understand the dynamic relationship between antigen and T-cell populations in many persistent infections in humans.
Transgenic Mice Expressing the Nucleoprotein of Borna Disease Virus in either Neurons or Astrocytes: Decreased Susceptibility to Homotypic Infection and Disease
Authors: Rauer Mathias , Götz Jürgen , Schuppli Daniel , Staeheli Peter , Hausmann Jürgen 
Published: March 2004

ABSTRACTThe nucleoprotein (N) of Borna disease virus (BDV) is the major target of the disease-inducing antiviral CD8 T-cell response in the central nervous system of mice. We established two transgenic mouse lines which express BDV-N in either neurons (Neuro-N) or astrocytes (Astro-N). Despite strong transgene expression, neurological disease or gross behavioral abnormalities were not observed in these animals. When Neuro-N mice were infected as adults, replication of BDV was severely impaired and was restricted to brain areas with a low density of transgene-expressing cells. Notably, the virus failed to replicate in the transgene-expressing granular and pyramidal neurons of the hippocampus (which are usually the preferred host cells of BDV). When Neuro-N mice were infected within the first 5 days of life, replication of BDV was not suppressed in most neurons, presumably because the onset of transgene expression in the brain occurred after these cells became infected with BDV. Astro-N mice remained susceptible to BDV infection, but they were resistant to BDV-induced neurological disorder. Unlike their nontransgenic littermates, Neuro-N mice with persistent BDV infection did not develop neurological disease after immunization with a vaccinia virus vector expressing BDV-N. In contrast to the situation in wild-type mice, this treatment also failed to induce N-specific CD8 T cells in the spleens of both transgenic mouse lines. Thus, while resistance to BDV infection in N-expressing neurons appeared to result from untimely expression of a viral nucleocapsid component, the resistance to BDV-induced neuropathology probably resulted from immunological tolerance.
Comparative Molecular Analysis of the Abnormal Prion Protein in Field Scrapie Cases and Experimental Bovine Spongiform Encephalopathy in Sheep by Use of Western Blotting and Immunohistochemical Methods
Authors: Lezmi Stéphane , Martin Stuart , Simon Stéphanie , Comoy Emmanuel , Bencsik Anna , Deslys Jean-Philippe , Grassi Jacques , Jeffrey Martin , Baron Thierry 
Published: March 2004

ABSTRACT

Since the appearance of bovine spongiform encephalopathy (BSE) in cattle and its linkage with the human variant of Creutzfeldt-Jakob disease, the possible spread of this agent to sheep flocks has been of concern as a potential new source of contamination. Molecular analysis of the protease cleavage of the abnormal prion protein (PrP), by Western blotting (PrP
res
) or by immunohistochemical methods (PrP
d
), has shown some potential to distinguish BSE and scrapie in sheep. Using a newly developed enzyme-linked immunosorbent assay, we identified 18 infected sheep in which PrP
res
showed an increased sensitivity to proteinase K digestion. When analyzed by Western blotting, two of them showed a low molecular mass of unglycosylated PrP
res
as found in BSE-infected sheep, in contrast to other naturally infected sheep. A decrease of the labeling by P4 monoclonal antibody, which recognizes an epitope close to the protease cleavage site, was also found by Western blotting in the former two samples, but this was less marked than in BSE-infected sheep. These two samples, and all of the other natural scrapie cases studied, were clearly distinguishable from those from sheep inoculated with the BSE agent from either French or British cattle by immunohistochemical analysis of PrP
d
labeling in the brain and lymphoid tissues. Final characterization of the strain involved in these samples will require analysis of the features of the disease following infection of mice, but our data already emphasize the need to use the different available methods to define the molecular properties of abnormal PrP and its possible similarities with the BSE agent.
Movement Protein of a Closterovirus Is a Type III Integral Transmembrane Protein Localized to the EndoplasmicReticulum
Authors: Peremyslov Valera V. , Pan Yung-Wei , Dolja Valerian V. 
Published: March 2004

