bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sterility of Dental Burs Directly from the Manufacturer
Authors: Hauptman Joel M. , Golberg Marvin B. , Rewkowski Carrie Ann
Published: September 2006

Background:  The purpose of this research was to assess the sterility of burs directly from manufacturers. The authors wished to determine the types of bacteria, if any, found on nonsterilized burs.

Methods:  The authors used burs from a major manufacturer. Sterilized and nonsterilized burs were cultured for bacteria. Any burs found to be contaminated were further cultured on agar plates. The bacteria on the plates were identified by a commercial laboratory.

Results:  Of the 100 sterilized and nonsterilized burs, the authors found none of the sterilized burs to be contaminated. Eight of the nonsterilized burs showed growth of bacteria after 24 hours. Seven of the eight bacteria identified on the burs belonged to the genus Bacillus.

Conclusions:  The Bacillus genus is encountered in daily living and is not considered to be pathogenic; however, there have been documented cases of infection in humans in which these bacteria dominate. They should never be introduced into the bloodstream.

CLINICAL SIGNIFICANCE

The dentist must consider that soft tissue exposure may be unavoidable with subgingival restorations or even those close to the gingiva. Therefore, it is imperative that the dentist use sterile burs during dental procedures. This article will prove the necessity for sterile burs and leave the rest to the manufacturers.
Analysis of protein interactions within the cytokinin‐signaling pathway of Arabidopsis thaliana
Authors: Dortay Hakan , Mehnert Nijuscha , Bürkle Lukas , Schmülling Thomas , Heyl Alexander
Published: September 2006

The signal of the plant hormone cytokinin is perceived by membrane‐located sensor histidine kinases and transduced by other members of the plant two‐component system. In Arabidopsis thaliana, 28 two‐component system proteins (phosphotransmitters and response regulators) act downstream of three receptors, transmitting the signal from the membrane to the nucleus and modulating the cellular response. Although the principal signaling mechanism has been elucidated, redundancy in the system has made it difficult to understand which of the many components interact to control the downstream biological processes. Here, we present a large‐scale interaction study comprising most members of the Arabidopsis cytokinin signaling pathway. Using the yeast two‐hybrid system, we detected 42 new interactions, of which more than 90% were confirmed by in vitro coaffinity purification. There are distinct patterns of interaction between protein families, but only a few interactions between proteins of the same family. An interaction map of this signaling pathway shows the Arabidopsis histidine phosphotransfer proteins as hubs, which interact with members from all other protein families, mostly in a redundant fashion. Domain‐mapping experiments revealed the interaction domains of the proteins of this pathway. Analyses of Arabidopsis histidine phosphotransfer protein 5 mutant proteins showed that the presence of the canonical phospho‐accepting histidine residue is not required for the interactions. Interaction of A‐type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B‐type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein‐mediated signaling. This study contributes to our understanding of the protein interactions of the cytokinin‐signaling system and provides a framework for further functional studies in planta.
Investigating Gata3 as a positional candidate gene for allergic asthma in a murine model
Authors: Li X. , Wills‐Karp M. , Ewart S.
Published: September 2006

Gata3 is a positional candidate gene for allergic asthma. We determined allergen‐induced GATA‐3 mRNA and protein expression in asthma susceptible and resistant mice and generated Gata3 sequence data. Our data indicate that the Gata3 gene in isolation is not a causative agent of asthma susceptibility in our model.
Th‐1 cytokines gene polymorphism in human brucellosis
Authors: Davoudi S. , Amirzargar A. A. , Hajiabdolbaghi M. , Rasoolinejad M. , Soodbakhsh A. , Jafari S. , Piri H. , Maleknejad P. , Bagherian H. , Madadi N. , Nikbin B.
Published: September 2006

Brucellosis is a worldwide zoonosis. Infection with Brucella species results in the activation of cell‐mediated immune response. The interaction between Th1and Th2 cytokines determines the outcome of disease. Production of each cytokine is in turn affected by genetic factors. In this study, we investigated the possible association between Th1 cytokines gene polymorphism and brucellosis. Different genotypes of TNF‐α, IFN‐γ and IL‐2 were determined by polymerase chain reaction–sequence‐specific primer in 47 patients with brucellosis and in 166 healthy controls. Allele frequencies of these genotypes were compared using the χ2 test. The results showed a significant difference in the TNF‐α genotype GG/GG in patients in comparison with controls (76.7% vs. 21%) (P = 0.001, OR = 12.42, 95%CI 5.7–27.7). There was no significant difference in the frequency distribution of the IFN‐γ genotypes between two groups. IL‐2 GG genotype at position −330 was about two times more common in cases than in controls, but the difference was not significant (10.6 vs. 4.6 P value = 0.09).This study shows that genetically low producers of TNF‐α are possibly susceptible to brucellosis and raise doubt about the role of gene polymorphism of INF‐γ in brucellosis which was demonstrated in previous studies. It seems that patients with brucellosis did not have a defect in producing IL‐2 with even a trend towards producing higher amounts of this cytokine.
SNPs in human β‐defensin 1 gene (DEFB1): frequencies in a Mexican population and new PCR–RFLPs assays
Authors: Prado‐Montes de Oca E. , Rangel‐Villalobos H. , Gallegos‐Arreola M. P. , Sandoval L. , Figuera L. E.
Published: September 2006

