bluuebunny/crossref_metadata_2025 huggingface dataset:
The Conserved DNA-Binding Protein WhiA Is Involved in Cell Division in Bacillus subtilis
Authors: Surdova Katarina , Gamba Pamela , Claessen Dennis , Siersma Tjalling , Jonker Martijs J. , Errington Jeff , Hamoen Leendert W.
Published: October 2013

Bacterial cell division is a highly coordinated process that begins with the polymerization of the tubulin-like protein FtsZ at midcell. FtsZ polymerization is regulated by a set of conserved cell division proteins, including ZapA. However, azapAmutation does not result in a clear phenotype inBacillus subtilis. In this study, we used a synthetic-lethal screen to find genes that become essential when ZapA is mutated. Three transposon insertions were found inyvcL. The deletion ofyvcLin a wild-type background had only a mild effect on growth, but ayvcL zapAdouble mutant is very filamentous and sick. This filamentation is caused by a strong reduction in FtsZ-ring assembly, suggesting that YvcL is involved in an early stage of cell division. YvcL is 25% identical and 50% similar to theStreptomyces coelicolortranscription factor WhiA, which inducesftsZand is required for septation of aerial hyphae during sporulation. Using green fluorescent protein fusions, we show that YvcL localizes at the nucleoid. Surprisingly, transcriptome analyses in combination with a ChIP-on-chip assay gave no indication that YvcL functions as a transcription factor. To gain more insight into the function of YvcL, we searched for suppressors of the filamentous phenotype of ayvcL zapAdouble mutant. Transposon insertions ingtaBandpgcArestored normal cell division of the double mutant. The corresponding proteins have been implicated in the metabolic sensing of cell division. We conclude that YvcL (WhiA) is involved in cell division inB. subtilisthrough an as-yet-unknown mechanism.
Conserved Pyridoxal Protein That Regulates Ile and Val Metabolism
Authors: Ito Tomokazu , Iimori Jumpei , Takayama Sayuri , Moriyama Akihito , Yamauchi Ayako , Hemmi Hisashi , Yoshimura Tohru
Published: October 2013

Escherichia coli
YggS is a member of the highly conserved uncharacterized protein family that binds pyridoxal 5′-phosphate (PLP). To assist with the functional assignment of the YggS family,
in vivo
and
in vitro
analyses were performed using a
yggS
-deficient
E. coli
strain (Δ
yggS
) and a purified form of YggS, respectively. In the stationary phase, the Δ
yggS
strain exhibited a completely different intracellular pool of amino acids and produced a significant amount of
l
-Val in the culture medium. The log-phase Δ
yggS
strain accumulated 2-ketobutyrate, its aminated compound 2-aminobutyrate, and, to a lesser extent,
l
-Val. It also exhibited a 1.3- to 2.6-fold increase in the levels of Ile and Val metabolic enzymes. The fact that similar phenotypes were induced in wild-type
E. coli
by the exogenous addition of 2-ketobutyrate and 2-aminobutyrate indicates that the 2 compounds contribute to the Δ
yggS
phenotypes. We showed that the initial cause of the keto acid imbalance was the reduced availability of coenzyme A (CoA); supplementation with pantothenate, which is a CoA precursor, fully reversed phenotypes conferred by the
yggS
mutation. The plasmid-borne expression of YggS and orthologs from
Bacillus subtilis
,
Saccharomyces cerevisiae
, and humans fully rescued the Δ
yggS
phenotypes. Expression of a mutant YggS lacking PLP-binding ability, however, did not reverse the Δ
yggS
phenotypes. These results demonstrate for the first time that YggS controls Ile and Val metabolism by modulating 2-ketobutyrate and CoA availability. Its function depends on PLP, and it is highly conserved in a wide range species, from bacteria to humans.
Description of a Riboflavin Biosynthetic Gene Variant Prevalent in the Phylum Proteobacteria
Authors: Brutinel Evan D. , Dean Antony M. , Gralnick Jeffrey A.
Published: October 2013

Riboflavin (vitamin B
2
) is the precursor of flavin mononucleotide and flavin adenine dinucleotide, which are cofactors essential for a host of intracellular redox reactions. Microorganisms synthesize flavins
de novo
to fulfill nutritional requirements, but it is becoming increasingly clear that flavins play a wider role in cellular physiology than was previously appreciated. Flavins mediate diverse processes beyond the cytoplasmic membrane, including iron acquisition, extracellular respiration, and interspecies interactions. While investigating the regulation of flavin electron shuttle biosynthesis in the Gram-negative gammaproteobacterium
Shewanella oneidensis
, we discovered that a riboflavin biosynthetic gene (
ribBA
) annotated as encoding a bifunctional 3,4-dihydroxy-2-butanone 4-phosphate (DHBP) synthase/GTP cyclohydrolase II does not possess both functions. The novel gene, renamed
ribBX
here, encodes an amino-terminal DHBP synthase domain. The carboxy-terminal end of RibBX not only lacks GTP cyclohydrolase II activity but also has evolved a different function altogether in
S. oneidensis
, regulating the activity of the DHBP synthase domain. Phylogenetic analysis revealed that the misannotation of
ribBX
as
ribBA
is rampant throughout the phylum
Proteobacteria
(40% of 2,173 annotated
ribBA
genes) and that
ribBX
emerged early in the evolution of this group of microorganisms. We examined the functionality of representative
ribBX
genes from
Beta
-,
Gamma
-, and
Epsilonproteobacteria
and found that, consistent with sequence-based predictions, the encoded GTP cyclohydrolase II domains lack catalytic activity. The persistence of
ribBX
in the genomes of so many phylogenetically divergent bacterial species lends weight to the argument that
ribBX
has evolved a function which lends a selective advantage to the host.
Biochemical Activities of Streptococcus pneumoniae Serotype 2 Capsular Glycosyltransferases and Significance of Suppressor Mutations Affecting the Initiating Glycosyltransferase Cps2E
Authors: James David B. A. , Gupta Kanupriya , Hauser Jocelyn R. , Yother Janet
Published: October 2013