ABSTRACTCell-to-cell movement of beet yellows closterovirus requires four structural proteins and a 6-kDa protein (p6) that is a conventional, nonstructural movement protein. Here we demonstrate that either virus infection or p6 overexpression results in association of p6 with the rough endoplasmic reticulum. The p6 protein possesses a single-span, transmembrane, N-terminal domain and a hydrophilic, C-terminal domain that is localized on the cytoplasmic face of the endoplasmic reticulum. In the infected cells, p6 forms a disulfide bridge via a cysteine residue located near the protein's N terminus. Mutagenic analyses indicated that each of the p6 domains, as well as protein dimerization, is essential for p6 function in virus movement.
The Subcellular Distribution of Multigene Family 110 Proteins of African Swine Fever Virus Is Determined by Differences in C-Terminal KDEL Endoplasmic Reticulum Retention Motifs
Authors: Netherton Christopher , Rouiller Isabelle , Wileman Thomas 
Published: March 2004

ABSTRACT

African swine fever virus (ASFV) is a large double-stranded DNA virus that replicates in discrete areas in the cytosol of infected cells called viral factories. Recent studies have shown that assembling virions acquire their internal envelopes through enwrapment by membranes derived from the endoplasmic reticulum (ER). However, the mechanisms that underlie the formation of viral factories and progenitor viral membranes are as yet unclear. Analysis of the published genome of the virus revealed a conserved multigene family that encodes proteins with hydrophobic signal sequences, indicating possible translocation into the ER lumen. Strikingly, two of these genes,
XP124L
and
Y118L
, encoded proteins with KDEL-like ER retention motifs. Analysis of
XP124L
and
Y118L
gene product by biochemical and immunofluorescence techniques showed that the proteins were localized to pre-Golgi compartments and that the KEDL motif at the C terminus of pXP124L was functional.
XP124L
expression, in the absence of other ASFV genes, had a dramatic effect on the contents of the ER that was dependent precisely on the C-terminal sequence KEDL. The normal subcellular distribution of a number of proteins resident to this important, cellular organelle was drastically altered in cells expressing wild-type
XP124L
gene product. PXP124L formed unusual perinuclear structures that contained resident ER proteins, as well as proteins of the ER-Golgi intermediate compartment. The data presented here hint at a role for MGF110 gene product in preparing the ER for its role in viral morphogenesis; this and other potential functions are discussed.
Positive Selection Detection in 40,000 HumanImmunodeficiency Virus (HIV) Type 1 Sequences Automatically IdentifiesDrug Resistance and Positive Fitness Mutations in HIV Proteaseand ReverseTranscriptase
Authors: Chen Lamei , Perlina Alla , Lee Christopher J. 
Published: March 2004

ABSTRACT

Drug
resistance is a major problem in the treatment of AIDS, due to the very
high mutation rate of human immunodeficiency virus (HIV) and subsequent
rapid development of resistance to new drugs. Identification of
mutations associated with drug resistance is critical for both
individualized treatment selection and new drug design. We have
performed an automated mutation analysis of HIV Type 1 (HIV-1) protease
and reverse transcriptase (RT) from approximately 40,000 AIDS patient
plasma samples sequenced by Specialty Laboratories Inc. from 1999 to
mid-2002. This data set provides a nearly complete mutagenesis of HIV
protease and enables the calculation of statistically significant

K
a

/

K
s

values for each
individual amino acid mutation in protease and RT. Positive selection
(i.e., a

K
a

/

K
s

ratio of>
1, indicating increased reproductive fitness) detected 19 of
23 known drug-resistant mutation positions in protease and 20 of 34
such positions in RT. We also discovered 163 new amino acid mutations
in HIV protease and RT that are strong candidates for drug resistance
or fitness. Our results match available independent data on protease
mutations associated with specific drug treatments and mutations with
positive reproductive fitness, with high statistical significance (the
P
values for the observed matches to occur by random chance
are 10
−5.2
and 10
−16.6
,
respectively). Our mutation analysis provides a valuable resource for
AIDS research and will be available to academic researchers upon
publication at
http://www.bioinformatics.ucla.edu/HIV
.
Our data indicate that positive selection mapping is an analysis that
can yield powerful insights from high-throughput sequencing of rapidly
mutating
pathogens.
Second Sialic Acid Binding Site in Newcastle Disease Virus Hemagglutinin-Neuraminidase: Implications for Fusion
Authors: Zaitsev Viatcheslav , von Itzstein Mark , Groves Darrin , Kiefel Milton , Takimoto Toru , Portner Allen , Taylor Garry 
Published: March 2004

