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Find video protocols related to scientific articles indexed in Pubmed.
Conformation determines the seeding potencies of native and recombinant tau aggregates.
J. Biol. Chem.
PUBLISHED: 11-20-2014
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Intracellular tau inclusions are a pathological hallmark of several neurodegenerative diseases, collectively known as the tauopathies. They include Alzheimer's disease, tangle-only dementia, Pick's disease, argyrophilic grain disease, chronic traumatic encephalopathy, progressive supranuclear palsy and corticobasal degeneration. Tau pathology appears to spread through intercellular propagation, requiring the formation of assembled ?prion-like?species. Several cell and animal models have been described that recapitulate aspects of this phenomenon. However, the molecular characteristics of seed-competent tau remain unclear. Here, we have used a cell model to understand the relationships between tau structure/phosphorylation and seeding by aggregated tau species from the brains of mice transgenic for human mutant P301S tau and full-length aggregated recombinant P301S tau. Deletion of motifs 275VQIINK280 and 306VQIVYK311 abolished the seeding activity of recombinant full-length tau, suggesting that its aggregation was necessary for seeding. We describe conformational differences between native and synthetic tau aggregates that may account for the higher seeding activity of native assembled tau. When added to aggregated tau seeds from the brains of mice transgenic for P301S tau, soluble recombinant tau aggregated and acquired the molecular properties of aggregated tau from transgenic mouse brain. We show that seeding is conferred by aggregated tau that enters cells through macropinocytosis and seeds the assembly of endogenous tau into filaments.
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Mapping Electroactivity at Individual Catalytic Nanostructures using High Resolution SECM-SICM.
Anal. Chem.
PUBLISHED: 11-18-2014
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Combined scanning electrochemical-scanning ion conductance microcopy (SECM-SICM) has been used to map the electroactivity of surfaces decorated with individual features at the 100 -150 nm scale. Dual channel capillary probes consisting of an open SICM barrel and a solid carbon SECM electrode enabled correlation of surface activity with accurate topographical information. Measurements were validated by approach curve analysis and imaging of model systems in feedback and substrate generation-tip collection modes, and then applied to the examination of two nanostructured test substrates: Firstly, electronically isolated gold nanodisk arrays were imaged using a simple electrochemical redox mediator, in which a clear positive feedback was observed at the SECM electrode and the topographical channel compared well with AFM imaging. Secondly, platinum nanosphere ensembles were mapped using platinum-modified carbon probes to detect oxygen consumption in a redox competition mode, demonstrating the means to study electrocatalytic processes at individual nanoparticles. This work demonstrates the value of high-resolution SECM-SICM for low-current amperometric imaging of nanosystems, and highlights its potential for the quantitative measurement of electrokinetics at the single particle level.
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Early-onset lymphoproliferation and autoimmunity caused by germline STAT3 gain-of-function mutations.
Blood
PUBLISHED: 11-01-2014
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Germline, loss-of-function mutations in the transcription factor STAT3 cause immunodeficiency, while somatic, gain-of-function mutations in STAT3 are associated with large granular lymphocytic leukemic, myelodysplastic syndrome, and aplastic anemia. Recently, germline mutations in STAT3 have also been associated with autoimmune disease. Here we report thirteen individuals from ten families with lymphoproliferation and early-onset, solid organ autoimmunity associated with nine different germline, heterozygous mutations in STAT3. Patients exhibited a variety of clinical features, with most having lymphadenopathy, autoimmune cytopenias, multi-organ autoimmunity (lung, gastrointestinal, hepatic, and/or endocrine dysfunction), infections and short stature. Functional analyses demonstrate that these mutations confer a gain-of-function in STAT3 leading to secondary defects in STAT5 and STAT1 phosphorylation and the regulatory T cell compartment. Treatment targeting a cytokine pathway that signals through STAT3 lead to clinical improvement in one patient, suggesting a potential therapeutic option for such patients. These results suggest that there is a broad range of autoimmunity caused by germline STAT3 gain-of-function mutations, and that hematologic autoimmunity is a major component of this newly-described disorder. Some patients for this study were enrolled in a trial registered at ClinicalTrials.gov #NCT00001350.
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Impact of childhood anthropometry trends on adult lung function.
Chest
PUBLISHED: 10-24-2014
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Background:Poor fetal growth rate is associated with lower respiratory function; however there is limited understanding of the impact of growth trends and body mass index(BMI) during childhood on adult respiratory function. Methods:The present study data are from the Mater-University of Queensland Study of Pregnancy birth cohort. Prospective data were available from 1740 young adults who performed standard spirometry at 21 years and birth weight, and weight, height and BMI was available at 5, 14 and 21 years of age. Catch-up growth was defined as increase of 0.67 Z-score in weight between measurements. The impact of catch-up growth on adult lung function and the relationship between childhood BMI trends and adult lung function was assessed using regression analyses. Results:Lung function was higher at 21 years in those demonstrating catch-up growth from birth to 5years;FVC [(males:5.33L v 5.54L), (females:3.78L v 4.03L)] and FEV1 [(males:4.52l/s v 4.64l/s), (females:3.31l/s v 3.45l/s)]. Subjects in the lowest quintile of birth [IUGR] also showed improved lung function if they had catch-up growth in the first five years of life.There was a positive correlation with increasing BMI and lung function at 5 years of age. However in the later measurements when BMI increases into the obese category a drop in lung function was observed. Conclusion:These data show evidence for a positive contribution of catch-up growth in early life to adult lung function. However, if weight gain or onset of obesity occurs after 5 years of age adverse impact on adult lung function is noted.
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A Rod-Packing Microporous Hydrogen-Bonded Organic Framework for Highly Selective Separation of C2 H2 /CO2 at Room Temperature.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 10-14-2014
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Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2 H2 /CO2 at ambient temperature and pressure.
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Melanoma Cells Break Down LPA to Establish Local Gradients That Drive Chemotactic Dispersal.
PLoS Biol.
PUBLISHED: 10-01-2014
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The high mortality of melanoma is caused by rapid spread of cancer cells, which occurs unusually early in tumour evolution. Unlike most solid tumours, thickness rather than cytological markers or differentiation is the best guide to metastatic potential. Multiple stimuli that drive melanoma cell migration have been described, but it is not clear which are responsible for invasion, nor if chemotactic gradients exist in real tumours. In a chamber-based assay for melanoma dispersal, we find that cells migrate efficiently away from one another, even in initially homogeneous medium. This dispersal is driven by positive chemotaxis rather than chemorepulsion or contact inhibition. The principal chemoattractant, unexpectedly active across all tumour stages, is the lipid agonist lysophosphatidic acid (LPA) acting through the LPA receptor LPAR1. LPA induces chemotaxis of remarkable accuracy, and is both necessary and sufficient for chemotaxis and invasion in 2-D and 3-D assays. Growth factors, often described as tumour attractants, cause negligible chemotaxis themselves, but potentiate chemotaxis to LPA. Cells rapidly break down LPA present at substantial levels in culture medium and normal skin to generate outward-facing gradients. We measure LPA gradients across the margins of melanomas in vivo, confirming the physiological importance of our results. We conclude that LPA chemotaxis provides a strong drive for melanoma cells to invade outwards. Cells create their own gradients by acting as a sink, breaking down locally present LPA, and thus forming a gradient that is low in the tumour and high in the surrounding areas. The key step is not acquisition of sensitivity to the chemoattractant, but rather the tumour growing to break down enough LPA to form a gradient. Thus the stimulus that drives cell dispersal is not the presence of LPA itself, but the self-generated, outward-directed gradient.
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Intermetallic Crystal Structures as Foams. Beyond Frank-Kasper.
Inorg Chem
PUBLISHED: 09-24-2014
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In many intermetallic structures, the atoms and bonds divide space into tilings by tetrahedra. The well-known Frank-Kasper phases are examples. The dual tilings divide space into a tiling by polyhedra that is topologically a foam. The number of faces of the dual polyhedron corresponds to the atom coordination number in the direct structure, and face sharing by adjacent polyhedra corresponds to bonds in the direct structure. A number of commonly occurring intermetallic crystal structures are shown as their duals. A major advantage of this alternative mode of depiction is that coordination of all of the atoms can be seen simultaneously.
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Astrocytes and neuroinflammation in Alzheimer's disease.
Biochem. Soc. Trans.
