bluuebunny/crossref_metadata_2025 huggingface dataset:
Styrene Oxide Isomerase of Rhodococcus opacus 1CP, a Highly Stable and Considerably Active Enzyme
Authors: Oelschlägel Michel , Gröning Janosch A. D. , Tischler Dirk , Kaschabek Stefan R. , Schlömann Michael
Published: April 2012

Styrene oxide isomerase (SOI) is involved in peripheral styrene catabolism of bacteria and converts styrene oxide to phenylacetaldehyde. Here, we report on the identification, enrichment, and biochemical characterization of a novel representative from the actinobacterium
Rhodococcus opacus
1CP. The enzyme, which is strongly induced during growth on styrene, was shown to be membrane integrated, and a convenient procedure was developed to highly enrich the protein in active form from the wild-type host. A specific activity of about 370 U mg
−1
represents the highest activity reported for this enzyme class so far. This, in combination with a wide pH and temperature tolerance, the independence from cofactors, and the ability to convert a spectrum of substituted styrene oxides, makes a biocatalytic application imaginable. First, semipreparative conversions were performed from which up to 760 μmol of the pure phenylacetaldehyde could be obtained from 130 U of enriched SOI. Product concentrations of up to 76 mM were achieved. However, due to the high chemical reactivity of the aldehyde function, SOI was shown to be the subject of an irreversible product inhibition. A half-life of 15 min was determined at a phenylacetaldehyde concentration of about 55 mM, indicating substantial limitations of applicability and the need to modify the process.
Distribution of Genetic Marker Concentrations for Fecal Indicator Bacteria in Sewage and Animal Feces
Authors: Kelty Catherine A. , Varma Manju , Sivaganesan Mano , Haugland Richard A. , Shanks Orin C.
Published: April 2012

Very little is known about the density and distribution of fecal indicator bacteria (FIB) genetic markers measured by quantitative real-time PCR (qPCR) in fecal pollution sources. Before qPCR-based FIB technologies can be applied to waste management and public health risk applications, it is vital to characterize the concentrations of these genetic markers in pollution sources (i.e., untreated wastewater and animal feces). We report the distribution of rRNA genetic markers for several general FIB groups, including
Clostridium
spp.,
Escherichia coli
, enterococci, and
Bacteroidales
, as determined by qPCR on reference collections consisting of 54 primary influent sewage samples collected from treatment facilities across the United States and fecal samples representing 20 different animal species. Based on raw sewage sample collection data, individual FIB genetic markers exhibited a remarkable similarity in concentration estimates from locations across the United States ranging from Hawaii to Florida. However, there was no significant correlation between genetic markers for most FIB combinations (
P
> 0.05). In addition, large differences (up to 5 log
10
copies) in the abundance of FIB genetic markers were observed between animal species, emphasizing the importance of indicator microorganism selection and animal source contribution for future FIB applications.
Overexpression of Genes Encoding Glycolytic Enzymes in Corynebacterium glutamicum Enhances Glucose Metabolism and Alanine Production under Oxygen Deprivation Conditions
Authors: Yamamoto Shogo , Gunji Wataru , Suzuki Hiroaki , Toda Hiroshi , Suda Masako , Jojima Toru , Inui Masayuki , Yukawa Hideaki
Published: April 2012

We previously reported that
Corynebacterium glutamicum
strain Δ
ldhA
Δ
ppc
+
alaD
+
gapA
, overexpressing glyceraldehyde-3-phosphate dehydrogenase-encoding
gapA
, shows significantly improved glucose consumption and alanine formation under oxygen deprivation conditions (T. Jojima, M. Fujii, E. Mori, M. Inui, and H. Yukawa, Appl. Microbiol. Biotechnol. 87:159–165, 2010). In this study, we employ stepwise overexpression and chromosomal integration of a total of four genes encoding glycolytic enzymes (herein referred to as glycolytic genes) to demonstrate further successive improvements in
C. glutamicum
glucose metabolism under oxygen deprivation. In addition to
gapA
, overexpressing pyruvate kinase-encoding
pyk
and phosphofructokinase-encoding
pfk
enabled strain GLY2/pCRD500 to realize respective 13% and 20% improved rates of glucose consumption and alanine formation compared to GLY1/pCRD500. Subsequent overexpression of glucose-6-phosphate isomerase-encoding
gpi
in strain GLY3/pCRD500 further improved its glucose metabolism. Notably, both alanine productivity and yield increased after each overexpression step. After 48 h of incubation, GLY3/pCRD500 produced 2,430 mM alanine at a yield of 91.8%. This was 6.4-fold higher productivity than that of the wild-type strain. Intracellular metabolite analysis showed that
gapA
overexpression led to a decreased concentration of metabolites upstream of glyceraldehyde-3-phosphate dehydrogenase, suggesting that the overexpression resolved a bottleneck in glycolysis. Changing ratios of the extracellular metabolites by overexpression of glycolytic genes resulted in reduction of the intracellular NADH/NAD
+
ratio, which also plays an important role on the improvement of glucose consumption. Enhanced alanine dehydrogenase activity using a high-copy-number plasmid further accelerated the overall alanine productivity. Increase in glycolytic enzyme activities is a promising approach to make drastic progress in growth-arrested bioprocesses.
Serological Diagnosis of Lung Cystic Hydatid Disease Using the Synthetic p176 Peptide
Authors: Santivañez Saul J. , Arias Patricia , Portocarrero Milagrytos , Rodriguez Silvia , Gonzalez Armando E. , Gilman Robert H. , Gavidia Cesar M. , Garcia Hector H.
Published: April 2012

