bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acquisition of Avian PathogenicEscherichia coliPlasmids by a CommensalE. coliIsolate Enhances Its Abilities To Kill Chicken Embryos, Grow in Human Urine, and Colonize the Murine Kidney
Authors: Skyberg Jerod A. , Johnson Timothy J. , Johnson James R. , Clabots Connie , Logue Catherine M. , Nolan Lisa K. 
Published: October 2006

ABSTRACTWe have found an avian pathogenicEscherichia coli(APEC) plasmid, pAPEC-O2-ColV, which contains many of the genes associated with APEC virulence and also shows similarity in content to a plasmid and pathogenicity island of human uropathogenicE. coli(UPEC). To test the possible role of this plasmid in virulence, it was transferred by conjugation along with a large R plasmid, pAPEC-O2-R, into a commensal avianE. colistrain. The transconjugant was compared to recipient strain NC, UPEC strain HE300, and donor strain APEC O2 using various assays, including lethality for chicken embryos, growth in human urine, and ability to cause urinary tract infection in mice. The transconjugant killed significantly more chicken embryos than did the recipient. In human urine, APEC O2 grew at a rate equivalent to that of UPEC strain HE300, and the transconjugant showed significantly increased growth compared to the recipient. The transconjugant also significantly outcompeted the recipient in colonization of the murine kidney. These findings suggest that APEC plasmids, such as pAPEC-O2-ColV, contribute to the pathogenesis of avian colibacillosis. Moreover, since avianE. coliand their plasmids may be transmitted to humans, evaluation of APEC plasmids as possible reservoirs of urovirulence genes for human UPEC may be warranted.
Mice Naturally Resistant to
Yersinia pestis
Δ
pgm
Strains Commonly Used in Pathogenicity Studies
Authors: Congleton Yasemin H. K. , Wulff Christine R. , Kerschen Edward J. , Straley Susan C. 
Published: October 2006

ABSTRACT

We report that females of some substrains of inbred mouse strain 129 are resistant to systemic plague due to conditionally virulent Δ
pgm
strains of
Yersinia pestis
; however, fully virulent
Y. pestis
is not attenuated in these mice. Therefore, these mice offer a powerful system in which to map in parallel host resistance traits and opposing bacterial virulence properties for plague.
Comparison of the Serological Responses toMoraxella catarrhalisImmunoglobulin D-Binding Outer Membrane Protein and the Ubiquitous Surface Proteins A1 and A2
Authors: Tan Thuan Tong , Christensen Jens Jørgen , Dziegiel Morten Hanefeld , Forsgren Arne , Riesbeck Kristian 
Published: October 2006

ABSTRACTMoraxella catarrhalisimmunoglobulin D-binding protein (MID) is a complex antigen with unique immunoglobulin D (IgD)-binding, adhesion, and hemagglutination properties. Previous studies have shown that antibodies raised against MID764-913in rabbits inhibitedM. catarrhalisadhesion to human alveolar epithelial cells, and immunization with MID764-913resulted in an increased pulmonary clearance in a murine model. Strong immune responses against MID have also consistently been shown in humans. Here, the MID-specified IgG responses were compared to those of ubiquitous surface proteins A1 and A2 (UspA1/A2) using a series of recombinant fragments that spanned all three proteins. Sera were obtained from young children, aged 6 months to 1 year (n= 8) and 2 to 3 years (n= 15), and healthy adults (n= 16). Acute- and convalescent-phase sera from chronic obstructive pulmonary disease (COPD) patients withM. catarrhalisinfective exacerbations (n= 23) were also analyzed. Young children, who are at risk ofM. catarrhalisinfection, had low levels of anti-MID and anti-UspA1/A2 antibodies. Healthy adults and the majority of COPD patients (16/23) had high levels of antibodies directed against, among others, the adhesive domain of MID and the fibronectin- and C3-binding domains of UspA1/A2. Among eight COPD patients in whom a rise in antibody levels could be detected, these functional domains were also the main regions targeted by the antibodies. In addition, human IgG directed against MID was bactericidal and anti-MID antibodies were additive to antibodies targeting UspA1/A2. Hence, the functional domains in these three antigens may have significant potential in a future vaccine againstM. catarrhalis.
Alpha-Toxin ofClostridium perfringensIs Not an Essential Virulence Factor in Necrotic Enteritis in Chickens
Authors: Keyburn Anthony L. , Sheedy Scott A. , Ford Mark E. , Williamson Mark M. , Awad Milena M. , Rood Julian I. , Moore Robert J. 
Published: October 2006