The capsular polysaccharide (CPS) is essential for
Streptococcus pneumoniae
virulence. Its synthesis requires multiple enzymes, and defects that block completion of the pathway can be lethal in the absence of secondary suppressor mutations. In this study, we examined the functions of three capsular glycosyltransferases (Cps2F, Cps2G, and Cps2I) involved in serotype 2 CPS synthesis, whose deletions select for secondary mutations. We demonstrate that Cps2F is a rhamnosyltransferase that catalyzes addition of the third and fourth sugars in the capsule repeat unit, while Cps2G adds the fifth sugar (glucose). Addition of the terminal residue (glucuronic acid) could not be detected; however, activities of the other glycosyltransferases together with bioinformatic analyses suggest that this step is mediated by Cps2I. Most of the secondary suppressor mutations resulting from loss of these enzymes occur in
cps2E
, the gene encoding the initiating glycosyltransferase. Examination of the 69
S. pneumoniae
serotypes containing Cps2E homologues yielded a consensus amino acid sequence for this protein and demonstrated that there is a highly significant association between the residues that are 100% conserved and those altered by suppressor mutations. Cps2E contains an extracytoplasmic loop whose function is unknown. Among our collection of mutants, six contained missense mutations affecting amino acids in the extracytoplasmic loop. These residues are highly conserved among
S. pneumoniae
Cps2E homologues, and mutations therein severely reduced CPS synthesis and Cps2E activity. The critical functions of these amino acids suggest a role for the Cps2E extracytoplasmic loop in initiation, and possibly regulation, of capsule synthesis.
Pseudomonas aeruginosa AlgR Phosphorylation Modulates Rhamnolipid Production and Motility
Authors: Okkotsu Yuta , Tieku Prince , Fitzsimmons Liam F. , Churchill Mair E. , Schurr Michael J.
Published: October 2013

AlgR is a key
Pseudomonas aeruginosa
transcriptional response regulator required for virulence. AlgR activates alginate production and twitching motility but represses the Rhl quorum-sensing (QS) system, including rhamnolipid production. The role of AlgR phosphorylation is enigmatic, since phosphorylated AlgR (AlgR-P) is required for twitching motility through the
fimU
promoter but is not required for the activation of alginate production. In order to examine the role of AlgR phosphorylation
in vivo
, a PAO1
algR
D54E strain (with
algR
encoding a D-to-E change at position 54), which constitutively activates
fimU
transcription and exhibits twitching motility, was created. A corresponding PAO1
algR
D54N strain (with
algR
encoding a D-to-N change at position 54) that does not activate
fimU
or twitching motility was compared to PAO1, PAO1
algR
D54E, PAO1 Δ
algZ
(deletion of the
algZ
[
fimS
] gene, encoding a putative histidine kinase), and PAO1 Δ
algR
for swarming motility, rhamnolipid production, and
rhlA
transcription. PAO1 and PAO1
algR
D54E produced approximately 2-fold-higher levels of rhamnolipids than PAO1
algR
D54N and PAO1 Δ
algZ
, thereby indicating that phosphorylated AlgR is required for normal rhamnolipid production. Examination of purified AlgR, AlgR-P, AlgR D54N, and AlgR D54E showed that AlgR-P and AlgR D54E bound preferentially to the
fimU
and
rhlA
promoters. Additionally, AlgR-P bound specifically to two sites within the
rhlA
promoter that were not bound by unphosphorylated AlgR. Taken together, these results indicate that phosphorylated AlgR-P has increased affinity for the
rhlA
promoter and is required for the coordinate activation of twitching motility, rhamnolipid production, and swarming motility in
P. aeruginosa
.
Cellulose as an Architectural Element in Spatially Structured Escherichia coli Biofilms
Authors: Serra Diego O. , Richter Anja M. , Hengge Regine
Published: October 2013

