bluuebunny/crossref_metadata_2025_split huggingface dataset:
Outcome of Vancomycin Treatment in Patients with Methicillin-SusceptibleStaphylococcus aureusBacteremia
Authors: Kim Sung-Han , Kim Kye-Hyung , Kim Hong-Bin , Kim Nam-Joong , Kim Eui-Chong , Oh Myoung-don , Choe Kang-Won 
Published: November 2007

ABSTRACTLimited data on the clinical outcome of vancomycin treatment compared with that of beta-lactam treatment in patients with methicillin-susceptibleStaphylococcus aureusbacteremia (MSSA-B) are available. We used different and complementary approaches: (i) a retrospective cohort study using a propensity score to adjust for confounding by treatment assignment and (ii) a matched case-control study. Of all patients withS. aureusbacteremia (SAB) in two university-affiliated hospitals over a 7-year period, 294 patients with MSSA-B were enrolled in the cohort study. The cases for the case-control study were defined as patients who received vancomycin treatment for MSSA-B; the controls, who were patients that received beta-lactam treatment for MSSA-B, were selected at a 1:2 (case:control) ratio according to the objective matching scoring system and the propensity score system. In the cohort study, SAB-related mortality in patients with vancomycin treatment (37%, 10/27) was significantly higher than that in those with beta-lactam treatment (18%, 47/267) (P= 0.02). In addition, multivariate analysis revealed that vancomycin treatment was associated with SAB-related mortality when independent predictors for SAB-related mortality and propensity score were considered (adjusted odds ratio of 3.3, 95% confidence interval of 1.2 to 9.5). In the case-control study using the objective matching scoring system and the propensity score system, SAB-related mortality in case patients was 37% (10/27) and in control patients 11% (6/54) (P< 0.01). Our data suggest that vancomycin is inferior to beta-lactam in the treatment of MSSA-B.
Modulation of Intestinal Goblet Cell Function during Infection by an Attaching and Effacing Bacterial Pathogen
Authors: Bergstrom Kirk S. B. , Guttman Julian A. , Rumi Mohammad , Ma Caixia , Bouzari Saied , Khan Mohammed A. , Gibson Deanna L. , Vogl A. Wayne , Vallance Bruce A. 
Published: November 2007

ABSTRACT

The attaching and effacing (A/E) bacterial pathogens enteropathogenic
Escherichia coli
and enterohemorrhagic
E. coli
and the related mouse pathogen
Citrobacter rodentium
colonize their hosts' intestines by infecting the apical surfaces of enterocytes, subverting their function, and they ultimately cause diarrhea. Surprisingly, little is known about the interactions of these organisms with goblet cells, which are specialized epithelial cells that secrete the protective molecules Muc2 and trefoil factor 3 (Tff3) into the intestinal lumen.
C. rodentium
infection leads to dramatic goblet cell depletion within the infected colon, yet it is not clear whether
C. rodentium
infects goblet cells or if this pathology is pathogen or host mediated. As determined by immunostaining and PCR, both the number of goblet cells and the expression of genes encoding Muc2 and Tff3 were significantly reduced by day 10 postinfection. While electron microscopy and immunostaining revealed that
C. rodentium
directly infected a fraction of colonic goblet cells,
C. rodentium
localization did not correlate with goblet cell depletion. To assess the role of the host immune system in these changes, Rag1 knockout (KO) (T- and B-cell-deficient) mice were infected with
C. rodentium
. Rag1 KO mice did not exhibit the reduction in the number of goblet cells or in mediator (Muc2 and Tff3) expression observed in infected immunocompetent mice. However, reconstitution of Rag1 KO mice with T and B lymphocytes from C57BL/6 mice restored the goblet cell depletion phenotype during
C. rodentium
infection. In conclusion, these studies demonstrated that while colonic goblet cells can be subject to direct infection and potential subversion by A/E pathogens in vivo, it is the host immune system that primarily modulates the function of these cells during infection.
Brucella abortusInhibits Major Histocompatibility Complex Class II Expression and Antigen Processing through Interleukin-6 Secretion via Toll-Like Receptor 2
Authors: Barrionuevo Paula , Cassataro Juliana , Delpino M. Victoria , Zwerdling Astrid , Pasquevich Karina A. , Samartino Clara García , Wallach Jorge C. , Fossati Carlos A. , Giambartolomei Guillermo H. 
Published: November 2007