PUBLISHED: 09-19-2014
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Increased production of amyloid ?-peptide (A?) and altered processing of tau in Alzheimer's disease (AD) are associated with synaptic dysfunction, neuronal death and cognitive and behavioural deficits. Neuroinflammation is also a prominent feature of AD brain and considerable evidence indicates that inflammatory events play a significant role in modulating the progression of AD. The role of microglia in AD inflammation has long been acknowledged. Substantial evidence now demonstrates that astrocyte-mediated inflammatory responses also influence pathology development, synapse health and neurodegeneration in AD. Several anti-inflammatory therapies targeting astrocytes show significant benefit in models of disease, particularly with respect to tau-associated neurodegeneration. However, the effectiveness of these approaches is complex, since modulating inflammatory pathways often has opposing effects on the development of tau and amyloid pathology, and is dependent on the precise phenotype and activities of astrocytes in different cellular environments. An increased understanding of interactions between astrocytes and neurons under different conditions is required for the development of safe and effective astrocyte-based therapies for AD and related neurodegenerative diseases.
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Home, please: A conjoint analysis of patient preferences after a bad hip fracture.
Geriatr Gerontol Int
PUBLISHED: 09-09-2014
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An Australian study of older, community-dwelling women found that 80% would rather be dead than experience loss of independence and nursing home admission after a bad hip fracture. We re-examined this issue using a conjoint analysis approach.
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The proto-oncogene PBF binds p53 and is associated with prognostic features in colorectal cancer.
Mol. Carcinog.
PUBLISHED: 09-08-2014
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The PTTG1-binding factor (PBF) is a transforming gene capable of eliciting tumor formation in xenograft models. However, the precise role of PBF in tumorigenesis and its prognostic value as a cancer biomarker remain largely uncharacterised, particularly in malignancies outside the thyroid. Here, we provide the first evidence that PBF represents a promising prognostic marker in colorectal cancer. Examination of a total of 39 patients demonstrated higher PBF expression at both the mRNA (P?=?0.009) and protein (P??90%; P?
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Relationships between neonatal weight, limb lengths, skinfold thicknesses, body breadths and circumferences in an Australian cohort.
PLoS ONE
PUBLISHED: 08-27-2014
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Low birth weight has been consistently associated with adult chronic disease risk. The thrifty phenotype hypothesis assumes that reduced fetal growth impacts some organs more than others. However, it remains unclear how birth weight relates to different body components, such as circumferences, adiposity, body segment lengths and limb proportions. We hypothesized that these components vary in their relationship to birth weight.
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Positionable vertical microfluidic cell based on electromigration in a theta pipet.
Langmuir
PUBLISHED: 08-15-2014
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A microscale vertical fluidic cell system has been implemented, based on a simple theta pipet pulled to a sharp point (ca. 10-20 ?m diameter for the studies herein) and positioned with a high degree of control on a surface. The dual channel arrangement allows an electric field to be generated between an electrode in each compartment of the pipet that can be used to control the electromigration of charged species between the two compartments, across a thin liquid meniscus in contact with the substrate of interest. By visualizing the interfacial region using laser scanning confocal microscopy, the adsorption of fluorescently-labeled materials on surfaces is monitored quantitatively in real time, exemplified through studies of the adsorption of anionic microparticles (1.1 ?m diameter) on positively and negatively charged substrate surfaces of poly-L-lysine (PLL) and poly-L-glutamic acid (PGA), respectively, on glass. These studies highlight significant electrostatic effects on adsorption rates and also that the adsorption of these particles is dominated by the three phase meniscus/solid/air boundary. The technique is easily modified to the case of a submerged substrate, resulting in a much larger deposition area. Finite element method modeling is used to calculate local electric field strengths that are used to understand surface deposition patterns. To demonstrate the applicability of the technique to live biological substrates, the delivery of fluorescent particles directly to the surface of a single root hair cell of Zea mays is demonstrated. The mobile pipet allows deposition to be directed to specific regions of the cell, allowing discrete sites to be labeled with particles. Finally, the technique is used to study the uptake of fluorescent polymer molecules to single root hair cells, with quantitative analysis of the adsorption rates of vinyl-sulfonic acid copolymers, with varying rhodamine B content.
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Wnt5A promotes an adaptive, senescent-like stress response, while continuing to drive invasion in melanoma cells.
Pigment Cell Melanoma Res
PUBLISHED: 08-06-2014
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We have previously shown that Wnt5A drives invasion in melanoma. We have also shown that Wnt5A promotes resistance to therapy designed to target the BRAF(V600E) mutation in melanoma. Here, we show that melanomas characterized by high levels of Wnt5A respond to therapeutic stress by increasing p21 and expressing classical markers of senescence, including positivity for senescence-associated ?-galactosidase (SA-?-gal), senescence associated heterochromatic foci (SAHF), H3K9Me chromatin marks, and PML bodies. We find that despite this, these cells retain their ability to migrate and invade. Further, despite the expression of classic markers of senescence like SA-?-gal and SAHF, these Wnt5A-high cells are able to colonize the lungs in in vivo tail-vein colony forming assays. This clearly underscores the fact that these markers do not indicate true senescence in these cells, but instead an adaptive stress response that allows the cells to evade therapy and invade. Notably, silencing Wnt5A reduces expression of these markers and decreases invasiveness. The combined data point to Wnt5A as a master regulator of an adaptive stress response in melanoma, which may contribute to therapy resistance. This article is protected by copyright. All rights reserved.
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Conditional deletion of cardiomyocyte peroxisome proliferator-activated receptor ? enhances myocardial ischemia-reperfusion injury in mice.
Shock
PUBLISHED: 07-31-2014
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The nuclear transcription factor peroxisome proliferator-activated receptor ? (PPAR?) is a key regulator of the inflammatory response to an array of biologic insults. We have previously demonstrated that PPAR? ligands reduce myocardial ischemia-reperfusion injury in rodents. In the current study, we directly determined the role of cardiomyocyte PPAR? in ischemia-reperfusion injury, using a model of conditional cardiomyocyte-specific deletion of PPAR? in vivo. In mice, ?-myosin heavy chain-restricted Cre-mediated PPAR? deficiency was induced by tamoxifen treatment (30 mg/kg intraperitoneally) for 4 days (PPAR? mice), whereas controls included mice treated with the oil diluent vehicle (PPAR? mice). Western blot and histochemical analyses confirmed that expression of PPAR? protein was abolished in cardiomyocytes of mice treated with tamoxifen, but not with vehicle. After tamoxifen or vehicle treatment, animals were subjected to 30-min ligation of the left anterior descending coronary artery followed by 2-h reperfusion. In PPAR? mice, myocardial ischemia and reperfusion induced extensive myocardial damage, which was associated with elevated tissue activity of myeloperoxidase, indicating infiltration of neutrophils, and elevated plasma levels of troponin I when compared with PPAR? mice. Upon echocardiographic analysis, PPAR? mice also demonstrated ventricular dilatation and systolic dysfunction. Plasma levels of the proinflammatory cytokines interleukin 1? and interleukin 6 were higher in PPAR? mice when compared with PPAR? mice. These pathological events in PPAR? mice were associated with enhanced nuclear factor ?B DNA binding in the infarcted hearts. Thus, our data suggest that cardiomyocyte PPAR? is a crucial protective receptor and may prevent reperfusion injury by modulating mechanisms of inflammation.
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Long term follow up of high risk children: who, why and how?
BMC Pediatr
PUBLISHED: 07-23-2014
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Most babies are born healthy and grow and develop normally through childhood. There are, however, clearly identifiable high-risk groups of survivors, such as those born preterm or with ill-health, who are destined to have higher than expected rates of health or developmental problems, and for whom more structured and specialised follow-up programs are warranted.
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Is there a Role for Human Pluripotent Stem Cells in Modelling Interstitial Cells of Cajal and Gut Motility Disorders?
Curr Stem Cell Res Ther
PUBLISHED: 07-21-2014
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Gastrointestinal motility disorders affect millions of people worldwide, resulting in significant morbidity and mortality. Current treatments for these disorders are inadequate and often provide little to no relief for patients. As a result, gastrointestinal motility disorders produce substantial long-term social and economic burdens in both developed and developing countries. These limited treatment options arise largely from our relatively poor understanding of the molecular etiology for the majority of gastrointestinal motility disorders. In turn, this is due to our limited access to normal or diseased human gut tissue for use in research. In particular while the interstitial cells of Cajal are known to be important for gastrointestinal motility, little is known of how these cells function or how they are involved in disease initiation and progression. The advent of human pluripotent stem cell technology offers an opportunity to generate large amounts of human tissue for both research and clinical applications. The application of this technology to gastrointestinal motility disorders is currently only in its infancy and as yet no studies have described ICC production from human pluripotent cells. By considering the present understanding of the anatomical, cellular and molecular basis of gut motility with particular emphasis on the interstitial cells of Cajal, this review provides a clear framework for the application of human pluripotent stem cell technology to answer fundamental questions of ICC involvement in gut motility.