Polymerase chain reaction–restriction fragment length polymorphism assays for two single nucleotide polymorphisms in the human β‐defensin 1 gene have been validated with real‐time PCR in 101 healthy individuals from western Mexico. Allele frequencies were 52.5% (692‐A) and 98.5% (1836‐A). These assays can be confidently used as a cheaper alternative genotyping method for these sites.
Role of non‐HLA genetic polymorphisms in graft‐versus‐host disease after haematopoietic stem cell transplantation
Authors: Bertinetto F. E. , Dall’Omo A. M. , Mazzola G. A. , Rendine S. , Berrino M. , Bertola L. , Magistroni P. , Caropreso P. , Falda M. , Locatelli F. , Busca A. , Amoroso A.
Published: September 2006

Graft‐versus‐host disease (GvHD) is the main complication after haematopoietic stem cells transplantation (HSCT) and acute forms (aGvHD) occur in 20–40% of cases even after donor (D) and recipient (R) HLA matching, apparently because of D/R minor histocompatibility antigen (mHA) mismatches and cytokine polymorphisms. The genotype of cytokines and mHA of 77 haematological R following HSCT from HLA identical siblings were determined to detect genetic polymorphisms correlated with GvHD. We analysed TNFA (−863 C/A, −857 C/T and G/A at positions −574, −376, −308, −244, −238), IL‐10 (−1082 G/A, −819 C/A, −592 C/T), IL‐1B (T/C +3953), IL‐1RA (VNTR), HA‐1 (H/R allele) and CD‐31 (C/G at codon 125, A/G at codon 563). Allele frequencies were in Hardy–Weinberg equilibrium and similar to those of 77 healthy controls. We observed positive correlations between a lower risk of clinically significant aGvHD and both the presence of −1082G −819C −592C IL‐10 haplotype when both R and D are considered together and the absence of R IL‐1RA allele 2. Furthermore, we observed an association between the absence of TNF‐A −238 A allele and the risk of extensive chronic GvHD. mHA and cytokines genotyping would thus seem a valid source of information for the prior identification of recipients with a higher risk of aGvHD.
A NUMERICAL APPROACH WITH VARIABLE TEMPERATURE BOUNDARY CONDITIONS TO DETERMINE THE EFFECTIVE HEAT TRANSFER COEFFICIENT VALUES DURING BAKING OF COOKIES
Authors: DEMIRKOL EREN , ERDOGDU FERRUH , PALAZOGLU T. KORAY
Published: September 2006

The increasing trade of ready‐to‐eat foods such as cookies highlights an interest in quality defects during baking. Heat (h and thermal diffusivity) and mass (mass transfer and diffusion coefficients) transfer parameters are significant parameters affecting the quality changes. Therefore, it is important to determine these parameters for modeling and process optimization studies. Among these, the h is important, revealing the relationship between the heating medium and product surface. As baking involves a simultaneous heat and mass transfer involving moisture diffusion and heat conduction inside and convective heat and mass transfer outside, a lumped system method may not be an accurate choice to determine the h value. Changes in the product volume and contact heating from bottom of the product also bring extra challenges to the determination of h. Therefore, the objective of this study was to use realistic approaches including simultaneous heat and mass transfer to determine the changes in h. The heffvalues for the bottom and top surface of the cookies were then determined, applying a numerical procedure where the surface temperature changes were the boundary conditions with evaporation on the surface. The hband ht values increased with baking temperature and varied with baking time. The results of this study showed that evaporative mass flux for the top surface, heat flux for the bottom surface and the product's volume changes were significant in the variation of h values.
ASSESSMENT OF AN EXPONENTIAL MODEL FOR ULTRAFILTRATION OF APPLE JUICE
Authors: ÇETİNKAYA ÖZGE , GÖKMEN VURAL
Published: September 2006

The clarification of apple juice by ultrafiltration has been commercially used for many years. A common phenomenon in membrane processes is the decline of permeate flux (J) with time (t), called “membrane fouling.” The phenomenon of membrane fouling is very complex and difficult to describe theoretically, and model studies are limited. A number of semiempirical and empirical models have been proposed to explain flux behavior during membrane filtration processes. Using these models, typicaltversusJcurve observed in membrane filtration applications was examined in two or three periods. However, the boundaries between each period could not be accurately determined and were specific to the system under investigation. Thus, these semiempirical and empirical models are valid only for the system investigated. In this article, the applicability of an exponential model to ultrafiltration of apple juice was studied. The results showed that the exponential model can be successfully applied to analyze the raw filtrate volumeVversustdata of ultrafiltration of apple juice,and initial fluxJ0, membrane resistanceRmand exponential fouling coefficientkvalues can easily be determined from the raw data.
Thermomechanical Design of a Heat Exchanger for a Recuperative Aeroengine
Authors: Schoenenborn Harald , Ebert Ernst , Simon Burkhard , Storm Paul
Published: September 2006

Within the framework programs of the EU for Efficient and Environmentally Friendly Aero-Engines (EEFEA) MTU has developed a highly efficient cross-counter flow heat exchanger for the application in intercooled recuperated aeroengines. This very compact recuperator is based on the profile tube matrix arrangement invented by MTU and one of its outstanding features is the high resistance to thermal gradients. In this paper the combined thermomechanical design of the recuperator is presented. State-of-the-art calculation procedures for heat transfer and stress analysis are combined in order to perform a reliable life prediction of the recuperator. The thermal analysis is based upon a 3D parametric finite element model generation. A program has been generated, which allows the automatic generation of both the material mesh and the boundary conditions. Assumptions concerning the boundary conditions are presented as well as steady state and transient temperature results. The stress analysis is performed with a FEM code using essentially the same computational grid as the thermal analysis. With the static temperature fields the static loading of the profile tubes is determined. From transient thermal calculations successive 3D temperature fields are obtained which enable the determination of creep life and LCF life of the part. Finally, vibration analysis is performed in order to estimate the vibration stress of the profile tubes during engine operation. Together with the static stress a Goodman diagram can be constructed. The combined analysis shows the high life potential of the recuperator, which is important for economic operation of a recuperative aero-engine.
Subsurface Stress Fields in Face-Centered-Cubic Single-Crystal Anisotropic Contacts
Authors: Arakere Nagaraj K. , Knudsen Erik , Swanson Gregory R. , Duke Gregory , Ham-Battista Gilda
Published: September 2006

