bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing PCR Positivity Criterion for Detection of Herpes Simplex Virus DNA on Skin and Mucosa
Authors: Magaret Amalia S. , Wald Anna , Huang Meei-Li , Selke Stacy , Corey Larry 
Published: March 2007

ABSTRACT
In 1997, we developed a PCR assay for the detection of herpes simplex virus (HSV) DNA. Recently, we determined an optimal positivity criterion based on research specimens and a dilution study. We found that a cutoff of 50 HSV DNA copies/ml of swab specimen, a level 10-fold lower than our previous cutoff, minimizes misclassification.
Evaluation of a Novel Chromogenic Agar Medium for Isolation and Differentiation of Vancomycin-Resistant
Enterococcus faecium
and
Enterococcus faecalis
Isolates
Authors: Ledeboer Nathan A. , Das Kingshuk , Eveland Michael , Roger-Dalbert Céline , Mailler Sandrine , Chatellier Sonia , Dunne William Michael 
Published: March 2007

ABSTRACT

The development of reliable and rapid methods for the identification of patients colonized with vancomycin-resistant enterococci (VRE) is central to the containment of this agent within a hospital environment. To this end, we evaluated a prototype chromogenic agar medium (VRE-BMX; bioMérieux, Marcy l'Etoile, France) used to recover VRE from clinical specimens. This medium can also identify isolated colonies as either vancomycin-resistant
Enterococcus faecium
or
Enterococcus faecalis
, based on distinct colony colors. We compared the performance of VRE-BMX with bile esculin azide agar supplemented with vancomycin (BEAV). For this study, 147 stool samples were plated on each test medium and examined after 24 and 48 h of incubation. At 24 h, the sensitivity and specificity of each medium were as follows: BEAV, 90.9% and 89.9%, respectively; VRE-BMX, 96.4% and 96.6%, respectively. The positive predictive values (PPV) of VRE-BMX and BEAV at 24 h were 89.8% and 80.7%, respectively. VRE-BMX provided the identification of 10 isolates of vancomycin-resistant
E. faecalis
and 4 isolates of vancomycin-resistant
E. faecium
that were not recovered by BEAV. Further, VRE-BMX was capable of identifying patients colonized with both
E. faecium
and
E. faecalis
, a feature useful for infection control purposes that is not a function of BEAV. In terms of the recovery of vancomycin-resistant
E. faecium
and
E. faecalis
, the sensitivity and PPV were as follows: BEAV, 75.7% and 74.6%, respectively; VRE-BMX, 95.5% and 91.3%, respectively. In this initial evaluation, we found that VRE-BMX provided improved recovery of VRE from stool specimens, with the added advantage of being able to differentiate between vancomycin-resistant
E. faecalis
and
E. faecium
. Extending the incubation period beyond 24 h did not significantly improve the recovery of VRE and resulted in decreased specificity.
Impact of Competitive Inhibition and Sequence Variation upon the Sensitivity of Malaria PCR
Authors: Bialasiewicz Seweryn , Whiley David M. , Nissen Michael D. , Sloots Theo P. 
Published: March 2007

ABSTRACT

Real-time PCR assays for
Plasmodium
species utilizing universal and species-specific primers were compared to investigate variables influencing decreased assay sensitivity. Sequence variation in oligomer targets and competitive inhibition of dual-species templates in universal-primer mixes were found to decrease assay sensitivity.
Association between Methicillin Susceptibility and Biofilm Regulation in
Staphylococcus aureus
Isolates from Device-Related Infections
Authors: O'Neill Eoghan , Pozzi Clarissa , Houston Patrick , Smyth Davida , Humphreys Hilary , Robinson D. Ashley , O'Gara James P. 
Published: March 2007

