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- Uitterlinden, André G, et al.
(författare)
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The association between common vitamin D receptor gene variations and osteoporosis : a participant-level meta-analysis
- 2006
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Ingår i: Annals of Internal Medicine. - 0003-4819. ; 145:4, s. 255-264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Polymorphisms of the vitamin D receptor (VDR) gene have been implicated in the genetic regulation of bone mineral density (BMD). However, the clinical impact of these variants remains unclear.OBJECTIVE: To evaluate the relation between VDR polymorphisms, BMD, and fractures.DESIGN: Prospective multicenter large-scale association study.SETTING: The Genetic Markers for Osteoporosis consortium, involving 9 European research teams.PARTICIPANTS: 26,242 participants (18,405 women).MEASUREMENTS: Cdx2 promoter, FokI, BsmI, ApaI, and TaqI polymorphisms; BMD at the femoral neck and the lumbar spine by dual x-ray absorptiometry; and fractures.RESULTS: Comparisons of BMD at the lumbar spine and femoral neck showed nonsignificant differences less than 0.011 g/cm2 for any genotype with or without adjustments. A total of 6067 participants reported a history of fracture, and 2088 had vertebral fractures. For all VDR alleles, odds ratios for fractures were very close to 1.00 (range, 0.98 to 1.02) and collectively the 95% CIs ranged from 0.94 (lowest) to 1.07 (highest). For vertebral fractures, we observed a 9% (95% CI, 0% to 18%; P = 0.039) risk reduction for the Cdx2 A-allele (13% risk reduction in a dominant model).LIMITATIONS: The authors analyzed only selected VDR polymorphisms. Heterogeneity was detected in some analyses and may reflect some differences in collection of fracture data across cohorts. Not all fractures were related to osteoporosis.CONCLUSIONS: The FokI, BsmI, ApaI, and TaqI VDR polymorphisms are not associated with BMD or with fractures, but the Cdx2 polymorphism may be associated with risk for vertebral fractures.
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- Wilhelmsson, Ulrika, 1970, et al.
(författare)
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Absence of glial fibrillary acidic protein and vimentin prevents hypertrophy of astrocytic processes and improves post-traumatic regeneration
- 2004
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Ingår i: J Neurosci. - 1529-2401. ; 24:21, s. 5016-21
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Tidskriftsartikel (refereegranskat)abstract
- The regenerative capacity of the CNS is extremely limited. The reason for this is unclear, but glial cell involvement has been suspected, and oligodendrocytes have been implicated as inhibitors of neuroregeneration (Chen et al., 2000, GrandPre et al., 2000; Fournier et al., 2001). The role of astrocytes in this process was proposed but remains incompletely understood (Silver and Miller, 2004). Astrocyte activation (reactive gliosis) accompanies neurotrauma, stroke, neurodegenerative diseases, or tumors. Two prominent hallmarks of reactive gliosis are hypertrophy of astrocytic processes and upregulation of intermediate filaments. Using the entorhinal cortex lesion model in mice, we found that reactive astrocytes devoid of the intermediate filament proteins glial fibrillary acidic protein and vimentin (GFAP-/-Vim-/-), and consequently lacking intermediate filaments (Colucci-Guyon et al., 1994; Pekny et al., 1995; Eliasson et al., 1999), showed only a limited hypertrophy of cell processes. Instead, many processes were shorter and not straight, albeit the volume of neuropil reached by a single astrocyte was the same as in wild-type mice. This was accompanied by remarkable synaptic regeneration in the hippocampus. On a molecular level, GFAP-/-Vim-/- reactive astrocytes could not upregulate endothelin B receptors, suggesting that the upregulation is intermediate filament dependent. These findings show a novel role for intermediate filaments in astrocytes and implicate reactive astrocytes as potent inhibitors of neuroregeneration.
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