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Find video protocols related to scientific articles indexed in Pubmed.
Intact pituitary function is decisive for the catabolic response to TNF-? - studies of protein, glucose and fatty acid metabolism in hypopituitary and healthy subjects.
J. Clin. Endocrinol. Metab.
PUBLISHED: 11-07-2014
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Context: TNF-? generates inflammatory responses and insulin resistance, lipolysis and protein breakdown. It is unclear whether these changes depend on intact hypothalamo-pituitary stress hormone responses triggering release of cortisol and growth hormone. Objective: To define differential effects of TNF-? on glucose, protein and lipid metabolism in hypopituitary patients (without intact hypothalamo-pituitary axis) and healthy controls. Design: Randomized, placebo controlled, single-blinded. Setting, participants and intervention: We studied eight hypopituitary patients(HP) and eight matched control subjects(CTR) twice during 4-h basal and 2-h hyperinsulinemic clamp conditions with isotope dilution during infusion of saline or TNF-?(12 ng/kg/h) for 6 h. Main outcome measures: Phenylalanine, urea, palmitate and glucose fluxes and fat biopsies in basal and clamp periods. Results: TNF-? infusion significantly increased cortisol and GH levels in CTR but not in HP. TNF-? increased phenylalanine fluxes in both groups, the increase being significantly greater in CTR, and raised urea flux by 40 % in CTR without any alteration in HP. Endogenous glucose production(EGP) was elevated in CTR compared to HP after TNF-? administration, whereas insulin sensitivity remained similarly unaffected in both groups. TNF-? increased whole body palmitate fluxes and decreased palmitate specific activity in CTR, but not in HP without statistical difference between groups. We did not detect significant effects TNF-? on lipase expression or regulation in fat. Conclusions: TNF-? increased both urea and amino acid fluxes and EGP significantly more in CTR compared to HP, suggesting that increases in endogenous cortisol and GH release are significant components of the metabolic response to TNF-?.
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A novel FBN1 variant in a large Marfan family with high penetrance of aortic dissection or rupture.
Dan Med J
PUBLISHED: 11-06-2014
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Marfan syndrome is an autosomal, dominantly inherited disorder of the connective tissue. We report the clinical data and results of a genetic analysis of a large Danish Marfan family.
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[A fatal overdose of venlafaxine.]
Ugeskr. Laeg.
PUBLISHED: 10-29-2014
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An 18-year-old woman ingested 22 g of venlafaxine with suicidal attempt. At admittance two hours after ingestion she had serotonine syndrome, repeated seizures and hypotension. After eight hours malignant arrythmias culminated in cardiac arrest, which was successfully resuscitated. Progressive liver and cardiac failure lead to fatal outcome after 48 hours. It is discussed whether early lipid infusion should be given in case of ingestion of high doses of venlafaxine, before myoclonia, seizures, hypotension, rhabdomyolysis and liver failure developed, since these can only be treated symptomatically.
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Improved Adhesion Between PMMA and Stainless Steel Modified with PMMA Brushes.
ACS Appl Mater Interfaces
PUBLISHED: 10-29-2014
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In this work, various lengths and densities of poly(methyl methacrylate) (PMMA) brushes were synthesized on stainless steel (SS) surfaces via surface initiated atom transfer radical polymerization. Subsequently, the joints between the bulk PMMA and the PMMA brushed stainless steel were obtained by injection molding, and for these the degree of adhesion was assessed by tensile testing. Several conditions are required to facilitate the mixing between the brushes and the bulk polymer and to reduce the residual stress at the interface: preheating of the SS samples before the injection molding; a long packing time; and a mold temperature above the glass transition temperature (Tg) of PMMA during the injection molding. This treatment leads to a cohesive failure in the bulk PMMA. It was observed that the stress concentrated at the rim, due to contraction of bulk PMMA during cooling, results in a weak adhesion at the rim of the joint. A combination of high density and long brush length of PMMA film provides better adhesion. The large number of PMMA brush chains apparently promotes good penetration into the bulk PMMA chains and ultimately results in high adhesion strength.
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Resveratrol Increases Bone Mineral Density and Bone Alkaline Phosphatase in Obese Men: A Randomized Placebo-Controlled Trial.
J. Clin. Endocrinol. Metab.
PUBLISHED: 10-17-2014
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Context: Metabolic syndrome (MetS) is associated with low-grade inflammation, which may harmfully affect bone. Resveratrol (RSV) possesses anti-inflammatory properties, and rodent studies suggest bone protective effects. Objective: This study sought to evaluate effects of RSV treatment on bone in men with MetS. Setting and Design: The study was conducted at Aarhus University Hospital as a randomized, double-blinded, placebo-controlled trial assessing changes in bone turnover markers, bone mineral density (BMD), and geometry. Participants: The study population comprised 74 middle-aged obese men with MetS recruited from the general community, of which 66 completed all visits. Mean age of participants was 49.3 ± 6.3 years and mean body mass index was 33.7 ± 3.6 kg/m(2). Intervention: Oral treatment with 1.000 mg RSV (RSVhigh), 150mg RSV (RSVlow), or placebo daily for 16 weeks. Main Outcome Measure: Prespecified primary endpoint was change in bone alkaline phosphatase (BAP). Results: BAP increased dose dependently with RSV (R = 0.471, P < .001), resulting in a significantly greater increase in BAP in the RSVhigh group compared with placebo at all time-points (week 4, 16.4 ± 4.2%, P < .001; week 8, 16.5 ± 4.1%, P < .001; week 16, 15.2 ± 3.7%, P < .001). Lumbar spine trabecular volumetric bone mineral density (LS vBMDtrab) also increased dose dependently with RSV (R = 0.268, P = .036), with a significant increase of 2.6 ± 1.3% in the RSVhigh group compared with placebo (P = .043). In addition, changes in BAP and LS vBMDtrab were positively correlated (R = 0.281, P = .027). No consistent changes were detected in bone density at the hip. Conclusions: Our data suggest that high-dose RSV supplementation positively affects bone, primarily by stimulating formation or mineralization. Future studies of longer duration comprising populations at risk of osteoporosis are needed to confirm these results.
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Intake of St. John's wort improves the glucose tolerance in healthy subjects that ingest metformin compared to metformin alone.
Br J Clin Pharmacol
PUBLISHED: 09-20-2014
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Our object was to investigate the steady-state pharmacokinetic and pharmacodynamic interaction between the antidepressive herbal medicine St. John's wort (SJW) and the antidiabetic drug metformin.
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GH signaling in skeletal muscle and adipose tissue in healthy human subjects: impact of gender and age.
Eur. J. Endocrinol.
PUBLISHED: 08-27-2014
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The mechanisms underlying the impact of age and gender on the GH-IGF1 axis remain unclear. We tested the hypothesis that age and gender have impacts on GH signaling in human subjects in vivo.
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CYP2C19*17 increases the clopidogrel-mediated platelet inhibition but does not alter the pharmacokinetics of the active metabolite of clopidogrel.
Clin. Exp. Pharmacol. Physiol.
PUBLISHED: 08-12-2014
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The purposes were to determine the impact of CYP2C19*17 on the pharmacokinetics and pharmacodynamics of the active metabolite of clopidogrel and the pharmacokinetics of proguanil. Thus, we conducted an open-label, two-phase cross-over study in 31 healthy male volunteers (11 CYP2C19*1/*1, 11 CYP2C19*1/*17 and 9 CYP2C19*17/*17). In phase A, the pharmacokinetics of the derivatized active metabolite of clopidogrel (CAMD) and the platelet function were determined after administration of a single oral dose of 600 mg clopidogrel (Plavix(®) ). In phase B, the pharmacokinetics of proguanil and its metabolites, cycloguanil and 4-chlorphenylbiguanide, were determined in 29 of the 31 subjects after a single oral dose of 200 mg proguanil given as the combination drug Malarone(®) . Statistically significant correlations between the area under the time-concentration curve (AUC0-? ) of CAMD on the one hand and both the absolute ADP-induced P2Y12 -activated platelet aggregation (PRU) (r=-0.60, p=0.0007) and the percent inhibition of aggregation (r=0.59, p=0.0009) on the other hand were found. Besides, the CYP2C19*17/*17 and CYP2C19*1/*17 genotype groups had statistically significantly higher percent inhibition of platelet aggregation compared to the group of CYP2C19*1/*1 subjects (geometric mean of 84%, 73% and 63%, respectively, p=0.014). Neither the PRU, the exposure to CAMD nor the pharmacokinetic parameters of proguanil, cycloguanil and 4-chlorphenylbiguanide showed any statistically significant differences between the genotype groups. In conclusion, carriers of CYP2C19*17 display higher percent inhibition of platelet aggregation but do not have significantly lower absolute P2Y12 -activated platelet aggregation or higher exposure of the active metabolite after a single oral administration of 600 mg clopidogrel. This article is protected by copyright. All rights reserved.
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Regulation of CD163 mRNA and soluble CD163 protein in human adipose tissue in vitro.
J. Mol. Endocrinol.
PUBLISHED: 07-29-2014
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CD163-positive macrophages are highly expressed in the human adipose tissue (AT) particularly from obese individuals. However, little is known about the regulation of CD163 mRNA and the protein level of sCD163 in human AT. We aimed to examine the regulation of CD163 and sCD163 in AT. Human s.c. AT samples (n=5) were stimulated with dexamethasone (DEX; 200? nmol/l), lipopolysaccharide (LPS; 100 ?ng/ml), or DEX+LPS for various time periods up to 24? h. Gene expressions of CD163, ADAM17, IL10, and TNFA (TNF) were measured by RT-PCR. Protein levels of sCD163, IL10, and TNF? (TNF) were measured by ELISA. Furthermore, AT was separated into stromal and adipocyte fraction. We found that CD163 mRNA was strongly expressed in the stromal vascular fraction but hardly detectable in the isolated adipocytes. Incubating whole AT with DEX significantly up-regulated CD163 (P<0.001), whereas incubation with LPS had no effects on CD163 (P>0.05). By contrast, the protein level of sCD163 was not affected by DEX (P>0.05), but LPS significantly increased the level of sCD163 and TNF? (P<0.05). This might be due to the concomitant LPS stimulation of ADAM17, which is known to mediate shedding of the extracellular domains of sCD163 and TNF?. Finally, DEX significantly reduced the LPS-induced TNF? release to the incubation medium but had no effects on sCD163. We conclude that the expression of CD163 and the release of sCD163 are differentially regulated in human AT. Moreover, similar to studies on differentiated blood monocytes, TNF? and sCD163 are concomitantly released in human AT by LPS, which also up-regulate ADAM17.
