bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Organization and Hypoxic Activation of the Kaposi's Sarcoma-Associated Herpesvirus ORF34-37 Gene Cluster
Authors: Haque Muzammel , Wang Victoria , Davis David A. , Zheng Zhi-Ming , Yarchoan Robert 
Published: June 2006

ABSTRACT
Kaposi's
sarcoma-associated herpesvirus (KSHV) is the etiologic agent for
Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). We
previously reported that hypoxia activates KSHV lytic replication and
that the promoter for open reading frame 34 (ORF34) contains a
functional hypoxia-responsive element (HRE). ORF34 is part of a cluster
of lytic genes (ORF34-37) that includes ORF36, a phosphotransferase,
and ORF37, a shutoff exonuclease. Rapid amplification of cDNA ends
analysis revealed that they share a common polyadenylation signal but
have two start sites. Two transcripts were identified, one 3.4 kb
encoding ORF35-37, and the other 4.2 kb encoding ORF34 and also having
coding potential for ORF35-37. Exposure of PEL cell lines to hypoxia
induced messages of lengths consistent with those of these transcripts.
Reporter assays with Hep3B cells showed activation of both transcripts
by hypoxia. The ORF34-37 promoter region has six consensus HREs.
Sequential deletion, site-directed mutagenesis experiments, and
Northern blot analysis of RNA produced by constructs indicated that the
second HRE (HRE-2) plays a critical role in the hypoxic activation of
both RNA transcripts. The ORF35-37 transcript was upregulated by
cotransfected hypoxia-inducible factor (HIF). Electrophoretic mobility
shift assays demonstrated that HRE-2 and ancillary sequences bind and
compete for HIF with hypoxic Hep3B nuclear extract. The activation of
this gene cluster by hypoxia may have implications for the pathogenesis
of PEL and KS. Moreover, the activation of ORF36 by hypoxia might be
exploited to develop targeted therapy for PEL, which arises in a
hypoxic environment (pleural
effusions).
Localization of ERK/MAP Kinase Is Regulated by the Alphaherpesvirus Tegument Protein Us2
Authors: Lyman Mathew G. , Randall Jessica A. , Calton Christine M. , Banfield Bruce W. 
Published: June 2006

ABSTRACT
Many different viruses activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein (MAP) kinase signaling pathway during infection and require ERK activation for the efficient execution of their replication programs. Despite these findings, no virus-encoded proteins have been identified that directly modulate ERK activities. In an effort to determine the function of a conserved alphaherpesvirus structural protein called Us2, we screened a yeast two-hybrid library derived from NIH 3T3 cells and identified ERK as a Us2-interacting protein. Our studies indicate that Us2 binds to ERK in virus-infected cells, mediates the incorporation of ERK into the virion, and inhibits the activation of ERK nuclear substrates. The association of Us2 with ERK leads to the sequestration of ERK at the plasma membrane and to a perinuclear vesicular compartment, thereby keeping ERK out of the nucleus. Us2 can bind to activated ERK, and the data suggest that Us2 does not inhibit ERK enzymatic activity. The treatment of cells with U0126, a specific inhibitor of ERK activation, resulted in a substantial delay in the release of virus from infected cells that was more pronounced with a virus deleted for Us2 than with parental and repaired strains, suggesting that both ERK and Us2 activities are required for efficient virus replication. This study highlights an additional complexity to the activation of ERK by viruses, namely, that localization of active ERK can be altered by virus-encoded proteins.
Protein-Primed and De Novo Initiation of RNA Synthesis by Norovirus 3D
pol
Authors: Rohayem Jacques , Robel Ivonne , Jäger Katrin , Scheffler Ulrike , Rudolph Wolfram 
Published: June 2006

