bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of a high-frequency electromagnetic field with a plasma in the presence of a Hall effect
Authors: Imshennik V.S. , Otroshchenko I.V. , Ryabenky V.S. , Osovets S.M. , Khodataev K.V.
Published: January 2011

The penetration of a plasma with finite conductivity and Hall constant by the high-frequency electromagnetic field produced by a travelling wave is considered from the theoretical standpoint, with a view to explaining qualitatively the results of experiments on the containment of a hot plasma with the help of a high-frequency field. A non-linear electrodynamic problem is formulated in the quasi-stationary approximation for a plasma at rest with given constant conductivity and Hall constants – a generalization of the classical skin-effect problem. The problem is solved numerically for the case of cylindrical symmetry and for a wide range of plasma parameters and HF fields. A travelling wave produced by an azimuthal current and propagating over the cylindrical surface in the direction of the system axis is taken as the external source of the HF field. A plasma conductor of fixed radius is located within this surface. On the assumption of sufficiently high plasma conductivity, an effective method of successive approximations is derived; it consists in obtaining alternate numerical solutions of electrodynamic problems that are external and internal to the plasma. The results are used for deriving qualitative and quantitative conclusions regarding the physical characteristics of the interaction between the plasma and the HF field, and for subsequent comparison of theory with experiment.
Collective radiation from plasmas
Authors: Aono O.
Published: January 2011

Radiations from plasmas are caused by binary collisions between dressed particles which are not point particles. The impulse approximation leads to the result by Dupree. The dressed particle includes naturally the ion correlation as well as the electron correlation, while the screened particle of Birmingham et al. excludes the former. Any cut-off procedures of divergent integrals are made unnecessary by considering both the remote and close collisions. In certain cases the radiation is enhanced by collective interactions. An example is given in which the spectrum is expressed in terms of elementary functions.
Self-consistent propagation of an electromagnetic wave and power absorption at the electron gyroresonance in a plasma immersed in a non-uniform magnetic field
Authors: Brambilla M.
Published: January 2011

The self-consistent equation for the propagation of a right-hand polarized electromagnetic wave in a cold plasma immersed in a non-uniform magnetic field is solved exactly under the assumption that the parallel electron velocity v‖ is constant. This equation , which properly takes into account the dissipative component of the induced current, leads to expressions for the reflection, transmission and absorption coefficients which reduce to those obtained by Stix and Budden in the limit v‖ = 0. The reflection coefficient is found to vanish identically, while the absorption is almost complete if the density is sufficiently high.

An approximate solution is then obtained for the case where the non-linear effects in the resonance zone (axial acceleration, relativistic change of mass) cannot be neglected. It is found that these effects can give rise to substantial wave reflection. Thus at high h.f. power the electromagnetic energy is effectively coupled to the plasma only if the density is high enough to reduce the intensity of the electric field in the resonance region to a level such that the linear theory applies.
On the weak Kähler-Ricci flow
Authors: Chen X. , Tian G. , Zhang Z.
Published: January 2011

In this paper, we define and study the Kähler-Ricci flow with initial data not being smooth and discuss some natural applications.
Reconstruction algebras of type 𝐴
Authors: Wemyss Michael
Published: January 2011

We introduce a new class of algebras, called reconstruction algebras, and present some of their basic properties. These non-commutative rings dictate in every way the process of resolving the Cohen-Macaulay singularities

C

2

/

G

\mathbb {C}^2/G

where

G
=

1
r

(
1
,
a
)
≤
G
L
(
2
,

C

)

G=\frac {1}{r}(1,a)\leq GL(2,\mathbb {C})

.
The effect of neuromuscular blockade on mask ventilation
Authors: Warters R. D. , Szabo T. A. , Spinale F. G. , DeSantis S. M. , Reves J. G.
Published: January 2011

We wished to test the hypothesis that neuromuscular blockade facilitates mask ventilation. In order reliably and reproducibly to assess the efficiency of mask ventilation, we developed a novel grading scale (Warters scale), based on attempts to generate a standardised tidal volume. Following induction of general anaesthesia, a blinded anaesthesia provider assessed mask ventilation in 90 patients using our novel grading scale. The non‐blinded anaesthesiologist then randomly administered rocuronium or normal saline. After 2 min, mask ventilation was reassessed by the blinded practitioner. Rocuronium significantly improved ventilation scores on the Warters scale (mean (SD) 2.3 (1.6) vs 1.2 (0.9), p < 0.001). In a subgroup of patients with a baseline Warters scale value of > 3 (i.e. difficult to mask ventilate; n = 14), the ventilation scores also showed significant improvement (4.2 (1.2) vs 1.9 (1.0), p = 0.0002). Saline administration had no effect on ventilation scores. Our data indicate that neuromuscular blockade facilitates mask ventilation. We discuss the implications of this finding for unexpected difficult airway management and for the practice of confirming adequate mask ventilation before the administration of neuromuscular blockade.
Characterization of the PRNP gene locus in Chios dairy sheep and its association with milk production and reproduction traits
Authors: Psifidi A. , Basdagianni Z. , Dovas C. I. , Arsenos G. , Sinapis E. , Papanastassopoulou M. , Banos G.
Published: January 2011