Single-crystal superalloy turbine blades used in high-pressure turbomachinery are subject to conditions of high temperature, triaxial steady and alternating stresses, fretting stresses in the blade attachment and damper contact locations, and exposure to high-pressure hydrogen. The blades are also subjected to extreme variations in temperature during start-up and shutdown transients. The most prevalent high-cycle fatigue (HCF) failure modes observed in these blades during operation include crystallographic crack initiation/propagation on octahedral planes and noncrystallographic initiation with crystallographic growth. Numerous cases of crack initiation and crack propagation at the blade leading edge tip, blade attachment regions, and damper contact locations have been documented. Understanding crack initiation/propagation under mixed-mode loading conditions is critical for establishing a systematic procedure for evaluating HCF life of single-crystal turbine blades. This paper presents analytical and numerical techniques for evaluating two- and three-dimensional (3D) subsurface stress fields in anisotropic contacts. The subsurface stress results are required for evaluating contact fatigue life at damper contacts and dovetail attachment regions in single-crystal nickel-base superalloy turbine blades. An analytical procedure is presented for evaluating the subsurface stresses in the elastic half-space, based on the adaptation of a stress function method outlined by Lekhnitskii (1963, Theory of Elasticity of an Anisotropic Elastic Body, Holden-Day, Inc., San Francisco, pp. 1–40). Numerical results are presented for cylindrical and spherical anisotropic contacts, using finite element analysis. Effects of crystal orientation on stress response and fatigue life are examined. Obtaining accurate subsurface stress results for anisotropic single-crystal contact problems require extremely refined 3D finite element grids, especially in the edge of contact region. Obtaining resolved shear stresses on the principal slip planes also involves considerable postprocessing work. For these reasons, it is very advantageous to develop analytical solution schemes for subsurface stresses, whenever possible.
Drag Coefficient and Stanton Number Behavior in Fluid Flow Across a Bundle of Wing-Shaped Tubes
Authors: Horvat Andrej , Mavko Borut
Published: September 2006

Transient numerical simulations of fluid and heat flow were performed for eight heat exchanger segments with cylindrical and wing-shaped tubes in staggered arrangement. Their hydraulic diameters dh were from 0.5824 to 3.899cm for the cylindrical tubes, and from 0.5413 to 3.594cm for the wing-shaped tubes. Based on the recorded time distributions of velocity uf(t) and temperature Tf(t), time average Reynolds number Re¯, drag coefficient C¯d, and Stanton number St¯ were calculated. In general, the drag coefficient and the Stanton number are smaller for the wing-shaped tubes than for the cylindrical tubes. However, with an increasing hydraulic diameter, these differences between both forms of tubes diminish. The time average values were further used to construct the drag coefficient and the Stanton number as polynomial functions C¯d(dh,Re¯) and St¯(dh,Re¯).
Effects of
ompA
Deletion on Expression of Type 1 Fimbriae in
Escherichia coli
K1 Strain RS218 and on the Association of
E. coli
with Human Brain Microvascular Endothelial Cells
Authors: Teng Ching-Hao , Xie Yi , Shin Sooan , Di Cello Francescopaolo , Paul-Satyaseela Maneesh , Cai Mian , Kim Kwang Sik
Published: September 2006

We have previously shown that outer membrane protein A (OmpA) and type 1 fimbriae are the bacterial determinants involved in
Escherichia coli
K1 binding to human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. In investigating the role of OmpA in
E. coli
K1 binding to HBMEC, we showed for the first time that
ompA
deletion decreased the expression of type 1 fimbriae in
E. coli
K1. Decreased expression of type 1 fimbriae in the
ompA
deletion mutant was largely the result of driving the
fim
promoter toward the type 1 fimbrial phase-OFF orientation. mRNA levels of
fimB
and
fimE
were found to be decreased with the OmpA mutant compared to the parent strain. Of interest, the
ompA
deletion further decreased the abilities of
E. coli
K1 to bind to and invade HBMEC under the conditions of fixing type 1 fimbria expression in the phase-ON or phase-OFF status. These findings suggest that the decreased ability of the OmpA mutant to interact with HBMEC is not entirely due to its decreased type 1 fimbrial expression and that OmpA and type 1 fimbriae facilitate the interaction of
E. coli
K1 with HBMEC at least in an additive manner.
Optimization of the Delivery of Heterologous Proteins by theSalmonella entericaSerovar Typhimurium Type III Secretion System for Vaccine Development
Authors: Chen Li-Mei , Briones Gabriel , Donis Ruben O. , Galán Jorge E.
Published: September 2006