ABSTRACT

Noroviruses (
Caliciviridae
) are RNA viruses with a single-stranded, positive-oriented polyadenylated genome. To date, little is known about the replication strategy of norovirus, a so-far noncultivable virus. We have examined the initiation of replication of the norovirus genome in vitro, using the active norovirus RNA-dependent RNA polymerase (3D
pol
), homopolymeric templates, and synthetic subgenomic or antisubgenomic RNA. Initiation of RNA synthesis on homopolymeric templates as well as replication of subgenomic polyadenylated RNA was strictly primer dependent. In this context and as observed for other enteric RNA viruses, i.e., poliovirus, a protein-primed initiation of RNA synthesis after elongation of the VPg by norovirus 3D
pol
was postulated. To address this question, norovirus VPg was expressed in
Escherichia coli
and purified. Incubation of VPg with norovirus 3D
pol
generated VPg-poly(U), which primed the replication of subgenomic polyadenylated RNA. In contrast, replication of antisubgenomic RNA was not primer dependent, nor did it depend on a leader sequence, as evidenced by deletion analysis of the 3′ termini of subgenomic and antisubgenomic RNA. On nonpolyadenylated RNA, i.e., antisubgenomic RNA, norovirus 3D
pol
initiated RNA synthesis de novo and terminated RNA synthesis by a poly(C) stretch. Interestingly, on poly(C) RNA templates, norovirus 3D
pol
initiated RNA synthesis de novo in the presence of high concentrations of GTP. We propose a novel model for initiation of replication of the norovirus genome by 3D
pol
, with a VPg-protein-primed initiation of replication of polyadenylated genomic RNA and a de novo initiation of replication of antigenomic RNA.
Modest but Reproducible Inhibition of Human Immunodeficiency Virus Type 1 Infection in Macrophages following LEDGFp75 Silencing
Authors: Zielske Steven P. , Stevenson Mario 
Published: June 2006

ABSTRACT
LEDGFp75 is a cellular protein which binds human immunodeficiency virus type 1 (HIV-1) integrase with high specificity and affinity but whose function in infection has not been defined. We infected LEDGFp75-deficient primary macrophages with wild-type HIV in order to assess potential infection phenotypes which would provide clues to LEDGFp75 function. Silencing of LEDGFp75 by 70 to 80% resulted in an average of 53% reduced infection of macrophages by HIV. Analysis of infection intermediates showed that integration, but not two-long-terminal-repeat (2LTR) circles or late cDNAs, was reduced up to 74% in LEDGFp75-deficient macrophages. Therefore, LEDGFp75 has a modest involvement in HIV-1 integration in macrophages.
The Capsid Protein of Beak and Feather Disease Virus Binds to the Viral DNA and Is Responsible for Transporting the Replication-Associated Protein into the Nucleus
Authors: Heath Livio , Williamson Anna-Lise , Rybicki Edward P. 
Published: June 2006

ABSTRACT
Circoviruses lack an autonomous DNA polymerase and are dependent on the replication machinery of the host cell for de novo DNA synthesis. Accordingly, the viral DNA needs to cross both the plasma membrane and the nuclear envelope before replication can occur. Here we report on the subcellular distribution of the beak and feather disease virus (BFDV) capsid protein (CP) and replication-associated protein (Rep) expressed via recombinant baculoviruses in an insect cell system and test the hypothesis that the CP is responsible for transporting the viral genome, as well as Rep, across the nuclear envelope. The intracellular localization of the BFDV CP was found to be directed by three partially overlapping bipartite nuclear localization signals (NLSs) situated between residues 16 and 56 at the N terminus of the protein. Moreover, a DNA binding region was also mapped to the N terminus of the protein and falls within the region containing the three putative NLSs. The ability of CP to bind DNA, coupled with the karyophilic nature of this protein, strongly suggests that it may be responsible for nuclear targeting of the viral genome. Interestingly, whereas Rep expressed on its own in insect cells is restricted to the cytoplasm, coexpression with CP alters the subcellular localization of Rep to the nucleus, strongly suggesting that an interaction with CP facilitates movement of Rep into the nucleus.
Factors Determining the Breadth and Potency of Neutralization by V3-Specific Human Monoclonal Antibodies Derived from Subjects Infected with Clade A or Clade B Strains of Human Immunodeficiency Virus Type 1
Authors: Krachmarov C. P. , Honnen W. J. , Kayman S. C. , Gorny M. K. , Zolla-Pazner S. , Pinter Abraham 
Published: June 2006