The objective of this study was to examine the prion protein gene locus (PRNP) in Chios sheep. PRNP is linked with scrapie resistance in small ruminants. Here, its impact on milk production (test‐day and total lactation yield) and reproduction (age at first lambing, conception rate at first service, and prolificacy) was assessed. Genotyping at codons 136, 154 and 171 (classical scrapie) and 141 (atypical scrapie) was performed using DNA from milk somatic cells and PCR‐RFLP analysis. A total of 1013 Chios ewes raised in 23 flocks were used. This constituted a random sample of the national breeding population. A total of 15 genotypes and 6 alleles linked to codons 136, 154 and 171 were detected. All animals were homozygous for the leucine allele at codon 141. Linear mixed models were used to assess the impact of PRNP genotypes and alleles on milk production and reproduction traits. The TRQ allele, whose association with such traits was assessed for the first time, had an adverse effect on age at first lambing. All other PRNP alleles, including ARR, which is associated with increased resistance to classical scrapie, had no significant effect on the traits studied. No significant associations of the PRNP genotypes with production and reproduction traits were observed. It was concluded that selection for scrapie‐resistant sheep is not expected to affect the ongoing breeding programme that aims to enhance the milk yield and reproduction of the Chios breed.
α1‐Adrenoceptors and muscarinic receptors in voiding function – binding characteristics of therapeutic agents in relation to the pharmacokinetics
Authors: Yamada Shizuo , Ito Yoshihiko , Tsukada Hideo
Published: January 2011

In vivoandex vivobinding of α1‐adrenoceptor and muscarinic receptors involved in voiding function is reviewed with therapeutic agents (α1‐adrenoceptor antagonists: prazosin, tamsulosin and silodosin; and muscarinic receptor antagonists: oxybutynin, tolterodine, solifenacin, propiverine, imiafenacin and darifenacin) in lower urinary tract symptoms. This approach allows estimation of the inhibition of a well‐characterized selective (standard) radioligand by unlabelled potential drugs or direct measurement of the distribution and receptor binding of a standard radioligand or radiolabelled form of a novel drug. In fact, these studies could be conducted in various tissues from animals pretreated with radioligands and/or unlabelled novel drugs, by conventional radioligand binding assay, radioactivity measurement, autoradiography and positron emission tomography.In vivo and ex vivoreceptor binding with α1‐adrenoceptor antagonists and muscarinic receptor antagonists have been proved to be useful in predicting the potency, organ selectivity and duration of action of drugs in relation to their pharmacokinetics. Such evaluations of drug–receptor binding reveal that adverse effects could be avoided by the use of new α1‐adrenoceptor antagonists and muscarinic receptor antagonists for the treatment of lower urinary tract symptoms. Thus, the comparative analysis of α1‐adrenoceptor and muscarinic receptor binding characteristics in the lower urinary tract and other tissues after systemic administration of therapeutic agents allows the rationale for their pharmacological characteristics from the integrated viewpoint of pharmacokinetics and pharmacodynamics. The current review emphasizes the usefulness ofin vivoandex vivoreceptor binding in the discovery and development of novel drugs for the treatment of not only urinary dysfunction but also other disorders.
Slow‐release oral morphine for opioid maintenance treatment: a systematic review
Authors: Jegu Jeremie , Gallini Adeline , Soler Pauline , Montastruc Jean‐Louis , Lapeyre‐Mestre Maryse
Published: January 2011

This review article summarizes the results of all available clinical trials considering the use of slow‐release oral morphine (SROM) for opioid maintenance treatment (OMT). All studies published up to October 2010 and assessing SROM for OMT in adult patients are included. Three independent reviewers assessed the selected articles using a standardized checklist. Study design, study length and number of subjects included were recorded. Data about retention rate (proportion of participants remaining under maintenance treatment at the end of the study), quality of life, withdrawal symptoms, craving, additional drug consumption, driving capacity and adverse events were collected. We identified 13 articles corresponding to nine clinical trials considering the use of SROM for OMT. Among them, only one was a randomized trial and one was a controlled not randomized trial. All other studies were uncontrolled. Retention rates were good (from 80.6 to 95%) with SROM maintenance, but similar retention rates were obtained with methadone. Most of the studies showed that quality of life, withdrawal symptoms, craving and additional drug consumption improved with SROM. However, there was no comparison with other maintenance drugs. As most of the studies assessing SROM efficacy were uncontrolled, there is no definite evidence that SROM is an effective alternative to methadone for OMT.
Relationships and betrayal among young women: theoretical perspectives on adolescent dating abuse
Authors: Burton Candace W. , Halpern‐Felsher Bonnie , Rankin Sally H. , Rehm Roberta S. , Humphreys Janice C.
Published: January 2011

burton c.w., halpern‐felsher b., rankin s.h., rehm r.s. & humphreys j.c. (2011) Relationships and betrayal among young women: theoretical perspectives on adolescent dating abuse. Journal of Advanced Nursing67(6), 1393–1405.

Aims.  Adolescent dating abuse is not specifically described by any current nursing theory, and this article presents discussion of some existing theories that could inform a nursing theory of adolescent dating abuse. To account for the effects of gender, this discussion is limited to young women.

Background.  Adolescent dating abuse is an important and understudied international issue for nursing. Theoretical frameworks can support development of nursing scholarship for such issues. No single theory yet exists in nursing to explain the experiences and health ramifications of dating abuse among young women.

