| 1. |
- Cheng, Sulin, et al.
(författare)
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Effects of calcium, dairy product, and vitamin D supplementation on bone mass accrual and body composition in 10-12-y-old girls: a 2-y randomized trial.
- 2005
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Ingår i: The American journal of clinical nutrition. - 0002-9165. ; 82:5
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Little is known about the relative effectiveness of calcium supplementation from food or pills with or without vitamin D supplementation for bone mass accrual during the rapid growth period. OBJECTIVE: The purpose was to examine the effects of both food-based and pill supplements of calcium and vitamin D on bone mass and body composition in girls aged 10-12 y. DESIGN: This placebo-controlled intervention trial randomly assigned 195 healthy girls at Tanner stage I-II, aged 10-12 y, with dietary calcium intakes <900 mg/d to 1 of 4 groups: calcium (1000 mg) + vitamin D3 (200 IU), calcium (1000 mg), cheese (1000 mg calcium), and placebo. Primary outcomes were bone indexes of the hip, spine, and whole body by dual-energy X-ray absorptiometry and of the radius and tibia by peripheral quantitative computed tomography. RESULTS: With the use of intention-to-treat or efficacy analysis, calcium supplementation with cheese resulted in a higher percentage change in cortical thickness of the tibia than did placebo, calcium, or calcium + vitamin D treatment (P = 0.01, 0.038, and 0.004, respectively) and in higher whole-body bone mineral density than did placebo treatment (P = 0.044) when compliance was >50%. With the use of a hierarchical linear model with random effects to control for growth velocity, these differences disappeared. CONCLUSIONS: Increasing calcium intake by consuming cheese appears to be more beneficial for cortical bone mass accrual than the consumption of tablets containing a similar amount of calcium. Diverse patterns of growth velocity may mask the efficacy of supplementation in a short-term trial of children transiting through puberty.
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| 2. |
- Eriksson, Anna-Lena, 1971, et al.
(författare)
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The COMT val158met polymorphism is associated with early pubertal development, height and cortical bone mass in girls.
- 2005
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Ingår i: Pediatric research. - 0031-3998. ; 58:1, s. 71-7
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens are involved in accretion of bone mass during puberty. Catechol-O-Methyltransferase (COMT) is involved in the degradation of estrogens. In this cross-sectional study we investigated associations between the COMT val158met polymorphism, which results in a 60-75% difference in enzyme activity between the val (high activity = H) and the met (low activity = L) variant, and skeletal phenotypes in 246 healthy pre/early pubertal girls. Girls with COMT(LL) were 5.4 cm taller than COMT(HH) girls. Dual x-ray absorptiometry showed higher values of bone mineral content (BMC), and larger areas of total body, femur and spine in COMT(LL). Cortical BMC, measured by peripheral quantitative computerized tomography in the tibia, was 9.8% higher in COMT(LL) compared with COMT(HH). This was due to a larger cortical cross sectional area while the cortical volumetric bone mineral density was not associated with COMT genotype. COMT(LL) girls had higher serum levels of free estradiol and insulin like growth factor. Regression models indicated that COMT genotype exerted effects on skeletal growth mainly via a regulation of free estradiol, resulting in an affected pubertal development (Tanner staging). We propose that the COMT(LL) genotype results in higher free estradiol levels and earlier pubertal development, leading to an increased skeletal growth in pre/early pubertal girls. Possible consequences for the adult skeleton however can be determined only after cessation of growth.
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| 3. |
- Lammi, Mikko, 1961-, et al.
(författare)
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Proteomic analysis of cartilage- and bone-associated samples.
