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Find video protocols related to scientific articles indexed in Pubmed.
Alignathon: a competitive assessment of whole-genome alignment methods.
Genome Res.
PUBLISHED: 10-01-2014
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Multiple sequence alignments (MSAs) are a prerequisite for a wide variety of evolutionary analyses. Published assessments and benchmark data sets for protein and, to a lesser extent, global nucleotide MSAs are available, but less effort has been made to establish benchmarks in the more general problem of whole-genome alignment (WGA). Using the same model as the successful Assemblathon competitions, we organized a competitive evaluation in which teams submitted their alignments and then assessments were performed collectively after all the submissions were received. Three data sets were used: Two were simulated and based on primate and mammalian phylogenies, and one was comprised of 20 real fly genomes. In total, 35 submissions were assessed, submitted by 10 teams using 12 different alignment pipelines. We found agreement between independent simulation-based and statistical assessments, indicating that there are substantial accuracy differences between contemporary alignment tools. We saw considerable differences in the alignment quality of differently annotated regions and found that few tools aligned the duplications analyzed. We found that many tools worked well at shorter evolutionary distances, but fewer performed competitively at longer distances. We provide all data sets, submissions, and assessment programs for further study and provide, as a resource for future benchmarking, a convenient repository of code and data for reproducing the simulation assessments.
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Effects of geometry and chemistry on hydrophobic solvation.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-25-2014
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Inserting an uncharged van der Waals (vdw) cavity into water disrupts the distribution of water and creates attractive dispersion interactions between the solvent and solute. This free-energy change is the hydrophobic solvation energy (?Gvdw). Frequently, it is assumed to be linear in the solvent-accessible surface area, with a positive surface tension (?) that is independent of the properties of the molecule. However, we found that ? for a set of alkanes differed from that for four configurations of decaalanine, and ? = -5 was negative for the decaalanines. These findings conflict with the notion that ?Gvdw favors smaller A. We broke ?Gvdw into the free energy required to exclude water from the vdw cavity (?Grep) and the free energy of forming the attractive interactions between the solute and solvent (?Gatt) and found that ? < 0 for the decaalanines because -?att > ?rep and ?att < 0. Additionally, ?att and ?rep for the alkanes differed from those for the decaalanines, implying that none of ?Gatt, ?Grep, and ?Gvdw can be computed with a constant surface tension. We also showed that ?Gatt could not be computed from either the initial or final water distributions, implying that this quantity is more difficult to compute than is sometimes assumed. Finally, we showed that each atom's contribution to ?rep depended on multibody interactions with its surrounding atoms, implying that these contributions are not additive. These findings call into question some hydrophobic models.
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Low leukotriene B4 receptor 1 (LTB4R1) leads to ALOX5 down-regulation at diagnosis of chronic myeloid leukemia.
Haematologica
PUBLISHED: 09-05-2014
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ALOX5 is implicated in chronic myeloid leukaemia development in mouse leukaemic stem cells, but its importance in human chronic myeloid leukaemia is unknown. Functional ALOX5 was assessed using an LTB4 ELISA and ALOX5 and LTB4R1 mRNA expression was determined via a TaqMan gene expression assay. LTB4R1 and 5-LOX protein levels were assessed by cell surface flow cytometry analysis. At diagnosis ALOX5 was below normal in both blood and CD34+ stem cells in all patients. On treatment initiation, ALOX5 levels increased in all patients except those who were destined to progress subsequently to blast crisis. LTB4 levels were increased despite low ALOX5 expression, suggesting that the arachidonic acid pathway is functioning normally up to the point of LTB4 production. However, the LTB4 receptor (BLT1) protein in newly diagnosed patients was significantly lower than after a period of treatment (p<0.0001). The low level of LTB4R1 at diagnosis explains the down-regulation of ALOX5. In the absence of LTB4R1, the arachidonic acid pathway intermediates (5-HEPTE and LTA4) negatively regulate ALOX5. ALOX5 regulation is aberrant in chronic myeloid leukaemia patients and may not be important for the development of the disease. Our data suggest caution when extrapolating mouse model data into human chronic myeloid leukaemia.
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Root Canal Therapy Reduces Multiple Dimensions of Pain: A National Dental Practice-based Research Network Study.
J Endod
PUBLISHED: 09-01-2014
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Initial orthograde root canal therapy (RCT) is used to treat dentoalveolar pathosis. The effect RCT has on pain intensity has been frequently reported, but the effect on other dimensions of pain has not. Also, the lack of large prospective studies involving diverse groups of patients and practitioners who are not involved in data collection suggest that there are multiple opportunities for bias to be introduced when these data are systematically aggregated.
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cprThe FGF21 analogue, LY2405319, lowers blood glucose in streptozotocin-induced insulin-deficient diabetic mice by restoring brown adipose tissue function.
Diabetes Obes Metab
PUBLISHED: 08-25-2014
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Fibroblast growth factor 21 (FGF21) has emerged as a promising therapeutic agent for the treatment of obesity and type 2 diabetes via improving insulin sensitivity. However, evidence for an effect of FGF21 on insulin-deficient Type 1 diabetes (T1DM) is lacking. Here, we investigated the effects of LY2405319, an analog of FGF21, on glucose homeostasis in streptozotocin-induced insulin-deficient mice (STZ mice).
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MondoA deficiency enhances sprint performance in mice.
Biochem. J.
PUBLISHED: 08-23-2014
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MondoA is a basic helix-loop-helix (bHLH)/leucine zipper (ZIP) transcription factor that is expressed predominantly in skeletal muscle. Studies in vitro suggest that the Max-like protein X (MondoA:Mlx) heterodimer senses the intracellular energy status and directly targets the promoter region of thioredoxin interacting protein (Txnip) and possibly glycolytic enzymes. We generated MondoA-inactivated (MondoA-/-) mice by gene targeting. MondoA-/- mice had normal body weight at birth, exhibited normal growth and appeared to be healthy. However, they exhibited unique metabolic characteristics. MondoA-/- mice built up serum lactate and alanine levels and utilized fatty acids for fuel during exercise. Gene expression and promoter analysis suggested that MondoA functionally represses peroxisome-proliferator-activated receptor ? co-activator-1? (PGC-1?)-mediated activation of pyruvate dehydrogenase kinase 4 (PDK-4) transcription. PDK4 normally down-regulates the activity of pyruvate dehydrogenase, an enzyme complex that catalyses the decarboxylation of pyruvate to acetyl-CoA for entry into the Krebs cycle; in the absence of MondoA, pyruvate is diverted towards lactate and alanine, both products of glycolysis. Dynamic testing revealed that MondoA-/- mice excel in sprinting as their skeletal muscles display an enhanced glycolytic capacity. Our studies uncover a hitherto unappreciated function of MondoA in fuel selection in vivo. Lack of MondoA results in enhanced exercise capacity with sprinting.
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Kinetics and mechanism of the racemization of aryl allenes catalyzed by cationic gold(I) phosphine complexes.
Chemistry
PUBLISHED: 08-08-2014
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The kinetics of the racemization of aromatic 1,3-disubstituted allenes catalyzed by gold phosphine complexes has been investigated. The rate of gold-catalyzed allene racemization displayed first-order dependence on allene, and catalyst concentration and kinetic analysis of gold-catalyzed allene racemization as a function of allene and phosphine electron-donor ability established the accumulation of electron density on the phosphine atom and the depletion of electron density on the terminal allenyl carbon atoms in the rate-limiting transition state for racemization. These and other observations were in accord with a mechanism for allene racemization involving rapid and reversible inter- and intramolecular allene exchange followed by turnover-limiting, unimolecular conversion of a chiral gold ?(2)-allene complex to an achiral ?(1)-allylic cation intermediate through a bent and twisted ?(1)-allene transition state. With respect to proper ligand selection, these studies reveal that both electron-poor phosphine ligands and polar solvents facilitate racemization.
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Analysis of Three-Dimensional Aerosol Deposition in Pharmacologically Relevant Terms: Beyond Black or White ROIs.
J Aerosol Med Pulm Drug Deliv
PUBLISHED: 07-23-2014
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Abstract Background: This article presents a novel methodological approach to evaluate images of aerosol deposition taken with PET-CT cameras. Traditionally, Black-or-White (BW) Regions of Interest (ROIs) are created to cover Anatomical Regions (ARs) segmented from the high-resolution CT. Such ROIs do not usually consider blurring effects due to limited spatial resolution or breathing motion, and do not consider uncertainty in the AR position within the PET image. The new methodology presented here (Grayscale) addresses these issues, allows estimates of aerosol deposition within ARs, and expresses the deposition in terms of Tissue Dosing (in the lung periphery) and Inner Surface Concentration (in the larger airways). Methods: Imaging data included a PET deposition image acquired during breathing and two CT scans acquired during breath holds at different lung volumes. The lungs were segmented into anatomically consistent ARs to allow unbiased comparisons across subjects and across lobes. The Grayscale method involves defining Voxel Influence Matrices (VIMs) to consider how average activity within each AR influences the measured activity within each voxel. The BW and Grayscale methods were used to analyze aerosol deposition in 14 bronchoconstricted asthmatics. Results: Grayscale resulted in a closer description of the PET image than BW (p<0.0001) and exposed a seven-fold underestimation in measures of specific deposition. The Average Tissue Dosing was 2.11×10(-6) Total Lung Dose/mg. The average Inner Surface Concentration was 45×10(-6) Total Lung Dose/mm(2), with the left lower lobe having a lower ISC than lobes of the right lung (p<0.05). There was a strong lobar heterogeneity in these measures (COV=0.3). Conclusion: The Grayscale approach is an improvement over the BW approach and provides a closer description of the PET image. It can be used to characterize heterogeneous concentrations throughout the lung and may be important in translational research and in the evaluation of aerosol delivery systems.