Data sources.  A summary table of theories is provided. Literature was gathered via database search and bibliographic snowballing from reference lists of relevant articles. Included literature dates from 1982 through 2010.

Discussion.  Theories of relationship formation and function are discussed, including attachment, investment, feminist and gender role conflict theories. Betrayal trauma theory is considered as a mechanism of injury following an abusive dating experience.

Implications for nursing.  Gender, relationship and adolescence combine in a complex developmental moment for young women. To improve nursing care for those at risk for or in the throes of abusive relationships, it is critical to develop specific nursing approaches to understanding these relationships.

Conclusion.  Existing theories related to relationship and traumatic experiences can be combined in the development of a nursing theory of adolescent dating abuse among young women.
Factors affecting nurse practitioner role implementation in Canadian practice settings: an integrative review
Authors: Sangster‐Gormley Esther , Martin‐Misener Ruth , Downe‐Wamboldt Barbara , DiCenso Alba
Published: January 2011

sangster‐gormley e., martin‐misener r., downe‐wamboldt b. & dicenso a. (2011) Factors affecting nurse practitioner role implementation in Canadian practice settings: an integrative review. Journal of Advanced Nursing67(6), 1178–1190.

Aim.  To review the literature about the Canadian experience with nurse practitioner role implementation and identify influencing factors.

Background.  Although nurse practitioners have been in existence for more than 40 years, their integration into healthcare systems has been challenging. While frameworks exist to guide implementation of these roles, clear identification of factors influencing role implementation may inform best practices. Given that Canada has witnessed considerable growth in nurse practitioner positions in the past decade, an exploration of its experience with role implementation is timely.

Data sources.  A review of Canadian literature from 1997 to 2010 was conducted. Electronic databases including CINAHL, Cochrane Database of Systematic Reviews, Health Source: Nursing Academic Edition, Medline, Social Science Index, PubMed, Web of Science and PsychINFO and government and professional organization websites were searched.

Methods.  An integrative review was performed guided by Whittemore and Knafl’s method.

Results.  Ten published studies and two provincial reports were included. Numerous facilitators and barriers to implementation were identified and analysed for themes. Three concepts influencing implementation emerged: involvement, acceptance and intention. Involvement is defined as stakeholders actively participating in the early stages of implementation. Acceptance is recognition and willingness to work with nurse practitioner. Intention relates to how the role is defined.

Conclusion.  This integrative review revealed three factors that influence nurse practitioner role implementation in Canada: involvement, acceptance and intention. Strategies to enhance these factors may inform best practice role implementation processes.
Psychometric validity of the Problem‐Focused Style of Coping scale: in relation to self‐efficacy and life satisfaction among nursing staff in Taiwan
Authors: Chang Yuhsuan
Published: January 2011

chang y. (2011) Psychometric validity of the Problem‐Focused Style of Coping scale: in relation to self‐efficacy and life satisfaction among nursing staff in Taiwan. Journal of Advanced Nursing67(7), 1625–1631.

Aims.  This paper is a report of a study of psychometric properties of the Problem‐Focused Style of Coping‐Chinese version questionnaire.

Background.  Coping with stress is an important topic in the 21th century, which deserves further attention. Although a variety of instruments have emerged to assess an individual’s coping responses to stress, research suggests that numerous problems are associated with the current measurements. Since most coping scales are criticized as lacking valid estimates across occupational samples and cultures, there is an immediate need to develop a reliable and valid coping‐style scale.

Method.  The study used a convenience sample and a sampling frame consisting of 307 nurses from different medical units in two regional hospitals in Taiwan. The data collection period was from May 2009 to June 2009. Exploratory factor analyses and reliability estimates were calculated.

Results.  The factor analysis revealed three coping factors: reflective, suppressive and reactive. All reliability and validity estimates were satisfactory.

Conclusion.  The Problem‐Focused Style of Coping‐Chinese version questionnaire is a valid and reliable measure of nurses’ dispositional coping style and can be used for educational training programmes to enhance nurses’ stress management skills.
Why replication is important in landscape genetics: American black bear in the Rocky Mountains
Authors: SHORT BULL R. A. , CUSHMAN S. A. , MACE R. , CHILTON T. , KENDALL K. C. , LANDGUTH E. L. , SCHWARTZ M.K. , MCKELVEY K. , ALLENDORF FRED W. , LUIKART G.
Published: January 2011

We investigated how landscape features influence gene flow of black bears by testing the relative support for 36 alternative landscape resistance hypotheses, including isolation by distance (IBD) in each of 12 study areas in the north central U.S. Rocky Mountains. The study areas all contained the same basic elements, but differed in extent of forest fragmentation, altitude, variation in elevation and road coverage. In all but one of the study areas, isolation by landscape resistance was more supported than IBD suggesting gene flow is likely influenced by elevation, forest cover, and roads. However, the landscape features influencing gene flow varied among study areas. Using subsets of loci usually gave models with the very similar landscape features influencing gene flow as with all loci, suggesting the landscape features influencing gene flow were correctly identified. To test if the cause of the variability of supported landscape features in study areas resulted from landscape differences among study areas, we conducted a limiting factor analysis. We found that features were supported in landscape models only when the features were highly variable. This is perhaps not surprising but suggests an important cautionary note – that if landscape features are not found to influence gene flow, researchers should not automatically conclude that the features are unimportant to the species’ movement and gene flow. Failure to investigate multiple study areas that have a range of variability in landscape features could cause misleading inferences about which landscape features generally limit gene flow. This could lead to potentially erroneous identification of corridors and barriers if models are transferred between areas with different landscape characteristics.
Assessing the complex architecture of polygenic traits in diverged yeast populations
Authors: CUBILLOS FRANCISCO A. , BILLI ELEONORA , ZÖRGÖ ENIKÖ , PARTS LEOPOLD , FARGIER PATRICK , OMHOLT STIG , BLOMBERG ANDERS , WARRINGER JONAS , LOUIS EDWARD J. , LITI GIANNI
Published: January 2011

