bluuebunny/crossref_metadata_2025 huggingface dataset:
In VitroFunctional and Immunomodulatory Properties of the Lactobacillus helveticus MIMLh5-Streptococcus salivarius ST3 Association That Are Relevant to the Development of a Pharyngeal Probiotic Product
Authors: Taverniti Valentina , Minuzzo Mario , Arioli Stefania , Junttila Ilkka , Hämäläinen Sanna , Turpeinen Hannu , Mora Diego , Karp Matti , Pesu Marko , Guglielmetti Simone
Published: April 2012

The use of proper bacterial strains as probiotics for the pharyngeal mucosa is a potential prophylactic strategy for upper respiratory tract infections. In this context, we characterizedin vitrothe functional and immunomodulatory properties of the strainsLactobacillus helveticusMIMLh5 andStreptococcus salivariusST3 that were selected during previous investigations as promising pharyngeal probiotics. In this study, we demonstratedin vitrothat strains MIMLh5 and ST3, alone and in combination, can efficiently adhere to pharyngeal epithelial cells, antagonizeStreptococcus pyogenes, and modulate host innate immunity by inducing potentially protective effects. In particular, we found that the strains MIMLh5 and ST3 activate U937 human macrophages by significantly inducing the expression of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). Nonetheless, the induction of the anti-inflammatory interleukin-10 (IL-10) by MIMLh5 or ST3 was never lower than that of TNF-α, suggesting that these bacteria can potentially exert a regulatory rather than a proinflammatory effect. We also found that the strains MIMLh5 and ST3 induce cyclooxygenase 2 (COX-2) expression and demonstrated that toll-like receptor 2 (TLR-2) participates in the recognition of the strains MIMLh5 and ST3 by U937 cells. Finally, we observed that these microorganisms grow efficiently when cocultured in milk, suggesting that the preparation of a milk-based fermented product containing both MIMLh5 and ST3 can be a practical solution for the administration of these bacteria. In conclusion, we propose the combined use ofL. helveticusMIMLh5 andS. salivariusST3 for the preparation of novel products that display probiotic properties for the pharyngeal mucosa.
Lactobacillus equigenerosi Strain Le1 Invades Equine Epithelial Cells
Authors: Botha Marlie , Botes Marelize , Loos Ben , Smith Carine , Dicks Leon M. T.
Published: April 2012

Lactobacillus equigenerosi
strain Le1, a natural inhabitant of the equine gastrointestinal tract, survived pH 3.0 and incubation in the presence of 1.5% (wt/vol) bile salts for at least 2 h. Strain Le1 showed 8% cell surface hydrophobicity, 60% auto-aggregation, and 47% coaggregation with
Clostridium difficile
C6. Only 1% of the cells adhered to viable buccal epithelial cells and invaded the cells within 20 min after contact. Preincubation of strain Le1 in a buffer containing pronase prevented adhesion to viable epithelial cells. Preincubation in a pepsin buffer delayed invasion from 20 min to 1 h. Strain Le1 did not adhere to nonviable epithelial cells. Administration of
L. equigenerosi
Le1 (1 × 10
9
CFU per 50 kg body weight) to healthy horses did not increase white blood cell numbers. Differential white blood cell counts and aspartate aminotransferase levels remained constant. Glucose, lactate, cholesterol, and urea levels remained constant during administration with
L. equigenerosi
Le1 but decreased during the week after administration.
Isolation of Lactococcus lactis Mutants Simultaneously Resistant to the Cell Wall-Active Bacteriocin Lcn972, Lysozyme, Nisin, and Bacteriophage c2
Authors: Roces Clara , Courtin Pascal , Kulakauskas Saulius , Rodríguez Ana , Chapot-Chartier Marie-Pierre , Martínez Beatriz
Published: April 2012

Lactococcin 972 (Lcn972) is a nonlantibiotic bacteriocin that inhibits cell wall biosynthesis by binding to lipid II. In this work, two mutants resistant to Lcn972,
Lactococcus lactis
D1 and D1-20, with high (>320 arbitrary units [AU]/ml) and low (80 AU/ml) susceptibilities, respectively, have been isolated. Resistance to Lcn972 did not impose a burden to growth under laboratory conditions, nor did it substantially alter the physicochemical properties of the cell surface. However, the peptidoglycan of the mutants featured a higher content of muropeptides with tripeptide side chains than the wild-type strain, linking for the first time peptidoglycan remodelling to bacteriocin resistance. Moreover,
L. lactis
lacking a functional
d,d
-carboxypeptidase DacA (i.e., with a high content of pentapeptide side chain muropeptides) was shown to be more susceptible to Lcn972. Cross-resistance to lysozyme and nisin and enhanced susceptibility to penicillin G and bacitracin was also observed. Intriguingly, the Lcn972-resistant mutants were not infected by the lytic phage c2 and less efficiently infected by phage sk1. Lack of c2 infectivity was linked to a 22.6-kbp chromosomal deletion encompassing the phage receptor protein gene
pip
. The deletion also included maltose metabolic genes and the two-component system (TCS) F. However, a clear correlation between these genes and resistance to Lcn972 could not be clearly established, pointing to the presence of as-yet-unidentified mutations that account for Lcn972 resistance.
Determination of Wolbachia Diversity in Butterflies from Western Ghats, India, by a Multigene Approach
Authors: Salunke Bipinchandra K. , Salunkhe Rahul C. , Dhotre Dhiraj P. , Walujkar Sandeep A. , Khandagale Avinash B. , Chaudhari Rahul , Chandode Rakesh K. , Ghate Hemant V. , Patole Milind S. , Werren John H. , Shouche Yogesh S.
Published: April 2012

