bluuebunny/crossref_metadata_2025 huggingface dataset:
Outer Membrane Protein AlkL Boosts Biocatalytic Oxyfunctionalization of Hydrophobic Substrates in Escherichia coli
Authors: Julsing Mattijs K. , Schrewe Manfred , Cornelissen Sjef , Hermann Inna , Schmid Andreas , Bühler Bruno
Published: June 2012

The outer membrane of microbial cells forms an effective barrier for hydrophobic compounds, potentially causing an uptake limitation for hydrophobic substrates. Low bioconversion activities (1.9 U gcdw−1) have been observed for the ω-oxyfunctionalization of dodecanoic acid methyl ester by recombinantEscherichia colicontaining the alkane monooxygenase AlkBGT ofPseudomonas putidaGPo1. Using fatty acid methyl ester oxygenation as the model reaction, this study investigated strategies to improve bacterial uptake of hydrophobic substrates. Admixture of surfactants and cosolvents to improve substrate solubilization did not result in increased oxygenation rates. Addition of EDTA increased the initial dodecanoic acid methyl ester oxygenation activity 2.8-fold. The use of recombinantPseudomonas fluorescensCHA0 instead ofE. coliresulted in a similar activity increase. However, substrate mass transfer into cells was still found to be limiting. Remarkably, the coexpression of thealkLgene ofP. putidaGPo1 encoding an outer membrane protein with so-far-unknown function increased the dodecanoic acid methyl ester oxygenation activity of recombinantE. coli28-fold. In a two-liquid-phase bioreactor setup, a 62-fold increase to a maximal activity of 87 U gcdw−1was achieved, enabling the accumulation of high titers of terminally oxyfunctionalized products. Coexpression ofalkLalso increased oxygenation activities toward the natural AlkBGT substrates octane and nonane, showing for the first time clear evidence for a prominent role of AlkL in alkane degradation. This study demonstrates that AlkL is an efficient tool to boost productivities of whole-cell biotransformations involving hydrophobic aliphatic substrates and thus has potential for broad applicability.
Stability and Infectivity of Cytolethal Distending Toxin Type V Gene-Carrying Bacteriophages in a Water Mesocosm and under Different Inactivation Conditions
Authors: Allué-Guardia Anna , Jofre Juan , Muniesa Maite
Published: June 2012

Two cytolethal distending toxin (Cdt) type V-encoding bacteriophages (Φ62 and Φ125) were induced spontaneously from their wild-type
Escherichia coli
strains and from the lysogens generated in
Shigella sonnei
. The stability of Cdt phages was determined at various temperatures and pH values after 1 month of storage by means of infectivity tests using a plaque blot assay and analysis of phage genomes using real-time quantitative PCR (qPCR): both were highly stable. We assessed the inactivation of Cdt phages by thermal treatment, chlorination, UV radiation, and in a mesocosm in both summer and winter. The results for the two Cdt phages showed similar trends and were also similar to the phage SOM23 used for reference, but they showed a much higher persistence than Cdt-producing
E. coli
. Cdt phages showed maximal inactivation after 1 h at 70°C, 30 min of UV radiation, and 30 min of contact with a 10-ppm chlorine treatment. Inactivation in a mesocosm was higher in summer than in winter, probably because of solar radiation. The treatments reduced the number of infectious phages but did not have a significant effect on the Cdt phage particles detected by qPCR. Cdt phages were quantified by qPCR in 73% of river samples, and these results suggest that Cdt phages are a genetic vehicle and the natural reservoir for
cdt
in the environment.
Synthesis, Release, and Recapture of Compatible Solute Proline by Osmotically Stressed Bacillus subtilis Cells
Authors: Hoffmann Tamara , von Blohn Carsten , Stanek Agnieszka , Moses Susanne , Barzantny Helena , Bremer Erhard
Published: June 2012

Bacillus subtilis
synthesizes large amounts of the compatible solute proline as a cellular defense against high osmolarity to ensure a physiologically appropriate level of hydration of the cytoplasm and turgor. It also imports proline for this purpose via the osmotically inducible OpuE transport system. Unexpectedly, an
opuE
mutant was at a strong growth disadvantage in high-salinity minimal media lacking proline. Appreciable amounts of proline were detected in the culture supernatant of the
opuE
mutant strain, and they rose concomitantly with increases in the external salinity. We found that the intracellular proline pool of severely salinity-stressed cells of the
opuE
mutant was considerably lower than that of its
opuE
+
parent strain. This loss of proline into the medium and the resulting decrease in the intracellular proline content provide a rational explanation for the observed salt-sensitive growth phenotype of cells lacking OpuE. None of the known MscL- and MscS-type mechanosensitive channels of
B. subtilis
participated in the release of proline under permanently imposed high-salinity growth conditions. The data reported here show that the OpuE transporter not only possesses the previously reported role for the scavenging of exogenously provided proline as an osmoprotectant but also functions as a physiologically highly important recapturing device for proline that is synthesized
de novo
and subsequently released by salt-stressed
B. subtilis
cells. The wider implications of our findings for the retention of compatible solutes by osmotically challenged microorganisms and the roles of uptake systems for compatible solutes are considered.
Two-Year Systematic Study To Assess Norovirus Contamination in Oysters from Commercial Harvesting Areas in the United Kingdom
Authors: Lowther James A. , Gustar Nicole E. , Powell Andrew L. , Hartnell Rachel E. , Lees David N.
Published: June 2012

