bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation of Proinflammatory and Anti-Inflammatory Cytokine Levels with Histopathological Changes in an Adult Mouse Lung Model ofCampylobacter jejuniInfection
Authors: Al-Banna Nadia , Raghupathy Raj , Albert M. John 
Published: October 2008

ABSTRACTCampylobacter jejuniis a major cause of diarrhea in humans. A mouse lung model of infection was previously established forC. jejuni. We used this model to study cytokine production in the lungs and correlated it with pathological changes.C. jejunistrain 81-176 or sterile phosphate-buffered saline was intranasally inoculated into adult BALB/c mice. The levels of proinflammatory cytokines (gamma interferon, tumor necrosis factor alpha, interleukin-1β [IL-1β], IL-2) and anti-inflammatory cytokines (IL-4, IL-10), in addition to those of IL-6, were assessed on days 1, 3, and 5 postinfection by enzyme-linked immunosorbent assay, and the ratios of proinflammatory cytokines to anti-inflammatory cytokines were calculated. Since IL-6 is unique in that it is both a proinflammatory cytokine and a TH2 cytokine, it was considered to be both in the determination of these ratios. The significance of the cytokine levels and ratios were determined by the Mann-Whitney U test (P≤ 0.05). The induction of proinflammatory cytokines in the lungs of infected mice, as indicated by the cytokine levels and ratios, coincided with the accumulation of neutrophils and activated macrophages, in addition to the clearance of the bacterial load and bacteriumlike structures that we have previously shown in the same groups of mice. This was followed by increased levels of anti-inflammatory cytokines and the resolution of inflammation and pathology in the lungs. This study demonstrates the dynamics of cytokine production and their correlation with tissue inflammation and the resolution of infection. This model is useful for further studies of the pathogenesis ofC. jejuniinfection and vaccine evaluation.
Genetic Relatedness of
Clostridium difficile
Isolates from Various Origins Determined by Triple-Locus Sequence Analysis Based on Toxin Regulatory Genes
tcdC, tcdR
, and
cdtR
Authors: Bouvet Philippe J. M. , Popoff Michel R. 
Published: October 2008

ABSTRACT

A triple-locus nucleotide sequence analysis based on toxin regulatory genes
tcdC, tcdR
and
cdtR
was initiated to assess the sequence variability of these genes among
Clostridium difficile
isolates and to study the genetic relatedness between isolates. A preliminary investigation of the variability of the
tcdC
gene was done with 57 clinical and veterinary isolates. Twenty-three isolates representing nine main clusters were selected for
tcdC, tcdR
, and
cdtR
analysis. The numbers of alleles found for
tcdC, tcdR
and
cdtR
were nine, six, and five, respectively. All strains possessed the
cdtR
gene except toxin A-negative toxin B-positive variants. All but one binary toxin CDT-positive isolate harbored a deletion (>1 bp) in the
tcdC
gene. The combined analyses of the three genes allowed us to distinguish five lineages correlated with the different types of deletion in
tcdC
, i.e., 18 bp (associated or not with a deletion at position 117), 36 bp, 39 bp, and 54 bp, and with the wild-type
tcdC
(no deletion). The
tcdR
and
tcdC
genes, though located within the same pathogenicity locus, were found to have evolved separately. Coevolution of the three genes was noted only with strains harboring a 39-bp or a 54-bp deletion in
tcdC
that formed two homogeneous, separate divergent clusters. Our study supported the existence of the known clones (PCR ribotype 027 isolates and toxin A-negative toxin B-positive
C. difficile
variants) and evidence for clonality of isolates with a 39-bp deletion (toxinotype V, PCR ribotype 078) that are frequently isolated worldwide from human infections and from food animals.
Pyogenic Flexor Tenosynovitis Associated with
Cellulosimicrobium cellulans
Authors: Tucker Joseph D. , Montecino Rafael , Winograd Jonathan M. , Ferraro MaryJane , Michelow Ian C. 
Published: October 2008

ABSTRACT

Cellulosimicrobium cellulans
, formerly known as
Oerskovia xanthineolytica
, is a rare human pathogen, often in association with a foreign body. A case of pyogenic flexor tenosynovitis associated with
C. cellulans
in an immunocompetent boy is described, underlining the importance of prompt surgical and microbiologic evaluation.
Comparison between the Standardized Clinical and Laboratory Standards Institute M38-A2 Method and a 2,3-Bis(2-Methoxy-4-Nitro-5-[(Sulphenylamino)Carbonyl]-2
H
-Tetrazolium Hydroxide- Based Method for Testing Antifungal Susceptibility of Dermatophytes
Authors: Shehata Atef S. , Mukherjee Pranab K. , Ghannoum Mahmoud A. 
Published: October 2008

