bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Right, Left, and Biventricular Pacing on Myocardial Perfusion in Ischemic Conditions
Authors: LAFITTE STEPHANE , REANT PATRICIA , LABROUSSE LOUIS , BORDACHAR PIERRE , TARIOSSE LILIANE , BEAUVOIT BERTRAND , SERRI KARIM , BONORON‐ADÈLE SIMONE , ROUDAUT RAYMOND , SANTOS PIERRE DOS 
Published: August 2006

Objectives: In normal hearts, the distribution of regional myocardial perfusion is altered by ventricular pacing. Little is known about the impact of ventricular pacing on regional myocardial perfusion in ischemic conditions. In this acute echocardiographic study, we compared the respective effects of right ventricular pacing (RVP), left ventricular pacing (LVP), and biventricular pacing (BVP) on regional perfusion in a swine model of graded ischemia. Methods and Results: Ventricular pacing leads were placed at the apex of the right ventricle and on the lateral wall of the left ventricle in nine open‐chest pigs. Myocardial contrast echocardiography was successively performed during spontaneous rhythm (SR), RVP, LVP, and BVP in random order at baseline and during three stages of incremental ischemia (left anterior descending + circumflex). At baseline, RVP decreased myocardial perfusion of the septal and inferior walls compared to SR (P < 0.05), whereas LVP decreased perfusion of the lateral wall (P < 0.05). No significant differences were observed in regional perfusion during BVP compared to SR. In ischemic conditions, RVP worsened myocardial perfusion in the ischemic anterior wall as well as in the septal and inferior walls (P < 0.05), whereas both LVP and BVP did not alter perfusion in the ischemic area compared to SR. Conclusion: Compared to baseline, in ischemic conditions, RVP has a more pronounced detrimental impact on perfusion abnormalities. In contrast, BVP induced a significant improvement in local myocardial perfusion. Therefore, BVP could be preferred to RVP in patients with ischemic cardiomyopathy.
Post‐Operative Atrial Fibrillation Is Influenced by Beta‐Blocker Therapy But Not by Pre‐Operative Atrial Cellular Electrophysiology
Authors: WORKMAN ANTONY J. , PAU DAVIDE , REDPATH CALUM J. , MARSHALL GILLIAN E. , RUSSELL JULIE A. , KANE KATHLEEN A. , NORRIE JOHN , RANKIN ANDREW C. 
Published: August 2006

Introduction: We investigated whether post‐cardiac surgery (CS) new‐onset atrial fibrillation (AF) is predicted by pre‐CS atrial cellular electrophysiology, and whether the antiarrhythmic effect of beta‐blocker therapy may involve pre‐CS pharmacological remodeling. Methods and Results: Atrial myocytes were obtained from consenting patients in sinus rhythm, just prior to CS. Action potentials and ion currents were recorded using whole‐cell patch‐clamp technique. Post‐CS AF occurred in 53 of 212 patients (25%). Those with post‐CS AF were older than those without (67 ± 2 vs 62 ± 1 years, P = 0.005). In cells from patients with post‐CS AF, the action potential duration at 50% and 90% repolarization, maximum upstroke velocity, and effective refractory period (ERP) were 13 ± 4 ms, 217 ± 16 ms, 185 ± 10 V/s, and 216 ± 14 ms, respectively (n = 30 cells, 11 patients). Peak L‐type Ca2+ current, transient outward and inward rectifier K+ currents, and the sustained outward current were −5.0 ± 0.5, 12.9 ± 2.4, −4.1 ± 0.4, and 9.7 ± 1.0 pA/pF, respectively (13–62 cells, 7–19 patients). None of these values were significantly different in cells from patients without post‐CS AF (P > 0.05 for each, 60–279 cells, 29–86 patients), confirmed by multiple and logistic regression. In patients treated >7 days with a beta‐blocker pre‐CS, the incidence of post‐CS AF was lower than in non‐beta‐blocked patients (13% vs 27%, P = 0.038). Pre‐CS beta‐blockade was associated with a prolonged pre‐CS atrial cellular ERP (P = 0.001), by a similar degree (∼20%) in those with and without post‐CS AF. Conclusion: Pre‐CS human atrial cellular electrophysiology does not predict post‐CS AF. Chronic beta‐blocker therapy is associated with a reduced incidence of post‐CS AF, unrelated to a pre‐CS ERP‐prolonging effect of this treatment.
Lifetime Cumulative Incidence of Syncope in the General Population: A Study of 549 Dutch Subjects Aged 35–60 Years
Authors: GANZEBOOM KARIN S. , MAIRUHU GIDEON , REITSMA JOHANNES B. , LINZER MARK , WIELING WOUTER , VAN DIJK NYNKE 
Published: August 2006

