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- Kerkhof, H. J. M., et al.
(författare)
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Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium
- 2011
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 19:3, s. 254-264
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes. Methods: Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. We investigated whether different OA definitions result in different association results by creating various hip OA definitions in one large population based cohort (the Rotterdam Study I (RSI)) and testing those for association with gender, age and body mass index using one-way ANOVA. For ROA, we standardized the hip-, knee- and hand ROA definitions and calculated prevalence's of ROA before and after standardization in nine cohort studies. This procedure could only be performed in cohort studies and standardization of SOA definitions was not feasible at this moment. Results: In this consortium, all studies with SOA phenotypes (knee, hip and hand) used a different definition and/or assessment of OA status. For knee-, hip- and hand ROA five, four and seven different definitions were used, respectively. Different hip ROA definitions do lead to different association results. For example, we showed in the RSI that hip OA defined as "at least definite joint space narrowing (JSN) and one definite osteophyte" was not associated with gender (P=0.22), but defined as "at least one definite osteophyte" was significantly associated with gender (P=3 x 10(-9)). Therefore, a standardization process was undertaken for ROA definitions. Before standardization a wide range of ROA prevalence's was observed in the nine cohorts studied. After standardization the range in prevalence of knee- and hip ROA was small. Conclusion: Phenotype definitions influence the prevalence of OA and association with clinical variables. ROA phenotypes within the TREAT-OA consortium were standardized to reduce heterogeneity and improve power in future genetics studies. (C) 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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| 2. |
- Goedecke, Julia H., et al.
(författare)
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Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women
- 2015
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 58:11, s. 2647-2652
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis There is evidence to suggest that ectopic fat deposition in liver and skeletal muscle may differ between black and white women resulting in organ-specific differences in insulin sensitivity. Accordingly, the aim of the study was to examine ethnic differences in hepatic and peripheral insulin sensitivity, and the association with hepatic and skeletal muscle lipid content, and skeletal muscle gene expression. Methods In a cross-sectional study including 30 obese premenopausal black and white women, body composition (dual energy x-ray absorptiometry), liver fat and skeletal muscle (soleus and tibialis anterior) fat accumulation (proton-magnetic resonance spectroscopy), skeletal muscle gene expression, insulin sensitivity (two-step isotope labelled, hyperinsulinaemic-euglycaemic clamp with 10 mU m(-2) min(-1) and 40 mU m(-2) min(-1) insulin infusions), and serum adipokines were measured. Results We found that, although whole-body insulin sensitivity was not different, obese white women presented with lower hepatic insulin sensitivity than black women (% suppression of endogenous glucose production [% supp EGP], median [interquartile range (IQR)]: 17 [5-51] vs 56 [29-100] %, p = 0.002). While liver fat tended to be lower (p = 0.065) and skeletal muscle fat deposition tended to be higher (p = 0.074) in black compared with white women, associations with insulin sensitivity were only observed in black women (% supp EGP vs liver fat: r = -0.57, p < 0.05 and % supp EGP vs soleus fat: r = -0.56, p < 0.05). Conclusions/interpretation These findings may suggest that black women are more sensitive to the effects of ectopic lipid deposition than white women.
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| 3. |
- Hermannsson, P.G., et al.
(författare)
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Sodium enhanced oxidation: Absence of shallow interface traps after removal of sodium ions from the SiO2/4H-SiC interface
- 2013
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Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 740-742, s. 749-752
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Konferensbidrag (refereegranskat)abstract
- We investigate the strong passivation of shallow interface traps located near the SiC conduction band after enhanced oxidation of Si-face 4H-SiC in the presence of sodium. We find that removing the sodium ions present at the SiO2/SiC interface since oxidation by way of bias stress or annealing does not lead to a significant increase in the density of interface traps. The presence of sodium ions at the SiO2/SiC interface is therefore not responsible for the passivation of such interface traps in oxides formed by sodium enhanced oxidation.
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