ABSTRACT

In this study, we determined the utility of a 2,3-bis(2-methoxy-4-nitro-5-[(sulfenylamino)carbonyl]-2
H
-tetrazolium hydroxide (XTT)-based assay for determining antifungal susceptibilities of dermatophytes to terbinafine, ciclopirox, and voriconazole in comparison to the Clinical and Laboratory Standards Institute (CLSI) M38-A2 method. Forty-eight dermatophyte isolates, including
Trichophyton rubrum
(
n
= 15),
Trichophyton mentagrophytes
(
n
= 7),
Trichophyton tonsurans
(
n
= 11), and
Epidermophyton floccosum
(
n
= 13), and two quality control strains, were tested. In the XTT-based method, MICs were determined spectrophotometrically at 490 nm after addition of XTT and menadione. For the CLSI method, the MICs were determined visually. With
T. rubrum
, the XTT assay revealed MIC ranges of 0.004 to >64 μg/ml, 0.125 to 0.25 μg/ml, and 0.008 to 0.025 μg/ml for terbinafine, ciclopirox, and voriconazole, respectively. Similar MIC ranges were obtained against
T. rubrum
by using the CLSI method. Additionally, when tested with
T. mentagrophytes
,
T. tonsurans
, and
E. floccosum
isolates, the XTT and CLSI methods resulted in comparable MIC ranges. Both methods revealed similar lowest drug concentrations that inhibited 90% of the isolates for the majority of tested drug-dermatophyte combinations. The levels of agreement within 1 dilution between both methods were as follows: 100% with terbinafine, 97.8% with ciclopirox, and 89.1% with voriconazole. However, the agreement within 2 dilutions between these two methods was 100% for all tested drugs. Our results revealed that the XTT assay can be a useful tool for antifungal susceptibility testing of dermatophytes.
Rapid Differentiation of Methicillin-Resistant
Staphylococcus aureus
and Methicillin-Susceptible
Staphylococcus aureus
from Blood Cultures by Use of a Direct Cefoxitin Disk Diffusion Test
Authors: Bennett Kelly , Sharp Susan E. 
Published: October 2008

ABSTRACT

A total of 276 blood culture bottles with
Staphylococcus aureus
were tested by direct cefoxitin disk diffusion testing; 105 (38.1%) had zone sizes of ≤17 mm (all 105 had methicillin-resistant
S. aureus
[MRSA]), 18 (6.5%) had zone sizes that measured 18 mm (17 had MRSA and 1 had methicillin-susceptible
S. aureus
[MSSA]), 8 (2.9%) had zone sizes that measured 19 mm (6 had MRSA and 2 had MSSA), 8 (2.9%) had zone sizes that measured 20 mm (6 had MRSA and 2 had MSSA), and 137 (49.6%) had zone sizes of ≥21 mm (all 137 had MSSA). Detection of MRSA/MSSA in blood cultures could be reported 10 to 24 h earlier for 88% of cultures with total accuracy.
Genetic Diversity of Isoniazid-Resistant
Mycobacterium tuberculosis
Isolates Collected in Poland and Assessed by Spoligotyping
Authors: Augustynowicz-Kopeć Ewa , Jagielski Tomasz , Zwolska Zofia 
Published: October 2008

ABSTRACT

The genetic compositions of 71 isoniazid-resistant
Mycobacterium tuberculosis
strains from Poland were determined by spoligotyping. Nearly 80% of the isolates belonged to either the T or the Haarlem family. The genotypic diversity was largely due to variation within those families. The scarcity of imported genotypes suggested that the
M. tuberculosis
population studied has an endemic nature.
Analytical and Clinical Sensitivity of the 3M Rapid Detection Influenza A+B Assay
Authors: Dale Suzanne E. , Mayer Christine , Mayer Marie C. , Menegus Marilyn A. 
Published: October 2008

ABSTRACT
The performance of the 3M rapid detection influenza A+B (3M flu) assay was compared to the performance of other immunochromatographic assays. The clinical and analytical performance of the 3M flu assay was superior to that of BinaxNOW and Directigen EZ assays and equivalent to that of the QuickVue assay. The 3M flu assay offers an objective output and direct linkage to laboratory information systems.
Excretion of Human Immunodeficiency Virus Type 1 through Polarized Epithelium by Immunoglobulin A
Authors: Wright Alison , Lamm Michael E. , Huang Yung T. 
Published: October 2008