Type III protein secretion systems, which are organelles with the capacity to deliver bacterial proteins into host cells, have been adapted to deliver heterologous antigens for vaccine development. A limitation of these antigen delivery systems is that some proteins are not amenable to secretion through this pathway. We show here that proteins from the simian and human immunodeficiency viruses that are not permissive for secretion through aSalmonella entericaserovar Typhimurium type III secretion system can be modified to travel this secretion pathway by introduction of discrete mutations. Proteins optimized for secretion were presented more efficiently via the major histocompatibility complex class I pathway and were able to induce a better immune response.
Overexpression, Purification, Characterization, and Pathogenicity of
Vibrio harveyi
Hemolysin VHH
Authors: Zhong Yingbin , Zhang Xiao-Hua , Chen Jixiang , Chi Zhenghao , Sun Boguang , Li Yun , Austin Brian
Published: September 2006

Vibrio harveyi
VHH hemolysin is a putative pathogenicity factor in fish. In this study, the hemolysin gene
vhhA
was overexpressed in
Escherichia coli
, and the purified VHH was characterized with regard to pH and temperature profiles, phospholipase activity, cytotoxicity, pathogenicity to flounder, and the signal peptide.
Actin Cytoskeleton-Dependent and -Independent Host Cell Invasion byTrypanosoma cruziIs Mediated by Distinct Parasite Surface Molecules
Authors: Ferreira Daniele , Cortez Mauro , Atayde Vanessa D. , Yoshida Nobuko
Published: September 2006

The disassembly of host cell actin cytoskeleton as a facilitator ofTrypanosoma cruziinvasion has been reported by some authors, while other workers claim that it instead inhibits internalization of the parasite. In this study we aimed at elucidating the basis of this discrepancy. We performed experiments with metacyclic trypomastigotes ofT. cruzistrains G and CL, which differ markedly in infectivity and enter target cells by engaging the surface molecules gp35/50 and gp82, respectively, which have signaling activity. Treatment of HeLa cells with the F-actin-disrupting drug cytochalasin D or latrunculin B inhibited the invasion by strain G but not the invasion by strain CL. In contrast to cells penetrated by strain CL, which were previously shown to have a disrupted actin cytoskeleton architecture, no such alteration was observed in HeLa cells invaded by strain G, and parasites were found to be closely associated with target cell actin. Coinfection with enteroinvasiveEscherichia coli(EIEC), which recruits host cell actin for internalization, drastically reduced entry of strain CL into HeLa cells but not entry of strain G. In contrast to gp82 in its recombinant form, which induces disruption of F-actin and inhibits EIEC invasion, purified mucin-like gp35/50 molecules promoted an increase in EIEC uptake by HeLa cells. These data, plus the finding that drugs that interfere with mammalian cell signaling differentially affect the internalization of metacyclic forms of strains G and CL, indicate that the host cell invasion mediated by gp35/50 is associated with signaling events that favor actin recruitment, in contrast to gp82-dependent invasion, which triggers the signaling pathways leading to disassembly of F-actin.
Reversible Deficiency of Antimicrobial Polypeptides in Bacterial Vaginosis
Authors: Valore Erika V. , Wiley Dorothy J. , Ganz Tomas
Published: September 2006

Bacterial vaginosis is a common condition associated with increased risk of sexually transmitted diseases, including human immunodeficiency virus infections. In contrast, vulvovaginal candidiasis has a much weaker association with sexually transmitted diseases. We found that vaginal lavage fluid from women with bacterial vaginosis is deficient in antimicrobial polypeptides and antimicrobial activity compared to fluid from healthy women or women with vulvovaginal candidiasis. Effective treatment normalized the concentrations of antimicrobial polypeptides in both bacterial vaginosis and in vulvovaginal candidiasis, suggesting that the abnormalities were a result of the diseases. Unlike in vulvovaginal candidiasis, the neutrophil attractant chemokine interleukin-8 (IL-8) was not increased in bacterial vaginosis, accounting for low concentrations of neutrophil-derived defensins in vaginal fluid. In organotypic cultures of human vaginal epithelium containing dendritic cells, treatment withLactobacillus jensenii, a typical vaginal resident, induced the synthesis of IL-8 mRNA and the epithelial human β-defensin-2 mRNA, but a typical bacterial vaginosis pathogen,Gardnerella vaginalis, had no effect. When the two bacteria were combined,Gardnerella vaginalisdid not interfere with the immunostimulatory effect ofLactobacillus jensenii. The loss of normal immunostimulatory flora in bacterial vaginosis is thus associated with a local deficiency of multiple innate immune factors, and this deficiency could predispose individuals to sexually transmitted diseases.
A DNA Prime-Modified Vaccinia Virus Ankara Boost Vaccine Encoding Thrombospondin-Related Adhesion Protein but Not Circumsporozoite Protein Partially Protects Healthy Malaria-Naive Adults against
Plasmodium falciparum
Sporozoite Challenge
Authors: Dunachie S. J. , Walther M. , Epstein J. E. , Keating S. , Berthoud T. , Andrews L. , Andersen R. F. , Bejon P. , Goonetilleke N. , Poulton I. , Webster D. P. , Butcher G. , Watkins K. , Sinden R. E. , Levine G. L. , Richie T. L. , Schneider J. , Kaslow D. , Gilbert S. C. , Carucci D. J. , Hill A. V. S.
Published: September 2006