Members of the genus
Wolbachia
are intracellular bacteria that are widespread in arthropods and establish diverse symbiotic associations with their hosts, ranging from mutualism to parasitism. Here we present the first detailed analyses of
Wolbachia
in butterflies from India with screening of 56 species. Twenty-nine species (52%) representing five families were positive for
Wolbachia
. This is the first report of
Wolbachia
infection in 27 of the 29 species; the other two were reported previously. This study also provides the first evidence of infection in the family Papilionidae. A striking diversity was observed among
Wolbachia
strains in butterfly hosts based on five multilocus sequence typing (MLST) genes, with 15 different sequence types (STs). Thirteen STs are new to the MLST database, whereas ST41 and ST125 were reported earlier. Some of the same host species from this study carried distinctly different
Wolbachia
strains, whereas the same or different butterfly hosts also harbored closely related
Wolbachia
strains. Butterfly-associated STs in the Indian sample originated by recombination and point mutation, further supporting the role of both processes in generating
Wolbachia
diversity. Recombination was detected only among the STs in this study and not in those from the MLST database. Most of the strains were remarkably similar in their
wsp
genotype, despite divergence in MLST. Only two
wsp
alleles were found among 25 individuals with complete hypervariable region (HVR) peptide profiles. Although both
wsp
and MLST show variability, MLST gives better separation between the strains. Completely different STs were characterized for the individuals sharing the same
wsp
alleles.
Characterization of the Biosynthetic Operon for the Antibacterial Peptide Herbicolin in Pantoea vagans Biocontrol Strain C9-1 and Incidence in Pantoea Species
Authors: Kamber Tim , Lansdell Theresa A. , Stockwell Virginia O. , Ishimaru Carol A. , Smits Theo H. M. , Duffy Brion
Published: April 2012

Pantoea vagans
C9-1 is a biocontrol strain that produces at least two antibiotics inhibiting the growth of
Erwinia amylovora
, the causal agent of fire blight disease of pear and apple. One antibiotic, herbicolin I, was purified from culture filtrates of
P. vagans
C9-1 and determined to be 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine, also known as
N
ß
-epoxysuccinamoyl-DAP-valine. A plasposon library was screened for mutants that had lost the ability to produce herbicolin I. It was shown that mutants had reduced biocontrol efficacy in immature pear assays. The biosynthetic gene cluster in
P. vagans
C9-1 was identified by sequencing the flanking regions of the plasposon insertion sites. The herbicolin I biosynthetic gene cluster consists of 10 coding sequences (CDS) and is located on the 166-kb plasmid pPag2. Sequence comparisons identified orthologous gene clusters in
Pantoea agglomerans
CU0119 and
Serratia proteamaculans
568. A low incidence of detection of the biosynthetic cluster in a collection of 45
Pantoea
spp. from biocontrol, environmental, and clinical origins showed that this is a rare trait among the tested strains.
Characterization and Identification of Productivity-Associated Rhizobacteria in Wheat
Authors: Anderson Michael , Habiger Joshua
Published: April 2012

The rhizosphere is populated by a numerous and diverse array of rhizobacteria, and many impact productivity in largely unknown ways. Here we characterize the rhizobacterial community in a wheat variety categorized according to shoot biomass using 16S rRNA pyrosequencing abundance data. Plants were grown in homogenized field soil under greenhouse conditions, and DNA was extracted and pyrosequenced, resulting in 29,007 quality sequences. Operational taxonomic units (OTUs) that were significantly associated with biomass productivity were identified using an exact test adjusted for the false-discovery rate. The productivity deviation expressed as a percentage of the total mean square for regression (PMSR) was determined for each OTU. Out of 719 OTUs, 42 showed significant positive associations and 39 showed significant negative associations (
q
value, ≤0.05). OTUs with the greatest net positive associations, by genus, were as follows:
Duganella
, OTU 43 and OTU 3;
Janthinobacterium
, OTU 278;
Pseudomonas
, OTU 588; and
Cellvibrio
, OTU 1847. Those with negative associations were as follows:
Bacteria
, OTU 273;
Chryseobacterium
, OTU 508;
Proteobacteria
, OTU 249; and
Enterobacter
, OTU 357. Shoot biomass productivity was strongly correlated with the balance between the overall abundances of positive- and negative-productivity-associated OTUs. High-productivity rhizospheres contained 9.2 significant positives for every negatively associated rhizobacterium, while low-productivity rhizospheres showed 2.3 significant negatives for every positively associated rhizobacterium. Overall rhizobacterial community diversity as measured by the Chao1, Shannon, and Simpson indexes was nonlinearly related to productivity, closely fitting a wavelike cubic equation. We conclude that shoot biomass productivity is strongly related to the ratio of positive- to negative-productivity-associated rhizobacteria in the rhizosphere. This study identifies significant OTUs composing the productive and unproductive rhizobacterial communities.
Substrate-Induced Change in the Quaternary Structure of Type 2 Isopentenyl Diphosphate Isomerase from Sulfolobus shibatae
Authors: Nakatani Hitomi , Goda Shuichiro , Unno Hideaki , Nagai Takuya , Yoshimura Tohru , Hemmi Hisashi
Published: April 2012

