bluuebunny/crossref_metadata_2025_split huggingface dataset:
The A20R Protein Is a Stoichiometric Component of the Processive Form of Vaccinia Virus DNA Polymerase
Authors: Klemperer Nancy , McDonald William , Boyle Kathleen , Unger Beth , Traktman Paula 
Published: July 2002

ABSTRACT

In vitro analysis of the catalytic DNA polymerase encoded by vaccinia virus has demonstrated that it is innately distributive, catalyzing the addition of <10 nucleotides per primer-template binding event in the presence of 8 mM MgCl
2
or 40 mM NaCl (W. F. McDonald and P. Traktman, J. Biol. Chem. 269:31190–31197, 1994). In contrast, cytoplasmic extracts isolated from vaccinia virus-infected cells contain a highly processive form of DNA polymerase, able to catalyze the replication of a 7-kb template per binding event under similar conditions. To study this holoenzyme, we were interested in purifying and characterizing the vaccinia virus processivity factor (VPF). Our previous studies indicated that VPF is expressed early after infection and has a native molecular mass of ∼48 kDa (W. F. McDonald, N. Klemperer, and P. Traktman, Virology 234:168–175, 1997). Using these criteria, we established a six-step chromatographic purification procedure, in which a prominent ∼45-kDa band was found to copurify with processive polymerase activity. This species was identified as the product of the A20 gene. By use of recombinant viruses that direct the overexpression of A20 and/or the DNA polymerase, we verified the physical interaction between the two proteins in coimmunoprecipitation experiments. We also demonstrated that simultaneous overexpression of A20 and the DNA polymerase leads to a specific and robust increase in levels of processive polymerase activity. Taken together, we conclude that the A20 gene encodes a component of the processive DNA polymerase complex. Genetic data that further support this conclusion are presented in the accompanying report, which documents that temperature-sensitive mutants with lesions in the A20 gene have a DNA
−
phenotype that correlates with a deficit in processive polymerase activity (A. Punjabi et al, J. Virol. 75:12308–12318, 2001).
Antiviral Effect of
N
-Butyldeoxynojirimycin against Bovine Viral Diarrhea Virus Correlates with Misfolding of E2 Envelope Proteins and Impairment of Their Association into E1-E2 Heterodimers
Authors: Branza-Nichita Norica , Durantel David , Carrouée-Durantel Sandra , Dwek Raymond A. , Zitzmann Nicole 
Published: July 2002

ABSTRACT

The iminosugar
N
-butyldeoxynojirimycin (
N
B-DNJ), an endoplasmic reticulum α-glucosidase inhibitor, has an antiviral effect against bovine viral diarrhea virus (BVDV). In this report, we investigate the molecular mechanism of this inhibition by studying the folding pathway of BVDV envelope glycoproteins in the presence and absence of
N
B-DNJ. Our results show that, while the disulfide-dependent folding of E2 glycoprotein occurs rapidly (2.5 min), the folding of E1 occurs slowly (30 min). Both BVDV envelope glycoproteins associate rapidly with calnexin and dissociate with different kinetics. The release of E1 from the interaction with calnexin coincides with the beginning of E1 and E2 association into disulfide-linked heterodimers. In the presence of
N
B-DNJ, the interaction of E1 and E2 with calnexin is prevented, leading to misfolding of the envelope glycoproteins and inefficient formation of E1-E2 heterodimers. The degree of misfolding and the lack of association of E1 and E2 into disulfide-linked complexes in the presence of
N
B-DNJ correlate with the dose-dependent antiviral effect observed for this iminosugar.
Langat Virus M Protein Is Structurally Homologous to prM
Authors: Holbrook Michael R. , Wang Heiman , Barrett Alan D. T. 
Published: July 2002

ABSTRACT
Langat (LGT) virus M protein has been generated in a recombinant system. Antiserum raised against the LGT virus M protein neutralizes tick-borne encephalitis serocomplex flaviviruses but not mosquito-borne flaviviruses, indicating that the M protein is exposed on the surface of virions. The antiserum recognizes intracellular LGT virus prM/M and binds to prM and M in Western blots of whole-cell lysates and purified virus, respectively. These data suggest that the prM and M proteins are structurally similar under native conditions and support the hypothesis that the “pr” portion of prM facilitates proper folding of the M protein for expression on the virion surface.
Mutation Spectra of Herpes Simplex Virus Type 1 Thymidine Kinase Mutants
Authors: Lu Qiaosheng , Hwang Ying T. , Hwang Charles B. C. 
Published: July 2002

