bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clonal Relatedness of EnterotoxigenicEscherichia coliStrains Isolated from a Cohort of Young Children in Guinea-Bissau
Authors: Steinsland Hans , Valentiner-Branth Palle , Aaby Peter , Mølbak Kåre , Sommerfelt Halvor 
Published: July 2004

ABSTRACTIn a cohort study of 200 young children in Guinea-Bissau, it was previously found that some enterotoxigenicEscherichia coli(ETEC) strains were more pathogenic than others, depending on the type of toxin that they could produce, and that natural ETEC infections induced substantial protection against new infections with ETEC strains that had the same combination of toxins and colonization factors (CFs). We wanted to describe the clonal relatedness of the ETEC strains isolated during this study and to investigate whether the protective antigens and the virulence factors that were responsible for the pathogenic traits were common to strains that were clonally closely related or whether they were more likely to be encoded by the ETEC virulence plasmids that normally encode the toxins and the CFs. By performing repetitive sequence-based PCR analysis of strains representing 452 infections, we found that strains that had the same toxin-CF profile were usually closely related, although a few were unrelated. Strains that did not have the same toxin-CF profiles but that were positive for a given toxin or for a given CF were not consistently more closely related to each other than to strains that were negative for the same toxin or CF. Our results indicate that the pathogenic traits of ETEC were mainly attributed to genes carried on the ETEC virulence plasmids. Because most strains that had the same toxin-CF profile were closely related, it seems likely that the toxin-CF-specific protection was clonal and was not targeting antigens encoded by the virulence plasmids. These results are of relevance to the ETEC vaccine development effort.
Diversity among Community Isolates of Methicillin-Resistant
Staphylococcus aureus
in Australia
Authors: O'Brien F. G. , Lim T. T. , Chong F. N. , Coombs G. W. , Enright M. C. , Robinson D. A. , Monk A. , Saïd-Salim B. , Kreiswirth B. N. , Grubb W. B. 
Published: July 2004

ABSTRACT

Community methicillin-resistant
Staphylococcus aureus
(CMRSA) strains are being isolated with increasing frequency around the world. In Western Australia CMRSA are endemic in geographically remote communities and have been found to belong to five different contour-clamped homogeneous electric field (CHEF) electrophoretic patterns. Representatives of each of these CHEF patterns have been compared to CMRSA representative of CHEF patterns from other Australian states and New Zealand. With one exception, all of the isolates were nonmultiresistant and were not resistant to many antimicrobial agents other than the β-lactams. With one exception, which is not believed to be a CMRSA, all of the isolates harbored a β-lactamase plasmid. Erythromycin resistance was associated with a 2-kb plasmid. One of the β-lactamase plasmids was found to be able to acquire additional resistance determinants to become a multiple resistance plasmid. There were 10 multilocus sequence types belonging to eight distantly related clonal complexes of
S. aureus
. One new sequence type was found. Although most of the CMRSA harbored the type IVa SCC
mec
, a type IV structural variant was found and two new SCC
mec
types were identified. Protein A gene (
spa
) typing revealed two new
spa
types and, with two exceptions, corresponded to multilocus sequence typing. In contrast to other reports on CMRSA, most of the CMRSA strains studied here did not contain the Panton-Valentine leukocidin genes. The results also demonstrate that nonmultiresistant hospital strains such as UK EMRSA-15 may be able to circulate in the community and could be mistaken for CMRSA based on their resistance profiles.
LightCycler-Based Differentiation of
Mycobacterium abscessus
and
Mycobacterium chelonae
Authors: Sedlacek L. , Rifai M. , Feldmann K. , Bange F. C. 
Published: July 2004

ABSTRACT

In this study we introduce a rapid procedure to identify
Mycobacterium abscessus
(types I and II) and
M. chelonae
using LightCycler-based analysis of the
hsp65
gene. Results from 36 clinical strains were compared with
hsp65
gene restriction analysis and biochemical profiles of bacilli. As all three methods yielded identical results for each isolate, this procedure offers an excellent alternative to previously established nucleic acid amplification-based techniques for the diagnosis of mycobacterial diseases.
Influenza B Virus Victoria Group with a New Glycosylation Site Was Epidemic in Japan in the 2002-2003 Season
Authors: Nakagawa Naoko , Kubota Ritsuko , Maeda Akiko , Okuno Yoshinobu 
Published: July 2004