The contamination of bivalve shellfish with norovirus from human fecal sources is recognized as an important human health risk. Standardized quantitative methods for the detection of norovirus in molluscan shellfish are now available, and viral standards are being considered in the European Union and internationally. This 2-year systematic study aimed to investigate the impact of the application of these methods to the monitoring of norovirus contamination in oyster production areas in the United Kingdom. Twenty-four monthly samples of oysters from 39 United Kingdom production areas, chosen to represent a range of potential contamination risk, were tested for norovirus genogroups I and II by using a quantitative real-time reverse transcription (RT)-PCR method. Norovirus was detected in 76.2% (643/844) of samples, with all sites returning at least one positive result. Both prevalences (presence or absence) and norovirus levels varied markedly between sites. However, overall, a marked winter seasonality of contamination by both prevalence and quantity was observed. Correlations were found between norovirus contamination and potential risk indicators, including harvesting area classifications,
Escherichia coli
scores, and environmental temperatures. A predictive risk score for norovirus contamination was developed by using a combination of these factors. In summary, this study, the largest of its type undertaken to date, provides a systematic analysis of norovirus contamination in commercial oyster production areas in the United Kingdom. The data should assist risk managers to develop control strategies to reduce the risk of human illness resulting from norovirus contamination of bivalve molluscs.
Association of a New Wolbachia Strain with, and Its Effects on, Leptopilina victoriae, a Virulent Wasp Parasitic to Drosophila spp
Authors: Gueguen Gwenaelle , Onemola Bodunde , Govind Shubha
Published: June 2012

Wolbachia
bacteria are ubiquitous intracellular bacteria of arthropods. Often considered reproductive parasites, they can benefit certain host species. We describe a new
Wolbachia
strain from
Leptopilina victoriae
, a
Drosophila
wasp. The strain is closely related to
Wolbachia
from
Culex
sp. Located to the posterior poles of oocytes, it manipulates its host's reproduction by inducing a male development type of cytoplasmic incompatibility. We also report its diverse effects on the wasp's life history traits.
Development and Application of an Arabinose-Inducible Expression System by Facilitating Inducer Uptake in Corynebacterium glutamicum
Authors: Zhang Yun , Shang Xiuling , Lai Shujuan , Zhang Guoqiang , Liang Yong , Wen Tingyi
Published: June 2012

Corynebacterium glutamicum
is currently used for the industrial production of a variety of biological materials. Many available inducible expression systems in this species use
lac
-derived promoters from
Escherichia coli
that exhibit much lower levels of inducible expression and leaky basal expression. We developed an arabinose-inducible expression system that contains the
l
-arabinose regulator AraC, the

P
BAD

promoter from the
araBAD
operon, and the
l
-arabinose transporter AraE, all of which are derived from
E. coli
. The level of inducible

P
BAD

-based expression could be modulated over a wide concentration range from 0.001 to 0.4%
l
-arabinose. This system tightly controlled the expression of the uracil phosphoribosyltransferase without leaky expression. When the gene encoding green fluorescent protein (GFP) was under the control of

P
BAD

promoter, flow cytometry analysis showed that GFP was expressed in a highly homogeneous profile throughout the cell population. In contrast to the case in
E. coli
,

P
BAD

induction was not significantly affected in the presence of different carbon sources in
C. glutamicum
, which makes it useful in fermentation applications. We used this system to regulate the expression of the
odhI
gene from
C. glutamicum
, which encodes an inhibitor of α-oxoglutarate dehydrogenase, resulting in high levels of glutamate production (up to 13.7 mM) under biotin nonlimiting conditions. This system provides an efficient tool available for molecular biology and metabolic engineering of
C. glutamicum
.
Two SusD-Like Proteins Encoded within a Polysaccharide Utilization Locus of an Uncultured Ruminant Bacteroidetes Phylotype Bind Strongly to Cellulose
Authors: Mackenzie A. K. , Pope P. B. , Pedersen H. L. , Gupta R. , Morrison M. , Willats W. G. T. , Eijsink V. G. H.
Published: June 2012

We demonstrate that two characteristic Sus-like proteins encoded within a polysaccharide utilization locus (PUL) bind strongly to cellulosic substrates and interact with plant primary cell walls. This shows associations between uncultured
Bacteroidetes
-affiliated lineages and cellulose in the rumen and thus presents new PUL-derived targets to pursue regarding plant biomass degradation.
Experimental Inoculation of Male Rats with Coxiella burnetii: Successful Infection but No Transmission to Cage Mates
Authors: Opsteegh Marieke , Hogerwerf Lenny , Nooijen Stephane , Dam-Deisz Cecile , de Heer Lianne , Reusken Chantal , Bouma Annemarie , Roest Hendrik-Jan , Nielen Mirjam , van der Giessen Joke
Published: June 2012

Beginning in 2007, the largest human Q fever outbreak ever described occurred in the Netherlands. Dairy goats from intensive farms were identified as the source, amplifying
Coxiella burnetii
during gestation and shedding large quantities during abortions. It has been postulated that wild rodents are reservoir hosts from which
C. burnetii
can be transmitted to domestic animals and humans. However, little is known about the infection dynamics of
C. burnetii
in wild rodents. The aim of this study was to investigate whether brown rats (
Rattus norvegicus
) can be experimentally infected with
C. burnetii
and whether transmission to a cage mates occurs. Fourteen male brown rats (wild type) were intratracheally or intranasally inoculated with a Dutch
C. burnetii
isolate obtained from a goat. At 3 days postinoculation, a contact rat was placed with each inoculated rat. The pairs were monitored using blood samples and rectal and throat swabs for 8 weeks, and after euthanasia the spleens were collected. Rats became infected by both inoculation routes, and detection of
C. burnetii
DNA in swabs suggests that excretion occurred. However, based on the negative spleens in PCR and the lack of seroconversion, none of the contact animals was considered infected; thus, no transmission was observed. The reproduction ratio
R
0
was estimated to be 0 (95% confidence interval = 0 to 0.6), indicating that it is unlikely that rats act as reservoir host of
C. burnetii
through sustained transmission between male rats. Future research should focus on other transmission routes, such as vertical transmission or bacterial shedding during parturition.
Capturing Greater 16S rRNA Gene Sequence Diversity within the Domain Bacteria
Authors: Winsley T. , van Dorst J. M. , Brown M. V. , Ferrari B. C.
Published: June 2012

