bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Immunodeficiency Virus Type 1 Replication in the Absence of Integrase-Mediated DNA Recombination: Definition of Permissive and Nonpermissive T-Cell Lines
Authors: Nakajima Noriko , Lu Richard , Engelman Alan
Published: July 2002

Functional retroviral integrase protein is thought to be essential for productive viral replication. Yet, previous studies differed on the extent to which integrase mutant viruses expressed human immunodeficiency virus type 1 (HIV-1) genes from unintegrated DNA. Although one reason for this difference was that class II integrase mutations pleiotropically affected the viral life cycle, another reason apparently depended on the identity of the infected cell. Here, we analyzed integrase mutant viral infectivities in a variety of cell types. Single-round infectivity of class I integration-specific mutant HIV-1 ranged from <0.03 to 0.3% of that of the wild type (WT) across four different T-cell lines. Based on this approximately 10-fold influence of cell type on mutant gene expression, we examined class I and class II mutant replication kinetics in seven different cell lines and two primary cell types. Unexpectedly, some cell lines supported productive class I mutant viral replication under conditions that restricted class II mutant growth. Cells were defined as permissive, semipermissive, or nonpermissive based on their ability to support the continual passage of class I integration-defective HIV-1. Mutant infectivity in semipermissive and permissive cells as quantified by 50% tissue culture infectious doses, however, was only 0.0006 to 0.005% of that of WT. Since the frequencies of mutant DNA recombination in these lines ranged from 0.023 to <0.093% of the WT, we conclude that productive replication in the absence of integrase function most likely required the illegitimate integration of HIV-1 into host chromosomes by cellular DNA recombination enzymes.
Use of Whole Genome Sequence Data To Infer Baculovirus Phylogeny
Authors: Herniou Elisabeth A. , Luque Teresa , Chen Xinwen , Vlak Just M. , Winstanley Doreen , Cory Jennifer S. , O'Reilly David R.
Published: July 2002

Several phylogenetic methods based on whole genome sequence data were evaluated using data from nine complete baculovirus genomes. The utility of three independent character sets was assessed. The first data set comprised the sequences of the 63 genes common to these viruses. The second set of characters was based on gene order, and phylogenies were inferred using both breakpoint distance analysis and a novel method developed here, termed neighbor pair analysis. The third set recorded gene content by scoring gene presence or absence in each genome. All three data sets yielded phylogenies supporting the separation of the
Nucleopolyhedrovirus
(NPV) and
Granulovirus
(GV) genera, the division of the NPVs into groups I and II, and species relationships within group I NPVs. Generation of phylogenies based on the combined sequences of all 63 shared genes proved to be the most effective approach to resolving the relationships among the group II NPVs and the GVs. The history of gene acquisitions and losses that have accompanied baculovirus diversification was visualized by mapping the gene content data onto the phylogenetic tree. This analysis highlighted the fluid nature of baculovirus genomes, with evidence of frequent genome rearrangements and multiple gene content changes during their evolution. Of more than 416 genes identified in the genomes analyzed, only 63 are present in all nine genomes, and 200 genes are found only in a single genome. Despite this fluidity, the whole genome-based methods we describe are sufficiently powerful to recover the underlying phylogeny of the viruses.
Reovirus Infection Activates JNK and the JNK-Dependent Transcription Factor c-Jun
Authors: Clarke Penny , Meintzer Suzanne M. , Widmann Christian , Johnson Gary L. , Tyler Kenneth L.
Published: July 2002

Viral infection often perturbs host cell signaling pathways including those involving mitogen-activated protein kinases (MAPKs). We now show that reovirus infection results in the selective activation of c-Jun N-terminal kinase (JNK). Reovirus-induced JNK activation is associated with an increase in the phosphorylation of the JNK-dependent transcription factor c-Jun. Reovirus serotype 3 prototype strains Abney (T3A) and Dearing (T3D) induce significantly more JNK activation and c-Jun phosphorylation than does the serotype 1 prototypic strain Lang (T1L). T3D and T3A also induce more apoptosis in infected cells than T1L, and there was a significant correlation between the ability of these viruses to phosphorylate c-Jun and induce apoptosis. However, reovirus-induced apoptosis, but not reovirus-induced c-Jun phosphorylation, is inhibited by blocking TRAIL/receptor binding, suggesting that apoptosis and c-Jun phosphorylation involve parallel rather than identical pathways. Strain-specific differences in JNK activation are determined by the reovirus S1 and M2 gene segments, which encode viral outer capsid proteins (ς1 and μ1c) involved in receptor binding and host cell membrane penetration. These same gene segments also determine differences in the capacity of reovirus strains to induce apoptosis, and again a significant correlation between the capacity of T1L × T3D reassortant reoviruses to both activate JNK and phosphorylate c-Jun and to induce apoptosis was shown. The extracellular signal-related kinase (ERK) is also activated in a strain-specific manner following reovirus infection. Unlike JNK activation, ERK activation could not be mapped to specific reovirus gene segments, suggesting that ERK activation and JNK activation are triggered by different events during virus-host cell interaction.
Analysis of Total Human Immunodeficiency Virus (HIV)-Specific CD4
+
and CD8
+
T-Cell Responses: Relationship to Viral Load in Untreated HIV Infection
Authors: Betts Michael R. , Ambrozak David R. , Douek Daniel C. , Bonhoeffer Sebastian , Brenchley Jason M. , Casazza Joseph P. , Koup Richard A. , Picker Louis J.
Published: July 2002