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Fatty Acid Uptake and Lipid Storage Induced by HIF-1? Contribute to Cell Growth and Survival after Hypoxia-Reoxygenation.
Cell Rep
PUBLISHED: 07-16-2014
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An in vivo model of antiangiogenic therapy allowed us to identify genes upregulated by bevacizumab treatment, including Fatty Acid Binding Protein 3 (FABP3) and FABP7, both of which are involved in fatty acid uptake. In vitro, both were induced by hypoxia in a hypoxia-inducible factor-1? (HIF-1?)-dependent manner. There was a significant lipid droplet (LD) accumulation in hypoxia that was time and O2 concentration dependent. Knockdown of endogenous expression of FABP3, FABP7, or Adipophilin (an essential LD structural component) significantly impaired LD formation under hypoxia. We showed that LD accumulation is due to FABP3/7-dependent fatty acid uptake while de novo fatty acid synthesis is repressed in hypoxia. We also showed that ATP production occurs via ?-oxidation or glycogen degradation in a cell-type-dependent manner in hypoxia-reoxygenation. Finally, inhibition of lipid storage reduced protection against reactive oxygen species toxicity, decreased the survival of cells subjected to hypoxia-reoxygenation in vitro, and strongly impaired tumorigenesis in vivo.
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Modulation of triglyceride and cholesterol ester synthesis impairs assembly of infectious hepatitis C virus.
J. Biol. Chem.
PUBLISHED: 06-10-2014
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In hepatitis C virus infection, replication of the viral genome and virion assembly are linked to cellular metabolic processes. In particular, lipid droplets, which store principally triacylglycerides (TAGs) and cholesterol esters (CEs), have been implicated in production of infectious virus. Here, we examine the effect on productive infection of triacsin C and YIC-C8-434, which inhibit synthesis of TAGs and CEs by targeting long-chain acyl-CoA synthetase and acyl-CoA:cholesterol acyltransferase, respectively. Our results present high resolution data on the acylglycerol and cholesterol ester species that were affected by the compounds. Moreover, triacsin C, which blocks both triglyceride and cholesterol ester synthesis, cleared most of the lipid droplets in cells. By contrast, YIC-C8-434, which only abrogates production of cholesterol esters, induced an increase in size of droplets. Although both compounds slightly reduced viral RNA synthesis, they significantly impaired assembly of infectious virions in infected cells. In the case of triacsin C, reduced stability of the viral core protein, which forms the virion nucleocapsid and is targeted to the surface of lipid droplets, correlated with lower virion assembly. In addition, the virus particles that were released from cells had reduced specific infectivity. YIC-C8-434 did not alter the association of core with lipid droplets but appeared to decrease production of infectious virus particles, suggesting a block in virion assembly. Thus, the compounds have antiviral properties, indicating that targeting synthesis of lipids stored in lipid droplets might be an option for therapeutic intervention in treating chronic hepatitis C virus infection.
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A GPU-accelerated immersive audio-visual framework for interaction with molecular dynamics using consumer depth sensors.
Faraday Discuss.
PUBLISHED: 06-06-2014
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With advances in computational power, the rapidly growing role of computational/simulation methodologies in the physical sciences, and the development of new human-computer interaction technologies, the field of interactive molecular dynamics seems destined to expand. In this paper, we describe and benchmark the software algorithms and hardware setup for carrying out interactive molecular dynamics utilizing an array of consumer depth sensors. The system works by interpreting the human form as an energy landscape, and superimposing this landscape on a molecular dynamics simulation to chaperone the motion of the simulated atoms, affecting both graphics and sonified simulation data. GPU acceleration has been key to achieving our target of 60 frames per second (FPS), giving an extremely fluid interactive experience. GPU acceleration has also allowed us to scale the system for use in immersive 360° spaces with an array of up to ten depth sensors, allowing several users to simultaneously chaperone the dynamics. The flexibility of our platform for carrying out molecular dynamics simulations has been considerably enhanced by wrappers that facilitate fast communication with a portable selection of GPU-accelerated molecular force evaluation routines. In this paper, we describe a 360° atmospheric molecular dynamics simulation we have run in a chemistry/physics education context. We also describe initial tests in which users have been able to chaperone the dynamics of 10-alanine peptide embedded in an explicit water solvent. Using this system, both expert and novice users have been able to accelerate peptide rare event dynamics by 3-4 orders of magnitude.
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Methylated glycans as conserved targets of animal and fungal innate defense.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-30-2014
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Effector proteins of innate immune systems recognize specific non-self epitopes. Tectonins are a family of ?-propeller lectins conserved from bacteria to mammals that have been shown to bind bacterial lipopolysaccharide (LPS). We present experimental evidence that two Tectonins of fungal and animal origin have a specificity for O-methylated glycans. We show that Tectonin 2 of the mushroom Laccaria bicolor (Lb-Tec2) agglutinates Gram-negative bacteria and exerts toxicity toward the model nematode Caenorhabditis elegans, suggesting a role in fungal defense against bacteria and nematodes. Biochemical and genetic analysis of these interactions revealed that both bacterial agglutination and nematotoxicity of Lb-Tec2 depend on the recognition of methylated glycans, namely O-methylated mannose and fucose residues, as part of bacterial LPS and nematode cell-surface glycans. In addition, a C. elegans gene, termed samt-1, coding for a candidate membrane transport protein for the presumptive donor substrate of glycan methylation, S-adenosyl-methionine, from the cytoplasm to the Golgi was identified. Intriguingly, limulus lectin L6, a structurally related antibacterial protein of the Japanese horseshoe crab Tachypleus tridentatus, showed properties identical to the mushroom lectin. These results suggest that O-methylated glycans constitute a conserved target of the fungal and animal innate immune system. The broad phylogenetic distribution of O-methylated glycans increases the spectrum of potential antagonists recognized by Tectonins, rendering this conserved protein family a universal defense armor.
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Lipid droplet formation in response to oleic acid in Huh-7 cells is mediated by the fatty acid receptor FFAR4.
J. Cell. Sci.
PUBLISHED: 05-29-2014
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It is unclear how changes in lipid droplet size and number are regulated - for example, it is not known whether this involves a signalling pathway or is directed by cellular lipid uptake. Here, we show that oleic acid stimulates lipid droplet formation by activating the long-chain fatty acid receptor FFAR4, which signals through a pertussis-toxin-sensitive G-protein signalling pathway involving phosphoinositide 3-kinase (PI3-kinase), AKT (also known as protein kinase B) and phospholipase D (PLD) activities. This initial lipid droplet formation is not dependent upon exogenous lipid, whereas the subsequent more sustained increase in the number of lipid droplets is dependent upon lipid uptake. These two mechanisms of lipid droplet formation point to distinct potential intervention points.
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A novel mouse model for inhibition of DOHH-mediated hypusine modification reveals a crucial function in embryonic development, proliferation and oncogenic transformation.
Dis Model Mech
PUBLISHED: 05-15-2014
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The central importance of translational control by post-translational modification has spurred major interest in regulatory pathways that control translation. One such pathway uniquely adds hypusine to eukaryotic initiation factor 5A (eIF5A), and thereby affects protein synthesis and, subsequently, cellular proliferation through an unknown mechanism. Using a novel conditional knockout mouse model and a Caenorhabditis elegans knockout model, we found an evolutionarily conserved role for the DOHH-mediated second step of hypusine synthesis in early embryonic development. At the cellular level, we observed reduced proliferation and induction of senescence in 3T3 Dohh-/- cells as well as reduced capability for malignant transformation. Furthermore, mass spectrometry showed that deletion of DOHH results in an unexpected complete loss of hypusine modification. Our results provide new biological insight into the physiological roles of the second step of the hypusination of eIF5A. Moreover, the conditional mouse model presented here provides a powerful tool for manipulating hypusine modification in a temporal and spatial manner, to analyse both how this unique modification normally functions in vivo as well as how it contributes to different pathological conditions.
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Apoptotic cell death under hypoxia.