A large proportion of “universal” 16S PCR primers lack sequence homology to many of the “candidate” divisions, severely limiting bacterial diversity assessments. We designed a primer set that offers a 50% increase
in silico
in coverage of the domain
Bacteria
over the commonly used primer combination 27F/519R. Comparisons using pyrosequencing on soil environments showed a significant increase in recovery of taxonomic diversity with around a 3-fold increase in recovery of sequences from candidate divisions.
Antifungal Activity of Bacillus amyloliquefaciens NJN-6 Volatile Compounds against Fusarium oxysporum f. sp. cubense
Authors: Yuan Jun , Raza Waseem , Shen Qirong , Huang Qiwei
Published: June 2012

Bacillus amyloliquefaciens
NJN-6 produces volatile compounds (VOCs) that inhibit the growth and spore germination of
Fusarium oxysporum
f. sp.
cubense
. Among the total of 36 volatile compounds detected, 11 compounds completely inhibited fungal growth. The antifungal activity of these compounds suggested that VOCs can play important roles over short and long distances in the suppression of
Fusarium oxysporum
.
Phenylacetic Acid Catabolism and Its Transcriptional Regulation in Corynebacterium glutamicum
Authors: Chen Xi , Kohl Thomas A. , Rückert Christian , Rodionov Dmitry A. , Li Ling-Hao , Ding Jiu-Yuan , Kalinowski Jörn , Liu Shuang-Jiang
Published: June 2012

The industrially important organism
Corynebacterium glutamicum
has been characterized in recent years for its robust ability to assimilate aromatic compounds. In this study,
C. glutamicum
strain AS 1.542 was investigated for its ability to catabolize phenylacetic acid (PAA). The
paa
genes were identified; they are organized as a continuous
paa
gene cluster. The type strain of
C. glutamicum
, ATCC 13032, is not able to catabolize PAA, but the recombinant strain ATCC 13032/pEC-K18
mob
2::
paa
gained the ability to grow on PAA. The
paaR
gene, encoding a TetR family transcription regulator, was studied in detail. Disruption of
paaR
in strain AS 1.542 resulted in transcriptional increases of all
paa
genes. Transcription start sites and putative promoter regions were determined. An imperfect palindromic motif (5′-ACTNACCGNNCGNNCGGTNAGT-3′; 22 bp) was identified in the upstream regions of
paa
genes. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of PaaR to this motif, and phenylacetyl coenzyme A (PA-CoA) blocked binding. It was concluded that PaaR is the negative regulator of PAA degradation and that PA-CoA is the PaaR effector. In addition, GlxR binding sites were found, and binding to GlxR was confirmed. Therefore, PAA catabolism in
C. glutamicum
is regulated by the pathway-specific repressor PaaR, and also likely by the global transcription regulator GlxR. By comparative genomic analysis, we reconstructed orthologous PaaR regulons in 57 species, including species of
Actinobacteria
,
Proteobacteria
, and
Flavobacteria
, that carry PAA utilization genes and operate by conserved binding motifs, suggesting that PaaR-like regulation might commonly exist in these bacteria.
Application of
pheB
as a Reporter Gene for Geobacillus spp., Enabling Qualitative Colony Screening and Quantitative Analysis of Promoter Strength
Authors: Bartosiak-Jentys Jeremy , Eley Kirstin , Leak David J.
Published: June 2012

The
pheB
gene from
Geobacillus stearothermophilus
DSM6285 has been exploited as a reporter gene for
Geobacillus
spp. The gene product, catechol 2,3-dioxygenase (C23O), catalyzes the formation of 2-hydroxymuconic semialdehyde, which can be readily assayed. The reporter was used to examine expression from the
ldh
promoter associated with fermentative metabolism.
Effect of
iacP
Mutation on Flagellar Phase Variation in Salmonella enterica Serovar Typhimurium Strain UK-1
Authors: Eom Jeong Seon , Kim Jin Seok , Jang Jung Im , Kim Hyeon Guk , Bang Iel-Soo , Park Yong Keun
Published: June 2012