ABSTRACT

The neutralizing activities of anti-V3 antibodies for HIV-1 isolates is affected both by sequence variation within V3 and by epitope masking by the V1/V2 domain. To analyze the relative contribution of V3 sequence variation, chimeric Env genes that contained consensus V3 sequences from seven HIV-1 subtypes in the neutralization-sensitive SF162 Env backbone were constructed. Resulting viral pseudotypes were tested for neutralization by 15 anti-V3 MAbs isolated from humans infected with viruses of either subtype B (anti-V3
B
MAbs) or subtype A (anti-V3
A
MAbs). Pseudovirions with the subtype B consensus V3 sequence were potently neutralized (IC
50
< 0.006 μg/ml) by all but one of these MAbs, while pseudovirions with V3 subtypes A, C, F, H, AG, and AE were generally neutralized more effectively by anti-V3
A
MAbs than by anti-V3
B
MAbs. A V1/V2-masked Env version of SF162 Env with the consensus B V3 sequence was also neutralized by these MAbs, although with considerably lower potency, while similarly masked chimeras with V3 sequences of subtype A, C, or AG were weakly neutralized by anti-V3
A
MAbs but not by anti-V3
B
MAbs. Mutations in the V1/V2 domain of YU-2 Env increased the sensitivity of this highly resistant Env to a pool of anti-V3
B
MAbs several thousand-fold. These results demonstrated (i) the exceptional sensitivity of representative V3 domains of multiple subtypes to neutralization in the absence of epitope masking, (ii) the broader neutralizing activity of anti-V3
A
MAbs for viruses containing diverse V3 sequences, and (iii) the generality and dominant effect of V1/V2 masking on restriction of V3-mediated neutralization.
CD1d Mediates T-Cell-Dependent Resistance to Secondary Infection with Encephalomyocarditis Virus (EMCV) In Vitro and Immune Response to EMCV Infection In Vivo
Authors: Ilyinskii Petr O. , Wang Ruojie , Balk Steven P. , Exley Mark A. 
Published: June 2006

ABSTRACTThe innate and adaptive immune responses have evolved distinct strategies for controlling different viral pathogens. Encephalomyocarditis virus (EMCV) is a picornavirus that can cause paralysis, diabetes, and myocarditis within days of infection. The optimal innate immune response against EMCV in vivo requires CD1d. Interaction of antigen-presenting cell CD1d with distinct natural killer T-cell (“NKT”) populations can induce rapid gamma interferon (IFN-γ) production and NK-cell activation. The T-cell response of CD1d-deficient mice (lacking all NKT cells) against acute EMCV infection was further studied in vitro and in vivo. EMCV persisted at higher levels in CD1d-knockout (KO) splenocyte cultures infected in vitro. Furthermore, optimal resistance to repeat cycles of EMCV infection in vitro was also shown to depend on CD1d. However, this was not reflected in the relative levels of NK-cell activation but rather by the responses of both CD4+and CD8+T-cell populations. Repeated EMCV infection in vitro induced less IFN-γ and alpha interferon (IFN-α) from CD1d-deficient splenocytes than with the wild type. Furthermore, the level of EMCV replication in wild-type splenocytes was markedly and specifically increased by addition of blocking anti-CD1d antibody. Depletion experiments demonstrated that dendritic cells contributed less than the combination of NK and NKT cells to anti-EMCV responses and that none of these cell types was the main source of IFN-α. Finally, EMCV infection in vivo produced higher levels of viremia in CD1d-KO mice than in wild-type animals, coupled with significantly less lymphocyte activation and IFN-α production. These results point to the existence of a previously unrecognized mechanism of rapid CD1d-dependent stimulation of the antiviral adaptive cellular immune response.
Fitness Comparison of Thymidine Analog Resistance Pathways in Human Immunodeficiency Virus Type 1
Authors: Hu Zixin , Giguel Françoise , Hatano Hiroyu , Reid Patrick , Lu Jing , Kuritzkes Daniel R. 
Published: June 2006

ABSTRACTResistance to zidovudine (ZDV) results from thymidine analog resistance mutations (TAMs) at human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) codons 41, 67, 70, 210, 215, and 219. Two mutations are possible at codon 215: Y or F. Whereas T215Y occurs alone or with M41L and L210W (TAM-1 pattern), T215F rarely occurs with these mutations or by itself; it is found instead with D67N, K70R, and K219Q (TAM-2 pattern). The L210W mutation most often occurs with M41L and T215Y and rarely occurs with the T215F or TAM-2 mutation. To explain these associations, TAMs were introduced into HIV-1Hxb2by site-directed mutagenesis and expressed in recombinant viruses. Viral replication kinetics, relative fitness, and infectivity were tested in the absence or presence of ZDV. Viruses carrying the 215Y mutation showed faster replication kinetics and greater relative fitness than did T215F mutants in the absence or presence of ZDV. In addition, T215Y mutants showed greater infectivity than did wild-type HIV-1 over a range of ZDV concentrations, but T215F mutants had only a modest advantage over the wild-type virus. Whereas introduction of L210W improved the relative fitness of an M41L/T215Y mutant in the presence of ZDV, introduction of this mutation into a D67N/K70R/K219Q background resulted in decreased relative fitness in the presence or absence of drug. By contrast, introduction of T215F into the D67N/K70R/K219Q background increased viral fitness in the presence of ZDV. These results help explain why T215Y but not T215F usually emerges as the first major TAM, as well as the clustering of L210W with TAM-1 mutations and T215F with TAM-2 mutations.
Ultrasound guided electrocoagulation in patients with chronic non-insertional Achilles tendinopathy: a pilot study
Authors: Boesen M Ilum , Torp-Pedersen S , Koenig M Juhl , Christensen R , Langberg H , Hölmich P , Nielsen M Bachmann , Bliddal H 
Published: June 2006