Physiology (Bethesda)
PUBLISHED: 05-03-2014
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Eukaryotic life depends largely on molecular oxygen. During evolution, ingenious mechanisms have evolved that allow organisms to adapt when oxygen levels decrease. Many of these adaptional responses to low oxygen are orchestrated by the heterodimeric transcription factor hypoxia-inducible factor (HIF). Here, we review the link between HIF and apoptosis.
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DEPDC1/LET-99 participates in an evolutionarily conserved pathway for anti-tubulin drug-induced apoptosis.
Nat. Cell Biol.
PUBLISHED: 03-03-2014
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Microtubule-targeting chemotherapeutics induce apoptosis in cancer cells by promoting the phosphorylation and degradation of the anti-apoptotic BCL-2 family member MCL1. The signalling cascade linking microtubule disruption to MCL1 degradation remains however to be defined. Here, we establish an in vivo screening strategy in Caenorhabditis elegans to uncover genes involved in chemotherapy-induced apoptosis. Using an RNAi-based screen, we identify three genes required for vincristine-induced apoptosis. We show that the DEP domain protein LET-99 acts upstream of the heterotrimeric G protein alpha subunit GPA-11 to control activation of the stress kinase JNK-1. The human homologue of LET-99, DEPDC1, similarly regulates vincristine-induced cell death by promoting JNK-dependent degradation of the BCL-2 family protein MCL1. Collectively, these data uncover an evolutionarily conserved mediator of anti-tubulin drug-induced apoptosis and suggest that DEPDC1 levels could be an additional determinant for therapy response upstream of MCL1.
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The uses and limitations of the analysis of cellular phosphoinositides by lipidomic and imaging methodologies.
Biochim. Biophys. Acta
PUBLISHED: 01-30-2014
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The advent of mass spectrometric methods has facilitated the determination of multiple molecular species of cellular lipid classes including the polyphosphoinositides, though to date methods to analyse and quantify each of the individual three PtdInsP and three PtdInsP2 species are lacking. The use of imaging methods has allowed intracellular localization of the phosphoinositide classes but this methodology does not determine the acyl structures. The range of molecular species suggests a greater complexity in polyphosphoinositide signaling than yet defined but elucidating this will require further method development to be achieved. This article is part of a Special Issue entitled Tools to study lipid functions.
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A novel in vivo model of tau propagation with rapid and progressive neurofibrillary tangle pathology: the pattern of spread is determined by connectivity, not proximity.
Acta Neuropathol.
PUBLISHED: 01-30-2014
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Intracellular inclusions composed of hyperphosphorylated filamentous tau are a hallmark of Alzheimer's disease, progressive supranuclear palsy, Pick's disease and other sporadic neurodegenerative tauopathies. Recent in vitro and in vivo studies have shown that tau aggregates do not only seed further tau aggregation within neurons, but can also spread to neighbouring cells and functionally connected brain regions. This process is referred to as 'tau propagation' and may explain the stereotypic progression of tau pathology in the brains of Alzheimer's disease patients. Here, we describe a novel in vivo model of tau propagation using human P301S tau transgenic mice infused unilaterally with brain extract containing tau aggregates. Infusion-related neurofibrillary tangle pathology was first observed 2 weeks post-infusion and increased in a stereotypic, time-dependent manner. Contralateral and anterior/posterior spread of tau pathology was also evident in nuclei with strong synaptic connections (efferent and afferent) to the site of infusion, indicating that spread was dependent on synaptic connectivity rather than spatial proximity. This notion was further supported by infusion-related tau pathology in white matter tracts that interconnect these regions. The rapid and robust propagation of tau pathology in this model will be valuable for both basic research and the drug discovery process.
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Diverse effects of residues 74-78 in ribosomal protein S12 on decoding and antibiotic sensitivity.
Biochem. Biophys. Res. Commun.
PUBLISHED: 01-28-2014
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Ribosomal protein S12 plays key roles in the ribosome's response to the error-promoting antibiotic streptomycin and in modulating the accuracy of translation. The discovery that substitutions at His76 in S12, distant from the streptomycin binding site, conferred streptomycin resistance in the thermophilic bacterium Thermus thermophilus prompted us to make similar alterations in the S12 protein of Escherichia coli. While, none of the E. coli S12 mutations confers streptomycin resistance, they all have distinct effects on the accuracy of translation. In addition, a subset of the S12 alterations renders the cells hypersensitive to fusidic acid, an inhibitor of the translocation step of translation. These results indicate that the His 76 region of ribosomal protein S12 plays key roles in tRNA selection and translocation steps of protein synthesis, consistent with its interaction with elongation factors EF-Tu and EF-G, as deduced from structural studies of ribosomal complexes.
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Combined zinc supplementation with proinsulin C-peptide treatment decreases the inflammatory response and mortality in murine polymicrobial sepsis.
Shock
PUBLISHED: 01-17-2014
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Zinc is a trace element vital for immune function during host response to infection. The proinsulin C-peptide has been shown to exert beneficial effects through activation of the anti-inflammatory peroxisome proliferator-activated receptor ? (PPAR?) in experimental endotoxemia. Some in vitro activities of C-peptide appear dependent on the presence of zinc. We investigated the effect of zinc supplementation before onset of sepsis on the anti-inflammatory properties of C-peptide. Male C57BL/6 mice were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). Mice received zinc gluconate (1.3 mg/kg) intraperitoneally (i.p.) for 3 days before CLP. One hour after CLP, animals received C-peptide (280 nmol/kg i.p.) or the antimicrobial agent imipenem (25 mg/kg i.p.). Cecal ligation and puncture was associated with an 11% survival rate, pulmonary leukosequestration, and liver injury. Molecular analysis in lungs of septic mice showed increased nuclear activation of the proinflammatory extracellular signal-regulated kinases 1 and 2 and nuclear factor ?B, but decreased PPAR? expression, when compared with sham animals. Combination of zinc supplementation with C-peptide posttreatment significantly improved survival rate (61%) similarly to antibiotic treatment (60%), ameliorated lung architecture and liver function, reduced tissue neutrophil infiltration, and increased bacterial clearance when compared with vehicle, C-peptide, or zinc treatment alone. These beneficial effects were associated with restored lung nuclear expression of PPAR? and reduction of phosphorylated extracellular signal-regulated kinases 1 and 2 and nuclear factor ?B activities in comparison to vehicle or single treatment protocols. Our data demonstrate that short-term zinc prophylaxis before the infectious insult is a requisite for the anti-inflammatory properties of C-peptide by facilitating modulation of inflammatory pathways.
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The antibiotics dityromycin and GE82832 bind protein S12 and block EF-G-catalyzed translocation.
Cell Rep
PUBLISHED: 01-09-2014
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The translocation of mRNA and tRNA through the ribosome is catalyzed by elongation factor G (EF-G), a universally conserved guanosine triphosphate hydrolase (GTPase). The mechanism by which the closely related decapeptide antibiotics dityromycin and GE82832 inhibit EF-G-catalyzed translocation is elucidated in this study. Using crystallographic and biochemical experiments, we demonstrate that these antibiotics bind to ribosomal protein S12 in solution alone as well as within the small ribosomal subunit, inducing long-range effects on the ribosomal head. The crystal structure of the antibiotic in complex with the 70S ribosome reveals that the binding involves conserved amino acid residues of S12 whose mutations result in in vitro and in vivo antibiotic resistance and loss of antibiotic binding. The data also suggest that GE82832/dityromycin inhibits EF-G-catalyzed translocation by disrupting a critical contact between EF-G and S12 that is required to stabilize the posttranslocational conformation of EF-G, thereby preventing the ribosome-EF-G complex from entering a conformation productive for translocation.
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Efficacy and tolerability of celecoxib and naproxen versus placebo in Hispanic patients with knee osteoarthritis.
Int J Gen Med
PUBLISHED: 01-01-2014
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Celecoxib is an effective treatment for osteoarthritis (OA). However, information on its efficacy and safety profile in different racial/ethnic groups is limited. Noticeable differences among racial groups are found in other disease states, but a thorough investigation of OA is lacking. The objective of this study was to determine if celecoxib 200 mg once daily is as effective as naproxen 500 mg twice daily in the treatment of OA of the knee in Hispanic patients.
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Rigid, flexible and impossible zeolite and related structures.
Philos Trans A Math Phys Eng Sci
PUBLISHED: 12-30-2013
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The flexibility or otherwise of periodic tetrahedral TX2 frameworks formed by corner-sharing regular TX4 tetrahedra is discussed. In particular, when T-X-T angle constraints are included, a suitable embedding can often only be found, if at all, in an symmetry less than the maximum possible for that topology. Examples illustrating this are adduced.