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Growth hormone signaling in muscle and adipose tissue of obese human subjects: associations with measures of body composition and interaction with resveratrol treatment.
J. Clin. Endocrinol. Metab.
PUBLISHED: 07-23-2014
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Context: Growth hormone (GH) secretion is reduced in obesity despite normal serum insulin-like growth factor I (IGF-I) levels but the association between obesity and GH signaling is unknown. Furthermore, SIRT1, a NAD-dependent protein deacetylase, reduces hepatic IGF-I production in mice via blunting of GH-induced STAT5 signaling. Objective: To study GH signaling in muscle and fat in obese subjects and interaction with concomitant administration of the putative SIRT1 activator resveratrol, and to assess the effects of inhibiting or knocking down SIRT1 on GH regulated genes in vitro. Design and participants: 24 obese males were examined in a randomized, double blinded, parallel-group study with resveratrol or placebo treatment for 5 weeks followed by a GH bolus. Muscle and fat biopsies were collected before and after GH. Body composition was assessed by DEXA and MRI. Main Outcome Measure: 1) Effect of body composition and age on GH-stimulated STAT5b phosphorylation and IGF-I, SOCS2, and CISH mRNA in muscle and fat. 2) Impact of resveratrol treatment on GH activity. 3) Impact of inhibiting or knocking down SIRT1 on effects of GH in vitro. Results: Significant GH-induced STAT5b phosphorylation in muscle and fat in obese subjects was recorded together with increased CISH and SOCS2 mRNA. GH-induced STAT5b phosphorylation in muscle correlated positively with age [r=0.53, p<0.01], but not with body composition. Resveratrol administration had no impact on body composition, serum IGF-I, or GH signaling in vivo, and SIRT1 knock down or inhibition did not affect GH signaling in vitro. Conclusion: 1) GH induced STAT5b phosphorylation is detectable in muscle and fat in adult males with simple obesity, but is not determined by body composition. 2) Resveratrol supplementation does not impact circulating IGF-I levels or GH signaling in human muscle and fat. 3) Our data speak against a major impact of SIRT1on GH action in human subjects.
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Intrahepatic fat content correlates with soluble CD163 in relation to weight loss induced by Roux-en-Y gastric bypass.
Obesity (Silver Spring)
PUBLISHED: 07-13-2014
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Soluble CD163 (sCD163) is a new marker of obesity-related metabolic complications. sCD163 and CD163 mRNA were investigated in relation to the fat distribution at baseline and 12 months after Roux-en-Y gastric bypass (RYGB).
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Kinetics and utilization of lipid sources during acute exercise and acipimox.
Am. J. Physiol. Endocrinol. Metab.
PUBLISHED: 06-03-2014
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Overweight is associated with abnormalities of lipid metabolism, many of which are reversed by exercise. We investigated the impact of experimental antilipolysis and acute exercise on lipid kinetics and oxidation from VLDL-TG, plasma FFA, and "residual lipids" in overweight men (n = 8) using VLDL-TG and palmitate tracers in combination with muscle biopsies in a randomized, placebo-controlled design. Participants received placebo or acipimox on each study day (4 h of rest, 90 min of exercise at 50% V(O(2 max))). Exercise suppressed VLDL-TG secretion significantly during placebo but not acipimox (placebo-rest: 64.2 ± 9.4; placebo-exercise: 48.3 ± 8.0; acipimox-rest: 55.2 ± 13.4; acipimox-exercise: 52.0 ± 10.9). Resting oxidation of VLDL-TG FA and FFA was significantly reduced during acipimox compared with placebo, whereas "residual lipid oxidation" increased significantly [VLDL-TG oxidation (placebo: 18 ± 3 kcal/h; acipimox: 11 ± 2 kcal/h), FFA oxidation (placebo: 14 ± 2 kcal/h; acipimox: 4 ± 0.5 kcal/h), and residual lipid oxidation (placebo: 3 ± 5 kcal/h; acipimox: 14 ± 5 kcal/h)]. Additionally, during exercise on both placebo and acipimox, oxidation of VLDL-TG and FFA increased, but the relative contribution to total lipid oxidation diminished, except for FFA, which remained unchanged during acipimox. Residual lipid oxidation increased significantly during exercise in both absolute and relative terms. Changes in selected cellular enzymes and proteins provided no explanations for kinetic changes. In conclusion, suppressed FFA availability blunts the effect of exercise on VLDL-TG secretion and modifies the contribution of lipid sources for oxidation.
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Controlled electrochemical carboxylation of graphene to create a versatile chemical platform for further functionalization.
Langmuir
PUBLISHED: 05-23-2014
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An electrochemical approach is introduced for the versatile carboxylation of multi-layered graphene in 0.1 M Bu4NBF4/MeCN. First, the graphene substrate (i.e., graphene chemically vapor-deposited on Ni) is negatively charged at -1.9 V versus Ag/AgI in a degassed solution to allow for intercalation of Bu4N(+) and, thereby, separation of the individual graphene sheets. In the next step, the strongly activated and nucleophilic graphene is allowed to react with added carbon dioxide in an addition reaction, introducing carboxylate groups stabilized by Bu4N(+) already present. This procedure may be carried out repetitively to further enhance the carboxylation degree under controlled conditions. Encouragingly, the same degree of control is even attainable, if the intercalation and carboxylation is carried out simultaneously in a one-step procedure, consisting of simply electrolyzing in a CO2-saturated solution at the graphene electrode for a given time. The same functionalization degree is obtained for all multi-layered regions, independent of the number of graphene sheets, which is due to the fact that the entire graphene structure is opened in response to the intercalation of Bu4N(+). Hence, this electrochemical method offers a versatile procedure to make all graphene sheets in a multi-layered but expanded structure accessible for functionalization. On a more general level, this approach will provide a versatile way of forming new hybrid materials based on intimate bond coupling to graphene via carboxylate groups.
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Superhydrophilic polyelectrolyte brush layers with imparted anti-icing properties: effect of counter ions.
ACS Appl Mater Interfaces
PUBLISHED: 04-24-2014
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This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed by polymerization via the SI-ATRP route. The cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride] and the anionic [poly(3-sulfopropyl methacrylate), poly(sodium methacrylate)] polyelectrolyte brushes were further exchanged with H+, Li+, Na+, K+, Ag+, Ca2+, La3+, C16N+, F-, Cl-, BF4-, SO4(2-), and C12SO3- ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li+ ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag+ ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass. In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 °C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL) that is enhanced in the presence of highly hydrated ions at the interface. It is suggested that the ability of ions to coordinate water is directly related to the efficiency of a given anti-icing coating based on the polyelectrolyte brush concept.
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High- versus low-quality graphene: a mechanistic investigation of electrografted diazonium-based films for growth of polymer brushes.
Small
PUBLISHED: 04-19-2014
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Electrografting using aryldiazonium salts provides a fast and efficient technique to functionalize commercially available 3-5 layered graphene (vapour-deposited) on nickel. In this study, Raman spectroscopy is used to quantify the grafting efficiency of cyclic voltammetry which is one of the most versatile, yet simple, electrochemical techniques available. To a large extent the number of defects/substituents introduced to the basal plane of high-quality graphene by this procedure can be controlled through the sweeping conditions employed. After extended electrografting the defect density reaches a saturation level ( ? 10(13) cm(-2)) which is independent of the quality of the graphene expressed through its initial content of defects. However, it is reached within fewer voltammetric cycles for low-quality graphene. Based on these results it is suggested that the grafting occurs (a) directly at defect sites for, in particular, low-quality graphene, (b) directly at the basal plane for, in particular, high-quality graphene, and/or (c) at already grafted molecules to give a mushroom-like film growth for all films. Moreover, it is shown that a tertiary alkyl bromide can be introduced at a given surface density to serve as radical initiator for surface-initiated atom transfer radical polymerization (SI-ATRP). Brushes of poly(methyl methacrylate) are grown from these substrates, and the relationship between polymer thickness and sweeping conditions is studied.
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Exchange interaction of strongly anisotropic tripodal erbium single-ion magnets with metallic surfaces.
ACS Nano
PUBLISHED: 03-24-2014
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We present a comprehensive study of Er(trensal) single-ion magnets deposited in ultrahigh vacuum onto metallic surfaces. X-ray photoelectron spectroscopy reveals that the molecular structure is preserved after sublimation, and that the molecules are physisorbed on Au(111) while they are chemisorbed on a Ni thin film on Cu(100) single-crystalline surfaces. X-ray magnetic circular dichroism (XMCD) measurements performed on Au(111) samples covered with molecular monolayers held at temperatures down to 4 K suggest that the easy axes of the strongly anisotropic molecules are randomly oriented. Furthermore XMCD indicates a weak antiferromagnetic exchange coupling between the single-ion magnets and the ferromagnetic Ni/Cu(100) substrate. For the latter case, spin-Hamiltonian fits to the XMCD M(H) suggest a significant structural distortion of the molecules. Scanning tunneling microscopy reveals that the molecules are mobile on Au(111) at room temperature, whereas they are more strongly attached on Ni/Cu(100). X-ray photoelectron spectroscopy results provide evidence for the chemical bonding between Er(trensal) molecules and the Ni substrate. Density functional theory calculations support these findings and, in addition, reveal the most stable adsorption configuration on Ni/Cu(100) as well as the Ni-Er exchange path. Our study suggests that the magnetic moment of Er(trensal) can be stabilized via suppression of quantum tunneling of magnetization by exchange coupling to the Ni surface atoms. Moreover, it opens up pathways toward optical addressing of surface-deposited single-ion magnets.