The safety, immunogenicity, and efficacy of DNA and modified vaccinia virus Ankara (MVA) prime-boost regimes were assessed by using either thrombospondin-related adhesion protein (TRAP) with a multiple-epitope string ME (ME-TRAP) or the circumsporozoite protein (CS) of
Plasmodium falciparum
. Sixteen healthy subjects who never had malaria (malaria-naive subjects) received two priming vaccinations with DNA, followed by one boosting immunization with MVA, with either ME-TRAP or CS as the antigen. Immunogenicity was assessed by ex vivo gamma interferon (IFN-γ) enzyme-linked immunospot assay (ELISPOT) and antibody assay. Two weeks after the final vaccination, the subjects underwent
P. falciparum
sporozoite challenge, with six unvaccinated controls. The vaccines were well tolerated and immunogenic, with the DDM-ME TRAP regimen producing stronger ex vivo IFN-γ ELISPOT responses than DDM-CS. One of eight subjects receiving the DDM-ME TRAP regimen was completely protected against malaria challenge, with this group as a whole showing significant delay to parasitemia compared to controls (
P
= 0.045). The peak ex vivo IFN-γ ELISPOT response in this group correlated strongly with the number of days to parasitemia (
P
= 0.033). No protection was observed in the DDM-CS group. Prime-boost vaccination with DNA and MVA encoding ME-TRAP but not CS resulted in partial protection against
P. falciparum
sporozoite challenge in the present study.
Effects of Psa and F1 on the Adhesive and Invasive Interactions ofYersinia pestiswith Human Respiratory Tract Epithelial Cells
Authors: Liu Fengzhi , Chen Huaiqing , Galván Estela M. , Lasaro Melissa A. , Schifferli Dieter M.
Published: September 2006

Yersinia pestis, the causative agent of plague, expresses the Psa fimbriae (pH 6 antigen) in vitro and in vivo. To evaluate the potential virulence properties of Psa for pneumonic plague, anEscherichia colistrain expressing Psa was engineered and shown to adhere to three types of human respiratory tract epithelial cells. Psa binding specificity was confirmed with Psa-coated polystyrene beads and by inhibition assays. IndividualY. pestiscells were found to be able to express the capsular antigen fraction 1 (F1) concomitantly with Psa on their surface when analyzed by flow cytometry. To better evaluate the separate effects of F1 and Psa on the adhesive and invasive properties ofY. pestis, isogenic Δcaf(F1 genes), Δpsa, and ΔcafΔpsamutants were constructed and studied with the three respiratory tract epithelial cells. The Δpsamutant bound significantly less to all three epithelial cells compared to the parental wild-type strain and the Δcafand Δcaf Δpsamutants, indicating that Psa acts as an adhesin for respiratory tract epithelial cells. An antiadhesive effect of F1 was clearly detectable only in the absence of Psa, underlining the dominance of the Psa+phenotype. Both F1 and Psa inhibited the intracellular uptake ofY. pestis. Thus, F1 inhibits bacterial uptake by inhibiting bacterial adhesion to epithelial cells, whereas Psa seems to block bacterial uptake by interacting with a host receptor that doesn't direct internalization. The Δcaf Δpsadouble mutant bound and invaded all three epithelial cell types well, revealing the presence of an undefined adhesin(s) and invasin(s).
Down-Regulation of Key Virulence Factors Makes theSalmonella entericaSerovar TyphimuriumrfaHMutant a Promising Live-Attenuated Vaccine Candidate
Authors: Nagy Gábor , Danino Vittoria , Dobrindt Ulrich , Pallen Mark , Chaudhuri Roy , Emödy Levente , Hinton Jay C. , Hacker Jörg
Published: September 2006

Mutants ofSalmonella entericaserovar Typhimurium that lack the transcriptional regulator RfaH are efficient as live oral vaccines against salmonellosis in mice. We show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. In order to identify the relevant RfaH-dependent genes, the RfaH regulon was determined withS. entericaserovars Enteritidis and Typhimurium using whole-genomeSalmonellamicroarrays. As well as impacting the expression of genes involved in lipopolysaccharide (LPS) core and O-antigen synthesis, the loss of RfaH results in a marked down-regulation of SPI-4 genes, the flagellum/chemotaxis system, and type III secretion system 1. However, a proportion of these effects could have been the indirect consequence of the altered expression of genes required for LPS biosynthesis. Direct and indirect effects of therfaHmutation were dissociated by genome-wide transcriptional profiling of a structural deep-rough LPS mutant (waaG). We show that truncation of LPS itself is responsible for the decreased intracellular yield observed for ΔrfaHstrains. LPS mutants do not differ in replication ability; rather, they show increased susceptibility to antimicrobial peptides in the intracellular milieu. On the other hand, evidence that deletion ofrfaH, as well as some other genes involved in LPS biosynthesis, results in enhanced invasion of various mammalian cells is shown. Exposure of common minor antigens in the absence of serovar-specific antigens might be responsible for the observed cross-reactive nature of the elicited immune response upon vaccination. Increased invasiveness of theSalmonella rfaHmutant into antigen-presenting cells, combined with increased intracellular killing and the potential for raising a cross-protective immune response, renders therfaHmutant an ideal vaccine candidate.
Differential Role of Lipooligosaccharide ofNeisseria meningitidisin Virulence and Inflammatory Response during Respiratory Infection in Mice
Authors: Zarantonelli Maria Leticia , Huerre Michel , Taha Muhamed-Kheir , Alonso Jean-Michel
Published: September 2006