Background:High resolution colour Doppler ultrasound shows intratendinous Doppler activity in patients with chronic Achilles tendinopathy. Treatment of this neovascularisation with sclerosing therapy seems to relieve the pain. However, the procedure often has to be repeated.Objective:To investigate the effect of electrocoagulation of the neovessels on tendon pain and tendon vascularity in patients with chronic Achilles tendinopathy.Methods:Colour Doppler ultrasound guided electrocoagulation was used on vessels in the ventral portion of the Achilles tendon in 11 patients (seven men, four women, mean age 41 years) with painful chronic mid-portion Achilles tendinosis. A unipolar coagulation device was used.Results:One patient dropped out after two months (dissatisfied with the results). The remaining 10 patients (91%) were satisfied. These 10 patients were still satisfied at six months of follow up and had returned to their previous level of activity. All 10 patients were “cured” after one treatment. The patient who dropped out received two treatments because of lack of progress. There was significantly reduced pain (Likert pain scale, 0–10) during activity, from a median of 7 (range 4 to 10) at baseline to 0 (0 to 8) at six months’ follow up (p<0.005); and at rest, from 1.5 (1 to 5) to 0 (0 to 8) (p = 0.005). In all patients, vascularisation was unchanged at the six months follow up, with no significant change in semiquantitative or quantitative colour scoring.Conclusions:Coagulation in the area with vessels entering the tendon appears to be effective treatment for painful chronic mid-tendinous Achilles tendinopathy. No effect on the intratendinous Doppler activity could be detected, suggesting that the effect is independent of changes in blood flow. Localisation of hyperaemia appears to be the key to the pathology and for targeting the treatment. One explanation could be that the effect is obtained by destruction of nerves accompanying the vessels.
Phosphodiesterase 4 inhibition of β2-integrin adhesion caused by leukotriene B4and TNF-α in human neutrophils
Authors: Meliton A. Y. , Muñoz N. M. , Lambertino A. , Boetticher E. , Learoyd J. , Zhu X. , Leff A. R. 
Published: June 2006

Phosphodiesterase (PDE)4 inhibition attenuates neutrophilic inflammation in chronic obstructive pulmonary disease. The objective of the present study was to examine the efficacy and mechanism by which PDE4 inhibition blocks adhesion of β2-integrin to an endothelial counterligand.Neutrophils (polymorphonuclear leukocytes (PMNs)) were isolated from humans receiving no medication. Adhesion was analysed by myeloperoxidase activity. The effects of cilomilast±salmeterol on the following were determined: 1) surface CD11b expression; 2) adhesion; 3) intracellular cyclic adenosine monophosphate (cAMP) concentration; and 4) extracellular signal-regulated kinase (ERK)-1/2-mediated group IVA-phospholipase A2(gIVA-PLA2) phosphorylation caused by leukotriene (LT)B4or tumour necrosis factor (TNF)-α activation.Either cilomilast or rolipram±salmeterol caused concentration-related blockade of LTB4-induced adhesion to counterligand, but had no effect on TNF-α-activated PMNs. A comparable increase in intracellular cAMP concentration for PMNs activated with LTB4and TNF-α was caused by 1 μM cilomilast and 0.1 μM salmeterol. Upregulation of surface CD11b expression and ERK-1/2 phosphorylation were blocked by cilomilast or rolipram±salmeterol for PMNs activated by LTB4, but not for cells stimulated by TNF-α. Cilomilast±salmeterol also blocked gIVA-PLA2phosphorylation caused by LTB4but not TNF-α.In conclusion, the current study demonstrates that both leukotriene B4and tumour necrosis factor-α upregulate cyclic adenosine monophosphate. However, cyclic adenosine monophosphate does not block β2-integrin adhesion caused by tumour necrosis factor-α. It was concluded that tumour necrosis factor-α prevents inhibition of extracellular signal-regulated kinase-1/2-mediated group IVA-phospholipase A2activation, which is essential for β2-integrin adhesion in polymorphonuclear leukocytes.
Clinical evaluation of a screen pneumotachograph as an in-line filter
Authors: Normand H. , Normand F. , Le Coutour X. , Metges M-A. , Mouadil A. 
Published: June 2006