Phenotypic variation arising from populations adapting to different niches has a complex underlying genetic architecture. A major challenge in modern biology is to identify the causative variants driving phenotypic variation. Recently, the baker’s yeast, Saccharomyces cerevisiae has emerged as a powerful model for dissecting complex traits. However, past studies using a laboratory strain were unable to reveal the complete architecture of polygenic traits. Here, we present a linkage study using 576 recombinant strains obtained from crosses of isolates representative of the major lineages. The meiotic recombinational landscape appears largely conserved between populations; however, strain‐specific hotspots were also detected. Quantitative measurements of growth in 23 distinct ecologically relevant environments show that our recombinant population recapitulates most of the standing phenotypic variation described in the species. Linkage analysis detected an average of 6.3 distinct QTLs for each condition tested in all crosses, explaining on average 39% of the phenotypic variation. The QTLs detected are not constrained to a small number of loci, and the majority are specific to a single cross‐combination and to a specific environment. Moreover, crosses between strains of similar phenotypes generate greater variation in the offspring, suggesting the presence of many antagonistic alleles and epistatic interactions. We found that subtelomeric regions play a key role in defining individual quantitative variation, emphasizing the importance of the adaptive nature of these regions in natural populations. This set of recombinant strains is a powerful tool for investigating the complex architecture of polygenic traits.
Sedimentology, ichnology and hydrodynamics of strait‐margin, sand and gravel beaches and shorefaces: Juan de Fuca Strait, British Columbia, Canada
Authors: FREY SHANNON E. , DASHTGARD SHAHIN E.
Published: January 2011

On the south‐west coast of Vancouver Island, Canada, sedimentological and ichnological analysis of three beach–shoreface complexes developed along a strait margin was undertaken to quantify process–response relations in straits and to develop a model for strait‐margin beaches. For all three beaches, evidence of tidal processes are expressed best in the lower shoreface and offshore and, to a lesser extent, in the middle shoreface. Tidal currents are dominant offshore, below 18 m water depth (relative to the mean spring high tide), whereas wave processes dominate sediment deposition in the nearshore (intertidal zone to 5 m water depth). From 18 to 5 m water depth, tidal processes decrease in importance relative to wave processes. The relatively high tidal energy in the offshore and lower shoreface is manifest sedimentologically by the dominance of sand, of a similar grain size to the upper shoreface/intertidal zone and, by the prevalence of current‐generated structures (current ripples) oriented parallel to the shoreline. In addition, the offshore and lower shoreface of strait‐bound beach–shoreface complexes are recognized ichnologically by traces typical of the Skolithos Ichnofacies. This situation contrasts to the dominantly horizontal feeding traces characteristic of the Cruziana Ichnofacies that are prevalent in the lower shoreface and offshore of open‐coast (wave‐dominated) beach–shorefaces. These sedimentological and ichnological characteristics reflect tidal influence on sediment deposition; consequently, the term ‘tide‐influenced shoreface’ most accurately describes these depositional environments.
Syngenta ‘RISQ’ test: a novel in‐season method for detecting resistance to post‐emergence ACCase and ALS inhibitor herbicides in grass weeds
Authors: KAUNDUN S S , HUTCHINGS S‐J , DALE R P , BAILLY G C , GLANFIELD P
Published: January 2011

Kaundun SS, Hutchings S‐J, Dale RP, Bailly GC & Glanfield P (2011). Syngenta ‘RISQ’ test: a novel in‐season method for detecting resistance to post‐emergence ACCase and ALS inhibitor herbicides in grass weeds. Weed Research51, 284–293.

This paper describes a novel method for detecting resistance to post‐emergence acetolactate synthase and acetyl CoA carboxylase herbicides in grass weeds. The method relies on seedlings being collected from farmer’s fields and sent for testing to a central laboratory. These seedlings are plated onto agar containing discriminating rates of herbicides and survivorship is recorded after 10 days and compared with standard sensitive and resistant populations. The test has been validated in the glasshouse, growth cabinet and phytotron on Lolium spp. seedlings at the 1–3 leaf stage and has resulted in very low levels of false positives and negatives of resistance. Based on several pre‐determined target site and non‐target site resistant Lolium spp. populations and three commonly used herbicides, clodinafop‐propargyl, pinoxaden and iodosulfuron + mesosulfuron, we demonstrate that the results from the agar‐based seedling assay correlate very well with classical whole‐plant pot tests. The method has been successfully applied to Lolium spp. seedlings collected from two UK fields in 2009 and proved transferable to other grass weeds. As it is applied very early in the season, it provides an opportunity for predicting herbicide efficacy prior to field application and thus allows for an informed choice of herbicide for effective weed control. To distinguish this cost effective, simple and early season bioassay from the many existing ones, we propose to refer to it as the Syngenta ‘Resistance In‐Season Quick’ test.
Childhood acute urticaria in northern and southern Europe shows a similar epidemiological pattern and significant meteorological influences
Authors: Konstantinou George N. , Papadopoulos Nikolaos G. , Tavladaki Theonimfi , Tsekoura Theofani , Tsilimigaki Amalia , Grattan Clive E. H.
Published: January 2011

