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| 2. |
- Lidell, Martin, 1970, et al.
(författare)
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Evidence for two types of brown adipose tissue in humans
- 2013
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 19:5, s. 631-634
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Tidskriftsartikel (refereegranskat)abstract
- The previously observed supraclavicular depot of brown adipose tissue (BAT) in adult humans was
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| 3. |
- Eckerström, Carl, et al.
(författare)
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Small baseline volume of left hippocampus is associated with subsequent conversion of MCI into dementia. The Göteborg MCI study.
- 2008
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Ingår i: Journal of the Neurological Sciences. - : Elsevier BV. - 0022-510X .- 1878-5883. ; 272:1-2, s. 48-59
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Tidskriftsartikel (refereegranskat)abstract
- Background: Earlier studies have reported that hippocampal atrophy can to some extent predict which patients with mild cognitive impairment (MCI) will subsequently convert to dementia, and that converters have an enhanced rate of hippocampal volume loss. Objective: To further validate the hypothesis that hippocampal atrophy predicts conversion from MCI to dementia, to relate baseline hippocampal volume to different forms of dementia, and to investigate the role of hippocampal side differences and rate of volume loss over time. Patients: The subjects (N = 68) include patients with MCI at baseline and progression to dementia at the two-year follow-up (N = 21), stable MCI patients (N = 21), and controls (N = 26). Among the progressing patients, 13 were diagnosed as having AD. Methods: The Göteborg MCI study is a clinically based longitudinal study with biannual clinical assessments. Hippocampal volumetry was performed manually on the MRI investigations at baseline and at the two-year follow-up. Results: Hippocampal volumetry could predict conversion to dementia in both the AD and the non-AD subgroup of converters. Left hippocampal volume in particular discriminated between converting and stable MCI. Cut off points for individual discrimination were shown to be potentially useful. The converting MCI group had a significantly higher rate of hippocampal volume loss as compared to the stable MCI group. Conclusions: In MCI patients, hippocampal volumetry at baseline gives prognostic information about possible development of AD and non-AD dementia. Contrary to earlier studies, we found that left hippocampal volume has the best predictive power. Reliable predictions appear to be possible in many individual cases.
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| 4. |
- Korsgren, Magnus, et al.
(författare)
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Clinical efficacy and pharmacokinetic profiles of intranasal and oral cetirizine in a repeated allergen challenge model of allergic rhinitis.
- 2007
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Ingår i: Annals of Allergy, Asthma & Immunology. - 1081-1206. ; 98:4, s. 316-321
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Tidskriftsartikel (refereegranskat)abstract
- Background: Intranasal and oral antihistamines are effective in treating allergic rhinitis. Studies comparing these routes of administration of an antihistamine regarding efficacy and pharmacokinetic profile are lacking. Objective: To compare topical and oral routes of administration of cetirizine regarding efficacy, plasma exudation, and systemic drug levels in a repeated allergen challenge model of allergic rhinitis. Methods: Oral cetirizine dihydrochloride, 10 mg once daily, and topical cetirizine dinitrate in a dose corresponding to 4.4 mg of the dihydrochloride salt twice daily were given to grass pollen-sensitive individuals for 12 days in a double-blind, placebo-controlled, crossover design. Timothy grass pollen allergen challenges were given once daily for 7 days using a nasal spray device. Nasal symptoms and peak inspiratory flow were recorded in the morning, 10 minutes after allergen challenge, and in the evening. The pharmacokinetics of the treatments was monitored in 8 patients. The remaining 28 patients were challenged topically with histamine 12 and 24 hours after the final topical and oral cetirizine doses, respectively. Nasal lavage levels of alpha(2)-macroglobulin were determined to evaluate histamine-induced mucosal plasma exudation. Results: During the last 3 days of the repeated allergen challenge model, chronic symptoms were established. Both treatments reduced symptoms 10 minutes after allergen challenge (P < .001 vs placebo). Neither treatment reduced morning and evening symptoms or nasal peak inspiratory flow. Topical, but not oral, cetirizine reduced histamine-induced plasma exudation (P < .01 vs placebo) when systemic drug levels were similar in the 2 treatment regimens. Conclusions: Topical and oral cetirizine reduced acute nasal symptoms produced by allergen challenges in patients with established chronic symptoms. There were also antihistaminic effects of topical cetirizine not related to systemic drug levels.
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| 5. |
- Linge, Jennifer, et al.