Introduction:There are limited and conflicting data on the lifetime cumulative incidence of syncope in the general population. The aim of our study was to determine the lifetime cumulative incidence and triggers of syncope in the general population.Methods:Questions about syncope were added to a cross‐sectional survey on cardiovascular risk factors carried out between 2001 and 2003 in 549 native Dutch respondents, aged 35–60 years.Results:The lifetime cumulative incidence of syncope in our study population was 35% (95% confidence interval 31–39%). Syncope occurred more often in women than in men (41% vs 28%; P = 0.003). A peak in the incidence of syncope occurred around the age of 15 years in both men and women. The median number of episodes in persons with syncope was 2 (Inter Quartile Range 1–5). The top five most frequently mentioned triggers of syncope included warm environment, pain, insufficient food intake, seeing blood/venipuncture, and emotion.Conclusion:In conclusion, our study shows that the lifetime cumulative incidence of syncope in the general population is high. Females experience syncope more often than males. The majority of the syncope triggers were related to conditions that affect orthostatic blood pressure regulation and vasomotor responses.
TiO2‐Doped Zirconia: Crystal Structure, Monoclinic‐Tetragonal Phase Transition, and the New Tetragonal Compound Zr3TiO8
Authors: Troitzsch Ulrike 
Published: August 2006

Zirconia samples with up to 27 mol% TiO2were synthesized at low and elevated pressures, significantly extending the range of ZrO2–TiO2solid solution compared with previous crystal structure studies of monoclinic and tetragonal zirconia (<17.5 mol%). Crystal structure data collected by powder X‐ray diffraction (XRD) at ambient conditions reveal that the solid solution of TiO2in monoclinic zirconia (baddeleyite structure,P21/c) is limited to about 25 mol%, where the tetragonal compound Zr3TiO8forms. Changes in the monoclinic crystal structure with increasing TiO2can be understood in the light of the nearing monoclinic–tetragonal phase change. Unit‐cell dimensionsaandbbecome near identical, cell angle β starts to drop toward 90°, and atom positions start to change toward those of the tetragonal cell. The cation coordination polyhedron in the monoclinic structure becomes increasingly distorted, and bond–valence sums worsen. The transition from the monoclinic to the tetragonal lattice with increasing TiO2is not smooth however, but shows a significant jump in many of the parameters, in line with the first‐order character of this transition.The previously unknown inorganic compound Zr3TiO8has a structure related to that of tetragonal zirconia (P42/nmc), whereby weak superstructure reflections indicate that the structure is ordered and has a doubledc‐dimension. Zr3TiO8has the unit‐cell dimensionsa=5.0317(4) Å andc=10.4273(7) Å, space group (I‐42m), and is isostructural with the compound Zr3GeO8, with Ti4+in tetrahedral coordination and Zr4+in eightfold coordination. The stabilization of tetragonal Zr3TiO8at ambient conditions depends strongly on the cooling rate, which has to be slow enough (e.g., 1°C/min) to allow for ordering to occur. Rapid quenching (e.g., ∼140°C/s) of the same composition results in monoclinic zirconia. The lowering of the tetragonal–monoclinic phase transition to ambient conditions near 25 mol% TiO2is in good agreement with extrapolations from previous studies. The relatively coarse grain size (<20 μm) of the Zr3TiO8crystals suggest that the tetragonal structure was not retained because of grain‐size effects, but was stabilized predominantly by crystal structure adjustments based on cation size. Broadening and shortening of selected XRD peaks especially upon grinding suggests that tetragonal Zr3TiO8, depending on cooling rate and degree of ordering, may be retained metastably at room temperature, and is thus a potential candidate for TZP ceramics.
The criterion validity of the Geriatric Depression Scale: a systematic review
Authors: Wancata J. , Alexandrowicz R. , Marquart B. , Weiss M. , Friedrich F. 
Published: August 2006

