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Search Results: 1 - 10 of 2605 matches for " Per Magne Ueland "
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Homocystein og livsstil. Resultater fra Homocysteinunders kelsen i Hordaland 1992-1993
Ottar Nyg?rd,Helga Refsum,Per Magne Ueland,Aage Tverdal
Norsk Epidemiologi , 2009,
Abstract: SAMMENDRAG Total homocystein (tHcy) er etablert som risikofaktor for hjerte- og karsykdom. Vi har studert determinanter av plasma tHcy i et utvalg av den voksne norske befolkning basert p unders kelse utf rt av Statens helseunders kelser i samarbeid med Universitetet i Bergen i 1992-1993. Data ble innhentet ved klinisk unders kelse, utfylling av tre sp rreskjema og ved blodtester. I alt 18 043 personer i alderen 40-67 r m tte til unders kelse og fikk m lt plasma tHcy. Plasma folat, plasma kobalamin og 677C →T mutasjonen i genet for metylentetrahydrofolatreduktase (MTHFR) er bestemt i et underutvalg p 329 personer og p personer med sv rt h ye tHcy verdier ( ≥ 40 μmol/L). Resultatene fra Homocysteinunders kelsen i Hordaland har vist at kj nn, alder, folatinntak, r ykevaner og kaffeforbruk er de sterkeste determinanter for plasma tHcy niv , mens kobalamininntak, fysisk aktivitet, blodtrykk og kolesterolniv er mindre sterke determinanter. Bruk av multivitaminer eller B-vitaminer er forbundet med spesielt lave tHcy niv er. Personer med tHcy ≥ 40 μmol/L er karakterisert ved h y forekomst (73%) av homozygositet for 67
Serial Plasma Choline Measurements after Cardiac Arrest in Patients Undergoing Mild Therapeutic Hypothermia: A Prospective Observational Pilot Trial
Christian Storm, Oliver Danne, Per Magne Ueland, Christoph Leithner, Dietrich Hasper, Tim Schroeder
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076720
Abstract: Objective Choline is related to phospholipid metabolism and is a marker for global ischaemia with a small reference range in healthy volunteers. The aim of our study was to characterize the early kinetics of plasma free choline in patients after cardiac arrest. Additionally, we investigated the potential of plasma free choline to predict neurological outcome. Methods Twenty patients admitted to our medical intensive care unit were included in this prospective, observational trial. All patients were enrolled between May 2010 and May 2011. They received post cardiac arrest treatment including mild therapeutic hypothermia which was initiated with a combination of cold fluid and a feedback surface cooling device according to current guidelines. Sixteen blood samples per patient were analysed for plasma free choline levels within the first week after resuscitation. Choline was detected by liquid chromatography-tandem mass spectrometry. Results Most patients showed elevated choline levels on admission (median 14.8 μmol/L; interquartile range; IQR 9.9-20.1) which subsequently decreased. 48 hours after cardiac arrest choline levels in all patients reached subnormal levels at a median of 4.0 μmol/L (IQR 3-4.9; p = 0.001). Subsequently, choline levels normalized within seven days. There was no significant difference in choline levels when groups were analyzed in relation to neurological outcome. Conclusions Our data indicate a choline deficiency in the early postresucitation phase. This could potentially result in impaired cell membrane recovery. The detailed characterization of the early choline time course may aid in planning of choline supplementation trials. In a limited number of patients, choline was not promising as a biomarker for outcome prediction.
Metabolic Profiling in Maturity-Onset Diabetes of the Young (MODY) and Young Onset Type 2 Diabetes Fails to Detect Robust Urinary Biomarkers
Anna L. Gloyn, Johan H. Faber, Daniel Malmodin, Gaya Thanabalasingham, Francis Lam, Per Magne Ueland, Mark I. McCarthy, Katharine R. Owen, Dorrit Baunsgaard
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040962
Abstract: It is important to identify patients with Maturity-onset diabetes of the young (MODY) as a molecular diagnosis determines both treatment and prognosis. Genetic testing is currently expensive and many patients are therefore not assessed and are misclassified as having either type 1 or type 2 diabetes. Biomarkers could facilitate the prioritisation of patients for genetic testing. We hypothesised that patients with different underlying genetic aetiologies for their diabetes could have distinct metabolic profiles which may uncover novel biomarkers. The aim of this study was to perform metabolic profiling in urine from patients with MODY due to mutations in the genes encoding glucokinase (GCK) or hepatocyte nuclear factor 1 alpha (HNF1A), type 2 diabetes (T2D) and normoglycaemic control subjects. Urinary metabolic profiling by Nuclear Magnetic Resonance (NMR) and ultra performance liquid chromatography hyphenated to Q-TOF mass spectrometry (UPLC-MS) was performed in a Discovery set of subjects with HNF1A-MODY (n = 14), GCK-MODY (n = 17), T2D (n = 14) and normoglycaemic controls (n = 34). Data were used to build a valid partial least squares discriminate analysis (PLS-DA) model where HNF1A-MODY subjects could be separated from the other diabetes subtypes. No single metabolite contributed significantly to the separation of the patient groups. However, betaine, valine, glycine and glucose were elevated in the urine of HNF1A-MODY subjects compared to the other subgroups. Direct measurements of urinary amino acids and betaine in an extended dataset did not support differences between patients groups. Elevated urinary glucose in HNF1A-MODY is consistent with the previously reported low renal threshold for glucose in this genetic subtype. In conclusion, we report the first metabolic profiling study in monogenic diabetes and show that, despite the distinct biochemical pathways affected, there are unlikely to be robust urinary biomarkers which distinguish monogenic subtypes from T2D. Our results have implications for studies investigating metabolic profiles in complex traits including T2D.