Human immunodeficiency virus (HIV)-specific T-cell responses are thought to play a key role in viral load decline during primary infection and in determining the subsequent viral load set point. The requirements for this effect are unknown, partly because comprehensive analysis of total HIV-specific CD4
+
and CD8
+
T-cell responses to all HIV-encoded epitopes has not been accomplished. To assess these responses, we used cytokine flow cytometry and overlapping peptide pools encompassing all products of the HIV-1 genome to study total HIV-specific T-cell responses in 23 highly active antiretroviral therapy naı̈ve HIV-infected patients. HIV-specific CD8
+
T-cell responses were detectable in all patients, ranging between 1.6 and 18.4% of total CD8
+
T cells. HIV-specific CD4
+
T-cell responses were present in 21 of 23 patients, although the responses were lower (0.2 to 2.94%). Contrary to previous reports, a positive correlation was identified between the plasma viral load and the total HIV-, Env-, and Nef-specific CD8
+
T-cell frequency. No correlation was found either between viral load and total or Gag-specific CD4
+
T-cell response or between the frequency of HIV-specific CD4
+
and CD8
+
T cells. These results suggest that overall frequencies of HIV-specific T cells are not the sole determinant of immune-mediated protection in HIV-infection.
Role of Calcium in Protein Folding and Function of Tva, the Receptor of Subgroup A Avian Sarcoma and Leukosis Virus
Authors: Wang Qing-Yin , Dolmer Klavs , Huang Wen , Gettins Peter G. W. , Rong Lijun
Published: July 2002

Tva is the cellular receptor for subgroup A avian sarcoma and leukosis virus (ASLV-A). The viral receptor function of Tva is determined by a 40-residue cysteine-rich motif called the LDL-A module. In this study, we expressed and purified the wild-type (wt) Tva LDL-A module as well as several mutants and examined their in vitro folding properties. We found that, as for other LDL-A modules, correct folding and structure of the Tva LDL-A module is Ca
2+
dependent. When calcium was present during in vitro protein folding, the wt module was eluted as a single peak by reverse-phase high-pressure liquid chromatography. Furthermore, two-dimensional nuclear magnetic resonance (NMR) spectroscopy gave well-dispersed spectra in the presence of calcium. In contrast, the same protein folded in vitro in the absence of calcium was eluted as multiple broad peaks and gave a poorly dispersed NMR spectrum in the presence of calcium. The calcium affinity (

K
d

) of the Tva LDL-A module, determined by isothermal titration calorimetry, is approximately 40 μM. Characterization of several Tva mutants provided further evidence that calcium is important in protein folding and function of Tva. Mutations of the Ca
2+
-binding residues (D46A and E47A) completely abrogated the Ca
2+
-binding ability of Tva, and the proteins were not correctly folded. Interestingly, mutations of two non-calcium-binding residues (W48A and L34A) also exerted adverse effect on Ca
2+
-dependent folding, albeit to a much less extent. Our results provide new insights regarding the structure and function of Tva in ASLV-A entry.
Reversal of Human Immunodeficiency Virus Type 1 IIIB to a Neutralization-Resistant Phenotype in an Accidentally Infected Laboratory Worker with a Progressive Clinical Course
Authors: Beaumont Tim , van Nuenen Ad , Broersen Silvia , Blattner William A. , Lukashov Vladimir V. , Schuitemaker Hanneke
Published: July 2002

The role of humoral immunity in controlling human immunodeficiency virus type 1 (HIV-1) is still controversial. The resistance of primary HIV-1 variants to neutralization by antibodies, sera from HIV-1-infected patients, and soluble CD4 protein has been suggested to be a prerequisite for the virus to establish persistence in vivo. To further test this hypothesis, we studied the neutralization sensitivity of two IIIB/LAV variants that were isolated from a laboratory worker who accidentally was infected with the T-cell-line-adapted neutralization-sensitive IIIB isolate. Compared to the original virus in the inoculum, the reisolated viruses showed an increased resistance to neutralization over time. The ratio of nonsynonymous to synonymous nucleotide substitutions in the envelope gene pointed to strong positive selection. The emergence of neutralization-resistant HIV preceded disease development in this laboratory worker. Our results imply that the neutralization resistance of primary HIV may indeed be considered an escape mechanism from humoral immune control.
Direct In Vitro Binding of Full-Length Human Immunodeficiency Virus Type 1 Nef Protein to CD4 Cytoplasmic Domain
Authors: Preusser Andrea , Briese Lars , Baur Andreas S. , Willbold Dieter
Published: July 2002

The Nef protein of the simian and human immunodeficiency viruses is known to directly bind and downregulate the CD4 receptor. Although the molecular mechanism is well understood, direct binding of Nef and CD4 is difficult to demonstrate and is believed to be of low affinity. Applying nuclear magnetic resonance and fluorescence spectroscopy, we biophysically reevaluated the CD4-Nef complex and found the dissociation constant to be in the submicromolar range. We conclude that additional, so far disregarded residues in the N terminus of Nef are important for interaction with CD4.
West Nile Virus Recombinant DNA Vaccine Protects Mouse and Horse from Virus Challenge and Expresses In Vitro a Noninfectious Recombinant Antigen That Can Be Used in Enzyme-Linked Immunosorbent Assays
Authors: Davis Brent S. , Chang Gwong-Jen J. , Cropp Bruce , Roehrig John T. , Martin Denise A. , Mitchell Carl J. , Bowen Richard , Bunning Michel L.
Published: July 2002