ABSTRACT
In the 2002-2003 season, influenza B virus Victoria strains were epidemic after a 6-year absence in Kobe City, Japan. They reacted poorly to the immune ferret sera prepared for use against the previous strain. An amino acid substitution in the HA1 region caused them to acquire an N-linked glycosylation site.
Cloning and Characterization of
Trichophyton rubrum
Genes Encoding Actin, Tri r2, and Tri r4
Authors: Gao Jimin , Takashima Akira 
Published: July 2004

ABSTRACT

The three structural genes of
Trichophyton rubrum
encoding actin (3,429 bp) and two antigens, Tri r2 (2,950 bp) and Tri r4 (3,988 bp), were cloned and characterized. They contained six, four, and five exons, respectively. The
T. rubrum
actin protein sequence revealed extremely high homology to other fungal actins.
Serotypes and Genotypes of Erythromycin-Resistant Group B Streptococci in Korea
Authors: Uh Young , Jang In Ho , Hwang Gyu Yel , Lee Mi Kyung , Yoon Kap Jun , Kim Hyo Youl 
Published: July 2004

ABSTRACT

Among 78 erythromycin-resistant group B streptococcus (GBS) isolates from Korea,
ermB
was detected in 58 (74.4%),
mefA
was detected in 14 (17.9%), and
ermTR
was detected in 6 (7.7%). The most prevalent serotypes of erythromycin-resistant GBS were V (detected in 34 isolates [43.6%]) and III (detected in 33 isolates [42.3%]). All serotype V erythromycin-resistant GBS harbored the
ermB
gene.
Application of Oxidation-Reduction Assay for Monitoring Treatment of Patients with Pulmonary Tuberculosis
Authors: Farnia Parissa , Mohammadi Foroazan , Mirsaedi Mehdi , Zarife Abolhasan Zia , Tabatabee Javad , Bahadori Katayoon , Bahadori Muslem , Masjedi Mohammad Reza , Velayati Ali Akbar 
Published: July 2004

ABSTRACT

By oxidation-reduction assay, the viability of
Mycobacterium tuberculosis
in sputum specimens was evaluated. The technique is based on the Alamar Blue and Malachite Green dyes, which change their color in response to
M. tuberculosis
growth. The method is simple, permits visual reading of results, and is applicable for laboratories with limited resources.
Differences in Clinical Manifestation of
Streptococcus pneumoniae
Infection Are Not Correlated with In Vitro Production and Release of the Virulence Factors Pneumolysin and Lipoteichoic and Teichoic Acids
Authors: Spreer Annette , Lis Astrid , Gerber Joachim , Reinert Ralf René , Eiffert Helmut , Nau Roland 
Published: July 2004

ABSTRACT
Production and release of the pneumococcal virulence factors pneumolysin and lipoteichoic and teichoic acid in 75 clinical isolates were investigated. No difference was found between strains causing systemic infection or localized respiratory infection and isolates from asymptomatic carriers. This suggests that the presence of pneumolysin and lipoteichoic and teichoic acid is a necessary but not a sufficient condition for pneumococcal infection and development of invasive disease.
Extended-Spectrum-β-Lactamase (TEM-52)-Producing Strains of
Salmonella enterica
of Various Serotypes Isolated in France
Authors: Weill François-Xavier , Demartin Marie , Fabre Laëtitia , Grimont Patrick A. D. 
Published: July 2004

ABSTRACT

From 2002 to 2003, four isolates of
Salmonella enterica
serotypes Typhimurium, Enteritidis, Blockley, and Panama, isolated in France from patients with gastroenteritis, were found to produce extended-spectrum β-lactamase TEM-52. The study showed the
bla
TEM-52
gene to be located in a Tn
3
-like structure and carried by 100- or 32-kb conjugative plasmids.
Bacteriology of a Bear Bite Wound to a Human: Case Report
Authors: Kunimoto Dennis , Rennie Robert , Citron Diane M. , Goldstein Ellie J. C. 
Published: July 2004

ABSTRACT

Human contact with bears has become more frequent, as has the resultant bear maulings and bite injuries. We report the bacteriology of a patient bitten by a grizzly bear (
Ursus arctos
) from the Rocky Mountains foothills area east of Banff National Park, Alberta, Canada. The patient received field care, including metronidazole and cefazolin. Subsequent deep-wound cultures grew
Serratia fonticola
,
Serratia marcescens
,
Aeromonas hydrophila
,
Bacillus cereus
, and
Enterococcus durans
but no anaerobes.
Grinding Characteristics of Carbon Fiber Epoxy Composite Hollow Shafts
Authors: Kim Po Jin , Lee Dai Gil , Choi Jin Kyung 
Published: July 2004