Objective:  The objective was to provide a systematic review of the screening accuracy of both versions of the Geriatric Depressions Scale (GDS‐30, GDS‐15).Method:  An electronic search was performed by using Medline, Embase, Cinahl, Psyndex and the Cochrane library. The selection and examination of papers were performed by two reviewers independently.Results:  Among the 42 papers included, important methodological aspects such as sampling methods or blinding of research workers often were not reported. For both GDS versions, similar validity indices were found (GDS‐30: sensitivity 0.753, specificity 0.770; GDS‐15: sensitivity 0.805, specificity 0.750). Using comparative studies based on the identical samples, both GDS versions showed significantly better validity indices than the ‘Yale‐1‐question’ screen, but were similar to the ‘Center for Epidemiological Studies Depression scale’ (CES‐D).Conclusion:  The GDS does not show a better criterion validity than the CES‐D, but methodological limitations of primary studies hamper the generalizability of pooled analyses.
Antidepressants and sexual dysfunction
Authors: Werneke U. , Northey S. , Bhugra D. 
Published: August 2006

Objective: Many patients with depression suffer from sexual dysfunction and sexual dysfunction is a recognized side‐effect of antidepressants. The aim of this review was to examine the prevalence of psychosexual dysfunction associated with antidepressants, and to review treatment options which are specific to the affected component of sexual functioning and antidepressants.Method: Comprehensive literature review using Medline and Cochrane databases.Results: Up to 70% of patients with depression may have sexual dysfunction. Tricyclic antidepressants, selective‐serotonin reuptake inhibitors and venlafaxine are most and the non‐serotonergic antidepressants and duloxetine least likely to produce sexual dysfunction. Pharmacological treatment options include antidepressants less likely associated or ‘antidotes’ to reverse sexual dysfunction.Conclusion: Sexual dysfunction may be a preventable or treatable side‐effect of antidepressants. Patients need routinely to be asked about sexual function to identify problems early. If sexual dysfunction is ignored it may maintain the depression, compromise treatment outcome and lead to non‐compliance.
Cross-correlation of Wilkinson Microwave Anisotropy Probe third-year data and the Sloan Digital Sky Survey DR4 galaxy survey: new evidence for dark energy
Authors: Cabré A. , Gaztañaga E. , Manera M. , Fosalba P. , Castander F. 
Published: August 2006