ABSTRACTTheClostridium perfringensalpha-toxin has previously been implicated as the major virulence factor in necrotic enteritis in chickens, although definitive proof has not been reported. In this study an alpha-toxin mutant was constructed in a virulent chicken isolate and shown to retain full virulence in a chicken disease model. These results demonstrated that alpha-toxin is not an essential virulence factor in the pathogenesis of necrotic enteritis in chickens.
Novel Surface Structures Are Associated with the Adhesion of
Actinobacillus actinomycetemcomitans
to Collagen
Authors: Ruiz Teresa , Lenox Christopher , Radermacher Michael , Mintz Keith P. 
Published: October 2006

ABSTRACT

Actinobacillus actinomycetemcomitans
is a gram-negative, facultative, anaerobic bacterium that colonizes the human oral cavity and the upper respiratory tract. This bacterium is strongly associated with localized aggressive periodontitis and adult periodontitis and is the causative agent for other serious systemic infections. Recently, we have identified a protein, EmaA (extracellular matrix protein adhesin A), that mediates the adhesion of
A. actinomycetemcomitans
to collagen. The conserved sequence and predicted secondary structure suggest that EmaA is an orthologue of the
Yersinia enterocolitica
adhesin YadA. Electron microscopy examinations of
A. actinomycetemcomitans
have identified antenna-like protrusions associated with the surface of the bacterium. These structures are absent on
emaA
mutant strains and can be restored by transformation of the mutant strain with
emaA
in
trans
. The loss of these structures is associated with a decrease in the binding of this bacterium to collagen. The antenna-like structures are composed of a long rod that terminates in an ellipsoidal head region. The analysis of these structures using image processing techniques has provided an initial estimate of the overall dimensions, which suggests that the appendages are oligomeric structures formed by either three or four subunits. Together, the data suggest that
emaA
is required for the expression of novel appendages on the surface of
A. actinomycetemcomitans
that mediate the adhesion of the bacterium to collagen.
Immunostimulatory Activity of RecombinantMycobacterium bovisBCG That Secretes Major Membrane Protein II ofMycobacterium leprae
Authors: Makino Masahiko , Maeda Yumi , Inagaki Katsuya 
Published: October 2006

ABSTRACTWe previously demonstrated that major membrane protein II (MMP-II) is one of the immunodominant antigens (Ags) ofMycobacterium lepraecapable of activating T cells through Toll-like receptor 2. Based on the observation thatMycobacterium bovisBCG secreting a 30-kDa protein offered better protection against tuberculosis, we constructed a recombinant BCG strain (BCG-SM) that secretes MMP-II to improve the potency of BCG against leprosy. The secreted MMP-II protein from BCG-SM stimulated monocyte-derived dendritic cells (DC) to produce interleukin-12. DC infected with BCG-SM expressed MMP-II on their surfaces, and MMP-II expression was suppressed by the pretreatment of DC with chloroquine. These results indicated that secreted MMP-II was processed by DC for higher expression levels on their surfaces. In addition, BCG-SM phenotypically activated DC and induced higher expression levels of major histocompatibility complex, CD86, and CD83 Ags on DC than did vector control BCG (BCG-pMV). The DC infected with BCG-SM more efficiently stimulated naïve and memory CD4+T cells and memory CD8+T cells to produce gamma interferon than did those infected with BCG-pMV. However, naïve CD8+T cells were significantly activated only when they were stimulated with BCG-SM-infected DC. When CD8+T cells were cocultured with BCG-SM-infected DC, the proportion of perforin-producing T cells was significantly higher than that in cells cocultured with BCG-pMV-infected DC. Moreover, MMP-II-specific memory T cells were more efficiently produced in mice inoculated with BCG-SM than in mice inoculated with BCG-pMV. Taken together, these results indicate that BCG capable of secreting the immunodominant Ag is more potent in the stimulation of T cells.
Random Mutagenesis of Helicobacter pylori vacA To Identify Amino Acids Essential for Vacuolating Cytotoxic Activity
Authors: McClain Mark S. , Czajkowsky Daniel M. , Torres Victor J. , Szabo Gabor , Shao Zhifeng , Cover Timothy L. 
Published: October 2006