Morphological form in multicellular aggregates emerges from the interplay of genetic constitution and environmental signals. Bacterial macrocolony biofilms, which form intricate three-dimensional structures, such as large and often radially oriented ridges, concentric rings, and elaborate wrinkles, provide a unique opportunity to understand this interplay of “nature and nurture” in morphogenesis at the molecular level. Macrocolony morphology depends on self-produced extracellular matrix components. In
Escherichia coli
, these are stationary phase-induced amyloid curli fibers and cellulose. While the widely used “domesticated”
E. coli
K-12 laboratory strains are unable to generate cellulose, we could restore cellulose production and macrocolony morphology of
E. coli
K-12 strain W3110 by “repairing” a single chromosomal SNP in the
bcs
operon. Using scanning electron and fluorescence microscopy, cellulose filaments, sheets and nanocomposites with curli fibers were localized
in situ
at cellular resolution within the physiologically two-layered macrocolony biofilms of this “de-domesticated” strain. As an architectural element, cellulose confers cohesion and elasticity, i.e., tissue-like properties that—together with the cell-encasing curli fiber network and geometrical constraints in a growing colony—explain the formation of long and high ridges and elaborate wrinkles of wild-type macrocolonies. In contrast, a biofilm matrix consisting of the curli fiber network only is brittle and breaks into a pattern of concentric dome-shaped rings separated by deep crevices. These studies now set the stage for clarifying how regulatory networks and in particular c-di-GMP signaling operate in the three-dimensional space of highly structured and “tissue-like” bacterial biofilms.
Injury rate and injury pattern among elite World Cup snowboarders: a 6-year cohort study
Authors: Major D H , Steenstrup S E , Bere T , Bahr R , Nordsletten L
Published: October 2013

Background

There is limited knowledge on the injury rate and injury pattern in the different disciplines among elite snowboarders.

Objective

The aim of this study was to describe and compare the injury rate and injury pattern among the different International Ski Federation (Fédération Internationale de Ski, FIS) World Cup (WC) snowboard disciplines.

Methods

We conducted retrospective interviews with FIS WC snowboard athletes at the end of each season in the period 2007–2012, to register all acute injuries sustained during training or competition during the competitive season requiring attention by medical personnel. To calculate the exposure, we obtained information from result lists from the FIS competition database for all WC competitions for each of the interviewed athletes.

Results

We registered a total of 574 injuries among 1432 athletes, accounting for an overall injury rate of 40.1 injuries/100 athlete/season. A total of 171 injuries occurred during the FIS WC competitions, corresponding to 6.4 injuries/1000 runs. During competition, injury risk was highest in snowboard cross with 11.9/1000 runs, followed by 6.3 in halfpipe, 3.6 in big air and 2.8 in parallel giant slalom/parallel slalom (PGS/PSL). Snowboard cross also had the highest risk of severe injuries (>28 days absence). No differences in injury risk were detected between male and female snowboarders. The most commonly injured body part was the knee (17.8%), followed by the shoulder/clavicle (13.4%) and head/face (13.2%). The risk of knee injury (the most common injury type) and head injury was significantly higher in snowboard cross and halfpipe compared to PGS/PSL.

Conclusions

The risk of injuries was higher in snowboard cross than in halfpipe, big air and PGS/PSL. The most commonly injured body part was the knee. Prevention of snowboard injuries among elite snowboarders should focus on knee injuries, severe injuries and snowboard cross athletes.
Leisure-time aerobic physical activity, muscle-strengthening activity and mortality risks among US adults: the NHANES linked mortality study
Authors: Zhao Guixiang , Li Chaoyang , Ford Earl S , Fulton Janet E , Carlson Susan A , Okoro Catherine A , Wen Xiao Jun , Balluz Lina S
Published: October 2013

Background

Regular physical activity elicits multiple health benefits in the prevention and management of chronic diseases. We examined the mortality risks associated with levels of leisure-time aerobic physical activity and muscle-strengthening activity based on the2008 Physical Activity Guidelines for Americansamong US adults.

Methods

We analysed data from the 1999 to 2004 National Health and Nutrition Examination Survey with linked mortality data obtained through 2006. Cox proportional HRs with 95% CIs were estimated to assess risks for all-causes and cardiovascular disease (CVD) mortality associated with aerobic physical activity and muscle-strengthening activity.

Results

Of 10 535 participants, 665 died (233 deaths from CVD) during an average of 4.8-year follow-up. Compared with participants who were physically inactive, the adjusted HR for all-cause mortality was 0.64 (95% CI 0.52 to 0.79) among those who were physically active (engaging in ≥150 min/week of the equivalent moderate-intensity physical activity) and 0.72 (95% CI 0.54 to 0.97) among those who were insufficiently active (engaging in >0 to <150 min/week of the equivalent moderate-intensity physical activity). The adjusted HR for CVD mortality was 0.57 (95% CI 0.34 to 0.97) among participants who were insufficiently active and 0.69 (95% CI 0.43 to 1.12) among those who were physically active. Among adults who were insufficiently active, the adjusted HR for all-cause mortality was 44% lower by engaging in muscle-strengthening activity ≥2 times/week.

Conclusions

Engaging in aerobic physical activity ranging from insufficient activity to meeting the2008 Guidelinesreduces the risk of premature mortality among US adults. Engaging in muscle-strengthening activity ≥2 times/week may provide additional benefits among insufficiently active adults.
When can a professional athlete return to play following scapholunate ligament delayed reconstruction?
Authors: Williams Ashleigh , Ng Chye Yew , Hayton Michael J
Published: October 2013

Background

The aim of this study was to determine the outcomes in relation to return-to-play in professional athletes who had undergone a delayed scapholunate ligament reconstruction.

Methods

We searched our prospectively managed database and identified 15 professional athletes who had undergone the modified Brunelli procedure for scapholunate instability. They were contacted to complete a telephone interview. We established the duration between the operation and return-to-play, the level of competition before and after the procedure and if applicable, reasons for reduction in the level of competition.