ABSTRACTHuman immunodeficiency virus (HIV) is transmitted primarily sexually across mucosal surfaces. After infection, HIV propagates initially in the lamina propria below the polarized epithelium and causes extensive destruction of mucosal T cells. Immunoglobulin A (IgA) antibodies, produced in the lamina propria and then transcytosed across the mucosal epithelium into the lumen, can be the first line of immune defense against HIV. Here, we used IgA monoclonal antibodies against HIV envelope proteins to investigate the abilities of polarized primate and human epithelial cells to excrete HIV virions from the basolateral to the apical surface via polymeric Ig receptor (pIgR)-mediated binding and the internalization of HIV-IgA immune complexes. African green monkey kidney cells expressing pIgR demonstrated HIV excretion that was dependent on the IgA concentration and the exposure time. Matched IgG antibodies with the same variable regions as the IgA antibodies and IgA antibodies to non-HIV antigens had no HIV excretory function. A mixture of two IgA anti-bodies against gp120 and gp41 showed a synergistic increase in the level of HIV excreted. The capacity for HIV excretion correlated with the ability of IgA antibodies to bind HIV and of the resulting immune complexes to bind pIgR. Consistent with the epithelial transcytosis of HIV-IgA immune complexes, the colocalization of HIV proteins and HIV-specific IgA was detected intracellularly by confocal microscopy. Our results suggest the potential of IgA antibodies to excrete HIV from mucosal lamina propria, thereby decreasing the viral burden, access to susceptible cells, and the chronic activation of the immune system.
Human T-Cell Lymphotropic Virus Type 1 Nucleocapsid Protein-Induced Structural Changes in Transactivation Response DNA Hairpin Measured by Single-Molecule Fluorescence Resonance Energy Transfer
Authors: Darugar Qusai , Kim Hannah , Gorelick Robert J. , Landes Christy 
Published: October 2008

ABSTRACT
Time-resolved single-molecule fluorescence spectroscopy was used to study the human T-cell lymphotropic virus type 1 (HTLV-1) nucleocapsid protein (NC) chaperone activity compared to that of the human immunodeficiency virus type 1 (HIV-1) NC protein. HTLV-1 NC contains two zinc fingers, each having a CCHC binding motif similar to HIV-1 NC. HIV-1 NC is required for recognition and packaging of the viral RNA and is also a nucleic acid chaperone protein that facilitates nucleic acid restructuring during reverse transcription. Because of similarities in structures between the two retroviruses, we have used single-molecule fluorescence energy transfer to investigate the chaperoning activity of the HTLV-1 NC protein. The results indicate that the HTLV-1 NC protein induces structural changes by opening the transactivation response (TAR) DNA hairpin to an even greater extent than HIV-1 NC. However, unlike HIV-1 NC, HTLV-1 NC does not chaperone the strand-transfer reaction involving TAR DNA. These results suggest that, despite its effective destabilization capability, HTLV-1 NC is not as effective at overall chaperone function as is its HIV-1 counterpart.
S
-Adenosyl Homocysteine-Induced Hyperpolyadenylation of Vesicular Stomatitis Virus mRNA Requires the Methyltransferase Activity of L Protein
Authors: Galloway Summer E. , Wertz Gail W. 
Published: October 2008

ABSTRACT

There are many unique aspects of vesicular stomatitis virus (VSV) transcription. In addition to its unusual mRNA capping and methyltransferase mechanisms, the addition of
S
-adenosyl homocysteine (SAH), which is the by-product and competitive inhibitor of
S
-adenosyl methionine (SAM)-mediated methyltransferase reactions, leads to synthesis of poly(A) tails on the 3′ end of VSV mRNAs that are 10- or 20-fold longer than normal. The mechanism by which this occurs is not understood, since it has been shown that productive transcription is not dependent on 5′ cap methylation and full-length VSV mRNAs can be synthesized in the absence of SAM. To investigate this unusual phenotype, we assayed the effects of SAH on transcription using a panel of recombinant viruses that contained mutations in domain VI of the VSV L protein. The L proteins we investigated displayed a range of 5′ cap methyltransferase activities. In the present study, we show that the ability of the VSV L protein to catalyze methyl transfer correlates with its sensitivity to SAH with respect to polyadenylation, thereby indicating an intriguing connection between 5′ and 3′ end mRNA modifications. We also identified an L protein mutant that hyperpolyadenylates mRNA irrespective of the presence or absence of exogenous SAH. Further, the data presented here show that the wild-type L protein hyperpolyadenylates a percentage of VSV mRNAs in infected cells as well as in vitro.
Determinants of RNA-Dependent RNA Polymerase (In)fidelity Revealed by Kinetic Analysis of the Polymerase Encoded by a Foot-and-Mouth Disease Virus Mutant with Reduced Sensitivity to Ribavirin
Authors: Arias Armando , Arnold Jamie J. , Sierra Macarena , Smidansky Eric D. , Domingo Esteban , Cameron Craig E. 
Published: October 2008