ABSTRACT

VacA is a secreted toxin that plays a role in
Helicobacter pylori
colonization of the stomach and may contribute to the pathogenesis of peptic ulcer disease and gastric cancer. In this study, we analyzed a library of plasmids expressing randomly mutated forms of recombinant VacA and identified 10 mutant VacA proteins that lacked vacuolating cytotoxic activity when added to HeLa cells. The mutations included six single amino acid substitutions within an amino-terminal hydrophobic region and four substitutions outside the amino-terminal hydrophobic region. All 10 mutations mapped within the p33 domain of VacA. By introducing mutations into the
H. pylori
chromosomal
vacA
gene, we showed that secreted mutant toxins containing V21L, S25L, G121R, or S246L mutations bound to cells and were internalized but had defects in vacuolating activity. In planar lipid bilayer and membrane depolarization assays, VacA proteins containing V21L and S25L mutations were defective in formation of anion-selective membrane channels, whereas proteins containing G121R or S246L mutations retained channel-forming capacity. These are the first point mutations outside the amino-terminal hydrophobic region that are known to abrogate vacuolating toxin activity. In addition, these are the first examples of mutant VacA proteins that have defects in vacuolating activity despite exhibiting channel activities similar to those of wild-type VacA.
Costs and compensation of work-related injuries in British Columbia sawmills
Authors: Alamgir Hasanat , Tompa Emile , Koehoorn Mieke , Ostry Aleck , Demers Paul A 
Published: October 2006

Objective:To estimate the costs of work-related injury in a cohort of sawmill workers in British Columbia from the perspective of the workers’ compensation system.Methods:Hospital discharge records were extracted from 1989 to 1998 for a cohort of 5786 actively employed sawmill workers. A total of 173 work-related injury cases were identified from these records using theInternational classification of diseases—ninth revision (ICD-9) external cause of injury codes and the responsibility of payment schedule. Workers’ compensation records were extracted and matched with hospital records by dates and ICD-9 diagnosis codes. All costs were converted into 1995 constant Canadian dollars using the Provincial General Consumer Price Index for the non-healthcare costs and Medical Consumer Price Index for the healthcare costs. A 5% discounting rate was applied to adjust for the time value of money. For the uncompensated cases, costs were imputed from the compensated cases using the median cost for a similar nature of injury.Results:370 hospitalisation events due to injury were captured, and by either of the two indicators (E Codes or payment schedules), 173 (47%) hospitalisation events due to injury, were identified as work related. The median healthcare cost was $4377 and the median non-healthcare cost was $16 559 for a work-related injury. The median non-healthcare and healthcare costs by injury were falls, $19 978 and $5185; struck by falling object, $32 398 and $8625; struck against, $12 667 and $5741; machinery related, $26 480 and $6643; caught in or between, $24 130 and $4389; and overexertion, $7801 and $2710. The total cost was $10 374 115 for non-healthcare and $1 764 137 for healthcare. The compensation agency did not compensate $874 871 (8.4%) of the non-healthcare costs and $200 588 (11.4%) of the healthcare costs.Conclusion:Eliminating avoidable work-related injury events can save valuable resources.
Spreading of occupational allergens: laboratory animal allergens on hair-covering caps and in mattress dust of laboratory animal workers
Authors: Krop Esmeralda J M , Doekes Gert , Stone Martin J , Aalberse Rob C , van der Zee Jaring S 
Published: October 2006

Background:Family members of laboratory animal workers are at risk of developing allergy to laboratory animals. Little is known about the spreading of laboratory animal allergens outside the animal facilities.Objective:To assess the presence of laboratory animal allergens in dust collected from mattresses of laboratory animal workers and unexposed controls.Methods:Mouse and rat urinary proteins were measured in samples of mattress dust collected by laboratory animal workers and unexposed controls. In addition, rat and mouse allergens were determined in extracts of hair-covering caps, used during laboratory animal work, to estimate spreading of allergen through dust captured on hair. Allergen concentrations on hair caps were compared with exposure measured by personal airborne dust sampling.Results:Levels of rat urinary allergens (RUA) and mouse urinary allergens (MUA) and mouse urinary protein (MUP) 8, a specific pheromone-binding mouse allergen, were significantly higher in mattress samples of laboratory animal workers than in those of controls. Hair-covering caps used in animal facilities harboured large amounts of RUA and MUA, which correlated significantly with exposure measured by the personal sampling technique in the animal facility.Conclusions:Occupational laboratory animal allergens are detectable in mattress dust of laboratory animal workers. Transfer of allergens via uncovered hair of animal workers is likely contributing to this phenomenon. This study stresses the importance of using hair caps to prevent spreading of occupational allergens.
The paralogous hematopoietic regulators Lyl1 and Scl are coregulated by Ets and GATA factors, but Lyl1 cannot rescue the early Scl–/– phenotype
Authors: Chan Wan Y. I. , Follows George A. , Lacaud Georges , Pimanda John E. , Landry Josette-Renee , Kinston Sarah , Knezevic Kathy , Piltz Sandie , Donaldson Ian J. , Gambardella Laure , Sablitzky Fred , Green Anthony R. , Kouskoff Valerie , Göttgens Berthold 
Published: October 2006