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Pooling of porcine fecal samples for quantification of Lawsonia intracellularis by real-time polymerase chain reaction.
J. Vet. Diagn. Invest.
PUBLISHED: 03-12-2014
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Procedures in which biological specimens are mixed and tested as 1 sample (pooling) have been applied for various biological specimens and laboratory examinations. The objective of the current study was to investigate agreement between laboratory testing of fecal pools and theoretical values obtained by averaging test results from individual fecal samples in relation to a quantitative polymerase chain reaction (qPCR) test for Lawsonia intracellularis. Ten diarrheic and 10 normal fecal samples were submitted from each of 43 Danish swine herds (n = 860 fecal samples). Pools (n = 43), each containing 20 individual fecal samples from the same herd, were prepared in the laboratory by pooling 10% fecal phosphate buffered saline solutions. All pools and individual fecal samples were subjected to qPCR testing for L. intracellularis. The theoretical number of L. intracellularis in the pools was calculated as the mean number of bacteria from the 20 individual fecal samples contributing to each pool. Agreement between the laboratory testing of pools and theoretical calculations based on individual sample results was evaluated. Pooling resulted in fewer L. intracellularis-positive herds (41.9%) compared with testing 20 fecal samples (53.5%). Agreement between the laboratory and the theoretical pools for dichotomized test results was 100% (95% confidence interval: 91.8-100%). For the quantitative test results, Lin concordance correlation coefficient was 0.997. The mean difference between the laboratory testing and the theoretical values was not different from zero (mean difference = 0.039 log10 bacteria/g feces; P = 0.26).
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Acute and short-term chronic testosterone fluctuation effects on glucose homeostasis, insulin sensitivity, and adiponectin: a randomized, double-blind, placebo-controlled, crossover study.
J. Clin. Endocrinol. Metab.
PUBLISHED: 02-28-2014
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Low levels of adiponectin and T in men have been shown to predict development of the metabolic syndrome, but the effects of T on glucose metabolism are incompletely understood and may be influenced either directly or indirectly through changes in body composition or in levels of adiponectin.
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Imaging of carotid artery vessel wall edema using T2-weighted cardiovascular magnetic resonance.
J Cardiovasc Magn Reson
PUBLISHED: 02-10-2014
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Atherothrombosis remains a major health problem in the western world, and carotid atherosclerosis is an important contributor to embolic ischemic strokes. It remains a clinical challenge to identify rupture-prone atherosclerotic plaques before clinical events occur. Inflammation, endothelial injury and angiogenesis are features of vulnerable plaques and may all be associated with plaque edema. Therefore, vessel wall edema, which can be detected by 2D T2-weighted cardiovascular magnetic resonance (CMR), may be used as a dynamic marker of disease activity in the atherosclerotic plaque. However, 2D imaging is limited by low spatial resolution in the slice-select direction compared to 3D imaging techniques. We sought to investigate the ability of novel 3D techniques to detect edema induced in porcine carotid arteries by acute balloon injury compared to conventional 2D T2-weighted black-blood CMR.
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Effects of resveratrol in experimental and clinical non-alcoholic fatty liver disease.
World J Hepatol
PUBLISHED: 01-22-2014
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The prevalence of obesity and related conditions like non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and therapeutic options are limited. Alternative treatment options are therefore intensively sought after. An interesting candidate is the natural polyphenol resveratrol (RSV) that activates adenosinmonophosphate-activated protein kinase (AMPK) and silent information regulation-2 homolog 1 (SIRT1). In addition, RSV has known anti-oxidant and anti-inflammatory effects. Here, we review the current evidence for RSV-mediated effects on NAFLD and address the different aspects of NAFLD and non-alcoholic steatohepatitis (NASH) pathogenesis with respect to free fatty acid (FFA) flux from adipose tissue, hepatic de novo lipogenesis, inadequate FFA ?-oxidation and additional intra- and extrahepatic inflammatory and oxidant hits. We review the in vivo evidence from animal studies and clinical trials. The abundance of animal studies reports a decrease in hepatic triglyceride accumulation, liver weight and a general improvement in histological fatty liver changes, along with a reduction in circulating insulin, glucose and lipid levels. Some studies document AMPK or SIRT1 activation, and modulation of relevant markers of hepatic lipogenesis, inflammation and oxidation status. However, AMPK/SIRT1-independent actions are also likely. Clinical trials are scarce and have primarily been performed with a focus on overweight/obese participants without a focus on NAFLD/NASH and histological liver changes. Future clinical studies with appropriate design are needed to clarify the true impact of RSV treatment in NAFLD/NASH patients.
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Prolonged erythropoietin treatment does not impact gene expression in human skeletal muscle.
Muscle Nerve
PUBLISHED: 01-21-2014
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Introduction: We assessed the presence of erythropoietin receptor (Epo-R) in human skeletal muscle and alterations in gene expression after prolonged erythropoiesis-stimulating agent (ESA). Methods: Nine healthy men were treated with ESA for 10 weeks (Darbepoietin-?). Muscle biopsies were collected before and after treatment. Alterations in gene expression were evaluated by gene array. Western blotting and PCR analysis evaluated Epo-R presence in human skeletal muscle. Results: Very low Epo-R mRNA levels were found, but a new and sensitive antibody did not identify Epo-R protein in human skeletal muscle. The between-subject variation in skeletal muscle gene expression was larger than the changes observed in response to prolonged ESA treatment. Conclusion: Erythropoietin is unlikely to exert direct effects in human skeletal muscle due to a lack of Epo-R protein. Furthermore, prolonged ESA treatment does not seem to exert either direct or indirect effects on skeletal muscle gene expression. © 2014 Wiley Periodicals, Inc.
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Human adipose tissue macrophages are enhanced but changed to an anti-inflammatory profile in obesity.
J Immunol Res
PUBLISHED: 01-20-2014
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Adipose tissue (AT) macrophages are increased in obesity and associated with low grade inflammation. We aimed to characterize the phenotype of AT macrophages in humans in relation to obesity and insulin resistance.
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Herd diagnosis of low pathogen diarrhoea in growing pigs - a pilot study.
Ir Vet J
PUBLISHED: 01-01-2014
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The major indication for antibiotic use in Danish pigs is treatment of intestinal diseases post weaning. Clinical decisions on antibiotic batch medication are often based on inspection of diarrhoeic pools on the pen floor. In some of these treated diarrhoea outbreaks, intestinal pathogens can only be demonstrated in a small number of pigs within the treated group (low pathogen diarrhoea). Termination of antibiotic batch medication in herds suffering from such diarrhoea could potentially reduce the consumption of antibiotics in the pig industry. The objective of the present pilot study was to suggest criteria for herd diagnosis of low pathogen diarrhoea in growing pigs. Data previously collected from 20 Danish herds were used to create a case series of clinical diarrhoea outbreaks normally subjected to antibiotic treatment. In the present study, these diarrhoea outbreaks were classified as low pathogen (<15% of the pigs having bacterial intestinal disease) (n =5 outbreaks) or high pathogen (?15% of the pigs having bacterial intestinal disease) (n =15 outbreaks). Based on the case series, different diagnostic procedures were explored, and criteria for herd diagnosis of low pathogen diarrhoea were suggested. The effect of sampling variation was explored by simulation.
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Electron transport through a diazonium-based initiator layer to covalently attached polymer brushes of ferrocenylmethyl methacrylate.
Langmuir
PUBLISHED: 10-21-2013
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A versatile method based on electrografting of aryldiazonium salts was used to introduce covalently attached initiators for atom transfer radical polymerization (ATRP) on glassy carbon surfaces. Polymer brushes of ferrocenylmethyl methacrylate were prepared from the surface-attached initiators, and these films were thoroughly analyzed using various techniques, including X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRRAS), ellipsometry, and electrochemistry. Of particular interest was the electrochemical characterization of the electron transfer through the diazonium-based initiator layer to the redox centers in the polymer brush films. It was found that the apparent rate constant of electron transfer decreases exponentially with the dry-state thickness of this layer. To investigate the electron transfer in the brushes themselves, scanning electrochemical microscopy (SECM) was applied, thereby allowing the effect from the initiator layer to be excluded. The unusual transition feature of the approach curves recorded suggests that an initial fast charge transfer to the outermost-situated ferrocenyl groups is followed by a slower electron transport involving the neighboring redox units.
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Control of ribosome traffic by position-dependent choice of synonymous codons.
Phys Biol
PUBLISHED: 10-08-2013
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Messenger RNA (mRNA) encodes a sequence of amino acids by using codons. For most amino acids, there are multiple synonymous codons that can encode the amino acid. The translation speed can vary from one codon to another, thus there is room for changing the ribosome speed while keeping the amino acid sequence and hence the resulting protein. Recently, it has been noticed that the choice of the synonymous codon, via the resulting distribution of slow- and fast-translated codons, affects not only on the average speed of one ribosome translating the mRNA but also might have an effect on nearby ribosomes by affecting the appearance of traffic jams where multiple ribosomes collide and form queues. To test this context effect further, we here investigate the effect of the sequence of synonymous codons on the ribosome traffic by using a ribosome traffic model with codon-dependent rates, estimated from experiments. We compare the ribosome traffic on wild-type (WT) sequences and sequences where the synonymous codons were swapped randomly. By simulating translation of 87 genes, we demonstrate that the WT sequences, especially those with a high bias in codon usage, tend to have the ability to reduce ribosome collisions, hence optimizing the cellular investment in the translation apparatus. The magnitude of such reduction of the translation time might have a significant impact on the cellular growth rate and thereby have importance for the survival of the species.