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Injuries of the Head from Backface Deformation of Ballistic Protective Helmets Under Ballistic Impact.
J. Forensic Sci.
PUBLISHED: 07-22-2014
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Modern ballistic helmets defeat penetrating bullets by energy transfer from the projectile to the helmet, producing helmet deformation. This deformation may cause severe injuries without completely perforating the helmet, termed "behind armor blunt trauma" (BABT). As helmets become lighter, the likelihood of larger helmet backface deformation under ballistic impact increases. To characterize the potential for BABT, seven postmortem human head/neck specimens wearing a ballistic protective helmet were exposed to nonperforating impact, using a 9 mm, full metal jacket, 124 grain bullet with velocities of 400-460 m/s. An increasing trend of injury severity was observed, ranging from simple linear fractures to combinations of linear and depressed fractures. Overall, the ability to identify skull fractures resulting from BABT can be used in forensic investigations. Our results demonstrate a high risk of skull fracture due to BABT and necessitate the prevention of BABT as a design factor in future generations of protective gear.
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Synergy of silver nanoparticles and aztreonam against Pseudomonas aeruginosa PAO1 biofilms.
Antimicrob. Agents Chemother.
PUBLISHED: 07-21-2014
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Pathogenic bacterial biofilms, such as those found in the lungs of patients with cystic fibrosis (CF), exhibit increased antimicrobial resistance, due in part to the inherent architecture of the biofilm community. The protection provided by the biofilm limits antimicrobial dispersion and penetration and reduces the efficacy of antibiotics that normally inhibit planktonic cell growth. Thus, alternative antimicrobial strategies are required to combat persistent infections. The antimicrobial properties of silver have been known for decades, but silver and silver-containing compounds have recently seen renewed interest as antimicrobial agents for treating bacterial infections. The goal of this study was to assess the efficacy of citrate-capped silver nanoparticles (AgNPs) of various sizes, alone and in combination with the monobactam antibiotic aztreonam, to inhibit Pseudomonas aeruginosa PAO1 biofilms. Among the different sizes of AgNPs examined, 10-nm nanoparticles were most effective in inhibiting the recovery of P. aeruginosa biofilm cultures and showed synergy of inhibition when combined with sub-MIC levels of aztreonam. Visualization of biofilms treated with combinations of 10-nm AgNPs and aztreonam indicated that the synergistic bactericidal effects are likely caused by better penetration of the small AgNPs into the biofilm matrix, which enhances the deleterious effects of aztreonam against the cell envelope of P. aeruginosa within the biofilms. These data suggest that small AgNPs synergistically enhance the antimicrobial effects of aztreonam against P. aeruginosa in vitro, and they reveal a potential role for combinations of small AgNPs and antibiotics in treating patients with chronic infections.
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Short communication: kidney dysfunction among HIV-infected children in Latin America and the Caribbean.
AIDS Res. Hum. Retroviruses
PUBLISHED: 07-16-2014
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Renal toxicity is a concern in HIV-infected children receiving antiretrovirals. However, the prevalence [1.7%; 95% confidence interval (CI): 1.0-2.6%] and incidence of kidney dysfunction (0.17 cases/100 person-years; 95% CI: 0.04-0.30) were rare in this multicenter cohort study of 1,032 perinatally HIV-infected Latin American and Caribbean children followed from 2002 to 2011.
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Exploration of the Effect of Tobacco Smoking on Metabolic Measures in Young People Living with HIV.
AIDS Res Treat
PUBLISHED: 07-09-2014
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We conducted cross-sectional, multicenter studies in HIV-positive young women and men to assess metabolic and morphologic complications from tobacco smoking in 372 behaviorally infected HIV-positive youth, aged 14-25 years. Measurements included self-reported tobacco use, fasting lipids, glucose, fat distribution, and bone mineral density (BMD; dual-energy X-ray absorptiometry scans). Overall, 144 (38.7%) self-reported smoking tobacco and 69 (47.9%) of these reported smoking greater than five cigarettes per day. Smokers versus nonsmokers had lower mean total cholesterol (146.0 versus 156.1?mg/dL; P < 0.01) and lower mean total body fat percent (24.1% versus 27.2%, P = 0.03). There was no difference between smokers and nonsmokers in fasting glucose or BMD. There appear to be only minimal effects from tobacco smoking on markers of cardiac risk and bone health in this population of HIV-positive youth. While these smokers may not have had sufficient exposure to tobacco to detect changes in the outcome measures, given the long-term risks associated with smoking and HIV, it is critical that we encourage HIV-positive youth smokers to quit before the deleterious effects become apparent.
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Adoptive transfer of cytokine-induced immunomodulatory adult microglia attenuates experimental autoimmune encephalomyelitis in DBA/1 mice.
Glia
PUBLISHED: 07-08-2014
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Microglia are resident antigen-presenting cells in the central nervous system (CNS) that either suppress or promote disease depending on their activation phenotype and the microenvironment. Multiple sclerosis (MS) is a chronic inflammatory disease causing demyelination and nerve loss in the CNS, and experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that is widely used to investigate pathogenic mechanisms and therapeutic effects. We isolated and cultured microglia from adult mouse brains and exposed them to specific combinations of stimulatory molecules and cytokines, the combination of IL-4, IL-10, and TGF-? yielding the optimal regime for induction of an immunosuppressive phenotype (M2). M2 microglia were characterized by decreased expression or production of CD86, PD-L1, nitric oxide, and IL-6, increased expression of PD-L2, and having a potent capacity to retain their phenotype on secondary proinflammatory stimulation. M2 microglia induced regulatory T cells, suppressed T-cell proliferation, and downmodulated M1-associated receptor expression in M1 macrophages. Myelin oligodendrocyte glycoprotein (MOG)-induced EAE was induced in DBA/1 mice and at different time points (0, 5, 12, or 15 days postimmunization) 3 × 105 M2 microglia were transferred intranasally. A single transfer of M2 microglia attenuated the severity of established EAE, which was particularly obvious when the cells were injected at 15 days postimmunization. M2 microglia-treated mice had reduced inflammatory responses and less demyelination in the CNS. Our findings demonstrate that adult M2 microglia therapy represents a novel intervention that alleviated established EAE and that this therapeutic principle may have relevance for treatment of MS patients.
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Measuring chirality in NMR in the presence of a time-dependent electric field.
J Chem Phys
PUBLISHED: 06-23-2014
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Traditional nuclear magnetic resonance (NMR) experiments are "blind" to chirality since the spectra for left and right handed enantiomers are identical in an achiral medium. However, theoretical arguments have suggested that the effective Hamiltonian for spin-1/2 nuclei in the presence of electric and magnetic fields can be different for left and right handed enantiomers, thereby enabling NMR to be used to spectroscopically detect chirality even in an achiral medium. However, most proposals to detect the chiral NMR signature require measuring signals that are equivalent to picomolar concentrations for (1)H nuclei, which are outside current NMR detection limits. In this work, we propose to use an AC electric field that is resonantly modulated at the Larmor frequency, thereby enhancing the effect of the chiral term by four to six orders of magnitude. We predict that a steady-state transverse magnetization, whose direction will be opposite for different enantiomers, will build up during application of an AC electric field. We also propose an experimental setup that uses a solenoid coil with an AC current to generate the necessary periodic electric fields that can be used to generate chiral signals which are equivalent to the signal from a (1)H submicromolar concentration.
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Effects of calcium carbonate, sevelamer hydrochloride or pantoprazole on the pharmacokinetics of cinacalcet.
Clin Drug Investig
PUBLISHED: 06-18-2014
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Secondary hyperparathyroidism is a common consequence of chronic kidney disease. Cinacalcet (Sensipar(®)) is often prescribed in combination to reduce elevated levels of parathyroid hormone, calcium and phosphorus. The objective of this study was to assess the effects of concomitantly administered therapies of calcium carbonate (CaCO(3); TUMS(®)), sevelamer hydrochloride (HCl; Renagel(®)) and pantoprazole sodium (Protonix(®)) on the pharmacokinetics and safety of cinacalcet in healthy subjects.
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Aluminium electrodeposition under ambient conditions.
Phys Chem Chem Phys
PUBLISHED: 06-12-2014
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The electrodeposition of aluminium is demonstrated using a eutectic mixture of aluminium chloride and urea. The mixture is shown to be conducting through the formation of both cationic ([AlCl2·urean](+)) and anionic (AlCl4(-)) species and electrodeposition is achieved through the cationic species. The use of a biphasic system with the ionic liquid and a protective hydrocarbon layer allows metal deposition to be carried out in an environment with ambient moisture without the need for a glove box. A direct comparison is made between the AlCl3:urea and imidazolium chloride:AlCl3 systems and the differences in speciation and mass transport manifest themselves in different deposit morphologies. Brighteners which work in the chloroaluminate system such as toluene and LiCl are shown to be ineffective in the urea based system and the reasons for these differences are ascribed to the mechanism of the anodic reaction which is rate limiting.
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Cochlear implantation in a patient with combined renal and liver transplantation.