Results

Between 2008 and 2011, 15 professional male athletes underwent the modified Brunelli procedure. One was lost to follow-up and 14 athletes (11 rugby, 2 boxing and 1 golf) were contactable. The mean age of the patients was 30 years (range 18–42). The mean follow-up period was 25 months (range 3–43). Eleven of the 14 (79%) athletes returned to play within 4 months of surgery. By the final review, 9 of the 14 (64%) athletes had returned to play at their preinjury level of competition.

Conclusions

A majority (approximately 80%) of professional athletes return to competitive playing within 4 months of undergoing a scapholunate ligament reconstruction. Approximately two-thirds return to play at their preinjury level of competition.
Sports-related extensor carpi ulnaris pathology: a review of functional anatomy, sports injury and management
Authors: Campbell Doug , Campbell Rob , O'Connor Phil , Hawkes Roger
Published: October 2013

The extensor carpi ulnaris (ECU) muscle plays a key role not only in the active movements of wrist extension and ulnar deviation but also in providing stability to the ulnar side of the wrist. Its position relative to the other structures in the wrist changes with forearm pronation and supination. As such, it must be mobile yet stable. The ECU tendon relies on specific stabilising structures to hold it in the correct positions to perform its different functions. These structures can be injured in a variety of different athletic activities such as tennis, golf and rugby league, yet their injury and disruption is predictable when the mechanics of the ECU and the techniques of the sport are understood. The ECU tendon is also vulnerable to tendon pathologies other than instability. It lies subcutaneously and is easily palpated and visualised with diagnostic ultrasound, allowing early diagnosis and management of its specific conditions. Treatment includes rest, splintage and surgery with each modality having specific indications and recognised outcomes. This review described the functional anatomy in relevant sporting situations and explained how problems occur as well as when and how to intervene.
A 3-year survey quantifying the risk of dose escalation of benzodiazepines and congeners to identify risk factors to aid doctors to more rationale prescribing
Authors: Tvete Ingunn Fride , Bjørner Trine , Aursnes Ivar Andreas , Skomedal Tor
Published: October 2013

Objectives

This study investigated and quantified risk factors of dose escalation, as an indication of drug misuse and dependency of benzodiazepines and congeners, among presumably drug naïve patients in the Norwegian drug prescription database, observed over 3 years.

Design

Observational study.

Setting

Prescription database study.

Participants

We defined an excessive user as one redeeming more than two defined daily doses per day in 3 months.

Primary and secondary outcome measures

We examined the risk of excessive use over time and the effect of risk factors through multistate logistic regression and scenarios.

Results

Most of the 81 945 patients had zopiclone or zolpidem as the initial drug (63.8%), followed by diazepam (25.3%), oxazepam (6.1%), nitrazepam/flunitrazepam (2.9%), hydroxyzine/buspirone (1.6%) and alprazolam (0.3%). At any time 23% redeemed prescriptions, about 34% did not redeem any prescriptions beyond any 3-month period and 0.9% ended up as excessive users. Patients previously using drugs, such as opioids, antialcohol or smoke cessation treatment, had a higher risk to become excessive users compared to patients who had not. Patients whose first prescription was for oxazepam or nitrazepam/flunitrazepam had a higher risk of becoming an excessive user compared to those who started with diazepam. A specialist in general practice as the first-time prescriber was associated with a lower risk compared to doctors without specialty.

Conclusions

Most benzodiazepine use occurred according to guidelines. Still, some experienced dose escalation over time, and risk factors were previous use of other psychotropic drugs, long time use, choice of first-time drug and prescriber's specialty. This could incite doctors to have a cessation plan when issuing first-time prescriptions.
Applying ethnography to the study of context in healthcare quality and safety
Authors: Leslie Myles , Paradis Elise , Gropper Michael A , Reeves Scott , Kitto Simon
Published: October 2013

Background

Translating and scaling healthcare quality improvement (QI) and patient safety interventions remains a significant challenge. Context has been identified as a major factor in this. QI and patient safety research have begun to focus on context, with ethnography seen as a promising methodology for understanding the professional, organisational and cultural aspects of context. While ethnography is used to investigate the context of a variety of QI and safety interventions, the challenges inherent in effectively importing a qualitative methodology and its social science practitioners into this work have been largely unexamined.

Method and results

We explain ethnography as a research practice grounded in theory and dependent on observations gathered and interpreted in particular ways. We then review the approach of health services literature to evaluating this sort of qualitative research. Although the study of context is an interest shared by both social scientists and healthcare QI and safety researchers, we identify three key points at which those ‘exporting’ ethnography as a methodology and those ‘importing’ it to deal with QI and safety challenges may diverge. We describe perspectival divergences on the methodology's mission, form and scale. At the level of mission we demonstrate how ethnography has been adapted to a ‘describe and feed back’ role in the service of QI. At the level of form, we show how the long-term embedded observation at the heart of ethnography can be adapted only so far to accommodate QI interests if both data quality and ethical standards are to be upheld. Finally, at the level of scale, we demonstrate one ethnographic study design that balances breadth of exposure with depth of experience in its observations and so generates a particular type of scalable findings.