ABSTRACT

To examine whether the exonuclease activity intrinsic to the polymerase (Pol) of herpes simplex virus type 1 can influence the mutational spectra, we applied the denaturing gradient gel electrophoresis (DGGE) system combined with sequencing to characterize thymidine kinase mutants isolated from both the wild-type virus and a mutant deficient in exonuclease activity, Y7. Wild-type viruses produced predominately frameshift mutations (67%), whereas Y7 replicated a significantly lower proportion of frameshifts (21%;
P
< 0.005). Furthermore, the majority of substitutions were transitional changes in both groups, although they distributed differently. The implications of these findings are discussed.
Murine Coronavirus Replication-Induced p38 Mitogen-Activated Protein Kinase Activation Promotes Interleukin-6 Production and Virus Replication in Cultured Cells
Authors: Banerjee Sangeeta , Narayanan Krishna , Mizutani Tetsuya , Makino Shinji 
Published: July 2002

ABSTRACTAnalyses of mitogen-activated protein kinases (MAPKs) in a mouse hepatitis virus (MHV)-infected macrophage-derived J774.1 cell line showed activation of two MAPKs, p38 MAPK and c-Jun N-terminal kinase (JNK), but not of extracellular signal-regulated kinase (ERK). Activation of MAPKs was evident by 6 h postinfection. However, UV-irradiated MHV failed to activate MAPKs, which demonstrated that MHV replication was necessary for their activation. Several other MHV-permissive cell lines also showed activation of both p38 MAPK and JNK, which indicated that the MHV-induced stress-kinase activation was not restricted to any particular cell type. The upstream kinase responsible for activating MHV-induced p38 MAPK was the MAPK kinase 3. Experiments with a specific inhibitor of p38 MAPK, SB 203580, demonstrated that MHV-induced p38 MAPK activation resulted in the accumulation of interleukin-6 (IL-6) mRNAs and an increase in the production of IL-6, regardless of MHV-induced general host protein synthesis inhibition. Furthermore, MHV production was suppressed in SB 203580-treated cells, demonstrating that activated p38 MAPK played a role in MHV replication. The reduced MHV production in SB 203580-treated cells was, at least in part, due to a decrease in virus-specific protein synthesis and virus-specific mRNA accumulation. Interestingly, there was a transient increase in the amount of phosphorylation of the translation initiation factor 4E (eIF4E) in infected cells, and this eIF4E phosphorylation was p38 MAPK dependent; it is known that phosphorylated eIF4E enhances translation rates of cap-containing mRNAs. Furthermore, the upstream kinase responsible for eIF4E phosphorylation, MAPK-interacting kinase 1, was also phosphorylated and activated in response to MHV infection. Our data suggested that host cells, in response to MHV replication, activated p38 MAPK, which subsequently phosphorylated eIF4E to efficiently translate certain host proteins, including IL-6, during virus-induced severe host protein synthesis inhibition. MHV utilized this p38 MAPK-dependent increase in eIF4E phosphorylation to promote virus-specific protein synthesis and subsequent progeny virus production. Enhancement of virus-specific protein synthesis through virus-induced eIF4E activation has not been reported in any other viruses.
Membrane Association and Dimerization of a Cysteine-Rich, 16-Kilodalton Polypeptide Released from the C-Terminal Region of the Coronavirus Infectious Bronchitis Virus 1a Polyprotein
Authors: Ng Lisa F. P. , Liu D. X. 
Published: July 2002