ABSTRACTParamyxoviruses are the leading cause of respiratory disease in children. Several paramyxoviruses possess a surface glycoprotein, the hemagglutinin-neuraminidase (HN), that is involved in attachment to sialic acid receptors, promotion of fusion, and removal of sialic acid from infected cells and progeny virions. Previously we showed that Newcastle disease virus (NDV) HN contained a pliable sialic acid recognition site that could take two states, a binding state and a catalytic state. Here we present evidence for a second sialic acid binding site at the dimer interface of HN and present a model for its involvement in cell fusion. Three different crystal forms of NDV HN now reveal identical tetrameric arrangements of HN monomers, perhaps indicative of the tetramer association found on the viral surface.
Low pH Is Required for Avian Sarcoma and Leukosis Virus Env-Induced Hemifusion and Fusion Pore Formation but Not for Pore Growth
Authors: Melikyan G. B. , Barnard R. J. O. , Markosyan R. M. , Young J. A. T. , Cohen F. S. 
Published: March 2004

ABSTRACT
Binding of avian sarcoma and leukosis virus (ASLV) to its cognate receptor on the cell surface causes conformational changes in its envelope protein (Env). It is currently debated whether low pH is required for ASLV infection. To elucidate the role of low pH, we studied the association between ASLV subgroup B (ASLV-B) and liposomes and fusion between effector cells expressing Env from ASLV-A and ASLV-B and target cells expressing cognate receptors. Neither EnvA nor EnvB promoted cell-cell fusion at neutral pH, but lowering the pH resulted in quick and extensive fusion. As expected for a low-pH-triggered reaction, fusion was a steep function of pH. Steps that required low pH were identified. Binding a soluble form of the receptor caused ASLV-B to hydrophobically associate with liposome membranes at neutral pH, indicating that low pH is not required for insertion of Env's fusion peptides into membranes. But both cell-cell hemifusion and fusion pore formation were pH dependent. It is proposed that fusion peptide insertion stabilizes the conformation of ASLV Env into a form that can be acted upon by low pH. At this point, but not before, low pH can induce fusion and is in fact required for fusion to occur. However, low pH is no longer necessary after formation of the initial fusion pore: pore enlargement does not require low pH.
Acupuncture for chronic headache in primary care: large, pragmatic, randomised trial
Authors: Vickers Andrew J , Rees Rebecca W , Zollman Catherine E , McCarney Rob , Smith Claire M , Ellis Nadia , Fisher Peter , Van Haselen Robbert 
Published: March 2004

AbstractObjective To determine the effects of a policy of “use acupuncture” on headache, health status, days off sick, and use of resources in patients with chronic headache compared with a policy of “avoid acupuncture.”Design Randomised, controlled trial.Setting General practices in England and Wales.Participants 401 patients with chronic headache, predominantly migraine.Interventions Patients were randomly allocated to receive up to 12 acupuncture treatments over three months or to a control intervention offering usual care.Main outcome measures Headache score, SF-36 health status, and use of medication were assessed at baseline, three, and 12 months. Use of resources was assessed every three months.Results Headache score at 12 months, the primary end point, was lower in the acupuncture group (16.2, SD 13.7, n = 161, 34%
reduction from baseline) than in controls (22.3, SD 17.0, n = 140, 16% reduction from baseline). The adjusted difference between means is 4.6 (95% confidence interval 2.2 to 7.0; P = 0.0002). This result is robust to sensitivity analysis incorporating imputation for missing data. Patients in the acupuncture group experienced the equivalent of 22 fewer days of headache per year (8 to 38). SF-36 data favoured acupuncture, although differences reached significance only for physical role functioning, energy, and change in health. Compared with controls, patients randomised to acupuncture used 15% less medication (P = 0.02), made 25% fewer visits to general practitioners (P = 0.10), and took 15% fewer days off sick (P = 0.2).Conclusions Acupuncture leads to persisting, clinically relevant benefits for primary care patients with chronic headache, particularly migraine. Expansion of NHS acupuncture services should be considered.
Does it matter what a hospital is “high volume” for? Specificity of hospital volume-outcome associations for surgical procedures: analysis of administrative data
Authors: Urbach David R , Baxter Nancy N 
Published: March 2004