ABSTRACT

Production of
icaADBC
-encoded polysaccharide intercellular adhesin, or poly-
N
-acetylglucosamine (PIA/PNAG), represents an important biofilm mechanism in staphylococci. We previously described a glucose-induced,
ica
-independent biofilm mechanism in four methicillin-resistant
Staphylococcus aureus
(MRSA) isolates. Here, biofilm regulation by NaCl and glucose was characterized in 114 MRSA and 98 methicillin-sensitive
S. aureus
(MSSA) isolates from diagnosed device-related infections. NaCl-induced biofilm development was significantly more prevalent among MSSA than MRSA isolates, and this association was independent of the isolate's genetic background as assessed by
spa
sequence typing. Among MSSA isolates, PIA/PNAG production correlated with biofilm development in NaCl, whereas in MRSA isolates grown in NaCl or glucose, PIA/PNAG production was not detected even though
icaADBC
was transcribed and regulated. Glucose-induced biofilm in MRSA was
ica
independent and apparently mediated by a protein adhesin(s). Experiments performed with strains that were amenable to genetic manipulation revealed that deletion of
icaADBC
had no effect on biofilm in a further six MRSA isolates but abolished biofilm in four MSSA isolates. Mutation of
sarA
abolished biofilm in seven MRSA and eight MSSA isolates. In contrast, mutation of
agr
in 13 MRSA and 8 MSSA isolates substantially increased biofilm (more than twofold) in only 5 of 21 (23%) isolates and had no significant impact on biofilm in the remaining 16 isolates. We conclude that biofilm development in MRSA is
ica
independent and involves a protein adhesin(s) regulated by SarA and Agr, whereas SarA-regulated PIA/PNAG plays a more important role in MSSA biofilm development.
High-Resolution Genotyping of
Chlamydia trachomatis
Strains by Multilocus Sequence Analysis
Authors: Klint Markus , Fuxelius Hans-Henrik , Goldkuhl Renée Röstlinger , Skarin Hanna , Rutemark Christian , Andersson Siv G. E. , Persson Kenneth , Herrmann Björn 
Published: March 2007

ABSTRACT

Genotyping of
Chlamydia trachomatis
is limited by the low sequence variation in the genome, and no adequate method is available for analysis of the spread of chlamydial infections in the community. We have developed a multilocus sequence typing (MLST) system based on five target regions and compared it with analysis of
ompA
, the single gene most extensively used for genotyping. Sequence determination of 16 reference strains, comprising all major serotypes, serotypes A to L3, showed that the number of genetic variants in the five separate target regions ranged from 8 to 16. The genetic variation in 47 clinical
C. trachomatis
isolates of representative serotypes (14 serotype D, 12 serotype E, 11 serotype G, and 10 serotype K strains) was analyzed; and the MLST system detected 32 variants, whereas 12 variants were detected by using
ompA
analysis. Specimens of the predominant serotype, serotype E, were differentiated into seven genotypes by MLST but into only two by
ompA
analysis. The MLST system was applied to
C. trachomatis
specimens from a population of men who have sex with men and was able to differentiate 10 specimens of one predominant
ompA
genotype G variant into four distinct MLST variants. To conclude, our MLST system can be used to discriminate
C. trachomatis
strains and can be applied to high-resolution molecular epidemiology.
Importance of the Penultimate Positive Charge in Mouse Hepatitis Coronavirus A59 Membrane Protein
Authors: Verma Sandhya , Lopez Lisa A. , Bednar Valerie , Hogue Brenda G. 
Published: March 2007

ABSTRACT
The coronavirus membrane (M) protein carboxy tail interacts with the nucleocapsid during virus assembly. Previous studies demonstrated that the two terminal residues are important, and the charged residue (R227) in the penultimate position in the mouse hepatitis coronavirus (MHV) A59 M protein was suggested to participate in intermolecular interactions with negative charges in the nucleocapsid (N) protein. To determine the significance of the positive charge at position 227, we substituted the arginine with lysine (K), aspartic acid (D), glutamic acid (E), or alanine (A) and studied these by reverse genetics in the context of a MHV full-length infectious clone. Viruses with wild-type phenotype were readily recovered with the K or A substitutions. In contrast, negative-charge substitutions were not tolerated as well. In all recovered R227D viruses the negative charge was replaced with heterologous residues resulting from apparent template switching during negative-strand synthesis of subgenomic RNA 7. An additional second-site compensatory V202I substitution was present in some viruses. Recovered R227E viruses had second-site changes within the M protein carboxy tail that were partially compensatory. Significantly, most of the second site changes in the R227E mutant viruses were previously shown to compensate for the removal of negative charges in the N protein. Our results strongly indicate that a positive charge is not absolutely required. It is clear that other regions within the tail must also be involved in helping mediate interactions between the M protein and the nucleocapsid.
Antiviral Antibodies Are Necessary for Control of Simian Immunodeficiency Virus Replication
Authors: Miller Christopher J. , Genescà Meritxell , Abel Kristina , Montefiori David , Forthal Donald , Bost Kristen , Li Jun , Favre David , McCune Joseph M. 
Published: March 2007

