Arthritis and rheumatism
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Arthritis and rheumatism · Apr 2004
Comparative StudyAssociation of squatting with increased prevalence of radiographic tibiofemoral knee osteoarthritis: the Beijing Osteoarthritis Study.
To examine the association between squatting, a common daily posture in China, and the prevalence of radiographic osteoarthritis (OA) in different knee compartments among Chinese subjects from Beijing, and to estimate how much of the difference in prevalence of knee OA between Chinese subjects in Beijing and white subjects in Framingham, Massachusetts is accounted for by the impact of squatting. ⋯ Prolonged squatting is a strong risk factor for tibiofemoral knee OA among elderly Chinese subjects in Beijing, and accounts for a substantial proportion of the difference in prevalence of tibiofemoral OA between Chinese subjects in Beijing and white subjects in Framingham.
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Arthritis and rheumatism · Apr 2004
Disruption of transforming growth factor beta signaling and profibrotic responses in normal skin fibroblasts by peroxisome proliferator-activated receptor gamma.
In fibroblasts, transforming growth factor beta (TGF beta) stimulates collagen synthesis and myofibroblast transdifferentiation through the Smad intracellular signal transduction pathway. TGF beta-mediated fibroblast activation is the hallmark of scleroderma and related fibrotic conditions, and disrupting the intracellular TGF beta/Smad signaling may provide a novel approach to controlling fibrosis. Because of its potential role in modulating inflammatory and fibrotic responses, we examined the expression of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) in normal skin fibroblasts and its effect on TGF beta-induced cellular responses. ⋯ By abrogating of TGF beta-induced stimulation of collagen gene expression, myofibroblast transdifferentiation, and Smad-dependent promoter activity in normal fibroblasts, PPAR gamma may play a physiologic role in the regulation of the profibrotic response. Furthermore, our results suggest that PPAR gamma activation by pharmacologic agonists may represent a novel approach to the control of fibrosis in scleroderma.
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Arthritis and rheumatism · Mar 2004
Lack of response to anakinra in rheumatoid arthritis following failure of tumor necrosis factor alpha blockade.
In patients with rheumatoid arthritis (RA) treated with tumor necrosis factor alpha (TNF alpha)- blocking therapy, there is heterogeneity of response. This raises the possibility that in certain circumstances, cytokines such as interleukin-1 (IL-1) may dominate the drive toward joint inflammation. This study was undertaken to investigate whether blocking the action of IL-1 with an IL-1 receptor antagonist (IL-1Ra) is efficacious in patients with disease that did not respond to TNF alpha blockade. ⋯ This study demonstrates that patients with disease that fails to respond to TNF alpha blockade also do not respond to IL-1Ra. These data do not provide evidence of a dominant role for IL-1 in patients who do not respond to TNF alpha blockade, but they do not exclude a role for other proinflammatory mediators.
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Arthritis and rheumatism · Mar 2004
The genetic contribution to muscle strength, knee pain, cartilage volume, bone size, and radiographic osteoarthritis: a sibpair study.
To estimate the heritability of muscle strength, knee pain, cartilage volume, bone size, and radiographic osteoarthritis (ROA), and to assess whether heritability of the knee structural components is independent of ROA. ⋯ With the exception of prevalent ROA, all knee modalities assessed had high heritability, most likely reflecting a strong genetic component. Cartilage volume, bone size, and muscle strength all have the potential to be studied in quantitative trait linkage analyses, but their exact relevance with regard to OA remains uncertain at this time.