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Molecular crowding limits translation and cell growth.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-30-2013
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Bacterial growth is crucially dependent on protein synthesis and thus on the cellular abundance of ribosomes and related proteins. Here, we show that the slow diffusion of the bulky tRNA complexes in the crowded cytoplasm imposes a physical limit on the speed of translation, which ultimately limits the rate of cell growth. To study the required allocation of ancillary translational proteins to alleviate the effect of molecular crowding, we develop a model for cell growth based on a coarse-grained partitioning of the proteome. We find that coregulation of ribosome- and tRNA-affiliated proteins is consistent with measured growth-rate dependencies and results in near-optimal allocation over a broad range of growth rates. The analysis further resolves a long-standing controversy in bacterial growth physiology concerning the growth-rate dependence of translation speed and serves as a caution against premature identification of phenomenological parameters with mechanistic processes.
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Growth hormone-induced insulin resistance in human subjects involves reduced pyruvate dehydrogenase activity.
Acta Physiol (Oxf)
PUBLISHED: 08-13-2013
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Insulin resistance induced by growth hormone (GH) is linked to promotion of lipolysis by unknown mechanisms. We hypothesized that suppression of the activity of pyruvate dehydrogenase in the active form (PDHa) underlies GH-induced insulin resistance similar to what is observed during fasting.
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Whole body metabolic effects of prolonged endurance training in combination with erythropoietin treatment in humans: a randomized placebo controlled trial.
Am. J. Physiol. Endocrinol. Metab.
PUBLISHED: 08-06-2013
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Erythropoietin (Epo) administration improves aerobic exercise capacity and insulin sensitivity in renal patients and also increases resting energy expenditure (REE). Similar effects are observed in response to endurance training. The aim was to compare the effects of endurance training with erythropoiesis-stimulating agent (ESA) treatment in healthy humans. Thirty-six healthy untrained men were randomized to 10 wk of either: 1) placebo (n = 9), 2) ESA (n = 9), 3) endurance training (n = 10), or 4) ESA and endurance training (n = 8). In a single-blinded design, ESA/placebo was injected one time weekly. Training consisted of biking for 1 h at 65% of wattmax three times per week. Measurements performed before and after the intervention were as follows: body composition, maximal oxygen uptake, insulin sensitivity, REE, and palmitate turnover. Uncoupling protein 2 (UCP2) mRNA levels were assessed in skeletal muscle. Fat mass decreased after training (P = 0.003), whereas ESA induced a small but significant increase in intrahepatic fat (P = 0.025). Serum free fatty acid (FFA) levels and palmitate turnover decreased significantly in response to training, whereas the opposite pattern was found after ESA. REE corrected for lean body mass increased in response to ESA and training, and muscle UCP2 mRNA levels increased after ESA (P = 0.035). Insulin sensitivity increased only after training (P = 0.011). In conclusion: 1) insulin sensitivity is not improved after ESA treatment despite improved exercise capacity, 2) the calorigenic effects of ESA may be related to increased UCP2 gene expression in skeletal muscle, and 3) training and ESA exert opposite effects on lipolysis under basal conditions, increased FFA levels and liver fat fraction was observed after ESA treatment.
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Resveratrol in metabolic health: an overview of the current evidence and perspectives.
Ann. N. Y. Acad. Sci.
PUBLISHED: 07-17-2013
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In the search for novel preventive and therapeutic modalities in the management of metabolic diseases and obesity, resveratrol has attracted great attention over the past decades. Preclinical trials suggest that resveratrol mimics the metabolic effects of calorie restriction (CR) via activation of silent mating type information regulation 2 homolog 1 (SIRT1). In experimental animals, this potential translates into prevention or improvement of glucose metabolism, anti-inflammation, cancer, and nonalcoholic fatty liver disease. Moreover, and in accordance with CR, supplementation with resveratrol promotes longevity in several primitive species and protects against diet-induced metabolic abnormalities in rodents. Despite the substantial preclinical evidence, human clinical data are very scarce, and even though the compound is widely distributed as an over-the-counter human nutritional supplement, its therapeutic rationale has not been well characterized. In this review, we provide a brief overview of the field and discuss the future scientific directions of resveratrol research.
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Direct Effects of TNF-? on Local Fuel Metabolism and Cytokine Levels in the Placebo-Controlled, Bilaterally Infused Human Leg: Increased Insulin Sensitivity, Increased Net Protein Breakdown, and Increased IL-6 Release.
Diabetes
PUBLISHED: 07-08-2013
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Tumor necrosis factor-? (TNF-?) has widespread metabolic actions. Systemic TNF-? administration, however, generates a complex hormonal and metabolic response. Our study was designed to test whether regional, placebo-controlled TNF-? infusion directly affects insulin resistance and protein breakdown. We studied eight healthy volunteers once with bilateral femoral vein and artery catheters during a 3-h basal period and a 3-h hyperinsulinemic-euglycemic clamp. One artery was perfused with saline and one with TNF-?. During the clamp, TNF-? perfusion increased glucose arteriovenous differences (0.91 ± 0.17 vs. 0.74 ± 0.15 mmol/L, P = 0.012) and leg glucose uptake rates. Net phenylalanine release was increased by TNF-? perfusion with concomitant increases in appearance and disappearance rates. Free fatty acid kinetics was not affected by TNF-?, whereas interleukin-6 (IL-6) release increased. Insulin and protein signaling in muscle biopsies was not affected by TNF-?. TNF-? directly increased net muscle protein loss, which may contribute to cachexia and general protein loss during severe illness. The finding of increased insulin sensitivity, which could relate to IL-6, is of major clinical interest and may concurrently act to provide adequate tissue fuel supply and contribute to the occurrence of systemic hypoglycemia. This distinct metabolic feature places TNF-? among the rare insulin mimetics of human origin.
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The Macrophage-Specific Serum Marker, Soluble CD163, Is Increased in Obesity and Reduced After Dietary-Induced Weight Loss.
Obesity (Silver Spring)
PUBLISHED: 07-02-2013
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Objective: Soluble CD163 (sCD163) is a new macrophage-specific serum marker elevated in inflammatory conditions. sCD163 is elevated in obesity and found to be a strong predictor of the development of type 2 diabetes. We investigated whether dietary intervention and moderate exercise was related to changes in sCD163 and how sCD163 is associated to insulin resistance in obesity. Design and Methods: Ninety-six obese subjects were enrolled: 62 followed a very low energy diet (VLED) program for 8 weeks followed by 3-4 weeks of weight stabilization, 20 followed a moderate exercise program for 12 weeks, and 14 were included without any intervention. Fasting blood samples and anthropometric measures were taken at baseline and after intervention. Thirty-six lean subjects were included in a control group. Results: sCD163 was significantly higher in obese subjects (2.3 ± 1.0 mg/l) compared with lean (1.6 ± 0.4 mg/l, P < 0.001). Weight loss (11%) induced by VLED resulted in a reduction and partial normalization of sCD163 to 2.0 ± 0.9 mg/l (P < 0.001). Exercise for 12 weeks had no effect on sCD163. At baseline, sCD163 was significantly correlated with BMI (r = 0.46), waist circumference (r = 0.40), insulin resistance measured by the homeostasis model assessment (HOMA-IR; r = 0.41; all P < 0.001), and the leptin-to-adiponectin ratio (r = 0.28, P < 0.05). In a multivariate linear regression analysis with various inflammatory markers, sCD163 (? = 0.25), adiponectin (? = -0.24), and high sensitivity C-reactive protein (hs-CRP; ? = 0.20) remained independently and significantly associated to HOMA-IR (all P < 0.05). After further adjustment for waist circumference, only sCD163 was associated with HOMA-IR (P < 0.05). Conclusion: The macrophage-specific serum marker sCD163 is increased in obesity and partially normalized by dietary-induced weight loss but not by moderate exercise. Furthermore, we confirm that sCD163 is a good marker for obesity-related insulin resistance.
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A cytochrome P450 phenotyping cocktail causing unexpected adverse reactions in female volunteers.
Eur. J. Clin. Pharmacol.
PUBLISHED: 06-11-2013
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A four-drug cytochrome P450 (CYP) phenotyping cocktail was developed to rapidly and safely determine CYP2D6, CYP2C19, CYP2C9 and CYP1A2 enzyme activity and phenotype.
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Ghrelin- and GH-induced insulin resistance: no association with retinol-binding protein-4.
Endocr Connect
PUBLISHED: 06-01-2013
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Supraphysiological levels of ghrelin and GH induce insulin resistance. Serum levels of retinol-binding protein-4 (RBP4) correlate inversely with insulin sensitivity in patients with type 2 diabetes. We aimed to determine whether ghrelin and GH affect RBP4 levels in human subjects.
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Gene expression in skeletal muscle after an acute intravenous GH bolus in human subjects: identification of a mechanism regulating ANGPTL4.
J. Lipid Res.
PUBLISHED: 04-20-2013
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Growth hormone (GH) acutely stimulates lipolysis and fat oxidation, a process that operates postabsorptively and involves activation of the JAK-STAT pathway in the target tissue; no in vivo data exist regarding subsequent GH-regulated gene transcription. We obtained serum samples and muscle biopsies in human subjects before and 2 h after administration of a GH bolus. A significant (~75%) elevation in serum FFA levels was recorded post GH. Microarray identified 79 GH-regulated genes in muscle. With qRT-PCR, we then examined the expression of selected genes in the presence and absence of glucose-induced suppression of lipolysis. Four genes involved in the JAK-STAT5 signaling pathway were regulated by GH, including SOCS1-3 and CISH, in addition to three genes associated with insulin action: NF?B1A, PIK3C2B, and PRKAG2. The gene encoding ANGPTL4, a protein involved in lipolysis and suppression of LPL activity, exhibited the most pronounced upregulation (5.6-fold) after GH, which was abrogated by concomitant suppression of lipolysis. Therefore, the GH-induced stimulation of ANGPTL4 gene expression seems secondary to induction of lipolysis. This new concept implies that abundant supply of circulating FFA decreases the need for alternative triglyceride-derived FFA through distinct inhibition of LPL mediated by increased ANGPTL4 gene expression in human muscle.
