1,379 research outputs found
Valproic acid protects against haemorrhagic shock-induced signalling changes via PPARγ activation in an in vitro model.
BACKGROUND AND PURPOSE: Valproic acid (VPA), a widely used epilepsy and bipolar disorder treatment, provides acute protection against haemorrhagic shock-induced mortality in a range of in vivo models through an unknown mechanism. In the liver, this effect occurs with a concomitant protection against a decrease in GSK3β-Ser(9) phosphorylation. Here, we developed an in vitro model to investigate this protective effect of VPA and define a molecular mechanism. EXPERIMENTAL APPROACH: The human hepatocarcinoma cell line (Huh7) was exposed to conditions occurring during haemorrhagic shock (hypoxia, hypercapnia and hypothermia) to investigate the changes in GSK3β-Ser(9) phosphorylation for a 4 h period following treatment with VPA, related congeners, PPAR agonists, antagonists and siRNA. KEY RESULTS: Huh7 cells undergoing combined hypoxia, hypercapnia, and hypothermia reproduced the reduced GSK3β-Ser(9) phosphorylation shown in vivo during haemorrhagic shock, and this change was blocked by VPA. The protective effect occurred through upstream PTEN and Akt signalling, and prevented downstream β-catenin degradation while increasing histone 2/3 acetylation. This effect was reproduced by several VPA-related compounds with known PPARγ agonist activity, independent of histone deacetylase (HDAC) inhibitory activity. Specific pharmacological inhibition (by T0070907) or knockdown of PPARγ blocked the protective effect of VPA against these signalling changes and apoptosis. In addition, specific activation of PPARγ using ciglitazone reproduced the changes induced by VPA in haemorrhagic shock-like conditions. CONCLUSION AND IMPLICATIONS: Changes in GSK3β-Ser(9) phosphorylation in in vivo haemorrhagic shock models can be modelled in vitro, and this has identified a role for PPARγ activation in the protective role of VPA
Modelling human performance within manufacturing systems design:from a theoretical towards a practical framework
Computer-based simulation is frequently used to evaluate the capabilities of proposed manufacturing system designs. Unfortunately, the real systems are often found to perform quite differently from simulation predictions and one possible reason for this is an over-simplistic representation of workers' behaviour within current simulation techniques. The accuracy of design predictions could be improved through a modelling tool that integrates with computer-based simulation and incorporates the factors and relationships that determine workers' performance. This paper explores the viability of developing a similar tool based on our previously published theoretical modelling framework. It focuses on evolving this purely theoretical framework towards a practical modelling tool that can actually be used to expand the capabilities of current simulation techniques. Based on an industrial study, the paper investigates how the theoretical framework works in practice, analyses strengths and weaknesses in its formulation, and proposes developments that can contribute towards enabling human performance modelling in a practical way
Effective silencing of ENaC by siRNA delivered with epithelial-targeted nanocomplexes in human cystic fibrosis cells and in mouse lung
Introduction Loss of the cystic fibrosis transmembrane conductance regulator in cystic fibrosis (CF) leads to hyperabsorption of sodium and fluid from the airway due to upregulation of the epithelial sodium channel (ENaC). Thickened mucus and depleted airway surface liquid (ASL) then lead to impaired mucociliary clearance. ENaC regulation is thus a promising target for CF therapy. Our aim was to develop siRNA nanocomplexes that mediate effective silencing of airway epithelial ENaC in vitro and in vivo with functional correction of epithelial ion and fluid transport.
Methods We investigated translocation of nanocomplexes through mucus and their transfection efficiency in primary CF epithelial cells grown at air–liquid interface (ALI).Short interfering RNA (SiRNA)-mediated silencing was examined by quantitative RT-PCR and western analysis of ENaC. Transepithelial potential (Vt), short circuit current (Isc), ASL depth and ciliary beat frequency (CBF) were measured for functional analysis. Inflammation was analysed by histological analysis of normal mouse lung tissue sections.
Results Nanocomplexes translocated more rapidly than siRNA alone through mucus. Transfections of primary CF epithelial cells with nanocomplexes targeting αENaC siRNA, reduced αENaC and βENaC mRNA by 30%. Transfections reduced Vt, the amiloride-sensitive Isc and mucus protein concentration while increasing ASL depth and CBF to normal levels. A single dose of siRNA in mouse lung silenced ENaC by approximately 30%, which persisted for at least 7 days. Three doses of siRNA increased silencing to approximately 50%.
Conclusion Nanoparticle-mediated delivery of ENaCsiRNA to ALI cultures corrected aspects of the mucociliary defect in human CF cells and offers effective delivery and silencing in vivo
Pharmacokinetics of high-dose oral thiamine hydrochloride in healthy subjects
Background: High dose oral thiamine may have a role in treating diabetes, heart failure, and hypermetabolic states. The purpose of this study was to determine the pharmacokinetic profile of oral thiamine hydrochloride at 100 mg, 500 mg and 1500 mg doses in healthy subjects. Methods: This was a randomized, double-blind, single-dose, 4-way crossover study. Pharmacokinetic measures were calculated. Results: The and values increased nonlinearly between 100 mg and 1500 mg. The slope of the vs dose, as well as the vs dose, plots are steepest at the lowest thiamine doses. Conclusion: Our study demonstrates that high blood levels of thiamine can be achieved rapidly with oral thiamine hydrochloride. Thiamine is absorbed by both an active and nonsaturable passive process
Financial considerations in the conduct of multi-centre randomised controlled trials: evidence from a qualitative study.