Type 2 isopentenyl diphosphate isomerase catalyzes the interconversion between two active units for isoprenoid biosynthesis, i.e., isopentenyl diphosphate and dimethylallyl diphosphate, in almost all archaea and in some bacteria, including human pathogens. The enzyme is a good target for discovery of antibiotics because it is essential for the organisms that use only the mevalonate pathway to produce the active isoprene units and because humans possess a nonhomologous isozyme, type 1 isopentenyl diphosphate isomerase. However, type 2 enzymes were reportedly inhibited by mechanism-based drugs for the type 1 enzyme due to their surprisingly similar reaction mechanisms. Thus, a different approach is now required to develop new inhibitors specific to the type 2 enzyme. X-ray crystallography and gel filtration chromatography revealed that the enzyme from a thermoacidophilic archaeon,
Sulfolobus shibatae
, is in the octameric state at a high concentration. Interestingly, a part of the regions that are involved in the substrate binding in the previously reported tetrameric structures is integral to the formation of the tetramer-tetramer interface in the substrate-free octameric structure. Site-directed mutagenesis at such regions resulted in stabilization of the tetramer. Small-angle X-ray scattering, tryptophan fluorescence, and dynamic light scattering analyses showed that substrate binding causes the dissociation of an octamer into tetramers. This property, i.e., incompatibility between octamer formation and substrate binding, might provide clues to develop new specific inhibitors of the archaeal enzyme.
HmuP Is a Coactivator of Irr-Dependent Expression of Heme Utilization Genes in Bradyrhizobium japonicum
Authors: Escamilla-Hernandez Rosalba , O'Brian Mark R.
Published: April 2012

Utilization of heme as an iron source by
Bradyrhizobium japonicum
involves induction of the outer membrane heme receptor gene
hmuR
and other genes within the heme utilization locus. Here, we discovered the
hmuP
gene located upstream of
hmuR
and transcribed divergently from it along with
hmuTUV
.
hmuP
encodes a small protein that accumulated under iron limitation and is transcriptionally controlled by the global iron-responsive regulator Irr, as were all genes within the heme utilization locus. Cross-linking and immunoprecipitation experiments showed that Irr occupies the
hmuR
-
hmuP
promoter
in vivo
. An
hmuP
mutant did not grow on heme as an iron source, but retained the ability to use ferric chloride. Correspondingly, induction of
hmuR
mRNA under iron limitation was severely diminished in an
hmuP
strain, but other genes within the Irr regulon were unaffected. HmuP occupied the
hmuR
-
hmuP
promoter, and thus it plays a direct regulatory role in gene expression. HmuP was not required for Irr occupancy, nor was ectopic expression of
hmuP
from an Irr-independent promoter sufficient to induce the
hmuR
gene. Thus, both HmuP and Irr occupancy are necessary for
hmuR
induction. We suggest that HmuP is a coactivator of Irr-dependent expression of
hmuR
.
Identification of ZapD as a Cell Division Factor That Promotes the Assembly of FtsZ in Escherichia coli
Authors: Durand-Heredia Jorge , Rivkin Eugene , Fan Guoxiang , Morales Jorge , Janakiraman Anuradha
Published: April 2012

The tubulin homolog FtsZ forms a polymeric membrane-associated ring structure (Z ring) at midcell that establishes the site of division and provides an essential framework for the localization of a multiprotein molecular machine that promotes division in
Escherichia coli
. A number of regulatory proteins interact with FtsZ and modulate FtsZ assembly/disassembly processes, ensuring the spatiotemporal integrity of cytokinesis. The Z-associated proteins (ZapA, ZapB, and ZapC) belong to a group of FtsZ-regulatory proteins that exhibit functionally redundant roles in stabilizing FtsZ-ring assembly by binding and bundling polymeric FtsZ at midcell. In this study, we report the identification of ZapD (YacF) as a member of the
E. coli
midcell division machinery. Genetics and cell biological evidence indicate that ZapD requires FtsZ but not other downstream division proteins for localizing to midcell, where it promotes FtsZ-ring assembly via molecular mechanisms that overlap with ZapA. Biochemical evidence indicates that ZapD directly interacts with FtsZ and promotes bundling of FtsZ protofilaments. Similarly to ZapA, ZapB, and ZapC, ZapD is dispensable for division and therefore belongs to the growing group of FtsZ-associated proteins in
E. coli
that aid in the overall fitness of the division process.
Pangenomic Study of Corynebacterium diphtheriae That Provides Insights into the Genomic Diversity of Pathogenic Isolates from Cases of Classical Diphtheria, Endocarditis, and Pneumonia
Authors: Trost Eva , Blom Jochen , de Castro Soares Siomar , Huang I-Hsiu , Al-Dilaimi Arwa , Schröder Jasmin , Jaenicke Sebastian , Dorella Fernanda A. , Rocha Flavia S. , Miyoshi Anderson , Azevedo Vasco , Schneider Maria P. , Silva Artur , Camello Thereza C. , Sabbadini Priscila S. , Santos Cíntia S. , Santos Louisy S. , Hirata Raphael , Mattos-Guaraldi Ana L. , Efstratiou Androulla , Schmitt Michael P. , Ton-That Hung , Tauch Andreas
Published: April 2012

