bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Epidemiology of
Staphylococcus saprophyticus
Isolated from Women with Uncomplicated Community-Acquired Urinary Tract Infection
Authors: Widerström Micael , Wiström Johan , Ferry Sven , Karlsson Carina , Monsen Tor 
Published: March 2007

ABSTRACT

Staphylococcus saprophyticus
is a common cause of urinary tract infections (UTIs) in women. Little is known about the molecular epidemiology of
S. saprophyticus
UTIs. In the current study, we compared 76 isolates of
S. saprophyticus
prospectively isolated from women with uncomplicated UTI participating in a randomized placebo-controlled treatment trial performed in northern Sweden from 1995 to 1997 with 50 strains obtained in 2006 from five different locations in northern Europe with pulsed-field gel electrophoresis (PFGE). The aim was to elucidate the molecular epidemiology of this uropathogenic species and to investigate whether specific clones are associated with UTI in women. A total of 47 different PFGE profiles were detected among the 126 analyzed isolates. Ten clusters consisting of 5 to 12 isolates each showing PFGE DNA similarity of >85% were identified. Several clusters of genetically highly related isolates were detected in the original trial as well as among isolates obtained during 2006 from different locations. In the original trial, clonal persistence was found among 16 of 21 (76%) patients examined in the placebo group at follow-up 8 to 10 days after inclusion, indicating a low spontaneous short-time bacteriological cure rate. We conclude that multiple clones of
S. saprophyticus
were causing lower UTIs in women. The result suggests that some human-pathogenic clones of
S. saprophyticus
are spread over large geographical distances and that such clones may persist over long periods of time.
Corynebacterium accolens
Isolated from Breast Abscess: Possible Association with Granulomatous Mastitis
Authors: Ang Lei M. N. , Brown Hamish 
Published: March 2007

ABSTRACT

Corynebacterium accolens
is rarely isolated as a human pathogen. We describe here a case of
C. accolens
isolated from a breast abscess in a patient previously diagnosed with granulomatous mastitis. The possible association of
Corynebacterium accolens
and granulomatous mastitis in this patient is discussed.
Evaluation of the AdvanDx VRE EVIGENE Assay for Detection of
vanA
in Vancomycin-Resistant
Staphylococcus aureus
Authors: Fosheim G. E. , Carey R. B. , Limbago B. M. 
Published: March 2007

ABSTRACT

AdvanDx VRE EVIGENE, a commercial
vanA
/
vanB
DNA hybridization assay to identify vancomycin-resistant enterococci (VRE), was evaluated for the detection of
vanA
in
Staphylococcus aureus
. Performance was assessed using
S. aureus
, VRE, and vancomycin-intermediate and -susceptible isolates. The assay demonstrated 100% sensitivity and specificity when analyzed visually and by optical density.
Identification of Determinants Involved in Initiation of Hepatitis C Virus RNA Synthesis by Using Intergenotypic Replicase Chimeras
Authors: Binder Marco , Quinkert Doris , Bochkarova Olga , Klein Rahel , Kezmic Nikolina , Bartenschlager Ralf , Lohmann Volker 
Published: March 2007

ABSTRACT
The 5′ nontranslated region (NTR) and the X tail in the 3′ NTR are the least variable parts of the hepatitis C virus (HCV) genome and play an important role in the initiation of RNA synthesis. By using subgenomic replicons of the HCV isolates Con1 (genotype 1) and JFH1 (genotype 2), we characterized the genotype specificities of the replication signals contained in the NTRs. The replacement of the JFH1 5′ NTR and X tail with the corresponding Con1 sequence resulted in a significant decrease in replication efficiency. Exchange of the X tail specifically reduced negative-strand synthesis, whereas substitution of the 5′ NTR impaired the generation of progeny positive strands. In search for the proteins involved in the recognition of genotype-specific initiation signals, we analyzed recombinant nonstructural protein 5B (NS5B) RNA polymerases of both isolates and found some genotype-specific template preference for the 3′ end of positive-strand RNA in vitro. To further address genotype specificity, we constructed a series of intergenotypic replicon chimeras. When combining NS3 to NS5A of Con1 with NS5B of JFH1, we observed more-efficient replication with the genotype 2a X tail, indicating that NS5B recognizes genotype-specific signals in this region. In contrast, a combination of the NS3 helicase with NS5A and NS5B was required to confer genotype specificity to the 5′ NTR. These results present the first genetic evidence for an interaction between helicase, NS5A, and NS5B required for the initiation of RNA synthesis and provide a system for the specific analysis of HCV positive- and negative-strand syntheses.
Herpes Simplex Virus Immediate-Early Protein ICP22 Triggers Loss of Serine 2-Phosphorylated RNA Polymerase II
Authors: Fraser Kathryn A. , Rice Stephen A. 
Published: March 2007