To cite this article: Konstantinou GN, Papadopoulos NG, Tavladaki T, Tsekoura T, Tsilimigaki A, Grattan CEH. Childhood acute urticaria in northern and southern Europe shows a similar epidemiological pattern and significant meteorological influences. Pediatric Allergy Immunology 2011: 22: 36–42.

Acute urticaria (AU) is a common condition that often presents in childhood. Although there is a general perception of cyclic annual trends in AU, no one has tried to identify any seasonal variation on its prevalence and incidence, associate environmental influences and impute geographic, ethnical, or even genetic features that may contribute to its onset. We aimed to analyze the influence of climate and geographic parameters on annual fluctuation of AU cases referred to the Emergency Departments (EDs) of Norwich (UK) and Heraklion (Crete, Greece), compare all identifiable potential triggers and severity, and calculate the prevalence and incidence of AU. Record‐based data of all children up to 14 yr of age referred to both EDs between June 2005 and May 2007 were examined retrospectively. Demographic characteristics and any potential identifiable triggers of AU were recorded and compared. Poisson’s regression was utilized to examine any influence of meteorological parameters on AU incidence. Edwards’ test for seasonality was applied to identify any significant seasonal trend of the AU incidence within each city. Seven hundred and twenty‐nine AU cases were identified (324 in Norwich and 405 in Heraklio), among 56,624 total referrals (28,931 and 27,693 cases, respectively). Respiratory infections were found to be the most commonly associated potential triggers of AU and food allergens the least. AU cases and incidence rates in both cities were equally distributed during the study period. A non‐significant seasonal trend in AU incidence (October, April–May) was observed in Norwich, in contrast to a significant seasonal pattern (December, February–May) of AU in Heraklio. Temperature was inversely associated with AU incidence, while the statistically significant effect of relative humidity varied. Acute childhood urticaria shows a similar epidemiological pattern in northern and southern Europe regardless of the expected differences in genetic, geographic, and environmental background. Temperature and humidity are correlated with AU incidence. Seasonality of several acute respiratory viral infections, the most prominent associated trigger of AU, coincides with the observed AU seasonality, suggesting a potential linkage. However, this needs to be elucidated from larger epidemiological studies.
Chronic spontaneous urticaria in children: Itching for insight
Authors: Church Martin K. , Weller Karsten , Stock Philippe , Maurer Marcus
Published: January 2011

To cite this article: Church MK, Weller K, Stock P, Maurer M. Chronic spontaneous urticaria in children: Itching for insight. Pediatr Allergy Immunol 2011: 22: 1–8.

While there is increasing information about the pathogenesis and treatment of chronic spontaneous urticaria (csU) in adults, there is little published information about csU in children. Consequently, most of the recommendations contained in current guidelines for the prevention and treatment of csU in infants and children is based on extrapolation of data obtained in adults. To rectify this, this review points out critical gaps in our knowledge and suggests strategies which may help us to improve our understanding of this condition. How common is csU in children? What do we know about its clinical presentation and the presence of useful biomarkers? What are its common underlying causes? What is the course of csU in children? How does csU affect the everyday life of children? What treatment options are available for children? To answer these questions, two separate types of information are required. The first is information about the prevalence of the condition in the community at large and how csU affects the everyday life of both the child‐patient and the parent or carer. Because most csU cases in infants and children do not come to specialists but are treated by general practitioners or by parents using over‐the‐counter medications, these questions may be answered only by general population surveys or schools programmes. The second is clinical information including family history and disease presentation, the presence of biomarkers and comorbidities, objective measures of severity, frequency and duration of exacerbations, the response to therapy and the time to remission. Targeted questionnaires need to be developed and validated for these investigations. This has already begun in Germany with the establishment of the CU‐KID Netzwerk (Email address: cu-kid@charite.de), the aim of which is to identify clinical centres and colleagues who treat children with urticaria and to initiate the information gathering described above.
Formaldehyde induces neurotoxicity to PC12 cells involving inhibition of paraoxonase‐1 expression and activity
Authors: Tang Xiao‐Qing , Ren Yan‐Kai , Chen Rong‐Qian , Zhuang Yuan‐Yuan , Fang Heng‐Rong , Xu Jin‐Hua , Wang Chun‐Yan , Hu Bi
Published: January 2011

1. Formaldehyde (FA) has been found to cause toxicity to neurons. However, its neurotoxic mechanisms have not yet been clarified. Increasing evidence has shown that oxidative damage is one of the most critical effects of formaldehyde exposure. Paraoxonase‐1 (PON‐1) is a pivotal endogenous anti‐oxidant. Thus, we hypothesized that FA‐mediated downregulation of PON1 is associated with its neurotoxicity.

2. In the present work, we used PC12 cells to study the neurotoxicity of FA and explore whether PON‐1 is implicated in FA‐induced neurotoxicity.