Cochlear Implants Int
PUBLISHED: 05-20-2014
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Objective and importance Patients who have undergone solid organ transplantation and continuing immunosuppressant medication are at a higher risk of wound problems and infections following cochlear implantation. This risk is theoretically even further increased in multi-organ transplant recipients due to the increased doses of immunosuppressive medications that these patients are administered. Clinical presentation and intervention Here, we present the first reported case of successful cochlear implantation in a patient who had previously undergone successful combined liver and kidney transplant. She had no significant complications from the surgery and had good audiological outcomes 3 months post-operatively. Conclusion As we continue our advances in the use of cochlear implant technology, our report adds to the growing evidence of its benefits in transplant recipients. However, there are important pre- and peri-operative considerations in this group of patients which can improve safety and outcome.
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Implementing asthma guidelines using practice facilitation and local learning collaboratives: a randomized controlled trial.
Ann Fam Med
PUBLISHED: 05-14-2014
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Guideline implementation in primary care has proven difficult. Although external assistance through performance feedback, academic detailing, practice facilitation (PF), and learning collaboratives seems to help, the best combination of interventions has not been determined.
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Retinoic acid-related orphan receptor alpha reprograms glucose metabolism in glutamine-deficient hepatoma cells.
Hepatology
PUBLISHED: 05-08-2014
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The metabolism of glutamine and glucose is recognized as a promising therapeutic target for the treatment of cancer; however, targeted molecule that mediate glutamine and glucose metabolism in cancer cells has not been addressed. Here, we show that restricting the supply of glutamine in hepatoma cells, including HepG2 and Hep3B cells, markedly increased the expression of retinoic acid-related orphan receptor (ROR) ?. Up-regulation of ROR? in glutamine-deficient hepatoma cells resulted from an increase in the level of cellular reactive oxygen species and in the NADP(+) /NADPH ratio, which was consistent with a reduction in the GSH/GSSG ratio. Adenovirus-mediated overexpression of ROR? (Ad-ROR?) or treatment with the ROR? activator, SR1078, reduced aerobic glycolysis and down-regulated biosynthetic pathways in hepatoma cells. Ad-ROR? and SR1078 reduced the expression of pyruvate dehydrogenase kinase 2 (PDK2) and inhibited the phosphorylation of PDHe1?, subsequently shifted pyruvate to complete oxidation. The ROR?-mediated decrease in PDK2 levels was caused by up-regulation of p21 rather than p53. Furthermore, ROR? inhibited hepatoma growth both in vitro and in a xenograft model in vivo. We also found that suppression of PDK2 inhibited hepatoma growth in a xenograft model. These findings mimic the altered glucose utilization and hepatoma growth caused by glutamine deprivation. Finally, tumor tissue from 187 hepatocellular carcinoma patients expressed lower levels of ROR? than adjacent non-tumor tissue, supporting a potential beneficial effect of ROR? activation in the treatment of liver cancer. Conclusion: The data reported herein show that ROR? mediates reprogramming of glucose metabolism in hepatoma cells in response to glutamine deficiency. The relationships established here between glutamine metabolism, ROR? expression and signaling, and aerobic glycolysis have implications for therapeutic targeting of liver cancer metabolism. (Hepatology 2014).
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Synthesis, structure, and reactivity of a gold carbenoid complex that lacks heteroatom stabilization.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 05-01-2014
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Hydride abstraction from the neutral gold cycloheptatrienyl complex [(P)Au(?(1)-C7H7)] (P=P(tBu)2(o-biphenyl)) with triphenylcarbenium tetrafluoroborate at -80?°C led to the isolation of the cationic gold cycloheptatrienylidene complex [(P)Au(?(1)-C7H6)](+) BF4(-) in 52% yield, which was characterized in solution and by single-crystal X-ray diffraction. This cycloheptatrienylidene complex represents the first example of a gold carbenoid complex that lacks conjugated heteroatom stabilization of the electron-deficient C1 carbon atom. The cycloheptatrienylidene ligand of this complex is reactive; it can be reduced by mild hydride donors, and converted to tropone in the presence of pyridine N-oxide.
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HECTOR: a parallel multistage homopolymer spectrum based error corrector for 454 sequencing data.
BMC Bioinformatics
PUBLISHED: 04-24-2014
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Current-generation sequencing technologies are able to produce low-cost, high-throughput reads. However, the produced reads are imperfect and may contain various sequencing errors. Although many error correction methods have been developed in recent years, none explicitly targets homopolymer-length errors in the 454 sequencing reads.
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Speciation, physical and electrolytic properties of eutectic mixtures based on CrCl?·6H?O and urea.
Phys Chem Chem Phys
PUBLISHED: 04-04-2014
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The electrodeposition of chromium is a technologically vital process, which is principally carried out using aqueous chromic acid. In the current study, it is shown that eutectic mixtures of urea and hydrated chromium(III) chloride provide a liquid which reduces the toxicological issues associated with the current aqueous Cr(VI) electroplating solution. Using EXAFS, mass spectrometry and UV-Vis spectroscopy, it is shown that chromium is present predominantly as a cationic species. Conductivities are higher than for most comparable ionic liquids. It is shown that the electrodeposition of chromium is electrochemically reversible, with a current efficiency much higher than in aqueous electrolytes. Surface tension and density measurements indicate that hole theory is a valid model to describe transport properties in these liquids. Bulk Cr deposits are not macrocrystalline but they are generally crack-free. The deposits have a hardness of 600 ± 10 Vickers and, as such, are comparable to deposits from aqueous systems.
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Amino acid misincorporation in recombinant biopharmaceutical products.
Curr. Opin. Biotechnol.
PUBLISHED: 04-02-2014
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Microbial and mammalian host systems have been used extensively for the production of protein biotherapeutics. Generally these systems rely on the production of a specific gene sequence encoding one therapeutic product. Analysis of these protein products over many years has proven that this was not always the case, with multiple species of the intended product being produced due to amino acid misincorporation or mistranslation during biosynthesis of the protein. This review is the first to give a comprehensive overview of the occurrence and analysis of these misincorporations. Furthermore, using the latest data on misincorporation in native human proteins we explore potential considerations for producing a specification for misincorporation for the development of a human biotherapeutic protein product in a production environment.
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Tuberculosis in HIV-infected infants, children, and adolescents in Latin America.
Braz J Infect Dis
PUBLISHED: 03-11-2014
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To evaluate the occurrence, clinical presentations and diagnostic methods for tuberculosis in a cohort of HIV-infected infants, children and adolescents from Latin America.
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A novel radiotracer to image glycogen metabolism in tumors by positron emission tomography.
Cancer Res.
PUBLISHED: 03-05-2014
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The high rate of glucose uptake to fuel the bioenergetic and anabolic demands of proliferating cancer cells is well recognized and is exploited with (18)F-2-fluoro-2-deoxy-d-glucose positron emission tomography ((18)F-FDG-PET) to image tumors clinically. In contrast, enhanced glucose storage as glycogen (glycogenesis) in cancer is less well understood and the availability of a noninvasive method to image glycogen in vivo could provide important biologic insights. Here, we demonstrate that (18)F-N-(methyl-(2-fluoroethyl)-1H-[1,2,3]triazole-4-yl)glucosamine ((18)F-NFTG) annotates glycogenesis in cancer cells and tumors in vivo, measured by PET. Specificity of glycogen labeling was demonstrated by isolating (18)F-NFTG-associated glycogen and with stable knockdown of glycogen synthase 1, which inhibited (18)F-NFTG uptake, whereas oncogene (Rab25) activation-associated glycogen synthesis led to increased uptake. We further show that the rate of glycogenesis is cell-cycle regulated, enhanced during the nonproliferative state of cancer cells. We demonstrate that glycogen levels, (18)F-NFTG, but not (18)F-FDG uptake, increase proportionally with cell density and G1-G0 arrest, with potential application in the assessment of activation of oncogenic pathways related to glycogenesis and the detection of posttreatment tumor quiescence.
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Sensitivities to parameterization in the size-modified Poisson-Boltzmann equation.
J Chem Phys
PUBLISHED: 02-25-2014
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Experimental results have demonstrated that the numbers of counterions surrounding nucleic acids differ from those predicted by the nonlinear Poisson-Boltzmann equation, NLPBE. Some studies have fit these data against the ion size in the size-modified Poisson-Boltzmann equation, SMPBE, but the present study demonstrates that other parameters, such as the Stern layer thickness and the molecular surface definition, can change the number of bound ions by amounts comparable to varying the ion size. These parameters will therefore have to be fit simultaneously against experimental data. In addition, the data presented here demonstrate that the derivative, SK, of the electrostatic binding free energy, ?Gel, with respect to the logarithm of the salt concentration is sensitive to these parameters, and experimental measurements of SK could be used to parameterize the model. However, although better values for the Stern layer thickness and ion size and better molecular surface definitions could improve the model's predictions of the numbers of ions around biomolecules and SK, ?Gel itself is more sensitive to parameters, such as the interior dielectric constant, which in turn do not significantly affect the distributions of ions around biomolecules. Therefore, improved estimates of the ion size and Stern layer thickness to use in the SMPBE will not necessarily improve the model's predictions of ?Gel.
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Intranasal delivery of central nervous system-retargeted human mesenchymal stromal cells prolongs treatment efficacy of experimental autoimmune encephalomyelitis.