ABSTRACTTo better define the role of B cells in the control of pathogenic simian immunodeficiency virus (SIV) replication, six rhesus monkeys were depleted of B cells by intravenous infusion of rituximab (anti-CD20) 28 days and 7 days before intravaginal SIVmac239 inoculation and every 21 days thereafter until AIDS developed. Although the blood and tissues were similarly depleted of B cells, anti-SIV immunoglobulin G (IgG) antibody responses were completely blocked in only three of the six animals. In all six animals, levels of viral RNA (vRNA) in plasma peaked at 2 weeks and declined by 4 weeks postinoculation (PI). However, the three animals prevented from making an anti-SIV antibody response had significantly higher plasma vRNA levels through 12 weeks PI (P= 0.012). The remaining three B-cell-depleted animals made moderate anti-SIV IgG antibody responses, maintained moderate plasma SIV loads, and showed an expected rate of disease progression, surviving to 24 weeks PI without developing AIDS. In contrast, all three of the B-cell-depleted animals prevented from making anti-SIV IgG responses developed AIDS by 16 weeks PI (P= 0.0001). These observations indicate that antiviral antibody responses are critical in maintaining effective control of SIV replication at early time points postinfection.
Human Serum Amyloid A Protein Inhibits Hepatitis C Virus Entry into Cells
Authors: Cai Zhaohui , Cai Lei , Jiang Jieyun , Chang Kyung-Soo , van der Westhuyzen Deneys R. , Luo Guangxiang 
Published: March 2007

ABSTRACT
Serum amyloid A (SAA) is an acute-phase protein induced by a variety of inflammatory stimuli, including bacterial and viral infections. SAA was recently found to function as an opsonin for gram-negative bacteria. We report here that SAA inhibited hepatitis C virus (HCV) infection in cultured cells. SAA reduced HCV infectivity in a dose-dependent manner when added during HCV infection but not after virus entry. SAA bound HCV virions and specifically blocked HCV entry but did not affect virus attachment. These findings suggest that SAA functions as part of the host innate immune defense mechanisms against HCV infection in humans.
Intracellular Kaposi's Sarcoma-Associated Herpesvirus Load Determines Early Loss of Immune Synapse Components
Authors: Adang Laura A. , Tomescu Costin , Law Wai K. , Kedes Dean H. 
Published: March 2007

ABSTRACT
Lifelong infection is a hallmark of all herpesviruses, and their survival depends on countering host immune defenses. The human gammaherpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV) encodes an array of proteins that contribute to immune evasion, including modulator of immune recognition 2 (MIR2), an E3 ubiquitin ligase. Exogenously expressed MIR2 downregulates the surface expression of several immune synapse proteins, including major histocompatibility complex (MHC) class 1, ICAM-1 (CD54), and PECAM (CD31). Although immunofluorescence assays detect this lytic gene in only 1 to 5% of cells within infected cultures, we have found that de novo infection of naive cells leads to the downregulation of these immune synapse components in a major proportion of the population. Investigating the possibility that low levels of MIR2 are responsible for this downregulation in the context of viral infection, we found that MIR2 transduction recapitulated the patterns of surface downregulation following de novo infection and that both MIR2 promoter activation, MIR2 expression level, and immune synapse component downregulation were proportional to the concentration of KSHV added to the culture. Additionally, MIR2-specific small interfering RNA reversed the downregulation effects. Finally, using a sensitive, high-throughput assay to detect levels of the virus in individual cells, we also observed that downregulation of MHC class I and ICAM-1 correlated with intracellular viral load. Together, these results suggest that the effects of MIR2 are gene dosage dependent and that low levels of this viral protein contribute to the widespread downregulation of immune-modulating cell surface proteins during the initial stages of KSHV infection.
Structure-Dependent Modulation of Alpha Interferon Production by Porcine Circovirus 2 Oligodeoxyribonucleotide and CpG DNAs in Porcine Peripheral Blood Mononuclear Cells
Authors: Wikström Frida Hasslung , Meehan Brian M. , Berg Mikael , Timmusk Sirje , Elving Josefine , Fuxler Lisbeth , Magnusson Mattias , Allan Gordon M. , McNeilly Francis , Fossum Caroline 
Published: March 2007