ABSTRACTThe strategies that allowBrucella abortusto survive inside macrophages for prolonged periods and to avoid the immunological surveillance of major histocompatibility complex class II (MHC-II)-restricted gamma interferon (IFN-γ)-producing CD4+T lymphocytes are poorly understood. We report here that infection of THP-1 cells withB. abortusinhibited expression of MHC-II molecules and antigen (Ag) processing. Heat-killedB. abortus(HKBA) also induced both these phenomena, indicating the independence of bacterial viability and involvement of a structural component of the bacterium. Accordingly, outer membrane protein 19 (Omp19), a prototypicalB. abortuslipoprotein, inhibited both MHC-II expression and Ag processing to the same extent as HKBA. Moreover, a synthetic lipohexapeptide that mimics the structure of the protein lipid moiety also inhibited MHC-II expression, indicating that anyBrucellalipoprotein could down-modulate MHC-II expression and Ag processing. Inhibition of MHC-II expression and Ag processing by either HKBA or lipidated Omp19 (L-Omp19) depended on Toll-like receptor 2 and was mediated by interleukin-6. HKBA or L-Omp19 also inhibited MHC-II expression and Ag processing of human monocytes. In addition, exposure to the synthetic lipohexapeptide inhibited Ag-specific T-cell proliferation and IFN-γ production of peripheral blood mononuclear cells fromBrucella-infected patients. Together, these results indicate that there is a mechanism by whichB. abortusmay prevent recognition by T cells to evade host immunity and establish a chronic infection.
Association between foot type and tibial stress injuries: a systematic review
Authors: Barnes A , Wheat J , Milner C 
Published: November 2007

Objectives:To systematically review published articles investigating the association between structural foot characteristics and tibial stress injuries, and to suggest possible future avenues of research in this area.Methods:Literature was identified, selected and appraised in accordance with the methods of a systematic review. Articles potentially relevant to the research question were identified by searching the following electronic databases: Amed, Cinahl, Index to UK theses, Medline, PubMed, Scopus, Sports discus and Web of science. Duplicates were removed and, based on the title and abstract, the full text of relevant studies were retrieved. Two reviewers independently assessed papers; this formed the basis for the inclusion of the most appropriate trials.Results:From the 479 articles originally identified, nine were deemed appropriate for inclusion in the review. In general, specific data relating to this relationship was limited. Outcomes of the nine investigations were difficult to compare due to differing methods used across studies. Results have proved conflicting, with limited evidence found to implicate any specific foot type as a potential risk factor for tibial stress injuries.Conclusions:No definitive conclusions can be drawn relating foot structure or function to an increased risk of tibial stress injuries. Extremes of foot types are likely to pose an increased risk of tibial stress injuries compared to normal arched feet.
Effects of fungal seed pathogens under conspecific and heterospecific trees in a temperate forest
Authors: Kotanen Peter M. 
Published: November 2007

This study investigated the impacts of soil fungi on seeds of two eastern North American temperate-zone trees: Acer saccharum Marsh. (sugar maple) and Tsuga canadensis (L.) Carr (eastern hemlock). Seeds of each species were buried at locations dominated by either conspecifics or heterospecifics. Half were protected with fungicide, and the net consequences for survival and germination were assessed. Net effects of fungicide usually were positive, indicating that pathogens affected seeds more strongly than any potential mutualists. Losses of A. saccharum to fungi were modest, and almost identical in areas dominated by itself versus areas dominated by T. canadensis. In contrast, fungal impacts on T. canadensis were strongly habitat-dependent: losses to fungi were high in T. canadensis-dominated sites, but not in A. saccharum-dominated sites. This result is consistent with an accumulation of host-specific pathogens, either by a direct feedback between T. canadensis and its fungal enemies, or indirectly through modification of the soil environment. Even though these two trees share similar habitats, responses to fungicide indicate that their seeds are affected very differently by the soil environment.
Ultrastructure of teliospores and promycelium and basidiospore formation in the two-spored form of Gymnoconia nitens, one of the causes of orange rust of Rubus
Authors: Mims Charles W. , Richardson Elizabeth A. 
Published: November 2007