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Bone Morphogenetic Proteins Signal Via SMAD and Mitogen-activated Protein (MAP) Kinase Pathways at Distinct Times during Osteoclastogenesis.
J. Biol. Chem.
PUBLISHED: 11-14-2013
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To investigate the role of bone morphogenetic protein (BMP) signaling in osteoclastogenesis in vivo, we eliminated BMPRII in osteoclasts by creating a BMPRII(fl/fl);lysM-Cre mouse strain. Conditional knock-out (cKO) mice are osteopetrotic when compared with WT controls due to a decrease in osteoclast activity. Bone marrow macrophages (BMMs) isolated from cKO mice are severely inhibited in their capacity to differentiate into mature osteoclasts in the presence of M-CSF and receptor activator of NF-?B (RANK) ligand. We also show that BMP noncanonical (MAPK) and canonical (SMAD) pathways are utilized at different stages of osteoclast differentiation. BMP2 induces p38 phosphorylation in pre-fusion osteoclasts and increases SMAD phosphorylation around osteoclast precursor fusion. Phosphorylation of MAPKs was decreased in differentiated BMMs from cKO animals. Treating BMMs with the SMAD inhibitor dorsomorphin confirms the requirement for the canonical pathway around the time of fusion. These results demonstrate the requirement for BMP signaling in osteoclasts for proper bone homeostasis and also explore the complex signaling mechanisms employed by BMP signaling during osteoclast differentiation.
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Cesarean Delivery and Cerebral Palsy: A Systematic Review and Meta-analysis.
Obstet Gynecol
PUBLISHED: 11-09-2013
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To examine the association of cesarean delivery and cerebral palsy using a systematic literature review and meta-analysis.
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Cesarean delivery and the long-term risk of offspring obesity.
Obstet Gynecol
PUBLISHED: 11-09-2013
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To examine the association between the mode of delivery and the risk of offspring obesity by age 21 years using a large community-based birth cohort study in Australia.
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Lipidomics in the analysis of malignancy.
Adv Biol Regul
PUBLISHED: 11-01-2013
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Lipidomic methodologies have developed such that determination in lipid species content of cells and tissues is increasingly achievable. Adoption of these methods is highlighting the physiological importance of individual lipid molecular species rather than changes in an overall lipid class. In this article the use of such methodologies is considered and the potential for understanding the importance of lipid changes in malignancy assessed.
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Ribosome Synthesis and MAPK Activity Modulate Ionizing Radiation-Induced Germ Cell Apoptosis in Caenorhabditis elegans.
PLoS Genet.
PUBLISHED: 11-01-2013
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Synthesis of ribosomal RNA by RNA polymerase I (RNA pol I) is an elemental biological process and is key for cellular homeostasis. In a forward genetic screen in C. elegans designed to identify DNA damage-response factors, we isolated a point mutation of RNA pol I, rpoa-2(op259), that leads to altered rRNA synthesis and a concomitant resistance to ionizing radiation (IR)-induced germ cell apoptosis. This weak apoptotic IR response could be phenocopied when interfering with other factors of ribosome synthesis. Surprisingly, despite their resistance to DNA damage, rpoa-2(op259) mutants present a normal CEP-1/p53 response to IR and increased basal CEP-1 activity under normal growth conditions. In parallel, rpoa-2(op259) leads to reduced Ras/MAPK pathway activity, which is required for germ cell progression and physiological germ cell death. Ras/MAPK gain-of-function conditions could rescue the IR response defect in rpoa-2(op259), pointing to a function for Ras/MAPK in modulating DNA damage-induced apoptosis downstream of CEP-1. Our data demonstrate that a single point mutation in an RNA pol I subunit can interfere with multiple key signalling pathways. Ribosome synthesis and growth-factor signalling are perturbed in many cancer cells; such an interplay between basic cellular processes and signalling might be critical for how tumours evolve or respond to treatment.
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Long-term restorative effects of bromocriptine on operant responding in the 6-hydroxydopamine-lesioned rat.
Neuroreport
PUBLISHED: 10-23-2013
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Despite recent recognition of the complexity of the motor and nonmotor dysfunctions that manifest in Parkinsons disease, the propensity of drugs to alleviate the dopamine-dependent symptoms in the 6-hydroxydopamine rat model is still typically being assessed using relatively simple measures of motor function. We investigated the ability of the D2 agonist, bromocriptine, to ameliorate impairments in a more complex operant task, which simultaneously assessed both motor and nonmotor deficits. Rats were trained on a lateralized choice reaction time task that has previously been found to be sensitive to dopamine depletion. One subgroup of rats was then given unilateral 6-hydroxydopamine lesions of the medial forebrain bundle. Once they exhibited stable postlesion deficits, the rats in the lesion group were administered bromocriptine (1.25 mg/kg) 120 min before testing. Bromocriptine induced a transient improvement in motor function but most notably produced a persistent improvement in the accuracy of performance in the task. The improvement in response initiation and selection persisted on testing in the absence of bromocriptine and was not reversed by the D2 antagonist, raclopride (0.2 mg/kg). These results may reflect a conditioning effect of bromocriptine on operant behaviour.
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Hypoxia Induces Phenotypic Plasticity and Therapy Resistance in Melanoma via the Tyrosine Kinase Receptors ROR1 and ROR2.
Cancer Discov
PUBLISHED: 10-08-2013
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An emerging concept in melanoma biology is that of dynamic, adaptive phenotype switching, where cells switch from a highly proliferative, poorly invasive phenotype to a highly invasive, less proliferative one. This switch may hold significant implications not just for metastasis, but also for therapy resistance. We demonstrate that phenotype switching and subsequent resistance can be guided by changes in expression of receptors involved in the noncanonical Wnt5A signaling pathway, ROR1 and ROR2. ROR1 and ROR2 are inversely expressed in melanomas and negatively regulate each other. Furthermore, hypoxia initiates a shift of ROR1-positive melanomas to a more invasive, ROR2-positive phenotype. Notably, this receptor switch induces a 10-fold decrease in sensitivity to BRAF inhibitors. In patients with melanoma treated with the BRAF inhibitor vemurafenib, Wnt5A expression correlates with clinical response and therapy resistance. These data highlight the fact that mechanisms that guide metastatic progression may be linked to those that mediate therapy resistance.
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Model organisms proteomics--from holobionts to human nutrition.
Proteomics
PUBLISHED: 09-17-2013
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Model organisms are an important tool for the development and validation of analytical approaches for proteomics and for the study of basic mechanisms of biological processes. The Initiative on Model Organism Proteomics (iMOP) organized a session during the 11th HUPO World Congress in Boston in 2012, highlighting the potential of proteomics studies in model organism for the elucidation of important mechanisms regulating the interaction of humans with its environment. Major subjects were the use of model organisms for the study of molecular events triggering the interaction of host organisms with the surrounding microbiota and the elucidation of the complex influence of nutrition on the health of human beings.
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Change is in the air: the hypoxic induction of phenotype switching in melanoma.
J. Invest. Dermatol.
PUBLISHED: 09-14-2013
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Melanoma cells can switch from a highly proliferative, less invasive state to a highly invasive, less proliferative state, a phenomenon termed phenotype switching. This results in a highly heterogenous tumor, where a slow-growing, aggressive population of cells may resist tumor therapy, and it predicts tumor recurrence. Here we discuss the observation made by Widmer et al. that hypoxia may drive phenotype switching.
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Creating a gold medal Olympic and Paralympics health care team: a satisfaction survey of the mobile medical unit/polyclinic team training for the Vancouver 2010 winter games.
BMC Res Notes
PUBLISHED: 09-03-2013
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The mobile medical unit/polyclinic (MMU/PC) was an essential part of the medical services to support ill or injured Olympic or Paralympics family during the 2010 Olympic and Paralympics winter games. The objective of this study was to survey the satisfaction of the clinical staff that completed the training programs prior to deployment to the MMU.
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Aptamers as theranostic agents: modifications, serum stability and functionalisation.
Sensors (Basel)
PUBLISHED: 08-07-2013
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Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents.
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Inflammation and cancer stem cells.
Cancer Lett.
PUBLISHED: 06-21-2013
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Cancer stem cells are becoming recognised as being responsible for metastasis and treatment resistance. The complex cellular and molecular network that regulates cancer stem cells and the role that inflammation plays in cancer progression are slowly being elucidated. Cytokines, secreted by tumour associated immune cells, activate the necessary pathways required by cancer stem cells to facilitate cancer stem cells progressing through the epithelial-mesenchymal transition and migrating to distant sites. Once in situ, these cancer stem cells can secrete their own attractants, thus providing an environment whereby these cells can continue to propagate the tumour in a secondary niche.