Immunology
PUBLISHED: 02-17-2014
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Treatment with mesenchymal stromal cells (MSCs) is currently of interest for a number of diseases including multiple sclerosis. MSCs are known to target inflamed tissues, but in a therapeutic setting their systemic administration will lead to few cells reaching the brain. We hypothesized that MSCs may target the brain upon intranasal administration and persist in central nervous system (CNS) tissue if expressing a CNS-targeting receptor. To demonstrate proof of concept, MSCs were genetically engineered to express a myelin oligodendrocyte glycoprotein-specific receptor. Engineered MSCs retained their immunosuppressive capacity, infiltrated into the brain upon intranasal cell administration, and were able to significantly reduce disease symptoms of experimental autoimmune encephalomyelitis (EAE). Mice treated with CNS-targeting MSCs were resistant to further EAE induction whereas non-targeted MSCs did not give such persistent effects. Histological analysis revealed increased brain restoration in engineered MSC-treated mice. In conclusion, MSCs can be genetically engineered to target the brain and prolong therapeutic efficacy in an EAE model.
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Recurrent glioblastoma treated with bevacizumab: contrast-enhanced T1-weighted subtraction maps improve tumor delineation and aid prediction of survival in a multicenter clinical trial.
Radiology
PUBLISHED: 01-31-2014
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To compare the capability to aid prediction of clinical outcome measures, including progression-free survival (PFS) and overall survival (OS), between volumetric estimates from contrast material-enhanced (CE) T1-weighted subtraction maps and traditional segmentation in a randomized multicenter clinical trial of recurrent glioblastoma (GBM) patients treated with bevacizumab.
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Cerebral activations related to audition-driven performance imagery in professional musicians.
PLoS ONE
PUBLISHED: 01-01-2014
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Functional Magnetic Resonance Imaging (fMRI) was used to study the activation of cerebral motor networks during auditory perception of music in professional keyboard musicians (n?=?12). The activation paradigm implied that subjects listened to two-part polyphonic music, while either critically appraising the performance or imagining they were performing themselves. Two-part polyphonic audition and bimanual motor imagery circumvented a hemisphere bias associated with the convention of playing the melody with the right hand. Both tasks activated ventral premotor and auditory cortices, bilaterally, and the right anterior parietal cortex, when contrasted to 12 musically unskilled controls. Although left ventral premotor activation was increased during imagery (compared to judgment), bilateral dorsal premotor and right posterior-superior parietal activations were quite unique to motor imagery. The latter suggests that musicians not only recruited their manual motor repertoire but also performed a spatial transformation from the vertically perceived pitch axis (high and low sound) to the horizontal axis of the keyboard. Imagery-specific activations in controls were seen in left dorsal parietal-premotor and supplementary motor cortices. Although these activations were less strong compared to musicians, this overlapping distribution indicated the recruitment of a general 'mirror-neuron' circuitry. These two levels of sensori-motor transformations point towards common principles by which the brain organizes audition-driven music performance and visually guided task performance.
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Solvation free energies of alanine peptides: the effect of flexibility.
J Phys Chem B
PUBLISHED: 12-13-2013
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The electrostatic (?Gel), van der Waals cavity-formation (?Gvdw), and total (?G) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with fixed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ?Gel, and components ?Gvdw, and ?G, were found to be linear in n, with the slopes of the best-fit lines being ?el, ?vdw, and ?, respectively. Both ?el and ? were negative for fixed and flexible peptides, and ?vdw was negative for fixed peptides. That ?vdw was negative was surprising, as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that ?vdw should be positive. A negative ?vdw seemingly contradicts the notion that ?Gvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas. When we computed ?Gvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, ?vdw was positive. Because most proteins do not assume extended conformations, a ?Gvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We find few intramolecular H-bonds but show that the intramolecular van der Waals interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis. The large fluctuations in the vdw energy may make attributing the collapse of the peptide to this intramolecular energy difficult.
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Increased sensitivity to radiochemotherapy in IDH1 mutant glioblastoma as demonstrated by serial quantitative MR volumetry.
Neuro-oncology
PUBLISHED: 12-04-2013
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BackgroundIsocitrate dehydrogenase 1 (IDH1) mutations have been linked to favorable outcomes in patients with glioblastoma multiforme (GBM). Recent in vitro experiments suggest that IDH1 mutation sensitizes tumors to radiation damage. We hypothesized that radiographic treatment response would be significantly different between IDH1 mutant versus wild-type GBMs after radiotherapy (RT) and concurrent temozolomide (TMZ).MethodsA total of 39 newly diagnosed GBM patients with known IDH1 mutational status (10 IDH1 mutants), who followed standard therapy and had regular post-contrast T1W (T1+C) and T2W/ fluid-attenuated inversion recovery (FLAIR) images in the 6-month period after starting RT, were enrolled. The volume of contrast-enhancing and FLAIR hyperintensity were calculated from each scan. Linear and polynomial regression techniques were used to estimate the rate of change and temporal patterns in tumor volumes.ResultsIDH1 mutant GBMs demonstrated a favorable response to RT/TMZ in the study period, as demonstrated by 10 of 10 mutants showing radiographic response (decreasing VT1+C), compared with 13 of 29 wild-types (P < .001). During the study period, VT1+C and VFLAIR changed at -3.6% per week and +0.6% per week in IDH1 mutant tumors, respectively, as compared with +0.8% per week and +5.2% per week in IDH1 wild-type tumors (P = .0076 and P = .0118, respectively). Amongst the radiographic responders, IDH1 mutant GBMs still demonstrated significant progression-free and overall survival benefit. Aggregated tumor kinetics by group showed significant lower rate in IDH1 mutant GBMs in specific periods: >105 days for VFLAIR and 95-120 and >150 days for VT1+C from starting RT/TMZ.ConclusionsThe current study supports the hypothesis that IDH1 mutant GBMs are more sensitive to radiochemotherapy than IDH1 wild-type GBMs.
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Pyruvate Dehydrogenase Kinase-4 Contributes to the Recirculation of Gluconeogenic Precursors During Post-Exercise Glycogen Recovery.
Am. J. Physiol. Regul. Integr. Comp. Physiol.
PUBLISHED: 12-04-2013
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During recovery from glycogen-depleting exercise, there is a shift from carbohydrate oxidation to glycogen resynthesis. The activity of the pyruvate dehydrogenase (PDH) complex therefore may decrease to reduce oxidation of carbohydrates in favour of increasing gluconeogenic recycling of carbohydrate-derived substrates. The mechanism behind this has yet to be elucidated, however research examining mRNA content has suggested the less-abundant PDH kinase 4 (PDK4) may reduce PDH activation during exercise recovery. To investigate this, skeletal muscle and liver of wild-type (WT) and PDK4-knockout (PDK4-KO) mice were analyzed at rest (Rest), after exercise to exhaustion (Exh), and after two-hours of recovery with ad libitum feeding (Rec). Although there were no differences in exercise tolerance between genotypes, caloric consumption was doubled by PDK4-KO mice during Rec. Due to this, PDK4-KO mice at Rec supercompensated muscle glycogen to 120% of resting stores. Therefore an extra group of PDK4-KO mice were pair-fed (PF) with WT mice during Rec for comparison. PF mice fully replenished muscle glycogen but recovered only 50% of liver glycogen stores. Concentrations of muscle lactate and alanine were also lower in PF than in WT mice indicating that this decrease may lead to a potential reduction of recycled gluconeogenic substrates, due to oxidation of their carbohydrate precursors in skeletal muscle, leading to observed reductions in hepatic glucose and glycogen concentrations. Due to the impairments seen in PF PDK4-KO mice, these results suggest a role for PDK4 in regulating the PDH complex in muscle and promoting gluconeogenic precursor recirculation during recovery from exhaustive exercise.
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High coating of Ru(ii) complexes on gold nanoparticles for single particle luminescence imaging in cells.
Chem. Commun. (Camb.)
PUBLISHED: 11-26-2013
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Gold nanoparticles are efficiently labelled with a luminescent ruthenium complex, producing 13 and 100 nm diameter, monodisperse red-emissive imaging probes with luminescence lifetimes prolonged over the molecular unit. Single, 100 nm particles are observed in whole cell luminescence imaging which reveals their biomolecular association with chromatin in the nucleus of cancer cells.
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ACR Appropriateness Criteria® Second and Third Trimester Bleeding.
Ultrasound Q
PUBLISHED: 11-23-2013
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Vaginal bleeding occurring in the second or third trimesters of pregnancy can variably affect perinatal outcome, depending on whether it is minor (i.e. a single, mild episode) or major (heavy bleeding or multiple episodes.) Ultrasound is used to evaluate these patients. Sonographic findings may range from marginal subchorionic hematoma to placental abruption. Abnormal placentations such as placenta previa, placenta accreta and vasa previa require accurate diagnosis for clinical management. In cases of placenta accreta, magnetic resonance imaging is useful as an adjunct to ultrasound and is often appropriate for evaluation of the extent of placental invasiveness and potential involvement of adjacent structures. MRI is useful for preplanning for cases of complex delivery, which may necessitate a multi-disciplinary approach for optimal care.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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Image quality in real-time teleultrasound of infant hip exam over low-bandwidth internet links: a transatlantic feasibility study.
J Digit Imaging
PUBLISHED: 09-21-2013
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Evolution of communication systems, especially internet-based technologies, has probably affected Radiology more than any other medical specialty. Tremendous increase in internet bandwidth has enabled a true revolution in image transmission and easy remote viewing of the static images and real-time video stream. Previous reports of real-time telesonography, such as the ones developed for emergency situations and humanitarian work, rely on high compressions of images utilized by remote sonologist to guide and supervise the unexperienced examiner. We believe that remote sonology could be also utilized in teleultrasound exam of infant hip. We tested feasibility of a low-cost teleultrasound system for infant hip and performed data analysis on the transmitted and original images. Transmission of data was accomplished with Remote Ultrasound (RU), a software package specifically designed for teleultrasound transmission through limited internet bandwidth. While image analysis of image pairs revealed statistically significant loss of information, panel evaluation failed to recognize any clinical difference between the original saved and transmitted still images.
