bluuebunny/crossref_metadata_2025 huggingface dataset:
Guanidination of Soluble Lysine-Rich Cyanophycin Yields a Homoarginine-Containing Polyamide
Authors: Frommeyer Maja , Bergander Klaus , Steinbüchel Alexander
Published: February 2014

Soluble cyanobacterial granule polypeptide (CGP), especially that isolated from recombinant
Escherichia coli
strains, consists of aspartic acid, arginine, and a greater amount of lysine than that in insoluble CGP isolated from cyanobacteria or various other recombinant bacteria.
In vitro
guanidination of lysine side chains of soluble CGP with
o
-methylisourea (OMIU) yielded the nonproteinogenic amino acid homoarginine. The modified soluble CGP consisted of 51 mol% aspartate, 14 mol% arginine, and 35 mol% homoarginine. The complete conversion of lysine residues to homoarginine was confirmed by (i) nuclear magnetic resonance spectrometry, (ii) coupled liquid chromatography-mass spectrometry, and (iii) high-performance liquid chromatography. Unlike soluble CGP, this new homoarginine-containing polyamide was soluble only under acidic or alkaline conditions and was insoluble in water or at a neutral pH. Thus, it showed solubility behavior similar to that of the natural insoluble polymer isolated from cyanobacteria, consisting of aspartic acid and arginine only. Polyacrylamide gel electrophoresis revealed similar degrees of polymerization of the native (12- to 40-kDa) and modified (10- to 35-kDa) polymers. This study showed that the chemical structure and properties of a biopolymer could be changed by
in vitro
introduction of a new functional group after biosynthesis of the native polymer. In addition, the modified CGP could be digested
in vitro
using the cyanophycinase from
Pseudomonas alcaligenes
strain DIP1, yielding a new dipeptide consisting of aspartate and homoarginine.
ExpR Coordinates the Expression of Symbiotically Important, Bundle-Forming Flp Pili with Quorum Sensing in Sinorhizobium meliloti
Authors: Zatakia Hardik M. , Nelson Cassandra E. , Syed Umair J. , Scharf Birgit E.
Published: February 2014

Type IVb pili in enteropathogenic bacteria function as a host colonization factor by mediating tight adherence to host cells, but their role in bacterium-plant symbiosis is currently unknown. The genome of the symbiotic soil bacterium
Sinorhizobium meliloti
contains two clusters encoding proteins for type IVb pili of the Flp (fimbrial low-molecular-weight protein) subfamily. To establish the role of Flp pili in the symbiotic interaction of
S. meliloti
and its host,
Medicago sativa
, we deleted
pilA1
, which encodes the putative pilin subunit in the chromosomal
flp-1
cluster and conducted competitive nodulation assays. The
pilA1
deletion strain formed 27% fewer nodules than the wild type. Transmission electron microscopy revealed the presence of bundle-forming pili protruding from the polar and lateral region of
S. meliloti
wild-type cells. The putative pilus assembly ATPase CpaE1 fused to mCherry showed a predominantly unilateral localization. Transcriptional reporter gene assays demonstrated that expression of
pilA1
peaks in early stationary phase and is repressed by the quorum-sensing regulator ExpR, which also controls production of exopolysaccharides and motility. Binding of acyl homoserine lactone-activated ExpR to the
pilA1
promoter was confirmed with electrophoretic mobility shift assays. A 17-bp consensus sequence for ExpR binding was identified within the 28-bp protected region by DNase I footprinting analyses. Our results show that Flp pili are important for efficient symbiosis of
S. meliloti
with its plant host. The temporal inverse regulation of exopolysaccharides and pili by ExpR enables
S. meliloti
to achieve a coordinated expression of cellular processes during early stages of host interaction.
Autotrophic Carbon Dioxide Fixation via the Calvin-Benson-Bassham Cycle by the Denitrifying Methanotroph “Candidatus Methylomirabilis oxyfera”
Authors: Rasigraf Olivia , Kool Dorien M. , Jetten Mike S. M. , Sinninghe Damsté Jaap S. , Ettwig Katharina F.
Published: February 2014

Methane is an important greenhouse gas and the most abundant hydrocarbon in the Earth's atmosphere. Methanotrophic microorganisms can use methane as their sole energy source and play a crucial role in the mitigation of methane emissions in the environment. “
Candidatus
Methylomirabilis oxyfera” is a recently described intra-aerobic methanotroph that is assumed to use nitric oxide to generate internal oxygen to oxidize methane via the conventional aerobic pathway, including the monooxygenase reaction. Previous genome analysis has suggested that, like the verrucomicrobial methanotrophs, “
Ca.
Methylomirabilis oxyfera” encodes and transcribes genes for the Calvin-Benson-Bassham (CBB) cycle for carbon assimilation. Here we provide multiple independent lines of evidence for autotrophic carbon dioxide fixation by “
Ca.
Methylomirabilis oxyfera” via the CBB cycle. The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), a key enzyme of the CBB cycle, in cell extracts from an “
Ca.
Methylomirabilis oxyfera” enrichment culture was shown to account for up to 10% of the total methane oxidation activity. Labeling studies with whole cells in batch incubations supplied with either
13
CH
4
or [
13
C]bicarbonate revealed that “
Ca.
Methylomirabilis oxyfera” biomass and lipids became significantly more enriched in
13
C after incubation with
13
C-labeled bicarbonate (and unlabeled methane) than after incubation with
13
C-labeled methane (and unlabeled bicarbonate), providing evidence for autotrophic carbon dioxide fixation. Besides this experimental approach, detailed genomic and transcriptomic analysis demonstrated an operational CBB cycle in “
Ca.
Methylomirabilis oxyfera.” Altogether, these results show that the CBB cycle is active and plays a major role in carbon assimilation by “
Ca.
Methylomirabilis oxyfera” bacteria. Our results suggest that autotrophy might be more widespread among methanotrophs than was previously assumed and implies that a methanotrophic community in the environment is not necessarily revealed by
13
C-depleted lipids.
Evaluation of a Loop-Mediated Isothermal Amplification Suite for the Rapid, Reliable, and Robust Detection of Shiga Toxin-Producing Escherichia coli in Produce
Authors: Wang Fei , Yang Qianru , Qu Yinzhi , Meng Jianghong , Ge Beilei
Published: February 2014