Corynebacterium diphtheriae
is one of the most prominent human pathogens and the causative agent of the communicable disease diphtheria. The genomes of 12 strains isolated from patients with classical diphtheria, endocarditis, and pneumonia were completely sequenced and annotated. Including the genome of
C. diphtheriae
NCTC 13129, we herewith present a comprehensive comparative analysis of 13 strains and the first characterization of the pangenome of the species
C. diphtheriae
. Comparative genomics showed extensive synteny and revealed a core genome consisting of 1,632 conserved genes. The pangenome currently comprises 4,786 protein-coding regions and increases at an average of 65 unique genes per newly sequenced strain. Analysis of prophages carrying the diphtheria toxin gene
tox
revealed that the toxoid vaccine producer
C. diphtheriae
Park-Williams no. 8 has been lysogenized by two copies of the ω

tox

+
phage, whereas
C. diphtheriae
31A harbors a hitherto-unknown
tox
+
corynephage. DNA binding sites of the
tox
-controlling regulator DtxR were detected by genome-wide motif searches. Comparative content analysis showed that the DtxR regulons exhibit marked differences due to gene gain, gene loss, partial gene deletion, and DtxR binding site depletion. Most predicted pathogenicity islands of
C. diphtheriae
revealed characteristics of horizontal gene transfer. The majority of these islands encode subunits of adhesive pili, which can play important roles in adhesion of
C. diphtheriae
to different host tissues. All sequenced isolates contain at least two pilus gene clusters. It appears that variation in the distributed genome is a common strategy of
C. diphtheriae
to establish differences in host-pathogen interactions.
Genetic Analysis of 15 Protein Folding Factors and Proteases of the Escherichia coli Cell Envelope
Authors: Weski Juliane , Ehrmann Michael
Published: April 2012

Each cell hosts thousands of proteins that vary greatly in abundance, structure, and chemical properties. To ensure that all proteins are biologically active and properly localized, efficient quality control systems have evolved. While the structure, function, and regulation of some individual protein folding factors and proteases were resolved up to atomic resolution, others remain poorly characterized. In addition, little is known about which factors are required for viability under specific stress conditions. We therefore determined the physiological implications of 15 factors of theE. colicell envelope by an integrated genetic approach comprising phenotypic analyses. Our data indicate thatsurAandtspnull mutations are a lethal combination in rich medium, thatsurA dsbAandsurA dsbCdouble mutants are temperature sensitive, and thatsurA ptrA,surA yfgC,dsbA fkpA,degP tsp,degP ppiD,tsp ppiD, anddegP dsbAdouble mutants are temperature sensitive in rich medium containing 0.5 M NaCl, whiledegP dsbA,degP yfgC,tsp ydgD, anddegP tspdouble mutants do not grow in the presence of SDS/EDTA. Furthermore, we show that indegP dsbA,degP tsp, anddegP yfgCdouble mutants a subpopulation of LamB exists as unfolded monomers. In addition,dsbAnull mutants expressed lower levels of the outer membrane proteins LptD, LamB, FhuA, and OmpW while FhuA levels were reduced insurAsingle anddegP ppiDdouble mutants. Lower FhuA levels indegP ppiDstrains depend on Tsp, since in atsp degP ppiDtriple mutant FhuA levels are restored.
Osmolality-Dependent Relocation of Penicillin-Binding Protein PBP2 to the Division Site in Caulobacter crescentus
Authors: Hocking Jason , Priyadarshini Richa , Takacs Constantin N. , Costa Teresa , Dye Natalie A. , Shapiro Lucy , Vollmer Waldemar , Jacobs-Wagner Christine
Published: April 2012

The synthesis of the peptidoglycan cell wall is carefully regulated in time and space. In nature, this essential process occurs in cells that live in fluctuating environments. Here we show that the spatial distributions of specific cell wall proteins in
Caulobacter crescentus
are sensitive to small external osmotic upshifts. The penicillin-binding protein PBP2, which is commonly branded as an essential cell elongation-specific transpeptidase, switches its localization from a dispersed, patchy pattern to an accumulation at the FtsZ ring location in response to osmotic upshifts as low as 40 mosmol/kg. This osmolality-dependent relocation to the division apparatus is initiated within less than a minute, while restoration to the patchy localization pattern is dependent on cell growth and takes 1 to 2 generations. Cell wall morphogenetic protein RodA and penicillin-binding protein PBP1a also change their spatial distribution by accumulating at the division site in response to external osmotic upshifts. Consistent with its ecological distribution,
C. crescentus
displays a narrow range of osmotolerance, with an upper limit of 225 mosmol/kg in minimal medium. Collectively, our findings reveal an unsuspected level of environmental regulation of cell wall protein behavior that is likely linked to an ecological adaptation.
Molecular Basis of Yersinia enterocolitica Temperature-Dependent Resistance to Antimicrobial Peptides
Authors: Reinés Mar , Llobet Enrique , Llompart Catalina M. , Moranta David , Pérez-Gutiérrez Camino , Bengoechea José A.
Published: April 2012

Antimicrobial peptides (APs) belong to the arsenal of weapons of the innate immune system against infections. In the case of Gram-negative bacteria, APs interact with the anionic lipid A moiety of the lipopolysaccharide (LPS). In yersiniae most virulence factors are temperature regulated. Studies from our laboratory demonstrated that
Yersinia enterocolitica
is more susceptible to polymyxin B, a model AP, when grown at 37°C than at 22°C (J. A. Bengoechea, R. Díaz, and I. Moriyón, Infect. Immun. 64:4891–4899, 1996), and here we have extended this observation to other APs, not structurally related to polymyxin B. Mechanistically, we demonstrate that the lipid A modifications with aminoarabinose and palmitate are downregulated at 37°C and that they contribute to AP resistance together with the LPS O-polysaccharide. Bacterial loads of lipid A mutants in Peyer's patches, liver, and spleen of orogastrically infected mice were lower than those of the wild-type strain at 3 and 7 days postinfection. PhoPQ and PmrAB two-component systems govern the expression of the loci required to modify lipid A with aminoarabinose and palmitate, and their expressions are also temperature regulated. Our findings support the notion that the temperature-dependent regulation of loci controlling lipid A modifications could be explained by H-NS-dependent negative regulation alleviated by RovA. In turn, our data also demonstrate that PhoPQ and PmrAB regulate positively the expression of
rovA
, the effect of PhoPQ being more important. However,
rovA
expression reached wild-type levels in the
phoPQ pmrAB
mutant background, hence indicating the existence of an unknown regulatory network controlling
rovA
expression in this background.
The Pseudomonas aeruginosa Global Regulator VqsR Directly Inhibits QscR To Control Quorum-Sensing and Virulence Gene Expression
Authors: Liang Haihua , Deng Xin , Ji Quanjiang , Sun Fei , Shen Tuo , He Chuan
Published: April 2012