3. We found that FA has potent cytotoxic and apoptotic effects on PC12 cells. FA induces an accumulation of intracellular reactive oxygen species along with downregulation of Bcl‐2 expression, as well as increased cytochrome c release. FA significantly suppressed the expression and activity of PON‐1 in PC12 cells. Furthermore, H2S, an endogenous anti‐oxidant gas, antagonizes FA‐induced cytotoxicity as well as 2‐hydroxyquinoline, a specific inhibitor of PON‐1, which also induces cytotoxicity to PC12 cells.

4. The results of the present study provide, for the first time, evidence that the inhibitory effect on PON‐1 expression and activity is involved in the neurotoxicity of FA, and suggest a promising role of PON‐1 as a novel therapeutic strategy for FA‐mediated toxicity.
Renal (pro)renin receptor contributes to development of diabetic kidney disease through transforming growth factor‐β1 – connective tissue growth factor signalling cascade
Authors: Huang Jiqian , Matavelli Luis C , Siragy Helmy M
Published: January 2011

1. Transforming growth factor‐β1 (TGF‐β1) and connective tissue growth factor (CTGF) are expressed in renal glomeruli, and contribute to the development of diabetic nephropathy. Recently, we showed that (pro)renin receptor (PRR) is upregulated in the kidneys of the streptozocin (STZ)‐induced diabetes rat model. We hypothesized that in the presence of hyperglycaemia, increased renal PRR expression contributes to enhanced TGF‐β1–CTGF signalling activity, leading to the development of diabetic kidney disease.

2. In vivo and in vitro studies were carried out in Sprague–Dawley rats and rat mesangial cells (RMC). PRR blockade was achieved in vivo by treating STZ induced diabetes rats with the handle region peptide (HRP) of prorenin and in vitro by HRP or PRR siRNA in RMC. Angiotensin AT1 receptor blockade was achieved by valsartan treatment.

3. Results showed that expression of PRR, TGF‐β1 and CTGF were upregulated in diabetic kidneys and RMC exposed to high glucose. Glucose exposure also induced PRR phosphorylation, a process that was inhibited by HRP, valsartan or PRR siRNA. HRP and valsartan significantly attenuated renal TGF‐β1 and CTGF expression in diabetic animals and high glucose treated RMC. Similar results were observed in high glucose exposed RMC in response to PRR siRNA. TGF‐β receptor blockade decreased CTGF expression in RMC. Combined administration of valsartan and PRR siRNA showed further reduction of TGF‐β1 and CTGF expression in RMC.

4. In conclusion, PRR contributes to kidney disease in diabetes through an enhanced TGF‐β1–CTGF signalling cascade.
Physical forces may cause Hox gene collinearity in the primary and secondary axes of the developing vertebrates
Authors: Papageorgiou Spyros
Published: January 2011

The features of spatial and temporal Hox gene collinearity along the anteroposterior and secondary axes of vertebrate development have been extensively studied. However, the understanding of these features remains problematic. Some genetic engineering experiments were performed and the consequent modifications of the Hoxd gene expressions in the vertebrate limb and trunk were presented. A two‐phases model was proposed to describe the above results but still many data cannot be explained. In the present work a different mechanism is put forward in order to deal with the above experiments. This alternative mechanism (coined biophysical model), is based on the hypothesis that physical forces decondense and ‘loop out’ the chromatin fiber causing the observed Hox gene collinearity phenomena at the early stages of axonal development. The two models are compared in detail. The biophysical model adequately explains the data even in cases where the results are characterized as unexpected. Furthermore, the biophysical model predicts that the Hox gene expressions are entangled in space and time and this coupling is compatible with the data of the early developmental stages. Additional experiments are proposed for a direct test of this model.
Development of Ca2+ signaling mechanisms and cell motility in presumptive ectodermal cells during amphibian gastrulation
Authors: Takano Kazuhiro , Obata Shuichi , Komazaki Shinji , Masumoto Mika , Oinuma Tsutomu , Ito Yuzuru , Ariizumi Takashi , Nakamura Hiroaki , Asashima Makoto
Published: January 2011

This study investigated the development of Ca2+ signaling mechanisms and their role in initiating morphogenetic cell movement in the presumptive ectoderm of Japanese newt (Cynops pyrrhogaster) during gastrulation. Histochemical staining using fluorescently labeled ryanodine and dihydropyridine probes revealed that dihydropyridine receptor (L‐type Ca2+ channels) appeared in stage 12b embryos, while ryanodine receptors were expressed in both stage 11 and 12b embryos. Transmission electron microscopy of stage 12b embryos showed abundant peripheral couplings, which are couplings of the endoplasmic reticulum and cell membrane with an approximate 12 nm gap. Caffeine increased the intracellular free Ca2+ concentration ([Ca2+]i) in presumptive ectodermal cells isolated from both stage 11 and 12b embryos, while (±)‐Bay K 8644 ((±)‐BayK) increased [Ca2+]i in cells isolated from stage 12b embryos, but not in cells isolated from stage 11 embryos. Dantrolene and nifedipine completely inhibited increases in [Ca2+]i after treatment with caffeine and (±)‐BayK, respectively. Caffeine activated the motility of cells isolated from both stage 11 and 12b embryos, but (±)‐BayK only activated the motility of cells isolated from stage 12b embryos. These findings suggested that formation of the Ca2+‐induced Ca2+ release system in presumptive ectodermal cells during gastrulation plays an important role in the initiation and execution of epibolic extension.
Atelocollagen‐mediated systemic administration of myostatin‐targeting siRNA improves muscular atrophy in caveolin‐3‐deficient mice
Authors: Kawakami Emi , Kinouchi Nao , Adachi Taro , Ohsawa Yutaka , Ishimaru Naozumi , Ohuchi Hideyo , Sunada Yoshihide , Hayashi Yoshio , Tanaka Eiji , Noji Sumihare
Published: January 2011