Shiga toxin-producing
Escherichia coli
(STEC) strains are a leading cause of produce-associated outbreaks in the United States. Rapid, reliable, and robust detection methods are needed to better ensure produce safety. We recently developed a loop-mediated isothermal amplification (LAMP) suite for STEC detection. In this study, the STEC LAMP suite was comprehensively evaluated against real-time quantitative PCR (qPCR) using a large panel of bacterial strains (
n
= 156) and various produce items (several varieties of lettuce, spinach, and sprouts). To simulate real-world contamination events, produce samples were surface inoculated with a low level (1.2 to 1.8 CFU/25 g) of individual STEC strains belonging to seven serogroups (O26, O45, O103, O111, O121, O145, and O157) and held at 4°C for 48 h before testing. Six DNA extraction methods were also compared using produce enrichment broths. All STEC targets and their subtypes were accurately detected by the LAMP suite. The detection limits were 1 to 20 cells per reaction in pure culture and 10
5
to 10
6
CFU per 25 g (i.e., 10
3
to 10
4
CFU per g) in produce, except for strains harboring the
stx
2c
,
eae
-β, and
eae
-θ subtypes. After 6 to 8 h of enrichment, the LAMP suite achieved accurate detection of low levels of STEC strains of various
stx
2
and
eae
subtypes in lettuce and spinach varieties but not in sprouts. A similar trend of detection was observed for qPCR. The PrepMan Ultra sample preparation reagent yielded the best results among the six DNA extraction methods. This research provided a rapid, reliable, and robust method for detecting STEC in produce during routine sampling and testing. The challenge with sprouts detection by both LAMP and qPCR calls for special attention to further analysis.
Biochemical Analysis of Recombinant AlkJ from Pseudomonas putida Reveals a Membrane-Associated, Flavin Adenine Dinucleotide-Dependent Dehydrogenase Suitable for the Biosynthetic Production of Aliphatic Aldehydes
Authors: Kirmair Ludwig , Skerra Arne
Published: February 2014

The noncanonical alcohol dehydrogenase AlkJ is encoded on the alkane-metabolizing
alk
operon of the mesophilic bacterium
Pseudomonas putida
GPo1. To gain insight into the enzymology of AlkJ, we have produced the recombinant protein in
Escherichia coli
and purified it to homogeneity using His
6
tag affinity and size exclusion chromatography (SEC). Despite synthesis in the cytoplasm, AlkJ was associated with the bacterial cell membrane, and solubilization with
n
-dodecyl-β-
d
-maltoside was necessary to liberate the enzyme. SEC and spectrophotometric analysis revealed a dimeric quaternary structure with stoichiometrically bound reduced flavin adenine dinucleotide (FADH
2
). The holoenzyme showed thermal denaturation at moderate temperatures around 35°C, according to both activity assay and temperature-dependent circular dichroism spectroscopy. The tightly bound coenzyme was released only upon denaturation with SDS or treatment with urea-KBr and, after air oxidation, exhibited the characteristic absorption spectrum of FAD. The enzymatic activity of purified AlkJ for 1-butanol, 1-hexanol, and 1-octanol as well as the
n
-alkanol derivative ω-hydroxy lauric acid methyl ester (HLAMe) was quantified in the presence of the artificial electron acceptors phenazine methosulfate (PMS) and 2,6-dichlorophenolindophenol (DCPIP), indicating broad substrate specificity with the lowest activity on the shortest alcohol, 1-butanol. Furthermore, AlkJ was able to accept as cosubstrates/oxidants the ubiquinone derivatives Q
0
and Q
1
, also in conjunction with cytochrome
c
, which suggests coupling to the bacterial respiratory chain of this membrane-associated enzyme in its physiological environment. Using gas chromatographic analysis, we demonstrated specific biocatalytic conversion by AlkJ of the substrate HLAMe to the industrially relevant aldehyde, thus enabling the biotechnological production of 12-amino lauric acid methyl ester via subsequent enzymatic transamination.
A Conserved Streptococcal Membrane Protein, LsrS, Exhibits a Receptor-Like Function for Lantibiotics
Authors: Biswas Saswati , Biswas Indranil
Published: February 2014