Introduction of West Nile (WN) virus into the United States in 1999 created major human and animal health concerns. Currently, no human or veterinary vaccine is available to prevent WN viral infection, and mosquito control is the only practical strategy to combat the spread of disease. Starting with a previously designed eukaryotic expression vector, we constructed a recombinant plasmid (pCBWN) that expressed the WN virus prM and E proteins. A single intramuscular injection of pCBWN DNA induced protective immunity, preventing WN virus infection in mice and horses. Recombinant plasmid-transformed COS-1 cells expressed and secreted high levels of WN virus prM and E proteins into the culture medium. The medium was treated with polyethylene glycol to concentrate proteins. The resultant, containing high-titered recombinant WN virus antigen, proved to be an excellent alternative to the more traditional suckling-mouse brain WN virus antigen used in the immunoglobulin M (IgM) antibody-capture and indirect IgG enzyme-linked immunosorbent assays. This recombinant antigen has great potential to become the antigen of choice and will facilitate the standardization of reagents and implementation of WN virus surveillance in the United States and elsewhere.
The LD78β Isoform of MIP-1α Is the Most Potent CC-Chemokine in Inhibiting CCR5-Dependent Human Immunodeficiency Virus Type 1 Replication in Human Macrophages
Authors: Aquaro Stefano , Menten Patricia , Struyf Sofie , Proost Paul , Van Damme Jo , De Clercq Erik , Schols Dominique
Published: July 2002

The CC-chemokines RANTES, macrophage inflammatory protein 1α (MIP-1α), and MIP-1β are natural ligands for the CC-chemokine receptor CCR5. MIP-1α, also known as LD78α, has an isoform, LD78β, which was identified as the product of a nonallelic gene. The two isoforms differ in only 3 amino acids. LD78β was recently reported to be a much more potent CCR5 agonist than LD78α and RANTES in inducing intracellular Ca2+signaling and chemotaxis. CCR5 is expressed by human monocytes/macrophages (M/M) and represents an important coreceptor for macrophage-tropic, CCR5-using (R5) human immunodeficiency virus type 1 (HIV-1) strains to infect the cells. We compared the antiviral activities of LD78β and the other CC-chemokines in M/M. LD78β at 100 ng/ml almost completely blocked HIV-1 replication, while at the same concentration LD78α had only weak antiviral activity. Moreover, when HIV-1 infection in M/M was monitored by a flow cytometric analysis using p24 antigen intracellular staining, LD78β proved to be the most antivirally active of the chemokines. RANTES, once described as the most potent chemokine in inhibiting R5 HIV-1 infection, was found to be considerably less active than LD78β. LD78β strongly downregulated CCR5 expression in M/M, thereby explaining its potent antiviral activity.
Envelope Glycoprotein Cytoplasmic Domains from Diverse Lentiviruses Interact with the Prenylated Rab Acceptor
Authors: Evans David T. , Tillman Karl C. , Desrosiers Ronald C.
Published: July 2002

Lentivirus envelope glycoproteins have unusually long cytoplasmic domains compared to those of other retroviruses. To identify cellular binding partners of the simian immunodeficiency virus (SIV) envelope transmembrane protein (gp41) cytoplasmic domain (CD), we performed a yeast two-hybrid screen of a phytohemagglutinin-activated human T-cell cDNA library with the SIV gp41 CD. The majority of positive clones (50 of 54) encoded the prenylated Rab acceptor (PRA1). PRA1 is a 21-kDa protein associated with Golgi membranes that binds to prenylated Rab proteins in their GTP-bound state. While the cellular function of PRA1 is presently unknown, this protein appears to participate in intracellular vesicular trafficking, based on its cellular localization and ability to bind multiple members of the Rab protein family. Mammalian two-hybrid assays confirmed the interaction between the SIV gp41 CD and PRA1. Furthermore, gp41 sequences important for PRA1 binding were mapped to a central leucine-rich, amphipathic α-helix in the SIV gp41 cytoplasmic tail. Although the human immunodeficiency virus (HIV-1) gp41 CD failed to interact with PRA1 in the yeast two-hybrid system, its interaction with PRA1 was significantly better than that of the SIV gp41 CD in mammalian two-hybrid assays. Interestingly, PRA1 also interacted with the Env CDs of HIV-2, bovine immunodeficiency virus, equine infectious anemia virus, and feline immunodeficiency virus. Thus, PRA1 associates with envelope glycoproteins from widely divergent lentiviruses.
Human Immunodeficiency Virus Type 1 Uses Lipid Raft-Colocalized CD4 and Chemokine Receptors for Productive Entry into CD4
+
T Cells
Authors: Popik Waldemar , Alce Timothy M. , Au Wei-Chun
Published: July 2002

In this report, we describe a crucial role of lipid raft-colocalized receptors in the entry of human immunodeficiency virus type 1 (HIV-1) into CD4
+
T cells. We show that biochemically isolated detergent-resistant fractions have characteristics of lipid rafts. Lipid raft integrity was required for productive HIV-1 entry as determined by (i) semiquantitative PCR analysis and (ii) single-cycle infectivity assay using HIV-1 expressing the luciferase reporter gene and pseudotyped with HIV-1 HXB2 envelope or vesicular stomatitis virus envelope glycoprotein (VSV-G). Depletion of plasma membrane cholesterol with
methyl
-β-cyclodextrin (MβCD) relocalized raft-resident markers to a nonraft environment but did not significantly change the surface expression of HIV-1 receptors. MβCD treatment inhibited productive infection of HIV-1 by 95% as determined by luciferase activity in cells infected with HXB2 envelope-pseudotyped virus. In contrast, infection with VSV-G-pseudotyped virus, which enters the cells through an endocytic pathway, was not suppressed. Biochemical fractionation and confocal imaging of HIV-1 receptor distribution in live cells demonstrated that CD4, CCR5, and CXCR4 colocalized with raft-resident markers, ganglioside GM1, and glycosylphosphatidylinositol-anchored CD48. While confocal microscopy analysis revealed that HIV-1 receptors localized most likely to the same lipid microdomains, sucrose gradient analysis of the receptor localization showed that, in contrast to CD4 and CCR5, CXCR4 was associated preferentially with the nonraft membrane fraction. The binding of HIV-1 envelope gp120 to lipid rafts in the presence, but not in the absence, of cholesterol strongly supports our hypothesis that raft-colocalized receptors are directly involved in virus entry. Dramatic changes in lipid raft and HIV-1 receptor redistribution were observed upon binding of HIV-1 NL4-3 to PM1 T cells. Colocalization of CCR5 with GM1 and gp120 upon engagement of CD4 and CXCR4 by HIV-1 further supports our observation that HIV-1 receptors localize to the same lipid rafts in PM1 T cells.
Functional Evaluation of DC-SIGN Monoclonal Antibodies Reveals DC-SIGN Interactions with ICAM-3 Do Not Promote Human Immunodeficiency Virus Type 1 Transmission
Authors: Wu Li , Martin Thomas D. , Vazeux Rosemay , Unutmaz Derya , KewalRamani Vineet N.
Published: July 2002