The effective export of ethnography into QI and safety research requires discussion and negotiation between social scientific and health services research perspectives, as well as creative approaches to producing self-reflexive data that will allow clinicians to understand their own context and so improve their own processes.
External quality assessment ofBRAFmolecular analysis in melanoma
Authors: Deans Zandra C , Wallace Andrew , O'Sullivan Brendan , Purvis Andrew , Camus Suzanne , Fairley Jennifer A , Gonzalez David
Published: October 2013

The availability of BRAF inhibitors has given metastatic melanoma patients an effective new treatment choice and molecular testing to determine the presence or absence of aBRAFcodon 600 mutation is pivotal in the clinical management of these patients. This molecular test must be performed accurately and appropriately to ensure that the patient receives the most suitable treatment in a timely manner. Laboratories have introduced such testing; however, some experience low sample throughput making it critical that an external quality assurance programme is available to help promote a high standard of testing, reporting and provide an educational aspect forBRAFmolecular testing. Laboratories took part in three rounds of external quality assessment (EQA) during a 12-month period giving participants a measure of the accuracy of genotyping, clinical interpretation of the result and experience in testing a range of different samples. Formalin fixed paraffin embedded tissue sections from malignant melanoma patients were distributed to participants forBRAFmolecular testing. The standard of testing was generally high but distribution of a mutation other than the most common, p.(Val600Glu), highlighted concerns with detection or reporting of the presence of rarer mutations. The main issues raised in the interpretation of the results were the importance of clear unambiguous interpretation of the result tailored to the patient and the understanding that the treatment is different from that given to other stratified medicine programmes. The variability in reporting and wide range of methodologies used indicate a continuing need for EQA in this field.
Socioeconomic determinants of haemoglobin levels of African women are less important in areas with more health facilities: a multilevel analysis
Authors: Haverkate Manon , Smits Jeroen , Meijerink Hinta , van der Ven André
Published: October 2013

Background

The prevalence of anaemia in Africa is the highest in the world. Especially women are at risk because of blood loss during menstruation and increased iron requirements during pregnancy. This study examined determinants of the haemoglobin (Hb) level of African women at individual/household, cluster, district, and national level. Special attention was paid to socioeconomic factors and the presence of health facilities.

Methods

Data were derived from Demographic and Health Surveys conducted between 2003 and 2010 in 21 African countries. We included all women aged 15–49 who participated in a women's survey and had a Hb measurement. Multilevel models were used to examine the influence of various factors at different hierarchical levels simultaneously.

Results

104 899 women were included in the study, of which 23.1% were anaemic (Hb<110 g/L). Socioeconomic factors were strongly related to the Hb level of women. Wealth, education, having a job, occupation of the partner, presence of a toilet facility, context educational level and preventive health measures were positively associated with the Hb level. Interaction analysis indicated that socioeconomic differences in the Hb level of women were reduced by the presence of health facilities.

Conclusions

Interventions aimed at improving the Hb level of African women should take socioeconomic and contextual aspects into account. Increasing availability of health facilities might be a tool for reducing socioeconomic differences.
Designing a multimodal feeder network by covering stops with different modes
Authors: Tahoorinia Mohammad Mahdi , Shariat Mohaymany Afshin , Gholami Ali
Published: October 2013

Mass rapid transit requires a high demand to function economically. It is necessary to provide complementary services, such as buses and vans, to increase the required demand. This results in the possibility of providing high performance transit to a wider area. One of the suggested methods is to establish an integrated system of a feeder network. Using such systems provide not only sufficient demand for the main networks but also the possibility of an integrated public transportation system that extends to the entire city. In this paper, we have proposed a method for designing feeder networks that gives multimodal services at each stop simultaneously by assigning the demand to different modes. The demand assignment is based on optimum use of fleet rather than desirability functions. The objective is to minimize the costs of the users, operators, and society. Furthermore, as multimodal network designing is a complex problem, a metaheuristic approach, ant colony optimization, is used. For illustrating and comparing the results, a real example in Mashhad, Iran, is run through 16 different scenarios. The scenarios were designed with different unit costs, and the results have been compared with the latest study. In all of the scenarios, the network costs are lower than those in other methods.
Intrauterine growth restriction is associated with cardiac ultrastructural and gene expression changes related to the energetic metabolism in a rabbit model
Authors: Gonzalez-Tendero Anna , Torre Iratxe , Garcia-Canadilla Patricia , Crispi Fátima , García-García Francisco , Dopazo Joaquin , Bijnens Bart , Gratacós Eduard
Published: October 2013

Intrauterine growth restriction (IUGR) affects 7–10% of pregnancies and is associated with cardiovascular remodeling and dysfunction, which persists into adulthood. The underlying subcellular remodeling and cardiovascular programming events are still poorly documented. Cardiac muscle is central in the fetal adaptive mechanism to IUGR given its high energetic demands. The energetic homeostasis depends on the correct interaction of several molecular pathways and the adequate arrangement of intracellular energetic units (ICEUs), where mitochondria interact with the contractile machinery and the main cardiac ATPases to enable a quick and efficient energy transfer. We studied subcellular cardiac adaptations to IUGR in an experimental rabbit model. We evaluated the ultrastructure of ICEUs with transmission electron microscopy and observed an altered spatial arrangement in IUGR, with significant increases in cytosolic space between mitochondria and myofilaments. A global decrease of mitochondrial density was also observed. In addition, we conducted a global gene expression profile by advanced bioinformatics tools to assess the expression of genes involved in the cardiomyocyte energetic metabolism and identified four gene modules with a coordinated over-representation in IUGR: oxygen homeostasis (GO: 0032364), mitochondrial respiratory chain complex I (GO:0005747), oxidative phosphorylation (GO: 0006119), and NADH dehydrogenase activity (GO:0003954). These findings might contribute to changes in energetic homeostasis in IUGR. The potential persistence and role of these changes in long-term cardiovascular programming deserves further investigation.
Central control of cardiovascular function during sleep
Authors: Silvani Alessandro , Dampney Roger A. L.
Published: October 2013