Streptococcus mutans
strain GS-5 produces a two-peptide lantibiotic, Smb, which displays inhibitory activity against a broad spectrum of bacteria, including other streptococci. For inhibition, lantibiotics must recognize specific receptor molecules present on the sensitive bacterial cells. However, so far no such receptor proteins have been identified for any lantibiotics. In this study, using a powerful transposon mutagenesis approach, we have identified in
Streptococcus pyogenes
a gene that exhibits a receptor-like function for Smb. The protein encoded by that gene, which we named LsrS, is a membrane protein belonging to the CAAX protease family. We also found that nisin, a monopeptide lantibiotic, requires LsrS for its optimum inhibitory activity. However, we found that LsrS is not required for inhibition by haloduracin and galolacticin, both of which are two-peptide lantibiotics closely related to Smb. LsrS appears to be a well-conserved protein that is present in many streptococci, including
S. mutans
. Inactivation of SMU.662, an LsrS homolog, in
S. mutans
strains UA159 and V403 rendered the cells refractory to Smb-mediated killing. Furthermore, overexpression of LsrS in
S. mutans
created cells more susceptible to Smb. Although LsrS and its homolog contain the CAAX protease domain, we demonstrate that inactivation of the putative active sites on the LsrS protein has no effect on its receptor-like function. This is the first report describing a highly conserved membrane protein that displays a receptor-like function for lantibiotics.
Conditional, Temperature-Induced Proteolytic Regulation of Cyanobacterial RNA Helicase Expression
Authors: Tarassova Oxana S. , Chamot Danuta , Owttrim George W.
Published: February 2014

Conditional proteolysis is a crucial process regulating the abundance of key regulatory proteins associated with the cell cycle, differentiation pathways, or cellular response to abiotic stress in eukaryotic and prokaryotic organisms. We provide evidence that conditional proteolysis is involved in the rapid and dramatic reduction in abundance of the cyanobacterial RNA helicase, CrhR, in response to a temperature upshift from 20 to 30°C. The proteolytic activity is not a general protein degradation response, since proteolysis is only present and/or functional in cells grown at 30°C and is only transiently active at 30°C. Degradation is also autoregulatory, since the CrhR proteolytic target is required for activation of the degradation machinery. This suggests that an autoregulatory feedback loop exists in which the target of the proteolytic machinery, CrhR, is required for activation of the system. Inhibition of translation revealed that only elongation is required for induction of the temperature-regulated proteolysis, suggesting that translation of an activating factor was already initiated at 20°C. The results indicate that
Synechocystis
responds to a temperature shift via two independent pathways: a CrhR-independent sensing and signal transduction pathway that regulates induction of
crhR
expression at low temperature and a CrhR-dependent conditional proteolytic pathway at elevated temperature. The data link the potential for CrhR RNA helicase alteration of RNA secondary structure with the autoregulatory induction of conditional proteolysis in the response of
Synechocystis
to temperature upshift.
Regulation of Expression of
abcA
and Its Response to Environmental Conditions
Authors: Villet Regis A. , Truong-Bolduc Que Chi , Wang Yin , Estabrooks Zoe , Medeiros Heidi , Hooper David C.
Published: February 2014

The ATP-dependent transporter gene
abcA
in
Staphylococcus aureus
confers resistance to hydrophobic β-lactams. In strain ISP794,
abcA
is regulated by the transcriptional regulators MgrA and NorG and shares a 420-nucleotide intercistronic region with the divergently transcribed
pbp4
gene, which encodes the transpeptidase Pbp4. Exposure of exponentially growing cells to iron-limited media, oxidative stress, and acidic pH (5.5) for 0.5 to 2 h had no effect on
abcA
expression. In contrast, nutrient limitation produced a significant increase in
abcA
transcripts. We identified three additional regulators (SarA, SarZ, and Rot) that bind to the overlapping promoter region of
abcA
and
pbp4
in strain MW2 and investigated their role in the regulation of
abcA
expression. Expression of
abcA
is decreased by 10.0-fold
in vivo
in a subcutaneous abscess model.
In vitro
,
abcA
expression depends on
rot
and
sarZ
regulators. Moenomycin A exposure of strain MW2 produced an increase in
abcA
transcripts. Relative to MW2, the MIC of moenomycin was decreased 8-fold for MW2Δ
abcA
and increased 10-fold for the MW2
abcA
overexpresser, suggesting that moenomycin is a substrate of AbcA.
The
mthA
Mutation Conferring Low-Level Resistance to Streptomycin Enhances Antibiotic Production in Bacillus subtilis by Increasing the
S
-Adenosylmethionine Pool Size
Authors: Tojo Shigeo , Kim Ji-Yun , Tanaka Yukinori , Inaoka Takashi , Hiraga Yoshikazu , Ochi Kozo
Published: February 2014

Certain Str
r
mutations that confer low-level streptomycin resistance result in the overproduction of antibiotics by
Bacillus subtilis
. Using comparative genome-sequencing analysis, we successfully identified this novel mutation in
B. subtilis
as being located in the
mthA
gene, which encodes
S
-adenosylhomocysteine/methylthioadenosine nucleosidase, an enzyme involved in the
S
-adenosylmethionine (SAM)-recycling pathways. Transformation experiments showed that this
mthA
mutation was responsible for the acquisition of low-level streptomycin resistance and overproduction of bacilysin. The
mthA
mutant had an elevated level of intracellular SAM, apparently acquired by arresting SAM-recycling pathways. This increase in the SAM level was directly responsible for bacilysin overproduction, as confirmed by forced expression of the
metK
gene encoding SAM synthetase. The
mthA
mutation fully exerted its effect on antibiotic overproduction in the genetic background of
rel

+

but not the
rel
mutant, as demonstrated using an
mthA relA
double mutant. Strikingly, the
mthA
mutation activated, at the transcription level, even the dormant ability to produce another antibiotic, neotrehalosadiamine, at concentrations of 150 to 200 μg/ml, an antibiotic not produced (<1 μg/ml) by the wild-type strain. These findings establish the significance of SAM in initiating bacterial secondary metabolism. They also suggest a feasible methodology to enhance or activate antibiotic production, by introducing either the
rsmG
mutation to
Streptomyces
or the
mthA
mutation to eubacteria, since many eubacteria have
mthA
homologues.
Effect of Bidirectional Rotation of An Acupuncture Needle at Li10 on Acupuncture Needle Sensation and Experimentally-Induced Contact Heat Pain in Healthy Human Volunteers
Authors: Benham Alex , Johnson Mark I
Published: February 2014

Introduction

There is insufficient evidence of a relationship between acupuncture needle sensations ( de qi) and hypoalgesia. The aim of this study was to investigate the effects of bidirectional needle rotation at LI10 on acupuncture needle sensations and heat pain thresholds.