AbstractTranscription factors are key regulators of hematopoietic stem cells (HSCs), yet the molecular mechanisms that control their expression are largely unknown. Previously, we demonstrated that expression of Scl/Tal1, a transcription factor required for the specification of HSCs, is controlled by Ets and GATA factors. Here we characterize the molecular mechanisms controlling expression of Lyl1, a paralog of Scl also required for HSC function. Two closely spaced promoters directed expression to hematopoietic progenitor, megakaryocytic, and endothelial cells in transgenic mice. Conserved binding sites required for promoter activity were bound in vivo by GATA-2 and the Ets factors Fli1, Elf1, Erg, and PU.1. However, despite coregulation of Scl and Lyl1 by the same Ets and GATA factors, Scl expression was initiated prior to Lyl1 in embryonic stem (ES) cell differentiation assays. Moreover, ectopic expression of Scl but not Lyl1 rescued hematopoietic differentiation in Scl−/− ES cells, thus providing a molecular explanation for the vastly different phenotypes of Scl−/− and Lyl1−/− mouse embryos. Furthermore, coregulation of Scl and Lyl1 later during development may explain the mild phenotype of Scl−/− adult HSCs.
Fluorescence in situhybridization (FISH) analysis of primary ocular adnexal MALT lymphoma
Authors: Tanimoto Kazuki , Sekiguchi Naohiro , Yokota Yukiko , Kaneko Akihiro , Watanabe Takashi , Maeshima Akiko Miyagi , Matsuno Yoshihiro , Harada Mine , Tobinai Kensei , Kobayashi Yukio 
Published: October 2006

Abstract

Background
It remains unknown whether primary ocular adnexal extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a homogeneous entity, as there are few reports of the results of cytogenetic or molecular analyses of these tumors.

Methods
We performed interphase fluorescence in situ hybridization (FISH) analysis to detect translocations and aneuploidy in 34 cases of primary ocular adnexal MALT lymphoma, and reviewed the histopathological findings. Correlations between the results of FISH analysis, the histopathological features and the clinical data were also analyzed.

Results
Among the 34 cases, FISH analysis revealed t(14;18)(q32;q21) in one case, trisomy 3 in 21 cases (62%), and trisomy 18 in 16 cases (47%). The cases with trisomy 18 had significantly more prominent lymphoepithelial lesions (LELs) and less nodularity in the tumors. In regard to the clinical correlations, tumors with trisomy 18 were observed predominantly in females and younger patients; also, in the majority of the cases, the tumor was of conjunctival origin. All the cases with recurrence showed trisomy 18 in the tumor.

Conclusion
Primary ocular adnexal MALT lymphoma is a significantly heterogeneous entity. Cases with trisomy 18 may have unique clinicopathological features.
Human immunodeficiency virus infection and macrophage cholesterol metabolism
Authors: Bukrinsky Michael , Sviridov Dmitri 
Published: October 2006

Abstract
Macrophages play a central role in the pathogenesis of atherosclerosis and are also a host for a number of viruses, most importantly, HIV. Many viruses, including HIV, require cholesterol for their replication and as a structural element. Cholesterol also plays a pivotal role in innate antiviral immune responses. Although impairing innate immune response by increasing cell cholesterol content may be a deliberate strategy used by a pathogen to improve its infectivity, enhancing the risk of atherosclerosis is likely a byproduct. Consistent association between HIV infection and elevated risk of atherosclerosis suggested a connection between virus-induced changes in cholesterol metabolism and atherogenesis, but the mechanisms of such connection have not been identified. We describe in this review various mechanisms enabling viruses to exploit macrophage pathways of cholesterol metabolism, thus diverting cholesterol for a purpose of increasing viral replication and/or for altering innate immune responses. To alter the cellular cholesterol content, viruses “hijack” the pathways responsible for maintaining intracellular cholesterol metabolism. The damage to these pathways by viral infection may result in the inability of macrophages to control cholesterol accumulation and may lead to formation of foam cells, a characteristic feature of atherosclerosis. Further elucidation of the mechanisms connecting viral infection and macrophage cholesterol metabolism may be fruitful for developing approaches to treatment of atherosclerosis and viral diseases.
A Gray Zone Assigned to Inconclusive Results of Quantitative Diagnostic Tests: Application to the Use of Brain Natriuretic Peptide for Diagnosis of Heart Failure in Acute Dyspneic Patients
Authors: Coste Joël , Jourdain Patrick , Pouchot Jacques 
Published: October 2006