Flagella are surface appendages that are important for bacterial motility and invasion of host cells. Two flagellin subunits in
Salmonella enterica
serovar Typhimurium, FliC and FljB, are alternatively expressed by a site-specific DNA inversion mechanism called flagellar phase variation. Although this inversion mechanism is understood at the molecular level, the key factor controlling the expression of the two flagellin subunits has not been determined. In this study, we found that a putative acyl carrier protein, IacP, affects flagellar phase variation in
S.
Typhimurium strain UK-1 under
Salmonella
pathogenicity island 1 (SPI1)-inducing conditions. Liquid chromatography-mass spectrometry analysis of the secreted proteins from
S.
Typhimurium determined that the amount of FljB secreted was significantly higher in the
iacP
mutant strain, a finding confirmed by Western blot analysis. Northern blotting, quantitative PCR, and microarray data showed that the level of FljB in the
iacP
mutant strain was regulated at the transcriptional level, although the transcription and expression of the
fliC
gene were independent of IacP. FljB production was abolished by the deletion of the Hin DNA invertase but could be restored by the introduction of a plasmid carrying the
hin
gene. We also found that in the
iacP
mutant strain, the orientation of the invertible H segment is in the FljB-expressing phase. Furthermore, electron microscopy observations indicated that the
iacP
mutant strain had more flagella per cell than the wild-type strain. These results suggest that IacP is associated with flagellar phase switching under SPI1-inducing conditions.
First Insights into the Unexplored Two-Component System YehU/YehT in Escherichia coli
Authors: Kraxenberger Tobias , Fried Luitpold , Behr Stefan , Jung Kirsten
Published: June 2012

Two-component systems (TCSs) consisting of a membrane-anchored histidine kinase (HK) and a response regulator (RR) with DNA-binding activity. are major players in signal transduction in prokaryotes. Whereas most TCSs in
Escherichia coli
are well characterized, almost nothing is known about the LytS-like HK YehU and the corresponding LytTR-like RR YehT. To identify YehT-regulated genes, we compared the transcriptomes of
E. coli
cells overproducing either YehT or the RR KdpE (control). The expression levels of 32 genes differed more than 8-fold between the two strains. A comprehensive evaluation of these genes identified
yjiY
as a target of YehT. Electrophoretic mobility shift assays with purified YehT confirmed that YehT interacts directly with the
yjiY
promoter. Specifically, YehT binds to two direct repeats of the motif ACC(G/A)CT(C/T)A separated by a 13-bp spacer in the
yjiY
promoter. The target gene
yjiY
encodes an inner membrane protein belonging to the CstA superfamily of transporters. In
E. coli
cells growing in media containing peptides or amino acids as a carbon source,
yjiY
is strongly induced at the onset of the stationary-growth phase. Moreover, expression was found to be dependent on cyclic AMP (cAMP)/cAMP receptor protein (CRP). It is suggested that YehU/YehT participates in the stationary-phase control network.
Transcription of the
oprF
Gene of Pseudomonas aeruginosa Is Dependent Mainly on the SigX Sigma Factor and Is Sucrose Induced
Authors: Bouffartigues Emeline , Gicquel Gwendoline , Bazire Alexis , Bains Manjeet , Maillot Olivier , Vieillard Julien , Feuilloley Marc G. J. , Orange Nicole , Hancock R. E. W. , Dufour Alain , Chevalier Sylvie
Published: June 2012

The OprF porin is the major outer membrane protein of
Pseudomonas aeruginosa
. OprF is involved in several crucial functions, including cell structure, outer membrane permeability, environmental sensing, and virulence. The
oprF
gene is preceded by the
sigX
gene, which encodes the poorly studied extracytoplasmic function (ECF) sigma factor SigX. Three
oprF
promoters were previously identified. Two intertwined promoters dependent on σ
70
and SigX are located in the
sigX
-
oprF
intergenic region, whereas a promoter dependent on the ECF AlgU lies within the
sigX
gene. An additional promoter was found in the
cmpX
-
sigX
intergenic region. In this study, we dissected the contribution of each promoter region and of each sigma factor to
oprF
transcription using transcriptional fusions. In Luria-Bertani (LB) medium, the
oprF
-proximal region (
sigX
-
oprF
intergenic region) accounted for about 80% of the
oprF
transcription, whereas the AlgU-dependent promoter had marginal activity. Using the
sigX
mutant PAOSX, we observed that the SigX-dependent promoter was largely predominant over the σ
70
-dependent promoter.
oprF
transcription was increased in response to low NaCl or high sucrose concentrations, and this induced transcription was strongly impaired in the absence of SigX. The lack of OprF itself increased
oprF
transcription. Since these conditions led to cell wall alterations,
oprF
transcription could be activated by signals triggered by perturbation of the cell envelope.
Rot and SaeRS Cooperate To Activate Expression of the Staphylococcal Superantigen-Like Exoproteins
Authors: Benson Meredith A. , Lilo Sarit , Nygaard Tyler , Voyich Jovanka M. , Torres Victor J.
Published: June 2012

Staphylococcus aureus
is a significant human pathogen that is capable of infecting a wide range of host tissues. This bacterium is able to evade the host immune response by utilizing a repertoire of virulence factors. These factors are tightly regulated by various two-component systems (TCS) and transcription factors. Previous studies have suggested that transcriptional regulation of a subset of immunomodulators, known as the staphylococcal superantigen-like proteins (Ssls), is mediated by the master regulators accessory gene regulator (Agr) TCS,
S. aureus
exoprotein expression (Sae) TCS, and Rot. Here we demonstrate that Rot and SaeR, the response regulator of the Sae TCS, synergize to coordinate the activation of the
ssl
promoters. We have determined that both transcription factors are required, but that neither is sufficient, for promoter activation. This regulatory scheme is mediated by direct binding of both transcription factors to the
ssl
promoters. We also demonstrate that clinically relevant methicillin-resistant
S. aureus
(MRSA) strains respond to neutrophils via the Sae TCS to upregulate the expression of
ssl
s. Until now, Rot and the Sae TCS have been proposed to work in opposition of one another on their target genes. This is the first example of these two regulators working in concert to activate promoters.
Cysteine Catabolism and Cysteine Desulfhydrase (CdsH/STM0458) in Salmonella enterica Serovar Typhimurium
Authors: Oguri Tamiko , Schneider Barbara , Reitzer Larry
Published: June 2012