There is increasing evidence that cardiovascular control during sleep is relevant for cardiovascular risk. This evidence warrants increased experimental efforts to understand the physiological mechanisms of such control. This review summarizes current knowledge on autonomic features of sleep states [non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS)] and proposes some testable hypotheses concerning the underlying neural circuits. The physiological reduction of blood pressure (BP) during the night (BP dipping phenomenon) is mainly caused by generalized cardiovascular deactivation and baroreflex resetting during NREMS, which, in turn, are primarily a consequence of central autonomic commands. Central commands during NREMS may involve the hypothalamic ventrolateral preoptic area, central thermoregulatory and central baroreflex pathways, and command neurons in the pons and midbrain. During REMS, opposing changes in vascular resistance in different regional beds have the net effect of increasing BP compared with that of NREMS. In addition, there are transient increases in BP and baroreflex suppression associated with bursts of brain and skeletal muscle activity during REMS. These effects are also primarily a consequence of central autonomic commands, which may involve the midbrain periaqueductal gray, the sublaterodorsal and peduncular pontine nuclei, and the vestibular and raphe obscurus medullary nuclei. A key role in permitting physiological changes in BP during sleep may be played by orexin peptides released by hypothalamic neurons, which target the postulated neural pathways of central autonomic commands during NREMS and REMS. Experimental verification of these hypotheses may help reveal which central neural pathways and mechanisms are most essential for sleep-related changes in cardiovascular function.
Chronic intermittent hypoxia increases sympathetic control of blood pressure: role of neuronal activity in the hypothalamic paraventricular nucleus
Authors: Sharpe Amanda L. , Calderon Alfredo S. , Andrade Mary Ann , Cunningham J. Thomas , Mifflin Steven W. , Toney Glenn M.
Published: October 2013

Like humans with sleep apnea, rats exposed to chronic intermittent hypoxia (CIH) experience arterial hypoxemias and develop hypertension characterized by exaggerated sympathetic nerve activity (SNA). To gain insights into the poorly understood mechanisms that initiate sleep apnea/CIH-associated hypertension, experiments were performed in rats exposed to CIH for only 7 days. Compared with sham-treated normoxic control rats, CIH-exposed rats ( n = 8 rats/group) had significantly increased hematocrit ( P < 0.001) and mean arterial pressure (MAP; P < 0.05). Blockade of ganglionic transmission caused a significantly ( P < 0.05) greater reduction of MAP in rats exposed to CIH than control rats ( n = 8 rats/group), indicating a greater contribution of SNA in the support of MAP even at this early stage of CIH hypertension. Chemical inhibition of neuronal discharge in the hypothalamic paraventricular nucleus (PVN) (100 pmol muscimol) had no effect on renal SNA but reduced lumbar SNA ( P < 0.005) and MAP ( P < 0.05) more in CIH-exposed rats ( n = 8) than control rats ( n = 7), indicating that CIH increased the contribution of PVN neuronal activity in the support of lumbar SNA and MAP. Because CIH activates brain regions controlling body fluid homeostasis, the effects of internal carotid artery injection of hypertonic saline were tested and determined to increase lumbar SNA more ( P < 0.05) in CIH-exposed rats than in control rats ( n = 9 rats/group). We conclude that neurogenic mechanisms are activated early in the development of CIH hypertension such that elevated MAP relies on increased sympathetic tonus and ongoing PVN neuronal activity. The increased sensitivity of Na+/osmosensitive circuitry in CIH-exposed rats suggests that early neuroadaptive responses among body fluid regulatory neurons could contribute to the initiation of CIH hypertension.
Estradiol activates epithelial sodium channels in rat alveolar cells through the G protein-coupled estrogen receptor
Authors: Greenlee Megan M. , Mitzelfelt Jeremiah D. , Yu Ling , Yue Qiang , Duke Billie Jeanne , Harrell Constance S. , Neigh Gretchen N. , Eaton Douglas C.
Published: October 2013

Female sex predisposes individuals to poorer outcomes during respiratory disorders like cystic fibrosis and influenza-associated pneumonia. A common link between these disorders is dysregulation of alveolar fluid clearance via disruption of epithelial sodium channel (ENaC) activity. Recent evidence suggests that female sex hormones directly regulate expression and activity of alveolar ENaC. In our study, we identified the mechanism by which estradiol (E2) or progesterone (P4) independently regulates alveolar ENaC. Using cell-attached patch clamp, we measured ENaC single-channel activity in a rat alveolar cell line (L2) in response to overnight exposure to either E2 or P4. In contrast to P4, E2 increased ENaC channel activity ( NPo) through an increase in channel open probability ( Po) and an increased number of patches with observable channel activity. Apical plasma membrane abundance of the ENaC α-subunit (αENaC) more than doubled in response to E2 as determined by cell surface biotinylation. αENaC membrane abundance was approximately threefold greater in lungs from female rats in proestrus, when serum E2 is greatest, compared with diestrus, when it is lowest. Our results also revealed a significant role for the G protein-coupled estrogen receptor (Gper) to mediate E2's effects on ENaC. Overall, our results demonstrate that E2 signaling through Gper selectively activates alveolar ENaC through an effect on channel gating and channel density, the latter via greater trafficking of channels to the plasma membrane. The results presented herein implicate E2-mediated regulation of alveolar sodium channels in the sex differences observed in the pathogenesis of several pulmonary diseases.
NF-κB pathway is involved in CRP-induced effects on pulmonary arterial endothelial cells in chronic thromboembolic pulmonary hypertension
Authors: Wynants Marijke , Vengethasamy Leanda , Ronisz Alicja , Meyns Bart , Delcroix Marion , Quarck Rozenn
Published: October 2013