Cystic hydatid disease (CHD) is a worldwide zoonosis caused by the larval stage of the dog tapeworm
Echinococcus granulosus
. Diagnosis is based on imagenological tools (abdominal ultrasound, chest X-rays, or computed tomography [CT] scan). Serological antibody-detecting assays, using diverse native antigens, have been used as a supportive diagnostic tool, but their sensitivities and specificities differ greatly. The use of synthetic peptides as antigens should provide more reliability and allow better assessment and comparison of test formats and case series. The synthetic peptide p176, corresponding to the N-terminal extreme of the subunit of antigen B (AgB8/1), has shown promising performances for diagnosis of CHD. We evaluated the performance of the synthetic peptide p176 for the diagnosis of pulmonary hydatid disease in an enzyme-linked immunosorbent assay (ELISA) format. Sixty-one serum samples from patients with a diagnosis of pulmonary hydatidosis confirmed by surgery and 128 from healthy volunteers were tested. The overall sensitivity and specificity of the p176 ELISA for lung CHD were 78.69% and 96.88%, respectively. On bivariate analysis, positive serum antibody reactions were associated with the presence of complications and with the number of cysts (single/multiple). Only the presence of persistent complications significantly associated with seropositivity on multivariate logistic regression analysis (odds ratio [OR], 9.58; 95% confidence interval [CI], 2.15 to 42.6;
P
= 0.003). The p176 ELISA performs well for the diagnosis of lung CHD and adds an easily reproducible diagnostic assay to the existing diagnostic tools.
Insight into the Antiadhesive Effect of Yeast Wall Protein 1 of Candida albicans
Authors: Granger Bruce L.
Published: April 2012

Ywp1 is a prominent glycosylphosphatidylinositol (GPI)-anchored glycoprotein of the cell wall of
Candida albicans
; it is present in the yeast form of this opportunistic fungal pathogen but absent from filamentous forms and chlamydospores. Yeast cells that lack Ywp1 are more adhesive and form thicker biofilms, implying an antiadhesive activity for Ywp1, with a possible role in yeast dispersal. The antiadhesive effect of Ywp1 is transplantable from yeast to hyphae, as hyphae that are forced to express
YWP1
lose adhesion in an
in vitro
assay. Deletion of the GPI anchor results in loss of Ywp1 to the surrounding medium and reduction of the antiadhesive effect, implying an importance of time-dependent residency in the cell wall. Anchor-negative versions of Ywp1 possessing or lacking a C-terminal green fluorescent protein (GFP) tag were created in
C. albicans
and harvested from culture supernatants; in addition to serving as quantifiable markers for Ywp1 secretion, they revealed that the cleaved 11-kDa propeptide of Ywp1 remains strongly but noncovalently associated with the Ywp1 core. This association is resistant to highly acidic and basic solutions, 8 M urea, and 1% SDS (below 45°C). Above 50°C, SDS dissociates the isolated complex, but even higher temperatures are required to dissociate the propeptide from native Ywp1 that is anchored in a cell wall. This property has permitted detection, for the first time, of orthologs of Ywp1 in other members of the
Candida
clade. The cleaved propeptide, which carries the sole N-glycan of Ywp1, must participate in the antiadhesive effect of Ywp1.
Exposure to Host Ligands Correlates with Colocalization of Gal/GalNAc Lectin Subunits in Lipid Rafts and Phosphatidylinositol (4,5)-Bisphosphate Signaling in Entamoeba histolytica
Authors: Goldston Amanda M. , Powell Rhonda R. , Koushik Amrita B. , Temesvari Lesly A.
Published: April 2012

Entamoeba histolytica
is an intestinal parasite that causes dysentery and liver abscess. Parasite cell surface receptors, such as the Gal/GalNAc lectin, facilitate attachment to host cells and extracellular matrix. The Gal/GalNAc lectin binds to galactose or
N
-acetylgalactosamine residues on host components and is composed of heavy (Hgl), intermediate (Igl), and light (Lgl) subunits. Although Igl is constitutively localized to lipid rafts (cholesterol-rich membrane domains), Hgl and Lgl transiently associate with this compartment in a cholesterol-dependent fashion. In this study, trophozoites were exposed to biologically relevant ligands to determine if ligand binding influences the submembrane distribution of the subunits. Exposure to human red blood cells (hRBCs) or collagen, which are
bona fide
Gal/GalNAc lectin ligands, was correlated with enrichment of Hgl and Lgl in rafts. This enrichment was abrogated in the presence of galactose, suggesting that direct lectin-ligand interactions are necessary to influence subunit location. Using a cell line that is able to attach to, but not phagocytose, hRBCs, it was shown that physical attachment to ligands was not sufficient to induce the enrichment of lectin subunits in rafts. Additionally, the mutant had lower levels of phosphatidylinositol (4,5)-bisphosphate (PIP
2
); PIP
2
loading restored the ability of this mutant to respond to ligands with enrichment of subunits in rafts. Finally, intracellular calcium levels increased upon attachment to collagen; this increase was essential for the enrichment of lectin subunits in rafts. Together, these data provide evidence that ligand-induced enrichment of lectin subunits in rafts may be the first step in a signaling pathway that involves both PIP
2
and calcium signaling.
The
ttpC
Gene Is Contained in Two of Three TonB Systems in the Human Pathogen Vibrio vulnificus, but Only One Is Active in Iron Transport and Virulence
Authors: Kustusch Ryan J. , Kuehl Carole J. , Crosa Jorge H.
Published: April 2012