AbstractObjective To determine whether the improved outcome of a surgical procedure in high volume hospitals is specific to the volume of the same procedure.Design and setting Analysis of secondary data in Ontario, Canada.Participants Patients having an oesophagectomy, colorectal resection for cancer, pancreaticoduodenectomy, major lung resection for cancer, or repair of an unruptured abdominal aortic aneurysm between 1994 and 1999.Main outcome measures Odds ratio for death within 30 days of surgery in relation to the hospital volume of the same surgical procedure and the hospital volume of the other four procedures. Estimates were adjusted for age, sex, and comorbidity and accounted for hospital level clustering.Results With the exception of colorectal resection, 30 day mortality seemed to be inversely related not only to the hospital volume of the same procedure but also to the hospital volume of most of the other procedures. In some cases the effect of the volume of a different procedure was stronger than the effect of the volume of the same procedure. For example, the association of mortality from pancreaticoduodenectomy with hospital volume of lung resection (odds ratio for death in hospitals with a high volume of lung resection compared with low volume 0.36, 95% confidence interval 0.23 to 0.57) was much stronger than the association of mortality from pancreaticoduodenectomy with hospital volume of pancreaticoduodenectomy (0.76, 0.44 to 1.32).Conclusion The inverse association between high volume of procedure and risk of operative death is not specific to the volume of the procedure being studied.
National cross sectional survey to determine whether the decision to delivery interval is critical in emergency caesarean section
Authors: Thomas Jane , Paranjothy Shantini , James David 
Published: March 2004

AbstractObjective To examine the association between decision to delivery interval and maternal and baby outcomes.Design National cross sectional survey.Setting Maternity units in England and Wales.Subjects reviewed 17 780 singleton births (99% of all births) delivered by emergency caesarean section in England and Wales between 1 May 2000 and 31 July 2000.Main outcome measures Association between decision to delivery interval and baby outcomes (Apgar scores of < 7 and < 4 at five minutes and stillbirth) and maternal outcomes (requirement for special care additional to routine care after caesarean section and where care was provided).Results Compared with babies delivered within 15 minutes, there was no difference in maternal or baby outcome for decision to delivery interval between 16 and 75 minutes. After 75 minutes, however, there was a significantly higher odds of a five minute Apgar score of < 7 (odds ratio 1.7, 95% confidence interval 1.2 to 2.4), and 50% increase in odds of special care additional to routine care for mothers.Conclusion A decision to delivery interval of 30 minutes is not an absolute threshold for influencing baby outcome. Decision to delivery intervals of more than 75 minutes are associated with poorer maternal and baby outcomes and should be avoided.
Cost effectiveness analysis of a randomised trial of acupuncture for chronic headache in primary care
Authors: Wonderling David , Vickers Andrew J , Grieve Richard , McCarney Rob 
Published: March 2004

AbstractObjective To evaluate the cost effectiveness of acupuncture in the management of chronic headache.Design Cost effectiveness analysis of a randomised controlled trial.Setting General practices in England and Wales.Participants 401 patients with chronic headache, predominantly migraine.Interventions Patients were randomly allocated to receive up to 12 acupuncture treatments over three months from appropriately trained physiotherapists, or to usual care alone.Main outcome measure Incremental cost per quality adjusted life year (QALY) gained.Results Total costs during the one year period of the study were on average higher for the acupuncture group (£403; $768;€598) than for controls (£217) because of the acupuncture practitioners' costs. The mean health gain from acupuncture during the one year of the trial was 0.021 quality adjusted life years (QALYs), leading to a base case estimate of £9180 per QALY gained. This result was robust to sensitivity analysis. Cost per QALY dropped substantially when the analysis incorporated likely QALY differences for the years after the trial.Conclusions Acupuncture for chronic headache improves health related quality of life at a small additional cost; it is relatively cost effective compared with a number of other interventions provided by the NHS.