Methods

Twenty-two healthy participants received one acupuncture needle at LI10 with bidirectional rotation of the needle in one experimental session and one acupuncture needle at LI10 with mock rotation in a separate session, in a randomised order. Measurements of heat pain thresholds were taken before needle insertion, during needle retention and 15 min after needle removal. At each measurement time point, participants rated needle sensations using the Massachusetts Acupuncture Sensation Scale (MASS) and a visual analogue scale (VAS) of overall intensity of needle sensation.

Results

Bidirectional needle rotation produced significantly higher scores for VAS, MASStotal, MASSpain and MASSsensation compared with mock rotation (all p<0.001). There were significantly higher pain thresholds relative to pre-intervention baseline during (p=0.014) and after (p<0.001) bidirectional needle rotation but not during (p=0.1) or after (p=0.62) mock bidirectional needle rotation. Bidirectional needle rotation increased the pain threshold relative to baseline 15 min after the needles were removed (p=0.009). A significant but low correlation between needle sensation and change in pain threshold after needling was only found when data from mock and rotation interventions were combined.

Conclusions

Needle rotation increases the magnitude of hypoalgesia. There is tentative evidence that needle sensation may be associated with the amount of change in pain threshold.
Disseminated cryptococcosis involving the head and neck
Authors: Lazzara Matthew , Joshi Arjun
Published: February 2014

A middle-aged patient with HIV presented with very distinctive maculopapular cutaneous lesions involving the face and lymphadenopathy confined to the neck. A diagnosis of disseminated cryptococcosis was made based on pathological analysis of lymph node and skin lesions.
Loeys-Dietz syndrome: life threatening aortic dissection diagnosed on routine family screening
Authors: Martin Claire A , Clowes Virginia E , Cooper John P
Published: February 2014

A 52-year-old man was found to have a severely dilated aortic root and a Stanford type A dissection on familial screening echocardiography, following diagnosis of a dilated aorta in his son. The dissection required urgent surgical repair. Clinical examination suggested features of Loeys-Dietz syndrome type II, and subsequent demonstration of a mutation in theTGFBR1gene in the patient and his son confirmed the diagnosis. This article highlights the high prevalence of inherited conditions in dilated aortic root presentations and the importance of family screening and surveillance to allow early surgical intervention.
Engagement techniques and playing level impact the biomechanical demands on rugby forwards during machine-based scrummaging
Authors: Preatoni Ezio , Stokes Keith A , England Michael E , Trewartha Grant
Published: February 2014

Objectives

This cross-sectional study investigated the factors that may influence the physical loading on rugby forwards performing a scrum by studying the biomechanics of machine-based scrummaging under different engagement techniques and playing levels.

Methods

34 forward packs from six playing levels performed repetitions of five different types of engagement techniques against an instrumented scrum machine under realistic training conditions. Applied forces and body movements were recorded in three orthogonal directions.

Results

The modification of the engagement technique altered the load acting on players. These changes were in a similar direction and of similar magnitude irrespective of the playing level. Reducing the dynamics of the initial engagement through a fold-in procedure decreased the peak compression force, the peak downward force and the engagement speed in excess of 30%. For example, peak compression (horizontal) forces in the professional teams changed from 16.5 (baseline technique) to 8.6 kN (fold-in procedure). The fold-in technique also reduced the occurrence of combined high forces and head-trunk misalignment during the absorption of the impact, which was used as a measure of potential hazard, by more than 30%. Reducing the initial impact did not decrease the ability of the teams to produce sustained compression forces.

Conclusions

De-emphasising the initial impact against the scrum machine decreased the mechanical stresses acting on forward players and may benefit players’ welfare by reducing the hazard factors that may induce chronic degeneration of the spine.
Cost-effectiveness of initial stress cardiovascular MR, stress SPECT or stress echocardiography as a gate-keeper test, compared with upfront invasive coronary angiography in the investigation and management of patients with stable chest pain: mid-term outcomes from the CECaT randomised controlled trial
Authors: Thom Howard , West Nicholas E J , Hughes Vikki , Dyer Matthew , Buxton Martin , Sharples Linda D , Jackson Christopher H , Crean Andrew M ,   The CECaT study group
Published: February 2014

Objectives

To compare outcomes and cost-effectiveness of various initial imaging strategies in the management of stable chest pain in a long-term prospective randomised trial.

Setting

Regional cardiothoracic referral centre in the east of England.

Participants

898 patients (69% man) entered the study with 869 alive at 2 years of follow-up. Patients were included if they presented for assessment of stable chest pain with a positive exercise test and no prior history of ischaemic heart disease. Exclusion criteria were recent infarction, unstable symptoms or any contraindication to stress MRI.