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On electrogenerated acid-facilitated electrografting of aryltriazenes to create well-defined aryl-tethered films.
Langmuir
PUBLISHED: 04-15-2013
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The mechanism of electrogenerated acid-facilitated electrografting (EGAFE) of the aryltriazene, 4-(3,3-dimethyltriaz-1-enyl)benzyl-1-ferrocene carboxylate, was studied in detail using electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry. The measurements support the previously suggested mechanism that electrochemical oxidation of the EGA agent (i.e., N,N-diphenylhydrazine) occurs on the forward oxidative sweep to generate protons, which in turn protonate the aryltriazene to form the corresponding aryldiazonium salt close to the electrode surface. On the reverse sweep, the electrochemical reduction of the aryldiazonium salt takes place, resulting in the electrografting of aryl groups. The EGAFE-generated film consists of a densely packed layer of ferrocenyl groups with nearly ideal electrochemical properties. The uncharged grafted film contains no solvent and electrolyte, but counterions and solvent can easily enter and be accommodated in the film upon charging. It is shown that all ferrocene moieties present in the multilayered film are electrochemically active, suggesting that the carbon skeleton possesses a sufficiently high flexibility to allow the occurrence of fast electron transfers between the randomly located redox stations. In comparison, EQCM measurements on aryldiazonium-grafted films reveal that they have a substantially smaller electrolyte uptake during charging and that they contain only 50% electroactive ferrocenyl groups relative to weight. Hence, half of these films consist of entrapped supporting electrolyte/solvent and/or simply electrochemically inactive material due to solvent inaccessibility.
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Direct effects of locally administered lipopolysaccharide on glucose, lipid, and protein metabolism in the placebo-controlled, bilaterally infused human leg.
J. Clin. Endocrinol. Metab.
PUBLISHED: 03-29-2013
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Accumulating evidence suggests that chronic exposure to lipopolysaccharide (LPS, endotoxin) may create a constant low-grade inflammation, leading to insulin resistance and diabetes. All previous human studies assessing the metabolic actions of LPS have used systemic administration, making discrimination between direct and indirect effects impossible.
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The effect of high-dose vitamin d supplementation on calciotropic hormones and bone mineral density in obese subjects with low levels of circulating 25-hydroxyvitamin d: results from a randomized controlled study.
Calcif. Tissue Int.
PUBLISHED: 03-27-2013
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Low levels of 25-hydroxyvitamin D (25OHD) are associated with increased bone turnover and risk of fractures. Plasma 25OHD is inversely related to body mass index, and vitamin D deficiency is common in obesity. We aimed to determine whether vitamin D supplementation affects bone turnover and bone mineral density (BMD) in obese subjects. Fifty-two healthy obese men and women aged 18-50 years with plasma 25OHD levels below 50 nmol/L were randomized to 7,000 IU of cholecalciferol daily or placebo for 26 weeks. We measured plasma levels of 25OHD, parathyroid hormone (PTH), and markers of bone turnover, as well as BMD at the hip, spine, forearm, and whole body. Compared with placebo, treatment with cholecalciferol increased mean plasma 25OHD from 35 to 110 nmol/L (p < 0.00001) and significantly decreased PTH (p < 0.05). BMD increased significantly at the forearm by 1.6 ± 0.7 % (p = 0.03). The bone resorption marker C-terminal telopetide of type 1 collagen (CTX) decreased borderline significantly in the cholecalciferol group compared with the placebo group (p = 0.07). Changes in plasma 25OHD correlated inversely with changes in plasma levels of bone-specific alkaline phosphatase (r = -0.38, p = 0.01) and CTX (r = -0.33, p = 0.03). Changes in CTX correlated inversely with changes in spine BMD (r = -0.45, p = 0.04). Increasing circulating 25OHD levels by cholecalciferol treatment is of importance to bone health in young obese subjects as increased levels of 25OHD are associated with a decrease in both PTH and bone turnover and with an increase in BMD at the forearm.
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Diagnostic performance of fecal quantitative real-time polymerase chain reaction for detection of Lawsonia intracellularis-associated proliferative enteropathy in nursery pigs.
J. Vet. Diagn. Invest.
PUBLISHED: 03-27-2013
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Quantitative polymerase chain reaction (qPCR) tests for detection and quantification of Lawsonia intracellularis in feces from pigs have been developed. The objective of the current study was to evaluate the diagnostic performance of a fecal qPCR test for detection of nursery pigs with L. intracellularis-associated proliferative enteropathy (PE) under field conditions. Furthermore, the diagnostic performance for different subpopulations of pigs was investigated, including pigs infected or noninfected with Porcine circovirus-2, Brachyspira pilosicoli, and Escherichia coli. The diagnostic performance was evaluated in terms of diagnostic sensitivity and specificity. Data from pigs originating from 20 herds with antibiotic treatment requiring diarrhea outbreaks from a prior study were reused. Before treatment, pigs were randomly selected for histological and immunohistochemical examination of intestinal segments and fecal quantification of L. intracellularis by qPCR. A total of 313 pigs (157 without diarrhea, 156 with diarrhea) were included in the statistical analysis, and 37 pigs (11.8%) were classified as PE positives (defined as proliferative histological lesions in combination with L. intracellularis demonstration by immunohistochemistry). Lawsonia intracellularis was detected by qPCR in feces from 91 pigs (29.1%). A nonparametric receiver operating characteristic (ROC) analysis provided an area under the ROC curve (0.93) and an optimal cutoff value of 4.8 log10 L. intracellularis bacteria/g feces. This cutoff provided a diagnostic sensitivity of 0.84 and diagnostic specificity of 0.93. The diagnostic sensitivity and specificity were significantly different between herds (P < 0.0001). Numerically, diagnostic sensitivity and specificity were different between subpopulations of pigs, but no significant differences were demonstrated.
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Electrochemical polymerization of allylamine copolymers.
Langmuir
PUBLISHED: 03-04-2013
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We describe for the first time the electro-oxidative synthesis and passivating properties of surface films of poly(allylamine) and copolymers of allylamine and diallylamine. Cyclic voltammetry and impedance spectra show that the films exhibit high charge-transfer resistance and that the addition of diallylamine causes improvements in the compactness and stability toward swelling of the films when compared to both allylamine and diallyamine, leading to coatings with high charge-transfer resistance up to 70 M?. We also show that removing oxygen before the polymerization further improves the films passivating properties.
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Surface grafted glycopolymer brushes to enhance selective adhesion of HepG2 cells.
J Colloid Interface Sci
PUBLISHED: 02-27-2013
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This work demonstrates the application of carbohydrate based methacrylate polymer brush, poly(2-lactobionamidoethyl methacrylate), for the purpose of cell adhesion studies. The first part of the work illustrates the effects of the structure of the aminosilane based ATRP initiator layer on the polymerization kinetics of 2-lactobionamidoethyl methacrylate) (LAMA) monomer on thermally oxidized silicon wafer. Both monolayer and multilayered aminosilane precursor layers have been prepared followed by reaction with 2-bromoisobutyrylbromide to form the ATRP initiator layer. It is inferred from the kinetic studies that the rate of termination is low on a multilayered initiator layer compared to a disordered monolayer structure. However both initiator types results in similar graft densities. Furthermore, it is shown that thick comb-like poly(LAMA) brushes can be constructed by initiating a second ATRP process on a previously formed poly(LAMA) brushes. The morphology of human hepatocellular carcinoma cancer cells (HepG2) on the comb-like poly(LAMA) brush layer has been studied. The fluorescent images of the HepG2 cells on the glycopolymer brush surface display distinct protrusions that extend outside of the cell periphery. On the other hand the cells on bare glass substrate display spheroid morphology. Further analysis using ToF-SIMS imaging shows that the HepG2 cells on glycopolymer surfaces is enriched with protein fragment along the cell periphery which is absent in the case of cells on bare glass substrate. It is suggested that the interaction of the galactose units of the polymer brush with the asialoglycoprotein receptor (ASGPR) of HepG2 cells has resulted in the protein enrichment along the cell periphery.
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Effects of a meal rich in medium-chain saturated fat on postprandial lipemia in relatives of type 2 diabetics.
Nutrition
PUBLISHED: 01-28-2013
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Patients with type 2 diabetes and their relatives (REL) have increased risk for cardiovascular disease (CVD). Postprandial triglyceridemia (PPL), which is influenced by diet, is an independent risk factor for CVD. Little is known about the effects of medium-chain saturated fatty acids (medium-chain SFA) on PPL and gene expression in REL. The objective of this study was to test the hypothesis that medium-chain SFA cause larger PPL response in REL compared with controls (CON) and have a differential effect on circulating incretins and ghrelin and gene expression in muscle and adipose tissue in REL and CON.
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Interactions of acetylcholine binding site residues contributing to nicotinic acetylcholine receptor gating: role of residues Y93, Y190, K145 and D200.