DC-SIGN, a type II membrane-spanning C-type lectin that is expressed on the surface of dendritic cells (DC), captures and promotes human and simian immunodeficiency virus (HIV and SIV) infection of CD4
+
T cells in
trans
. To better understand the mechanism of DC-SIGN-mediated virus transmission, we generated and functionally evaluated a panel of seven monoclonal antibodies (MAbs) against DC-SIGN family molecules. Six of the MAbs reacted with myeloid-lineage DC, whereas one MAb preferentially bound DC-SIGNR/L-SIGN, a homolog of DC-SIGN. Characterization of hematopoietic cells also revealed that stimulation of monocytes with interleukin-4 (IL-4) or IL-13 was sufficient to induce expression of DC-SIGN. All DC-SIGN-reactive MAbs competed with intercellular adhesion molecule 3 (ICAM-3) for adhesion to DC-SIGN and blocked HIV-1 transmission to T cells that was mediated by THP-1 cells expressing DC-SIGN. Similar but less efficient MAb blocking of DC-mediated HIV-1 transmission was observed, indicating that HIV-1 transmission to target cells via DC may not be dependent solely on DC-SIGN. Attempts to neutralize DC-SIGN capture and transmission of HIV-1 with soluble ICAM-3 prophylaxis were limited in success, with a maximal inhibition of 60%. In addition, disrupting DC-SIGN/ICAM-3 interactions between cells with MAbs did not impair DC-SIGN-mediated HIV-1 transmission. Finally, forced expression of ICAM-3 on target cells did not increase their susceptibility to HIV-1 transmission mediated by DC-SIGN. While these findings do not discount the role of intercellular contact in facilitating HIV-1 transmission, our in vitro data indicate that DC-SIGN interactions with ICAM-3 do not promote DC-SIGN-mediated virus transmission.
C-Type Lectins DC-SIGN and L-SIGN Mediate Cellular Entry by Ebola Virus in
cis
and in
trans
Authors: Alvarez Carmen P. , Lasala Fátima , Carrillo Jaime , Muñiz Oscar , Corbí Angel L. , Delgado Rafael
Published: July 2002

Ebola virus is a highly lethal pathogen responsible for several outbreaks of hemorrhagic fever. Here we show that the primate lentiviral binding C-type lectins DC-SIGN and L-SIGN act as cofactors for cellular entry by Ebola virus. Furthermore, DC-SIGN on the surface of dendritic cells is able to function as a
trans
receptor, binding Ebola virus-pseudotyped lentiviral particles and transmitting infection to susceptible cells. Our data underscore a role for DC-SIGN and L-SIGN in the infective process and pathogenicity of Ebola virus infection.
Induction of Mucosal Protection against Primary, Heterologous Simian Immunodeficiency Virus by a DNA Vaccine
Authors: Fuller Deborah Heydenburg , Rajakumar Premeela A. , Wilson Lawrence A. , Trichel Anita M. , Fuller James T. , Shipley Tim , Wu Mary S. , Weis Kathleen , Rinaldo Charles R. , Haynes Joel R. , Murphey-Corb Michael
Published: July 2002

An effective vaccine against human immunodeficiency virus (HIV) should protect against mucosal transmission of genetically divergent isolates. As a safe alternative to live attenuated vaccines, the immunogenicity and protective efficacy of a DNA vaccine containing simian immunodeficiency virus (SIV) strain 17E-Fr (SIV/17E-Fr)gag-pol-envwas analyzed in rhesus macaques. Significant levels of cytotoxic T lymphocytes (CTL), but low to undetectable serum antibody responses, were observed following multiple immunizations. SIV-specific mucosal antibodies and CTL were also detected in rectal washes and gut-associated lymphoid tissues, respectively. Vaccinated and naive control monkeys were challenged intrarectally with SIV strain DeltaB670 (SIV/DeltaB670), a primary isolate whoseenvis 15% dissimilar to that of the vaccine strain. Four of seven vaccinees were protected from infection as determined by the inability to identify viral RNA or DNA sequences in the peripheral blood and the absence of anamnestic antibody responses postchallenge. This is the first report of mucosal protection against a primary pathogenic, heterologous isolate of SIV by using a commercially viable vaccine approach. These results support further development of a DNA vaccine for protection against HIV.
Adeno-Associated Virus Capsids Displaying Immunoglobulin-Binding Domains Permit Antibody-Mediated Vector Retargeting to Specific Cell Surface Receptors
Authors: Ried Martin U. , Girod Anne , Leike Kristin , Büning Hildegard , Hallek Michael
Published: July 2002