Primary outcome measures

The primary outcomes of this follow-up study were survival up to a minimum of 2 years post-treatment, quality-adjusted survival and cost-utility of each strategy.

Results

898 patients were randomised. Compared with angiography, mortality was marginally higher in the groups randomised to cardiac MR (HR 2.6, 95% CI 1.1 to 6.2), but similar in the single photon emission CT-methoxyisobutylisonitrile (SPECT-MIBI; HR 1.0, 95% CI 0.4 to 2.9) and ECHO groups (HR 1.6, 95% CI 0.6 to 4.0). Although SPECT-MIBI was marginally superior to other non-invasive tests there were no other significant differences between the groups in mortality, quality-adjusted survival or costs.

Conclusions

Non-invasive cardiac imaging can be used safely as the initial diagnostic test to diagnose coronary artery disease without adverse effects on patient outcomes or increased costs, relative to angiography. These results should be interpreted in the context of recent advances in imaging technology.

Trial registration

ISRCTN 47108462, UKCRN 3696.
Validity of instruction leaflets for parents to measure their child's weight and height at home: results obtained from a randomised controlled trial
Authors: Huybrechts Inge , Beirlaen Celine , De Vriendt Tineke , Slimani Nadia , Pisa Pedro T , Schouppe Elien , De Coene Anja , De Bacquer Dirk , De Henauw Stefaan , Himes John H
Published: February 2014

Objectives

To compare the validity of parent-reported height, weight and body mass index (BMI) values of children (aged 4–10 years), when measured at home by means of newly developed instruction leaflets in comparison with simple estimated parental reports.

Design

Randomised controlled trial with control and intervention group using simple randomisation.

Setting

Belgian children and their parents recruited via schools (multistage cluster sampling design).

Participants

164 Belgian children (53% male; participation rate 62%).

Intervention

Parents completed a questionnaire including questions about the height and weight of their child. Parents in the intervention group received instruction leaflets to measure their child's weight and height. Classes were randomly allocated to the intervention and control groups. Nurses measured height and weight following standardised procedures up to 2 weeks after parental reports.

Outcome measures

Weight, height and BMI category of the child were derived from the index measurements and the parental reports.

Results

Mean parent-reported weight was slightly more underestimated in the intervention group than in the control group relative to the index weights. However, for all three parameters (weight, height and BMI), correlations between parental reports and nurse measurements were higher in the intervention group. Sensitivity for underweight and overweight/obesity was respectively, 75% and 60% in the intervention group, and 67% and 43% in the control group. Weighed κ for classifying children in the correct BMI category was 0.30 in the control group and was 0.51 in the intervention group.

Conclusions

Although mean parent-reported weight was slightly more underestimated in the intervention than in the control group, correlations were higher and there was considerably less misclassification into valid BMI categories for the intervention group. This pattern suggests that most of the parental deviations from the index measurements were probably due to random errors of measurement and that diagnostic measures could improve by encouraging parents to measure their children's weight and height at home by means of instruction leaflets.
Sick leave patterns as predictors of disability pension or long-term sick leave: a 6.75-year follow-up study in municipal eldercare workers
Authors: Stapelfeldt Christina Malmose , Nielsen Claus Vinther , Andersen Niels Trolle , Krane Line , Borg Vilhelm , Fleten Nils , Jensen Chris
Published: February 2014

Objectives

The aim was to study whether a workplace-registered frequent short-term sick leave spell pattern was an early indicator of future disability pension or future long-term sick leave among municipal eldercare workers.

Setting

The municipal healthcare sector in the city of Aarhus, which is the second largest city in Denmark.

Participants

All elder care employees who worked the entire year of 2004 in the municipality of Aarhus, Denmark (N=2774). The employees’ sick leave days during 2004 were categorised into: 0–2 and 3–17 short (1–7 days) spells, 2–13 mixed short and long (8+ days) spells and long spells only. Student workers (n=180), employees who were absent due to maternal/paternal leave (n=536) and employees who did not work the entire year of 2004 (n=1218) were not included.

Primary outcome

Disability pension and long-term sick leave (≥8 weeks) were subsequently identified in a National register. The cumulative incidence proportion as a function of follow-up weeks was estimated using the Kaplan-Meier curve. The relative cumulative incidence (RR) of experiencing events within 352 weeks was analysed in a generalised linear regression model using the pseudo values method adjusted for age, occupation, unfavourable work factors and sick leave length.

Results

A frequent short-term and a mixed sick leave pattern showed RRs of being granted a disability pension of 2.08 (95% CI 1.00 to 4.35) and 2.61 (95% CI 1.33 to 5.12) compared with 0–2 short spells. The risk of long-term sick leave was significantly increased for all sick leave patterns compared with 0–2 short spells. Adding sick leave length to the models attenuated all RRs and they became non-significant.

Conclusions

Sick leave length was a better indicator of future workability than spell frequency. Preventive actions should target employees engaged in homecare. The more sick leave days the greater the preventive potential seems, irrespective of spell frequency.
Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review
Authors: Brurberg Kjetil Gundro , Fønhus Marita Sporstøl , Larun Lillebeth , Flottorp Signe , Malterud Kirsti
Published: February 2014

Objective

To identify case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), and explore how the validity of case definitions can be evaluated in the absence of a reference standard.

Design

Systematic review.

Setting

International.

Participants

A literature search, updated as of November 2013, led to the identification of 20 case definitions and inclusion of 38 validation studies.