Abstract
We cross-correlate the third-year Wilkinson Microwave Anisotropy Probe (WMAP) data with galaxy samples extracted from the SDSS DR4 (SDSS4) covering 13 per cent of the sky, increasing the volume sampled in previous analysis by a factor of 3.7. The new measurements confirm a positive cross-correlation with higher significance (total signal-to-noise ratio of about 4.7). The correlation as a function of angular scale is well fitted by the integrated Sachs–Wolfe (ISW) effect for Λ cold dark matter (ΛCDM) flat Friedmann–Robertson–Walker models with a cosmological constant. The combined analysis of different samples gives ΩΛ = 0.80–0.85 (68 per cent confidence level, CL) or 0.77–0.86 (95 per cent CL). We find similar best-fitting values for ΩΛ for different galaxy samples with median redshifts of z≃ 0.3 and z≃ 0.5, indicating that the data scale with redshift as predicted by the LCDM cosmology (with equation of state parameter w =−1). This agreement is not trivial, but cannot yet be used to break the degeneracy constraints in the w versus ΩΛ plane using only the ISW data.
Actinobacillus actinomycetemcomitansOuter Membrane Protein 100 Triggers Innate Immunity and Production of β-Defensin and the 18-Kilodalton Cationic Antimicrobial Protein through the Fibronectin-Integrin Pathway in Human Gingival Epithelial Cells
Authors: Ouhara Kazuhisa , Komatsuzawa Hitoshi , Shiba Hideki , Uchida Yushi , Kawai Toshihisa , Sayama Koji , Hashimoto Koji , Taubman Martin A. , Kurihara Hidemi , Sugai Motoyuki 
Published: August 2006

ABSTRACTAntimicrobial peptides, human β-defensin (hBD), and the 18-kDa cationic antimicrobial protein (CAP18) are components of innate immunity. These peptides have antimicrobial activity against bacteria, fungi, and viruses.Actinobacillus actinomycetemcomitansis a gram-negative facultative anaerobe implicated in the initiation of periodontitis. The innate immunity peptides have antibacterial activity againstA. actinomycetemcomitans. We investigated the molecular mechanism of human gingival epithelial cells (HGEC) responding to exposure toA. actinomycetemcomitans. HGEC constitutively express hBD1 and inducibly express hBD2, hBD3, and CAP18 on exposure toA. actinomycetemcomitans. The level of expression varies among clinical isolates. In the signaling pathway for hBD2 induction by the bacterial contact, we demonstrate that the mitogen-activated protein (MAP) kinase and not the NF-κB transcription factor pathway is used. We found the outer membrane protein 100 (Omp100; identified by molecular mass) is the component inducing the hBD2 response. Omp100 binds to fibronectin, an extracellular matrix inducing hBD2 via the MAP kinase pathway. Anti-integrin α5β1, antifibronectin, genistein, and PP2 suppress the Omp100-induced expression of hBD2, suggesting that Src kinase is involved through integrin α5β1. The inflammatory cytokines, tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-8, produced by HGEC on contact withA. actinomycetemcomitansalso stimulate expression of hBD2. Further, neutralizing antibody against TNF-α or IL-8 partially inhibits the induction of hBD2 on bacterial contact. Therefore, we found that the induction of the antimicrobial peptides is mediated by a direct response principally through an Omp100-fibronectin interaction, and using secondary stimulation by inflammatory cytokines induced by the bacterial exposure.
Porphyromonas gingivalis
Vesicles Enhance Attachment, and the Leucine-Rich Repeat BspA Protein Is Required for Invasion of Epithelial Cells by “
Tannerella forsythia
”
Authors: Inagaki Satoru , Onishi Shinsuke , Kuramitsu Howard K. , Sharma Ashu 
Published: August 2006

ABSTRACT

The human oral cavity harbors more than 500 species of bacteria. Periodontitis, a bacterially induced inflammatory disease that leads to tooth loss, is believed to result from infection by a select group of gram-negative periodontopathogens that includes
Porphyromonas gingivalis
,
Treponema denticola
, and “
Tannerella forsythia
” (opinion on name change from
Tannerella forsythensis
pending; formerly
Bacteroides forsythus
). Epithelial cell invasion by periodontopathogens is considered to be an important virulence mechanism for evasion of the host defense responses. Further, the epithelial cells with invading bacteria also serve as reservoirs important in recurrent infections. The present study was therefore undertaken to address the epithelial cell adherence and invasion properties of
T. forsythia
and the role of the cell surface-associated protein BspA in these processes. Further, we were interested in determining if
P. gingivalis
, one of the pathogens frequently found associated in disease, or its outer membrane vesicles (OMVs) could modulate the epithelial cell adherence and invasion abilities of
T. forsythia
. Here we show that epithelial cell attachment and invasion by
T. forsythia
are dependent on the BspA protein. In addition,
P. gingivalis
or its OMVs enhance the attachment and invasion of
T. forsythia
to epithelial cells. Thus, interactions between these two bacteria may play important roles in virulence by promoting host cell attachment and invasion.
ChronicSalmonella entericaSerovar Typhimurium-Induced Colitis and Cholangitis in Streptomycin-PretreatedNramp1+/+Mice
Authors: Stecher Bärbel , Paesold Günther , Barthel Manja , Kremer Marcus , Jantsch Jonathan , Stallmach Thomas , Heikenwalder Mathias , Hardt Wolf-Dietrich 
Published: August 2006