Gymnoconia nitens (Schwein.) Kern & H. W. Thurston consists of two forms that cause orange rust of Rubus . The teliospores of both of these forms are morphologically identical to aeciospores, but upon germination form promycelia that give rise to either two or four basidiospores. In this study, we examined the teliospores and the sequence of events leading to basidiospore development in the two-spored form of G. nitens. The teliospores of this species are formed in chains from uninucleate sporogenous cells that line the base of each sorus on infected Rubus argutus Link. (blackberry) leaves. Fluorescence microscopy revealed that approximately 90% of the mature teliospores were uninucleate. During germination, the teliospore nucleus migrated into the developing promycelium and underwent a single mitotic division. A transverse septum formed between the two daughter nuclei creating two uninucleate cells. A tapered sterigma arose from each cell and gave rise to a basidiospore. These findings indicate that the basidiospores of the two-spored form of G. nitens were formed in an asexual fashion.
Insights into the faulting process from numerical simulations of rock-layer bending
Authors: Couples G. D. , Lewis H. , Olden P. , Workman G. H. , Higgs N. G. 
Published: November 2007

Abstract

An elastic–plastic material model, with strain-hardening or -softening, and volumetric strains, implemented within a general-purpose finite-element system (SAVFEM
TM
), is shown to reproduce the stress–strain relationships and localized to de-localized (brittle to ductile) changes in strain response that have long been observed in typical laboratory experiments on common porous rocks. Based on that validation of the implementation, SAVFEM
TM
is then used to create numerical simulations that reproduce the patterns of localized shear zones, and their growth history, that occur in experimental (physical) models of fold–fault systems in layered rocks. These simulations involve a progressive evolution of the mechanical state, illustrating a geometrically dominated type of localization behaviour. Part of the deformation simulated here represents a crestal graben system. Analysis of the evolving mechanical state in the system of simulated faults poses challenges to some longstanding ideas concerning the way that faults operate, suggesting the need for a new fault-process paradigm.
Improved seismic identification of inter-fault damage via a linked geomechanics-seismic approach
Authors: Hall S. A. , Lewis H. , Macle X. 
Published: November 2007

Abstract
Predicting deformation-driven permeability changes in the subsurface requires knowledge of the character and distribution of dilatant and compactant rock damage. Seismic reflection data can be used to gain insight into aspects of the deformation such as the geometry of seismically resolvable faults and bulk material property distributions. However, interpretations of material properties from seismic data are non-unique. This paper addresses the use of established seismic techniques to identify the signatures of fault-associated open fractures, modified and improved by a new linked geomechanics–seismic approach. The paper also addresses how each of stress state and open fractures affect seismic anisotropy. The geomechanics–seismic approach is demonstrated using a model of a North Sea hydrocarbon field in which a series of potential fracture arrays are assumed and the fracture apertures are modified to reflect the geomechanically generated stress states. Seismic anisotropy predictions based on these modified fracture distributions are then compared with a pre-existing seismic anisotropy interpretation to determine the best match. Using geomechanical simulation to support a seismic anisotropy-based method produces a higher-confidence result and can lead to better prediction of altered permeabilities in faulted regions. Because of the geomechanical focus of this Special Publication, the background for seismic identification of faults and inter-fault damage is also outlined, including a review of current seismic practice.
Localization processes in a coupled hydrogeomechanically sensitive fractured system
Authors: Reynolds M. A. , Couples G. D. , Lewis H. , Pickup G. E. 
Published: November 2007