The TonB system of proteins is required for the energy-dependent active transport of iron-bound substrates across the outer membrane of Gram-negative bacteria. We have identified three TonB systems within the human pathogen
Vibrio vulnificus
. The TonB1 system contains the TonB1, ExbD1, and ExbB1 proteins, whereas both the TtpC2-TonB2 and TtpC3-TonB3 systems contain an additional fourth protein, TtpC. Here we report that TtpC3, although highly related to TtpC2, is inactive in iron transport, whereas TtpC2 is essential for the function of the TtpC2-TonB2 system in
V. vulnificus
. This protein, together with TonB2, is absolutely required for both the uptake of endogenously produced iron-bound siderophores as well as siderophores produced from other organisms. Through complementation we show that
V. vulnificus
is capable of using different TtpC2 proteins from other
Vibrio
species to drive the uptake of multiple siderophores. We have also determined that aerobactin, a common bacterial siderophore involved in virulence of enteric bacteria, can only be brought into the cell using the TtpC2-TonB2 system, indicating an important evolutionary adaptation of TtpC2 and TonB2. Furthermore, in the absence of TonB1, TtpC2 is essential for a fully virulent phenotype as demonstrated using 50% lethal dose (LD
50
) experiments in mice.
Regulation and Evolution of Malonate and Propionate Catabolism in Proteobacteria
Authors: Suvorova I. A. , Ravcheev D. A. , Gelfand M. S.
Published: April 2012

Bacteria catabolize malonate via two pathways, encoded by the
mdc
and
mat
genes. In various bacteria, transcription of these genes is controlled by the GntR family transcription factors (TFs) MatR/MdcY and/or the LysR family transcription factor MdcR. Propionate is metabolized via the methylcitrate pathway, comprising enzymes encoded by the
prp
and
acn
genes. PrpR, the Fis family sigma 54-dependent transcription factor, is known to be a transcriptional activator of the
prp
genes. Here, we report a detailed comparative genomic analysis of malonate and propionate metabolism and its regulation in proteobacteria. We characterize genomic loci and gene regulation and identify binding motifs for four new TFs and also new regulon members, in particular, tripartite ATP-independent periplasmic (TRAP) transporters. We describe restructuring of the genomic loci and regulatory interactions during the evolution of proteobacteria.
SMU.152 Acts as an Immunity Protein for Mutacin IV
Authors: Hossain Mohammad Shahnoor , Biswas Indranil
Published: April 2012

Streptococcus mutans
, a principal causative agent of dental caries, secretes antimicrobial peptides known as mutacins to suppress the growth of competing species to establish a successful colonization.
S. mutans
UA159, a sequenced strain, produces at least two major mutacins, mutacins IV and V. Mutacin IV is a two-peptide mutacin encoded by
nlmAB
genes, which are mapped just upstream of a putative immunity-encoding gene SMU.152. Here we explored the function of SMU.152 as an immunity protein. We observed that overexpression of SMU.152 in two sensitive host strains converted the strains to become immune to mutacin IV. To identify the residues that are important for immunity function, we sequentially deleted residues from the C-terminal region of SMU.152. We observed that deletion of as few as seven amino acids, all of which are highly charged (KRRSKNK), drastically reduced the immunity function of the protein. Furthermore, we identified two other putative immunity proteins, SMU.1909 and SMU.925, which lack the last four charged residues (SKNK) that are present in SMU.152 but contain the KRR residues. Synthetic addition of SKNK residues to either SMU.1909 or SMU.925 to reconstitute the KRRSKNK motif and expressing these constructs in sensitive cells rendered the cells resistant to mutacin IV. We also demonstrated that deletion of Man-PTS system from a sensitive strain made the cells partially resistant to mutacin IV, indicating that the Man-PTS system plays a role in mutacin IV recognition.
Differential Effects of DNA Supercoiling on Chlamydia Early Promoters Correlate with Expression Patterns in Midcycle
Authors: Cheng Eric , Tan Ming
Published: April 2012

Changes in DNA supercoiling levels during the chlamydial developmental cycle have been proposed as a global mechanism to upregulate midcycle genes, but the effects on early genes are not known. We examined the promoters for 10
Chlamydia trachomatis
early genes and found that they could be separated into two subsets based on their responses to DNA supercoiling
in vitro
. Furthermore, the type of supercoiling response correlated with the
in vivo
expression pattern for each early gene. One subset of seven early genes had promoters that were transcribed in a supercoiling-insensitive manner over the physiologic range of supercoiling levels that have been measured in
Chlamydia
.
In vivo
transcripts for these genes were detected at similar levels during early-stage and midstage times. In contrast, a second subset, represented in our study by three early genes, had supercoiling-dependent promoters that were transcribed at higher levels from more-supercoiled templates, which is the response observed for midcycle genes. Genes in this subset were expressed at higher levels at midstage times than at early times
in vivo
. We propose that this second subset represents a novel class of chlamydial developmental genes with features of both early and midcycle genes. We hypothesize that expression of these supercoiling-dependent early genes is upregulated by increased chlamydial supercoiling levels in midcycle via their supercoiling-responsive promoters in a manner similar to that for midcycle genes. Thus, we propose that DNA supercoiling is utilized in
Chlamydia
as a general mechanism to regulate genes in the midstage of the developmental cycle and not just midcycle genes.
The Bacillus subtilis Conjugative Transposon ICEBs1Mobilizes Plasmids Lacking Dedicated Mobilization Functions
Authors: Lee Catherine A. , Thomas Jacob , Grossman Alan D.
Published: April 2012