ABSTRACT
During eukaryotic mRNA transcription, the synthetic activity and mRNA processing factor interactions of RNA polymerase II (RNAP II) are regulated by phosphorylation of its carboxyl-terminal domain (CTD), with modification occurring primarily on serines 2 and 5 of the CTD. We previously showed that herpes simplex virus type 1 (HSV-1) infection rapidly triggers the loss of RNAP II forms bearing serine 2 phosphorylation (Ser-2P RNAP II). Here we show that the HSV-1 immediate-early (IE) protein ICP22 is responsible for this effect during the IE phase of infection. This activity does not require the viral UL13 protein kinase, which is required for several other regulatory functions of ICP22. Additionally, we show that transient expression of ICP22 can trigger the loss of Ser-2P RNAP II in transfected cells. Thus, the ability of ICP22 to cause the loss of Ser-2 RNAP II does not require other viral factors or the context of the infected cell. Expression of the HSV-1 ICP22-related protein US1.5, which corresponds to residues 147 to 420 of ICP22, also triggers a loss of Ser-2P RNAP II in transfected cells, whereas expression of the varicella-zoster virus ICP22 homolog, ORF63, does not. Our study also provides evidence for a second, viral late gene-dependent pathway that triggers loss of Ser-2P RNAP II in infected cells, consistent with the recent work of Dai-Ju et al. (J. Q. Dai-Ju, L. Li, L. A. Johnson, and R. M. Sandri-Goldin, J. Virol. 80:3567-3581, 2006). Therefore, it appears that HSV-1 has evolved redundant mechanisms for triggering the loss of a specific phosphorylated form of RNAP II.
A Phylogenetically Conserved RNA Structure in the Poliovirus Open Reading Frame Inhibits the Antiviral Endoribonuclease RNase L
Authors: Han Jian-Qiu , Townsend Hannah L. , Jha Babal Kant , Paranjape Jayashree M. , Silverman Robert H. , Barton David J. 
Published: March 2007

ABSTRACT

RNase L is an antiviral endoribonuclease that cleaves viral mRNAs after single-stranded UA and UU dinucleotides. Poliovirus (PV) mRNA is surprisingly resistant to cleavage by RNase L due to an RNA structure in the 3C
Pro
open reading frame (ORF). The RNA structure associated with the inhibition of RNase L is phylogenetically conserved in group C enteroviruses, including PV type 1 (PV1), PV2, PV3, coxsackie A virus 11 (CAV11), CAV13, CAV17, CAV20, CAV21, and CAV24. The RNA structure is not present in other human enteroviruses (group A, B, or D enteroviruses). Coxsackievirus B3 mRNA and hepatitis C virus mRNA were fully sensitive to cleavage by RNase L. HeLa cells expressing either wild-type RNase L or a dominant-negative mutant RNase L were used to examine the effects of RNase L on PV replication. PV replication was not inhibited by RNase L activity, but rRNA cleavage characteristic of RNase L activity was detected late during the course of PV infection, after assembly of intracellular virus. Rather than inhibiting PV replication, RNase L activity was associated with larger plaques and better cell-to-cell spread. Mutations in the RNA structure associated with the inhibition of RNase L did not affect the magnitude of PV replication in HeLa cells expressing RNase L, consistent with the absence of observed RNase L activity until after virus assembly. Thus, PV carries an RNA structure in the 3C protease ORF that potently inhibits the endonuclease activity of RNase L, but this RNA structure does not prevent RNase L activity late during the course of infection, as virus assembly nears completion.
Novel Nuclear Import of Vpr Promoted by Importin α Is Crucial for Human Immunodeficiency Virus Type 1 Replication in Macrophages
Authors: Nitahara-Kasahara Yuko , Kamata Masakazu , Yamamoto Takuya , Zhang Xianfeng , Miyamoto Yoichi , Muneta Koho , Iijima Sayuki , Yoneda Yoshihiro , Tsunetsugu-Yokota Yasuko , Aida Yoko 
Published: March 2007