Meningococcal lipooligosaccharide (LOS) induces a strong proinflammatory response in humans during meningococcal infection. We analyzed the role of LOS in the inflammatory response and virulence during the early infectious process in a mouse model of meningococcal respiratory challenge. AnlpxAmutant strain (serogroup B) devoid of LOS (strain Z0204) could not persist in the lungs and did not invade the blood. The persistence in the lungs and invasion of the bloodstream by arfaDmutant expressing truncated LOS with only lipid A and 3-deoxy-d-manno-2-octulosonic acid molecules (strain Z0401) was intermediate between those of the wild-type and Z0204 strains. Both LOS mutants induced acute pneumonia with the presence of infiltrating polymorphonuclear leukocytes in lungs. Although tumor necrosis factor alpha production was reduced in mice infected with the mutant of devoid LOS, both LOS mutants induced production of other proinflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, and the murine IL-8 homolog KC. Together, these results suggest that meningococcal LOS plays a role during the early infectious and invasive process, and they further confirm that other, nonlipopolysaccharide components ofNeisseria meningitidismay significantly contribute to the inflammatory reaction of the host.
Measurement of Effector Protein Injection by Type III and Type IV Secretion Systems by Using a 13-Residue Phosphorylatable Glycogen Synthase Kinase Tag
Authors: Torruellas Garcia Julie , Ferracci Franco , Jackson Michael W. , Joseph Sabrina S. , Pattis Isabelle , Plano Lisa R. W. , Fischer Wolfgang , Plano Gregory V.
Published: September 2006

Numerous bacterial pathogens use type III secretion systems (T3SSs) or T4SSs to inject or translocate virulence proteins into eukaryotic cells. Several different reporter systems have been developed to measure the translocation of these proteins. In this study, a peptide tag-based reporter system was developed and used to monitor the injection of T3S and T4S substrates. The glycogen synthase kinase (GSK) tag is a 13-residue phosphorylatable peptide tag derived from the human GSK-3β kinase. Translocation of a GSK-tagged protein into a eukaryotic cell results in host cell protein kinase-dependent phosphorylation of the tag, which can be detected with phosphospecific GSK-3β antibodies. A series of expression plasmids encoding Yop-GSK fusion proteins were constructed to evaluate the ability of the GSK tag to measure the injection of Yops by the
Yersinia pestis
T3SS. GSK-tagged YopE, YopH, LcrQ, YopK, YopN, and YopJ were efficiently phosphorylated when translocated into HeLa cells. Similarly, the injection of GSK-CagA by the
Helicobacter pylori
T4SS into different cell types was measured via phosphorylation of the GSK tag. The GSK tag provides a simple method to monitor the translocation of T3S and T4S substrates.
Inhibition of Matrix Metalloproteinases Protects Mice from Ascending Infection and Chronic Disease Manifestations Resulting from UrogenitalChlamydia muridarumInfection
Authors: Imtiaz Muhammad T. , Schripsema Justin H. , Sigar Ira M. , Kasimos John N. , Ramsey Kyle H.
Published: September 2006

Matrix metalloproteinases (MMP) are a family of host-derived enzymes involved in the turnover of extracellular matrix molecules. We have previously reported enhanced expression of matrix metalloproteinases inChlamydia muridarumurogenital tract infection of female mice. Kinetics and patterns of MMP expression as well as enhanced expression in susceptible strains of mice in the prior study implied a role for MMP in pathogenesis. To explore this further, we infected a susceptible strain of mice (C3H/HeN) withC. muridarumand treated two groups of mice with either one of two chemical inhibitors of MMP (MMPi; captopril and a chemically modified tetracycline) and reserved infected sham-treated mice as controls. Neither of the treatments affected shedding of viable chlamydiae from the lower urogenital tract, but the administration of either MMPi protected mice from the formation of hydrosalpinx—a surrogate marker of oviduct occlusion and infertility. Interestingly, the mechanism of protection for mice treated with chemically modified tetracycline 3, appeared to be related to prevention of ascending upper genital tract infection. These results imply that MMP are involved in pathogenesis of chlamydial infection in this model by mediating ascension of the infection into the upper genital tract.
Protective Antigen as a Correlative Marker for Anthrax in Animal Models
Authors: Kobiler David , Weiss Shay , Levy Haim , Fisher Morly , Mechaly Adva , Pass Avi , Altboum Zeev
Published: September 2006

The most aggressive form of anthrax results from inhalation of airborne spores of
Bacillus anthracis
and usually progresses unnoticed in the early stages because of unspecific symptoms. The only reliable marker of anthrax is development of bacteremia, which increases with disease progress. Rapid diagnosis of anthrax is imperative for efficient treatment and cure. Herein we demonstrate that the presence and level of a bacterial antigen, the protective antigen (PA), a component of
B. anthracis
toxins, in host sera can serve as a reliable marker of infection. This was tested in two animal models of inhalation anthrax, rabbits and guinea pigs infected by intranasal instillation of Vollum spores. In both models, we demonstrated qualitative and quantitative correlations between levels of bacteremia and PA concentrations in the sera of sick animals. The average time to death in infected animals was about 16 h after the appearance of bacteremia, leaving a small therapeutic window. As the time required for immunodetection of PA can be very short, the use of this marker will be beneficial for faster diagnosis and treatment of inhalation anthrax.
Protection against Lethal Challenge withStreptococcus pneumoniaeIs Conferred by Aryl Hydrocarbon Receptor Activation but Is Not Associated with an Enhanced Inflammatory Response
Authors: Vorderstrasse Beth A. , Lawrence B. Paige
Published: September 2006