Integrative and conjugative elements (ICEs, also known as conjugative transposons) are mobile elements that are found integrated in a host genome and can excise and transfer to recipient cells via conjugation. ICEs and conjugative plasmids are found in many bacteria and are important agents of horizontal gene transfer and microbial evolution. Conjugative elements are capable of self-transfer and also capable of mobilizing other DNA elements that are not able to self-transfer. Plasmids that can be mobilized by conjugative elements are generally thought to contain an origin of transfer (oriT), from which mobilization initiates, and to encode a mobilization protein (Mob, a relaxase) that nicks a site inoriTand covalently attaches to the DNA to be transferred. Plasmids that do not have both anoriTand a cognatemobare thought to be nonmobilizable. We found thatBacillus subtiliscarrying the integrative and conjugative element ICEBs1can transfer three different plasmids to recipient bacteria at high frequencies. Strikingly, these plasmids do not have dedicated mobilization-oriTfunctions. Plasmid mobilization required conjugation proteins of ICEBs1, including the putative coupling protein. In contrast, plasmid mobilization did not require the ICEBs1conjugative relaxase or cotransfer of ICEBs1, indicating that the putative coupling protein likely interacts with the plasmid replicative relaxase and directly targets the plasmid DNA to the ICEBs1conjugation apparatus. These results blur the current categorization of mobilizable and nonmobilizable plasmids and indicate that conjugative elements play a role in horizontal gene transfer even more significant than previously recognized.
Roles of Exc Protein and DNA Homology in the CTnDOT Excision Reaction
Authors: Keeton Carolyn M. , Gardner Jeffrey F.
Published: April 2012

Excision from the chromosome is the first step during the transfer of conjugative transposons (CTns) to a recipient. We previously showed that the excision of CTnDOT is more complex than the excision of lambdoid phages and CTns such as Tn
916
. The excision
in vivo
of CTnDOT utilizes four CTnDOT-encoded proteins, IntDOT, Xis2c, Xis2d, and Exc, and a host factor. We previously developed an
in vitro
excision reaction where the recombination sites
attL
and
attR
were located on different plasmids. The reaction was inefficient and did not require Exc, suggesting that the reaction conditions did not mimic
in vivo
conditions. Here, we report the development of an intramolecular excision reaction where the
attL
and
attR
sites are located on the same DNA molecule. We found that Exc stimulates the reaction 3- to 5-fold. The efficiency of the excision reaction was also dependent on the distance between the
attL
and
attR
sites and on the sequences of the overlap regions between the sites of the strand exchanges. Substrates with identical overlap sequences recombined more efficiently than ones with heterologous overlap sequences. This was surprising, because the integration reaction is not sensitive to heterology in the overlap regions of the
attDOT
and
attB
sites.
The Biofilm-Specific Antibiotic Resistance Gene
ndvB
Is Important for Expression of Ethanol Oxidation Genes in Pseudomonas aeruginosa Biofilms
Authors: Beaudoin Trevor , Zhang Li , Hinz Aaron J. , Parr Christopher J. , Mah Thien-Fah
Published: April 2012

Bacteria growing in biofilms are responsible for a large number of persistent infections and are often more resistant to antibiotics than are free-floating bacteria. In a previous study, we identified a
Pseudomonas aeruginosa
gene,
ndvB
, which is important for the formation of periplasmic glucans. We established that these glucans function in biofilm-specific antibiotic resistance by sequestering antibiotic molecules away from their cellular targets. In this study, we investigate another function of
ndvB
in biofilm-specific antibiotic resistance. DNA microarray analysis identified 24 genes that were responsive to the presence of
ndvB
. A subset of 20 genes, including 8 ethanol oxidation genes (
ercS
′,
erbR
,
exaA
,
exaB
,
eraR
,
pqqB
,
pqqC
, and
pqqE
), was highly expressed in wild-type biofilm cells but not in Δ
ndvB
biofilms, while 4 genes displayed the reciprocal expression pattern. Using quantitative real-time PCR, we confirmed the
ndvB
-dependent expression of the ethanol oxidation genes and additionally demonstrated that these genes were more highly expressed in biofilms than in planktonic cultures. Expression of
erbR
in Δ
ndvB
biofilms was restored after the treatment of the biofilm with periplasmic extracts derived from wild-type biofilm cells. Inactivation of ethanol oxidation genes increased the sensitivity of biofilms to tobramycin. Together, these results reveal that
ndvB
affects the expression of multiple genes in biofilms and that ethanol oxidation genes are linked to biofilm-specific antibiotic resistance.
Poor sensitivity of musculoskeletal history in children
Authors: Goff Iain , Rowan Amy , Bateman Belinda Jane , Foster Helen Elizabeth
Published: April 2012

Objectives

To demonstrate the sensitivity of musculoskeletal (MSK) history taking.

Design

Prospective study: consecutive children attending outpatient clinics.

Setting and patients

Paediatric rheumatology clinic (n=45; girls n=28; median age 12 years, range 3–18), acute general paediatric assessment unit (n=50; girls n=21; median age 8 years, range 3–16).

Intervention

Pro forma recording abnormal joint involvement from history taking and then following MSK examination completed by clinicians.

Main outcome measures

Sensitivity of MSK history taking compared with clinical examination.

Results

Paediatric rheumatology clinic: 135 abnormal joints identified in 34 children; 53/135 (39%) by history alone, 82/135 (61%) detected on examination resulting in MSK history sensitivity 53%, specificity 98%. Acute paediatric unit: 29 abnormal joints identified in 17 children; 18/29 identified on history (sensitivity 62%).