Primary and secondary outcome measure

Validation studies were assessed for risk of bias and categorised according to three validation models: (1) independent application of several case definitions on the same population, (2) sequential application of different case definitions on patients diagnosed with CFS/ME with one set of diagnostic criteria or (3) comparison of prevalence estimates from different case definitions applied on different populations.

Results

A total of 38 studies contributed data of sufficient quality and consistency for evaluation of validity, with CDC-1994/Fukuda as the most frequently applied case definition. No study rigorously assessed the reproducibility or feasibility of case definitions. Validation studies were small with methodological weaknesses and inconsistent results. No empirical data indicated that any case definition specifically identified patients with a neuroimmunological condition.

Conclusions

Classification of patients according to severity and symptom patterns, aiming to predict prognosis or effectiveness of therapy, seems useful. Development of further case definitions of CFS/ME should be given a low priority. Consistency in research can be achieved by applying diagnostic criteria that have been subjected to systematic evaluation.
Intracranial haemorrhage in thrombocytopenic haematology patients—a nested case–control study: the InCiTe study protocol
Authors: Estcourt Lise J , Stanworth Simon J , Collett Dave , Murphy Mike F
Published: February 2014

Introduction

Intracranial haemorrhage (ICH) is one of the most serious side-effects of severe thrombocytopenia in haematology patients. ICH is rare, but can have devastating consequences (death or major morbidity). It is unknown why some patients with severe thrombocytopenia bleed and others do not.

Study aims

Primary aim was to identify risk factors for ICH in patients with haematological malignancies. Secondary aims were to identify short-term outcomes for these patients at 30 days (major morbidity and mortality) and produce a more accurate estimate of ICH incidence in this population. This information is key to identifying means to improve treatment and quality of care.

Methods/analysis

This is a UK-wide case–control study of ICH nested within a 4-year prospective surveillance study set up specifically for the case–control study. Each case will be matched to one control. Cases will be adult haematology patients (≥16 years) who have had any type or severity of ICH who are receiving, about to receive or have just received myeloablative chemotherapy (defined as chemotherapy expected to cause a significant thrombocytopenia <50×109/L for >5 days) or a haemopoietic stem cell transplant. Only patients being treated with curative intent will be included. Controls will be patients who fulfil the same inclusion criteria as cases (apart from ICH) and were treated at the same hospital immediately before the index case. Cases and controls will be matched to type of treatment (myeloablative chemotherapy or haemopoietic stem cell transplant). Hospitals across the UK will participate in a monthly email reporting strategy (started June 2011), as to whether a case of ICH occurred during the preceding calendar month. Case and control forms will be sent to any hospital reporting an eligible case. Conditional logistic regression will be used to calculate ORs. Denominator data for incidence estimates will use national registry data.

Study Registration

ISRCTN05026912 (prospective registration). NIHR Portfolio (UKCRN ID 10712).
A multicentre cohort study assessing day of week effect and outcome from emergency appendicectomy
Authors: Ferguson Henry JM , Hall Nigel J , Bhangu Aneel
Published: February 2014

Background

There is evidence to suggest that patients undergoing treatment at weekends may be subject to different care processes and outcomes compared with weekdays. This study aimed to determine whether clinical outcomes from weekend appendicectomy are different from those performed on weekdays.

Method

Multicentre cohort study during May–June 2012 from 95 centres (89 within the UK). The primary outcome was the 30-day adverse event rate. Multilevel modelling was used to account for clustering within hospitals while adjusting for case mix to produce adjusted ORs and 95% CIs.

Results

When compared with Monday, there were no significant differences for other days of the week considering 30-day adverse events in adjusted models. On Sunday, rates of simple appendicitis were highest, and rates of normal (OR 0.62, 95% CI 0.42 to 0.90) and complex appendicitis (OR 0.65, 95% CI 0.46 to 0.93) lowest. This was accompanied by a 43% lower likelihood in use of laparoscopy on Sunday (OR 0.47, 95% CI 0.32 to 0.69), accompanied by the lowest level of consultant presence for the week. When pooling weekends and weekdays, laparoscopy use remained less likely at the weekend (OR 0.68, 95% CI 0.55 to 0.83), with no significant difference for 30-day adverse event rate (OR 1.01, 95% CI 0.80 to 1.29).

Conclusions

This study found that weekend appendicectomy was not associated with increased 30-day adverse events. It cannot rule out smaller increases that may be shown by larger studies. It further illustrated that patients operated on at weekends were subject to different care processes, which may expose them to risk.
Improving room layouts for venepuncture, cannulation and ABG equipment on surgical wards
Authors: Pedley Ryan , Whitehouse Anna , Hammond Sarah
Published: February 2014

The Productive Ward series has effectively helped to standardise the storage of equipment in hospital ward treatment rooms; however, in our organisation equipment for venepunture and cannulation had been excluded. This resulted in clinicians having to navigate several unfamiliar environments while on-call and hence waste valuable time searching for basic equipment.

We aimed to make it easier to locate and identify the basic equipment used for cannulation, venepuncture, and arterial blood gas sampling and more efficient to collect. We examined the initial layout of equipment on four surgical wards in a large teaching hospital. The time taken for junior doctors, nurses, health care assistants, and physician assistants to gather equipment on these wards was recorded along with a process map of steps involved. Our intervention was to relocate the equipment into adjacent storage and make it easily identifiable by the use of a 'red dot'. Following these changes we repeated the measurements.

There was an overall reduction in the mean time taken to gather the equipment required to insert a venous cannula on an unfamiliar ward from 2 min 41 s pre-intervention (range 52 s to 6 mins 58 s, n = 23) to 26 s post-intervention (range 8 s to 1 min 20 s, n = 51). Additionally, the number of steps involved in the process was reduced from 16 to five. All of the 32 junior doctors surveyed felt that faster identification improved patient safety.