J. Mol. Graph. Model.
PUBLISHED: 01-25-2013
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The nicotinic acetylcholine receptor exhibits multiple conformational states, resting (channel closed), active (channel open) and desensitized (channel closed). The resting state may be distinguished from the active and desensitized states by the orientation of loop C in the extracellular ligand binding domain (LBD). Homology modeling was used to generate structures of the Torpedo californica ?2??? nAChR that initially represent the resting state (loop C open) and the desensitized state (loop C closed). Molecular dynamics (MD) simulations were performed on the extracellular LBD on each nAChR conformational state, with and without the agonist anabaseine present in each binding site (the ?? and the ?? sites). Three MD simulations of 10ns each were performed for each of the four conditions. Comparison of dynamics revealed that in the presence of agonist, loop C was drawn inward and attains a more stable conformation. Examination of side-chain interactions revealed that residue ?Y190 exhibited hydrogen-bonding interactions either with residue ?Y93 in the ligand binding site or with residue ?K145 proximal to the binding site. ?K145 also exhibited side chain (salt bridge) interactions with ?D200 and main chain interactions with ?Y93. Residues ?W149, ?Y198, ?Y116/?T119, ?L118/?L121 and ?L108/?L111 appear to play the role of stabilizing ligand in the binding site. In MD simulations for the desensitized state, the effect of ligand upon the interactions among ?K145, ?Y190, and ?Y93 as well as ligand-hydrogen-bonding to ?W149 were more pronounced at the ?? interface than at the ?? interface. Differences in affinity for the desensitized state were determined experimentally to be 10-fold. The changes in side chain interactions observed for the two conformations and induced by ligand support a model wherein hydrogen bond interactions between ?D200 and ?Y93 are broken and rearrange to form a salt-bridge between ?K145 and ?D200 and hydrogen bond interactions between ?Y93 and ?Y190 and between ?K145 and ?Y190.
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Resveratrol has inhibitory effects on the hypoxia-induced inflammation and angiogenesis in human adipose tissue in vitro.
Eur J Pharm Sci
PUBLISHED: 01-21-2013
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Hypoxia modulates the production of proteins involved in e.g. inflammation, angiogenesis and glucose utilization and hypoxia may therefore be an important factor underlying adipose tissue dysfunction in obesity. Resveratrol (RSV) is a natural polyphenolic compound and has been shown to have powerful anti-inflammatory effects and beneficial effects on several obesity-related complications. Thus, in the present study we investigated whether RSV has effects on hypoxic markers (GLUT-1, VEGF), hypoxia-induced key markers of inflammation (IL8, IL6), and leptin in human adipose tissue in vitro. Hypoxia was induced by incubating human adipose tissue fragments with 1% O2 for 24h as compared to 21% O2 The gene expressions were investigated by RT-PCR and protein release by Elisa. Hypoxia increases the expression of glucose transporter-1 (GLUT-1) (19-fold, p<0.001), vascular endothelial growth factor (VEGF) (10-fold, p<0.05), interleukin-8 (IL8) (8-fold, p<0.05), interleukin-6 (IL6) (5-fold, p<0.05) and leptin (9-fold). The protein levels of VEGF released to the medium was increased (8-fold, p<0.01) by hypoxia. RSV dose-dependently inhibited several of these hypoxia-induced expressions and at a concentration of 50 ?M RSV almost completely inhibited the hypoxic responses at the above mentioned gene expression levels (p<0.05-p<0.001) and significantly attenuated the hypoxia-induced protein releases by 50-60%. These results demonstrate that hypoxia induces extensive changes in human adipose tissue in the expression and release of inflammation and angiogenesis-related adipokines. In addition the inhibition of hypoxia-mediated inflammation and angiogenesis might represent a novel mechanism of RSV in preventing obesity-related pathologies.
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Acute exercise increases circulating inflammatory markers in overweight and obese compared with lean subjects.
Eur. J. Appl. Physiol.
PUBLISHED: 01-16-2013
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The primary aim of the present study was to investigate if overweight and obese compared to lean individuals displayed differences in levels of inflammatory markers in circulation, skeletal muscle (SM) and adipose tissue (AT) after acute exercise. Fifteen lean (BMI: 22.4 ± 2 kg/m(2)) and 16 overweight or obese (BMI 31.8 ± 3 kg/m(2)) individuals were included in the study. They completed 120 min of ergometer bicycling at 55-60 % of maximal heart rate. Blood samples were obtained at baseline (T = 0), after 60 (T = 60) and 120 min of exercise (T = 120), and analyzed using an ELISA method. SM and AT biopsies were obtained at T0 and T120, and mRNA expression was investigated using a Real-time RT-PCR method. Circulating IL-6, TNF-?, IL-8, and IL-15 all increased at T = 120 min (p < 0.01). Circulating IL-6 and IL-15 increased in all subjects at T = 120 min (p < 0.01), but only the increase of IL-6 was significantly higher in overweight and obese subjects (p < 0.05), and was positively correlated with body fat percentage (p < 0.01). Circulating IL-8 and TNF-? were increased in overweight and obese (p < 0.05) but not in lean subjects. Acute exercise induced an increase in IL-6 mRNA expression in SM biopsies (p < 0.05). IL-6 as well as adiponectin mRNA expression was increased in AT biopsies (p < 0.05); however, no effect of body weight was found. The findings suggest that the systemic inflammatory response to acute exercise is different in lean compared to overweight and obese subjects, with a more pronounced increase in inflammatory markers (e.g., IL-6, IL-8, and TNF-?) in overweight and obese individuals.
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Sucrose-sweetened beverages increase fat storage in the liver, muscle, and visceral fat depot: a 6-mo randomized intervention study.
Am. J. Clin. Nutr.
PUBLISHED: 12-28-2011
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The consumption of sucrose-sweetened soft drinks (SSSDs) has been associated with obesity, the metabolic syndrome, and cardiovascular disorders in observational and short-term intervention studies. Too few long-term intervention studies in humans have examined the effects of soft drinks.
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Redox grafting of diazotated anthraquinone as a means of forming thick conducting organic films.
Langmuir
PUBLISHED: 12-16-2011
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Thick conductive layers containing anthraquinone moieties are covalently immobilized on gold using redox grafting of the diazonium salt of anthraquinone (i.e., 9,10-dioxo-9,10-dihydroanthracene-1-diazonium tetrafluoroborate). This grafting procedure is based on using consecutive voltammetric sweeping and through this exploiting fast electron transfer reactions that are mediated by the anthraquinone redox moieties in the film. The fast film growth, which is followed by infrared reflection absorption spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, ellipsometry, and coverage calculation, results in a mushroom-like structure. In addition to varying the number of sweeps, layer thickness control can easily be exerted through appropriate choice of the switching potential and sweep rate. It is shown that the grafting of the diazonium salt is essentially a diffusion-controlled process but also that desorption of physisorbed material during the sweeping process is essentially for avoiding blocking of the film due to clogging of the electrolyte channels in the film. In general, sweep rates higher than 0.5 V s(-1) are required if thick, porous, and conducting films should be formed.
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Determination of acute vascular injury and edema in porcine carotid arteries by T2 weighted cardiovascular magnetic resonance.
Int J Cardiovasc Imaging
PUBLISHED: 08-04-2011
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Inflammation plays an essential role for destabilization and rupture of carotid atherosclerotic plaques causing embolic ischemic stroke. Inflammation of the vessel wall may result in the formation of edema. This study investigated whether edema in the carotid artery wall induced by acute balloon injury could be detected by cardiovascular magnetic resonance (CMR) using a T2-weighted short-tau inversion recovery sequence (T2-STIR). Edema was induced unilaterally by balloon injury in the carotid artery of six pigs. Four to nine days (average six) post injury, the carotid arteries were assessed by T2-STIR and multi-contrast weighted sequences. CMR images were matched to histopathology, validated against Evans blue, and correlated with the amount of fibrinogen in the arterial wall used as an edema marker. T2-STIR images showed that the carotid signal intensity (SI) divided by the sternocleid muscle SI of the injured carotid artery was on average 223% (P = 0.03) higher than that of the uninjured carotid artery. Using a threshold value of 4SD, T2-STIR detected edema in the vessel wall (i.e., hyperintense signal intensity) with a sensitivity of 100% and a specificity of 75%. Agreement was observed between carotid artery wall hyperintense signal intensity and Evans blue uptake (X(2) = 17.1, P < 0.001). The relative signal intensity correlated in a linear fashion with the amount of fibrinogen detected by histopathology (? = 0.9, P < 0.001). None of the multi-contrast weighted sequences detected edema in the carotid artery with reasonable sensitivity or specificity. T2-STIR CMR allowed carotid artery wall edema detection and may therefore be a useful non-invasive diagnostic tool for determination of inflammatory activity in the carotid artery wall.
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Effect of industrially produced trans fat on markers of systemic inflammation: evidence from a randomized trial in women.
J. Lipid Res.
PUBLISHED: 07-27-2011
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Consumption of industrially produced trans fatty acids (IP-TFA) has been positively associated with systemic markers of low-grade inflammation and endothelial dysfunction in cross-sectional studies, but results from intervention studies are inconclusive. Therefore, we conducted a 16 week double-blind parallel intervention study with the objective to examine the effect of IP-TFA intake on biomarkers of inflammation, oxidative stress, and endothelial dysfunction. Fifty-two healthy overweight postmenopausal women (49 completers) were randomly assigned to receive either partially hydrogenated soybean oil (15.7 g/day IP-TFA) or control oil without IP-TFA. After 16 weeks, IP-TFA intake increased baseline-adjusted serum tumor necrosis factor (TNF) ? by 12% [95% confidence interval (CI): 5-20; P = 0.002] more in the IP-TFA group compared with controls. Plasma soluble TNF receptors 1 and 2 were also increased by IP-TFA [155 pg/ml (CI: 63-247); P < 0.001 and 480 pg/ml (CI: 72-887); P = 0.02, respectively]. Serum C-reactive protein, interleukin (IL) 6 and adiponectin and subcutaneous abdominal adipose tissue mRNA expression of IL6, IL8, TNF?, and adiponectin as well as ceramide content were not affected by IP-TFA, nor was urinary 8-iso-prostaglandin-F(2?). In conclusion, this dietary trial indicates that the mechanisms linking dietary IP-TFA to cardiovascular disease may involve activation of the TNF? system.