Since carbon fiber epoxy composite materials have excellent structural properties due to their high specific strength, high modulus, high damping and low thermal expansion, composite hollow shafts have been widely used for power transmission shafts for motor vehicles, spindles for machine tools, and rollers for thin film processing. However, the surfaces of molded composite shafts are not always satisfactory for precise mechanical elements, which often requires turning or grinding of surfaces. The machining characteristics of composite hollow shafts are different from those of conventional metal hollow shafts because composite hollow shafts have anisotropic inhomogeneous material characteristics. In this paper, the grinding characteristics of composite hollow flexible shafts were investigated experimentally and analytically with respect to stacking sequence and stiffness of carbon fiber epoxy hollow composite shafts.
Viscoelastic Properties of Multiphase Polymeric Blends
Authors: Pieroni Paula , Ercoli Daniel , Goizueta Graciela , Capiati Numa 
Published: July 2004

Rheological analysis of multi-phase systems is very difficult because the morphology is strongly related to the flow history. The small amplitude oscillatory shear flow does not affect the morphology and is very useful to predict the viscoelastic behavior of immiscible blends. In this work we study the dynamic rheological properties of polypropylene based ternary blends with linear low density polyethylene and ethylene/propylene terpolymers of different viscosities taking into account the effects of changing the composition and concentration of the dispersed phase. The predictions of a constitutive equation for emulsions of viscoelastic fluids are also included.
Discrete-Wavelet Analysis of Acoustic Emissions During Fatigue Loading of Carbon Fiber Reinforced Composites
Authors: Kamala Girish , Hashemi Javad , Barhorst Alan A. 
Published: July 2004

Wavelet transform decomposition was used to gather time-frequency-based information from acoustic emission signals generated during fatigue loading of unidirectional Carbon Fiber Reinforced Composite (FRC). The acoustic emissions were detected using a resonant sensor and were digitized for analysis. The sensor response was de-convolved from the acquired signal using a point-by-point divisional spectral method. The analysis of the collected signals revealed that friction-related emissions due to the fretting of fractured surfaces are of very high frequency and can mask emissions due to actual damage. Through utilization of wavelet transforms, it became possible to present the spectral composition of a transient signal (AK signal) in a time-frequency map which is not easily achieved through conventional spectral analysis techniques. It was determined that most of the acoustic energy (95%) was localized in levels corresponding to central frequencies of 120, 250, and 310 kHz. Results indicate friction-related emissions are associated with levels 8 and 9 and have a frequency range of 250-300 kHz. There are indications that matrix related emissions are of high frequency and high acoustic energy. The results indicate that wavelet analysis would be an effective tool in the analysis of AE by providing information relative to the frequency of the emissions.
Acoustic Attenuation for Ultrasonic NDI Detection of Delaminations on Composite Laminates
Authors: Briotti G. , Scarponi C. 
Published: July 2004

The purpose of the paper is to show the importance of the acoustic attenuation and probe frequency for the reliable evaluation of delaminations on composite materials subjected to NDI ultrasonic investigation. An original ultrasonic NDI methodology has been applied to some composite materials of wide application, characterized by a high acoustic attenuation. The materials are based on Kevlar/polyester and glass/polyester systems; the fiber form is woven fabric, and the thicknesses are between 5 and 6 mm. All the specimens are made by RTM technology. The specimens have been subjected to low-velocity impact tests, and then the extension of delaminated areas has been evaluated. The ultrasonic test apparatus operates in the form of reflection, using two different probes at 5 and 15 MHz. The results point out how the higher frequency probe has a greater resolution and higher sensibility; nevertheless, the higher attenuation at 15 MHz causes a lower inspection depth along the specimen thickness. Thus, for materials with high attenuation the 5 MHz probe is preferable in order to have accurate ultrasonic maps along the thickness and reliable values for the delaminated areas.
Elastic-Plastic Stress Analysis of Metal Matrix Laminated Plates Under In-Plane and Transverse Loading
Authors: Sayman O. , Özbay M. , Akbulut H. 
Published: July 2004