Recombinant adeno-associated virus type 2 (rAAV2) is a promising vector for human somatic gene therapy. However, its broad host range is a disadvantage for some applications, because it reduces the specificity of the gene transfer. To overcome this limitation, we sought to create a versatile rAAV vector targeting system which would allow us to redirect rAAV binding to specific cell surface receptors by simple coupling of different ligands to its capsid. For this purpose, an immunoglobulin G (IgG) binding domain of protein A, Z34C, was inserted into the AAV2 capsid at amino acid position 587. The resulting AAV2-Z34C mutants could be packaged and purified to high titers and bound to IgG molecules. rAAV2-Z34C vectors coupled to antibodies against CD29 (β
1
-integrin), CD117 (c-kit receptor), and CXCR4 specifically transduced distinct human hematopoietic cell lines. In marked contrast, no transduction was seen in the absence of antibodies or in the presence of specific blocking reagents. These results demonstrate for the first time that an immunoglobulin binding domain can be inserted into the AAV2 capsid and coupled to various antibodies, which mediate the retargeting of rAAV vectors to specific cell surface receptors.
Differential Activation of Innate Immune Responses by Adenovirus and Adeno-Associated Virus Vectors
Authors: Zaiss Anne-Kathrin , Liu Qiang , Bowen Gloria P. , Wong Norman C. W. , Bartlett Jeffrey S. , Muruve Daniel A.
Published: July 2002

Adenovirus vectors induce acute inflammation of infected tissues due to activation of the innate immune system and expression of numerous chemokines and cytokines in transduced target cells. In contrast, adeno-associated virus (AAV) vectors are not associated with significant inflammation experimentally or clinically. We tested the ability of AAV vectors to induce the expression of chemokines in vitro and to activate the innate immune system in vivo. In human HeLa cells and murine renal epithelium-derived cells (REC cells) the adenovirus vector AdlacZ induced the expression of multiple inflammatory chemokines including RANTES, interferon-inducible protein 10 (IP-10), interleukin-8 (IL-8), MIP-1β, and MIP-2 in a dose-dependent manner. The use of AAVlacZ did not induce the expression of these chemokines above baseline levels despite 40-fold-greater titers than AdlacZ and greater amounts of intracellular AAVlacZ genomes according to Southern and slot blot analysis. This finding confirmed that the lack of AAVlacZ induction of chemokine was not due to reduced transduction. In DBA/2 mice, the intravenous administration of 2.5 × 1011particles of AAVlacZ resulted in the rapid induction of liver tumor necrosis factor alpha (TNF-α), RANTES, IP-10, MIP-1β, MCP-1, and MIP-2 mRNAs. However, 6 h following injection, chemokine mRNA levels returned to baseline. As expected, administration of 10-fold less AdlacZ caused an induction of liver TNF-α and chemokine mRNAs that persisted for more than 24 h posttransduction. Whereas intravenous administration of 2.5 × 1011particles of AAVlacZ triggered a transient infiltration of neutrophils and CD11b+cells into liver, this response stood in contrast to widespread inflammation and toxicity induced by AdlacZ. Kupffer cell depletion abolished AAVlacZ but not AdlacZ-induced chemokine expression and neutrophil infiltration. In summary, these results show that AAV vectors activate the innate immune system to a lesser extent than do adenovirus vectors and offer a possible explanation for the reduced inflammatory properties of AAV compared to adenovirus vectors.
Permanganate Chemical Oscillators with Cyclic Diketones
Authors: Olexová Anna , Melicherčík Milan , Treindl Ľudovít
Published: July 2002

Permanganate chemical oscillators with 1,3-cyclopentanedione, 1,3-cyclohexanedione and dimedone (5,5-dimethyl-1,3-cyclohexanedione) in a CSTR (continuous-flow, stirred tank reactor) are described. The oscillatory systems under study are remarkable in that the oscillations are well developed, but no kinetic bistability has been found. Presumably, bistability may not be a pre-requisite for oscillations to occur.
Are 1,4-Dihydropyrazines Antiaromatic? Ab initio Study of 1,4-Dihydropyrazines and Their Tetrahydro Derivatives
Authors: Vlček Pavel , Havlas Zdeněk , Pavlíček Zdeněk
Published: July 2002

A set of twenty molecules containing 1,4-dihydro- or tetrahydropyrazine ring was calculated using ab initio methods. This set also includes previously prepared diacetyl- or disilyldihydropyrazines. Structures of 1,4-dihydropyrazine derivatives are strongly dependent on ring substituents and change from planar to heavily distorted boat conformations. In the planar and near-planar structures of some 1,4-diacyl- or 1,4-diformyl-1,4-dihydropyrazines, conjugation of nitrogen lone pairs and ring bond π electrons is small. Structures, bond lengths and bond orders of 1,4-dihydropyrazines and their tetrahydro derivatives are similar. The isodesmic energy shows tendency rather to aromatic then to antiaromatic conjugation. On the basis of structural, electronic and energy arguments it is proposed to classify 1,4-dihydropyrazines as nonaromatic compounds.
Electrochemical Study of Taylor-Couette Flow by Limiting Diffusion Current Method
Authors: Sobolík Václav
Published: July 2002