- 2006
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Ingår i: Electrophoresis. - : John Wiley & Sons. - 0173-0835 .- 1522-2683. ; 27:13, s. 2687-2701
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Forskningsöversikt (refereegranskat)abstract
- The skeleton of the human body is built of cartilage and bone, which are tissues that contain extensive amounts of extracellular matrix (ECM). In bone, inorganic mineral hydroxyapatite forms 50-70% of the whole weight of the tissue. Although the organic matrix of bone consists of numerous proteins, 90% of it is composed of type I collagen. In cartilage, ECM forms a major fraction of the tissue, type II collagen and aggrecans being the most abundant macromolecules. It is obvious that the high content of ECM components causes analytical problems in the proteomic analysis of cartilage and bone, analogous to those in the analysis of low-abundance proteins present in serum. The massive contents of carbohydrates present in cartilage proteoglycans, and hydroxyapatite in bone, further complicate the situation. However, the development of proteomic tools makes them more and more tempting also for research of musculoskeletal tissues. Application of proteomic techniques to the research of chondrocytes, osteoblasts, osteocytes, and osteoclasts in cell cultures can immediately benefit from the present knowledge. Here we make an overview to previous proteomic research of cartilage- and bone-associated samples and evaluate the future prospects of applying proteomic techniques to investigate key events, such as cellular signal transduction, in cartilage- and bone-derived cells.
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| 4. |
- Leskinen, Jarkko, et al.
(författare)
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Genome-wide microarray analysis of MG-63 osteoblastic cells exposed to ultrasound.
- 2008
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Ingår i: Biorheology. - : IOS Press. - 0006-355X .- 1878-5034. ; 45:3-4, s. 345-354
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Tidskriftsartikel (refereegranskat)abstract
- It is well documented that low intensity pulsed ultrasound can be clinically used to accelerate bone fracture healing. Additionally, in vitro studies have shown that ultrasound can, for instance, increase mineralization, collagen production and alkaline phosphatase activity in osteoblasts. Despite the extensive research on the subject, the exact mechanism of ultrasound effect on bone cell gene regulation has not yet been deduced. In this study, we made an effort to reveal the features of genome-wide transcriptional response of osteoblast-type cells to ultrasound. MG-63 osteoblastic cell transcriptome was analyzed with whole genome microarray either 6 or 24 h after 30 min long exposure to 1.035 MHz pulsed ultrasound with three different acoustic pressures. Special attention was paid to the experimental design to minimize thermal effects and unwanted reflections of ultrasound. Microarray analysis suggested that ultrasound affects the genes involved with cellular membranes, and regulation of transcription as well. Several plasma membrane solute carriers were also regulated by ultrasound. It also changed the transcript level of several transcription factors belonging to the zinc finger proteins. However, ultrasound did not clearly promote genes involved with osteoblast differentiation.
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| 5. |
- Olkku, Anu, et al.
(författare)
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Ultrasound-induced activation of Wnt signaling in human MG-63 osteoblastic cells.
- 2010
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Ingår i: Bone. - : Elsevier BV. - 8756-3282 .- 1873-2763. ; 47:2, s. 320-330
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Tidskriftsartikel (refereegranskat)abstract
- The benefit from an ultrasound (US) exposure for fracture healing has been clearly shown. However, the molecular mechanisms behind this effect are not fully known. Recently, the canonical Wnt signaling pathway has been recognized as one of the essential regulators of osteoblastogenesis and bone mass, and thereby considered crucial for bone health. Mechanical loading and fluid shear stress have been reported to activate the canonical Wnt signaling pathway in bone cells, but previous reports on the effects of therapeutic US on Wnt signaling in general or in bone, in particular, have not been published yet. Therefore, activation of Wnt signaling pathway was assayed in human osteoblastic cells, and indeed, this pathway was found to be activated in MG-63 cells through the phosphoinositol 3-kinase/Akt (PI3K/Akt) and mTOR cascades following a single 10 min US exposure (2 W, 1.035 MHz). In addition to the reporter assay results, the Wnt pathway activation was also observed as nuclear localization of beta-catenin. Wnt activation showed also temperature dependence at elevated temperatures, and the expression of canonical Wnt ligands was induced under the thermal exposures. However, existence of a specific, non-thermal US component was evident as well, perhaps evidence of a potential dual action of therapeutic US on bone. Neither US nor heat exposures affected cell viability in our experiments. In summary, this is the first study to report that Wnt signaling cascade, important for osteoblast function and bone health, is one of the pathways activated by therapeutic US as well as by hyperthermia in human osteoblastic cells. Our results provide evidence for the potential molecular mechanisms behind the beneficial effects of US on fracture healing. Combinations of US, heat, and possible pharmacological treatment could provide useful flexibility for clinical cases in treating various bone disorders.
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