The opportunistic pathogen
Pseudomonas aeruginosa
has at least three quorum-sensing (QS) systems, including the acyl-homoserine lactone (acyl-HSL)-mediated
las
and
rhl
systems, as well as the 2-alkyl-4(1H)-quinolone (AHQ) signal-based system. A group of key regulators of these QS systems have been identified, such as
qteE
,
vqsM
,
vqsR
, and
vfr
. However, the underlying regulatory mechanisms of these QS systems are not yet fully understood. Here, using electrophoretic mobility shift assays, we demonstrated that VqsR indirectly regulates acyl-HSL systems but specifically binds to the
qscR
promoter region, which indicates that VqsR influences QS-controlled pathways through QscR. Through a dye-based DNase I footprint assay, we showed that VqsR interacts with an inverted repeat (IR) motif (TCGCCN
8
GGCGA, where N is any nucleotide) in the promoter region of
qscR
. A genome-wide search identified 50 other promoter regions carrying the same putative IR motif. The recombinant VqsR protein exists as a homodimer in solution. In addition, using a
qscR
-
lux
reporter assay and Northern blot hybridization, we found that the transcription level of
qscR
increased 4-fold in the
vqsR
deletion strain compared to the wild-type PAO1 strain, indicating
vqsR
as a negative regulator of
qscR
. Taken together, these findings provide new insights into the complex regulation network of QS systems in
P. aeruginosa
.
Cost and clinical effectiveness of MRI in occult scaphoid fractures: a randomised controlled trial
Authors: Patel Nirav K , Davies Nigel , Mirza Zulfiquar , Watson Martin
Published: April 2012

Background

Clinical and radiographic diagnoses of scaphoid fractures are often challenging at the time of injury. Patients are therefore usually reassessed which has cost implications. Various investigations exist but MRI has been suggested as effective in diagnosing these injuries early.

Aim

To determine whether early MRI in suspected occult scaphoid fractures is more clinically and cost effective than conventional management with immobilisation and reassessment.

Methods

All patients presenting to the Emergency Department at a district general hospital with a suspected occult scaphoid fracture were randomised into two groups, MRI (early scan of the wrist, discharged if no injury) and control (reassessment in clinic).

Results

84 patients were randomised into MRI (45) and control (39) groups. There were no baseline differences apart from greater dominant hand injuries in the MRI group (62% (26) vs 36% (14), p=0.02). There were three (6.7%) scaphoid fractures in the MRI group and four (10.3%) in the control group (p=0.7). More fractures (15.6% (7) vs 5.1% (2), p=0.9) and other injuries were detected in the MRI group who had fewer mean clinic appointments (1.1±0.5 vs 2.3±0.8, p=0.001) and radiographs (1.2±0.8 vs 1.7±1.1, p=0.03). Mean management costs were £504.13 (MRI) and £532.87 (control) (p=0.9). The MRI group had better pain and satisfaction scores (not significant) with comparable time off work and sporting activities.

Conclusion

Early MRI in occult scaphoid fractures is marginally cost saving compared with conventional management and may reduce potentially large societal costs of unnecessary immobilisation. It enables early detection and appropriate treatment of scaphoid and other injuries.
Burnout among advanced life support paramedics in Johannesburg, South Africa
Authors: Stassen Willem , Van Nugteren Benjamin , Stein Christopher
Published: April 2012

Objectives

To establish the prevalence of burnout among advanced life support (ALS) paramedics in Johannesburg, South Africa and assess the relationship between burnout and a number of demographic characteristics of the sampled ALS paramedics.

Design

Cross-sectional internet-based survey.

Method

Survey invitations were sent via email to 98 registered ALS paramedics in the Johannesburg area. The survey questionnaire was created by combining the Copenhagen Burnout Inventory (CBI) with numerous distractor questions. Burnout was defined as a CBI score >50. Descriptive analysis was performed and results subjected to Chi-square testing in order to establish dependencies between burnout scores and demographic factors.

Results

A 46% (n=45) response rate was obtained. Forty responses were eligible for analysis. 30% of these respondents had total burnout according to their CBI score, while 63% exhibited some degree of burnout in one of the CBI subcategories. The results of the subcategory analyses showed that 23% of respondents experienced burnout in the patient care-related category, 38% experienced burnout in the work-related category and 53% experienced burnout in the personal burnout category. There were no statistical differences in the burnout scores according to gender (p=0.292), position held (p=0.193), employment sector (p=0.414), years of experience (p=0.228) or qualification (p=0.846). Distractor questions showed that paramedics feel overworked, undervalued, poorly remunerated and unsupported by their superiors.