ABSTRACT
A mutant poliovirus (PV) encoding a change in its polymerase (3Dpol) at a site remote from the catalytic center (G64S) confers reduced sensitivity to ribavirin and forms a restricted quasispecies, because G64S 3Dpol is a high-fidelity enzyme. A foot-and-mouth disease virus (FMDV) mutant that encodes a change in the polymerase catalytic site (M296I) exhibits reduced sensitivity to ribavirin without restricting the viral quasispecies. In order to resolve this apparent paradox, we have established a minimal kinetic mechanism for nucleotide addition by wild-type (WT) FMDV 3Dpol that permits a direct comparison to PV 3Dpol as well as to FMDV 3Dpol derivatives. Rate constants for correct nucleotide addition were on par with those of PV 3Dpol, but apparent binding constants for correct nucleotides were higher than those observed for PV 3Dpol. The A-to-G transition frequency was calculated to be 1/20,000, which is quite similar to that calculated for PV 3Dpol. The analysis of FMDV M296I 3Dpol revealed a decrease in the calculated ribavirin incorporation frequency (1/8,000) relative to that (1/4,000) observed for the WT enzyme. Unexpectedly, the A-to-G transition frequency was higher (1/8,000) than that observed for the WT enzyme. Therefore, FMDV selected a polymerase that increases the frequency of the misincorporation of natural nucleotides while specifically decreasing the frequency of the incorporation of ribavirin nucleotide. These studies provide a mechanistic framework for understanding FMDV 3Dpol structure-function relationships, provide the first direct analysis of the fidelity of FMDV 3Dpol in vitro, identify the β9-α11 loop as a (in)fidelity determinant, and demonstrate that not all ribavirin-resistant mutants will encode high-fidelity polymerases.
A Linear Relationship between Fitness and the Logarithm of the Critical Bottleneck Size in Vesicular Stomatitis Virus Populations
Authors: Novella Isabel S. , Dutta Ranendra N. , Wilke Claus O. 
Published: October 2008

ABSTRACTWe explored the relationship between fitness change and population size during transmission in vesicular stomatitis populations of very high fitness. The results show a linear correlation between the logarithm of the critical bottleneck size (population size at which there are no significant fitness changes after 20 passages) and the initial fitness of the population. In addition, limits to fitness increases during large-population passages of very-high-fitness strains were abolished by increasing the population size during transmission, indicating that beneficial variation is still available in these populations.
Early Steps of the Virus Replication Cycle Are Inhibited in Prostate Cancer Cells Resistant to Oncolytic Vesicular Stomatitis Virus
Authors: Carey Brooke L. , Ahmed Maryam , Puckett Shelby , Lyles Douglas S. 
Published: October 2008

ABSTRACT
Vesicular stomatitis virus (VSV) is currently being studied as a candidate oncolytic virus for tumor therapies due to its potent tumoricidal activity. Previous studies have demonstrated that VSV selectively infects tumor cells due to defects in their antiviral pathways. These defects make them more susceptible to VSV-induced killing than normal cells. However, some cancer cells display differential sensitivity to VSV. Specifically, LNCaP prostate cancer cells are sensitive to infection with VSV, while PC3 prostate cancer cells are relatively resistant to VSV. This suggests that tumor cells vary in the extent to which they develop defects in antiviral pathways and, thus, permit virus replication. The goal of these studies was to identify the step(s) of the viral replication cycle that is inhibited in PC3 cells. Results showed that although attachment of VSV was not significantly different among cell types, penetration was delayed by 10 to 30 min in PC3 cells relative to LNCaP cells. Primary transcription was delayed by 6 to 8 h in PC3 cells relative to LNCaP cells. Similarly, both secondary transcription and viral protein synthesis rates were delayed by about 6 to 8 h. The progressively increasing delay suggests that more than one step is affected in PC3 cells. Analysis of cellular gene expression showed that in contrast to LNCaP cells, PC3 cells constitutively expressed numerous antiviral gene products, which may enhance their resistance to VSV. These data indicate that the use of VSV for oncolytic virus therapy for prostate tumors may require prescreening of tumors for their level of susceptibility.
Cyclophilin A-Dependent Restriction of Human Immunodeficiency Virus Type 1 Capsid Mutants for Infection of Nondividing Cells
Authors: Qi Mingli , Yang Ruifeng , Aiken Christopher 
Published: October 2008