Steady Taylor vortices were studied by electrodiffusion probes in the gap between coaxial cylinders. The inner cylinder was driven by a stepping motor and the outer cylinder was fixed. The viscosity of standard potassium hexacyanoferrates (III) and (IV) aqueous solution was increased to 2.52 mPa s by addition of poly(alkylene glycol) Emkarox 45. The velocity gradient components were measured by two three-segment probes at the wall of the outer cylinder for four radius ratios, R1/R2 = 0.8, 0.75, 0.65 and 0.6. The axial distribution of the azimuthal and axial components of velocity gradient was mapped while Taylor vortices were swept along the probes by a slow axial flow. The components of velocity gradient were described by fourth-order Fourier series. Generalized dependencies were found of the Fourier coefficients on Taylor number. A vertical shift of the probes made it possible to calculate the wavelength and the drifting velocity of Taylor vortices. Critical Taylor numbers were estimated from the axial component of velocity gradient and by the flow visualization using a rheoscopic liquid. The torque was calculated from the azimuthal component of velocity gradient.
Effect of the Structure of Unsaturated Hydrocarbons and Alcohols on Their Reactivity and Adsorptivity in Hydrogenation
Authors: Kačer Petr , Novák Petr , Červený Libor
Published: July 2002

Competitive hydrogenations of unsaturated hydrocarbons and unsaturated alcohols using a palladium supported catalyst, were studied under atmospheric pressure at 25 °C. From the acquired data and from the hydrogenation of each individual substrate, kinetic and adsorption parameters were determined. It was found that the hydroxyl group position relative to the double bond has no significant effect on the reactivity of the studied unsaturated alcohols; however, it has a major effect on their adsorptivity. Reactivity and adsorptivity of unsaturated hydrocarbons depended on the double bond position in substrates.
On the Determination and Use of Reduction Potentials of Short-Lived Radicals. A Review
Authors: Lund Henning , Skov Karen , Pedersen Steen Uttrup , Lund Torben , Daasbjerg Kim
Published: July 2002

A method, the "competition method", for the determination of reduction potentials and estimation of standard potentials for short-lived radicals is reviewed. Applications of the reduction potentials of radicals as arguments for reaction mechanisms are presented for the Grignard reaction, the photoreduction of ketones with alcohols, and the SRN1 reaction. Reductions induced by hydroxide ions are discussed in more detail, and the classic reaction between nitrosobenzene and hydroxide ion in aqueous solution is used as an example of such a reaction. A nucleophilic attack by hydroxide ion rather than an electron transfer initiates the reduction sequence. A review with 26 references.
Comparative Electrochemical Study of Some Phenothiazines with Carbon Paste, Solid Carbon Paste and Glass-Like Carbon Electrodes
Authors: Sandulescu Robert V. , Mirel Simona M. , Oprean Radu N. , Lotrean Simion
Published: July 2002

In order to obtain modified electrodes with phenothiazines and to develop electrochemical methods for their determination in pharmaceutical formulations, promazine maleate, promethazine maleate and levomepromazine, were studied by linear sweep voltammetry using different types of working electrodes: carbon paste, solid carbon paste and glass-like carbon electrodes. A comparative electrochemical study of the above mentioned pheno- thiazines was performed in aqueous-alcoholic solutions, investigating the influence of pH, ionic strength and concentration on the current-potential curves. Linear sweep voltammetry in potential range from -0.1 to +1.3 V revealed that the oxidation potential and the current, strongly depend on the type of electrode and pH, the best results being obtained in acid buffer (pH 1.0). The current intensity depending linearly on the concentration in the range of 2.5·10-5-5·10-4 M promazine maleate, 2.5·10-5-2.5·10-4 M promethazine maleate and 6.2·10-5-1.2·10-3 M levomepromazine permits the development of electroanalytical methods to determine these phenothiazines in pharmaceuticals. The electrochemical determination yielded results comparable with spectrophotometric methods. Linear sweep voltammetry of carbon paste electrodes modified by incorporation of phenothiazines opens the possibility to use them as mediators in the design of some enzyme selective electrodes.
The “piriformis syndrome”—myth or reality?
Authors: McCrory Paul
Published: July 2002

This article has been retracted. See the retraction notice for details. The PDF is retained for transparency.
The reliability and validity of the physical activity questions in the WHO health behaviour in schoolchildren (HBSC) survey: a population study
Authors: Booth M L , Okely A D , Chey T , Bauman A
Published: July 2002

Objective—To assess the test-retest reliability and validity of the physical activity questions in the World Health Organisation health behaviour in schoolchildren (WHO HBSC) survey.

Methods—In the validity study, the Multistage Fitness Test was administered to a random sample of year 8 (mean age 13.1 years; n = 1072) and year 10 (mean age 15.1 years; n = 954) high school students from New South Wales (Australia) during February/March 1997. The students completed the self report instruments on the same day. An independent sample of year 8 (n = 121) and year 10 (n = 105) students was used in the reliability study. The questionnaire was administered to the same students on two occasions, two weeks apart, and test-retest reliability was assessed. Students were classified as either active or inadequately active on their combined responses to the questionnaire items. Kappa and percentage agreement were assessed for the questionnaire items and for a two category summary measure.

Results—All groups of students (boys and girls in year 8 and year 10) classified as active (regardless of the measure) had significantly higher aerobic fitness than students classified as inadequately active. As a result of highly skewed binomial distributions, values of kappa were much lower than percentage agreement for test-retest reliability of the summary measure. For year 8 boys and girls, percentage agreement was 67% and 70% respectively, and for year 10 boys and girls percentage agreement was 85% and 70% respectively.