Conclusions

MSK history taking failed to identify a large number of abnormal joints which were detected on physical examination, emphasising the need for all joints to be examined as part of a screening examination as a minimum.
Sensitivity and specificity of CT scan and angiogram for ongoing internal bleeding following torso trauma
Authors: Ahmed Nasim , Kassavin Daniel , Kuo Yen-Hong , Biswal Rajiv
Published: April 2012

Background

Occult internal bleeding in the trauma patient which remains undiagnosed and unaddressed has the potential to result in morbidity or mortality. Advancements in CT and angiography have played an integral role in the management of this patient population.

Objective

The purpose of the study was to identify the sensitivity and specificity of CT scan and angiography in detecting ongoing internal bleeding.

Methods

Consecutive patients who sustained torso trauma and subsequently underwent CT scan and angiography were included in this study. Data reviewed included clinical information, CT scan and angiography readings. Extravasations of contrast from CT scan and/or angiogram were considered positive for ongoing internal bleeding.

Results

From January 2002 through July 2007, 113 adult trauma patients sustaining torso trauma underwent CT scan of chest or abdomen followed by angiography. Sixty-six patients were negative for extravasation from either of the tests. Twenty-four of 35 patients had both positive CT scans and angiograms. Eleven patients with positive CT scans did not have bleeding on angiogram. Similarly, 12 out of 36 patients with positive angiograms did not show any extravasation of contrast on CT scan. Both modalities had a specificity of 100% based on clinical definition. The sensitivities of CT scan and angiogram were 74.5% and 76.6%, respectively. They were not significantly different (p=0.95). The negative predictive values for CT and angiogram were 84.6% and 85.7%. They were not significantly different (p=0.95) either. When CT scan was used alone, 25.5% of bleeding patients were missed.

Conclusions

The sensitivity of CT scan and angiography at detecting ongoing bleeding was around 75% across the torso injury spectrum.
Improving documentation in prehospital rapid sequence intubation: investigating the use of a dedicated airway registry form
Authors: Bloomer Roger , Burns Brian J , Ware Sandra
Published: April 2012

Objective

The quality of medical documentation is integral to audit, clinical governance, education, medico-legal aspects and continuity of patient care. This study aims to investigate the introduction of a dedicated ‘Airway Registry Form’ (ARF) on the quality of documentation in prehospital rapid sequence intubation.

Methods

A retrospective review and comparison of 96 cases predating the introduction of the ARF and 90 cases immediately following its introduction were performed.

Results

The introduction of the ARF yielded significant improvement in the recording of selected data points: difficult airway indicators (p<0.0001), Cormack–Lehane grade of laryngoscopy at first attempt (p<0.0001), documentation of confirmation of tracheal intubation with end-tidal carbon dioxide monitoring (p=0.015) and recording of intubator's details (p<0.0001).

Conclusions

This study validates the use of a dedicated ARF for the improvement of documentation and data collection related to prehospital rapid sequence intubation when compared with post-event extraction of data from a generic case-record.
Efficacy of the Disposcope endoscope, a new video laryngoscope, for endotracheal intubation in patients with cervical spine immobilisation by semirigid neck collar: comparison with the Macintosh laryngoscope using a simulation study on a manikin
Authors: Park Sang O , Shin Dong Hyuk , Lee Kyeong Ryong , Hong Dae Young , Kim Eun Jung , Baek Kwang Je
Published: April 2012

Objective

To evaluate whether endotracheal intubation in patients with cervical spine immobilisation by a semirigid neck collar is easier using the Disposcope endoscope (DE), a new video laryngoscope, than with the Macintosh laryngoscope (ML).

Methods

Sixty-eight medical interns who participated in a training programme for endotracheal intubation using the DE and ML were recruited to the randomised crossover trial 1 week after completing the training programme. In the trial, they used both the DE and the ML to perform intubation on a manikin wearing a semirigid neck collar. The time required to view the vocal cords and to complete intubation, successful endotracheal intubation, modified Cormack–Lehane classification (CL grade) and dental injury were recorded and analysed.

Results

The mean (SD) time to view the vocal cords was significantly shorter with the DE than with the ML (10.0 (7.0) vs 20.8 (18.9) s; p<0.0001). There were higher rates of CL grades 1 and 2a (69.1% and 22.1%) using the DE than with the ML (10.3% and 14.7%). All 68 participants had a higher rate of successful endotracheal intubation using the DE than using the ML (68 (100%) vs 47 (69.1%); p<0.0001). It took less time to complete endotracheal intubation with the DE than with the ML (p<0.0001).

Conclusions

In patients with cervical spine immobilisation by a semirigid neck collar, the DE may be a more effective device for endotracheal intubation than the ML.
Risk factors for 48-hours mortality after prehospital treatment of opioid overdose
Authors: Wichmann Sine , Nielsen Søren Loumann , Siersma Volkert Dirk , Rasmussen Lars S
Published: April 2012

Introduction

Opioid overdose is commonly treated by prehospital emergency services and the majority of the patients are discharged immediately after treatment and a short observation period. There is a minor risk for rebound opioid toxicity and other life-threatening conditions might occur after such episodes. The authors describe the short-term outcome and identify risk factors for death within 48 h after prehospital treatment of opioid overdose in Copenhagen, the capital of Denmark.

Methods

Data on all cases of opioid overdose treated by the medical emergency care unit between 1994 and 2003 were recorded prospectively. Risk factors for death within 48 h after initial medical emergency care unit contact were analysed in a multivariable logistic regression analysis.