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General control nonderepressible 2 (GCN2) kinase protects oligodendrocytes and white matter during branched-chain amino acid deficiency in mice.
J. Biol. Chem.
PUBLISHED: 09-09-2013
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Branched-chain amino acid (BCAA) catabolism is regulated by branched-chain ?-keto acid dehydrogenase, an enzyme complex that is inhibited when phosphorylated by its kinase (BDK). Loss of BDK function in mice and humans causes BCAA deficiency and epilepsy with autistic features. In response to amino acid deficiency, phosphorylation of eukaryotic initiation factor 2? (eIF2?P) by general control nonderepressible 2 (GCN2) activates the amino acid stress response. We hypothesized that GCN2 functions to protect the brain during chronic BCAA deficiency. To test this idea, we generated mice lacking both Gcn2 and Bdk (GBDK) and examined the development of progeny. GBDK mice appeared normal at birth, but they soon stopped growing, developed severe ataxia, tremor, and anorexia, and died by postnatal day 15. BCAA levels in brain were diminished in both Bdk(-/-) and GBDK pups. Brains from Bdk(-/-) pups exhibited robust eIF2?P and amino acid stress response induction, whereas these responses were absent in GBDK mouse brains. Instead, myelin deficiency and diminished expression of myelin basic protein were noted in GBDK brains. Genetic markers of oligodendrocytes and astrocytes were also reduced in GBDK brains in association with apoptotic cell death in white matter regions of the brain. GBDK brains further demonstrated reduced Sod2 and Cat mRNA and increased Tnf? mRNA expression. The data are consistent with the idea that loss of GCN2 during BCAA deficiency compromises glial cell defenses to oxidative and inflammatory stress. We conclude that GCN2 protects the brain from developing a lethal leukodystrophy in response to amino acid deficiencies.
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Influence of Grid Spacing in Poisson-Boltzmann Equation Binding Energy Estimation.
J Chem Theory Comput
PUBLISHED: 09-03-2013
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Grid-based solvers of the Poisson-Boltzmann, PB, equation are routinely used to estimate electrostatic binding, ??Gel, and solvation, ?Gel, free energies. The accuracies of such estimates are subject to grid discretization errors from the finite difference approximation to the PB equation. Here, we show that the grid discretization errors in ??Gel are more significant than those in ?Gel, and can be divided into two parts: (i) errors associated with the relative positioning of the grid and (ii) systematic errors associated with grid spacing. The systematic error in particular is significant for methods, such as the molecular mechanics PB surface area, MM-PBSA, approach that predict electrostatic binding free energies by averaging over an ensemble of molecular conformations. Although averaging over multiple conformations can control for the error associated with grid placement, it will not eliminate the systematic error, which can only be controlled by reducing grid spacing. The present study indicates that the widely-used grid spacing of 0.5 Å produces unacceptable errors in ??Gel, even though its predictions of ?Gel are adequate for the cases considered here. Although both grid discretization errors generally increase with grid spacing, the relative sizes of these errors differ according to the solute-solvent dielectric boundary definition. The grid discretization errors are generally smaller on the Gaussian surface used in the present study than on either the solvent-excluded or van der Waals surfaces, which both contain more surface discontinuities (e.g., sharp edges and cusps). Additionally, all three molecular surfaces converge to very different estimates of ??Gel.
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A genome-wide association study identifies multiple susceptibility loci for chronic lymphocytic leukemia.
Nat. Genet.
PUBLISHED: 08-20-2013
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Genome-wide association studies (GWAS) of chronic lymphocytic leukemia (CLL) have shown that common genetic variation contributes to the heritable risk of CLL. To identify additional CLL susceptibility loci, we conducted a GWAS and performed a meta-analysis with a published GWAS totaling 1,739 individuals with CLL (cases) and 5,199 controls with validation in an additional 1,144 cases and 3,151 controls. A combined analysis identified new susceptibility loci mapping to 3q26.2 (rs10936599, P = 1.74 × 10(-9)), 4q26 (rs6858698, P = 3.07 × 10(-9)), 6q25.2 (IPCEF1, rs2236256, P = 1.50 × 10(-10)) and 7q31.33 (POT1, rs17246404, P = 3.40 × 10(-8)). Additionally, we identified a promising association at 5p15.33 (CLPTM1L, rs31490, P = 1.72 × 10(-7)) and validated recently reported putative associations at 5p15.33 (TERT, rs10069690, P = 1.12 × 10(-10)) and 8q22.3 (rs2511714, P = 2.90 × 10(-9)). These findings provide further insights into the genetic and biological basis of inherited genetic susceptibility to CLL.
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Polychromatic angiography for the assessment of VEGF-induced BRB dysfunction in the rabbit retina.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 07-25-2013
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To determine the utility of polychromatic angiography (PCA) in the assessment of VEGF-induced blood retinal barrier (BRB) dysfunction in rabbits.
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ACR Appropriateness Criteria® growth disturbances - risk of intrauterine growth restriction.
Ultrasound Q
PUBLISHED: 07-23-2013
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Fetal growth disturbances include fetuses at risk for intrauterine growth restriction. These fetuses may have an estimated fetal weight at less than the 10% or demonstrate a plateau of fetal growth with an estimated fetal growth greater than the 10%. Uteroplacental insufficiency may play a major role in the etiology of intrauterine growth restriction. Fetuses at risk for intrauterine fetal growth restriction are susceptible to the potential hostility of the intrauterine environment leading to fetal hypoxia and fetal acidosis. Fetal well-being can be assessed using biophysical profile, Doppler velocimetry, fetal heart rate monitoring, and fetal movement counting.Fetal growth disturbances include fetuses at risk for intrauterine growth restriction. These fetuses may have an estimated fetal weight at less than the 10% or demonstrate a plateau of fetal growth with an estimated fetal growth greater than the 10%. Uteroplacental insufficiency may play a major role in the etiology of intrauterine growth restriction. Fetuses at risk for intrauterine fetal growth restriction are susceptible to the potential hostility of the intrauterine environment leading to fetal hypoxia and fetal acidosis. Fetal well-being can be assessed using biophysical profile, Doppler velocimetry, fetal heart rate monitoring, and fetal movement counting.The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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ACR appropriateness criteria staging and follow-up of ovarian cancer.
J Am Coll Radiol
PUBLISHED: 07-19-2013
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Imaging is used to detect and characterize adnexal masses and to stage ovarian cancer both before and after initial treatment, although the role for imaging in screening for ovarian cancer has not been established. CT and MRI have been used to determine the resectability of tumors, the candidacy of patients for effective cytoreductive surgery, the need for postoperative chemotherapy if debulking is suboptimal, and the need for referral to a gynecologic oncologist. Radiographic studies such as contrast enema and urography have been replaced by CT and other cross-sectional imaging for staging ovarian cancer. Contrast-enhanced CT is the procedure of choice for preoperative staging of ovarian cancer. MRI without and with contrast may be useful after equivocal CT, but is usually not the best initial procedure for ovarian cancer staging. Fluorine-18-2-fluoro-2-deoxy-D-glucose-PET/CT may not be needed preoperatively, but its use is appropriate for detecting and defining post-treatment recurrence. Ultrasound is useful for evaluating adnexal disease, but has limited utility for staging ovarian cancer. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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Undervaccination of perinatally HIV-infected and HIV-exposed uninfected children in Latin America and the Caribbean.
Pediatr. Infect. Dis. J.
PUBLISHED: 07-18-2013
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Perinatally HIV-infected (PHIV) children may be at risk of undervaccination. Vaccination coverage rates among PHIV and HIV-exposed uninfected (HEU) children in Latin America and the Caribbean were compared.
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Infection due to Mycobacterium avium subsp. avium in a free-ranging common seal (Phoca vitulina) in Scotland.
J. Wildl. Dis.
PUBLISHED: 06-20-2013
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We describe the first reported case of mycobacterial infection in a free-ranging pinniped in the Northern Hemisphere. Acid-fast bacteria were demonstrated histologically in the liver of an adult female common seal (Phoca vitulina), and Mycobacterium avium subsp. avium was cultured from the liver.
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ACR appropriateness Criteria® first trimester bleeding.
Ultrasound Q
PUBLISHED: 05-14-2013
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Vaginal bleeding is not uncommon in the first trimester of pregnancy. Ultrasound is the foremost modality for evaluating normal development of the gestational sac and embryo and for discriminating the causes of bleeding. While correlation with quantitative ?HCG and clinical presentation is essential, sonographic criteria permit diagnosis of failed pregnancies, ectopic pregnancy, gestational trophoblastic disease and spontaneous abortion. The American College of Radiology Appropriateness Criteria guidelines have been updated to incorporate recent data. A failed pregnancy may be diagnosed when there is absence of cardiac activity in an embryo exceeding 7 mm in crown rump length or absence of an embryo when the mean sac diameter exceeds 25 mm. In a stable patient with no intrauterine pregnancy and normal adnexae, close monitoring is advised. The diagnosis of ectopic pregnancy should be based on positive findings rather than on the absence of an intrauterine sac above a threshold level of ?HCG. Following abortion, ultrasound can discriminate retained products of conception from clot and arteriovenous fistulae. The American College of Radiology Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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Metabolic activation of CaMKII by coenzyme A.