ABSTRACT
Monocytes/macrophages are major targets of human immunodeficiency virus type 1 (HIV-1) infection. The viral preintegration complex (PIC) of HIV-1 enters the nuclei of monocyte-derived macrophages, but very little PIC migrates into the nuclei of immature monocytes. Vpr, one of the accessory gene products of HIV-1, is essential for the nuclear import of PIC in these cells, although the role of Vpr in the entry mechanism of PIC remains to be clarified. We have shown previously that Vpr is targeted to the nuclear envelope and then transported into the nucleus by importin α alone, in an importin β-independent manner. Here we demonstrate that the nuclear import of Vpr is strongly promoted by the addition of cytoplasmic extract from macrophages but not of that from monocytes and that the nuclear import activity is lost with immunodepletion of importin α from the cytoplasmic extract. Immunoblot analysis and real-time PCR demonstrate that immature monocytes express importin α at low levels, whereas the expression of three major importin α isoforms markedly increases upon their differentiation into macrophages, indicating that the expression of importin α is required for nuclear import of Vpr. Furthermore, interaction between importin α and the N-terminal α-helical domain of Vpr is indispensable, not only for the nuclear import of Vpr but also for HIV-1 replication in macrophages. This study suggests the possibility that the binding of Vpr to importin α, preceding a novel nuclear import process, is a potential target for therapeutic intervention.
La Crosse Bunyavirus Nonstructural Protein NSs Serves To Suppress the Type I Interferon System of Mammalian Hosts
Authors: Blakqori Gjon , Delhaye Sophie , Habjan Matthias , Blair Carol D. , Sánchez-Vargas Irma , Olson Ken E. , Attarzadeh-Yazdi Ghassem , Fragkoudis Rennos , Kohl Alain , Kalinke Ulrich , Weiss Siegfried , Michiels Thomas , Staeheli Peter , Weber Friedemann 
Published: March 2007

ABSTRACT

La Crosse virus (LACV) is a mosquito-transmitted member of the
Bunyaviridae
family that causes severe encephalitis in children. For the LACV nonstructural protein NSs, previous overexpression studies with mammalian cells had suggested two different functions, namely induction of apoptosis and inhibition of RNA interference (RNAi). Here, we demonstrate that mosquito cells persistently infected with LACV do not undergo apoptosis and mount a specific RNAi response. Recombinant viruses that either express (rLACV) or lack (rLACVdelNSs) the NSs gene similarly persisted and were prone to the RNAi-mediated resistance to superinfection. Furthermore, in mosquito cells overexpressed LACV NSs was unable to inhibit RNAi against Semliki Forest virus. In mammalian cells, however, the rLACVdelNSs mutant virus strongly activated the antiviral type I interferon (IFN) system, whereas rLACV as well as overexpressed NSs suppressed IFN induction. Consequently, rLACVdelNSs was attenuated in IFN-competent mouse embryo fibroblasts and animals but not in systems lacking the type I IFN receptor. In situ analyses of mouse brains demonstrated that wild-type and mutant LACV mainly infect neuronal cells and that NSs is able to suppress IFN induction in the central nervous system. Thus, our data suggest little relevance of the NSs-induced apoptosis or RNAi inhibition for growth or pathogenesis of LACV in the mammalian host and indicate that NSs has no function in the insect vector. Since deletion of the viral NSs gene can be fully complemented by inactivation of the host's IFN system, we propose that the major biological function of NSs is suppression of the mammalian innate immune response.
Influenza Virus Infection Causes Specific Degradation of the Largest Subunit of Cellular RNA Polymerase II
Authors: Rodriguez A. , Pérez-González A. , Nieto A. 
Published: March 2007

ABSTRACT
It has been described that influenza virus polymerase associates with RNA polymerase II (RNAP II). To gain information about the role of this interaction, we explored if changes in RNAP II occur during infection. Here we show that influenza virus causes the specific degradation of the hypophosphorylated form of the largest subunit of RNAP II without affecting the accumulation of its hyperphosphorylated forms. This effect is independent of the viral strain and the origin of the cells used. Analysis of synthesized mRNAs in isolated nuclei of infected cells indicated that transcription decreases concomitantly with RNAP II degradation. Moreover, this degradation correlated with the onset of viral transcription and replication. The ubiquitin-mediated proteasome pathway is not involved in virally induced RNAP II proteolysis. The expression of viral polymerase from its cloned cDNAs was sufficient to cause the degradation. Since the PA polymerase subunit has proteolytic activity, we tested its participation in the process. A recombinant virus that encodes a PA point mutant with decreased proteolytic activity and that has defects in replication delayed the effect, suggesting that PA's contribution to RNAP II degradation occurs during infection.
APOBEC3G Multimers Are Recruited to the Plasma Membrane for Packaging into Human Immunodeficiency Virus Type 1 Virus-Like Particles in an RNA-Dependent Process Requiring the NC Basic Linker
Authors: Burnett Atuhani , Spearman Paul 
Published: March 2007