Cysteine is potentially toxic and can affect diverse functions such as oxidative stress, antibiotic resistance, and swarming motility. The contribution of cysteine catabolism in modulating responses to cysteine has not been examined, in part because the genes have not been identified and mutants lacking these genes have not been isolated or characterized. We identified the gene for a previously described cysteine desulfhydrase, which we designated
cdsH
(formerly STM0458). We also identified a divergently transcribed gene that regulates
cdsH
expression, which we designated
cutR
(formerly
ybaO
, or STM0459). CdsH appears to be the major cysteine-degrading and sulfide-producing enzyme aerobically but not anaerobically. Mutants with deletions of
cdsH
and
ybaO
exhibited increased sensitivity to cysteine toxicity and altered swarming motility but unaltered cysteine-enhanced antibiotic resistance and survival in macrophages.
Increased Production of the Exopolysaccharide Succinoglycan Enhances Sinorhizobium meliloti 1021 Symbiosis with the Host Plant Medicago truncatula
Authors: Jones Kathryn M.
Published: June 2012

The nitrogen-fixing rhizobial symbiont
Sinorhizobium meliloti
1021 produces acidic symbiotic exopolysaccharides that enable it to initiate and maintain infection thread formation on host legume plants. The exopolysaccharide that is most efficient in mediating this process is succinoglycan (exopolysaccharide I [EPSI]), a polysaccharide composed of octasaccharide repeating units of 1 galactose and 7 glucose residues, modified with succinyl, acetyl, and pyruvyl substituents. Previous studies had shown that
S. meliloti
1021 mutants that produce increased levels of succinoglycan, such as
exoR
mutants, are defective in symbiosis with host plants, leading to the hypothesis that high levels of succinoglycan production might be detrimental to symbiotic development. This study demonstrates that increased succinoglycan production itself is not detrimental to symbiotic development and, in fact, enhances the symbiotic productivity of
S. meliloti
1021 with the host plant
Medicago truncatula
cv. Jemalong A17. Increased succinoglycan production was engineered by overexpression of the
exoY
gene, which encodes the enzyme responsible for the first step in succinoglycan biosynthesis. These results suggest that the level of symbiotic exopolysaccharide produced by a rhizobial species is one of the factors involved in optimizing the interaction with plant hosts.
Rhamnosyltransferase Genes
migA
and
wapR
Are Regulated in a Differential Manner To Modulate the Quantities of Core Oligosaccharide Glycoforms Produced by Pseudomonas aeruginosa
Authors: Kocíncová Dana , Ostler Sarah L. , Anderson Erin M. , Lam Joseph S.
Published: June 2012

migA
and
wapR
are rhamnosyltransferase genes involved in the biosynthesis of
Pseudomonas aeruginosa
lipopolysaccharide core oligosaccharide. Here, we show that preferential expression of
migA
and
wapR
correlated with the levels of uncapped and O polysaccharide-capped core, respectively.
wapR
is negatively regulated, while
migA
is positively regulated by RhlR/RhlI quorum sensing.
Risk of cancer in patients using glucose-lowering agents: a nationwide cohort study of 3.6 million people
Authors: Andersson Charlotte , Vaag Allan , Selmer Christian , Schmiegelow Michelle , Sørensen Rikke , Lindhardsen Jesper , Gislason Gunnar H , Køber Lars , Torp-Pedersen Christian
Published: June 2012

Objectives

To study the association between exposures to glucose-lowering therapy and risk of cancer using the nationwide administrative registers in Denmark.

Design

Nationwide cohort study.

Setting

All hospitals in Denmark.

Participants

All individuals aged ≥35 years in 1998–2009 who were naive to glucose-lowering treatment and had no history of cancer. Primary measures outcomes: first cancer diagnosis between 1998 and 2009. The RR of cancer as dependent on exposure to individual glucose-lowering agents was assessed by multivariable Poisson regression models.

Results

Of 159 894 patients that initiated treatment with glucose-lowering agents, 12 789 developed cancer, incidence rate 17.4/1000 person-years. Of the remaining 3 447 904 individuals not using glucose-lowering agents, 293 878 developed cancer, incidence rate 7.9/1000 person-years. Use of different types of glucose-lowering agents including human insulin, insulin analogues, as well as sulfonylureas were associated with a quantitatively similar and significantly increased RR of cancer of 1.2–1.3 compared with unexposed individuals after multivariable adjustment. For the majority of agents, the authors identified the highest RR of cancer during the first 30 treatment days with a subsequent decline of risk approaching the cancer risk of the background population only 6–12 months after initiation of treatments.

Conclusions

Use of most glucose-lowering agents including sulfonylureas was associated with a comparable increased risk of cancer shortly after initiation of treatment and subsequently a decline to the risk of the background population. This suggests that the relation is not causal.
Ambient temperature and spontaneous intracerebral haemorrhage: a cross-sectional analysis in Tainan, Taiwan
Authors: Fang Chen-Wen , Ma Mi-Chia , Lin Huey-Juan , Chen Chih-Hung
Published: June 2012

Objectives

Ambient temperature has been reported to play a role in the occurrence of spontaneous intracerebral haemorrhage (ICH). This study aimed to investigate the relation between ambient temperature of onset time and ICH and the effect of hourly temperature within 72 h before ICH.

Design

This is a cross-sectional case-only study and a retrospective analysis of a prospective database.