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Thermal effects of transcranial near-infrared laser irradiation on rabbit cortex.
Neurosci. Lett.
PUBLISHED: 06-10-2013
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Transcranial near-infrared laser therapy (TLT) improves stroke outcome in animal models. Adequate laser doses are necessary to exert therapeutic effects. However, applying higher laser energy may cause cortical tissue heating and exacerbate stroke injury. The objective of this study is to examine the thermal effect and safety of transcranial near-infrared laser therapy. Diode laser with a wavelength of 808 nm was used to deliver different power densities to the brain cortex of rabbits. Cortical temperature was monitored and measured using a thermal probe during the 2 min transcranial laser irradiation. Neuro-pathological changes were examined with histological staining 24 h after laser treatment. Transcranial laser irradiation for 2 min at cortical power densities of 22.2 and 55.6 mW/cm(2) with continuous wave (CW) did not increase cortical temperature in rabbits. With the same treatment regime, cortical power density at 111.1 mW/cm(2) increased brain temperature gradually by 0.5 °C over the 2 min exposure and returned to baseline values within 1-2 min post-irradiation. Separately, histological staining was evaluated after triple laser exposure of 22.2 mW/cm(2) CW and 111.1 mW/cm(2) pulse wave (PW) and showed normal neural cell morphology. The present study demonstrated that the TLT powers currently utilized in animal stroke studies do not cause cortical tissue heating and histopathological damage.
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Nets with collisions (unstable nets) and crystal chemistry.
Acta Crystallogr., A, Found. Crystallogr.
PUBLISHED: 06-05-2013
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Nets in which different vertices have identical barycentric coordinates (i.e. have collisions) are called unstable. Some such nets have automorphisms that do not correspond to crystallographic symmetries and are called non-crystallographic. Examples are given of nets taken from real crystal structures which have embeddings with crystallographic symmetry in which colliding nodes either are, or are not, topological neighbors (linked) and in which some links coincide. An example is also given of a crystallographic net of exceptional girth (16), which has collisions in barycentric coordinates but which also has embeddings without collisions with the same symmetry. In this last case the collisions are termed unforced.
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Knockdown of diacylglycerol kinase delta inhibits adipocyte differentiation and alters lipid synthesis.
Obesity (Silver Spring)
PUBLISHED: 05-23-2013
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Decreased expression of diacylglycerol kinase delta (DGK?) has been linked to insulin resistance in humans and mice and it is abundantly expressed in adipose tissue. Therefore, its role in adipogenesis was examined.
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Mitochondria as a target of environmental toxicants.
Toxicol. Sci.
PUBLISHED: 04-29-2013
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Enormous strides have recently been made in our understanding of the biology and pathobiology of mitochondria. Many diseases have been identified as caused by mitochondrial dysfunction, and many pharmaceuticals have been identified as previously unrecognized mitochondrial toxicants. A much smaller but growing literature indicates that mitochondria are also targeted by environmental pollutants. We briefly review the importance of mitochondrial function and maintenance for health based on the genetics of mitochondrial diseases and the toxicities resulting from pharmaceutical exposure. We then discuss how the principles of mitochondrial vulnerability illustrated by those fields might apply to environmental contaminants, with particular attention to factors that may modulate vulnerability including genetic differences, epigenetic interactions, tissue characteristics, and developmental stage. Finally, we review the literature related to environmental mitochondrial toxicants, with a particular focus on those toxicants that target mitochondrial DNA. We conclude that the fields of environmental toxicology and environmental health should focus more strongly on mitochondria.
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Application of receiver operating characteristic analysis to refine the prediction of potential digoxin drug interactions.
Drug Metab. Dispos.
PUBLISHED: 04-25-2013
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In the 2012 Food and Drug Administration (FDA) draft guidance on drug-drug interactions (DDIs), a new molecular entity that inhibits P-glycoprotein (P-gp) may need a clinical DDI study with a P-gp substrate such as digoxin when the maximum concentration of inhibitor at steady state divided by IC?? ([I?]/IC??) is ?0.1 or concentration of inhibitor based on highest approved dose dissolved in 250 ml divide by IC?? ([I?]/IC??) is ?10. In this article, refined criteria are presented, determined by receiver operating characteristic analysis, using IC?? values generated by 23 laboratories. P-gp probe substrates were digoxin for polarized cell-lines and N-methyl quinidine or vinblastine for P-gp overexpressed vesicles. Inhibition of probe substrate transport was evaluated using 15 known P-gp inhibitors. Importantly, the criteria derived in this article take into account variability in IC?? values. Moreover, they are statistically derived based on the highest degree of accuracy in predicting true positive and true negative digoxin DDI results. The refined criteria of [I?]/IC?? ? 0.03 and [I?]/IC?? ? 45 and FDA criteria were applied to a test set of 101 in vitro-in vivo digoxin DDI pairs collated from the literature. The number of false negatives (none predicted but DDI observed) were similar, 10 and 12%, whereas the number of false positives (DDI predicted but not observed) substantially decreased from 51 to 40%, relative to the FDA criteria. On the basis of estimated overall variability in IC?? values, a theoretical 95% confidence interval calculation was developed for single laboratory IC?? values, translating into a range of [I?]/IC?? and [I?]/IC?? values. The extent by which this range falls above the criteria is a measure of risk associated with the decision, attributable to variability in IC?? values.
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Shorthand notation for lipid structures derived from mass spectrometry.
J. Lipid Res.
PUBLISHED: 04-02-2013
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There is a need for a standardized, practical annotation for structures of lipid species derived from mass spectrometric approaches; i.e., for high-throughput data obtained from instruments operating in either high- or low-resolution modes. This proposal is based on common, officially accepted terms and builds upon the LIPID MAPS terminology. It aims to add defined levels of information below the LIPID MAPS nomenclature, as detailed chemical structures, including stereochemistry, are usually not automatically provided by mass spectrometric analysis. To this end, rules for lipid species annotation were developed that reflect the structural information derived from the analysis. For example, commonly used head group-specific analysis of glycerophospholipids (GP) by low-resolution instruments is neither capable of differentiating the fatty acids linked to the glycerol backbone nor able to define their bond type (ester, alkyl-, or alk-1-enyl-ether). This and other missing structural information is covered by the proposed shorthand notation presented here. Beyond GPs, we provide shorthand notation for fatty acids/acyls (FA), glycerolipids (GL), sphingolipids (SP), and sterols (ST). In summary, this defined shorthand nomenclature provides a standard methodology for reporting lipid species from mass spectrometric analysis and for constructing databases.
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Lipidome analysis of rotavirus-infected cells confirms the close interaction of lipid droplets with viroplasms.
J. Gen. Virol.
PUBLISHED: 03-20-2013
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Rotaviruses (RVs) cause acute gastroenteritis in infants and young children, and are globally distributed. Within the infected host cell, RVs establish replication complexes in viroplasms (viral factories) to which lipid droplet organelles are recruited. To further understand this recently discovered phenomenon, the lipidomes of RV-infected and uninfected MA104 cells were investigated. Cell lysates were subjected to equilibrium ultracentrifugation through iodixanol gradients. Fourteen different classes of lipids were differentiated by mass spectrometry. The concentrations of virtually all lipids were elevated in RV-infected cells. Fractions of low density (1.11-1.15 g ml?¹), in which peaks of the RV dsRNA genome and lipid droplet- and viroplasm-associated proteins were observed, contained increased amounts of lipids typically found concentrated in the cellular organelle lipid droplets, confirming the close interaction of lipid droplets with viroplasms. A decrease in the ratio of the amounts of surface to internal components of lipid droplets upon RV infection suggested that the lipid droplet-viroplasm complexes became enlarged.
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Does depression experienced by mothers leads to a decline in marital quality: a 21-year longitudinal study.
Soc Psychiatry Psychiatr Epidemiol
PUBLISHED: 03-19-2013
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Marital conflict and/or marital breakdown are known pathways to the onset of depression. Few studies however have examined the possibility that depression can lead to a decrease in marital quality and an increase in marital breakdown. Depression may be an important pathway to a decline in martial quality.
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Meniscus confined fabrication of multidimensional conducting polymer nanostructures with scanning electrochemical cell microscopy (SECCM).