National Coordinating Centre for Research Methodology; Medical Research Council, UK Department of Health; Chief Scientist OfficeNot peer reviewedPublisher PD
A cross-sector analysis of human and organisational factors in the deployment of data-driven predictive maintenance
Domains such as utilities, power generation, manufacturing and transport are increasingly turning to data-driven tools for management and maintenance of key assets. Whole ecosystems of sensors and analytical tools can provide complex, predictive views of network asset performance. Much research in this area has looked at the technology to provide both sensing and analysis tools. The reality in the field, however, is that the deployment of these technologies can be problematic due to user issues, such as interpretation of data or embedding within processes, and organisational issues, such as business change to gain value from asset analysis. 13 experts from the field of remote condition monitoring, asset management and predictive analytics across multiple sectors were interviewed to ascertain their experience of supplying data-driven applications. The results of these interviews are summarised as a framework based on a predictive maintenance project lifecycle covering project motivations and conception, design and development, and operation. These results identified critical themes for success around having a target or decision-led, rather than data-led, approach to design; long-term resourcing of the deployment; the complexity of supply chains to provide data-driven solutions and the need to maintain knowledge across the supply chain; the importance of fostering technical competency in end-user organisations; and the importance of a maintenance-driven strategy in the deployment of data-driven asset management. Emerging from these themes are recommendations related to culture, delivery process, resourcing, supply chain collaboration and industry-wide cooperation
Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
We present a review of the interplay between the evolution of circumstellar
disks and the formation of planets, both from the perspective of theoretical
models and dedicated observations. Based on this, we identify and discuss
fundamental questions concerning the formation and evolution of circumstellar
disks and planets which can be addressed in the near future with optical and
infrared long-baseline interferometers. Furthermore, the importance of
complementary observations with long-baseline (sub)millimeter interferometers
and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics
Review"; The final publication is available at http://www.springerlink.co
Threat-sensitive anti-predator defence in precocial wader, the northern lapwing Vanellus vanellus
Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing—observation, approach and usually harassment of a predator—being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing (Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory
Lipopolysaccharide modifies amiloride-sensitive Na+ transport processes across human airway cells: role of mitogen-activated protein kinases ERK 1/2 and 5
Bacterial lipopolysaccharides (LPS) are potent inducers of proinflammatory signaling pathways via the activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK), causing changes in the processes that control lung fluid homeostasis and contributing to the pathogenesis of lung disease. In human H441 airway epithelial cells, incubation of cells with 15 µg ml−1 LPS caused a significant reduction in amiloride-sensitive Isc from 15 ± 2 to 8 ± 2 µA cm−2 (p = 0.01, n = 13) and a shift in IC50 amiloride of currents from 6.8 × 10−7 to 6.4 × 10−6 M. This effect was associated with a decrease in the activity of 5 pS, highly Na+ selective, amiloride-sensitive <1 µM channels (HSC) and an increase in the activity of ∼18 pS, nonselective, amiloride-sensitive >10 µM cation channels (NSC) in the apical membrane. LPS decreased αENaC mRNA and protein abundance, inferring that LPS inhibited αENaC gene expression. This correlated with the decrease in HSC activity, indicating that these channels, but not NSCs, were comprised of at least αENaC protein. LPS increased NF-κB DNA binding activity and phosphorylation of extracellular signal-related kinase (ERK)1/2, but decreased phosphorylation of ERK5 in H441 cells. Pretreatment of monolayers with PD98059 (20 µM) inhibited ERK1/2 phosphorylation, promoted phosphorylation of ERK5, increased αENaC protein abundance, and reversed the effect of LPS on Isc and the shift in amiloride sensitivity. Inhibitors of NF-κB activation were without effect. Taken together, our data indicate that LPS acts via ERK signaling pathways to decrease αENaC transcription, reducing HSC/ENaC channel abundance, activity, and transepithelial Na+ transport in H441 airway epithelial cells
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Molecular and functional correction of a deep intronic splicing mutation in CFTR by CRISPR-Cas9 gene editing.
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CFTR gene. The 10th most common mutation, c.3178-2477C>T (3849+10kb C>T), involves a cryptic, intronic splice site. This mutation was corrected in CF primary cells homozygous for this mutation by delivering pairs of guide RNAs (gRNAs) with Cas9 protein in ribonucleoprotein (RNP) complexes that introduce double-strand breaks to flanking sites to excise the 3849+10kb C>T mutation, followed by DNA repair by the non-homologous end-joining pathway, which functions in all cells of the airway epithelium. RNP complexes were delivered to CF basal epithelial cell by a non-viral, receptor-targeted nanocomplex comprising a formulation of targeting peptides and lipids. Canonical CFTR mRNA splicing was, thus, restored leading to the restoration of CFTR protein expression with concomitant restoration of electrophysiological function in airway epithelial air-liquid interface cultures. Off-target editing was not detected by Sanger sequencing of in silico-selected genomic sites with the highest sequence similarities to the gRNAs, although more sensitive unbiased whole genome sequencing methods would be required for possible translational developments. This approach could potentially be used to correct aberrant splicing signals in several other CF mutations and other genetic disorders where deep-intronic mutations are pathogenic
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