Mol. Cell
PUBLISHED: 04-24-2013
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Active metabolism regulates oocyte cell death via calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated phosphorylation of caspase-2, but the link between metabolic activity and CaMKII is poorly understood. Here we identify coenzyme A (CoA) as the key metabolic signal that inhibits Xenopus laevis oocyte apoptosis by directly activating CaMKII. We found that CoA directly binds to the CaMKII regulatory domain in the absence of Ca(2+) to activate CaMKII in a calmodulin-dependent manner. Furthermore, we show that CoA inhibits apoptosis not only in X. laevis oocytes but also in Murine oocytes. These findings uncover a direct mechanism of CaMKII regulation by metabolism and further highlight the importance of metabolism in preserving oocyte viability.
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Insulin directly regulates steroidogenesis via induction of the orphan nuclear receptor DAX-1 in testicular Leydig cells.
J. Biol. Chem.
PUBLISHED: 04-15-2013
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Testosterone level is low in insulin-resistant type 2 diabetes. Whether this is due to negative effects of high level of insulin on the testes caused by insulin resistance has not been studied in detail. In this study, we found that insulin directly binds to insulin receptors in Leydig cell membranes and activates phospho-insulin receptor-? (phospho-IR-?), phospho-IRS1, and phospho-AKT, leading to up-regulation of DAX-1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) gene expression in the MA-10 mouse Leydig cell line. Insulin also inhibits cAMP-induced and liver receptor homolog-1 (LRH-1)-induced steroidogenic enzyme gene expression and steroidogenesis. In contrast, knockdown of DAX-1 reversed insulin-mediated inhibition of steroidogenesis. Whether insulin directly represses steroidogenesis through regulation of steroidogenic enzyme gene expression was assessed in insulin-injected mouse models and high fat diet-induced obesity. In insulin-injected mouse models, insulin receptor signal pathway was activated and subsequently inhibited steroidogenesis via induction of DAX-1 without significant change of luteinizing hormone or FSH levels. Likewise, the levels of steroidogenic enzyme gene expression and steroidogenesis were low, but interestingly, the level of DAX-1 was high in the testes of high fat diet-fed mice. These results represent a novel regulatory mechanism of steroidogenesis in Leydig cells. Insulin-mediated induction of DAX-1 in Leydig cells of testis may be a key regulatory step of serum sex hormone level in insulin-resistant states.
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Identifying the mesenchymal molecular subtype of glioblastoma using quantitative volumetric analysis of anatomic magnetic resonance images.
Neuro-oncology
PUBLISHED: 02-26-2013
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Subtypes of glioblastoma multiforme (GBM) based on genetic and molecular alterations are thought to cause alterations in anatomic MRI owing to downstream biological changes, such as edema production, blood-brain barrier breakdown, and necrosis. The purpose of the current study was to identify a potential relationship between imaging features and the mesenchymal (MES) GBM subtype, which has the worst patient prognosis.
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Diffusion tensor imaging detects microstructural reorganization in the brain associated with chronic irritable bowel syndrome.
Pain
PUBLISHED: 02-22-2013
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Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by recurring abdominal pain associated with alterations in bowel habits. We hypothesized that patients with chronic visceral pain associated with IBS may have microstructural differences in the brain compared with healthy control subjects (HCs), indicative of long-term neural reorganization of chronic pain pathways and regions associated with sensory integration. In the current study we performed population-based voxel-wise diffusion tensor imaging (DTI) comparisons and probabilistic tractography in a large sample of phenotyped patients with IBS (n=33) and in HCs (n=93). Patients had lower fractional anisotropy (FA) in thalamic regions, the basal ganglia (BG) and sensory/motor association/integration regions as well as higher FA in frontal lobe regions and the corpus callosum. In addition, patients had reduced mean diffusivity (MD) within the globus pallidus (GP) and higher MD in the thalamus, internal capsule, and coronal radiata projecting to sensory/motor regions, suggestive of differential changes in axon/dendritic density in these regions. Sex differences in FA and MD were also observed in the patients but not in HCs. Probabilistic tractography in patients confirmed a higher degree of connectivity between the thalamus and prefrontal cortex, as well as between the medial dorsal thalamic nuclei and anterior cingulate cortex, and a lower degree of connectivity between the GP and thalamus. Together, these results support the hypothesis that patients with chronically recurring visceral pain from IBS have long-term microstructural changes within the brain, particularly in regions associated with integration of sensory information and corticothalamic modulation.
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ANG II causes insulin resistance and induces cardiac metabolic switch and inefficiency: a critical role of PDK4.
Am. J. Physiol. Heart Circ. Physiol.
PUBLISHED: 02-08-2013
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The renin-angiotensin system (RAS) may alter cardiac energy metabolism in heart failure. Angiotensin II (ANG II), the main effector of the RAS in heart failure, has emerged as an important regulator of cardiac hypertrophy and energy metabolism. We studied the metabolic perturbations and insulin response in an ANG II-induced hypertrophy model. Ex vivo heart perfusion showed that hearts from ANG II-treated mice had a lower response to insulin with significantly reduced rates of glucose oxidation in association with increased pyruvate dehydrogenase kinase 4 (PDK4) levels. Palmitate oxidation rates were significantly reduced in response to insulin in vehicle-treated hearts but remained unaltered in ANG II-treated hearts. Furthermore, phosphorylation of Akt was also less response to insulin in ANG II-treated wild-type (WT) mice, suggestive of insulin resistance. We evaluated the role of PDK4 in the ANG II-induced pathology and showed that deletion of PDK4 prevented ANG II-induced diastolic dysfunction and normalized glucose oxidation to basal levels. ANG II-induced reduction in the levels of the deacetylase, SIRT3, was associated with increased acetylation of pyruvate dehydrogenase (PDH) and a reduced PDH activity. In conclusion, our findings show that a combination of insulin resistance and decrease in PDH activity are involved in ANG II-induced reduction in glucose oxidation, resulting in cardiac inefficiency. ANG II reduces PDH activity via acetylation of PDH complex, as well as increased phosphorylation in response to increased PDK4 levels.
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Insulin resistance and glucose and lipid concentrations in a cohort of perinatally HIV-infected Latin American children.
Pediatr. Infect. Dis. J.
PUBLISHED: 01-31-2013
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We measured glucose, insulin and lipids in 249 perinatally HIV-infected Latin American children. Only 1 subject had impaired fasting glucose; 6.8% had insulin resistance. Abnormalities in total, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides were reported for 13%, 13%, 21% and 34%, respectively. Continued follow-up of this population is necessary to characterize the evolution and clinical consequences of these findings.
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ACR Appropriateness Criteria® clinically suspected adnexal mass.
Ultrasound Q
PUBLISHED: 01-30-2013
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Adnexal masses are a common problem clinically and imaging-wise, and transvaginal US (TVUS) is the first-line imaging modality for assessing them in the vast majority of patients. The findings of US, however, should be correlated with the history and laboratory tests, as well as any patient symptoms. Simple cysts are uniformly benign, and most warrant no further interrogation or treatment. Complex cysts carry more significant implications, and usually engender serial ultrasound(s), with a minority of cases warranting a pelvic MRI.Morphological analysis of adnexal masses with gray-scale US can help narrow the differential diagnosis. Spectral Doppler analysis has not proven useful in most well-performed studies. However, the use of color Doppler sonography adds significant contributions to differentiating between benign and malignant masses and is recommended in all cases of complex masses. Malignant masses generally demonstrate neovascularity, with abnormal branching vessel morphology. Optimal sonographic evaluation is achieved by using a combination of gray-scale morphologic assessment and color or power Doppler imaging to detect flow within any solid areas.The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
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Radiology on the Africa Mercy, the largest private floating hospital ship in the world.
AJR Am J Roentgenol
PUBLISHED: 01-25-2013
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The Africa Mercy, a rehabilitated Danish ferry, is the largest private hospital ship in the world, devoted to providing medical and surgical care to the residents of West Africa, one of the poorest regions on the globe.
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Pre- and post-contrast three-dimensional double inversion-recovery MRI in human glioblastoma.
J. Neurooncol.
PUBLISHED: 01-15-2013
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Fluid attenuated inversion recovery (FLAIR) MRI sequences have become an indispensible tool for defining the malignant boundary in patients with brain tumors by nulling the signal contribution from cerebrospinal fluid allowing both regions of edema and regions of non-enhancing, infiltrating tumor to become hyperintense on resulting images. In the current study we examined the utility of a three-dimensional double inversion recovery (DIR) sequence that additionally nulls the MR signal associated with white matter, implemented either pre-contrast or post-contrast, in order to determine whether this sequence allows for better differentiation between tumor and normal brain tissue. T1- and T2-weighted, FLAIR, dynamic susceptibility contrast (DSC)-MRI estimates of cerebral blood volume (rCBV), contrast-enhanced T1-weighted images (T1+C), and DIR data (pre- or post-contrast) were acquired in 22 patients with glioblastoma. Contrast-to-noise (CNR) and tumor volumes were compared between DIR and FLAIR sequences. Line profiles across regions of tumor were generated to evaluate similarities between image contrasts. Additionally, voxel-wise associations between DIR and other sequences were examined. Results suggested post-contrast DIR images were hyperintense (bright) in regions spatially similar those having FLAIR hyperintensity and hypointense (dark) in regions with contrast-enhancement or elevated rCBV due to the high sensitivity of 3D turbo spin echo sequences to susceptibility differences between different tissues. DIR tumor volumes were statistically smaller than tumor volumes as defined by FLAIR (Paired t test, P = 0.0084), averaging a difference of approximately 14 mL or 24 %. DIR images had approximately 1.5× higher lesion CNR compared with FLAIR images (Paired t test, P = 0.0048). Line profiles across tumor regions and scatter plots of voxel-wise coherence between different contrasts confirmed a positive correlation between DIR and FLAIR signal intensity and a negative correlation between DIR and both post-contrast T1-weighted image signal intensity and rCBV. Additional discrepancies between FLAIR and DIR abnormal regions were also observed, together suggesting DIR may provide additional information beyond that of FLAIR.