Setting

Two medical centres in Southern Taiwan participating a prospective stroke registry.

Participants

A total of 933 patients with ICH registered from August 2006 to July 2008.

Primary and secondary outcome measures

The hourly temperature was collected, and patients were grouped according to the deciles of hourly temperature at onset. Primary outcome was the association between the number of ICH cases and mean temperature (or temperature variation). Secondary outcome was the difference of onset temperature and hourly temperature before onset in patients with known onset time.

Results

Winter (n=282) had significant higher ICH cases than other seasons (n=651; p=0.002). Of those patients with an exact time of onset, the results showed 13% patients occurred at the lowest decile temperature group (<17.4°C) and 8% patients occurred at the highest decile temperature group (>30.8°C). It showed a significant temperature change before onset for these patients (p<0.005).

Conclusions

This study showed that lower ambient temperature and variation of temperatures precipitated ICH in southern Taiwan. Better protecting vulnerable people from cold temperatures may prevent the occurrences of ICH.
Smoking and suicidal behaviours in a sample of US adults with low mood: a retrospective analysis of longitudinal data
Authors: Covey Lirio S , Berlin Ivan , Hu Mei-Chen , Hakes Jahn K
Published: June 2012

Objective

To investigate whether: (1) smoking predicts suicide-related outcomes (SROs), (2) prior SRO predicts smoking, (3) smoking abstinence affects the risk of SRO and (4) psychiatric comorbidity modifies the relationship between smoking and SRO.

Design

Retrospective analysis of longitudinal data obtained in wave 1 (2001–2002) and wave 2 (2004–2005) of the National Epidemiologic Survey on Alcohol and Related Conditions.

Setting

Face-to-face interviews conducted with persons in the community.

Participants

US adults (N=43 093) aged 18 years or older were interviewed in wave 1 and reinterviewed (N=34 653) 3 years later. For the present study, the sample was the subset of persons (N=7352) who at the wave 2 interview reported low mood lasting 2 weeks or more during the past 3 years and were further queried regarding SRO occurring between waves 1 and 2.

Outcome measures

SRO composed of any of the following: (1) want to die, (2) suicidal ideation, (3) suicide attempt, reported at wave 2. Current smoking reported at wave 2.

Results

Current and former smoking in wave 1 predicted increased risk for wave 2 SRO independently of prior SRO, psychiatric history and socio-demographic characteristics measured in wave 1 (adjusted OR (AOR)=1.41, 95% CI 1.28 to 1.55 for current smoking; AOR=1.32, 95% CI 1.21 to 1.43 for former smoking). Prior SRO did not predict current smoking in wave 2. Compared with persistent never-smokers, risk for future SRO was highest among relapsers (AOR=3.42, 95% CI 2.85 to 4.11), next highest among smoking beginners at wave 2 (AOR=1.82, 95% CI 1.51 to 2.19) and lowest among long-term (4+ years) former smokers (AOR=1.22, 95% CI 1.12 to 1.34). Compared with persistent current smokers, risk for SRO was lower among long-term abstainers (p<0.0001) but not among shorter-term abstainers (p=0.26).

Conclusions

Smoking increased the risk of future SRO independently of psychiatric comorbidity. Abstinence of several years duration reduced that risk.
Protocol for a population-based study of rheumatic heart disease prevalence and cardiovascular outcomes among schoolchildren in Nepal
Authors: Pilgrim Thomas , Kalesan Bindu , Karki Prahlad , Basnet Anil , Meier Bernhard , Urban Philip , Shrestha Nikesh Raj
Published: June 2012

Introduction

Rheumatic heart disease (RHD) remains a major contributor to morbidity and mortality in developing countries. The reported prevalence rates of RHD are highly variable and mainly attributable to differences in the sensitivity of either clinical screening to detect advanced heart disease or echocardiographic evaluation where disease is diagnosed earlier across a continuous spectrum. The clinical significance of diagnosis of subclinical RHD by echocardiographic screening and early implementation of secondary prevention has not been clearly established.

Methods and analysis

The authors designed a cross-sectional survey to determine the prevalence of RHD in children from private and public schools between the age of 5 and 15 years in urban and rural areas of Eastern Nepal using both cardiac auscultation and echocardiographic evaluation. Children with RHD will be treated with secondary prevention and enrolled in a prospective cohort study. The authors will compare the prevalence rates by cardiac auscultation and echocardiography, determine risk factors associated with diagnosis and progression of RHD, investigate social and economic barriers for receiving adequate cardiac care and assess clinical outcomes with regular medical surveillance as a function of stage of disease at the time of diagnosis. Prospective clinical studies investigating the impact of secondary prevention for subclinical RHD on long-term clinical outcome will be of central relevance for future health resource utilisation in developing countries.

Ethics and dissemination

The study was considered ethically uncritical and was given an exempt status by the ethics committee at University of Bern, Switzerland. The study has been submitted to the National Nepal Health Research Council and was registered withhttp://www.ClinicalTrials.gov(NCT01550068). The study findings will be reported in peer-reviewed publications.

ClinicalTrials.gov Identifier

NCT01550068.
Should we test for tetanus immunity in all emergency department patients with wounds?
Authors: McVicar Jane
Published: June 2012

Background

People who present to the emergency department often do not know their tetanus immunisation status. The Protetanus test can determine whether a person is immune and can guide treatment decisions.

Objectives

To examine whether testing all patients for immunity is clinically advisable and cost-effective.