Streptococcus pneumoniaeis a common respiratory pathogen and a major cause of morbidity and mortality in humans, particularly in the elderly and young children. The pulmonary immune response toS. pneumoniaeis initiated very rapidly, and, ideally, innate immune responses are able to contain bacterial colonization. In the studies presented here, we sought to determine whether activation of the aryl hydrocarbon receptor (AhR) would protect mice from an otherwise lethal infection withS. pneumoniae. The rationale for this hypothesis is that, although most AhR agonists are potent immunosuppressants, AhR activation enhances the inflammatory response to pathogenic and nonpathogenic stimuli. Specifically, neutrophil numbers and levels of inflammatory cytokines are often increased in mice treated with the potent AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). To test the hypothesis, vehicle control- or TCDD-treated mice were intranasally infected withS. pneumoniae. Mortality, pulmonary bacterial burden, cytokine/chemokine levels, and influx of immune cells to the lung were analyzed at various times postinfection. As predicted, survival was substantially improved in the mice treated with TCDD, and the pulmonary bacterial burden was decreased. Surprisingly, however, there was no evidence suggesting that protection resulted from an enhanced inflammatory response. In fact, neutrophil numbers and inflammatory chemokines and cytokines were all decreased in the TCDD-treated mice relative to vehicle control-treated mice. This suggests that the protective effect of AhR activation is not the result of altered immune function but instead may reflect a direct effect on the response of lung cells to infection.
Non-random fluctuations in power output during self-paced exercise
Authors: Tucker R , Bester A , Lambert E V , Noakes T D , Vaughan C L , St Clair Gibson A
Published: September 2006

Objectives:To analyse the power output measured during a self-paced 20-km cycling time trial, during which power output was free to vary, in order to assess the level and characteristics of the variability in power output that occurred during the exercise bout.

Methods:Eleven well-trained cyclists performed a 20-km cycling time trial, during which power output was sampled every 200 m. Power spectrum analysis was performed on the power output data, and a fractal dimension was calculated for each trial using the Higuchi method.

Results:In all subjects, power output was maintained throughout the trial until the final kilometre, when it increased significantly, indicating the presence of a global pacing strategy. The power spectrum revealed the presence of 1/f-like scaling of power output and multiple frequency peaks during each trial, with the values of the frequency peaks changing over the course of the trial. The fractal dimension (D-score) was similar for all subjects over the 20-km trial and ranged between 1.5 and 1.9.

Conclusions:The presence of an end spurt in all subjects, 1/f-like scaling and multiple frequency peaks in the power output data indicate that the measured oscillations in power output during cycling exercise activity may not be system noise, but may rather be associated with system control mechanisms that are similar in different individuals.
Rupture of a flexor pollicis longus repair in a body builder through the use of an electronic muscle stimulator
Authors: Ansari A , Ramsey K W D R , Floyd D C
Published: September 2006

Involvement of tendons in hand lacerations is common, and immediate treatment involves exploration and primary repair. A programme of protected rehabilitation to allow healing and prevent rupture must follow. An unusual case is reported of tendon rupture in a body builder caused by use of an electronic muscle stimulator. Body builders should be warned about this mode of rupture, which has not been previously reported, during their rehabilitation.
A multidisciplinary selection model for youth soccer: the Ghent Youth Soccer Project
Authors: Vaeyens R , Malina R M , Janssens M , Van Renterghem B , Bourgois J , Vrijens J , Philippaerts R M
Published: September 2006

Objectives:To determine the relationships between physical and performance characteristics and level of skill in youth soccer players aged 12–16 years.

Methods:Anthropometry, maturity status, functional and sport-specific parameters were assessed in elite, sub-elite, and non-elite youth players in four age groups: U13 (n = 117), U14 (n = 136), U15 (n = 138) and U16 (n = 99).

Results:Multivariate analyses of covariance by age group with maturity status as the covariate showed that elite players scored better than the non-elite players on strength, flexibility, speed, aerobic endurance, anaerobic capacity and several technical skills (p<0.05). Stepwise discriminant analyses showed that running speed and technical skills were the most important characteristics in U13 and U14 players, while cardiorespiratory endurance was more important in U15 and U16 players. The results suggest that discriminating characteristics change with competitive age levels.

Conclusions:Characteristics that discriminate youth soccer players vary by age group. Talent identification models should thus be dynamic and provide opportunities for changing parameters in a long-term developmental context.
Use of the one-legged hyperextension test and magnetic resonance imaging in the diagnosis of active spondylolysis
Authors: Masci L , Pike J , Malara F , Phillips B , Bennell K , Brukner P
Published: September 2006

Background:Active spondylolysis is an acquired lesion in the pars interarticularis and is a common cause of low back pain in the young athlete.

Objectives:To evaluate whether the one-legged hyperextension test can assist in the clinical detection of active spondylolysis and to determine whether magnetic resonance imaging (MRI) is equivalent to the clinical gold standard of bone scintigraphy and computed tomography in the radiological diagnosis of this condition.

Methods:A prospective cohort design was used. Young active subjects with low back pain were recruited. Outcome measures included clinical assessment (one-legged hyperextension test) and radiological investigations including bone scintigraphy (with single photon emission computed tomography (SPECT)) and MRI. Computed tomography was performed if bone scintigraphy was positive.

Results:Seventy one subjects were recruited. Fifty pars interarticulares in 39 subjects (55%) had evidence of active spondylolysis as defined by bone scintigraphy (with SPECT). Of these, 19 pars interarticulares in 14 subjects showed a fracture on computed tomography. The one-legged hyperextension test was neither sensitive nor specific for the detection of active spondylolysis. MRI revealed bone stress in 40 of the 50 pars interarticulares in which it was detected by bone scintigraphy (with SPECT), indicating reduced sensitivity in detecting bone stress compared with bone scintigraphy (p  =  0.001). Conversely, MRI revealed 18 of the 19 pars interarticularis fractures detected by computed tomography, indicating concordance between imaging modalities (p  =  0.345). There was a significant difference between MRI and the combination of bone scintigraphy (with SPECT)/computed tomography in the radiological visualisation of active spondylolysis (p  =  0.002).