ABSTRACT
More than 10 mature proteins processed from coronavirus gene 1-encoded polyproteins have been identified in virus-infected cells. Here, we report the identification of the most C-terminal cleavage product of the 1a polyprotein as a 16-kDa protein in infectious bronchitis virus-infected Vero cells. Indirect immunofluorescence demonstrated that the protein exhibits a distinct perinuclear punctate staining pattern, suggesting that it is associated with cellular membranes. Positive staining observed on nonpermeabilized cells indicates that the protein may get transported to the cell surface, but no secretion of the protein out of the cells was observed. Treatment of the membrane fraction prepared from cells expressing the 16-kDa protein with Triton X-100, a high pH, and a high concentration of salts showed that the protein may be tightly associated with intracellular membranes. Dual-labeling experiments demonstrated that the 16-kDa protein colocalized with the 5′-bromouridine 5′-triphosphate-labeled viral RNA, suggesting that it may be associated with the viral replication machinery. Sequence comparison of the 16-kDa protein with the equivalent products of other coronaviruses showed multiple conserved cysteine residues, and site-directed mutagenesis studies revealed that these conserved residues may contribute to dimerization of the 16-kDa protein. Furthermore, increased accumulation of the 16-kDa protein upon stimulation with epidermal growth factor was observed, providing preliminary evidence that the protein might be involved in the growth factor signaling pathway.
Search for Hepatitis C Virus Negative-Strand RNA Sequences and Analysis of Viral Sequences in the Central Nervous System: Evidence of Replication
Authors: Radkowski Marek , Wilkinson Jeffrey , Nowicki Marek , Adair Debra , Vargas Hugo , Ingui Craig , Rakela Jorge , Laskus Tomasz 
Published: July 2002

ABSTRACT

Patients with chronic hepatitis C are more likely to have significant changes in their physical and mental well-being than patients with liver disease of other etiology, and hepatitis C virus (HCV) has been occasionally implicated in diseases of the central nervous system. We analyzed the presence of the HCV negative-strand RNA sequence, which is the viral replicative intermediary, in autopsy brain tissue samples from six HCV-infected patients. Negative-strand HCV RNA was searched for by a strand-specific
Tth
-based reverse transcriptase PCR, and viral sequences amplified from brain tissue and serum were compared by single-strand conformational polymorphism analysis and direct sequencing. HCV RNA negative strands were detected in brain tissue in three patients. In two of these patients, serum- and brain-derived viral sequences were different and classified as belonging to different genotypes. In one of the latter patients, HCV RNA negative strands were detected in lymph node and, while being different from serum-derived sequences, were identical to those present in the brain. The results of the present study suggest that HCV can replicate in the central nervous system, probably in cells of the macrophage/monocyte lineage.
Heterologous Movement Protein Strongly Modifies the Infection Phenotype of Cucumber Mosaic Virus
Authors: Huppert Emese , Szilassy Dénes , Salánki Katalin , Divéki Zoltán , Balázs Ervin 
Published: July 2002

ABSTRACT

A hybrid virus (CMVcymMP) constructed by replacing the movement protein (MP) of cucumber mosaic cucumovirus (CMV) with that of cymbidium ringspot tombusvirus (CymRSV) was viable and could efficiently spread both cell to cell and long distance in host plants. The hybrid virus was able to move cell to cell in the absence of functional CP, whereas CP-deficient CMV was restricted to single inoculated cells. In several
Chenopodium
and
Nicotiana
species, the symptom phenotype of the hybrid virus infection was clearly determined by the foreign MP gene. In
Nicotiana debneyi
and
Nicotiana tabacum
cv. Xanthi, the hybrid virus could move systemically, contrary to CymRSV.
Hepatitis A Virus Suppresses Monocyte-to-Macrophage Maturation In Vitro
Authors: Wünschmann Sabina , Becker Britta , Vallbracht Angelika 
Published: July 2002

ABSTRACT
To analyze the pathogenetic mechanism of hematopoietic dysregulation associated with hepatitis A virus (HAV) infections, we studied the influence of HAV on monocyte (MO)-to-macrophage (MAC) maturation in vitro. Exposure of peripheral blood-derived mononuclear cells (MNC) to HAV led to diminished adherence of MO to plastic. Furthermore, HAV inhibited the ability of peripheral blood MO to differentiate toward MAC. Freshly isolated and 14-day-old MO cultures demonstrated reduced differentiation and decreased phagocytic capacity after challenge with HAV. Viral replication in MO/MAC cultures was confirmed by titration of infectious virus. We also determined the influence of HAV on the MO/MAC population in human long-term bone marrow cultures (LTBMCs). Inoculation of bone marrow MNC with HAV suppressed the establishment of an adherent stromal layer containing a reduced number of MAC. Furthermore, increased MO numbers in the nonadherent fraction of HAV-challenged LTBMCs are indicative of the disturbance of MO adherence. These findings suggest that HAV infection leads to a disorder of the mononuclear phagocytic system which may contribute to functional abnormalities of the bone marrow stroma.
Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands
Authors: Šima Jozef , Lauková Dáša , Brezová Vlasta 
Published: July 2002

Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.
Impact energy attenuation performance of football headgear
Authors: McIntosh Andrew S , McCrory Paul 
Published: July 2002

Objectives—Commercially available football head protectors were tested to determine their impact energy attenuation performance and ability to reduce the likelihood of concussion.Methods—Prospective study using standardised impact test methods with both rigid (magnesium) and Hybrid III headforms.Results—Eight commercially available head protectors from six manufacturers were tested. The magnitude of the headform accelerations increased as the drop height was increased, ranging from a minimum of 64 g from a height of 0.2 m to a maximum of 1132 g from a height of 0.6 m. The head injury criterion and maximum headform acceleration values followed a similar trend. A steep increase was noted in the magnitude of maximum headform acceleration and head injury criterion when the drop height was increased from 0.4 to 0.5 m. This indicates that the foam material was completely compressed at an impact energy above about 20 J and therefore offers little protection against impacts of greater severity. Repeated tests using a drop height of 0.3 m showed that some helmets exhibit a “memory” effect, whereby impact performance is reduced by up to 50% with repeated impacts.Conclusions—Laboratory tests indicate that current commercially available football headgear performance will not reduce the likelihood of concussion. The absence of internationally recognised standards for soft headgear designed to ameliorate concussion is a major deficiency in sports injury prevention.
Updated mortality among diverse operating segments of a petroleum company
Authors: Lewis R Jeffrey , Schnatter A Robert , Katz Arnold M , Thompson F S , Murray Neil , Jorgensen Gail , Thériault Gilles 
Published: July 2002

OBJECTIVESTo update mortality for 34 560 employees from diverse operating segments of a Canadian petroleum company; and to investigate potential relations with occupational factors.METHODSEmployees from 1964–83 were linked to the Canadian mortality data base to provide 11 years additional follow up. There were 6760 deaths and 750 683 person-years of follow up compared with 3909 and 428 190, respectively, in the earlier study. Analyses used standardised mortality ratios (SMRs) to compare worker cause specific mortality with the Canadian general population. Duration of employment and latency analyses were performed for causes previously found to be increased in this and other petroleum cohorts, as well as any findings of interest.RESULTSFor the period 1964–94, employees experienced significantly low overall mortality (SMR=0.86 men, SMR=0.80 women). Kidney cancer, which has been increased in some studies of petroleum workers, was not increased. Acute non-lymphocytic leukaemia in exposed operating segments was consistent with the expected or only slightly, non-significantly increased. The most notable finding was increased deaths from mesothelioma among refinery and petrochemical workers (SMR 8.68; 95% confidence interval (95% CI) 5.51 to 13.03), most of whom were long term employees in jobs with presumed exposure to asbestos (mechanical and pipefitters). Deaths from multiple myeloma among marketing and distribution workers, which were previously increased, remained increased (SMR 2.08; 95% CI 0.95 to 3.95) in the update period 1984–94; however, there was no clear pattern by duration of employment or latency. Aortic aneurysms, which also were previously significantly increased among marketing and distribution workers approached the expected in the update period (SMR 1.18; 95% CI 0.65–1.98). Analyses by duration of employment showed suggestive trends for aortic aneurysms, but earlier studies of this cohort have not found a relation between aortic aneurysms and exposure to hydrocarbons.CONCLUSIONThe additional 2851 deaths and 322 493 person-years of follow up strengthened the assessment of mortality patterns relative to occupational factors. With the exception of mesothelioma, no clear work related increases in disease were identified.
Ultrafine particles and nitrogen oxides generated by gas and electric cooking
Authors: Dennekamp M , Howarth S , Dick C A J , Cherrie J W , Donaldson K , Seaton A 
Published: July 2002