Metal matrix composites reinforced by fibers give high strengths, specific stiffness, ductility, yield point and a good temperature performance. They provide a relatively new way of strengthening metals. In recent years several low cost manufacturing techniques have been developed. In this study, continuous stainless steel reinforced aluminum matrix composite manufactured by die casting process has been used as a simply supported symmetric and antisymmetric laminated plate loaded by in-plane and transverse forces. An elastic-plastic numerical solution has been carried out by finite element technique for several iteration numbers. Residual stresses and the expansion of the plastic zone have been illustrated in tables and figures.
Urokinase-deficient and urokinase receptor-deficient mice have impaired neutrophil antimicrobial activation in vitro
Authors: Gyetko Margaret R , Aizenberg David , Mayo-Bond Laura 
Published: July 2004

AbstractLeukocytes express both urokinase-type plasminogen activator (uPA) and the urokinase receptor (uPAR, CD87). We have shown that neutrophil recruitment to the lung during P. aeruginosa pneumonia is impaired in uPAR-deficient (uPAR−/−) mice but is normal in uPA−/− mice. However, both uPA−/− mice and uPAR−/− mice have impaired lung clearance of P. aeruginosa compared with wild-type (WT) mice. To determine the role of uPA and uPAR in antibacterial host defense, we compared neutrophil bacterial-phagocytosis, respiratory burst, and degranulation among uPA−/−, uPAR−/−, and WT mice. Nutrophil phagocytosis was significantly diminished comparing uPA−/− and uPAR−/− mice with WT mice at all time points. The generation of superoxide by both uPA−/− and uPAR−/− neutrophils was about half of that seen in WT neutrophils. Degranulation of azurophilic granules was significantly diminished in uPA−/− neutrophils compared with either uPAR−/− or WT neutrophils. By contrast, agonist-stimulated release of specific granules was not diminished in either uPA−/− or uPAR−/− mice compared with WT. We conclude that the uPA/uPAR system modulates several of the crucial steps in neutrophil activation that result in bacterial killing and effective innate host defense.
Changes to peptide structure, not concentration, contribute to expansion of the lowest avidity cytotoxic T lymphocytes
Authors: Leggatt Graham R , Narayan Sharmal , Fernando Germain J P , Frazer Ian H 
Published: July 2004

AbstractThe efficient in vitro expansion of antigen-specific CD8+ cytotoxic T lymphocytes (CTL) for use in adoptive immunotherapy represents an important clinical goal. Furthermore, the avidity of expanded CTL populations often correlates closely with clinical outcome. In our study, high-avidity CTL lines could be expanded ex vivo from an antigen-primed animal using low peptide concentration, and intermediate peptide concentrations favored the generation of lower avidity CTL. Further increases in peptide concentration during culture inhibited the expansion of all peptide-specific CD8+ cells. In contrast, a single amino acid variant peptide efficiently generated functional CTL populations at high or low peptide concentration, which responded to wild-type epitope with the lowest average avidity seen in this study. We propose that for some peptides, the efficient generation of low-avidity CTL responses will be favored by stimulation with altered peptide rather than high concentrations of wild-type epitope. In addition, some variant peptides designed to have improved binding to major histocompatibility complex class I may reduce rather than enhance the functional avidity for the wild-type peptide of ex vivo-expanded CTL. These observations are relevant to in vitro expansion of CTL for immunotherapy and strategies to elicit regulatory or therapeutic immunity to neo-self-antigen when central tolerance has eliminated high-avidity, cognate T cells.
Involvement of multiple P2Y receptors and signaling pathways in the action of adenine nucleotides diphosphates on human monocyte-derived dendritic cells
Authors: Marteau Frédéric , Communi Didier , Boeynaems Jean-Marie , Suarez Gonzalez Nathalie 
Published: July 2004