Conclusion

This sample of Johannesburg-based paramedics had a greater prevalence of burnout compared with their international counterparts. Further research is needed to identify the true extent of this problem.
Mathematical and drug calculation abilities of paramedic students
Authors: Eastwood Kathryn , Boyle Malcolm J , Williams Brett
Published: April 2012

Aim

The objective of this study was to determine if undergraduate paramedics could accurately perform common drug calculations and basic mathematical computations normally required in the workplace.

Method

A descriptive paper-based questionnaire collecting demographical data, student attitudes regarding their drug calculation performance, and answers to a series of basic mathematical and drug calculation questions was administered to undergraduate paramedic students.

Results

The mean score was 39.5% with only 3.3% of students (n=3) scoring greater than 90%, and 63%(n=58) scoring 50% or less. Conceptual errors made up 48.5%, arithmetical 31.1% and computational 17.4%.

Conclusion

This study suggests undergraduate paramedics have deficiencies in performing accurate calculations with conceptual errors indicating a fundamental lack of mathematical understanding.
Should an alternative to the Glasgow Coma Scale be taught to paramedic students?
Authors: Winship Christian , Williams Brett , Boyle Malcolm J
Published: April 2012

Background

The accurate assessment of a patient's conscious state using the Glasgow Coma Scale (GCS) is an important skill for paramedics as it may determine the patient's initial and ongoing management. The objective of this study was to determine if undergraduate paramedic students from a large Australian University were able to accurately interpret a variety of conscious states.

Methods

A prospective double-blinded observational pilot study requiring students to interpret the conscious state of four adult patients using the GCS by viewing a simulation DVD package.

Results

There were 137 students who participated in the study, of whom 65% (n=87) were female students. The results demonstrated that undergraduate paramedic students were unable to accurately interpret a number of patient conscious states with only 20% and 37% of students able to accurately identify the GCS of patients 2 (GCS=12) and 3 (GCS=7). The motor component of the GCS appeared to be the component where the least accurate interpretation occurred, with only 47% of students being able to accurately identify the criteria that patient 3 displayed. Participants were however able to accurately interpret the GCS of both patient 1 (GCS=14) (86%) and patient 4 (GCS=15) (92%).

Conclusion

This pilot study demonstrates that undergraduate paramedic students from an Australian university were unable to accurately interpret a patient's conscious state if their GCS score was <14. These findings have provided academic staff with important information for considering alternative teaching and learning strategies and approaches in conscious state assessment in current paramedic curricula.
Gastroenterology and the provision of care to Panjabi patients in the UK: Table 1
Authors: Mayberry John Francis , Farrukh Affifa
Published: April 2012

Panjabi is spoken by 1.3 million people in the UK. It is the second most common language used in the country and is the first choice of 75% of Panjabis. It is becoming more common. For many patients it forms part of the barrier which limits access to gastrointestinal services. The provision of appropriate support services is woeful and yet seldom leads to formal complaints. This review considers the impact of gastrointestinal disorders on the Panjabi community and assesses some of the interventions that could be developed to ensure equity of care.
Feasibility and experience of nurse-led ultrasound-guided percutaneous liver biopsy: Table 1
Authors: Farrington Elizabeth Anne , Maskell Giles , Hussaini Hyder Syed
Published: April 2012

The demand for collaborative and innovative clinical practitioners to act as leaders in healthcare remains strong as many challenges are faced including rising costs, shortage of professionals, the introduction of new technology and difficulties with access to care. Nurses in advanced nursing practice are well positioned to respond to this, playing a key role in building nursing knowledge, advancing the nursing profession and contributing to sustainable and effective healthcare systems. Percutaneous liver biopsy (PLB) is an essential tool used for diagnosis and management in liver disease, being most commonly performed by consultant gastroenterologists, hepatologists and radiologists. While invasive and with complications PLB is a simple, cost-effective procedure that can be undertaken at the bedside. Our study demonstrates that an advanced nurse practitioner (ANP) with a sound working knowledge of hepatology and familiarity with indications, methods and risks of PLB procedure can be trained to perform ultrasound-guided liver biopsy both safely and effectively.
New challenges in viral hepatitis
Authors: Thomas David , Zoulim Fabien
Published: April 2012

Over the past few decades there has been remarkable progress in viral hepatitis. Beginning with discovery of the viral agents, we now have reliable methods to diagnose and monitor all hepatitis virus infections, as well significant advances in treatment and prevention. Nonetheless, important challenges remain. This supplement to Gut looks forward to the next generation of challenges in the field of viral hepatitis, and this introductory article highlights several key issues.
Validity of smoke alarm self-report measures and reasons for over-reporting
Authors: Stepnitz Rebecca , Shields Wendy , McDonald Eileen , Gielen Andrea
Published: April 2012

Objectives

Many residential fire deaths occur in homes with no or non-functioning smoke alarms (SAs). Self-reported SA coverage is high, but studies have found varying validity for self-report measures. The authors aim to: (1) determine over-reporting of coverage, (2) describe socio-demographic correlates of over-reporting and (3) report reasons for over-reporting.

Methods

The authors surveyed 603 households in a large, urban area about fire safety behaviours and then tested all SAs in the home. 23 participants who over-reported their SA coverage were telephoned and asked about why they had misreported.

Results

Full coverage was reported in 70% of households but observed in only 41%, with a low positive predictive value (54.2%) for the self-report measure. Most over-reporters assumed alarms were working because they were mounted or did not think a working alarm in a basement or attic was needed to be fully protected.