ABSTRACT
APOBEC3G is an endogenous host restriction factor that inhibits human immunodeficiency virus (HIV) replication. The antiviral activity of APOBEC3G is dependent upon its incorporation into the virus particle. The mechanisms governing incorporation of APOBEC3G into virus particles are not completely understood. In particular, some investigators have reported that APOBEC3G interacts directly with the nucleocapsid (NC) subunit of Gag, while others have found that an RNA intermediate is required for Gag-APOBEC3G interactions. In this study, we confirmed the RNA dependence of APOBEC3G packaging and performed detailed mapping of the determinants within NC that are required for virion incorporation. Surprisingly, APOBEC3G packaging did not correlate well with the presence of the N-terminal “I,” or interaction, domain within NC. Specifically, Gag constructs containing only the N-terminal region of NC packaged minimal amounts of APOBEC3G, while significant levels of APOBEC3G packaging were achieved with Gag constructs containing the basic linker region of NC. Furthermore, membrane-binding experiments revealed that the basic linker region was essential for the membrane association of APOBEC3G in a Gag-APOBEC3G complex. Fluorescence resonance energy transfer was detected between labeled APOBEC3G in cells and in particles, indicating that APOBEC3G is packaged as a multimer that is bound to packaged RNA. Regions of APOBEC3G-Gag colocalization at the plasma membrane were detected that were distinct from the punctate cytoplasmic bodies where APOBEC3G accumulates within the cell. Together, our results indicate that APOBEC3G multimerizes in an RNA-dependent fashion and that RNA-APOBEC3G multimers are recruited to the plasma membrane and subsequently into virion particles by Gag.
Role of the Sonchus Yellow Net Virus N Protein in Formation of Nuclear Viroplasms
Authors: Deng Min , Bragg Jennifer N. , Ruzin Steven , Schichnes Denise , King David , Goodin Michael M. , Jackson Andrew O. 
Published: March 2007

ABSTRACT

Sonchus yellow net virus
is a plant nucleorhabdovirus whose nucleocapsid (N), phosphoprotein (P), and polymerase (L) proteins form large viroplasms in the nuclei of infected plants (C. R. F. Martins, J. A. Johnson, D. M. Lawrence, T. J. Choi, A. Pisi, S. L. Tobin, D. Lapidus, J. D. O. Wagner, S. Ruzin, K. McDonald, and A. O. Jackson, J. Virol. 72:5669-5679, 1998). When expressed alone, the N protein localizes to the nuclei of plant and yeast (
Saccharomyces cerevisiae
) cells and the P protein is distributed throughout the cells, but coexpression of N and P results in formation of subnuclear viroplasm-like foci (M. M. Goodin, J. Austin, R. Tobias, M. Fujita, C. Morales, and A. O. Jackson, J. Virol. 75:9393-9406, 2001; M. M. Goodin, R. G. Dietzgen, D. Schichnes, S. Ruzin, and A. O. Jackson, Plant J. 31:375-383, 2002). We now show that the N protein and various fluorescent derivatives form similar subnuclear foci in plant cells and that homologous interactions mediated by a helix-loop-helix region near the amino terminus are required for formation of the foci. Mutations within the helix-loop-helix region also interfere with N- and P-protein interactions that are required for N and P colocalization in the subnuclear foci. Affinity purification of N proteins harboring single mutations within the motif revealed that Tyr40 is critical for N-N and N-P interactions. Additional in vitro binding assays also indicated that the N protein binds to yeast and plant importin α homologues, whereas mutations in the carboxy-terminal nuclear localization signal abrogate importin α binding. The P protein did not bind to the importin α homologues, suggesting that the N and P proteins use different pathways for nuclear entry. Our results in toto support a model suggesting that during infection, the N and P proteins enter the nucleus independently, that viroplasm formation requires homologous N-protein interactions, and that P protein targeting to the viroplasm requires N-P protein interactions that occur after N and P protein import into the nucleus.
In Vivo Fitness Costs of Different Gag CD8 T-Cell Escape Mutant Simian-Human Immunodeficiency Viruses for Macaques
Authors: Loh Liyen , Batten C. Jane , Petravic Janka , Davenport Miles P. , Kent Stephen J. 
Published: March 2007