AbstractAdenosine 5′-triphosphate (ATP), which is released from necrotic cells, induces a semimaturation state of dendritic cells (DC), characterized by the up-regulation of costimulatory molecules and the inhibition of proinflammatory cytokines. This action is mediated by cyclic adenosine monophosphate (cAMP) and involves the P2Y11 receptor. As DC express the ecto-enzyme CD39, which converts ATP into adenosine 5′-diphosphate (ADP), the effects of adenine nucleotides diphosphates on molecular signaling [intracellular calcium ([Ca2+]i), cAMP, extracellular signal-regulated kinase 1 (ERK1)], costimulatory molecule expression (CD83), and cytokine production [interleukin (IL)-12, tumor necrosis factor α (TNF-α), IL-10] were investigated in human monocyte-derived DC. ADP, 2-methylthio-ADP, and ADPβS had no effect on cAMP, increased [Ca2+]i, and stimulated the phosphorylation of ERK1. The effect on ERK1 was inhibited by AR-C69931MX, a P2Y12 and P2Y13 antagonist. On the contrary the effect on [Ca2+]i was neither inhibited by AR-C69931MX or by the P2Y1 antagonist MRS-2179. Both effects were inhibited by pertussis toxin. ADPβS alone was less potent for up-regulation of CD83 than ATPγS and did not increase the CD83 expression by DC stimulated with lipopolysaccharide (LPS). Similar to ATPγS, ADPβS inhibited the release of IL-12p40, IL-12p70, and TNF-α stimulated by LPS (1–100 ng/ml). The inhibitory effect of ADPβS on IL-12 release was neither reversed by AR-C69931MX or by MRS-2179. The two nucleotides had opposite effects on IL-10 production: inhibition by ADPβS and potentiation by ATPγS. In conclusion, ATP can modulate the function of DC, directly via a cAMP increase mediated by the P2Y11 receptor and indirectly via its degradation into ADP, which acts via Gi-coupled receptors coupled to ERK activation and calcium mobilization. These distinct mechanisms converge on the inhibition of inflammatory cytokine production, particularly IL-12, but have a differential effect on IL-10.
Heme oxygenase 1 expression induced by IL-10 requires STAT-3 and phosphoinositol-3 kinase and is inhibited by lipopolysaccharide
Authors: Ricchetti Giuseppe A , Williams Lynn M , Foxwell Brian M J 
Published: July 2004

AbstractHeme-oxygenase 1 (HO-1) is a stress-response protein with anti-inflammatory activity. This study has examined the regulation of HO-1 expression by the anti-inflammatory factor, interleukin (IL)-10 and whether HO-1 could account for the function of the cytokine. IL-10-induced expression of HO-1 required the activation of signal transducer and activator of transcription (STAT)-3 but not p38 mitogen-activated protein kinase. However, expression of HO-1 also required the activation of the phosphatidylinositol-3 kinase pathway, a signaling mechanism not required for the anti-inflammatory activity of IL-10. Moreover, induction of HO-1 expression was not restricted to IL-10, as IL-6, a cytokine known to activate STAT-3, could also induce the protein. In human macrophages, lipopolysaccharide inhibited HO-1 expression induced by IL-10 Also, inhibition of HO-1 activity by the specific inhibitor zinc-II-protoporphyrin-IX had no effect on the anti-inflammatory function of IL-10. In summary, although IL-10 does regulate HO-1 expression, it does not appear to play a significant role in the anti-inflammatory activity of the cytokine.
Structure and regulation of the neutrophil respiratory burst oxidase: comparison with nonphagocyte oxidases
Authors: Quinn Mark T , Gauss Katherine A 
Published: July 2004

AbstractNeutrophils play an essential role in the body's innate defense against pathogens and are one of the primary mediators of the inflammatory response. To defend the host, neutrophils use a wide range of microbicidal products, such as oxidants, microbicidal peptides, and lytic enzymes. The generation of microbicidal oxidants by neutrophils results from the activation of a multiprotein enzyme complex known as the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which is responsible for transferring electrons from NADPH to O2, resulting in the formation of superoxide anion. During oxidase activation, cytosolic oxidase proteins translocate to the phagosome or plasma membrane, where they assemble around a central membrane-bound component known as flavocytochrome b. This process is highly regulated, involving phosphorylation, translocation, and multiple conformational changes. Originally, it was thought that the NADPH oxidase was restricted to phagocytes and used solely in host defense. However, recent studies indicate that similar NADPH oxidase systems are present in a wide variety of nonphagocytic cells. Although the nature of these nonphagocyte NADPH oxidases is still being defined, it is clear that they are functionally distinct from the phagocyte oxidases. It should be noted, however, that structural features of many nonphagocyte oxidase proteins do seem to be similar to those of their phagocyte counterparts. In this review, key structural and functional features of the neutrophil NADPH oxidase and its protein components are described, including a consideration of transcriptional and post-translational regulatory features. Furthermore, relevant details about structural and functional features of various nonphagocyte oxidase proteins will be included for comparison.