Small interfering RNA (siRNA)‐mediated silencing of gene expression is rapidly becoming a powerful tool for molecular therapy. However, the rapid degradation of siRNAs and their limited duration of activity require efficient delivery methods. Atelocollagen (ATCOL)‐mediated administration of siRNAs is a promising approach to disease treatment, including muscular atrophy. Herein, we report that ATCOL‐mediated systemic administration of a myostatin‐targeting siRNA into a caveolin‐3‐deficient mouse model of limb‐girdle muscular dystrophy 1C (LGMD1C) induced a marked increase in muscle mass and a significant recovery of contractile force. These results provide evidence that ATCOL‐mediated systemic administration of siRNAs may be a powerful therapeutic tool for disease treatment, including muscular atrophy.
Peptidyl‐prolyl cis‐trans isomerase xFKBP1B induces ectopic secondary axis and is involved in eye formation during Xenopus embryogenesis
Authors: Terukina Goro , Yoshida Yoko , Takahashi Nobuhiro
Published: January 2011

Although Xenopus FKBP1A (xFKBP1A) induces an ectopic dorsal axis in Xenopus embryos, involvement of xFKBP1B, a vertebrate paralogue of FKBP1A, in embryogenesis remains undetermined. Here, we demonstrate that xFKBP1B induces ectopic dorsal axis and involves in eye formation of Xenopus embryos. Injection of the xFKBP1B mRNA in ventral blastomeres of 4‐cell stage Xenopus embryos induced a secondary axis and showed multiplier effect to that of xFKBP1A on this when xFKBP1A was co‐injected. In addition, BMP4 and Smad1 mRNAs did not affect the ability of xFKBP1B to induce the ectopic secondary axis when either was co‐injected with xFKBP1B in ventral blastomeres, whereas they downed out that of xFKBP1A, suggesting that xFKBP1A and xFKBP1B induce the ectopic secondary axis through affecting different pathways from each other. On the other hand, the injection of the FKBP1B mRNA in dorsal blastomeres showed eye malformation, and suppressed almost completely the expression of Rx1, Mitf, and Vax2 mRNAs. xFKBP1B was expressed in the dorsal side of the embryo including the eye during embryogenesis at least until stage 46. Injection of morpholino of the xFKBP1B mRNA in dorsal blastomeres induced additional retina or failed to close tapetum nigrum in the ventral side within the optic cap, whereas it did not affect the dorsal organ development. The injection of the morpholino reduced the expression of Xotx2 and Rx1 mRNAs in the eye. These observations suggest that xFKBP1B is a key factor that regulates the expression levels of the genes involved in eye formation during Xenopus embryogenesis.
Role of syndecan‐4 side chains in turkey satellite cell growth and development
Authors: Song Yan , McFarland Douglas C. , Velleman Sandra G.
Published: January 2011

Syndecan‐4 is a cell membrane heparan sulfate proteoglycan that is composed of a core protein and covalently attached glycosaminoglycans (GAG) and N‐linked glycosylated (N‐glycosylated) chains. Syndecan‐4 has been shown to function independent of its GAG chains. Syndecan‐4 may derive its biological function from the N‐glycosylated chains due to the biological role of N‐glycosylated chains in protein folding and cell membrane localization. The objective of the current study was to investigate the role of syndecan‐4 N‐glycosylated chains and the interaction between GAG and N‐glycosylated chains in turkey myogenic satellite cell proliferation, differentiation, and fibroblast growth factor 2 (FGF2) responsiveness. The wild type turkey syndecan‐4 and the syndecan‐4 without GAG chains were cloned into the expression vector pCMS‐EGFP and used as templates to generate syndecan‐4 N‐glycosylated one‐chain and no‐chain mutants with or without GAG chains. The wild type syndecan‐4, all of the syndecan‐4 N‐glycosylated chain mutants were transfected into turkey myogenic satellite cells. Cell proliferation, differentiation, and responsiveness to FGF2 were measured. The overexpression of syndecan‐4 N‐glycosylated mutants with or without GAG chains did not change cell proliferation, differentiation, and responsiveness to FGF2 compared to the wild type syndecan‐4 except that the overexpression of syndecan‐4 N‐glycosylated mutants without GAG chains increased cell proliferation at 48 and 72 h post‐transfection. These data suggest that syndecan‐4 functions in an FGF2‐independent manner, and the N‐glycosylated and GAG chains are required for syndecan‐4 to regulate turkey myogenic satellite cell proliferation, but not differentiation.
From GERD to Barrett's esophagus: Is the pattern in Asia mirroring that in the West?
Authors: Ho Khek Yu
Published: January 2011