Bioinformatic and Genetic Association Analysis of MicroRNA Target Sites in One-Carbon Metabolism Genes
Nicole Stone, Faith Pangilinan, Anne M. Molloy, Barry Shane, John M. Scott, Per Magne Ueland, James L. Mills, Peader N. Kirke, Praveen Sethupathy, Lawrence C. Brody
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021851
Abstract: One-carbon metabolism (OCM) is linked to DNA synthesis and methylation, amino acid metabolism and cell proliferation. OCM dysfunction has been associated with increased risk for various diseases, including cancer and neural tube defects. MicroRNAs (miRNAs) are ~22 nt RNA regulators that have been implicated in a wide array of basic cellular processes, such as differentiation and metabolism. Accordingly, mis-regulation of miRNA expression and/or activity can underlie complex disease etiology. We examined the possibility of OCM regulation by miRNAs. Using computational miRNA target prediction methods and Monte-Carlo based statistical analyses, we identified two candidate miRNA “master regulators” (miR-22 and miR-125) and one candidate pair of “master co-regulators” (miR-344-5p/484 and miR-488) that may influence the expression of a significant number of genes involved in OCM. Interestingly, miR-22 and miR-125 are significantly up-regulated in cells grown under low-folate conditions. In a complementary analysis, we identified 15 single nucleotide polymorphisms (SNPs) that are located within predicted miRNA target sites in OCM genes. We genotyped these 15 SNPs in a population of healthy individuals (age 18–28, n = 2,506) that was previously phenotyped for various serum metabolites related to OCM. Prior to correction for multiple testing, we detected significant associations between TCblR rs9426 and methylmalonic acid (p = 0.045), total homocysteine levels (tHcy) (p = 0.033), serum B12 (p < 0.0001), holo transcobalamin (p < 0.0001) and total transcobalamin (p < 0.0001); and between MTHFR rs1537514 and red blood cell folate (p < 0.0001). However, upon further genetic analysis, we determined that in each case, a linked missense SNP is the more likely causative variant. Nonetheless, our Monte-Carlo based in silico simulations suggest that miRNAs could play an important role in the regulation of OCM.
Smoking and Body Fat Mass in Relation to Bone Mineral Density and Hip Fracture: The Hordaland Health Study
Jannike ?yen, Clara Gram Gjesdal, Ottar Kjell Nyg?rd, Stein Atle Lie, Haakon E. Meyer, Ellen Margrete Apalset, Per Magne Ueland, Eva Ringdal Pedersen, ?ivind Midttun, Stein Emil Vollset, Grethe S. Tell
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092882
Abstract: Lower bone mineral density (BMD) in smokers may be attributable to lower body weight or fat mass, rather than to a direct effect of smoking. We analyzed the effects of smoking exposure, assessed by plasma cotinine, and body fat on BMD and the risk of subsequent hip fracture. In the community-based Hordaland Health Study (HUSK), 3003 participants 46–49 years and 2091 subjects 71–74 years were included. Cotinine was measured in plasma and information on health behaviors was obtained from self-administered questionnaires. BMD and total body soft tissue composition were measured by dual X-ray absorptiometry. Information on hip fracture was obtained from computerized records containing discharge diagnoses for hospitalizations between baseline examinations 1997–2000 through December 31st, 2009. In the whole cohort, moderate and heavy smokers had stronger positive associations between fat mass and BMD compared to never smokers (differences in regression coefficient (95% CI) per % change in fat mass = 1.38 (0.24, 2.52) and 1.29 (0.17, 2.4), respectively). In moderate and heavy smokers there was a nonlinear association between BMD and fat mass with a stronger positive association at low compared to high levels of fat mass (Davies segmented test, p<0.001). In elderly women and men, heavy smokers had an increased risk of hip fracture compared to never smokers (hazard ratio = 3.31, 95% CI: 2.05, 5.35; p<0.001). In heavy smokers there was a tendency of a lower risk of hip fracture with higher percentage of fat mass. The deleterious effect of smoking on bone health is stronger in lean smokers than in smokers with high fat mass.