ABSTRACT
The kinetics of immune escape and reversion depend upon the efficiency of CD8 cytotoxic T lymphocytes (CTL) and the fitness cost of escape mutations. Escape kinetics of three simian immunodeficiency virus Gag CTL epitopes in pigtail macaques were variable; those of KP9 and AF9 were faster than those of KW9. Kinetics of reversion of escape mutant virus to wild type upon passage to naïve major histocompatibility complex-mismatched macaques also varied. Rapid reversion occurred at KP9, gradual biphasic reversion occurred at AF9, and escape mutant KW9 virus failed to revert. The fitness impact of these mutations is KP9 > AF9 > KW9. These data provide insights into the differential utility of CTL in controlling viremia.
Coronary artery bypass surgery in elderly people
Authors: Natarajan Arun , Samadian Samad , Clark Stephen 
Published: March 2007

Abstract
An increasing number of elderly individuals are now undergoing coronary artery bypass surgery. Elderly patients, compared with patients of a younger age group, present for surgery with a greater burden of risk factors and reduced functional levels. Short-term outcomes are hence poorer in them. But symptom relief occurs in most survivors and is accompanied by excellent rates of long-term survival and a good quality of life. Therefore, an individualised risk–benefit profile must be carefully constructed by clinicians, taking into account several different factors and not just age alone. This review summarises the current concepts of coronary artery bypass surgery from the perspective of the very old.
Clinical attachments: fond farewell or new beginning? A survey of the attitudes and practice of medical consultants and international medical graduates
Authors: Wawdhane Sudhir , Saraf Vivek , Davidson Sharon , Trewby Peter 
Published: March 2007

Abstract

Objectives
To analyse the experience of clinical attachment (CA) of international medical graduates (IMGs) and consultants.

Design
Analysis of questionnaires and CVs.

Setting and participants
573 IMGs applying for a house officer post and 102 consultant physicians working in North East England.

Results
IMGs had spent a mean of 16 months unemployed, of which 3.8 months was spent on CAs. The median number of CAs was two and the average number of applications sent before obtaining a CA was 73. 90% of IMGs found their CA helpful and 57% would not take up a post without a CA first. Criticisms related to lack of responsibility, isolation and poor job prospects. 90% would apply for honorary posts if advertised. 73% had received induction at the onset of placement, but only 32% had been assessed at the end. 50% of consultants took CAs and only 4% were thinking of stopping doing so. Those without CAs blamed work pressure (43%) and pressure from their employer (23%).

Conclusions
There are deficiencies in pastoral care, the application process and assessment, but CAs are valued by IMGs and offered by half the consultants surveyed. New immigration rules will mean fewer IMGs will come to the UK, but CAs will be needed by those that do, as well by refugees and European Economic Area (EEA) graduates. The tradition of CAs for international graduates could be used to accommodate those coming to the UK on exchanges and scholarships and form part of the recently announced Medical Training Initiative for IMGs.
Paradoxical vocal cord motion disorder: past, present and future
Authors: Ibrahim Wanis H , Gheriani Heitham A , Almohamed Ahmed A , Raza Tasleem 
Published: March 2007

AbstractParadoxical vocal cord motion disorder (PVCM), also called vocal cord dysfunction, is an important differential diagnosis for asthma. The disorder is often misdiagnosed as asthma leading to unnecessary drug use, very high medical utilisation and occasionally tracheal intubation or tracheostomy. Laryngoscopy is the gold standard for diagnosis of PVCM. Speech therapy and psychotherapy are considered the cornerstone of management of this disorder. The aim of this article is to increase the awareness of PVCM among doctors, highlighting the main characteristics that distinguish it from asthma and discuss the recent medical achievements and the possible future perspectives related to this disorder.
Coupled Vibration of Unshrouded Centrifugal Compressor Impellers. Part II: Computation of Vibration Behavior
Authors: Hagelstein Dirk , Hasemann Heinrich , Rautenberg Manfred 
Published: March 2007

The increased use of small gas turbines and turbochargers in different technical fields has led to the development of highly‐loaded centrifugal compressors with extremely thin blades. Due to high rotational speed and the correspondingly high centrifugal loads, the shape of the impeller hub must also be optimized. This has led to a reduction of the thickness of the impeller disc in the outlet region. The thin parts of the impeller are very sensitive and may be damaged by the excitation of dangerous blade vibrations.Experimental investigations of coupled vibration behavior are presented in Part I of the paper. The results of these investigations were able to explain the dominance of coupling effects between the blades and the disc.Part II of the paper presented here describes finite element (FE) code computations of the vibration behavior of the blades and the complete impeller for two different impeller types – one with radial‐ending blades and the other with backswept blades. The results are able to demonstrate the influence of coupling on dynamic behavior and the high importance of careful impeller design. The computational results were found to correspond very well with the results of the experimental investigations.