ABSTRACT
Among retroviruses, lentiviruses are unusual in their ability to efficiently infect both dividing and nondividing cells, such as activated T cells and macrophages, respectively. Recent studies implicate the viral capsid protein (CA) as a key determinant of cell-cycle-independent infection by human immunodeficiency virus type 1 (HIV-1). We investigated the effects of the host cell protein cyclophilin A (CypA), which binds to HIV-1 CA, on HIV-1 infection of nondividing cells. The HIV-1 CA mutants A92E, T54A, and R132K were impaired for infection of aphidicolin-arrested HeLa cells, but not HOS cells. The mutants synthesized normal quantities of two-long-terminal-repeat circles in arrested HeLa cells, indicating that the mutant preintegration complexes can enter the nuclei of both dividing and nondividing cells. The impaired infectivity of the CA mutants on both dividing and nondividing HeLa cells was relieved by either pharmacological or genetic disruption of the CypA-CA interaction or by RNA interference-mediated depletion of CypA expression in target cells. A second-site suppressor of the CypA-restricted phenotype also restored the ability of CypA-restricted HIV-1 mutants to infect growth-arrested HeLa cells. These results indicate that CypA-restricted mutants are specifically impaired at a step between nuclear import and integration in nondividing HeLa cells. This study reveals a novel target cell-specific restriction of HIV-1 CA mutants in nondividing cells that is dependent on CypA-CA interactions.
Engineering Viable Foot-and-Mouth Disease Viruses with Increased Thermostability as a Step in the Development of Improved Vaccines
Authors: Mateo Roberto , Luna Eva , Rincón Verónica , Mateu Mauricio G. 
Published: October 2008

ABSTRACTWe have rationally engineered foot-and-mouth disease virus to increase its stability against thermal dissociation into subunits without disrupting the many biological functions needed for its infectivity. Amino acid side chains located near the capsid intersubunit interfaces and either predicted or found to be dispensable for infectivity were replaced by others that could establish new disulfide bonds or electrostatic interactions between subunits. Two engineered viruses were normally infectious, genetically stable, and antigenically indistinguishable from the natural virus but showed substantially increased stability against irreversible dissociation. Electrostatic interactions mediated this stabilizing effect. For foot-and-mouth disease virus and other viruses, some evidence had suggested that an increase in virion stability could be linked to an impairment of infectivity. The results of the present study show, in fact, that virion thermostability against dissociation into subunits may not be selectively constrained by functional requirements for infectivity. The thermostable viruses obtained, and others similarly engineered, could be used for the production, using current procedures, of foot-and-mouth disease vaccines that are less dependent on a faultless cold chain. In addition, introduction of those stabilizing mutations in empty (nucleic acid-free) capsids could facilitate the production of infection-risk-free vaccines against the disease, one of the economically most important animal diseases worldwide.
Identification of a Residue in Hepatitis C Virus E2 Glycoprotein That Determines Scavenger Receptor BI and CD81 Receptor Dependency and Sensitivity to Neutralizing Antibodies
Authors: Grove Joe , Nielsen Søren , Zhong Jin , Bassendine Margaret F. , Drummer Heidi E. , Balfe Peter , McKeating Jane A. 
Published: October 2008

ABSTRACT
Hepatitis C virus (HCV) infection is dependent on at least three coreceptors: CD81, scavenger receptor BI (SR-BI), and claudin-1. The mechanism of how these molecules coordinate HCV entry is unknown. In this study we demonstrate that a cell culture-adapted JFH-1 mutant, with an amino acid change in E2 at position 451 (G451R), has a reduced dependency on SR-BI. This altered receptor dependency is accompanied by an increased sensitivity to neutralization by soluble CD81 and enhanced binding of recombinant E2 to cell surface-expressed and soluble CD81. Fractionation of HCV by density gradient centrifugation allows the analysis of particle-lipoprotein associations. The cell culture-adapted mutation alters the relationship between particle density and infectivity, with the peak infectivity occurring at higher density than the parental virus. No association was observed between particle density and SR-BI or CD81 coreceptor dependence. JFH-1 G451R is highly sensitive to neutralization by gp-specific antibodies, suggesting increased epitope exposure at the virion surface. Finally, an association was observed between JFH-1 particle density and sensitivity to neutralizing antibodies (NAbs), suggesting that lipoprotein association reduces the sensitivity of particles to NAbs. In summary, mutation of E2 at position 451 alters the relationship between particle density and infectivity, disrupts coreceptor dependence, and increases virion sensitivity to receptor mimics and NAbs. Our data suggest that a balanced interplay between HCV particles, lipoprotein components, and viral receptors allows the evasion of host immune responses.