bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intracellular Trafficking of Gag and Env Proteins and Their Interactions Modulate Pseudotyping of Retroviruses
Authors: Sandrin Virginie , Muriaux Delphine , Darlix Jean-Luc , Cosset François-Loïc 
Published: June 2004

ABSTRACT
Glycoproteins derived from most retroviruses and from several families of enveloped viruses can form infectious pseudotypes with murine leukemia virus (MLV) and lentiviral core particles, like the MLV envelope glycoproteins (Env) that are incorporated on either virus type. However, coexpression of a given glycoprotein with heterologous core proteins does not always give rise to highly infectious viral particles, and restrictions on pseudotype formation have been reported. To understand the mechanisms that control the recruitment of viral surface glycoproteins on lentiviral and retroviral cores, we exploited the fact that the feline endogenous retrovirus RD114 glycoprotein does not efficiently pseudotype lentiviral cores derived from simian immunodeficiency virus, whereas it is readily incorporated onto MLV particles. Our results indicate that recruitment of glycoproteins by the MLV and lentiviral core proteins occurs in intracellular compartments and not at the cell surface. We found that Env and core protein colocalization in intracytoplasmic vesicles is required for pseudotype formation. By investigating MLV/RD114 Env chimeras, we show that signals in the cytoplasmic tail of either glycoprotein differentially influenced their intracellular localization; that of MLV allows endosomal localization and hence recruitment by both lentiviral and MLV cores. Furthermore, we found that upon membrane binding, MLV core proteins could relocalize Env glycoproteins in late endosomes and allow their incorporation on viral particles. Thus, intracellular colocalization, as well as interactions between Env and core proteins, may influence the recruitment of the glycoprotein onto viral particles and generate infectious pseudotyped viruses.
Receptor (CD155)-Dependent Endocytosis of Poliovirus and Retrograde Axonal Transport of the Endosome
Authors: Ohka Seii , Matsuda Norie , Tohyama Koujiro , Oda Toshiyuki , Morikawa Masato , Kuge Shusuke , Nomoto Akio 
Published: June 2004

ABSTRACT

Poliovirus (PV), when injected intramuscularly into the calf, is incorporated into the sciatic nerve and causes an initial paralysis of the inoculated limb in transgenic mice carrying the human PV receptor (hPVR/CD155) gene. Here, we demonstrated by using an immunoelectron microscope that PV particles exist on vesicle structures in nerve terminals of neuromuscular junctions. We also demonstrated in glutathione
S
-transferase pull-down experiments that the dynein light chain, Tctex-1, interacts directly with the cytoplasmic domain of hPVR. In the axons of differentiated rat PC12 cells transfected with expression vectors for hPVRs, vesicles composed of PV and hPVRα, as well as a mutant hPVRα (hPVRMα) that had a reduced ability to bind Tctex-1, colocalized with Tctex-1. However, vesicles containing PV, dextran, and hPVRα had only retrograde motion, while those containing PV, dextran, and hPVRMα had anterograde or retrograde motion. Topical application of the antimicrotubule agent vinblastine to the sciatic nerve reduced the amount of virus transported from the calf to the spinal cord. These results suggest that direct efficient interaction between the cytoplasmic domain and Tctex-1 is essential for the efficient retrograde transport of PV-containing vesicles along microtubules in vivo.
E1
∧
E4 Protein of Human Papillomavirus Type 16 Associates with Mitochondria
Authors: Raj Kenneth , Berguerand Samuel , Southern Shirley , Doorbar John , Beard Peter 
Published: June 2004

ABSTRACT

The human papillomavirus (HPV) E1
∧
E4 protein is the most abundantly expressed viral protein in HPV-infected epithelia. It possesses diverse activities, including the ability to bind to the cytokeratin network and to DEAD-box proteins, and in some cases induces the collapse of the former. E1
∧
E4 is also able to prevent the progression of cells into mitosis by arresting them in the G
2
phase of the cell cycle. In spite of these intriguing properties, the role of this protein in the life cycle of the virus is not clear. Here we report that after binding to and collapsing the cytokeratin network, the HPV type 16 E1
∧
E4 protein binds to mitochondria. When cytokeratin is not present in the cell, E1
∧
E4 appears associated with mitochondria soon after its synthesis. The leucine cluster within the N-terminal portion of the E1
∧
E4 protein is pivotal in mediating this association. After the initial binding to mitochondria, the E1
∧
E4 protein induces the detachment of mitochondria from microtubules, causing the organelles to form a single large cluster adjacent to the nucleus. This is followed by a severe reduction in the mitochondrial membrane potential and an induction of apoptosis. HPV DNA replication and virion production occur in terminally differentiating cells which are keratin-rich, rigid squamae that exfoliate after completion of the differentiation process. Perturbation of the cytokeratin network and the eventual induction of apoptotic properties are processes that could render these unyielding cells more fragile and ease the exit of newly synthesized HPVs for subsequent rounds of infection.
Small Compounds Targeted to Subunit Interfaces Arrest Maturation in a Nonenveloped, Icosahedral Animal Virus
Authors: Lee Kelly K. , Tang Jinghua , Taylor Derek , Bothner Brian , Johnson John E. 
Published: June 2004