Conclusions—These brief self report questions on participation in vigorous intensity physical activity appear to have acceptable reliability and validity. These instruments need to be tested in other cultures to ensure that the findings are not specific to Australian students. Further refinement of the measures should be considered.
Impact of HIV infection on tuberculosis
Authors: Zumla Alimuddin , Malon Patrick , Henderson Jane , Grange John M
Published: July 2002

Tuberculosis is increasing in prevalence in many countries and is now the leading infectious cause of death world wide, being responsible for three million deaths annually. Infection with HIV, likewise increasing in prevalence, has emerged as the most important predisposing factor for developing overt tuberculosis in people co-infected with Mycobacterium tuberculosis. Owing to the widespread geographical overlap of these two infections, it is estimated that in 1999, HIV related tuberculosis will reach one million cases and will cause 30% of the expected 2.5 million AIDS related deaths. Tuberculosis in HIV infected individuals may have unusual clinical features and can cause diagnostic difficulties. Despite the effectiveness of modern short course treatment, the mortality of HIV related tuberculosis during and after treatment remains high, and this may be due to other HIV related infections. The “cursed duet” of infection with both HIV and M tuberculosis is generating a threat to human health of unparalleled proportions which, if not taken seriously by health workers and decision makers, could become totally unmanageable.
Intramuscular lipomatosis of tongue
Authors: Thomas S , Varghese B T , Sebastian P , Koshy C M , Mathews A , Abraham E K
Published: July 2002

A rare case of intramuscular lipomatosis of the tongue with intramuscular invasion in a 42 year old man is presented. The literature is reviewed and the clinical features, pathology, and treatment are discussed briefly.
Seasonal effects of food provisioning on body fat, insulin, and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi)
Authors: Nunes Scott , Muecke Eva-Maria , Holekamp Kay E
Published: July 2002

We evaluated the relationship between body fat and the metabolic hormones insulin and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi). Some free-living juveniles were provisioned with extra food high in fat and calories, and unprovisioned juveniles were used as controls. Body fat (as a percentage of body mass) of squirrels was regularly evaluated using non-invasive methods. Blood samples were also regularly collected from juveniles and assayed for plasma concentrations of insulin and corticosterone. Provisioned juveniles were fatter than unprovisioned juveniles during most of the active season, but differences in body fat disappeared near the end of summer as juveniles began fattening for hibernation. Thus, our data indicate that although body fat may fluctuate with energy availability early in the active season, it is regulated at precise levels as squirrels prepare for winter. Plasma corticosterone concentrations did not differ between provisioned and unprovisioned juveniles. However, plasma insulin concentrations were greater in provisioned than in unprovisioned juveniles early in the summer. Differences in insulin concentrations disappeared later in the active season, just prior to the disappearance of differences in body fat. Moreover, plasma insulin concentrations were significantly correlated with subsequent changes in body fat. Thus, our data suggest a link between insulin and seasonal regulation of body fat in juvenile S. beldingi.
NLC2-DECOMPOSITION IN POLYNOMIAL TIME
Authors: JOHANSSON ÖJVIND
Published: July 2002

NLC k is a family of algebras on vertex-labeled graphs introduced by Wanke. An NLC-decomposition of a graph is a derivation of this graph from single vertices using the operations in question. The width of the decomposition is the number of labels used, and the NLC-width of the graph is the smallest width among its NLC-decompositions. Many difficult graph problems can be solved efficiently with dynamic programming if an NLC-decomposition of low width is given for the input graph. It is unknown, though, whether arbitrary graphs of NLC-width at most k can be decomposed with k labels in polynomial time. So far this has been possible only for k = 1, which corresponds to cographs. In this paper, an algorithm is presented that works for k = 2. It runs in O(n4 log n) time and uses O(n2) space. Related concepts: clique-decomposition, clique-width.
OPTIMAL SOFTWARE PIPELINING UNDER RESOURCE CONSTRAINTS
Authors: FIMMEL DIRK , MÜLLER JAN
Published: July 2002

In this paper we present a novel approach to find an optimum loop schedule under consideration of limited resources. The initiation interval λ is assumed to be a rational number. Our approach is formulated as a single optimization problem that can be solved using integer linear programming. The objective is to minimize the initiation interval, while both numerator and denominator of λ can be incorporated as variables of the optimization problem. the resources (functional units) may have a pipeline architecture; the approach also supports heterogeneous functional units.
ON FLIPS IN POLYHEDRAL SURFACES
Authors: AICHHOLZER OSWIN , ALBOUL LYUBA S. , HURTADO FERRAN
Published: July 2002

Let V be a finite point set in 3-space, and let [Formula: see text] be the set of triangulated polyhedral surfaces homeomorphic to a sphere and with vertex set V. Let abc and cbd be two adjacent triangles belonging to a surface [Formula: see text]; the flip of the edge bc would replace these two triangles by the triangles abd and adc. The flip operation is only considered when it does not produce a self-intersecting surface. In this paper we show that given two surfaces S1, [Formula: see text], it is possible that there is no sequence of flips transforming S1 into S2, even in the case that V consists of points in convex position.
MERGEABLE DOUBLE-ENDED PRIORITY QUEUES
Authors: CHO SEONGHUN , SAHNI SARTAJ
Published: July 2002

We show that the leftist tree data structure may be adapted to obtain data structures that permit the double-ended priority queue operations Insert, DeleteMin, DeleteMax, and Merge to be done in O( log n) time where n is the size of the resulting queue. The operations FindMin and FindMax can be done in O(1) time. Experimental results are also presented.
A POLYNOMIAL-TIME ALGORITHM FOR FINDING TOTAL COLORINGS OF PARTIAL k-TREES
Authors: ISOBE SHUJI , ZHOU XIAO , NISHIZEKI TAKAO
Published: July 2002

A total coloring of a graph G is a coloring of all elements of G, i.e. vertices and edges, in such a way that no two adjacent or incident elements receive the same color. Many combinatorial problems can be efficiently solved for partial k-trees, that is, graphs of treewidth bounded by a constant k. However, no polynomial-time algorithm has been known for the problem of finding a total coloring of a given partial k-tree with the minimum number of colors. This paper gives such a first polynomial-time algorithm.
GROUND STATE PROPERTIES OF THE NELSON HAMILTONIAN: A GIBBS MEASURE-BASED APPROACH
Authors: BETZ VOLKER , HIROSHIMA FUMIO , LŐRINCZI JÓZSEF , MINLOS ROBERT A. , SPOHN HERBERT
Published: July 2002