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombofibrotic obstruction of proximal pulmonary arteries. The cellular and molecular mechanisms underlying the pathogenesis remain incompletely understood, although we recently evidenced the potential involvement of the inflammatory marker C-reactive protein (CRP). We aimed to investigate the intracellular mechanisms induced by CRP in proximal pulmonary arterial endothelial cells (PAEC). PAEC were isolated from vascular material obtained during pulmonary endarterectomy. RNA was extracted from CRP-stimulated PAEC, and first-stand cDNA was generated. A RT2profiler PCR Array was used to evaluate the expression of 84 key genes related to NF-κB-mediated signal transduction. CRP-induced NF-κB activation was studied. The effects of pyrrolidine-dithio-carbamate ammonium (PDTC), an inhibitor of the NF-κB pathway, were investigated on CRP-induced adhesion of monocytes to PAEC, adhesion molecule expression, endothelin-1 (ET-1), interleukin-6 (IL-6), and von Willebrand factor (vWF) secretion. Compared with nonstimulated PAEC, serotonin receptor 2B was downregulated by 25%, inhibitor of NF-κB kinase subunit epsilon (IKBKE) by 30%, and toll-like receptor-4 and -6 by 18 and 39%, respectively, in CRP-stimulated PAEC. The transcription factor FOS was threefold upregulated. CRP induced RelA/NF-κBp65 phosphorylation. PDTC dose dependently inhibited the adhesion of monocytes to CRP-stimulated PAEC. PDTC also inhibited the CRP-induced expression of ICAM-1 at the surface of PAEC. PDTC impaired the secretion of ET-1 by 18% and tended to inhibit the secretion of IL-6 by CRP-stimulated PAEC by 46%. PDTC did not inhibit the CRP-induced secretion of vWF. These results suggest an involvement of the NF-κB pathway in mediating different effects of CRP on proximal CTEPH-PAEC.
Flagellin/TLR5 signaling potentiates airway serous secretion from swine tracheal submucosal glands
Authors: Muramatsu Soshi , Tamada Tsutomu , Nara Masayuki , Murakami Koji , Kikuchi Toshiaki , Kanehira Masahiko , Maruyama Yoshio , Ebina Masahito , Nukiwa Toshihiro , Ichinose Masakazu
Published: October 2013

Airway serous secretion is essential for the maintenance of mucociliary transport in airway mucosa, which is responsible for the upregulation of mucosal immunity. Although there are many articles concerning the importance of Toll-like receptors (TLRs) in airway immune systems, the direct relationship between TLRs and airway serous secretion has not been well investigated. Here, we focused on whether TLR5 ligand flagellin, which is one of the components of Pseudomonas aeruginosa, is involved in the upregulation of airway serous secretion. Freshly isolated swine tracheal submucosal gland cells were prepared, and the standard patch-clamp technique was applied for measurements of the whole cell ionic responses of these cells. Flagellin showed potentiating effects on these oscillatory currents induced by physiologically relevant low doses of acetylcholine (ACh) in a dose-dependent manner. These potentiating effects were TLR5 dependent but TLR4 independent. Both nitric oxide (NO) synthase inhibitors and cGMP-dependent protein kinase (cGK) inhibitors abolished these flagellin-induced potentiating effects. Furthermore, TLR5 was abundantly expressed on tracheal submucosal glands. Flagellin/TLR5 signaling further accelerated the intracellular NO synthesis induced by ACh. These findings suggest that TLR5 takes part in the airway mucosal defense systems as a unique endogenous potentiator of airway serous secretions and that NO/cGMP/cGK signaling is involved in this rapid potentiation by TLR5 signaling.
Genetic deletion of IL-17A reduces cigarette smoke-induced inflammation and alveolar type II cell apoptosis
Authors: Chang Ying , Al-Alwan Laila , Audusseau Severine , Chouiali Fazila , Carlevaro-Fita Juna , Iwakura Yoichiro , Baglole Carolyn J. , Eidelman David H. , Hamid Qutayba
Published: October 2013

