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30 results on '"Stefan, Norbert"'

1. Interscapular fat is associated with impaired glucose tolerance and insulin resistance independent of visceral fat mass

Author

Vosseler, Andreas, primary, Machann, Jürgen, additional, Fritsche, Louise, additional, Prystupa, Katsiaryna, additional, Kübler, Christian, additional, Häring, Hans‐Ulrich, additional, Birkenfeld, Andreas L., additional, Stefan, Norbert, additional, Peter, Andreas, additional, Fritsche, Andreas, additional, Wagner, Robert, additional, and Heni, Martin, additional

Published
2022
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2. Effects of resveratrol supplementation on liver fat content in overweight and insulin‐resistant subjects: A randomized, double‐blind, placebo‐controlled clinical trial

Author

Kantartzis, Konstantinos, primary, Fritsche, Louise, additional, Bombrich, Maria, additional, Machann, Jürgen, additional, Schick, Fritz, additional, Staiger, Harald, additional, Kunz, Iris, additional, Schoop, Rotraut, additional, Lehn‐Stefan, Angela, additional, Heni, Martin, additional, Peter, Andreas, additional, Fritsche, Andreas, additional, Häring, Hans‐Ulrich, additional, and Stefan, Norbert, additional

Published
2018
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3. Cover Image, Volume 30, Issue 9

Author

Machann, Jürgen, primary, Stefan, Norbert, additional, Wagner, Robert, additional, Bongers, Malte, additional, Schleicher, Erwin, additional, Fritsche, Andreas, additional, Häring, Hans-Ulrich, additional, Nikolaou, Konstantin, additional, and Schick, Fritz, additional

Published
2017
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5. Genetic determination of body fat distribution and the attributive influence on metabolism

Author

Fehlert, Ellen, primary, Wagner, Róbert, additional, Ketterer, Caroline, additional, Böhm, Anja, additional, Machann, Jürgen, additional, Fritsche, Louise, additional, Machicao, Fausto, additional, Schick, Fritz, additional, Staiger, Harald, additional, Stefan, Norbert, additional, Häring, Hans-Ulrich, additional, Fritsche, Andreas, additional, and Heni, Martin, additional

Published
2017
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6. Comparing methodological quality and consistency of international guidelines for the management of patients with chronic heart failure

Author

Michael, Kulig, Erika, Schulte, Schulte, Erika, Stefan, Willich, and Willich Stefan, Norbert

Subjects
Heart Failure, medicine.medical_specialty, Quality Assurance, Health Care, business.industry, media_common.quotation_subject, Management of heart failure, Alternative medicine, Disease Management, Guideline, Scientific evidence, Europe, Consistency (negotiation), Scale (social sciences), Family medicine, Chronic Disease, North America, Practice Guidelines as Topic, medicine, Humans, Quality (business), Cardiology and Cardiovascular Medicine, business, National Guideline Clearinghouse, New Zealand, media_common
Abstract

Background: Guidelines (GLs) for the management of heart failure (HF) are of great importance in order to define and disseminate therapeutic recommendations based on scientific evidence. The aim was to analyse and to compare the methodological quality of HF GLs as well as to evaluate the consistency of therapeutic recommendations. Methods: Eleven international GLs for the management of chronic HF were identified by search of the internet, electronic databases and references of published literature. Their methodological quality was assessed by two different appraisal instruments: (1) according to the US National Guideline Clearinghouse (NGC) on a scale from 0 to 17 points, (2) according to the German Guideline Clearinghouse (Agency for Quality in Medicine, AQUMED) on a scale from 0 to 44 points. Clinical criteria for assessment of the consistency of the recommendations included diagnostic testing, pharmacological and non-pharmacological treatment. Results: The quality scores of the GLs varied substantially with a range of 1.5–15.5 points (NGC) and 8–30 points (AQUMED). The greatest variation was found in the dimensions ‘development’ and ‘evidence’. Only 3 of the 11 GLs (≈30%) were rated as methodologically well prepared. The recommendations on diagnostic procedures and medical management were rather consistent among the different GLs. Conclusions: Published international GL recommendations on medical management of patients with chronic HF are broadly consistent. The methodological quality of the GLs, however, varies to a great extent. Improvement is needed in most methodological aspects, especially in the dimensions ‘evidence’ and ‘applicability’.