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Differential effects of dietary protein sources on postprandial low-grade inflammation after a single high fat meal in obese non-diabetic subjects.
Nutr J
PUBLISHED: 06-27-2011
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Obesity is a state of chronic low-grade inflammation. Chronic low-grade inflammation is associated with the pathophysiology of both type-2 diabetes and atherosclerosis. Prevention or reduction of chronic low-grade inflammation may be advantageous in relation to obesity related co-morbidity. In this study we investigated the acute effect of dietary protein sources on postprandial low-grade inflammatory markers after a high-fat meal in obese non-diabetic subjects.
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Acute peripheral metabolic effects of intraarterial leg infusion of somatostatin in healthy young men.
J. Clin. Endocrinol. Metab.
PUBLISHED: 06-01-2011
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Evidence suggests that somatostatin not only inhibits the secretion of GH but also suppresses GH action in peripheral tissues.
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Fasting, but not exercise, increases adipose triglyceride lipase (ATGL) protein and reduces G(0)/G(1) switch gene 2 (G0S2) protein and mRNA content in human adipose tissue.
J. Clin. Endocrinol. Metab.
PUBLISHED: 05-25-2011
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Fasting and exercise are characterized by increased lipolysis, but the underlying mechanisms are not fully understood.
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GLUT4 and UBC9 protein expression is reduced in muscle from type 2 diabetic patients with severe insulin resistance.
PLoS ONE
PUBLISHED: 03-14-2011
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Subgroups of patients with type 2 diabetes mellitus demand large insulin doses to maintain euglycemia. These patients are characterized by severe skeletal muscle insulin resistance and the underlying pathology remains unclear. The purpose of this study was to examine protein expression of the principal glucose transporter, GLUT4, and associated proteins in skeletal muscle from type 2 diabetic patients characterized by severe insulin resistance.
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Determination of edema in porcine coronary arteries by T2 weighted cardiovascular magnetic resonance.
J Cardiovasc Magn Reson
PUBLISHED: 03-14-2011
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Inflammation plays a pivotal role in all stages of atherosclerosis. Since edema is known to be an integral part of inflammation, a noninvasive technique that can identify edema in the coronary artery wall may provide unique information regarding plaque activity. In this study, we aimed to determine whether edema induced in porcine coronary arteries by balloon injury could be reliably detected by cardiovascular magnetic resonance (CMR) using a water sensitive T2-weighted short tau inversion recovery sequence (T2-STIR). We also aimed to compare these results to those of conventional T2-weighted (T2W) imaging.
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Evaluation of a microwave method for dry matter determination in faecal samples from weaned pigs with or without clinical diarrhoea.
Prev. Vet. Med.
PUBLISHED: 03-11-2011
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Microwave drying as a procedure for determination of faecal dry matter in weaned pigs was evaluated and clinical relevant cut-off values between faecal consistency scores were determined. Repeatability and reproducibility were evaluated. Overall coefficient of variation was 0.03. The 95% confidence limits for any future faecal subsample examined by any operator in any replica were ± 0.85% faecal dry matter. Robustness in relation to weight of wet faeces was evaluated. The weight categories were 0.5, 1.0, 1.5, 2.0 and 3.0 g. Samples of 0.5 g gave significantly different mean faecal dry matter content compared to weighing of 1.0-3.0 g. Agreement with freeze-drying was evaluated. Lins concordance correlation coefficient was 0.94. On average the faecal dry matter values was 1.7% (SD=1.99%) higher in freeze dried compared to micro waved samples. Non-parametric ROC analyses were used to determine optimal faecal dry matter cut-off values for clinical faecal consistency scores. The 4 consistency scores were score 1=firm and shaped, score 2=soft and shaped, score 3=loose and score 4=watery. The cut-off values were score 1: faecal dry matter content >19.5%, score 2: faecal dry matter content ? 19.5% and >18.0%, score 3: faecal dry matter content ? 18.0% and >11.3%, score 4: faecal dry matter content ? 11.3%. In conclusion, the microwave procedure has an acceptable repeatability/reproducibility and good agreement with freeze drying can be expected. A minimum of 1.0 g of wet faeces must be used for analyses. Faecal dry matter cut-off values between 4 different clinical consistency scores were determined.
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Rosiglitazone decreases bone mass and bone marrow fat.
J. Clin. Endocrinol. Metab.
PUBLISHED: 03-02-2011
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Activation of peroxisome proliferator-activated receptor-? is believed to promote adipocyte development from mesenchymal stem cells in the bone marrow at the expense of osteoblasts, leading to decreased bone mineral density (BMD) and increased marrow fat.
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Combining aryltriazenes and electrogenerated acids to create well-defined aryl-tethered films and patterns on surfaces.
J. Am. Chem. Soc.
PUBLISHED: 02-28-2011
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Immobilization of submonolayers to 4-5 multilayers of organic molecules on carbon surfaces can be performed by in situ generation of aryl radicals from aryltriazenes. The central idea consists of oxidatively forming an electrogenerated acid of N,N-diphenylhydrazine to convert the aryltriazene to the corresponding diazonium salt in the diffusion layer of the electrode. In a second step, the diazonium salt is reduced at the same electrode to give a surface of covalently attached aryl groups. In this manner, various moieties tethered to the aryl groups can be immobilized on the surface. Here a ferrocenyl group was introduced as redox marker, the electrochemical signal of which is extraordinarily well-defined. This behavior is independent of film thickness, the latter being easily controlled by the number of repetitive cycles performed. It is also demonstrated that the new approach is suitable for patterning of surfaces using scanning electrochemical microscopy.
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CMR assessment of endothelial damage and angiogenesis in porcine coronary arteries using gadofosveset.
J Cardiovasc Magn Reson
PUBLISHED: 01-26-2011
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Endothelial damage and angiogenesis are essential for atherosclerotic plaque development and destabilization. We sought to examine whether contrast enhanced cardiovascular magnetic resonance (CMR) using gadofosveset could show endothelial damage and neovessel formation in balloon injured porcine coronary arteries.
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The functional half-life of an mRNA depends on the ribosome spacing in an early coding region.
J. Mol. Biol.
PUBLISHED: 01-11-2011
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Bacterial mRNAs are translated by closely spaced ribosomes and degraded from the 5-end, with half-lives of around 2 min at 37 °C in most cases. Ribosome-free or "naked" mRNA is known to be readily degraded, but the initial event that inactivates the mRNA functionally has not been fully described. Here, we characterize a determinant of the functional stability of an mRNA, which is located in the early coding region. Using literature values for the mRNA half-lives of variant lacZ mRNAs in Escherichia coli, we modeled how the ribosome spacing is affected by the translation rate of the individual codons. When comparing the ribosome spacing at various segments of the mRNA to its functional half-life, we found a clear correlation between the functional mRNA half-life and the ribosome spacing in the mRNA region approximately between codon 20 and codon 45. From this finding, we predicted that inserts of slowly translated codons before codon 20 or after codon 45 should shorten or prolong, respectively, the functional mRNA half-life by altering the ribosome density in the important region. These predictions were tested on eight new lacZ variants, and their experimentally determined mRNA half-lives all supported the model. We thus suggest that translation-rate-mediated differences in the spacing between ribosomes in this early coding region is a parameter that determines the mRNAs functional half-life. We present a model that is in accordance with many earlier observations and that allows a prediction of the functional half-life of a given mRNA sequence.
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Insulin and GH signaling in human skeletal muscle in vivo following exogenous GH exposure: impact of an oral glucose load.
PLoS ONE
PUBLISHED: 01-03-2011
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GH induces acute insulin resistance in skeletal muscle in vivo, which in rodent models has been attributed to crosstalk between GH and insulin signaling pathways. Our objective was to characterize time course changes in signaling pathways for GH and insulin in human skeletal muscle in vivo following GH exposure in the presence and absence of an oral glucose load.
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On surface-initiated atom transfer radical polymerization using diazonium chemistry to introduce the initiator layer.
Langmuir
PUBLISHED: 12-21-2010
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This work features the controllability of surface-initiated atom transfer radical polymerization (SI-ATRP) of methyl methacrylate, initiated by a multilayered 2-bromoisobutyryl moiety formed via diazonium chemistry. The thickness as a function of polymerization time has been studied by varying different parameters such as the bromine content of the initiator layer, polarity of reaction medium, ligand type (L), and the ratio of activator (Cu(I)) to deactivator (Cu(II)) in order to ascertain the controllability of the SI-ATRP process. The variation of thickness versus surface concentration of bromine shows a gradual transition from mushroom to brush-type conformation of the surface anchored chains in both polar and nonpolar reaction medium. Interestingly, it is revealed that very thick polymer brushes, on the order of 1 ?m, can be obtained at high bromine content of the initiator layer in toluene. The initial polymerization rate and the overall final thickness are higher in the case of nonpolar solvent (toluene) compared to polar medium (acetonitrile or N,N-dimethylformamide). The ligand affects the initial rate of polymerization, which correlates with the redox potentials of the pertinent Cu(II)/Cu(I) complexes (L = Me(6)TREN, PMDETA, and BIPY). It is also observed that the ability of polymer brushes to reinitiate depends on the initial thickness and the solvent used for generating it.
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Observations of variable inter-observer agreement for clinical evaluation of faecal consistency in grow-finishing pigs.
Prev. Vet. Med.