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Effect of hand position on EMG activity of the posterior shoulder musculature during a horizontal abduction exercise.
J Strength Cond Res
PUBLISHED: 01-11-2013
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The reverse fly machine is a popular exercise for strengthening the horizontal shoulder abductors including the posterior deltoid. There seems to be little consensus as to which hand position most effectively targets the posterior deltoid despite this option on most machines. This study investigated the impact of varying ones hand position, and consequently altering shoulder joint rotation, on muscle activity in various glenohumeral muscles during exercise on the reverse fly machine. Nineteen resistance-trained men (mean age = 23.2 ± 4.3 years; height = 176.9 ± 7.1 centimeters; body mass = 81.3 ± 10.5 kilograms; body mass index = 25.9 ± 2.6) were recruited from a university population to participate in the study. In a repeated measures design, subjects grasped the hand bars on the machine with either a pronated (PRO) or neutral (NEU) grip and performed dynamic horizontal abduction repetitions to muscular failure using a load equating to approximately 75% body weight. The order of performance of the hand positions was counterbalanced between participants so that approximately half of the subjects performed PRO first and the other half performed NEU first. Surface electromyography was used to record both mean and peak muscle activity of the posterior deltoid, middle deltoid, and infraspinatus. Results showed that mean electromyography activity for the posterior deltoid was significantly greater in NEU compared with PRO (p = 0.046; 95% CI = 0.1-7.4% maximal voluntary isometric contraction). Similarly, mean electromyography activity of the infraspinatus also was significantly greater in NEU compared with PRO (p = 0.002; 95% CI = 3.7-13.6% maximal voluntary isometric contraction). The results of this study show that performing exercise on the reverse fly machine with a neutral hand position significantly increases activity of the posterior deltoid and infraspinatus muscles compared with a PRO hand position.
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Scoparone Exerts Anti-Tumor Activity against DU145 Prostate Cancer Cells via Inhibition of STAT3 Activity.
PLoS ONE
PUBLISHED: 01-01-2013
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Scoparone, a natural compound isolated from Artemisia capillaris, has been used in Chinese herbal medicine to treat neonatal jaundice. Signal transducer and activator of transcription 3 (STAT3) contributes to the growth and survival of many human tumors. This study was undertaken to investigate the anti-tumor activity of scoparone against DU145 prostate cancer cells and to determine whether its effects are mediated by inhibition of STAT3 activity. Scoparone inhibited proliferation of DU145 cells via cell cycle arrest in G1 phase. Transient transfection assays showed that scoparone repressed both constitutive and IL-6-induced transcriptional activity of STAT3. Western blot and quantitative real-time PCR analyses demonstrated that scoparone suppressed the transcription of STAT3 target genes such as cyclin D1, c-Myc, survivin, Bcl-2, and Socs3. Consistent with this, scoparone decreased phosphorylation and nuclear accumulation of STAT3, but did not reduce phosphorylation of janus kinase 2 (JAK2) or Src, the major upstream kinases responsible for STAT3 activation. Moreover, transcriptional activity of a constitutively active mutant of STAT3 (STAT3C) was inhibited by scoparone, but not by AG490, a JAK2 inhibitor. Furthermore, scoparone treatment suppressed anchorage-independent growth in soft agar and tumor growth of DU145 xenografts in nude mice, concomitant with a reduction in STAT3 phosphorylation. Computational modeling suggested that scoparone might bind the SH2 domain of STAT3. Our findings suggest that scoparone elicits an anti-tumor effect against DU145 prostate cancer cells in part through inhibition of STAT3 activity.
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TLTF in Cerebrospinal Fluid for Detection and Staging of T. b. gambiense Infection.
PLoS ONE
PUBLISHED: 01-01-2013
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Trypanosome-derived lymphocyte triggering factor (TLTF) is a molecule released by African trypanosomes that interacts with the host immune system, resulting in increased levels of IFN-? production.
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Genetic inactivation of pyruvate dehydrogenase kinases improves hepatic insulin resistance induced diabetes.
PLoS ONE
PUBLISHED: 01-01-2013
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Pyruvate dehydrogenase kinases (PDK1-4) play a critical role in the inhibition of the mitochondrial pyruvate dehydrogenase complex especially when blood glucose levels are low and pyruvate can be conserved for gluconeogenesis. Under diabetic conditions, the Pdk genes, particularly Pdk4, are often induced, and the elevation of the Pdk4 gene expression has been implicated in the increased gluconeogenesis in the liver and the decreased glucose utilization in the peripheral tissues. However, there is no direct evidence yet to show to what extent that the dysregulation of hepatic Pdk genes attributes to hyperglycemia and insulin resistance in vivo. To address this question, we crossed Pdk2 or Pdk4 null mice with a diabetic model that is deficient in hepatic insulin receptor substrates 1 and 2 (Irs1/2). Metabolic analyses reveal that deletion of the Pdk4 gene had better improvement in hyperglycemia and glucose tolerance than knockout of the Pdk2 gene whereas the Pdk2 gene deletion showed better insulin tolerance as compared to the Pdk4 gene inactivation on the Irs1/2 knockout genetic background. To examine the specific hepatic effects of Pdks on diabetes, we also knocked down the Pdk2 or Pdk4 gene using specific shRNAs. The data also indicate that the Pdk4 gene knockdown led to better glucose tolerance than the Pdk2 gene knockdown. In conclusion, our data suggest that hepatic Pdk4 may be critically involved in the pathogenesis of diabetes.
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Intense inflammation and nerve damage in early multiple sclerosis subsides at older age: a reflection by cerebrospinal fluid biomarkers.
PLoS ONE
PUBLISHED: 01-01-2013
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Inflammatory mediators have crucial roles in leukocyte recruitment and subsequent central nervous system (CNS) neuroinflammation. The extent of neuronal injury and axonal loss are associated with the degree of CNS inflammation and determine physical disability in multiple sclerosis (MS). The aim of this study was to explore possible associations between a panel of selected cerebrospinal fluid biomarkers and robust clinical and demographic parameters in a large cohort of patients with MS and controls (n?=?1066) using data-driven multivariate analysis. Levels of matrix metalloproteinase 9 (MMP9), chemokine (C-X-C motif) ligand 13 (CXCL13), osteopontin (OPN) and neurofilament-light chain (NFL) were measured by ELISA in 548 subjects comprising different MS subtypes (relapsing-remitting, secondary progressive and primary progressive), clinically isolated syndrome and persons with other neurological diseases with or without signs of inflammation/infection. Principal component analyses and orthogonal partial least squares methods were used for unsupervised and supervised interrogation of the data. Models were validated using data from a further 518 subjects in which one or more of the four selected markers were measured. There was a significant association between increased patient age and lower levels of CXCL13, MMP9 and NFL. CXCL13 levels correlated well with MMP9 in the younger age groups, but less so in older patients, and after approximately 54 years of age the levels of CXCL13 and MMP9 were consistently low. CXCL13 and MMP9 levels also correlated well with both NFL and OPN in younger patients. We demonstrate a strong effect of age on both inflammatory and neurodegenerative biomarkers in a large cohort of MS patients. The findings support an early use of adequate immunomodulatory disease modifying drugs, especially in younger patients, and may provide a biological explanation for the relative inefficacy of such treatments in older patients at later disease stages.
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Role of pyruvate dehydrogenase kinase 4 in regulating PDH activation during acute muscle contraction.
Appl Physiol Nutr Metab
PUBLISHED: 12-23-2011
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The oxidation of carbohydrates in mammals is regulated by the pyruvate dehydrogenase (PDH) complex, which is covalently regulated by four PDH kinases (PDK1-4) and two PDH phosphatases (PDP1-2) unique to the PDH complex. To investigate the role that PDK4 plays in regulating PDH activation (PDHa) during muscle contraction, mouse extensor digitorum muscle was removed from wild type (WT) and PDK4-knockout (PDK4-KO) mice after a 24 h fast and stimulated for 3 min either at 10 Hz (low-intensity contraction), 40 Hz (moderate-intensity contraction), or allowed to rest. Force was recorded and muscle PDHa activity and metabolite concentrations were measured. PDHa activity was ?2.5-fold higher at rest in PDK4-KO mice than WT mice (P = 0.009) and ?2-fold higher in PDK4-KO mice at both 10 Hz (P < 0.001) and 40 Hz (P < 0.001). Force relative to muscle weight was similar at 10 Hz, but was 5.8 ± 0.7 mN·g(-1) in PDK4-KO mice and 3.5 ± 0.7 mN·g(-1) in WT mice at 40 Hz (P < 0.001), with a similar rate of fatigue in both genotypes. From these results it was concluded that PDK4 plays a role in reducing PDHa activity during low to moderate-intensity muscle stimulation, and that absence of PDK4 and the subsequent changes in carbohydrate utilization may alter force production.
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Evaluation of two methods in controlling dental treatment water contamination.