Conclusions:These results suggest that there is a high rate of active spondylolysis in active athletes with low back pain. The one-legged hyperextension test is not useful in detecting active spondylolysis and should not be relied on to exclude the diagnosis. MRI is inferior to bone scintigraphy (with SPECT)/computed tomography. Bone scintigraphy (with SPECT) should remain the first-line investigation of active athletes with low back pain followed by limited computed tomography if bone scintigraphy is positive.
Results of arthroscopic debridement for osteochondritis dissecans of the elbow
Authors: Rahusen F Th G , Brinkman J-M , Eygendaal D
Published: September 2006

Objective:To determine the clinical outcome of arthroscopic debridement for osteochondritis dissecans of the elbow.

Methods:A prospective cohort study was started in 2000; between 2000 and 2005, 15 patients (six male, nine female, mean age 28 years (range 16–49)) were treated for osteochondritis dissecans of the elbow with arthroscopic debridement. The lesion was graded during surgery using the classification of Baumgarten. The dominant side was operated on in seven of 15 patients, and all patients were involved in a sport in which the elbow is used extensively. Elbow function was assessed before and after surgery using the modified Andrews elbow scoring system (MAESS); pain was scored on a visual analogue scale (0, no pain; 10, severe pain). Evaluation was performed an average of 45 (range 18–59) months after surgery. Statistical analysis (Student’s t test) was carried out using SPSS statistical software. p<0.005 was considered significant.

Results:There were no complications. The range of motion did not improve significantly. The mean MAESS score improved from 65.5 (poor) before surgery to 90.8 (excellent) after (p<0.001). The mean level of pain at rest decreased from 3 to 1, and the level of pain after provocation decreased from 7 to 2 (p<0.001). All patients were able to return to work 3 months after surgery, and 80% were able to resume their pre-injury level of sport activity.

Conclusion:The clinical outcome after arthroscopic debridement for osteochondritis dissecans of the elbow shows good results, with pain relief during activities of daily living and sport. The function of the elbow, as reflected by the MAESS score, improved from poor to excellent. All patients in this series will be reviewed after 5 years to determine long-term results.
Spontaneous tetraplegia during weight training
Authors: Clewer G , Carmont M , Jaffray D
Published: September 2006

A case of tetraplegia due to weight training is presented. Emergency surgery revealed a huge C5/6 disc sequestration trapped within the canal by the posterior longitudinal ligament. The disc was removed and C5–C7 were fused using an iliac crest tricortical graft and stabilised. The patient made a good recovery and returned to sporting activity.
The validation of a novel activity monitor in the measurement of posture and motion during everyday activities
Authors: Grant P M , Ryan C G , Tigbe W W , Granat M H
Published: September 2006

Background:Accurate measurement of physical activity patterns can be used to identify sedentary behaviour and may facilitate interventions aimed at reducing inactivity.

Objective:To evaluate theactivPAL physical activity monitor as a measure of posture and motion in everyday activities using observational analysis as the criterion standard.

Methods:Wearing threeactivPAL monitors, 10 healthy participants performed a range of randomly assigned everyday tasks incorporating walking, standing and sitting. Each trial was captured on a digital camera and the recordings were synchronised with theactivPAL. The time spent in different postures was visually classified and this was compared with theactivPAL output.

Results:Intraclass correlation coefficients (ICC 2,1) for interdevice reliability ranged from 0.79 to 0.99. Using the Bland and Altman method, the mean percentage difference between theactivPAL monitor and observation for total time spent sitting was 0.19% (limits of agreement −0.68% to 1.06%) and for total time spent upright was −0.27% (limits of agreement −1.38% to 0.84%). The mean difference for total time spent standing was 1.4% (limits of agreement −6.2% to 9.1%) and for total time spent walking was −2.0% (limits of agreement −16.1% to 12.1%). A second-by-second analysis between observer and monitor found an overall agreement of 95.9%.

Conclusion:TheactivPAL activity monitor is a valid and reliable measure of posture and motion during everyday physical activities.
Tunneling of a diatomic molecule
Authors: Goodvin G L , Shegelski Mark RA
Published: September 2006

We summarize our study of a diatomic homonuclear molecule incident upon a potential barrier in one dimension [G.L. Goodvin and M.R.A. Shegelski. Phys. Rev. A, 71, 032719 (2005).]. We study various initial states for the molecule and allow transitions between vibrational states of the molecule during the process of tunneling. By applying an elegant method to solve this problem, we show that transmission resonances occur in several cases and that adding more binding energy levels for the molecule can tend to decrease the probability of tunneling. We also discuss the extension of our results to more realistic three-dimensional and experimental systems.PACS Nos.: 34.20.Cf, 03.65.Xp, 34.20.Gj, 34.50.Pi
Supersymmetric large extra dimensions and the cosmological constant problem
Authors: Burgess C P
Published: September 2006

This article briefly summarizes and reviews the motivations for — and the present status of — the proposal that the small size of the observed Dark Energy density can be understood in terms of the dynamical relaxation of two large extra dimensions within a supersymmetric higher dimensional theory.PACS Nos.: 31.15.Pf, 31.30.Jv, 32.10.Hq