A significant reduction in the time wasted by clinicians searching for venepuncture equipment on surgical wards has been achieved by simplifying the storage, layout, and identification of this kit. The accumulated benefit includes increased productivity, familiarity, and safety, which is paramount when attending unwell patients on unfamiliar wards.
Thrombus density predicts successful recanalization with Solitaire stent retriever thrombectomy in acute ischemic stroke
Authors: Mokin Maxim , Morr Simon , Natarajan Sabareesh K , Lin Ning , Snyder Kenneth V , Hopkins L Nelson , Siddiqui Adnan H , Levy Elad I
Published: February 2014

Background

Thrombus characteristics, including Hounsfield unit (HU) value to measure density and thrombus volume and length, can predict successful recanalization following IV thrombolysis with recombinant tissue plasminogen activator. Conflicting and limited data exist regarding the value of assessing thrombus properties in acute stroke cases treated with endovascular IA approaches.

Methods

We retrospectively reviewed cases of anterior circulation acute ischemic stroke in which a Solitaire stent retriever (ev3-Covidien) was the primary treatment device. We measured the following thrombus characteristics: absolute and corrected HU values; thrombus length and volume; clot burden score; and vessel bifurcation involvement. Fisher's exact test and the t test were used to study the association between these clot characteristics and successful recanalization (Thrombolysis in Cerebral Infarction (TICI) score 2b–3).

Results

We identified 41 patients with anterior circulation stroke treated with the Solitaire stent retriever as the primary treatment device. Successful recanalization (TICI score 2b–3) was achieved in 59% of cases. Higher absolute and corrected HU values were strongly predictive of successful recanalization (49.9±7.6 vs 43.8±6.6, p=0.01 for absolute HU values and 1.2±0.2 vs 1.0±0.1, p=0.03 for HU ratio in TICI 2b–3 and TICI 0–2a groups, respectively). There was no significant difference between recanalization and non-recanalization groups in the other thrombus characteristics studied.

Conclusions

In acute stroke treated with Solitaire stent retriever thrombectomy, higher thrombus HU values are predictive of successful recanalization. Such information can be used in decision making when estimating recanalization success rate with different endovascular treatment approaches.
Endovascular superselective treatment of brain tumors: a new endovascular era? A quick review
Authors: Peschillo Simone , Miscusi Massimo , Missori Paolo
Published: February 2014

Background

Intra-arterial therapy for malignant brain tumors, especially high-grade gliomas, has been administered since the 1950s and 1960s when the structure of the blood–brain barrier was first described. However, only with the advent of modern techniques used by endovascular neurosurgeons has it been possible to proceed with the release of chemotherapeutic agents in an ultraselective mode by superselective intra-arterial cerebral infusion (SIACI).

Methods

A brief review was performed of all the published works from January 2000 to December 2013 in which the main issue was the superselective endovascular treatment of brain tumors with chemotherapy drugs.

Results

Intra-arterial non-selective therapy has been reported to be effective in chemosensitive tumors whereas the results in glioblastoma, at least in the pre-bevacizumab era, have been disappointing.

Conclusions

If the SIACI method for delivering bevacizumab after disruption of the blood–brain barrier is proved to be safe and effective in larger phase II and III trials, this paradigm may significantly alter the way chemotherapies are delivered to patients with both diffusely infiltrating low-grade and those with high-grade malignant brainstem gliomas and open a new endovascular era.
Blood vessel repair and regeneration in the ischaemic heart
Authors: Zhang Huajun , van Olden Casper , Sweeney Dominic , Martin-Rendon Enca
Published: February 2014

The term ‘therapeutic angiogenesis’ originated almost two decades ago, following evidence that factors that promote blood vessel formation could be delivered to ischaemic tissues and restore blood flow. Following this proof-of-principle, safety and efficacy of the best-studied angiogenic factors (eg, vascular endothelial growth factor) were demonstrated in early clinical studies. Promising results led to the development of larger controlled trials that, unfortunately, have failed to satisfy the initial expectations of therapeutic angiogenesis for ischaemic heart disease. As the quest to delay the progression to heart failure secondary to ischaemic heart disease continues, alternative therapies have emerged as potential novel treatments to improve myocardial reperfusion and long-term heart function. The disappointing results of the clinical studies using angiogenic factors were followed by mixed results from the cell therapy trials. This review reflects the current angiogenic strategies for the ischaemic heart, their limitations and discusses future perspectives in the light of recent scientific and clinical evidence. It is proposed that combination therapies may be a new direction to advance therapeutic repair and regeneration of blood vessels in the ischaemic heart.
Different redox sensitivity of endoplasmic reticulum associated degradation clients suggests a novel role for disulphide bonds in secretory proteins
Authors: Medraño-Fernandez Iria , Fagioli Claudio , Mezghrani Alexandre , Otsu Mieko , Sitia Roberto
Published: February 2014