Conclusions

If alarms cannot be tested, researchers or those counselling residents on fire safety should carefully probe self-reported coverage. Our findings support efforts to equip more homes with hard-wired or 10 year lithium battery alarms to reduce the need for user maintenance.
Imaging in children presenting with acute neurological deficit: stroke
Authors: Rasalkar Darshana D , Chu Winnie C W
Published: April 2012

Neurological deficits in the paediatric age group are much rarer than in adults; however, it is an urgent condition that relies heavily on imaging for a prompt accurate diagnosis. Neurological deficits caused by cerebrovascular diseases are defined as stroke, whereas conditions manifesting with neurological deficits without underlying cerebrovascular diseases are referred to as stroke mimics. To the best of the authors' knowledge, there is a lack of systematic pictorial review that collectively describes the imaging of neurological deficit in children. The purpose of the present series is to discuss the causes and imaging appearance of neurological deficits in childhood, based on the experience of a tertiary paediatric referral centre These are broadly categorised into stroke, infection, inflammation, metabolic disorder, cerebral neoplasms and drug poisoning. Different entities of stroke and their respective imaging findings are discussed. Paediatric stroke can further be divided into arterial ischaemic stroke, sino-venous stroke, haemorrhagic stroke and hypoxic–ischaemic encephalopathy.
THE GEOMETRY OF THE HANDLEBODY GROUPS I: DISTORTION
Authors: HAMENSTÄDT URSULA , HENSEL SEBASTIAN
Published: April 2012

We show that the mapping class group of a handlebody V of genus at least 2 (with any number of marked points or spots) is exponentially distorted in the mapping class group of its boundary surface ∂V. The same holds true for solid tori V with at least two marked points or spots.
Intestinal epithelial CD98 synthesis specifically modulates expression of colonic microRNAs during colitis
Authors: Charania Moiz A. , Ayyadurai Saravanan , Ingersoll Sarah A. , Xiao Bo , Viennois Emilie , Yan Yutao , Laroui Hamed , Sitaraman Shanthi V. , Merlin Didier
Published: April 2012

The transmembrane glycoprotein CD98 is known to be involved in intestinal inflammation. In the present study, we found that CD98 overexpression in intestinal epithelial cells does not normally affect the expression of colonic (epithelial and immune cell) microRNAs (miRNAs), small noncoding RNAs that posttranscriptionally regulate a wide variety of biological processes. However, upon dextran sulfate sodium (DSS) treatment, the expression of several colonic miRNAs, but not miRNAs from other tissues such as liver and spleen, were differentially regulated in mice overexpressing CD98 in epithelial cells compared with wild-type (WT) animals. For example, the level of colonic miRNA 132 was not affected by DSS treatment in WT animals but was upregulated in mice overexpressing CD98 in intestinal epithelial cells. Other colonic miRNAs, including colonic miRNA 23a and 23b, were downregulated in WT animals after DSS treatment but not in colonic epithelial cell CD98-overexpressing mice. Interestingly, the expression of potential miRNA target genes affected intestinal epithelial cells that overexpress CD98 and cell types that did not overexpress CD98 but were in close proximity to CD98-overexpressing intestinal epithelial cells. Taken together, these observations show that the combination of an inflammatory context and intestinal epithelial cell expression of CD98 affects the regulation of miRNA expression in colonic epithelial and immune cells. This is new evidence that protein expression modulates miRNA expression and suggests the existence of regulatory crosstalk between proteins and miRNAs in diseases such as colitis.
Cyclooxygenase inhibition augments central blood pressure and aortic wave reflection in aging humans
Authors: Barnes Jill N. , Casey Darren P. , Hines Casey N. , Nicholson Wayne T. , Joyner Michael J.
Published: April 2012

The augmentation index and central blood pressure increase with normal aging. Recently, cyclooxygenase (COX) inhibitors, commonly used for the treatment of pain, have been associated with transient increases in the risk of cardiovascular events. We examined the effects of the COX inhibitor indomethacin (Indo) on central arterial hemodynamics and wave reflection characteristics in young and old healthy adults. High-fidelity radial arterial pressure waveforms were measured noninvasively by applanation tonometry before (control) and after Indo treatment in young (25 ± 5 yr, 7 men and 6 women) and old (64 ± 6 yr, 5 men and 6 women) subjects. Aortic systolic (control: 115 ± 3 mmHg vs. Indo: 125 ± 5 mmHg, P < 0.05) and diastolic (control: 74 ± 2 mmHg vs. Indo: 79 ± 3 mmHg, P < 0.05) pressures were elevated after Indo treatment in older subjects, whereas only diastolic pressure was elevated in young subjects (control: 71 ± 2 mmHg vs. Indo: 76 ± 1 mmHg, P < 0.05). Mean arterial pressure increased in both young and old adults after Indo treatment ( P < 0.05). The aortic augmentation index and augmented pressure were elevated after Indo treatment in older subjects (control: 30 ± 5% vs. Indo 36 ± 6% and control 12 ± 1 mmHg vs. Indo: 18 ± 2 mmHg, respectively, P < 0.05), whereas pulse pressure amplification decreased (change: 8 ± 3%, P < 0.05). In addition, older subjects had a 61 ± 11% increase in wasted left ventricular energy after Indo treatment ( P < 0.05). In contrast, young subjects showed no significant changes in any of the variables of interest. Taken together, these results demonstrate that COX inhibition with Indo unfavorably increases central wave reflection and augments aortic pressure in old but not young subjects. Our results suggest that aging individuals have a limited ability to compensate for the acute hemodynamic changes caused by systemic COX inhibition.
Role of connexin-43 in protective PI3K-Akt-GSK-3β signaling in cardiomyocytes
Authors: Ishikawa Satoko , Kuno Atsushi , Tanno Masaya , Miki Takayuki , Kouzu Hidemichi , Itoh Takahito , Sato Tatsuya , Sunaga Daisuke , Murase Hiromichi , Miura Tetsuji
Published: April 2012