(författare)
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Sub-phenotyping Metabolic Disorders Using Body Composition : An Individualized, Nonparametric Approach Utilizing Large Data Sets
- 2019
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Ingår i: Obesity. - : John Wiley & Sons. - 1930-7381 .- 1930-739X. ; 27:7, s. 1190-1199
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study performed individual-centric, data-driven calculations of propensity for coronary heart disease (CHD) and type 2 diabetes (T2D), utilizing magnetic resonance imaging-acquired body composition measurements, for sub-phenotyping of obesity and nonalcoholic fatty liver disease (NAFLD).Methods: A total of 10,019 participants from the UK Biobank imaging substudy were included and analyzed for visceral and abdominal subcutaneous adipose tissue, muscle fat infiltration, and liver fat. An adaption of the k-nearest neighbors algorithm was applied to the imaging variable space to calculate individualized CHD and T2D propensity and explore metabolic sub-phenotyping within obesity and NAFLD.Results: The ranges of CHD and T2D propensity for the whole cohort were 1.3% to 58.0% and 0.6% to 42.0%, respectively. The diagnostic performance, area under the receiver operating characteristic curve (95% CI), using disease propensities for CHD and T2D detection was 0.75 (0.73-0.77) and 0.79 (0.77-0.81). Exploring individualized disease propensity, CHD phenotypes, T2D phenotypes, comorbid phenotypes, and metabolically healthy phenotypes were found within obesity and NAFLD.Conclusions: The adaptive k-nearest neighbors algorithm allowed an individual-centric assessment of each individual’s metabolic phenotype moving beyond discrete categorizations of body composition. Within obesity and NAFLD, this may help in identifying which comorbidities a patient may develop and conse- quently enable optimization of treatment.
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| 6. |
- Tejani, Sanaa, et al.
(författare)
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Cardiometabolic Health Outcomes Associated With Discordant Visceral and Liver Fat Phenotypes: Insights From the Dallas Heart Study and UK Biobank
- 2022
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Ingår i: Mayo Clinic proceedings. - New York, United States : Elsevier. - 0025-6196 .- 1942-5546. ; 97:2, s. 225-237
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the cardiometabolic outcomes associated with discordant visceral adipose tissue (VAT) and liver fat (LF) phenotypes in 2 cohorts.Patients and Methods: Participants in the Dallas Heart Study underwent baseline imaging from January 1, 2000, through December 31, 2002, and were followed for incident cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) through 2013. Associations between VAT-LF groups (low-low, high-low, low-high, and high-high) and outcomes were assessed using multivariable- adjusted regression and were replicated in the independent UK Biobank.Results: The Dallas Heart Study included 2064 participants (mean SD age, 449 years; 54% female; 47% black). High VATehigh LF and high VATelow LF were associated with prevalent atheroscle- rosis, whereas low VATehigh LF was not. Of 1731 participants without CVD/T2DM, 128 (7.4%) developed CVD and 95 (5.5%) T2DM over a median of 12 years. High VATehigh LF and high VATelow LF were associated with increased risk of CVD (hazard ratios [HRs], 2.0 [95% CI, 1.3 to 3.2] and 2.4 [95% CI, 1.4 to 4.1], respectively) and T2DM (odds ratios [ORs], 7.8 [95% CI, 3.8 to 15.8] and 3.3 [95% CI, 1.4 to 7.8], respectively), whereas low VATehigh LF was associated with T2DM (OR, 2.7 [95% CI, 1.1 to 6.7]). In the UK Biobank (N1⁄422,354; April 2014-May 2020), only high VATelow LF remained associated with CVD after multivariable adjustment for age and body mass index (HR, 1.5 [95% CI, 1.2 to 1.9]).Conclusion: Although VAT and LF are each associated with cardiometabolic risk, these observations demonstrate the importance of separating their cardiometabolic implications when there is presence or absence of either or both in an individual.
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| 7. |
- Romu, Thobias, et al.
(författare)
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A randomized trial of cold-exposure on energy expenditure and supraclavicular brown adipose tissue volume in humans
- 2016
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Ingår i: Metabolism-Clinical and Experimental. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 65:6, s. 926-934
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To study if repeated cold-exposure increases metabolic rate and/or brown adipose tissue (BAT) volume in humans when compared with avoiding to freeze. Design. Randomized, open, parallel-group trial. Methods. Healthy non-selected participants were randomized to achieve cold-exposure 1 hour/day, or to avoid any sense of feeling cold, for 6 weeks. Metabolic rate (MR) was measured by indirect calorimetry before and after acute cold-exposure with cold vests and ingestion of cold water. The BAT volumes in the supraclavicular region were measured with magnetic resonance imaging (MRI). Results. Twenty-eight participants were recruited, 12 were allocated to controls and 16 to cold-exposure. Two participants in the cold group dropped out and one was excluded. Both the non-stimulated and the cold-stimulated MR were lowered within the group randomized to avoid cold (MR at room temperature from 1841 +/- 199 kCal/24 h to 1795 +/- 213 kCal/24 h, p = 0.047 cold-activated MR from 1900 +/- 150 kCal/24 h to 1793 +/- 215 kCal/24 h, p = 0.028). There was a trend towards increased MR at room temperature following the intervention in the cold-group (p = 0.052). The difference between MR changes by the interventions between groups was statistically significant (p = 0.008 at room temperature, p = 0.032 after cold-activation). In an on-treatment analysis after exclusion of two participants that reported >= 8 days without cold-exposure, supraclavicular BAT volume had increased in the cold-exposure group (from 0.0175 +/- 0.015 1 to 0.0216 +/- 0.014 1, p = 0.049). Conclusions. We found evidence for plasticity in metabolic rate by avoiding to freeze compared with cold-exposure in a randomized setting in non-selected humans.