ABSTRACT

Nudaurelia
ω
capensis
virus (NωV) capsids were previously characterized in two morphological forms, a T=4, 485-Å-diameter round particle with large pores and a tightly sealed 395-Å icosahedrally shaped particle with the same quasi-symmetric surface lattice. The large particle converts to the smaller particle when the pH is lowered from 7.6 to 5, and this activates an autocatalytic cleavage of the viral subunit at residue 570. Here we report that both 1-anilino-8 naphthalene sulfonate (ANS) and the covalent attachment of the thiol-reactive fluorophore, maleimide-ANS (MIANS), inhibit the structural transition and proteolysis at the lower pH. When ANS is exhaustively washed from the particles, the maturation proceeds normally; however, MIANS-modified particles are still inhibited after the same washing treatment, indicating that covalent attachment targets MIANS to a critical location for inhibition. Characterization of the low-pH MIANS product by electron cryo-microscopy (cryo-EM) and image reconstruction demonstrated a morphology intermediate between the two forms previously characterized. A pseudoatomic model of the intermediate configuration was generated by rigid body refinement of the X-ray structure of the subunits (previously determined in the assembled capsid) into the cryo-EM density, allowing a quantitative description of the inhibited intermediate and a hypothesis for the mechanism of the inhibition.
Gene Transduction and Cell Entry Pathway of Fiber-Modified Adenovirus Type 5 Vectors Carrying Novel Endocytic Peptide Ligands Selected on Human Tracheal Glandular Cells
Authors: Gaden Florence , Franqueville Laure , Magnusson Maria K. , Hong Saw See , Merten Marc D. , Lindholm Leif , Boulanger Pierre 
Published: June 2004

ABSTRACT
Monolayers of cystic fibrosis transmembrane conductance regulator (CFTR)-deficient human tracheal glandular cells (CF-KM4) were subjected to phage biopanning, and cell-internalized phages were isolated and sequenced, in order to identify CF-KM4-specific peptide ligands that would confer upon adenovirus type 5 (Ad5) vector a novel cell target specificity and/or higher efficiency of gene delivery into airway cells of patients with cystic fibrosis (CF). Three different ligands, corresponding to prototypes of the most represented families of phagotopes recovered from intracellular phages, were designed and individually inserted into Ad5-green fluorescent protein (GFP) (AdGFP) vectors at the extremities of short fiber shafts (seven repeats [R7]) terminated by scissile knobs. Only one vector, carrying the decapeptide GHPRQMSHVY (abbreviated as QM10), showed an enhanced gene transduction of CF-KM4 cells compared to control nonliganded vector with fibers of the same length (AdGFP-R7-knob). The enhancement in gene transfer efficiency was not specific to CF-KM4 cells but was observed in other mammalian cell lines tested. The QM10-liganded vector was referred to as AdGFP-QM10-knob in its knobbed version and as AdGFP-QM10 in its proteolytically deknobbed version. AdGFP-QM10 was found to transduce cells with a higher efficiency than its knob-bearing version, AdGFP-QM10-knob. Consistent with this, competition experiments indicated that the presence of knob domains was not an absolute requirement for cell attachment of the QM10-liganded vector and that the knobless AdGFP-QM10 used alternative cell-binding domains on its capsid, including penton base capsomer, via a site(s) different from its RGD motifs. The QM10-mediated effect on gene transduction seemed to take place at the step of endocytosis in both quantitative and qualitative manners. Virions of AdGFP-QM10 were endocytosed in higher numbers than virions of the control vector and were directed to a compartment different from the early endosomes targeted by members of species C Ad. AdGFP-QM10 was found to accumulate in late endosomal and low-pH compartments, suggesting that QM10 acted as an endocytic ligand of the lysosomal pathway. These results validated the concept of detargeting and retargeting Ad vectors via our deknobbing system and redirecting Ad vectors to an alternative endocytic pathway via a peptide ligand inserted in the fiber shaft domain.
Influence of N-Glycans on Processing and Biological Activity of the Nipah Virus Fusion Protein
Authors: Moll Markus , Kaufmann Andreas , Maisner Andrea 
Published: June 2004