Omega-3 Status and the Relationship between Plasma Asymmetric Dimethylarginine and Risk of Myocardial Infarction in Patients with Suspected Coronary Artery Disease
Heidi Borgeraas,Elin Strand,Eva Ringdal Pedersen,Jutta Dierkes,Per Magne Ueland,Reinhard Seifert,Eirik Rebnord Wilberg,Pavol Bohov,Rolf K. Berge,Dennis W. T. Nilsen,Ottar Nyg?rd
Cardiology Research and Practice , 2012, DOI: 10.1155/2012/201742
Abstract: Background. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase. A previous rat study revealed an ADMA lowering effect following treatment with omega-3 polyunsaturated fatty acids (n-3 PUFAs). We sought to examine if an association between plasma ADMA and risk of acute myocardial infarction (AMI) was modified by serum n-3 PUFA status. Methods. The cohort included 1364 patients who underwent coronary angiography for suspected coronary artery disease in 2000-2001. Fatal and nonfatal AMI events were registered until December 31, 2006. Risk associations with AMI were estimated across ADMA quartiles (linear trend) and the upper decile. Results. No association between concentration of any n-3 PUFA and ADMA was observed. Only ADMA levels in upper decile were significantly associated with AMI with a multivariate adjusted hazard ratio (HR) (95% confidence interval) versus the rest of the population of 2.11 (1.34, 3.32). The association was strengthened among patients with below median levels of α-linolenic acid (ALA) (HR 3.12 (1.64, 5.93)), but was only influenced by longer chain n-3 PUFA after additional adjustments for HbA1c, estimated glomerular filtration rate, and hypercholesterolemia. Conclusions. The association of ADMA with risk of AMI is influenced by serum n-3 PUFA and particularly ALA. 1. Introduction An early and critical event in the pathogenesis of cardiovascular disease (CVD) is endothelial (vasodilator) dysfunction. Normal endothelial function depends on adequate levels of nitric oxide (NO), which acts as a vasodilator, inhibits the excessive proliferation of vascular smooth muscle cells [1], enhances endothelial cell survival and proliferation [2], and suppresses the adhesion of platelets and inflammatory cells to the vessel wall [3]. NO is synthesized from the amino acid L-arginine by a family of NO synthase enzymes (NOS). Asymmetric dimethylarginine (ADMA) acts as an inhibitor of NOS and thus decreases the synthesis and availability of NO. A high plasma level of ADMA is regarded as an independent predictor of CVD and is also associated with end stage renal disease [4]. Altered activity of the ADMA metabolizing enzymes, dimethylarginine dimethylaminohydrolase I and II (DDAH-I and DDAH-II), has been suggested as a possible cause for plasma ADMA accumulation. DDAH activity is directly downregulated by reactive oxygen species (ROS) generated by high glucose levels [5], oxidized LDL cholesterol (oxLDL), and the cytokine, tumor necrosis factor α (TNF-α) [6]. Additionally, the expression of endothelial cell protein
LQG Control Design for Balancing an Inverted Pendulum Mobile Robot  [PDF]
Ragnar Eide, Per Magne Egelid, Alexander Stams?, Hamid Reza Karimi
Intelligent Control and Automation (ICA) , 2011, DOI: 10.4236/ica.2011.22019
Abstract: The objective of this paper is to design linear quadratic controllers for a system with an inverted pendulum on a mobile robot. To this goal, it has to be determined which control strategy delivers better performance with respect to pendulum’s angle and the robot’s position. The inverted pendulum represents a challenging control problem, since it continually moves toward an uncontrolled state. Simulation study has been done in MATLAB Simulink environment shows that both LQR and LQG are capable to control this system successfully. The result shows, however, that LQR produced better response compared to a LQG strategy.
More Series related to the Euler Series
Odd Magne Ogreid,Per Osland
Physics , 1999,
Abstract: We present results for infinite series appearing in Feynman diagram calculations, many of which are similar to the Euler series. These include both one-, two- and three-dimensional series. All these series can be expressed in terms of zeta(2) and zeta(3).
Some infinite series related to Feynman diagrams
Odd Magne Ogreid,Per Osland
Physics , 2000,
Abstract: Results are presented for some infinite series appearing in Feynman diagram calculations, many of which are similar to the Euler series. These include both one-, two- and three-dimensional series. The sums of these series can be evaluated with the help of various integral representations for hypergeometric functions, and expressed in terms of $\zeta(2)$, $\zeta(3)$, the Catalan constant $G$ and ${\rm Cl}_2(\pi/3)$ where ${\rm Cl}_2(\theta)$ is Clausen's function.
Summing one- and two-dimensional series related to the Euler series
Odd Magne Ogreid,Per Osland
Mathematics , 1998,
Abstract: We present results for some infinite series appearing in Feynman diagram calculations, many of which are similar to the Euler series. These include both one-dimensional and two-dimensional series. Most of these series can be expressed in terms of zeta(2), zeta(3), the Catalan constant G and Cl{2}(pi/3) where Cl{2}(theta) is Clausen's function.
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