Published
2003

7. Relationships of body composition and liver fat content with insulin resistance in obesity‐matched adolescents and adults

Author

Linder, Katarzyna, primary, Springer, Fabian, additional, Machann, Jürgen, additional, Schick, Fritz, additional, Fritsche, Andreas, additional, Häring, Hans‐Ulrich, additional, Blumenstock, Gunnar, additional, Ranke, Michael B., additional, Stefan, Norbert, additional, Binder, Gerhard, additional, and Ehehalt, Stefan, additional

Published
2014
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8. Fraction of unsaturated fatty acids in visceral adipose tissue (VAT) is lower in subjects with high total VAT volume - a combined 1 H MRS and volumetric MRI study in male subjects

Author

Machann, Jürgen, primary, Stefan, Norbert, additional, Schabel, Christoph, additional, Schleicher, Erwin, additional, Fritsche, Andreas, additional, Würslin, Christian, additional, Häring, Hans-Ulrich, additional, Claussen, Claus D., additional, and Schick, Fritz, additional

Published
2012
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14. Pancreatic fat is negatively associated with insulin secretion in individuals with impaired fasting glucose and/or impaired glucose tolerance: a nuclear magnetic resonance study

Author

Heni, Martin, primary, Machann, Jürgen, additional, Staiger, Harald, additional, Schwenzer, Nina F., additional, Peter, Andreas, additional, Schick, Fritz, additional, Claussen, Claus D., additional, Stefan, Norbert, additional, Häring, Hans-Ulrich, additional, and Fritsche, Andreas, additional

Published
2010
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18. Psychological effects of prevention: do participants of a type 2 diabetes prevention program experience increased mental distress?

Author

Giel, Katrin E., primary, Enck, Paul, additional, Zipfel, Stephan, additional, Schrauth, Markus, additional, Bury, Anna, additional, Graf, Marjo, additional, Kümmerle, Sabine, additional, Guthoff, Martina, additional, Stefan, Norbert, additional, Häring, Hans-Ulrich, additional, and Fritsche, Andreas, additional

Published
2009
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28. Intra- and interindividual variability of fatty acid unsaturation in six different human adipose tissue compartments assessed by 1 H-MRS in vivo at 3 T.

Author

Machann J, Stefan N, Wagner R, Bongers M, Schleicher E, Fritsche A, Häring HU, Nikolaou K, and Schick F

Subjects
Adult, Aged, Female, Humans, Insulin Resistance, Liver metabolism, Male, Middle Aged, Organ Size, Reproducibility of Results, Young Adult, Adipose Tissue metabolism, Fatty Acids, Unsaturated metabolism, Proton Magnetic Resonance Spectroscopy methods
Abstract

It is generally accepted that the amount and distribution of adipose tissue (AT) in the human body play an important role in the pathogenesis of metabolic diseases. In addition, metabolic effects of released saturated fatty acids (FAs) in blood are known to be more critical than those of unsaturated FAs. However, little is known about the variability in unsaturation of FAs in various AT compartments. The aim of this prospective study was the assessment of mono- and polyunsaturated FAs in various AT compartments by localized 1 H-MRS in order to obtain insight into the intra- and interindividual variability. Associations of FA unsaturation with intrahepatic lipids (IHLs), insulin sensitivity and related AT volumes were analyzed. Fifty healthy Caucasians (36 male, 14 female) participated in this study. Spectroscopic examinations were performed in subcutaneous adipose tissue in the neck (SCAT neck ), abdominal deep subcutaneous adipose tissue (DSCAT), abdominal superficial subcutaneous adipose tissue (SSCAT), visceral adipose tissue (VAT), tibial bone marrow (BM) and subcutaneous adipose tissue of the lower leg (SCAT calf ) at 3 T. Unsaturated index (UI) was calculated by the ratio of olefinic and methyl resonances, polyunsaturated index (PUI) by the ratio of diallylic and methyl resonances. Volumes of AT compartments (by T 1 -weighted MRI) and IHL (single-voxel STEAM) were assessed at 1.5 T, insulin sensitivity by an oral glucose tolerance test. UI was highest for SCAT calf (0.622) and lowest for BM (0.527). Highest PUI was observed for SSCAT (0.108), lowest for BM (0.093). Significant intraindividual differences between UIs-but not PUIs-are present for most compartments. There is a non-significant trend for higher UI in males but otherwise no correlation to anthropometric data (age, BMI). A significant negative correlation between UI and AT volume was observed for VAT but for none of the other compartments. Neither UIs nor PUIs show a relation with IHL; insulin sensitivity is significantly correlated to UI in BM (p < 0.01). Unsaturation indices in several distinct AT compartments are location dependent. Our cohort showed only moderate gender-related differences, with a trend towards less unsaturated FAs (mainly PUI) in females. In BM, insulin resistant subjects are characterized by a higher UI compared with the insulin sensitive ones. Further studies in larger cohorts are necessary to gain further insight into unsaturation of AT., (Copyright © 2017 John Wiley & Sons, Ltd.)

Published
2017
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29. Fraction of unsaturated fatty acids in visceral adipose tissue (VAT) is lower in subjects with high total VAT volume - a combined 1 H MRS and volumetric MRI study in male subjects.