ABSTRACT

Nipah virus
(NiV), a new member of the
Paramyxoviridae
, codes for a fusion (F) protein with five potential N-glycosylation sites. Because glycans are known to be important structural components affecting the conformation and function of viral glycoproteins, we analyzed the effect of the deletion of N-linked oligosaccharides on cell surface transport, proteolytic cleavage, and the biological activity of the NiV F protein. Each of the five potential glycosylation sites was removed either individually or in combination, revealing that four sites are actually utilized (g2 and g3 in the F
2
subunit and g4 and g5 in the F
1
subunit). While the removal of g2 and/or g3 had no or little effect on cleavage, surface transport, and fusion activity, the elimination of g4 or g5 reduced the surface expression by more than 80%. Similar to a mutant lacking all N-glycans, g4 deletion mutants in which the potential glycosylation site was destroyed by introducing a glycine residue were neither cleaved nor transported to the cell surface and consequently were not able to mediate cell-to-cell fusion. This finding indicates that in the absence of g4, the amino acid sequence around position 414 is important for folding and transport.
Inhibition of Streptokinase‐Induced, Antibody‐Mediated Platelet Aggregation with Tirofiban After Exposure to Streptokinase or Streptococcal Infection
Authors: Courval Maryse , Palisaitis Donald A. , Diodati Jean G. , Lesperance Bernard , Pharand Chantal 
Published: June 2004

Study Objective. To evaluate the effect of tirofiban (a glycoprotein IIb‐IIIa inhibitor) in preventing streptokinase‐induced, antibody‐mediated platelet aggregation after administration of streptokinase or development of a streptococcal infection.Design. Prospective analysis.Setting. Research center of a Canadian hospital.Participants. Forty‐five healthy volunteers, 45 patients who had received streptokinase within the past 3 years, and 13 patients who had a severe streptococcal infection also within the past 3 years.Intervention. Blood samples were drawn to measure the extent of inhibition of streptokinase‐induced, antibody‐mediated platelet activation and aggregation by tirofiban.Measurements and Main Results. Platelet aggregation was measured by using a turbidimetric method. The extent of inhibition by tirofiban was measured by incubating tirofiban for 2 minutes before adding streptokinase 5000 U/ml. Also, tirofiban was added 2 minutes before adding adenosine 5′‐diphosphate (ADP) 2 μM/L into the last tube as a comparison. Streptokinase‐induced, antibody‐mediated platelet aggregation was observed in 10 (22%) of the 45 patients treated with streptokinase, in 3 (23%) of the 13 patients with streptococcal infection, and in none of the 45 healthy volunteers. Tirofiban inhibited streptokinase‐induced, antibody‐mediated platelet aggregation by 89 ± 14% (p<0.001). Similarly, ADP‐induced platelet aggregation was inhibited by 92 ± 6% (p<0.001) with tirofiban.Conclusion. Streptokinase‐induced, antibody‐mediated platelet aggregation occurred in 13 (22%) of 58 patients who received streptokinase or were exposed to a streptococcal infection in the past 3 years. Such patients may not benefit from streptokinase therapy. In these patients, tirofiban significantly decreased the extent of antistreptokinase antibody–mediated platelet aggregation. Hence, patients undergoing streptokinase therapy may benefit from tirofiban as adjunctive therapy.
Tobramycin Pharmacokinetics in Children with Febrile Neutropenia Undergoing Stem Cell Transplantation: Once‐Daily versus Thrice‐Daily Administration
Authors: Dupuis L. Lee , Sung Lillian , Taylor Tracey , Abdolell Mohamed , Allen Upton , Doyle John , Taddio Anna 
Published: June 2004