Chronic obstructive pulmonary disease (COPD) is an inflammatory disorder marked by relative resistance to steroids. Inflammation and apoptosis have been suggested to be important mechanisms for COPD. Interleukin (IL)-17 superfamily has been associated with chronic inflammation and diminished responses to steroids. It is reasonable to consider that IL-17 may play a role in the pathogenesis of COPD. In this study, we examined IL-17 expression in mice exposed to cigarette smoke (CS) and investigated the contribution of IL-17 to CS-induced inflammation and alveolar cell apoptosis in IL-17−/−mice. After exposing wild-type and IL-17−/−mice to mainstream CS for 4 wk, IL-17A, but not IL-17F, expression was increased in mice upon CS exposure. Neutrophil infiltration in the lungs of IL-17−/−mice was significantly decreased. In IL-17−/−mice, there is reduced expression of IL-6, macrophage inflammatory protein-2, and matrix metalloproteinase-12 compared with wild-type mice after CS exposure. The number of apoptotic type II alveolar cells was significantly increased in CS-exposed wild-type mice but not in IL-17−/−mice. The effect of IL-17A on type II alveolar cell apoptosis was confirmed in vitro through either addition of IL-17A or transient knockdown of IL-17A by small-interfering RNA transfection in type II alveolar cells. These findings suggest that IL-17A plays an important role in the inflammatory response to CS exposure through increased multiple inflammatory mediators. Moreover, IL-17 may also contribute to type II alveolar cell apoptosis. This study opens a new option in targeting IL-17A to modulate inflammatory response to CS and may be the bases for new therapy for COPD.
Hyperglycemia impedes lung bacterial clearance in a murine model of cystic fibrosis-related diabetes
Authors: Hunt William R. , Zughaier Susu M. , Guentert Dana E. , Shenep Melissa A. , Koval Michael , McCarty Nael A. , Hansen Jason M.
Published: October 2013

Cystic fibrosis-related diabetes (CFRD) is the most common comorbidity associated with cystic fibrosis (CF), impacting more than half of patients over age 30. CFRD is clinically significant, portending accelerated decline in lung function, more frequent pulmonary exacerbations, and increased mortality. Despite the profound morbidity associated with CFRD, little is known about the underlying CFRD-related pulmonary pathology. Our aim was to develop a murine model of CFRD to explore the hypothesis that elevated glucose in CFRD is associated with reduced lung bacterial clearance. A diabetic phenotype was induced in gut-corrected CF transmembrane conductance regulator (CFTR) knockout mice (CFKO) and their CFTR-expressing wild-type littermates (WT) utilizing streptozotocin. Mice were subsequently challenged with an intratracheal inoculation of Pseudomonas aeruginosa (PAO1) (75 μl of 1–5 × 106cfu/ml) for 18 h. Bronchoalveolar lavage fluid was collected for glucose concentration and cell counts. A portion of the lung was homogenized and cultured as a measure of the remaining viable PAO1 inoculum. Diabetic mice had increased airway glucose compared with nondiabetic mice. The ability to clear bacteria from the lung was significantly reduced in diabetic WT mice and control CFKO mice. Critically, bacterial clearance by diabetic CFKO mice was significantly more diminished compared with nondiabetic CFKO mice, despite an even more robust recruitment of neutrophils to the airways. This finding that CFRD mice boast an exaggerated, but less effective, inflammatory cell response to intratracheal PAO1 challenge presents a novel and useful murine model to help identify therapeutic strategies that promote bacterial clearance in CFRD.
The collaboration of Antoine and Marie-Anne Lavoisier and the first measurements of human oxygen consumption
Authors: West John B.
Published: October 2013

Antoine Lavoisier (1743–1794) was one of the most eminent scientists of the late 18th century. He is often referred to as the father of chemistry, in part because of his book Elementary Treatise on Chemistry. In addition he was a major figure in respiratory physiology, being the first person to recognize the true nature of oxygen, elucidating the similarities between respiration and combustion, and making the first measurements of human oxygen consumption under various conditions. Less well known are the contributions made by his wife, Marie-Anne Lavoisier. However, she was responsible for drawings of the experiments on oxygen consumption when the French revolution was imminent. These are of great interest because written descriptions are not available. Possible interpretations of the experiments are given here. In addition, her translations from English to French of papers by Priestley and others were critical in Lavoisier's demolition of the erroneous phlogiston theory. She also provided the engravings for her husband's textbook, thus documenting the extensive new equipment that he developed. In addition she undertook editorial work, for example in preparing his posthumous memoirs. The scientific collaboration of this husband-wife team is perhaps unique among the giants of respiratory physiology.
CFD Modeling of Particulates Erosive Effect on a Commercial Scale Pipeline Bend
Authors: Abdolkarimi Vahid , Mohammadikhah Rasool
Published: October 2013

The computational fluid dynamics modeling of solid particles hydrodynamic based on the Lagrangian framework for diluted solid-gas flow through 90° gas pipeline bend is carried out to discover the effect of particles size distribution on particles flow pattern and their erosive effect on the bend. Particles size distribution has been obtained experimentally by measuring the sizes of solid particles that are flowing through the gas pipelines of Aghajari gas booster station. Also the erosion rate at the outer wall of the bend is predicted. The pipeline bend under study has a pipe diameter of 56 inches and ratios of the bend radius of the curvature to the pipeline diameter of 1.5. For the validation of computational model, firstly, the computational modeling is performed for a published experimental solid-gas flow data. The computational results include radial gas velocity and radial particle velocity profiles on planes which are at different angles through the bend. The comparison between the predicted numerical results and similar experimental data proves that the predictions of the computational model are acceptable. Finally, the particles' size distributions on each plane through the bend and the erosion rate on the outer wall of the bend have been obtained. The maximum rate of erosion is found to be 3.2 nm/s, occurring between 40 and 65° of the bend.