Abstract
Simulation of coupled dynamic fluid flow and geomechanical loading of fractured systems shows that complex behaviours can result, even for geometrically simple fracture systems and simple loading. Using a bi-directionally coupled simulation tool, HYDRO–DDA, we examine how fluids and discontinuum processes interact in a fractured, porous rock layer that is being flexed. The changes in fracture aperture, and hence the equivalent permeabilities of this system, exhibit marked localization or delocalization responses in spite of the geometrical and mechanical simplicity of this model. Typically the linked flow-deformation behaviour develops markedly non-linear responses. In some cases the permeability varies by more than three orders of magnitude for minor changes in input variables. Upscaling methods that are suitable representations of this permeability variation are developed. These non-linear behaviours develop in a porous material, which would be expected to suppress non-linear effects. If the range of behaviours seen in this geometrically simple coupled system is typical of other, potentially more complex, fully coupled systems, then the results obtained here can be used to explain the spatially and temporally high variability of the permeability characteristics of fractured systems.
The progression from damage to localization of displacement observed in laboratory testing of porous rocks
Authors: Logan J. M. 
Published: November 2007

Abstract

Laboratory experiments suggest that fault zones form in porous rocks through the extension and coalescence of fractures of predictable geometries. These fractures form in an array of Riedel fractures in R
1
, R
2
, P and Y orientations. Displacement along closely spaced fractures leads to the formation of comminuted fault gouge. Localization of displacement within the fault gouge progresses from distributed shearing to comminution and compaction of the fault rock material culminating in fractures in the Riedel orientations. Colour boundaries within the simulated gouge zones show the change in accommodation of displacement to fractures in the Y orientation as shear strain progresses. Clay–quartz mixtures demonstrate that the clay inhibits localization and the achievement of steady-state sliding as well as stick-slip. A reduction in the coefficient of friction does not occur until about 30% of the clay is present and continues to decrease until about 70% is reached. Localization of slip appears as a necessary condition for steady-state sliding as well as unstable behaviour. Field studies show the implication of grain-size reduction in the localization process by porosity decrease inhibiting fluid flow normal to the fault zone. The pervasive Y fractures, however, facilitate fluid migration parallel to some faults.
Microscale damage evolution in compacting sandstone
Authors: DiGiovanni A. A. , Fredrich J. T. , Holcomb D. J. , Olsson W. A. 
Published: November 2007

Abstract
Recent field, laboratory, and theoretical studies suggest that under certain stress conditions, compaction of porous rock may be accommodated by narrow zones of localized compressive deformation oriented perpendicular to the maximum compressive stress. Triaxial compression experiments were performed on Castlegate sandstone, an analogue reservoir sandstone, that included acoustic emission detection and location. Initially, acoustic emissions were concentrated in horizontal bands that initiated at the sample ends (perpendicular to the maximum compressive stress) but, with continued loading, progressed axially towards the sample centre. High-resolution field-emission SEM was performed to elucidate the micromechanics of compaction. The microscopy revealed that compaction of this weakly cemented sandstone proceeded in two phases: an initial stage of porosity decrease accomplished by breakage of grain contacts and grain rotation, and a second stage of further porosity reduction accommodated by intense grain breakage and rotation. Quantitative stereological measurements corroborated the decrease in the intergrain spacing and the increase in grain boundary contacts that the microstructural observations suggest occurred during the first stage of compaction. The microstructural data show that a five-fold increase in the surface area per unit volume resulted from the extensive microfracturing that occurred during the second stage of compaction.
Influence of grain size and geothermal gradient on the ductile-to-brittle transition in arenaceous sedimentary rocks: implications for fault structure and fluid flow
Authors: Fisher Q. J. , Harris S. D. , Casey M. , Knipe R. J. 
Published: November 2007

Abstract
To investigate the interaction between the rheology of arenaceous sedimentary rocks (sand and sandstone) and stress conditions during burial we have coupled published results from deformation experiments with a simple quartz cementation model. The model provides valuable insights into controls on sandstone deformation consistent with observations from nature. A transitional zone exists in subsiding sedimentary basins, here referred to as the ductile-to-brittle transition (DBT), above which faults in normally pressured arenites will tend to form fluid flow barriers, and below which they will tend to form conduits. The DBT depth in sandstone is dependent upon geothermal gradient, burial rate and grain size. Low geothermal gradients, rapid sedimentation rates and coarse grain sizes favour a deep DBT and vice versa. Fine-grained arenites may only deform in a brittle manner for most natural burial rates and geothermal gradients, explaining why they do not usually contain thick deformation band zones. Coarser-grained arenites may deform in a brittle–ductile or ductile manner, which is why they often contain thick deformation band zones and occasionally experience pervasive porosity collapse. Sandstones within high geothermal gradient areas may deform to produce fluid flow conduits at shallow depths when porosities in the sequence as a whole are high; this possibly favours fault-related mineralization.
Fracture aperture, length and pattern geometry development under biaxial loading: a numerical study with applications to natural, cross-jointed systems
Authors: Olson J. E. 
Published: November 2007