Methods

200 patients presenting to the emergency department with wounds were asked whether they were covered for tetanus, not covered or did not know. All had their tetanus immunity tested with the Protetanus kit and the result was compared with reported status. The number of unnecessary vaccinations which might have been given based on recall was calculated. The cost of testing and subsequent treatment versus vaccinations based on recall was calculated.

Results

136 (68%) tested positive for tetanus immunity; 64 (32%) were negative. Age, sex and nationality were not associated with tetanus immunity. 151 (75.5%) did not know their status. Of these, 101 (66.9%) were positive and 50 (33.1%) negative. 49 (24.5%) were sure of their status. 36 said they were covered of whom 10 (27.8%) were wrong. 13 said they were not covered of whom 9 (69.2%) were wrong. If vaccination were based on recall status 38.8% of patients would receive incorrect treatment. Testing all 200 and treating appropriately would save £984, or £4.92 per patient compared with vaccination based on recall.

Conclusion

On clinical grounds testing is advisable and it may produce significant cost savings.
Bedside ultrasound and the assessment of renal colic: a review
Authors: Dalziel Peregrine James , Noble Vicki Elizabeth
Published: June 2012

Renal colic is a common emergency department (ED) presentation. The use of CT in the diagnosis of renal colic has increased over the past two decades and is now the most common imaging modality used in many institutions. However, with growing concerns about cumulative radiation exposure, increasing healthcare costs and patient flow in EDs, alternative approaches may need to be considered. Point-of-care ultrasound may offer a radiation-free, rapid and cost-effective alternative. The authors reviewed the literature and synthesised some of the data comparing point-of-care ultrasound with CT scanning as well as some of the evidence for how it might be incorporated into a renal colic management strategy. It is concluded that there is enough evidence to define a rational algorithm for renal colic management. A prospectively validated algorithm would greatly assist primary care and emergency practitioners while reducing costs and radiation dose.
Immunophenotypic heterogeneity of normal plasma cells: comparison with minimal residual plasma cell myeloma
Authors: Liu Dingsheng , Lin Pei , Hu Ying , Zhou Yi , Tang Guilin , Powers Linda , Medeiros L Jeffrey , Jorgensen Jeffrey L , Wang Sa A
Published: June 2012

Plasma cell myeloma (PCM) exhibits immunophenotypic aberrancies that can be used for minimal residual disease (MRD) detection after therapy. The authors sought to determine whether non-neoplastic plasma cells, especially in the bone marrow (BM) post various therapies, would exhibit immunophenotypic variations interfering PCM MRD detection. The authors studied the flow cytometric immunophenotypes of non-neoplastic plasma cells from 50 BM specimens, including 12 untreated BM and 38 BM specimens from patients with non-plasmacytic haematological malignancies undergoing various therapies, and compared with 59 BM specimens positive for PCM MRD. Non-neoplastic plasma cells showed heterogeneous expressions of CD45 (78% (41–100)) and CD19 (80% (52–97)), and were negative for CD20 and CD117. CD56 was observed in a small subset (6% (0–37)) and CD28 in a larger subset (15% (0–59)) of non-neoplastic plasma cells, with the latter more frequently expressed in post-treatment BMs (p=0.01). However, despite a partial immunophenotypic overlap, PCM cells could be reliably discriminated from non-neoplastic plasma cells by the presence of a higher number of aberrancies (3 (1–6) vs 0 (0–2)) and stronger intensity and uniformity of aberrant expression (p<0.001 in each marker using a cut-off value). In addition, simultaneous assessment of cytoplasmic κ/λ with surface markers detected light chain restriction in all 59 PCM cases. In conclusion, non-neoplastic plasma cells in BM are more immunophenotypically heterogeneous than previously understood; however, these immunophenotypic variations differ from those of PCM. With advances in multicolour flow cytometry and application of recently validated markers, PCM MRD may still be reliably distinguished from non-neoplastic plasma cells.
Income inequalities in case death of ischaemic heart disease in the Netherlands: a national record-linked study
Authors: Stirbu Irina , Looman Caspar , Nijhof Geesje J , Reulings Petra G , Mackenbach Johan P
Published: June 2012

Background

Socioeconomic inequalities in ischaemic heart disease (IHD) mortality have been found in most European countries, but it is unclear to what extent inequalities in survival, as opposed to incidence, contribute to these inequalities in mortality. The author studied income-related inequalities in short-term and long-term case death after first hospitalisation with acute myocardial infarction (AMI) and chronic ischaemic heart disease (CIHD), as well as inequalities in cardiovascular surgical procedures among patients admitted with IHD, in the Netherlands.

Methods

Design: A nationwide prospective cohort study of patients first admitted for IHD. Data: Obtained by record linkage at individual level of national hospital discharge, cause of death, population and income registries. Patients: 15 416 patients admitted to a hospital with first episode of AMI and 31 209 patients admitted to a hospital with first episode of CIHD in the period 2003–2005. Main outcome measures: Differences by income quintile in short-term (28 days) and long-term (1 year) case death after first hospital admission with AMI and CIHD. Differences by income quintile in Percutaneous Transluminal Coronary Angioplasty (PTCA) and Coronary Artery Bypass Graft operations among patients with first admission for AMI.

Results

After adjustment for age, ethnicity and comorbidity, men and women in the lower income quintiles had a higher 28-day and 1-year case death after first hospitalisation with an AMI or CIHD. After adjustment for age and comorbidity, patients admitted to the hospital with a first AMI also had a lower probability of undergoing a PTCA procedure if they belonged to a lower income quintile. There were large between-hospital variations in inequalities in 28-day mortality for patients admitted with a first AMI.