Results

The authors recorded 4762 episodes of opioid overdose, covering 1967 unique identified patients. A total of 78 patients (8.4%, 95% CI 7.0 to 10.4) died within 48 h in the period 1999–2003, and 85% (66/78) of these had cardiac arrest and died. The authors found age >50 years and overdose during the weekend significantly associated with 48-h mortality. Gender, former episodes of opioid overdose, time of the day, month or year were not significantly associated with increased mortality.

Conclusions

The author found a 48-hours mortality of 8.4%. Advanced age and opioid overdose in the weekends were significant risk factors. Release on scene after treatment was associated with a very small risk.
Are the public ready for organ donation after out of hospital cardiac arrest?
Authors: Bruce Caroline M , Reed Matthew James , MacDougall Margaret
Published: April 2012

Objective

To assess Emergency Department (ED) relatives' and patients' opinions on: (1) discussing organ donation (OD) with relatives soon after ED death after cardiac arrest and (2) acceptability of organ preservation procedures both before and after discussion with relatives.

Methods

Questionnaire study; convenience sample.

Results

200 questionnaires were completed. 37.5% of participants were male subjects; mean age was 40.4 (SD 16.9; range 15–85) years. There was no difference in the number willing to discuss OD after brainstem death in intensive care unit compared with circulatory death in the ED (72% vs 72%; p=0.146). The majority were willing to discuss OD soon after ED death after cardiac arrest (106; 54%). 41 (21%) were not willing and 43 (22%) had no strong views (n=198). Organ preservation procedures (groin tube insertion, continuation of mechanical cardiopulmonary resuscitation and continuation of ventilator) were acceptable to between 48% and 57% of respondents if performed before discussion with family increasing to an acceptability of between 64% and 69% after discussion with family. One in four respondents felt these procedures were not acceptable regardless of the timing of discussion with family and some felt these procedures were more acceptable if the patient was a registered organ donor. 122 (61%) patients wished to donate their organs after death but only 59 (30%) were registered donors.

Conclusions

(1) The majority of patients and their relatives are not averse to OD being discussed shortly after ED death. (2) Organ preservation procedures are acceptable to many. Prior discussion and prior organ donor registration may improve acceptability.
Improving the quality of road injury statistics by using regression models to redistribute ill-defined events
Authors: Shahraz Saeid , Bhalla Kavi , Lozano Rafael , Bartels David , Murray Christopher J L
Published: April 2012

Objective

To test the predictive ability of multinomial regression method in obtaining category of death distribution for cases with unknown/ill-defined mortality codes.

Methods

The authors evaluated the performance of the multinomial regression model by fitting the model to trial datasets from 2004 Mexican vital registration data. To predict category of death, the regression method makes use of explanatory variables, such as gender, age, place of crash, place of residence, education and insurance type. The authors compared the results of a full model regression with those of a reduced model that only contained gender and age as explanatory variables. For this comparison, the authors constructed two forms of data: dummy variable adjustment method and case-wise deleted method. The comparison was made through estimated area under the curve (AUC) for each outcome variable.

Results

The full model significantly outperformed the gender-age (reduced) model using both datasets. In the case-wise deleted method, the AUC was increased from 0.55 to 0.7 for the reduced model and from 0.64 to 0.84 for the full model. Improvement in AUC using the dummy variable adjustment method was less significant.

Conclusions

To predict ill-defined categories of death, adding relevant explanatory variables to gender and age is recommended. Multiple imputations may perform even better than this model especially when significant portion of the data are missing.
Postnatal contraceptive choices among women living with HIV: a decade of experience in a community-based integrated sexual health clinic
Authors: Duncan Sarah , Hawkins Fran , Desmond Noreen
Published: April 2012

Background

Establishing effective postnatal contraception is essential for HIV-seropositive women to avoid the risk of unwanted pregnancy and minimise HIV transmission to HIV-seronegative partners. The authors describe their experience of providing postnatal contraception to HIV-seropositive women who attend a community-based integrated sexual health clinic.

Methods

The authors performed a retrospective case note review of all women who received care for HIV in pregnancy to term at their clinic from September 2000 to October 2010.

Results

A total of 107 pregnancies among 95 women were eligible for review. Attendance for contraceptive advice within 4 weeks of delivery occurred in 82/107 (77%) pregnancies. Depo-Provera® was prescribed in 21 (21/82, 26%) cases; an intrauterine contraceptive was arranged in 22/82 (27%) cases and sterilisation had occurred as part of a Caesarean delivery in 10/82 (12%) cases. In seven women who discontinued antiretroviral therapy at delivery one subdermal implant was fitted and the combined contraceptive pill was prescribed six times. In 17/82 (21%) cases women opted to use condoms alone. Attendance for postpartum contraceptive advice was missed following 21/107 (20%) pregnancies.