Chem. Commun. (Camb.)
PUBLISHED: 03-06-2013
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Scanning electrochemical cell microscopy (SECCM) is demonstrated as a new approach for the construction of extended multi-dimensional conducting polymer (polyaniline) nanostructures, making use of a mobile dual-channel theta pipette cell to control and monitor the location, rate and extent of electropolymerisation.
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Determination of dosage compensation of the mammalian X chromosome by RNA-seq is dependent on analytical approach.
BMC Genomics
PUBLISHED: 02-23-2013
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An enduring question surrounding sex chromosome evolution is whether effective hemizygosity in the heterogametic sex leads inevitably to dosage compensation of sex-linked genes, and whether this compensation has been observed in a variety of organisms. Incongruence in the conclusions reached in some recent reports has been attributed to different high-throughput approaches to transcriptome analysis. However, recent reports each utilizing RNA-seq to gauge X-linked gene expression relative to autosomal gene expression also arrived at diametrically opposed conclusions regarding X chromosome dosage compensation in mammals.
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Methadone dosing and prescribed medication use in a prospective cohort of opioid-dependent pregnant women.
Addiction
PUBLISHED: 02-11-2013
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This study aimed to (i) describe methadone dosing before, during and after pregnancy, (ii) to compare the incidence of neonatal abstinence syndrome (NAS) between those with dose decreases and those with steady or increasing doses and (iii) to describe prescribed medication use among opioid-dependent pregnant women.
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Child maltreatment and adolescent mental health problems in a large birth cohort.
Child Abuse Negl
PUBLISHED: 02-04-2013
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To examine whether notified child maltreatment is associated with adverse psychological outcomes in adolescence, and whether differing patterns of psychological outcome are seen depending on the type of maltreatment.
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Hypermorphic expression of centromeric retroelement-encoded small RNAs impairs CENP-A loading.
Chromosome Res.
PUBLISHED: 01-22-2013
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The proper functioning of centromeres requires a complex cascade of epigenetic events involving chromatin and kinetochore assembly; however, the precise mechanism by which this cascade proceeds is unknown. The pivotal event during kinetochore formation is the "loading," or deposition, of CENP-A. This histone H3 variant is specific to centromeres and replaces conventional H3 in centromeric chromatin. Failure to load CENP-A into mammalian centromeres in late telophase/early G1 of the cell cycle leads to malsegregation and cell division defects in subsequent cell cycles. Mounting evidence supports the hypothesis that an RNA component is involved, although how RNAs participate in centromere formation in mammals has remained unknown. Using the marsupial model, the tammar wallaby, we show that centromeric retroelements produce small RNAs and that hypermorphic expression of these centromeric small RNAs results in disruption of CENP-A localization. We propose that tight regulation of the processing of this new class of small RNAs, crasiRNAs, is an integral component of the epigenetic framework necessary for centromere establishment.
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Enzyme replacement therapy rescues weakness and improves muscle pathology in mice with X-linked myotubular myopathy.
Hum. Mol. Genet.
PUBLISHED: 01-09-2013
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No effective treatment exists for patients with X-linked myotubular myopathy (XLMTM), a fatal congenital muscle disease caused by deficiency of the lipid phosphatase, myotubularin. The Mtm1?4 and Mtm1 p.R69C mice model severely and moderately symptomatic XLMTM, respectively, due to differences in the degree of myotubularin deficiency. Contractile function of intact extensor digitorum longus (EDL) and soleus muscles from Mtm1?4 mice, which produce no myotubularin, is markedly impaired. Contractile forces generated by chemically skinned single fiber preparations from Mtm1?4 muscle were largely preserved, indicating that weakness was largely due to impaired excitation contraction coupling. Mtm1 p.R69C mice, which produce small amounts of myotubularin, showed impaired contractile function only in EDL muscles. Short-term replacement of myotubularin with a prototypical targeted protein replacement agent (3E10Fv-MTM1) in Mtm1?4 mice improved contractile function and muscle pathology. These promising findings suggest that even low levels of myotubularin protein replacement can improve the muscle weakness and reverse the pathology that characterizes XLMTM.
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A network of HSPG core proteins and HS modifying enzymes regulates netrin-dependent guidance of D-type motor neurons in Caenorhabditis elegans.
PLoS ONE
PUBLISHED: 01-01-2013
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Heparan sulfate proteoglycans (HSPGs) are proteins with long covalently attached sugar side chains of the heparan sulfate (HS) type. Depending on the cellular context HS chains carry multiple structural modifications such as sulfate residues or epimerized sugars allowing them to bind to a wide range of molecules. HSPGs have been found to play extremely diverse roles in animal development and were shown to interact with certain axon guidance molecules. In this study we describe the role of the Caenorhabditis elegans HSPG core proteins Syndecan (SDN-1) and Glypican (LON-2) and the HS modifying enzymes in the dorsal guidance of D-type motor axons, a process controlled mainly by the conserved axon guidance molecule UNC-6/Netrin. Our genetic analysis established the specific HS code relevant for this axon guidance event. Using two sensitized genetic backgrounds, we isolated novel components influencing D-type motor axon guidance with a link to HSPGs, as well as new alleles of several previously characterized axon guidance genes. Interestingly, the dorsal axon guidance defects induced by mutations in zfp-1 or lin-35 depended on the transgene oxIs12 used to visualize the D-type motor neurons. oxIs12 is a large multi-copy transgene that enlarges the X chromosome by approximately 20%. In a search for genes with a comparable phenotype we found that a mutation in the known dosage compensation gene dpy-21 showed similar axon guidance defects as zfp-1 or lin-35 mutants. Thus, derepression of genes on X, where many genes relevant for HS dependent axon guidance are located, might also influence axon guidance of D-type motor neurons.
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LipidHome: a database of theoretical lipids optimized for high throughput mass spectrometry lipidomics.
PLoS ONE
PUBLISHED: 01-01-2013
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Protein sequence databases are the pillar upon which modern proteomics is supported, representing a stable reference space of predicted and validated proteins. One example of such resources is UniProt, enriched with both expertly curated and automatic annotations. Taken largely for granted, similar mature resources such as UniProt are not available yet in some other "omics" fields, lipidomics being one of them. While having a seasoned community of wet lab scientists, lipidomics lies significantly behind proteomics in the adoption of data standards and other core bioinformatics concepts. This work aims to reduce the gap by developing an equivalent resource to UniProt called LipidHome, providing theoretically generated lipid molecules and useful metadata. Using the FASTLipid Java library, a database was populated with theoretical lipids, generated from a set of community agreed upon chemical bounds. In parallel, a web application was developed to present the information and provide computational access via a web service. Designed specifically to accommodate high throughput mass spectrometry based approaches, lipids are organised into a hierarchy that reflects the variety in the structural resolution of lipid identifications. Additionally, cross-references to other lipid related resources and papers that cite specific lipids were used to annotate lipid records. The web application encompasses a browser for viewing lipid records and a tools section where an MS1 search engine is currently implemented. LipidHome can be accessed at http://www.ebi.ac.uk/apweiler-srv/lipidhome.
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Selective remediation of reversal learning deficits in the neurodevelopmental MAM model of schizophrenia by a novel mGlu5 positive allosteric modulator.
Neuropsychopharmacology
PUBLISHED: 11-30-2011
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Based on the glutamatergic hypothesis of schizophrenia we assessed the effects of a novel mGlu5 positive allosteric modulator, LSN2463359 [N-(1-methylethyl)-5-(pyridin-4-ylethynyl)pyridine-2-carboxamide] on deficits in cognitive flexibility in two distinct rodent models of schizophrenia, the neurodevelopmental MAM E17 model and the acute PCP model. Cognitive flexibility was measured with the intra-dimensional and extra-dimensional set-shifting and reversal learning digging paradigm. Regional effects of MAM on the expression of parvalbumin-positive cells (PV) and mGlu5 receptors were also examined, to further characterize the model. Results showed that LSN2463359 selectively attenuated reversal learning deficits in the MAM but not acute PCP model. Whilst both models led to deficits in reversal learning and extra-dimensional set-shifting, the reversal impairments were qualitatively distinct, with MAM increasing perseverative responding, whereas the PCP deficit was mainly due to the inability of rats to maintain reinforced choice behavior. Reduction of PV and mGlu5 expression was found in the MAM model in several regions of importance in schizophrenia, such as the orbitofrontal and medial prefrontal cortex, which also mediate reversal learning and extra-dimensional set-shifting. The present findings confirm that the positive modulation of mGlu5 receptors may have beneficial effects in the treatment of certain aspects of cognitive impairment associated with schizophrenia. This study also illustrates the importance of studying putative cognitive enhancing drug effects in a number of models which may have implications for the future development of the compound.