Conclusions

Higher mortality from IHD among lower income people is likely to be partly due to higher case death after first hospital admission. Inequalities in utilisation of PTCA and between-hospital variations in inequalities in outcomes suggest that inequalities in access to good quality care may play a role in explaining the higher case death of IHD among people with lower socioeconomic position. Further research is needed to elucidate the causes of these inequalities in case death.
Insights into the timing of repeated testing after treatment forChlamydia trachomatis: data and modelling study
Authors: Heijne Janneke Cornelia Maria , Herzog Sereina Annik , Althaus Christian Lorenz , Tao Guoyu , Kent Charlotte Kathleen , Low Nicola
Published: June 2012

Objectives

The objective of this study was to determine the optimal time interval for a repeatedChlamydia trachomatis(chlamydia) test.

Methods

The authors used claims data for US women aged 15–25 years who were enrolled in commercial health insurance plans in the MarketScan database between 2002 and 2006. The authors determined the numbers of initial positive and negative tests that were followed by a repeated test and the positivity of repeated tests. The authors used a dynamic transmission pair model that reflects the partnership formation and separation processes in 15–25 year olds to determine the time course of repeated infections in women under different levels of notifying the current partner. The authors then explored the additional impact of repeated testing uptake on reducing chlamydia prevalence.

Results

40% (4949/12 413) of positive tests were followed by a repeated test compared with 22% (89 119/402 659) of negative tests at any time. Positivity of repeated tests followed by an initial positive test was high: 15% (736) after a positive test versus 3% (2886) after a negative test. The transmission model showed a peak in repeated infections between 2 and 5 months after treatment. For a chlamydia testing uptake of 10% per year, the additional impact of repeated testing on reducing chlamydia population prevalence was modest.

Conclusions

The mathematical model predictions support the recommended interval for repeat chlamydia testing. This study provides information that can be used to design randomised controlled trials to determine more effective interventions to prevent chlamydial reinfection.
Cross-sectional study on the prevalence of HPV antibodies in the general population of the Czech Republic
Authors: Hamsikova Eva , Ludvikova Viera , Stasikova Jana , Tachezy Ruth
Published: June 2012

Objectives

The assessment of the prevalence of antibodies to human papillomaviruses (HPV) in the healthy population is essential for effective planning of HPV vaccine implementation into the preventive programmes for HPV-associated diseases and for the prospective monitoring of the impact of HPV vaccines in the Czech population.

Methods

The seropositivity for HPV-6, 11, 16, 18, 31 and 33 virus-like particles was determined in sera from 3150 healthy individuals (age range 6–76 years) by means of enzyme-linked immunoassay.

Results

The seroprevalences for HPV-6, 11, 16, 18, 31 and 33 were 23.8%, 15.2%, 14.5%, 9.9%, 16.4% and 9.6% in women and 18.4%, 13.7%, 6.5%, 5.4%, 6.1% and 4.3% in men. For both genders, except for HPV11, these rates were age dependent. The prevalence of antibodies to HPV-16 and/or 18 reached the maximum of 27.0% in women 30–39 years of age and of 14.4% in men 50–59 years of age. The highest proportion of individuals' seropositive for any of the vaccine types HPV-6/11/16/18 was in 30- to 39-year-old women (50.0%) and in ≥60-year-old men (37.6%). Antibodies specific for vaccine HPV types were detected in 18.0% of children 6- to 14-year-old but in 26.4%, those older than 14 years.

Conclusions

The data reveal age-specific differences in the HPV seropositivity rates between healthy women and men and support the implementation of HPV vaccination in the Czech Republic before the age of 13.
The cytokines interleukin-1β and tumor necrosis factor-α stimulate CFTR-mediated fluid secretion by swine airway submucosal glands
Authors: Baniak Nicholas , Luan Xiaojie , Grunow Amber , Machen Terry E. , Ianowski Juan P.
Published: June 2012

The airway is kept sterile by an efficient innate defense mechanism. The cornerstone of airway defense is mucus containing diverse antimicrobial factors that kill or inactivate pathogens. Most of the mucus in the upper airways is secreted by airway submucosal glands. In patients with cystic fibrosis (CF), airway defense fails and the lungs are colonized by bacteria, usually Pseudomonas aeruginosa . Accumulating evidence suggests that airway submucosal glands contribute to CF pathogenesis by failing to respond appropriately to inhalation of bacteria. However, the regulation of submucosal glands by the innate immune system remains poorly understood. We studied the response of submucosal glands to the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α. These are released into the airway submucosa in response to infection with the bacterium P. aeruginosa and are elevated in CF airways. Stimulation with IL-1β and TNF-α increased submucosal gland secretion in a concentration-dependent manner with a maximal secretion rate of 240 ± 20 and 190 ± 40 pl/min, respectively. The half maximal effective concentrations were 11 and 20 ng/ml, respectively. The cytokine effect was dependent on cAMP but was independent of cGMP, nitric oxide, Ca2+, or p38 MAP kinase. Most importantly, IL-1β- and TNF-α-stimulated secretion was blocked by the CF transmembrane conductance regulator (CFTR) blocker, CFTRinh172 (100 μmol/l) but was not affected by the Ca2+-activated Cl−channel blocker, niflumic acid (1 μmol/l). The data suggest, that during bacterial infections and resulting release of proinflammatory cytokines, the glands are stimulated to secrete fluid, and this response is mediated by cAMP-activated CFTR, a process that would fail in patients with CF.