Sarcolemmal connexin-43 (Cx43) and mitochondrial Cx43 play distinct roles: formation of gap junctions and production of reactive oxygen species (ROS) for redox signaling. In this study, we examined the hypothesis that Cx43 contributes to activation of a major cytoprotective signal pathway, phosphoinositide 3-kinase (PI3K)-Akt-glycogen synthase kinase-3β (GSK-3β) signaling, in cardiomyocytes. A δ-opioid receptor agonist {[d-Ala2,d-Leu5]enkephalin acetate (DADLE)}, endothelin-1 (ET-1), and insulin-like growth factor-1 (IGF-1) induced phosphorylation of Akt and GSK-3β in H9c2 cardiomyocytes. Reduction of Cx43 protein to 20% of the normal level by Cx43 small interfering RNA abolished phosphorylation of Akt and GSK-3β induced by DADLE or ET-1 but not that induced by IGF-1. DADLE and IGF-1 protected H9c2 cells from necrosis after treatment with H2O2 or antimycin A. The protection by DADLE or ET-1, but not that by IGF-1, was lost by reduction of Cx43 protein expression. In contrast to Akt and GSK-3β, PKC-ε, ERK and p38 mitogen-activated protein kinase were phosphorylated by ET-1 in Cx43-knocked-down cells. Like diazoxide, an activator of the mitochondrial ATP-sensitive K+ channel, DADLE and ET-1 induced significant ROS production in mitochondria, although such an effect was not observed for IGF-1. Cx43 knockdown did not attenuate the mitochondrial ROS production by DADLE or ET-1. Cx43 was coimmunoprecipitated with the β-subunit of G protein (Gβ), and knockdown of Gβ mimicked the effect of Cx43 knockdown on ET-1-induced phosphorylation of Akt and GSK-3β. These results suggest that Cx43 contributes to activation of class IB PI3K in PI3K-Akt-GSK-3β signaling possibly as a cofactor of Gβ in cardiomyocytes.
PEG-albumin supraplasma expansion is due to increased vessel wall shear stress induced by blood viscosity shear thinning
Authors: Sriram Krishna , Tsai Amy G. , Cabrales Pedro , Meng Fantao , Acharya Seetharama A. , Tartakovsky Daniel M. , Intaglietta Marcos
Published: April 2012

We studied the extreme hemodilution to a hematocrit of 11% induced by three plasma expanders: polyethylene glycol (PEG)-conjugated albumin (PEG-Alb), 6% 70-kDa dextran, and 6% 500-kDa dextran. The experimental component of our study relied on microelectrodes and cardiac output to measure both the rheological properties of plasma-expander blood mixtures and nitric oxide (NO) bioavailability in vessel walls. The modeling component consisted of an analysis of the distribution of wall shear stress (WSS) in the microvessels. Our experiments demonstrated that plasma expansion with PEG-Alb caused a state of supraperfusion with cardiac output 40% above baseline, significantly increased NO vessel wall bioavailability, and lowered peripheral vascular resistance. We attributed this behavior to the shear thinning nature of blood and PEG-Alb mixtures. To substantiate this hypothesis, we developed a mathematical model of non-Newtonian blood flow in a vessel. Our model used the Quemada rheological constitutive relationship to express blood viscosity in terms of both hematocrit and shear rate. The model revealed that the net effect of the hemodilution induced by relatively low-viscosity shear thinning PEG-Alb plasma expanders is to reduce overall blood viscosity and to increase the WSS, thus intensifying endothelial NO production. These changes act synergistically, significantly increasing cardiac output and perfusion due to lowered overall peripheral vascular resistance.
Platelets induce endothelial tissue factor expression in a mouse model of acid-induced lung injury
Authors: Emin Memet T. , Sun Li , Huertas Alice , Das Shonit , Bhattacharya Jahar , Bhattacharya Sunita
Published: April 2012

Although the lung expresses procoagulant proteins under inflammatory conditions, underlying mechanisms remain unclear. Here, we addressed lung endothelial expression of tissue factor (TF), which initiates the coagulation cascade and expression of which signifies development of a procoagulant phenotype in the vasculature. To establish the model of acid-induced acute lung injury (ALI), we intranasally instilled anesthetized mice with saline or acid. Then 2 h later, we isolated pulmonary vascular cells for flow cytometry and confocal microscopy to detect the leukocyte antigen, CD45 and the endothelial markers VE-cadherin and von Willebrand factor (vWf). Acid increased both the number of vWf-expressing cells as well as TF and P-selectin expressions on these cells. All of these effects were markedly inhibited by treating mice with antiplatelet serum, suggesting the involvement of platelets. The increased expressions of TF, vWf, and P-selectin in response to acid also occurred in platelets. Moreover, the effects were replicated in endothelial cells derived from isolated, blood-perfused lungs. However, the effect was inhibited completely in lungs perfused with platelet-depleted and, to a lesser extent, with leukocyte-depleted blood. Acid injury increased endothelial expressions of the platelet proteins, CD41 and CD42b, providing evidence that platelet proteins were transferred to the vascular surface. Reactive oxygen species (ROS) were implicated in these responses, in that the endothelial and platelet protein expressions were inhibited. We conclude that acid-induced ALI causes NOX2-mediated ROS generation that activates platelets, which then generate a procoagulant endothelial surface.