Gastroesophageal reflux disease (GERD) is a known predisposing factor for Barrett's esophagus. Amongst individuals with symptomatic GERD, the prevalence of Barrett esophagus is estimated to be more than 10%, and an individual with Barrett's esophagus is more likely than the general population to develop esophageal adenocarcinoma. In Western Europe and North America, incidence of esophageal adenocarcinoma had been on the upward trend for many decades. In comparison, although the prevalence of GERD and reflux esophagitis has increased several fold in some parts of Asia, the prevalence of esophageal adenocarcinoma and Barrett's esophagus remains generally low in the region. Rising incidence of esophageal adenocarcinoma has been observed in regions witnessing increasing prevalence of GERD. If the recent increase in prevalence of GERD in parts of urbanized Asia is any indication of the beginning of an upsurge in the incidence of Barrett's esophagus and associated adenocarcinoma, would we be witnessing a pattern of epidemiological shift mirroring that in the West? Given that more than 90% of Barrett's esophagus in Asian patients is of the short‐segment type, which is reported to have lesser propensity to develop to adenocarcinoma, could the ongoing epidemiologic transition take Asia on the same trail as that which the West has taken? This article will draw on relevant findings from various parts of Asia and take an in‐depth look at prevailing disease trends to see where Asia stands now in the changing epidemiology of GERD, Barrett's esophagus and associated adenocarcinoma.
Regional ventilation distribution determined by electrical impedance tomography: Reproducibility and effects of posture and chest plane
Authors: REIFFERSCHEID FLORIAN , ELKE GUNNAR , PULLETZ SVEN , GAWELCZYK BARBARA , LAUTENSCHLÄGER INGMAR , STEINFATH MARKUS , WEILER NORBERT , FRERICHS INÉZ
Published: January 2011

Background and objective:  Reliable assessment of regional lung ventilation and good reproducibility of electrical impedance tomography (EIT) data are the prerequisites for the future application of EIT in a clinical setting. The aims of our study were to determine (i) the reproducibility of repeated EIT measurements and (ii) the effect of the studied transverse chest plane on ventilation distribution in different postures.

Methods:  Ten healthy adult subjects were studied in three postures on two separate days. EIT and spirometric data were obtained during tidal breathing and slow vital capacity (VC) manoeuvres. EIT data were acquired in two chest planes at 13 scans/s. Reproducibility of EIT findings was assessed by Bland‐Altman analysis and Pearson correlation in 16 regions of interest in each plane. Regional ventilation distribution during tidal breathing and deep expiration was determined as fractional ventilation in four quadrants of the studied chest cross‐sections.

Results:  Our study showed a good reproducibility of EIT measurements repeated after an average time interval of 8 days. Global tidal volumes and VCs determined by spirometry on separate days were not significantly different. Regional ventilation in chest quadrants assessed by EIT was also unaffected. Posture exerted a significant effect on ventilation distribution among the chest quadrants during spontaneous breathing and deep expiration in both planes. The spatial distribution patterns in the two planes were not identical.

Conclusions:  We conclude that regional EIT ventilation findings are reproducible and recommend that the EIT examination location on the chest is carefully chosen especially during repeated measurements and follow‐up.
Combination of endobronchial ultrasound‐guided transbronchial needle aspiration with standard bronchoscopic techniques for the diagnosis of stage I and stage II pulmonary sarcoidosis
Authors: NAVANI NEAL , BOOTH HELEN L. , KOCJAN GABRIJELA , FALZON MARY , CAPITANIO ARRIGO , BROWN JAMES M. , PORTER JOANNA C. , JANES SAM M.
Published: January 2011

Background and objective:  Standard bronchoscopic techniques (transbronchial lung biopsy and endobronchial biopsy) provide a diagnosis in 70% of patients with pulmonary sarcoidosis. Previous data suggest that endobronchial ultrasound‐guided transbronchial needle aspiration (EBUS‐TBNA) has a high sensitivity in patients with sarcoidosis. The feasibility and utility of combining EBUS‐TBNA with standard bronchoscopic techniques is unknown. The aim of this study was to evaluate the feasibility, safety and efficacy of combined EBUS‐TBNA and standard bronchoscopic techniques in patients with suspected sarcoidosis and enlarged mediastinal or hilar lymphadenopathy.

Methods:  Forty consecutive patients with suspected pulmonary sarcoidosis and enlarged mediastinal or hilar lymph nodes (radiographical stage I and stage II) underwent EBUS‐TBNA followed by transbronchial biopsies and endobronchial biopsies under conscious sedation.

Results:  Thirty‐nine out of 40 patients successfully underwent combined EBUS‐TBNA and standard bronchoscopy. Twenty‐seven patients were diagnosed with sarcoidosis, eight had tuberculosis, two had reactive lymphadenopathy, two had lymphoma and one had metastatic adenocarcinoma. In patients with sarcoidosis, the sensitivity of EBUS‐TBNA for detection of non‐caseating granulomas was 85%, compared with a sensitivity of 35% for standard bronchoscopic techniques (P < 0.001). The diagnostic yield of combined EBUS‐TBNA and bronchoscopy was 93% (P < 0.0001).

Conclusions:  Combination of EBUS‐TBNA with standard bronchoscopic techniques is safe and feasible, and optimizes the diagnostic yield in patients with pulmonary sarcoidosis and enlarged intrathoracic lymphadenopathy.