The American Thoracic Society/European Respiratory Society Task Force underlined that the use of in-line filters during respiratory function tests “is an area of controversy”. The aim of the present study was to measure the contamination occurring during forced expiration downstream from a screen pneumotachograph (SP) with and without an in-line filter (Pall PF30S). A total of 40 healthy subjects performed eight consecutive maximal expiratory manoeuvres into four sterile apparatuses (A1: no filter, no SP; A2: filter-only; A3: SP-only; A4: filter and SP) in random order. A blood agar plate was fixed downstream from the apparatus. Colony-forming units (CFUs) were counted after 24 h incubation at 37°C. Of the 40 plates obtained with each apparatus, 13 were sterile with A1 (range 0–679 CFUs), 25 with A2 (0–49 CFUs), 30 with A3 (0–35 CFUs) and 39 with A4 (one CFU in the only positive plate). A1versusA2 and also A3versusA4 gave different values for the CFU number, but A2 and A3 showed similar contamination levels.The authors conclude that: 1) the in-line filter does not perform better than a screen pneumotachograph; 2) it does not eliminate the need to decontaminate the pneumotachograph; and 3) equipment placed downstream from an in-line filter and a screen pneumotachograph is almost protected from contamination.
Prehospital Standardization of Medical Airway Management: Incidence and Risk Factors of Difficult Airway
Authors: Combes Xavier , Jabre Patricia , Jbeili Chadi , Leroux Bertrand , Bastuji‐Garin Sylvie , Margenet Alain , Adnet Fréderic , Dhonneur Gilles 
Published: June 2006

Objectives:
The rate of difficult intubation in prehospital emergency medicine varies greatly among studies already published and depends on several factors. The authors' objective was to determine the rate of difficult intubations and to determine factors associated with prehospital difficult airways when a standard protocol for sedation and intubation was applied.
Methods:
This 30‐month clinical, observational, prospective study was performed in a suburb of Paris, France (Val de Marne, population 1,300,000) by a prehospital emergency medical unit. Airway management for patients who needed tracheal intubation was standardized. The pharmacological procedure recommended rapid sequence intubation for patients with spontaneous cardiac activity. In cases of difficult, laryngoscopy‐assisted intubation, a predefined algorithm was proposed. The Intubation Difficulty Score (IDS) was calculated for all patients requiring tracheal intubation, and factors associated with difficult intubation, defined by IDS of >5, were identified by using multivariate statistical analysis.
Results:
During the study period, 1,442 patients were included; 640 (44%) were in cardiorespiratory arrest, and 802 had a spontaneous cardiac activity. Deviation from the pharmacological and airway management procedures occurred in 1% of cases. When the predefined difficult airway management algorithm was followed, failure to intubate was encountered twice (0.1%). One hundred six (7.4%) patients had an IDS of >5, and 60 (4.1%) required first (n= 56) then second (n= 4) alternative techniques for tracheal intubation. Semirigid leaders allowed tracheal access in 93% of difficult‐intubation patients. One patient required a prehospital cricothyroidotomy. Factors associated with difficult intubation were the following: a history of ear, nose, or throat neoplasia or surgery; obesity; facial trauma; the operator's status; and the operator's position.
Conclusions:
If prehospital medical airway management is standardized and performed by trained operators, failure to intubate is rare (0.1%), and the incidence of difficult tracheal intubation is 7.4%, independent of cardiorespiratory status.
Kinetic Studies of the Oxygen Exchange of Chromate and Arsenate Ions with Water. Catalysis by Tellurate and Tellurite Ions
Authors: Okumura Akiko , Suda Atsuko , Saruta Atsuko , Miki Miyako 
Published: June 2006

Abstract
The oxygen exchange reaction of the chromate ions with water is catalyzed by the tellurate and tellurite ions. The catalytic reaction rate (RC), which is defined as the increase in the rate of the chromate-oxygen exchange upon the addition of Te(VI) or Te(IV), was studied by an 18O tracer method. The catalytic process has been interpreted in terms of the rapid reversible condensation of the Cr(VI) with Te(VI) or Te(IV) species to form hetero-poly anions. As exemplified for the Cr(VI)–Te(VI) reaction system, the rate law is given as the sum of kinetic terms: RC = ∑kij[Cr(VI)]i × [Te(VI)]j where [Cr(VI)]i and [Te(VI)]j denote the concentration of the various ionic species of the chromate and tellurate ions, respectively, and kij is the rate constant of the elementary reaction between (Cr(VI))i and (Te(VI))j. The catalytic rates were analyzed according to the rate law in order to obtain the rate constants kij. The catalytic reaction system As(V)–Te(IV) was also studied. The values of kij obtained for various catalytic systems were compared with each other.