Conclusions

Uptake of a second contraceptive method in addition to condoms is high among women who attend clinic for contraceptive advice in the immediate postnatal period. However, 20% of women did not attend and their contraceptive choices remain unknown. These women are at risk of unwanted pregnancy and transmission of HIV to seronegative partners if appropriate contraceptive methods are not re-established postpartum.
COMPONENT SECURITY TESTING APPROACH BASED ON EXTENDED CHEMICAL ABSTRACT MACHINE
Authors: CHEN JINFU , LU YANSHENG , WANG HUANHUAN
Published: April 2012

Unreliable component security hinders the development of component technology. Component security testing is rarely researched with comprehensive focus; several approaches or technologies for detecting vulnerabilities in component security have been proposed, but most are infeasible. A testing approach for component security, which is based on the chemical abstract machine, is proposed for detecting explicit and implicit component security vulnerabilities. We develop an extended chemical abstract machine model, called eCHAM, and generate a state transfer tree and testing sequence for components based on the proposed model. The model can help test the explicit security exceptions of components according to the testing approach of interface fault injection. Condition and state mutation algorithms for identifying implicit security exceptions are also proposed. Vulnerability testing reports are obtained according to the test results. Experiments were conducted in an integration testing platform to verify the applicability of the proposed approach. Results show that the approach is effective and practicable. The proposed approach can detect explicit and implicit security exceptions of components.
Prevention of heart failure in mice by an antiviral agent that inhibits type 5 cardiac adenylyl cyclase
Authors: Iwatsubo Kosaku , Bravo Claudio , Uechi Masami , Baljinnyam Erdene , Nakamura Takashi , Umemura Masanari , Lai Lo , Gao Shumin , Yan Lin , Zhao Xin , Park Misun , Qiu Hongyu , Okumura Satoshi , Iwatsubo Mizuka , Vatner Dorothy E. , Vatner Stephen F. , Ishikawa Yoshihiro
Published: April 2012

Despite numerous discoveries from genetically engineered mice, relatively few have been translated to the bedside, mainly because it is difficult to translate from genes to drugs. This investigation examines an antiviral drug, which also has an action to selectively inhibit type 5 adenylyl cyclase (AC5), a pharmaceutical correlate of the AC5 knockout (KO) model, which exhibits longevity and stress resistance. Our objective was to examine the extent to which pretreatment with this drug, adenine 9-β-d-arabinofuranoside (Ara-A), favorably ameliorates the development of heart failure (HF). Ara-A exhibited selective inhibition for AC5 compared with the other major cardiac AC isoform, AC6, i.e., it reduced AC activity significantly in AC5 transgenic (Tg) mice, but not in AC5KO mice and had little effect in either wild-type or AC6Tg mice. Permanent coronary artery occlusion for 3 wk in C57Bl/6 mice increased mortality and induced HF in survivors, as reflected by reduced cardiac function, while increasing cardiac fibrosis. The AC5 inhibitor Ara-A significantly improved all of these end points and also ameliorated chronic isoproterenol-induced cardiomyopathy. As with the AC5KO mice, Ara-A increased mitogen/extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK) phosphorylation. A MEK inhibitor abolished the beneficial effects of the AC5 inhibitor in the HF model, indicating the involvement of the downstream MEK-ERK pathway of AC5. Our data suggest that pharmacological AC5 inhibition may serve as a new therapeutic approach for HF.
Mast cell deficiency attenuates progression of atherosclerosis and hepatic steatosis in apolipoprotein E-null mice
Authors: Smith Donald D. , Tan Xiaoyu , Raveendran Vineesh V. , Tawfik Ossama , Stechschulte Daniel J. , Dileepan Kottarappat N.
Published: April 2012

Mast cells are important cells of the immune system and are recognized as participants in the pathogenesis of atherosclerosis. In this study, we evaluated the role of mast cells on the progression of atherosclerosis and hepatic steatosis using the apolipoprotein E-deficient ( ApoE−/−) and ApoE−/−/mast cell-deficient ( KitW-sh/W-sh) mouse models maintained on a high-fat diet. The en face analyses of aortas showed a marked reduction in plaque coverage in ApoE−/−/KitW-sh/W-shcompared with ApoE−/−after a 6-mo regimen with no significant change noted after 3 mo. Quantification of intima/media thickness on hematoxylin and eosin-stained histological cross sections of the aortic arch revealed no significant difference between ApoE−/−and ApoE−/−/KitW-sh/W-shmice. The high-fat regimen did not induce atherosclerosis in either KitW-sh/W-shor wild-type mice. Mast cells with indications of degranulation were seen only in the aortic walls and heart of ApoE−/−mice. Compared with ApoE−/−mice, the serum levels of total cholesterol, low-density lipoprotein and high-density lipoprotein were decreased by 50% in ApoE−/−/KitW-sh/W-shmice, whereas no appreciable differences were noted in serum levels of triglycerides or very low density lipoprotein. ApoE−/−/KitW-sh/W-shmice developed significantly less hepatic steatosis than ApoE−/−mice after the 3-mo regimen. The analysis of Th1/Th2/Th17 cytokine profile in the sera revealed significant reduction of interleukin (IL)-6 and IL-10 in ApoE−/−/KitW-sh/W-shmice compared with ApoE−/−mice. The assessment of systemic generation of thromboxane A2(TXA2) and prostaglandin I2(PGI2) revealed significant decrease in the production of PGI2in ApoE−/−/KitW-sh/W-shmice with no change in TXA2. The decrease in PGI2production was found to be associated with reduced levels of cyclooxygenase-2 mRNA in the aortic tissues. A significant reduction in T-lymphocytes and macrophages was noted in the atheromas of the ApoE−/−/KitW-sh/W-shmice. These results demonstrate the direct involvement of mast cells in the progression of atherosclerosis and hepatic steatosis.
Chronic hypoxia induces right heart failure in caveolin-1−/− mice
Authors: Cruz J. Agustin , Bauer Eileen M. , Rodriguez Andres I. , Gangopadhyay Archana , Zeineh Nabil S. , Wang Yinna , Shiva Sruti , Champion Hunter C. , Bauer Philip M.
Published: April 2012