PUBLISHED: 11-23-2010
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Inter-observer agreement for assessment of faecal consistency in pigs was evaluated using a scoring system with 3 categories. In a pilot study, 3 observers performed an examination of faecal samples post-collection. The samples were obtained from pigs (12-13 weeks old) in 4 herds with a history of diarrhoea associated with Lawsonia intracellularis, Brachyspira spp. and/or Porcine Circovirus Type 2. Observer 1 examined all the faecal samples from the 4 herds. Observer 2 only examined the faecal samples from herds 1 and 2. Observer 3 only examined the faecal samples from herds 3 and 4. We observed a substantial agreement in faecal consistency scores between Observers 1 and 3 (kappa=0.64, 95% CI: 0.51-0.78). In contrast, only a fair agreement was observed between Observers 1 and 2 (kappa=0.24, 95% CI: 0.14-0.34). The variations in inter-observer agreement detected in the current study suggest that misclassification error can be a problem in studies assessing faecal consistency. Solutions may include developing a standardized system for scoring the consistency of pig faeces, calibration when more than one observer is involved in clinical studies and using a more objective measure of faecal consistency.
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Economy of operon formation: cotranscription minimizes shortfall in protein complexes.
MBio
PUBLISHED: 09-21-2010
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Genes of prokaryotes and Archaea are often organized in cotranscribed groups, or operons. In contrast, eukaryotic genes are generally transcribed independently. Here we show that there is a substantial economic gain for the cell to cotranscribe genes encoding protein complexes because it synchronizes the fluctuations, or noise, in the levels of the different components. This correlation substantially reduces the shortfall in production of the complex. This benefit is relatively large in small cells such as bacterial cells, in which there are few mRNAs and proteins per cell, and is diminished in larger cells such as eukaryotic cells.
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Regulation of CYP2C19 expression by estrogen receptor ?: implications for estrogen-dependent inhibition of drug metabolism.
Mol. Pharmacol.
PUBLISHED: 07-30-2010
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Cytochrome P4502C19 (CYP2C19) is an important drug-metabolizing enzyme involved in the biotransformation of, for example, proton pump inhibitors and antidepressants. Several in vivo studies have shown that the CYP2C19 activity is inhibited by oral contraceptives, which can cause important drug interactions. The underlying molecular mechanism has been suggested to be competitive inhibition. However, the results presented here indicate that estradiol derivatives down-regulate CYP2C19 expression via estrogen receptor (ER) ?, which interacts with the newly identified ER-binding half site [estrogen response element (ERE)] at the position -151/-147 in the CYP2C19 promoter. In gene reporter experiments in Huh-7 hepatoma cells, the activity of the luciferase construct carrying a 1.6-kb long CYP2C19 promoter fragment cotransfected with ER? was down-regulated upon treatment with 17?-estradiol (EE) or 17?-ethinylestradiol (ETE) at half-maximum concentrations of 10(-7) and 10(-8) M, respectively. Mutations introduced into the ERE half site -151/-147 significantly inhibited these ligand-dependent effects. Electrophoretic mobility shift assays and quantitative chromatin immunoprecipitation experiments revealed that estrogen receptor ? binds to this element. A significant suppression of CYP2C19 transcription by female sex steroids was confirmed by reverse transcription polymerase chain reaction after hormonal treatment of human hepatocytes. Inhibition experiments using a stable human embryonic kidney 293 CYP2C19 cell line revealed competitive inhibition at much higher concentrations of EE and ETE compared with those required for transcriptional inhibition. These results indicate that both EE and ETE inhibit CYP2C19 expression via an ER?-dependent regulatory pathway, thus providing a new insight into the molecular mechanism behind the inhibitory effect of oral contraceptives on CYP2C19 activity.
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Diagnostic performance of different fecal Lawsonia intracellularis-specific polymerase chain reaction assays as diagnostic tests for proliferative enteropathy in pigs: a review.
J. Vet. Diagn. Invest.
PUBLISHED: 07-13-2010
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Traditionally, diagnosis of Lawsonia intracellularis-associated proliferative enteropathy (PE) has depended on necropsy and histology. Since the establishment of the etiologic role of L. intracellularis, a number of specific polymerase chain reaction (PCR) assays have been developed for the detection of DNA in feces. The present article is a systematic review of peer-reviewed publications on the application of L. intracellularis-specific fecal PCR as an antemortem diagnostic test for histologic lesions of PE in pigs. Based on this information, a range of diagnostic sensitivities (36-100%) and specificities (50-100%) of the published tests was calculated. Validity and confidence limits of the estimates varied considerably. The positive and negative predictive values of 6 different PCR assays were calculated for PE prevalence of 15%, 30%, 45%, 60%, 75%, and 90%, using a histologic case definition of PE and based on the reported test sensitivities and specificities. The simulated predictive values suggested that applying the fecal PCR assay as a diagnostic test is more likely to overestimate than underestimate the number of pigs having histologic lesions of PE under field conditions.
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Decreased lipid intermediate levels and lipid oxidation rates despite normal lipolysis in patients with hypothyroidism.
Thyroid
PUBLISHED: 07-10-2010
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Hypothyroidism decreases energy expenditure and combustion of fuels, but the reported effects on lipid metabolism and insulin sensitivity are divergent and there is a lack of studies assessing rates of lipolysis and lipid oxidation. The present study was conducted to test the hypotheses that hypothyroidism decreases lipolysis, blood concentrations of free fatty acid, lipid oxidation, and insulin sensitivity.
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Intra- and inter-observer agreement when using a descriptive classification scale for clinical assessment of faecal consistency in growing pigs.
Prev. Vet. Med.
PUBLISHED: 07-05-2010
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The objective of the current study was to evaluate intra- and inter-observer agreement using a descriptive classification scale with four categories, descriptive text and pictures for assessment of consistency in faecal samples from pigs post weaning. The four consistency categories were score one=firm and shaped, score two=soft and shaped, score three=loose and score four=watery. Five observers from the same veterinary practice examined 100 faecal samples using the scale with four categories. Four of the observers examined the 100 faecal samples twice within the same day. Within observers the difference in proportions for the individual consistency categories between two examinations was on average 0.04 (range: 0-0.10). The mean intra-observer agreement was 0.82 (range: 0.72-0.91) with a mean kappa value of 0.76 (range: 0.61-0.88). For inter-observer agreement overall kappa was 0.64. For the 10 pair-wise comparisons the mean inter-observer agreement was 0.73 (range: 0.61-0.90) with a mean kappa value of 0.64 (range: 0.48-0.87). The difference in proportions for the individual consistency categories was on average 0.08 (range: 0-0.17). In conclusion, the agreement observed for the descriptive classification scale with four categories, descriptive text and pictures may be categorized as a substantial to almost perfect intra-observer agreement and a moderate to almost perfect inter-observer agreement. However, more objective measures than clinical scales may still be needed to improve intra- and inter-observer agreement in research studies.
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The nicotinic acetylcholine receptor and the Na,K-ATPase alpha2 isoform interact to regulate membrane electrogenesis in skeletal muscle.
J. Biol. Chem.
PUBLISHED: 07-01-2010
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The nicotinic acetylcholine receptor (nAChR) and the Na,K-ATPase functionally interact in skeletal muscle (Krivoi, I. I., Drabkina, T. M., Kravtsova, V. V., Vasiliev, A. N., Eaton, M. J., Skatchkov, S. N., and Mandel, F. (2006) Pflugers Arch. 452, 756-765; Krivoi, I., Vasiliev, A., Kravtsova, V., Dobretsov, M., and Mandel, F. (2003) Ann. N.Y. Acad. Sci. 986, 639-641). In this interaction, the specific binding of nanomolar concentrations of nicotinic agonists to the nAChR stimulates electrogenic transport by the Na,K-ATPase alpha2 isozyme, causing membrane hyperpolarization. This study examines the molecular nature and membrane localization of this interaction. Stimulation of Na,K-ATPase activity by the nAChR does not require ion flow through open nAChRs. It can be induced by nAChR desensitization alone, in the absence of nicotinic agonist, and saturates when the nAChR is fully desensitized. It is enhanced by noncompetitive blockers of the nAChR (proadifen, QX-222), which promote non-conducting or desensitized states; and retarded by tetracaine, which stabilizes the resting nAChR conformation. The interaction operates at the neuromuscular junction as well as on extrajunctional sarcolemma. The Na,K-ATPase alpha2 isozyme is enriched at the postsynaptic neuromuscular junction and co-localizes with nAChRs. The nAChR and Na,K-ATPase alpha subunits specifically coimmunoprecipitate with each other, phospholemman, and caveolin-3. In a purified membrane preparation from Torpedo californica enriched in nAChRs and the Na,K-ATPase, a ouabain-induced conformational change of the Na,K-ATPase enhances a conformational transition of the nAChR to a desensitized state. These results suggest a mechanism by which the nAChR in a desensitized state with high apparent affinity for agonist interacts with the Na,K-ATPase to stimulate active transport. The interaction utilizes a membrane-delimited complex involving protein-protein interactions, either directly or through additional protein partners. This interaction is expected to enhance neuromuscular transmission and muscle excitation.
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Accelerated 3D catheter visualization from triplanar MR projection images.
Magn Reson Med
PUBLISHED: 06-24-2010
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One major obstacle for MR-guided catheterizations is long acquisition times associated with visualizing interventional devices. Therefore, most techniques presented hitherto rely on single-plane imaging to visualize the catheter. Recently, accelerated three-dimensional (3D) imaging based on compressed sensing has been proposed to reduce acquisition times. However, frame rates with this technique remain low, and the 3D reconstruction problem yields a considerable computational load. In X-ray angiography, it is well understood that the shape of interventional devices can be derived in 3D space from a limited number of projection images. In this work, this fact is exploited to develop a method for 3D visualization of active catheters from multiplanar two-dimensional (2D) projection MR images. This is favorable to 3D MRI as the overall number of acquired profiles, and consequently the acquisition time, is reduced. To further reduce measurement times, compressed sensing is employed. Furthermore, a novel single-channel catheter design is presented that combines a solenoidal tip coil in series with a single-loop antenna, enabling simultaneous tip tracking and shape visualization. The tracked tip and catheter properties provide constraints for compressed sensing reconstruction and subsequent 2D/3D curve fitting. The feasibility of the method is demonstrated in phantoms and in an in vivo pig experiment.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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