OBJECTIVESTo measure the concentrations of particles less than 100 nm diameter and of oxides of nitrogen generated by cooking with gas and electricity, to comment on possible hazards to health in poorly ventilated kitchens.METHODSExperiments with gas and electric rings, grills, and ovens were used to compare different cooking procedures. Nitrogen oxides (NOx) were measured by a chemiluminescent ML9841A NOxanalyser. A TSI 3934 scanning mobility particle sizer was used to measure average number concentration and size distribution of aerosols in the size range 10–500 nm.RESULTSHigh concentrations of particles are generated by gas combustion, by frying, and by cooking of fatty foods. Electric rings and grills may also generate particles from their surfaces. In experiments where gas burning was the most important source of particles, most particles were in the size range 15–40 nm. When bacon was fried on the gas or electric rings the particles were of larger diameter, in the size range 50–100 nm. The smaller particles generated during experiments grew in size with time because of coagulation. Substantial concentrations of NOXwere generated during cooking on gas; four rings for 15 minutes produced 5 minute peaks of about 1000 ppb nitrogen dioxide and about 2000 ppb nitric oxide.CONCLUSIONSCooking in a poorly ventilated kitchen may give rise to potentially toxic concentrations of numbers of particles. Very high concentrations of oxides of nitrogen may also be generated by gas cooking, and with no extraction and poor ventilation, may reach concentrations at which adverse health effects may be expected. Although respiratory effects of exposure to NOxmight be anticipated, recent epidemiology suggests that cardiac effects cannot be excluded, and further investigation of this is desirable.
Bilateral superselective arterial microcoil embolisation in delayed post-traumatic high flow priapism
Authors: Gujral S , MacDonagh R P , Cavanagh P M 
Published: July 2002

Abstract
High flow arteriogenic priapism is uncommon and usually occurs after trauma to the genitoperineal area. The onset of prolonged erection can be delayed and is often relatively pain free. Arteriography in this case illustrated the causative bilateral arteriocavernosal fistulae and pseudoaneurysms. Treatment consisted of staged bilateral superselective metallic microcoil embolisations, resulting in prompt detumescence. There were no complications. The patient had normal erectile function six months later. Recent concerns about erectile dysfunction with the bilateral use of permanent metallic coils appear to be unfounded.
Quadruple therapy for symptomatic spontaneous duodenal ulcer disease
Authors: Bateson M C 
Published: July 2002

Abstract

AIM
To investigate Helicobacter pylori eradication in duodenal ulcer patients with a new regimen, lansoprazole 30 mg daily for one or four weeks plus twice daily tetracycline 500 mg, clarithromycin 250 mg, and metronidazole 400 mg.

BACKGROUND
Spontaneous duodenal ulcer is regularly associated with H pylori, and permanent cure follows eradication of this bacterium. Numerous treatments have been proposed and none is ideal, possibly because of primary or acquired antibiotic resistance. Quadruple regimens with proton pump inhibitor therapy and three antibiotics offer promise as the most effective therapy.

METHODS
From November 1995 all patients with spontaneous duodenal ulcer were offered quadruple therapy. A month after completion a carbon 14 urea breath test (UBT) was performed. Sensitivity of H pylori to the antibiotics used was tested in 1992–3, 1996, and 1999.

RESULTS
A total of 331 patients were treated; 313 attended for a UBT, of which 299 were negative (95.5%). Of those patients who had an endoscopy with positive urease test immediately before treatment, 95/101 (94.0%) on lansoprazole for one week and 116/121 (95.8%) on lansoprazole for four weeks had a negative UBT. H pylori antibiotic sensitivity did not change.

CONCLUSION
This regimen produced some of the best results yet seen and may be generally recommended as first line therapy.
Prescription of eye drops
Authors: O'Sullivan E P , Malhotra R , Migdal C 
Published: July 2002

Abstract
The aim of this study was to assess whether patients have their ocular drops correctly prescribed during non-ophthalmic admissions to hospital. A retrospective review of notes of patients who were admitted to hospital for general medical or surgical care, while on regular eye drops at the time of admission was performed. Twenty two patients were on regular ocular medication when admitted. Only seven out of 22 patients had their eye drops correctly prescribed. Furthermore, six patients had been prescribed topical β-blockers, yet suffered from medical conditions that may have been aggravated by these drops. These findings demonstrate that the majority of patients on drops do not have their medication correctly prescribed during non-ophthalmic admissions to hospital. Also topical β-blockers continue to be inappropriately prescribed.