To maintain proteostasis in the endoplasmic reticulum (ER), terminally misfolded secretory proteins must be recognized, partially unfolded, and dislocated to the cytosol for proteasomal destruction, in a complex process called ER-associated degradation (ERAD). Dislocation implies reduction of inter-chain disulphide bonds. When in its reduced form, protein disulphide isomerase (PDI) can act not only as a reductase but also as an unfoldase, preparing substrates for dislocation. PDI oxidation by Ero1 favours substrate release and transport across the ER membrane. Here we addressed the redox dependency of ERAD and found that DTT stimulates the dislocation of proteins with DTT-resistant disulphide bonds (i.e., orphan Ig-μ chains) but stabilizes a ribophorin mutant (Ri332) devoid of them. DTT promotes the association of Ri332, but not of Ig-µ, with PDI. This discrepancy may suggest that disulphide bonds in cargo proteins can be utilized to oxidize PDI, hence facilitating substrate detachment and degradation also in the absence of Ero1. Accordingly, Ero1 silencing retards Ri332 degradation, but has little if any effect on Ig-µ. Thus, some disulphides can increase the stability and simultaneously favour quality control of secretory proteins.
Stabilizing, non-covalent interactions in the solid state structure of novel aryltin hydrides and halogenides
Authors: Zeppek Cathrin , Fischer Roland C. , Torvisco Ana , Uhlig Frank
Published: February 2014

A group of novel aryltin chlorides, bromides and hydrides (ArnSnY4-n) (Ar = o-tolyl, 2,6-xylyl, 1-naphthyl, 2-naphthyl, p-n-butylphenyl; Y = Cl, Br, H) have been synthesized and structurally characterized via X-ray diffraction. These compounds display noncovalent intermolecular interactions in the form of edge to face, π–π stacking and C–H···π interactions resulting in discrete arrangements in the solid state. The strength of these interactions and their effect on resulting structural parameters, as well as the consequence of the aromatic substituent on the type of interactions present, will be highlighted and discussed.
Activity patterns of nucleolar organizer region during spermatogenesis of different curimatid species (Characiformes: Curimatidae)
Authors: Sampaio Tatiane R. , Pires Larissa B. , da Rosa Renata , Dias Ana Lúcia
Published: February 2014

The nucleolus is an important nuclear structure where transcription of ribosomal DNA (rDNA) takes place. During mitotic division, the nucleolus passes through different processes that inactivate rDNA transcription; in meiosis, its reassembly takes place during telophase II. The objective of this study was to identify the activity patterns and localization of nucleolar organizer regions (NORs) during meiotic division in fish species of the family Curimatidae. For this analysis, the meiotic division in five curimatid species was studied using silver nitrate impregnation, fluorescent in situ hybridization (FISH), and base-specific fluorochrome staining. Silver nitrate staining indicated the presence of a nucleolus in interphase nuclei, one chromosome pair in the spermatogonial metaphases, and one bivalent at the pachytene stage. No Ag-NORs were identified for cells at the diplotene, diakinesis, metaphase I, or metaphase II stages; however, FISH confirmed the presence of Ag-NORs in the nuclei, in spermatogonia, and at the pachytene phase. FISH identified this region during the other stages of meiosis, as did fluorochrome CMA3 staining, which revealed fluorescent marks corresponding to NORs during all stages of meiosis analyzed. The gene activity and localization of this ribosomal sequence during the different stages involved will also be discussed.
Quaternion Algebras over Curves of Genus One Without Rational Points
Authors: Pumplün Susanne
Published: February 2014

Quaternion algebras over curves of genus one without rational points over perfect fields of characteristic not two are classified. As a consequence, all quaternion algebras over the function field of such a curve, which are unramified everywhere, are classified.
On (m,n)-Injective Modules and (m,n)-Coherent Rings
Authors: Zhang Xiaoxiang , Chen Jianlong , Zhang Juan
Published: February 2014

Let R be a ring. For two fixed positive integers m and n, a right R-module M is called (m,n)-injective in case every right R-homomorphism from an n-generated submodule of Rm to M extends to one from Rm to M. R is said to be left (m,n)-coherent if each n-generated submodule of the left R-module Rm is finitely presented. In this paper, we give some new characterizations of (m,n)-injective modules. We also derive various equivalent conditions for a ring to be left (m,n)-coherent. Some known results on coherent rings are obtained as corollaries.
On Vanishing of Generalized Local Cohomology Modules
Authors: Divaani-Aazar K. , Sazeedeh R. , Tousi M.
Published: February 2014

Let [Formula: see text] denote an ideal of a d-dimensional Gorenstein local ring R, and M and N two finitely generated R-modules with pd M < ∞. It is shown that [Formula: see text] if and only if [Formula: see text] for all [Formula: see text].
Degeneration, Rigidity and Irreducible Components of Hopf algebras
Authors: Makhlouf Abdenacer
Published: February 2014

The aim of this work is to discuss the concepts of degeneration, deformation and rigidity of Hopf algebras and to apply them to the geometric study of the varieties of Hopf algebras. The main result is the description of the n-dimensional rigid Hopf algebras and the irreducible components for n<14 and n = p2 with p a prime number.
Robinson–Schensted–Knuth Correspondence and Weak Polynomial Identities of M1,1(E)
Authors: Di Vincenzo Onofrio Mario , La Scala Roberto
Published: February 2014

In this paper, it is proved that the ideal Iw of the weak polynomial identities of the superalgebra M1,1(E) is generated by the proper polynomials [x1, x2, x3] and [x2, x1] [x3, x1] [x4, x1]. This is proved for any infinite field F of characteristic different from 2. Precisely, if B is the subalgebra of the proper polynomials of F, we determine a basis and the dimension of any multihomogeneous component of the quotient algebra B / (B ∩ Iw). We also compute the Hilbert series of this algebra. One of the main tools of this paper is a variant we found of the Robinson–Schensted–Knuth correspondence defined for single semistandard tableaux of double shape.