Caveolin-1 (Cav-1)−/− mice develop mild pulmonary hypertension as they age. In this study, we sought to determine the effect of chronic hypoxia, an established model of pulmonary hypertension, on young Cav-1−/− mice with no measurable signs of pulmonary hypertension. Exposure of Cav-1−/− mice to chronic hypoxia resulted in an initial rise in right ventricular (RV) systolic pressure (RVSP) similar to wild-type (WT) mice. By three weeks RVSP decreased in the Cav-1−/− mice, whereas it was maintained in WT mice. The drop in RVSP in Cav-1−/− mice was accompanied by decreased cardiac output, increased RV hypertrophy, RV interstitial fibrosis, decreased RV sarco(endo)plasmic reticulum Ca2+-ATPase 2a mRNA and decreased RV function compared with WT mice. Importantly, minimal differences were noted in pulmonary vascular remodeling between WT and Cav-1−/− mice, and left ventricular function was normal in hypoxic Cav-1−/− mice. Mechanistically, increased endothelial nitric oxide synthase uncoupling and increased tyrosine nitration of protein kinase G were detected in the RV of Cav-1−/− mice. These hemodynamic, histological, and molecular changes were prevented in Cav-1−/− mice expressing an endothelial-specific Cav-1 transgene or by nitric oxide synthase inhibition. These data suggest that, in Cav-1−/− mice, increased oxidative/nitrosative stress due to endothelial nitric oxide synthase uncoupling modifies the response of the RV to pressure overload, accelerating the deterioration of RV function.
Phospholamban ablation in hearts expressing the high affinity SERCA2b isoform normalizes global Ca2+ homeostasis but not Ca2+-dependent hypertrophic signaling
Authors: Louch William E. , Vangheluwe Peter , Bito Virginie , Raeymaekers Luc , Wuytack Frank , Sipido Karin R.
Published: April 2012

Cardiomyocytes from failing hearts exhibit reduced levels of the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA) and/or increased activity of the endogenous SERCA inhibitor phospholamban. The resulting reduction in the Ca2+ affinity of SERCA impairs SR Ca2+ cycling in this condition. We have previously investigated the physiological impact of increasing the Ca2+ affinity of SERCA by substituting SERCA2a with the higher affinity SERCA2b pump. When phospholamban was also ablated, these double knockouts (DKO) exhibited a dramatic reduction in total SERCA levels, severe hypertrophy, and diastolic dysfunction. We presently examined the role of cardiomyocyte Ca2+ homeostasis in both functional and structural remodeling in these hearts. Despite the low SERCA levels in DKO, we observed near-normal Ca2+ homeostasis with rapid Ca2+ reuptake even at high Ca2+ loads and stimulation frequencies. Well-preserved global Ca2+ homeostasis in DKO was paradoxically associated with marked activation of the Ca2+-dependent nuclear factor of activated T-cell-calcineurin pathway known to trigger hypertrophy. No activation of the MAP kinase signaling pathway was detected. These findings suggest that local changes in Ca2+ homeostasis may play an important signaling role in DKO, perhaps due to reduced microdomain Ca2+ buffering by SERCA2b. Furthermore, alterations in global Ca2+ homeostasis can also not explain impaired in vivo diastolic function in DKO. Taken together, our results suggest that normalizing global cardiomyocyte Ca2+ homeostasis does not necessarily protect against hypertrophy and heart failure development and that excessively increasing SERCA Ca2+ affinity may be detrimental.
Differential impact of short periods of rapid atrial pacing on left and right atrial mechanical function
Authors: Weimar Timo , Watanabe Yoshiyuki , Kazui Toshinobu , Lee Urvi S. , Moon Marc R. , Schuessler Richard B. , Damiano Ralph J.
Published: April 2012

Current techniques to describe atrial function are limited by their load dependency and hence do not accurately reflect intrinsic mechanical properties. To assess the impact of atrial fibrillation on atrial function, combined pressure-volume relationships (PVR) measured by conductance catheters were used to evaluate the right (RA) and left (LA) atrium in 12 isoflurane-anesthetized pigs. Biatrial PVR were recorded over a wide range of volumes during transient caval occlusion at baseline sinus rhythm (SR), after onset of rapid atrial pacing (RAP), after 1 h of RAP, after conversion to SR, and after 1 h of recovery. Cardiac output decreased by 16% ( P = 0.008) with onset of RAP. Mean LA and RA pressures increased by 21 and 40% ( P < 0.001), respectively, and remained elevated during the entire recovery period. RA reservoir function increased from 51 to 58% and significantly dropped to 43% after resumption of SR ( P = 0.017). Immediately after RAP, a right shift of LA end-systolic PVR-intercept for end-systolic volume required to generate an atrial end-systolic pressure of 10 mmHg (24.4 ± 4.9 to 28.1 ± 5.2 ml, P = 0.005) indicated impaired contractility compared with baseline. Active LA emptying fraction dropped from 17.6 ± 7.5 to 11.7 ± 3.7% ( P < 0.001), LA stroke volume and ΔP/Δ tmax/P declined by 22% ( P = 0.038 and 0.026, respectively), while there was only a trend to impaired RA systolic function. Stiffness quantified by the ratio of pressure to volume at end-diastole was increased immediately after RAP only in the RA ( P = 0.020), but end-diastolic PVR shifted rightward in both atria ( P = 0.011 LA, P = 0.045 RA). These data suggest that even short periods of RAP have a differential impact on RA and LA function, which was sustained for 1 h after conversion to SR.