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Comparison of body mass index and triceps skinfold at 5 years and young adult body mass index, waist circumference and blood pressure.
J Paediatr Child Health
PUBLISHED: 11-16-2011
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To examine which measure of obesity at 5 years, body mass index (BMI) or triceps skinfold thickness, is most strongly associated with 21-year risk factors for cardiovascular disease (CVD), including BMI, waist circumference (WC), systolic blood pressure (SBP) and diastolic blood pressure (DBP).
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Generic comparison of protein inference engines.
Mol. Cell Proteomics
PUBLISHED: 11-04-2011
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Protein identifications, instead of peptide-spectrum matches, constitute the biologically relevant result of shotgun proteomics studies. How to appropriately infer and report protein identifications has triggered a still ongoing debate. This debate has so far suffered from the lack of appropriate performance measures that allow us to objectively assess protein inference approaches. This study describes an intuitive, generic and yet formal performance measure and demonstrates how it enables experimentalists to select an optimal protein inference strategy for a given collection of fragment ion spectra. We applied the performance measure to systematically explore the benefit of excluding possibly unreliable protein identifications, such as single-hit wonders. Therefore, we defined a family of protein inference engines by extending a simple inference engine by thousands of pruning variants, each excluding a different specified set of possibly unreliable identifications. We benchmarked these protein inference engines on several data sets representing different proteomes and mass spectrometry platforms. Optimally performing inference engines retained all high confidence spectral evidence, without posterior exclusion of any type of protein identifications. Despite the diversity of studied data sets consistently supporting this rule, other data sets might behave differently. In order to ensure maximal reliable proteome coverage for data sets arising in other studies we advocate abstaining from rigid protein inference rules, such as exclusion of single-hit wonders, and instead consider several protein inference approaches and assess these with respect to the presented performance measure in the specific application context.
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Junior doctors experiences of personal illness: a qualitative study.
Med Educ
PUBLISHED: 10-25-2011
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Professional status and working arrangements can inhibit doctors from acknowledging and seeking care for their own ill health. Research identifies that a culture of immunity to illness within the medical profession takes root during training. What happens when trainee doctors become unwell during their formative period of education and training? What support do they receive and how do they perceive that the experience of ill health affects their training trajectory? These research questions were developed by a multidisciplinary team of researchers and health professionals, who adopted a qualitative approach to investigate the experiences of personal illness among trainees in their Foundation Programme (FP) years.
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Tertiary interactions between helices h13 and h44 in 16S RNA contribute to the fidelity of translation.
FEBS J.
PUBLISHED: 10-17-2011
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The A-minor interaction, formed between single-stranded adenosines and the minor groove of a receptor helix, is among the most common motifs found in rRNA. Among the A-minors found in 16S rRNA are a set of interactions between adenosines at positions 1433, 1434 and 1468 in helix 44 (h44) and their receptors in the nucleotide 320-340 region of helix 13 (h13). These interactions have been implicated in the maintenance of translational accuracy, because base substitutions at the adjacent C1469 increase miscoding errors. We have tested their functional significance through mutagenesis of h13 and h44. Mutations at the h44 A residues, or the A-minor receptors in h13, increase a variety of translational errors and a subset of the mutants show decreased association between 30S and 50S ribosomal subunits. These results are consistent with the involvement of h13-h44 interactions in the alignment and packing of these helices in the 30S subunit and the importance of this helical alignment for tRNA selection and subunit-subunit interaction.
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Microtubule-associated protein 1 light chain 3 alpha (LC3)-associated phagocytosis is required for the efficient clearance of dead cells.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-03-2011
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The recognition and clearance of dead cells is a process that must occur efficiently to prevent an autoimmune or inflammatory response. Recently, a process was identified wherein the autophagy machinery is recruited to pathogen-containing phagosomes, termed MAPLC3A (LC3)-associated phagocytosis (LAP), which results in optimal degradation of the phagocytosed cargo. Here, we describe the engagement of LAP upon uptake of apoptotic, necrotic, and RIPK3-dependent necrotic cells by macrophages. This process is dependent on some members of the classical autophagy pathway, including Beclin1, ATG5, and ATG7. In contrast, ULK1, despite being required for autophagy, is dispensable for LAP induced by uptake of microbes or dead cells. LAP is required for efficient degradation of the engulfed corpse, and in the absence of LAP, engulfment of dead cells results in increased production of proinflammatory cytokines and decreased production of anti-inflammatory cytokines. LAP is triggered by engagement of the TIM4 receptor by either phosphatidylserine (PtdSer)-displaying dead cells or PtdSer-containing liposomes. Therefore, the consequence of phagocytosis of dead cells is strongly affected by those components of the autophagy pathway involved in LAP.
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The methylazoxymethanol acetate (MAM-E17) rat model: molecular and functional effects in the hippocampus.
Neuropsychopharmacology
PUBLISHED: 09-28-2011
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Administration of the DNA-alkylating agent methylazoxymethanol acetate (MAM) on embryonic day 17 (E17) produces behavioral and anatomical brain abnormalities, which model some aspects of schizophrenia. This has lead to the premise that MAM rats are a neurodevelopmental model for schizophrenia. However, the underlying molecular pathways affected in this model have not been elucidated. In this study, we investigated the molecular phenotype of adult MAM rats by focusing on the frontal cortex and hippocampal areas, as these are known to be affected in schizophrenia. Proteomic and metabonomic analyses showed that the MAM treatment on E17 resulted primarily in deficits in hippocampal glutamatergic neurotransmission, as seen in some schizophrenia patients. Most importantly, these results were consistent with our finding of functional deficits in glutamatergic neurotransmission, as identified using electrophysiological recordings. Thus, this study provides the first molecular evidence, combined with functional validation, that the MAM-E17 rat model reproduces hippocampal deficits relevant to the pathology of schizophrenia.
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Overweight and obesity knowledge prior to pregnancy: a survey study.
BMC Pregnancy Childbirth
PUBLISHED: 09-09-2011
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Overweight and obesity are associated with increased risk for pregnancy complications. Knowledge about increased risks in overweight and obese women could contribute to successful prevention strategies and the aim of this study is to assess current levels of knowledge in a pregnant population.
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Prevention of intraoperative awareness in a high-risk surgical population.
N. Engl. J. Med.
PUBLISHED: 08-19-2011
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Unintended intraoperative awareness, which occurs when general anesthesia is not achieved or maintained, affects up to 1% of patients at high risk for this complication. We tested the hypothesis that a protocol incorporating the electroencephalogram-derived bispectral index (BIS) is superior to a protocol incorporating standard monitoring of end-tidal anesthetic-agent concentration (ETAC) for the prevention of awareness.
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Passive immunization with anti-Tau antibodies in two transgenic models: reduction of Tau pathology and delay of disease progression.
J. Biol. Chem.
PUBLISHED: 08-12-2011
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The microtubule-associated protein Tau plays a critical role in the pathogenesis of Alzheimer disease and several related disorders (tauopathies). In the disease Tau aggregates and becomes hyperphosphorylated forming paired helical and straight filaments, which can further condense into higher order neurofibrillary tangles in neurons. The development of this pathology is consistently associated with progressive neuronal loss and cognitive decline. The identification of tractable therapeutic targets in this pathway has been challenging, and consequently very few clinical studies addressing Tau pathology are underway. Recent active immunization studies have raised the possibility of modulating Tau pathology by activating the immune system. Here we report for the first time on passive immunotherapy for Tau in two well established transgenic models of Tau pathogenesis. We show that peripheral administration of two antibodies against pathological Tau forms significantly reduces biochemical Tau pathology in the JNPL3 mouse model. We further demonstrate that peripheral administration of the same antibodies in the more rapidly progressive P301S tauopathy model not only reduces Tau pathology quantitated by biochemical assays and immunohistochemistry, but also significantly delays the onset of motor function decline and weight loss. This is accompanied by a reduction in neurospheroids, providing direct evidence of reduced neurodegeneration. Thus, passive immunotherapy is effective at preventing the buildup of intracellular Tau pathology, neurospheroids, and associated symptoms, although the exact mechanism remains uncertain. Tau immunotherapy should therefore be considered as a therapeutic approach for the treatment of Alzheimer disease and other tauopathies.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.