ABSTRACTSalmonella entericasubspecies 1 serovar Typhimurium is an enteric bacterial pathogen infecting a broad range of hosts. In susceptibleNramp1−/−(Slc11α1−/−) mice, serovar Typhimurium cannot efficiently colonize the intestine but causes a systemic typhoid-like infection. However, after pretreatment with streptomycin, these susceptible (C57BL/6 and BALB/c) mice develop acute serovar Typhimurium-induced colitis (M. Barthel et al., Infect. Immun.71:2839-2858, 2003). It was not clear whether resistantNramp1+/+(Slc11α1+/+) mouse strains would similarly develop colitis. Here we compared serovar Typhimurium infection in streptomycin-pretreated susceptible (C57BL/6) and resistant (DBA/2 and 129Sv/Ev) mouse strains: We found that acute colitis (days 1 and 3 postinfection) is strikingly similar in susceptible and resistant mice. In 129Sv/Ev mice we followed the serovar Typhimurium infection for as long as 6 weeks. After the initial phase of acute colitis, these animals developed chronic crypt-destructive colitis, including ulceration, crypt abscesses, pronounced mucosal and submucosal infiltrates, overshooting regeneration of the epithelium, and crypt branching. Moreover, we observed inflammation of the gall duct epithelium (cholangitis) in the 129Sv/Ev mice between days 14 and 43 of infection. Cholangitis was not attributable to side effects of the streptomycin treatment. Furthermore, chronic infection of 129Sv/Ev mice in a typhoid fever model did not lead to cholangitis. We propose that streptomycin-pretreated 129Sv/Ev mice provide a robust murine model for chronic enteric salmonellosis including complications such as cholangitis.
Role of the α-Helical Linker of the C-Terminal Translocator in the Biogenesis of the Serine Protease Subfamily of Autotransporters
Authors: Kostakioti Maria , Stathopoulos Christos 
Published: August 2006

ABSTRACTAutotransporters are secreted virulence factors that comprise three domains: an N-terminal signal peptide, an internal passenger domain, and a C-terminal β-domain. The mechanism of passenger translocation across the outer membrane remains undefined, with four models having been proposed: the “hairpin,” the “threading,” the “multimeric,” and the “Omp85 (YaeT)” models. In an attempt to understand autotransporter biogenesis, we screened the sequences of the serine protease subfamily of autotransporters (SPATEs) for conserved features indicative of a common secretion mechanism. Our analyses revealed a strictly conserved 14-amino-acid motif within the predicted α-helical linker region, upstream of the β-domain of SPATEs. We investigated the function of this motif through a mutagenesis approach using Tsh as a model. Our studies demonstrate that mutations throughout the conserved motif do not block insertion of the β-domain into the outer membrane. However, nonconservative mutations of four hydrophobic (V1099, L1102, G1107, and L1109) and three polar (N1100, K1104, and R1105) residues of the motif severely decrease or even abolish Tsh biogenesis. Further studies showed that these mutations interfere with passenger transport across the outer membrane. Bioinformatical analyses suggest that the critical polar and hydrophobic amino acids localize on opposite sides of the helix that runs through the β-barrel pore. Our data indicate that the conserved motif is important for passenger secretion across the outer membrane and that mutations in certain residues severely affect the secretion process. We discuss how these results fit with the four proposed models for autotransporter secretion and potential applications in antimicrobial and vaccine development.
Identification ofNeisseria meningitidisNonlipopolysaccharide Ligands for Class A Macrophage Scavenger Receptor by Using a Novel Assay
Authors: Peiser Leanne , Makepeace Katherine , Plüddemann Annette , Savino Silvana , Wright J. Claire , Pizza Mariagrazia , Rappuoli Rino , Moxon E. Richard , Gordon Siamon 
Published: August 2006