Study Objectives. To describe the pharmacokinetic disposition of tobramycin in children undergoing stem cell transplantation (SCT) after intravenous administration either every 24 hours or every 8 hours, and to use this information to create initial dosing guidelines for administration every 24 hours in this patient population.Design. Pharmacokinetic analysis of a randomized controlled trial.Setting. The Hospital for Sick Children, Toronto, Ontario, Canada.Patients. Sixty children (< 18 yrs) with febrile neutropenia undergoing stem cell transplantation.Intervention. Patients were randomized to receive intravenous tobramycin either every 24 hours (29 patients) or every 8 hours (31 patients). Initially, they received either 2.5 mg/kg/dose every 8 hours or weight‐based doses by age group (< 5 yrs, 9 mg/kg/dose; 5 to < 12 yrs, 8 mg/kg/dose; ≥ 12 yrs, 7 mg/kg/dose) every 24 hours.Measurements and Main Results. Serum tobramycin concentrations were obtained at 2 and 8 hours after the first dose. Initial guidelines for dosing every 24 hours were derived using the parameters from all patients to achieve a maximum serum concentration (Cmax) of 20–22.5 mg/L and a drug‐free interval (time during dosing interval when the tobramycin concentration was < 1 mg/L) of at least 4 hours. After the first tobramycin dose, the elimination rate constant (kel) and volume of distribution (Vd) observed in the every‐8‐hour group (23 patients) were 0.34 ± 0.09 hours−1 and 0.48 ± 0.21 L/kg, respectively. The kel and Vd in the every‐24‐hour group (22 patients) were 0.43 ± 0.12 hr−1 and 0.43 ± 0.26 L/kg, respectively. Tobramycin Vd varied with age. Initial doses of tobramycin every 24 hours recommended to achieve the target parameters are 10 mg/kg/dose for patients aged 6 months to less than 9 years, 8 mg/kg/dose for those aged 9 to less than 12 years, and 6 mg/kg/dose for those aged 12 years or older.Conclusion. Children undergoing SCT who receive tobramycin every 24 hours should receive an initial dose based on age. Further validation of the proposed dosing guidelines is required.
Statins and Liver Toxicity: A Meta‐Analysis
Authors: de Denus Simon , Spinler Sarah A. , Miller Kristin , Peterson Andrew M. 
Published: June 2004

Study Objective. To assess the risk of liver function test (LFT) abnormalities with the use of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase inhibitors (statins) for the treatment of hyperlipidemia.Design. Meta‐analysis of randomized, placebo‐controlled trials of statins used for the treatment of hyperlipidemia or for primary or secondary prevention of cardiovascular disease.Setting. University research center.Patients. A total of 49,275 patients from 13 trials.Intervention. A literature search of published clinical trials was performed in MEDLINE (January 1966–March 2003) and the Cochrane Controlled Trials Registry (first quarter 2003). Studies also were identified from the references of the trials and of published systematic reviews.Measurements and Main Results. For a trial to be included in the meta‐analysis, its duration of follow‐up had to be at least 48 weeks and the trial had to include at least 400 patients, with at least 200 treated with a statin. Trials conducted in transplant recipients were excluded. The proportion of patients having LFT abnormalities was low in both groups (statins 1.14% vs placebo 1.05%, odds ratio [OR] 1.26, 95% confidence interval [CI] 0.99–1.62, p=0.07). Only fluvastatin was associated with a significant increase in the odds of having LFT abnormalities (fluvastatin 1.13% vs placebo 0.29%, OR 3.54, 95% CI 1.1–11.6, p=0.04) compared with placebo, although this finding was based on only two trials.Conclusions. Our results support previous observations that pravastatin, lovastatin, and simvastatin at low‐to‐moderate doses are not associated with a significant risk of LFT abnormalities. Additional data are required to determine whether other statins have a similar safety profile.
A Disease Management Protocol for Outpatient Perioperative Bridge Therapy with Enoxaparin in Patients Requiring Temporary Interruption of Long‐Term Oral Anticoagulation
Authors: Spyropoulos Alex C. , Jenkins Patti , Bornikova Larissa 
Published: June 2004

Study Objective. Traditional perioperative bridge therapy for patients receiving long‐term oral anticoagulation involves weight‐adjusted intravenous unfractionated heparin (UFH) in the perioperative period during temporary discontinuation of the oral anticoagulant. We sought to determine whether an alternate strategy of outpatient‐based perioperative disease management with low‐molecular‐weight heparin (LMWH) as bridge therapy provides the potential for cost savings.Design. Retrospective review of all clinic notes from an anticoagulation clinic.Setting. An integrated, staff‐model health maintenance organization.Patients. Patients receiving long‐term warfarin therapy from January 1998–March 2002 who received perioperative bridge therapy with the LMWH enoxaparin 1 mg/kg twice/day subcutaneously.Measurements and Main Results. A total of 126 bridge therapy encounters in 84 patients receiving LMWH as perioperative bridge therapy were identified, with 48 of those encounters involving patients with at least one mechanical heart valve. A total of 1108 hospital bed days were saved. Based on 1996 cost estimates, the total approximate cost savings for the 4.25 years of the outpatient bridge therapy program was $903,020. No thrombotic events were reported. Three major hemorrhagic events that required discontinuation of LMWH were reported.Conclusion. Outpatient‐based disease management protocols and the LMWH enoxaparin as bridge therapy during temporary discontinuation of warfarin for an elective surgical procedure resulted in cost savings of approximately $212,475/year in an integrated health maintenance organization. In addition, this strategy appears both safe and effective.
Modeling of nanoparticles formation by mixing of two reactive microemulsions
Authors: Ramesh Kumar A. , Hota G. , Mehra A. , Khilar Kartic C. 
Published: June 2004