AbstractBackground: Most quantitative diagnostic tests do not perfectly differentiate between persons with and without a given disease. We present a simple method to construct a 3-zone partition for quantitative tests results, including positive and negative zones and a gray zone between, and we describe its use in the diagnosis of heart failure by brain natriuretic peptide (BNP) measurement in acute dyspneic patients.Methods: We conducted a prospective cohort study of 699 consecutive patients with acute dyspnea who were treated at the emergency department of 3 participating hospitals. Heart failure (acute or decompensated) was assessed independently at discharge by cardiologists blind to the results of BNP measurements.Results: The discriminatory performance of BNP was insufficient to provide a single cutoff value that could be used to correctly diagnose heart failure in clinical practice. Also, the discriminatory performance differed between patients with and without a history of chronic heart failure. The gray zone of inconclusive results was 167–472 ng/L for those without and 0–334 ng/L for those with such a history. Diagnosis of the current episode of heart failure by BNP results and history of heart failure was not enhanced by data from any other sources, including electrocardiography.Conclusions: The gray zone approach applied to the diagnosis of heart failure by BNP might allow sensible cutoff values to be determined for clinical practice according to relevant subgroups of patients. The gray zone approach might be usefully applied to many other quantitative tests and clinical diagnostic or screening problems.
Investigation into the Effects of Materials and Mixing Procedures on Air Void Characteristics of Fresh Concrete Using Air Void Analyzer (AVA)
Authors: Zhang S , Wang K 
Published: October 2006

Abstract
The air void analyzer (AVA) was used to investigate the effects of concrete materials and mixing procedures on air void characteristics of fresh concrete. Twenty-seven batches of concrete were made with three mix proportions (with and without Class C fly ash or water reducer), and they were mixed with five mixing procedures (one-step mixing for 1, 2, or 4 min, two-step mixing for 4 min and ASTM C 192 lab mixing procedures) and two sizes of pan mixers (0.014 and 0.042 m3 or 0.5 and 1.5 ft3). The air content, size distribution, specific surface, and spacing factor of all the batch mixtures were examined. The results indicated that incorporating 15 % Class C fly ash replacement or recommended dosage of a lignin-based water reducer into concrete generally reduced the spacing factor of air voids. The two-step mixing method (mixing mortar for 2 min first, and then mixing the mortar with coarse aggregate for another 2 min) produced a lower air void spacing factor than the one-step, 4-min mixing method (mixing all concrete materials together at once). For concrete mixed with the one-step mixing method, the air void spacing factor reduced with mixing time. For a given concrete mixture and mixing procedure, use of different sizes of mixers provided the mixtures with different air content and different spacing factor. The air void characteristics of the corresponding fresh and hardened concrete were also examined using the Type B pressure meter and RapidAir test methods, respectively. The correlations between the results from AVA, Type B pressure meter, and RapidAir tests were studied.
Efficient Induction of Oligodendrocytes from Human Embryonic Stem Cells
Authors: Kang Sang-Moon , Cho Myung Soo , Seo Hyemyung , Yoon Chul Jong , Oh Sun Kyung , Choi Young Min , Kim Dong-Wook 
Published: October 2006

Abstract
Oligodendrocytes form myelin sheaths around axons to support rapid nerve conduction in the central nervous system (CNS). Damage to myelin can cause severe CNS disorders. In this study, we attempted to devise a protocol for the induction of oligodendrocytes from human embryonic stem (ES) cells to treat demyelinated axons. Four days after embryoid body formation, human ES cells were differentiated into neural precursors through selection and expansion procedures. Neural precursors were then grown in the presence of epidermal growth factor and then platelet-derived growth factor to generate oligodendrocyte precursor cells. After withdrawal of the growth factors, the cells were treated with thyroid hormone to induce differentiation into oligodendrocytes. This method resulted in ∼81%–91% oligodendrocyte precursor cells and ∼81% oligodendrocytes among total cells. The ability of the oligodendrocyte precursors to myelinate axons has been verified by coculturing with rat hippocampal neurons, confirming their biological functionality.