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| 8. |
- Romu, Thobias, et al.
(författare)
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Characterization of Brown Adipose Tissue by Water-Fat Separated Magnetic Resonance Imaging
- 2015
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807 .- 1522-2586. ; 42:6, s. 1639-1645
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Tidskriftsartikel (refereegranskat)abstract
- Background: To evaluate the possibility of quantifying brown adipose tissue (BAT) volume and fat concentration with a high resolution, long echo time, dual-echo Dixon imaging protocol. Methods: A 0.42 mm isotropic resolution water-fat separated MRI protocol was implemented by using the second opposite-phase echo and third in-phase echo. Fat images were calibrated with regard to the intensity of nearby white adipose tissue (WAT) to form relative fat content (RFC) images. To evaluate the ability to measure BAT volume and RFC contrast dynamics, rats were divided into two groups that were kept at 48 or 22 degrees C for 5 days. The rats were then scanned in a 70 cm bore 3.0 Tesla MRI scanner and a human dual energy CT. Interscapular, paraaortal, and perirenal BAT (i/pa/pr-BAT) depots as well as WAT and muscle were segmented in the MRI and CT images. Biopsies were collected from the identified BAT depots. Results: The biopsies confirmed that the three depots identified with the RFC images consisted of BAT. There was a significant linear correlation (P< 0.001) between the measured RFC and the Hounsfield units from DECT. Significantly lower iBAT RFC (P=0.0064) and significantly larger iBAT and prBAT volumes (P=0.0017) were observed in the cold stimulated rats. Conclusion: The calibrated Dixon images with RFC scaling can depict BAT and be used to measure differences in volume, and fat concentration, induced by cold stimulation. The high correlation between RFC and HU suggests that the fat concentration is the main RFC image contrast mechanism.
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| 9. |
- Borga, Magnus, 1965-, et al.
(författare)
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MRI-Based Body Composition Analysis
- 2022. - 1
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Ingår i: Basic Protocols in Foods and Nutrition. - New York, NY, United States : Springer Nature. - 9781071623442 ; , s. 307-334
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Bokkapitel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) is considered being state-of-the-art technology for body composition analysis. Compared to other indirect techniques such as scales, calipers, bioimpedance, and dual-energy X-ray absorptiometry (DXA), MRI offers direct and precise measurements of the volumes of different tissue compartments and also enables quantification of diffuse fat infiltration in organs. Here, we describe a protocol for acquiring of fat–water-separated MRI data and the image postprocessing required for the quantification of several body composition biomarkers relevant for metabolic research. This protocol has successfully been used in several clinical studies and also in the large UK Biobank population study.
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| 10. |
- Cros, Olivier, et al.
(författare)
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Micro-channels in the mastoid anatomy. Indications of a separate blood supply of the air cell system mucosa by micro-CT scanning
- 2013
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Ingår i: Hearing Research. - : Elsevier. - 0378-5955 .- 1878-5891. ; 301, s. 60-65
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Tidskriftsartikel (refereegranskat)abstract
- The mastoid air cell system has traditionally been considered to have a passive role in gas exchange and pressure regulation of the middle ear possibly with some acoustic function. However, more evidence has focused on the mucosa of the mastoid, which may play a more active role in regulation of middle ear pressure.In this study we have applied micro-CT scanning on a series of three human temporal bones. This approach greatly enhances the resolution (40–60 μm), so that we have discovered anatomical details, which has not been reported earlier. Thus, qualitative analysis using volume rendering has demonstrated notable micro-channels connecting the surface of the compact bone directly to the mastoid air cells as well as forming a network of connections between the air cells. Quantitative analysis on 2D slices was employed to determine the average diameter of these micro-channels (158 μm; range = 40–440 μm) as well as their density at a localized area (average = 75 cm−2; range = 64–97 cm−2).These channels are hypothesized to contain a separate vascular supply for the mastoid mucosa. However, future studies of the histological structure of the micro-channels are warranted to confirm the hypothesis. Studies on the mastoid mucosa and its blood supply may improve our knowledge of its physiological properties, which may have important implications for our understanding of the pressure regulation of the middle ear.
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