Author

Machann J, Stefan N, Schabel C, Schleicher E, Fritsche A, Würslin C, Häring HU, Claussen CD, and Schick F

Subjects
Adult, Animals, Humans, Imaging, Three-Dimensional, Male, Middle Aged, Protons, Reproducibility of Results, Sensitivity and Specificity, Young Adult, Adipose Tissue anatomy & histology, Adipose Tissue physiology, Fatty Acids, Unsaturated metabolism, Intra-Abdominal Fat anatomy & histology, Intra-Abdominal Fat physiology, Magnetic Resonance Imaging methods, Magnetic Resonance Spectroscopy methods
Abstract

Visceral adipose tissue (VAT) is thought to play an important role in the pathogenesis of obesity and insulin resistance. However, little is known about the composition of VAT with regard to the amount of mono- (MUFAs) and polyunsaturated fatty acids (PUFAs) in triglycerides. Volume-selective MRS was performed in addition to MRI for the quantification of VAT. Analysis comprised proton signals from the vinyl-H group (H-C=C-H), including protons from MUFA+PUFA, and diallylic-H, i.e. methylene-interrupted PUFAs. The methyl (-CH(3) ) resonance, which is the only peak with a defined number of protons/triglyceride (n=9), served as reference. Twenty male subjects participated in this prospective study and underwent MRS of VAT on a 3-T whole-body unit. Spectra were recorded by a single-voxel stimulated echo acquisition mode (STEAM) technique (TE/TM/TR=20/10/4000 ms; volume of interest between 20 × 25 × 20 and 30 × 30 × 20 mm(3); 48-80 acquisitions depending on the size of the volume of interest; bandwidth, 1200 Hz). Post-processing was performed by a Java-based magnetic resonance user interface (jMRUI; AMARES). The volume of VAT was quantified in a separate session on a 1.5-T imager a few days prior to the MRS session by T(1) -weighted imaging. The relative amount of VAT was calculated as a percentage of body weight (%VAT). Ratios of vinyl-H to -CH(3) and diallylic-H to -CH(3) were calculated. All spectra recorded from VAT were of high quality, enabling reliable quantification of the mentioned resonances. %VAT and vinyl-H/CH(3) varied over a broad range (2.8-8.3% and 0.45-0.64, respectively). A strong negative correlation between %VAT and vinyl-H/CH(3) was found (r= -0.92), whereas diallylic-H/CH(3) alone was clearly less well correlated with %VAT (r= -0.21). The composition of VAT shows strong interindividual variations. The greater the total amount of VAT, the less unsaturated the fatty acids. This is a preliminary result in mainly obese male subjects, and it remains to be determined whether this correlation holds for other cohorts of different age, gender and body mass index. Furthermore, changes in VAT composition during weight loss or different forms of diet have yet to be examined., (Copyright © 2012 John Wiley & Sons, Ltd.)

Published
2013
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30. Hepatic lipid accumulation in healthy subjects: a comparative study using spectral fat-selective MRI and volume-localized 1H-MR spectroscopy.

Author

Machann J, Thamer C, Schnoedt B, Stefan N, Haring HU, Claussen CD, Fritsche A, and Schick F

Subjects
Adult, Body Mass Index, Female, Humans, Linear Models, Longitudinal Studies, Male, Middle Aged, Reproducibility of Results, Fatty Liver diagnosis, Magnetic Resonance Imaging methods, Magnetic Resonance Spectroscopy methods
Abstract

Fat-selective MRI was applied to assess the amount and spatial distribution of hepatic lipids (HL) in healthy subjects. The results were compared with those obtained by localized 1H-MR spectroscopy (MRS). Ninety subjects (23-63 years old) underwent single-slice fat-selective MRI with spatial-spectral excitation and volume-localized spectroscopy at 1.5 T. HLs were analyzed in ventral and dorsal regions of interest (ROIs) of the liver in fat-selective images. Spectra were evaluated using the integral signal of methylene and methyl signals. The fat-selective images showed smooth and homogeneous distribution of HL over the entire cross section of the liver. There was, however, a marked interindividual variability in the amount of HL. MRS revealed a lipid signal fraction between 0.5% and 39.3%. The fat content in the ROIs in images correlated well with the spectroscopic results (r >or= 0.95). Both techniques provide sufficient sensitivity for a reliable and quantitative assessment of liver steatosis in subjects without liver disease. 1H-MRS has a higher sensitivity compared to MRI, especially for small amounts of HL, which may be of interest for metabolic interventions. Fat-selective images provide more spatial information about fat distribution, which makes this technique suitable for clinical imaging of patients with liver disease., ((c) 2006 Wiley-Liss, Inc.)

Published
2006
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