Abstract
Fracture mechanics modelling of fracture pattern development was used to analyse pattern geometry and population statistics for natural opening-mode fractures. Orthogonal fracture network geometries were generated under biaxial extension loading conditions from a slightly anisotropic initial strain state. Fracture statistics were analysed by grouping all fracture orientations into one population for these unique orthogonal pattern geometries. Fracture aperture distributions resembled negative exponential curve shapes, consistent with published observations for stratabound fractures in sedimentary rock. Fracture length distributions had a strongly power-law shape, and showed that longer fractures grew first and reached their fullest extent before shorter fractures began propagating. The power-law shape of the length distribution was first established by the growth of the longest fractures in the population, followed by the later growth of shorter fractures that extended the power-law shape to smaller sizes. The shortest fracture length at which the power-law distribution was truncated varied with the magnitude of the applied strain. Other variations in fracture pattern results were tied to mechanical layer thickness and subcritical crack growth propagation properties of the fractured media.
Permeability of fault rocks from the Median Tectonic Line in Ohshika-mura, Nagano, Japan as studied by pressure-cycling tests
Authors: Uehara S. , Shimamoto T. 
Published: November 2007

Abstract

We describe laboratory measurements of the permeability of fault rocks and their host protoliths obtained from the Median Tectonic Line (MTL), the largest strike-slip fault in Japan. The measurements are made using a gas-medium apparatus that simulates
in situ
conditions. Samples of fault gouge, cataclastic mylonite, and protoliths were collected from the Kitagawa and Ankoh outcrops of the MTL and adjacent areas in Ohshika-mura, Nagano Prefecture, central Japan. Permeabilities of these samples were measured at room temperature under dry conditions, with nitrogen as the pore fluid. Most samples from the incohesive fault zone have a permeability ranging between 10
−13
and 10
−17
m
2
(100–0.01 mD). These permeabilities are greater than those of cemented cataclasites and mylonites by more than two orders of magnitude at all effective pressures (
P
e
) up to 180 MPa. Clayey fault gouge material has a permeability as low as 10
−19
m
2
(0.1 µD) at high effective pressures, but such impermeable fault gouge does not constitute a continuous zone on the two outcrops we studied. Permeability of the incohesive fault rocks exhibits large hysteresis upon
P
e
cycling, compared with cataclasite and mylonite, because those cemented, cohesive fault rocks undergo much less inelastic deformation during the pressure cycling.
‘Dowel’ pinning for feline metacarpal and metatarsal fractures
Authors: Kornmayer M. , Matis U. , Zahn K. 
Published: November 2007

SummaryThe goal of this retrospective study was to describe dowel pinning, and to compare the results of osteosynthesis and external coaptation of metacarpal and metatarsal fractures in cats. Evaluation of the medical records of 351 cats yielded 63 cats treated with dowel pinning, 35 cats treated with external coaptation and 14 cats treated with both methods within the same limb. All of the cats had been re-evaluated at an average of 2.8 years (six months – 15 years) postoperatively. Dowel pinning was superior to external coaptation when all fractured bones of a limb could be pinned. When internal fixation of multiple fractures was not feasible in all fractured bones due to comminution or fragments that were too short to pin, the outcome was not significantly different from cases treated with external coaptation alone. Malunion was seen in 16% of fractured bones in cats treated with external coaptation and occurred secondary to implant bending in 3% of fractured bones treated with dowel pinning. The latter refers to one operated cat, which had four metacarpal fractures in the same limb. Radiographs taken at re-evaluation showed implant migration within the medullary canal in two cats, although neither showed any signs of non-union or lameness. Non-union was seen in one operated cat, in which the fracture (MC IV) could not be completely reduced with a K-wire. Osteomyelitis did not occur. Dowel pinning is an easy, inexpensive and effective technique for repair of metacarpal and metatarsal fractures in cats.