ABSTRACTDNA sequences containing CpG motifs are recognized as immunomodulators in several species. Phosphodiester oligodeoxyribonucleotides (ODNs) representing sequences from the genome of porcine circovirus type 2 (PCV2) have been identified as potent inducers (ODN PCV2/5) or inhibitors (ODN PCV2/1) of alpha interferon (IFN-α) production by porcine peripheral blood mononuclear cells (poPBMCs) in vitro. In this study, the IFN-α-inducing or -inhibitory activities of specific phosphodiester ODNs were demonstrated to be dependent on their ability to form secondary structures. When a poly(G) sequence was added to a stimulatory self-complementary ODN, high levels of IFN-α were elicited, and the induction was not dependent on pretreatment with the transfecting agent Lipofectin. In addition, the IFN-α-inducing ODN required the presence of an intact CpG dinucleotide, whereas the inhibitory activity of ODN PCV2/1 was not affected by methylation or removal of the central CpG dinucleotide. Of particular significance, the IFN-α inhibition elicited by ODN PCV2/1 was only effective against induction stimulated by DNA control inducers and not RNA control inducers, indicating activity directed to TLR9 signaling. The PCV2 genome as a whole was demonstrated to induce IFN-α in cultures of poPBMCs, and the presence of immune modulatory sequences within the genome of PCV2 may, therefore, have implications with regard to the immune evasion mechanisms utilized by PCV2.
SOME SMALL CANCELLATION PROPERTIES OF RANDOM GROUPS
Authors: OLLIVIER YANN 
Published: March 2007

We work in the density model of random groups. We prove that they satisfy an isoperimetric inequality with sharp constant 1-2d depending upon the density parameter d. This implies in particular a property generalizing the ordinary C′ small cancellation condition, which could be termed "macroscopic cancellation". This also sharpens the evaluation of the hyperbolicity constant δ.As a consequence we get that the standard presentation of a random group at density d < 1/5 satisfies the Dehn algorithm and Greendlinger's lemma, and that it does not for d > 1/5.For this we establish a version of the local-global principle for hyperbolic spaces (Cartan–Hadamard–Gromov theorem) involving arbitrarily small loss in the isoperimetric constant.
STOCHASTIC MODEL PREDICTIVE CONTROL AND PORTFOLIO OPTIMIZATION
Authors: HERZOG FLORIAN , DONDI GABRIEL , GEERING HANS P. 
Published: March 2007

This paper proposes a solution method for the discrete-time long-term dynamic portfolio optimization problem with state and asset allocation constraints. We use the ideas of Model Predictive Control (MPC) to solve the constrained stochastic control problem. MPC is a solution technique which was developed to solve constrained optimal control problems for deterministic control applications. MPC solves the optimal control problem with a receding horizon where a series of consecutive open-loop optimal control problems is solved. The aim of this paper is to develop an MPC approach to the problem of long-term portfolio optimization when the expected returns of the risky assets are modeled using a factor model based on stochastic Gaussian processes. We prove that MPC is a suboptimal control strategy for stochastic systems which uses the new information advantageously and thus is better than the pure optimal open-loop control. For the open-loop optimal control optimization, we derive the conditional portfolio distribution and the corresponding conditional portfolio mean and variance. The mean and the variance depend on future decision about the asset allocation. For the dynamic portfolio optimization problem, we consider constraints on the asset allocation as well as probabilistic constraints on the attainable values of the portfolio wealth. We discuss two different objectives, a classical mean–variance objective and the objective to maximize the probability of exceeding a predetermined value of the portfolio. The dynamic portfolio optimization problem is stated, and the solution via MPC is explained in detail. The results are then illustrated in a case study.
THE MARKET REACTION TO STOCK SPLITS — EVIDENCE FROM INDIA
Authors: MISHRA A. K. 
Published: March 2007