J Contemp Dent Pract
PUBLISHED: 12-22-2011
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Dental unit water systems are contaminated with biofilms that amplify bacterial counts in dental treatment water in excess of a million colony forming units per milliliter (cfu/ml). The Centers for Disease Control and Prevention and the American Dental Association have agreed that the maximum allowable contamination of dental treatment water not exceed 500 cfu/ml. This study was conducted to evaluate two protocols in controlling contamination of dental unit water systems and dental treatment water. Both methods used an antimicrobial self-dissolving chlorine dioxide (ClO?) tablet at a high concentration (50 ppm) to shock the dental unit water system biofilms initially followed by periodic exposure. To treat dental treatment source water for patient care, 3 parts per million (ppm) ClO? in municipal/tap water was compared to use of a citrus botanical extract dissolved in municipal water. Heterotrophic microbial counts of effluent water and laser scanning confocal microscopy were performed to evaluate effects of the two treatments. Results from this study indicated that both treatments were effective in controlling biofilm contamination and reducing heterotrophic plate counts <500 cfu/ml. A comprehensive study addressing compatibility of 50 ppm ClO? on the metals and nonmetal components of the dental water system and effects of low-grade chemicals used on composite bonding to dentin and enamel is warranted before translation from efficacy studies to common clinical use. Clinical significance: This study provides evidence-based information of using two methods of controlling dental treatment water contamination. The study was conducted in a clinical practice setting in an active dental clinic and the results are meaningful to a clinician who is interested in providing safe dental treatment water for patient care. Keywords: Dental waterline biofilms, Dental treatment water contamination control, Chlorine dioxide, Emulsifiers, Heterotrophic plate counts, Laser scanning confocal microscopy. How to cite this article: Bansal R, Puttaiah R, Harris R, Reddy A. Evaluation of Two Methods in Controlling Dental Treatment Water Contamination. J Contemp Dent Pract 2011;12(2):73-83. Source of support: Nil Conflict of interest: None declared.
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Intra-individual assessment of speech and music perception in cochlear implant users with contralateral Cochlear™ and MED-EL™ systems.
Acta Otolaryngol.
PUBLISHED: 11-15-2011
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Whilst objective testing on music perception showed no individual differences between cochlear implant (CI) devices, subjective music perception was found to be superior with the MED-EL device in the majority of cases evaluated.
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Synergy from silence in a combinatorial neural code.
J. Neurosci.
PUBLISHED: 11-04-2011
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The manner in which groups of neurons represent events in the external world is a central question in neuroscience. Estimation of the information encoded by small groups of neurons has shown that in many neural systems, cells carry mildly redundant information. These measures average over all the activity patterns of a neural population. Here, we analyze the population code of the salamander and guinea pig retinas by quantifying the information conveyed by specific multicell activity patterns. Synchronous spikes, even though they are relatively rare and highly informative, convey less information than the sum of either spike alone, making them redundant coding symbols. Instead, patterns of spiking in one cell and silence in others, which are relatively common and often overlooked as special coding symbols, were found to be mostly synergistic. Our results reflect that the mild average redundancy between ganglion cells that was previously reported is actually the result of redundant and synergistic multicell patterns, whose contributions partially cancel each other when taking the average over all patterns. We further show that similar coding properties emerge in a generic model of neural responses, suggesting that this form of combinatorial coding, in which specific compound patterns carry synergistic or redundant information, may exist in other neural circuits.
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Molecular motion and ion diffusion in choline chloride based deep eutectic solvents studied by 1H pulsed field gradient NMR spectroscopy.
Phys Chem Chem Phys
PUBLISHED: 10-28-2011
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Deep Eutectic Solvents (DESs) are a novel class of solvents with potential industrial applications in separation processes, chemical reactions, metal recovery and metal finishing processes such as electrodeposition and electropolishing. Macroscopic physical properties such as viscosity, conductivity, eutectic composition and surface tension are already available for several DESs, but the microscopic transport properties for this class of compounds are not well understood and the literature lacks experimental data that could give a better insight into the understanding of such properties. This paper presents the first pulsed field gradient nuclear magnetic resonance (PFG-NMR) study of DESs. Several choline chloride based DESs were chosen as experimental samples, each of them with a different associated hydrogen bond donor. The molecular equilibrium self-diffusion coefficient of both the choline cation and hydrogen bond donor was probed using a standard stimulated echo PFG-NMR pulse sequence. It is shown that the increasing temperature leads to a weaker interaction between the choline cation and the correspondent hydrogen bond donor. The self-diffusion coefficients of the samples obey an Arrhenius law temperature-dependence, with values of self-diffusivity in the range of [10(-10)-10(-13) m(2) s(-1)]. In addition, the results also highlight that the molecular structure of the hydrogen bond donor can greatly affect the mobility of the whole system. While for ethaline, glyceline and reline the choline cation diffuses slower than the associated hydrogen bond donor, reflecting the trend of molecular size and molecular weight, the opposite behaviour is observed for maline, in which the hydrogen bond donor, i.e. malonic acid, diffuses slower than the choline cation, with self-diffusion coefficients values of the order of 10(-13) m(2) s(-1) at room temperature, which are remarkably low values for a liquid. This is believed to be due to the formation of extensive dimer chains between malonic acid molecules, which restricts the mobility of the whole system at low temperature (<30 °C), with malonic acid and choline chloride having almost identical diffusivity values. Diffusion and viscosity data were combined together to gain insights into the diffusion mechanism, which was found to be the same as for ionic liquids with discrete anions.
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Choline phosphorylation and regulation of transcription of choline kinase ? in hypoxia.
J. Lipid Res.
PUBLISHED: 10-24-2011
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Choline kinase catalyzes the phosphorylation of choline, the first step of phospholipid synthesis. Increased phosphorylation of choline is a hallmark characteristic of the malignant phenotype in a variety of neoplasms. However, in hypoxic cancer cells, choline phosphorylation is decreased. To understand the mechanism behind this altered metabolic state, we examined the expression and regulation of the major choline kinase isoform, choline kinase ? (ChK?), in hypoxic PC-3 human prostate cancer cells. Hypoxia decreased choline phosphorylation, choline kinase activity, and ChK? mRNA and protein levels. Promoter analysis studies revealed a region upstream of the ChK? gene bearing a conserved DNA consensus binding motif, hypoxia response element-7 (HRE7), at position -222 relative to +1 translation start site, for binding the hypoxia dependent master regulator transcription factor, hypoxia-inducible factor 1? (HIF-1?). Electrophoretic mobility shift competition/supershift assay and chromatin immunoprecipitation assay confirmed binding of HIF-1? to HRE7. A putative promoter of ChK? was isolated from PC-3 genomic DNA and cloned into a luciferase-based reporter vector system. In PC-3 cells, hypoxia decreased the expression of luciferase under the control of the ChK? promoter. Mutation of HRE7 abrogated this hypoxia effect, further demonstrating the involvement of HRE7 in hypoxia-sensitive regulation of ChK?. The results strongly suggest that transcriptional control of choline phosphorylation is largely mediated via HIF-1? binding to the newly identified HRE7.
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Polyfluoroalkyl compounds in Texas children from birth through 12 years of age.
Environ. Health Perspect.
PUBLISHED: 08-10-2011
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For > 50 years, polyfluoroalkyl compounds (PFCs) have been used worldwide, mainly as surfactants and emulsifiers, and human exposure to some PFCs is widespread.
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Methamphetamine use and risk for HIV among young men who have sex with men in 8 US cities.
Arch Pediatr Adolesc Med
PUBLISHED: 08-04-2011
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To examine methamphetamine use and its association with sexual behavior among young men who have sex with men.
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Sweet and sour--oxidative and carbonyl stress in neurological disorders.
CNS Neurol Disord Drug Targets
PUBLISHED: 07-30-2011
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The nervous system is a unique network of different cell types and comprises a variety of proteins, lipids, and carbohydrates that have an important interplay with all major organs in the body. Homeostatic regulation of nervous tissue turnover must be carefully controlled, taking into account interactions of the nervous, endocrine, and immune systems. Clinical conditions affecting the nervous system range from mild cognitive perturbations such as headache, to life-threatening acute courses such as meningitis and glioblastoma, and to chronic neurodegenerative diseases such as multiple sclerosis. One unifying feature in normal developmental or homeostatic functions and clinical dysfunctions within the nervous system is redox regulation, with an imbalance in oxidative/carbonyl stress versus antioxidants being characteristic of pathological conditions. In this review we consider the state of current knowledge regarding structural, genetic, proteomic, histopathological, clinical, and therapeutic perspectives of oxidative and carbonyl stress within the nervous system.
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Correlates of HIV testing history among urban youth recruited through venue-based testing in 15 US cities.
Sex Transm Dis
PUBLISHED: 07-16-2011
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Adolescents and young adults comprise disproportionately high percentages of individuals living with human immunodeficiency virus (HIV) and those with undiagnosed HIV. Our objective was to determine factors associated with history of HIV testing and receipt of results among a sample of urban, high-risk, sexually active adolescents in 15 US cities.
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A practical, single-view alternative to Stenvers for plain radiographic unilateral and bilateral post-cochlear implant position check.
Cochlear Implants Int
PUBLISHED: 07-16-2011
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Stenvers is the standard plain radiograph view to check the electrode position after cochlear implantation. However, a reproducible alignment for intra-individual comparison of electrode position using a true Stenvers alignment is not always straightforward to achieve, particularly for inexperienced radiographers, or on non-compliant children. In addition, two ionizing exposures in two different positions are required for bilateral cochlear implants.
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