The Nelson model describes a quantum particle coupled to a scalar Bose field. We study properties of its ground state through functional integration techniques in case the particle is confined by an external potential. We obtain bounds on the average and the variance of the Bose field both in position and momentum space, on the distribution of the number of bosons, and on the position space distribution of the particle.
NUMERICAL SOLUTIONS OF QUANTUM MECHANICAL PROBLEMS USING THE BASIS-SPLINE COLLOCATION METHOD
Authors: ODERO D. O. , PEACHER J. L. , MADISON D. H.
Published: July 2002

The time-dependent and time-independent Schrödinger equations have been numerically solved for several quantum mechanical problems with known analytical solutions using the basis-spline collocation algorithm. This algorithm has been demonstrated to be efficient and versatile. The results from these calculations illustrate the necessary numerical considerations required for solving both time-independent and time-dependent Schrödinger equations and form a basis that could be used for solving these and similar problems.
SZNAJD SOCIOPHYSICS MODEL ON A TRIANGULAR LATTICE: FERRO AND ANTIFERROMAGNETIC OPINIONS
Authors: CHANG IKSOO
Published: July 2002

The Sznajd sociophysics model is generalized on the triangular lattice with pure antiferromagnetic opinion and also with both ferromagnetic and antiferromagnetic opinions. The slogan of the trade union "united we stand, divided we fall" can be realized via the propagation of ferromagnetic opinion of adjacent people in the union, but the propagation of antiferromagnetic opinion can be observed among the third countries between two big super powers or among the family members of conflicting parents. Fixed points are found in both models. The distributions of relaxation time of the mixed model are dispersed and become closer to log–normal as the initial concentration of down spins approaches 0.5, whereas for pure antiferromagnetic spins, they are collapsed into one master curve, which is roughly log–normal. We do not see the phase transition in the model.
APPLICATION OF THE SZNAJD SOCIOPHYSICS MODEL TO SMALL-WORLD NETWORKS
Authors: ELGAZZAR A. S.
Published: July 2002

The Sznajd model for the opinion formation is generalized to small-world networks. This generalization destroyed the stalemate fixed point. Then a simple definition of leaders is included. No fixed points are observed. This model displays some interesting aspects in sociology. The model is investigated using time series analysis.
ON THE AMELIORATION OF QUADRATIC DIVERGENCES
Authors: DELBOURGO R. , SCADRON M. D.
Published: July 2002

Once massless quadratically divergent tadpole diagrams are discarded, because they contain no intrinsic scale, it is possible to convert other divergences into logarithmic form, using partial fraction identities; this includes the case of quadratic divergences, as has been applied to the linear sigma model. However the procedure must be carried out with due care, paying great attention to correct numerator factors.
QUANTUM GEOMETRY AS A RELATIONAL CONSTRUCT
Authors: CORICHI ALEJANDRO , RYAN MICHAEL P. , SUDARSKY DANIEL
Published: July 2002

The problem of constructing a quantum theory of gravity is considered from a novel viewpoint. It is argued that any consistent theory of gravity should incorporate a relational character between the matter constituents of the theory. In particular, the traditional approach of quantizing a space–time metric is criticized and two possible avenues for constructing a satisfactory theory are put forward.
THE NEUTRINOLESS DOUBLE β DECAY AND THE NEUTRINO MASS HIERARCHY
Authors: HABA NAOYUKI , SUZUKI TOMOHARU
Published: July 2002

Recently the evidence of the neutrinoless double β (0νββ) decay has been announced. This means that neutrinos are Majorana particles and their mass hierarchy is forced to certain patterns in the diagonal basis of charged lepton mass matrix. We estimate the magnitude of 0νββ decay in the classification of the neutrino mass hierarchy patterns as Type A, m1,2 ≪ m3, Type B, m1 ~ m2 ≫ m3, and Type C, m1 ~ m2 ~ m3, where mi is the ith generation neutrino absolute mass. The data of 0νββ decay experiment suggest that the neutrino mass hierarchy pattern should be Type B or C. Type B predicts a small magnitude of 0νββ decay which is just edge of the allowed region of experimental value in 95% c.l., where Majorana CP phases should be in a certain parameter region. Type C can induce the suitably large amount of 0νββ decay which is consistent with the experimental data, where overall scale of degenerate neutrino mass plays a crucial role, and its large value can induce the large 0νββ decay in any parameter regions of Majorana CP phases.
REDUCIBILITY AND BOSONIZATION OF PARASUPERSYMMETRIC AND ORTHOSUPERSYMMETRIC QUANTUM MECHANICS
Authors: QUESNE C. , VANSTEENKISTE N.
Published: July 2002

Order-p parasupersymmetric and orthosupersymmetric quantum mechanics are shown to be fully reducible when they are realized in terms of the generators of a generalized deformed oscillator algebra and a ℤp+1-grading structure is imposed on the Fock space. The irreducible components provide p + 1 sets of bosonized operators corresponding to both unbroken and broken cases. Such a bosonization is minimal.
AB-INITIO EVALUATION OF LOCAL EFFECTIVE INTERACTIONS IN α′ NAV2O5
Authors: LEPETIT MARIE-BERNADETTE , SUAUD NICOLAS
Published: July 2002

We compute by means of extensive quantum chemistry methods the nearest-neighbour effective exchange and hopping integrals for α′ NaV2O5. We find that, unlike usually assumed, the system is basically a two-dimensional asymmetric triangular Heisenberg lattice, where the sites represent unpaired electrons delocalised on the VOV rungs.