AbstractA stochastic population balance model for the formation of nanoparticles, involving mixing of two micellized aqueous solutions containing the individual reactants, respectively, has been developed to study the effects of various parameters that influence the formation process of nanoparticles. Population balance equations have been formulated assuming a cooperative mode of intermicellar exchange in an attempt to explore the largest possible particles that can form in a given system. The proposed model essentially divides the entire population of micelles into different categories and formulates the equations describing the rate of change of the probabilities of different states of the micelles in each category. The effect of parameters, such as nucleation rate, intermicellar exchange rate, critical nucleation number, and concentration of the reactants on the particle sizes that can be obtained, has been investigated. The model predictions show a reasonable qualitative agreement with experimental data. © 2004 American Institute of Chemical Engineers AIChE J, 50:1556–1567, 2004
Effect of halogen in high‐density oxygen plasmas on photoresist trimming
Authors: Sin Chian‐Yuh , Chen Bing‐Hung , Loh W. L. , Yu J. , Yelehanka P. , See A. , Chan L. 
Published: June 2004

AbstractEffects of halogens, CF4, Cl2, or HBr, on the photoresist trimming in high‐density oxygen plasmas for sub‐0.1‐μm device fabrication were studied in an inductively coupled plasma (ICP) etcher. The trim rates were measured as a function of halogen gas percentages. The activation energy and the resulting resist profiles were investigated as well, showing that the CF4/O2gives the highest trim rate, followed by HBr/O2and then Cl2/O2at the same amount of additive gas in the mixture. Effects of different plasma chemistry on the chemical constituents of the resist sidewall films were also examined with the angle‐resolved X‐ray photoelectron spectroscopy (XPS). XPS analysis reveals that all halogen gases are useful for resist sidewall protection because of the passivation by the halogen‐containing polymer. The effects of halogen addition include the reaction enhancement, reaction‐site competition between oxygen and halogen, changes in the plasma gas chemistry, and the resist passivation. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1578–1588, 2004
Decomposition of monochlorobiphenyl isomers in supercritical water in the presence of methanol
Authors: Anitescu Gheorghe , Tavlarides Lawrence L. , Munteanu Valentin 
Published: June 2004

AbstractComprehensive studies of monochlorobiphenyl (MCB) decomposition in supercritical water in the presence of methanol and other cosolvents, both with and without oxygen, are being conducted to understand the reaction kinetics and pathways of individual PCB isomers and to determine the structure–reactivity relationships. In the present study the disappearance rate of MCBs, delivered in an isothermal plug‐flow tubular reactor as methanolic solutions, is investigated at 25 MPa and temperatures of 673, 723, and 773 K. Experiments are conducted at nominal MCB feed concentrations of 1–100 μmol/L (reaction conditions) using MCB/MeOH and H2O2/H2O solutions (1–3 g/L and 0–10 wt. %, respectively). Molar conversions of these isomers vary from 3% (2‐CB, 773 K, 2 s) to 30% (4‐CB, 773 K, 46 s) without oxygen (SCWT) and from 1% (2‐CB, 673 K, 3.8 s) to 97% (4‐CB, 773 K, 24.5 s) with oxygen (SCWO). For SCWT the overall conversion follows apparent first order, whereas for SCWO the conversion is second order. The regressed data lead to Arrhenius parameters of frequency factor and activation energy with values of 1020.5–1021.3 s−1 and 320–331 kJ/mol for SCWT and 1024.1–1024.8 s−1 (mol/L)−1 and 281–292 kJ/mol for SCWO, respectively. The reactivity of the MCB isomers increases in the order 2‐MCB < 3‐MCB < 4‐MCB. The positively identified reaction products by GC‐MSD and GC‐FID/ECD/TCD analyses are mainly biphenyl, open‐ring biphenyl compounds such as acetophenone and benzaldehydes, and mineral products (CO, CO2, and HCl). More studies are in progress regarding the role of the second solvent on reaction rates and reaction mechanisms and pathways. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1536–1544, 2004