ABSTRACTMacrophages (Mφ) may play an important role in the pathogenesis of invasive meningococcal infection. Previously, we have shown that the class A Mφ scavenger receptor (SR-A) is a major nonopsonic receptor forNeisseria meningitidison Mφ. SR-A contributes to host defense by binding proinflammatory polyanionic ligands such as lipopolysaccharide (LPS) and by the uptake and killing of live organisms. SR-A-deficient mouse Mφ display a substantial reduction in the number of meningococci ingested compared to wild-type Mφ, and SR-A is required for meningococcal phagocytosis but not for the release of tumor necrosis factor alpha. Although soluble lipid A and lipidIVA are reported as ligands for SR-A, we demonstrated that LPS and LPS expression were not essential for the uptake of whole meningococci. In the present study, we set out to discover protein ligand(s) for SR-A inN. meningitidislysates and outer membrane vesicles. Using various microbial mutant strains, we determined that molecules comprising the membrane capsule and pili, as well as the abundant surface Opa proteins were not essential for SR-A recognition. We developed a binding assay to detect SR-A ligands and identified three candidate proteins expressed on intact organisms, namely, NMB1220, NMB0278, and NMB0667. Soluble forms of these ligands were shown to block the binding of meningococci to CHO cells stably transfected with SR-A. Furthermore, NMB1220 was endocytosed by SR-A on Mφ and prevented internalization of soluble acetylated low-density lipoprotein. Thus, we have identified novel, unmodified protein ligands for SR-A that are able to inhibit meningococcal interactions with macrophages in vitro.
Differential Regulation of Iron- and Manganese-Specific MtsABC and Heme-Specific HtsABC Transporters by the Metalloregulator MtsR of Group A
Streptococcus
Authors: Hanks Tracey S. , Liu Mengyao , McClure Michael J. , Fukumura Maki , Duffy Angela , Lei Benfang 
Published: August 2006

ABSTRACT

The genome of the human pathogen group A
Streptococcus
(GAS) encodes the transporters MtsABC, FtsABCD, and HtsABC to take up ferric and manganese ions, ferric ferrichrome, and heme, respectively. The GAS genome also encodes two metalloregulators PerR and MtsR. To understand the regulation of the expression of these transporters, the
mtsR
and
perR
deletion mutants of a GAS serotype M1 strain were generated, and the effects of the deletions and Fe
3+
, Mn
2+
, and Zn
2+
on the expression of
mtsA
,
htsA
, and
ftsB
were examined. Mn
2+
dramatically depresses
mtsA
transcription and levels of the MtsA protein but does not downregulate the expression of
htsA
and
ftsB
. Fe
3+
decreases the expression of
mtsA
and
htsA
but has no effect on
ftsB
expression. Zn
2+
has no effect on the expression of all three genes. The deletion of
mtsR
abolishes the Mn
2+
- and Fe
3+
-induced depression of
mtsA
expression and the Fe
3+
-dependent decrease in
htsA
expression. The deletion of
mtsR
does not significantly alter GAS virulence in a mouse model of subcutaneous infection. The deletion of
perR
does not affect the expression of the genes in response to the metal ions. MtsR binds to the
mts
promoter region in the presence of Mn
2+
or Fe
2+
. The results indicate that MtsR differentially regulates the expression of
mtsABC
and
htsABC
.