Stock splits are a relatively new phenomenon in the Indian context. This paper examines the market effect of stock splits on stock price, return, volatility, and trading volume around the split ex-dates for a sample of stock splits undertaken in the Indian stock market over the period 1999–2005. The traditional view of stock splits as cosmetic transactions that simply divide the same pie into more slices is inconsistent with the significant wealth effect associated with the announcement of a stock split. However, the empirical evidence confirms a negative effect on price and return of stock splits. The overall cumulative abnormal returns after the split are negative. These results suggest that stock splits have induced the market to revise its optimistic valuation about future firm performance, rejecting signaling hypothesis to which splits convey positive information to markets. Hence, stock splits have reduced the wealth of the shareholders. The results also show that presence of a positive effect on volatility and trading volume following the split events, thus suggesting that split events enhance liquidity.
Shared heritage and differing values in child welfare services in Scotland and North Carolina
Authors: Beerman Daniel R. , Smith Mark 
Published: March 2007

English The unique shared history of Scotland and North Carolina offers fertile ground for cross-cultural comparison of child welfare approaches. This preliminary study yields a rich scholarly and structural contrast, which allows for deeper understanding of how cultural differences affect the delivery of child welfare services. French La situation historique unique de l'Écosse et de la Caroline du Nord qui ont un passé commun offre un terrain fertile pour l'é tude comparative des diffé rences interculturelles en ce qui a trait aux approches en matiè re de protection de l'enfance. L'é tude pré liminaire ré vè le un riche contraste sur les plans du savoir et des structures, ce qui permet de mieux saisir l'impact des diffé rences culturelles sur la livraison des services de protection de l'enfance. Spanish La historia única compartida entre Escocia y Carolina del Norte ofrece un terreno fé rtil para las aproximaciones a la comparación transcultural en el bienestar infantil. Este estudio preliminar produce un rico contraste tanto estructural como en conocimientos, el cual permite un entendimiento más profundo sobre la manera en que las diferencias culturales impactan la adjudicación de los servicios de bienestar infantil.
Responding to the war with Iraq among social work faculty in the USA, UK and Australia
Authors: Davis Cindy , Cummings Sherry , MacMaster Samuel , Thompkins Albert 
Published: March 2007

English The current study explored how social work educators responded to the war with Iraq. The majority of respondents felt that faculty had a responsibility to educate students about the war. However, more Australian respondents felt that social work faculty had a responsibility to advocate for or against the war. French La présente étude explore la réponse des professeurs en travail social à la guerre en Irak. La majoritédes répondants soutiennent que leur facultéa la responsabilitéde renseigner les étudiants au sujet de la guerre. Toutefois, les répondants australiens soutiennent en plus grand nombre que la facultéa aussi la responsabilitéde justifier un positionnement en faveur ou à l'encontre de la guerre. Spanish El presente estudio explorócómo reaccionaron los educadores de trabajo social frente a la guerra con Iraq. La mayoría de los entrevistados expresóque la facultad tenía la responsabilidad de educar a los estudiantes acerca de la guerra. Sin embargo, muchos de los entrevistados australianos manifestaron que la facultad de trabajo social tenía una responsabilidad de abogar por la guerra o en contra de ella.
Developing social work in Vietnam
Authors: Hugman Richard , Lan Nguyen Thi Thai , Hong Nguyen Thuy 
Published: March 2007

English There has been a growing recognition in Vietnam (since the 1986 economic reforms) that professional social work is required to respond effectively to social problems. This article presents findings from a government and UNICEF-sponsored study undertaken to examine developments in social work. These are considered in relation to the profession globally. French Au Vietnam, on reconnaît de plus en plus, depuis les réformes é conomiques de 1986, que le travail social professionnel est né cessaire pour ré pondre adé quatement aux problèmes sociaux. Cet article pré sente les ré sultats d'une é tude commandité e par le gouvernement et l'UNICEF sur l'é volution du travail social. Les ré sultats sont mis en perspective par rapport à la profession dans son ensemble. Spanish Ha habido un reconocimiento creciente en Vietnam (a partir de las reformas económicas de 1986) en el sentido de que el trabajo social profesional es necesario para responder efectivamente a los problemas sociales. Este artículo presenta los hallazgos de un estudio patrocinado por el gobierno y la UNICEF, realizado para examinar los desarrollos en trabajo social. Estos son considerados en relación con la profesión en una perspectiva global.