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- 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. |
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| 3. |
- Ivaska, Kaisa, et al.
(författare)
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Serial assessment of serum bone metabolism markers identifies women with the highest rate of bone loss and osteoporosis risk.
- 2008
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; May 6, s. 2622-2632
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Tidskriftsartikel (refereegranskat)abstract
- Context: One of the important challenges in the management of osteoporosis is to identify women who are at high risk of developing osteoporosis and fragility fractures. Objective: To evaluate if assessment of bone metabolism at multiple occasions can identify women with the highest risk for bone loss. Design: The Malmö OPRA study is an ongoing longitudinal study. Participants have been evaluated at baseline and after 1, 3 and 5 years. Setting: Population-based study. Participants: 1044 women, all 75 years old at baseline. Main outcome measures: Seven bone turnover markers were assessed at baseline, 1, 3 and 5 years (n=573). Five year change in areal bone mineral density (aBMD) was also determined. Results: Baseline markers correlated weakly to change in total body aBMD. The associations were more pronounced when the average of the baseline and 1-year measurements was used (standardized regression coefficients -0.12 to -0.23, p<0.01). Adding the 3-year and 5-year measurement further strengthened the correlation (regression coefficients up to -0.30 (p<0.001)). Women with constantly high turnover lost significantly more bone at total body (-2.6%) than women with intermediate (-1.6%) or low turnover (-0.2%, p for trend <0.001). They also had a greater decrease in hip BMD (-8.3%, -6.0% and -5.1%, respectively, p=0.010). Results were similar also in the subgroup of women with osteopenia. Conclusions: Our results suggest that serial assessment of bone turnover improves the identification of women with the highest rate of bone loss and osteoporosis risk.
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| 4. |
- Lehenkari, Petri, et al.
(författare)
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The effects of tamoxifen and toremifene on bone cells involve changes in plasma membrane ion conductance
- 2003
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 18:3, s. 473-481
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Tidskriftsartikel (refereegranskat)abstract
- Selective estrogen receptor modulators (SERMs), tamoxifen (Tam) and toremifene (Tor), are widely used in the treatment of breast cancer. In addition, they have been demonstrated to prevent estrogen deficiency-induced bone loss in postmenopausal women. These effects are thought to be caused by the interaction of the SERMs with the estrogen receptor, although SERMs have also been shown to conduct non-receptor-mediated effects such as rapid changes in membrane functions. We compared the effects of Tam, Tor, and 17β-estradiol (E2) on the viability of rat osteoclasts and osteoblasts. Both Tam and Tor were found to cause osteoclast apoptosis in in vitro cultures, which was reversed by E2. In addition, at higher concentration (10 μM), both SERMs had an estrogen receptor-independent effect, which involved interaction with the plasma membrane as demonstrated with UMR-108 osteosarcoma cells by Tam and Tor, but not E2. A leak of protons leading to changes in intracellular pH was shown both in medullary bone derived membrane vesicles and in intact cells. These effects were followed by a rapid loss of cell viability and subsequent cell lysis. Our results show that both Tam and Tor have an ionophoric effect on the plasma membranes of bone cells and that these SERMs differed in this ability: Tor induced rapid membrane depolarization only in the presence of high concentration of potassium. These non-receptor-mediated effects may be involved in therapeutic responses and explain some clinical side effects associated with the treatment of patients with these SERMs
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| 6. |
- Valta, Maija P, et al.
(författare)
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Regulation of Osteoblast Differentiation - A Novel Function for FGF-8.
- 2006
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 147:Jan 26, s. 2171-2182
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Tidskriftsartikel (refereegranskat)abstract
- Several members of the fibroblast growth factor (FGF) family have an important role in the development of skeletal tissues. FGF-8 is widely expressed in the developing skeleton, but its function there has remained unknown. We asked in this study whether FGF-8 could have a role in the differentiation of mesenchymal stem cells to an osteoblastic lineage. Addition of FGF-8 to mouse bone marrow cultures effectively increased initial cell proliferation as well as subsequent osteoblast-specific alkaline phosphatase production, bone nodule formation, and calcium accumulation if it was added to the cultures at an early stage of osteoblastic differentiation. Exogenous FGF-8 also stimulated the proliferation of MG63 osteosarcoma cells, which was blocked by a neutralizing antibody to FGF-8b. In addition, the heparin-binding growth factor fraction of Shionogi 115 (S115) mouse breast cancer cells, which express and secrete FGF-8 at a very high level, had an effect in bone marrow cultures similar to that of exogenous FGF-8. Interestingly, experimental nude mouse tumors of S115 cells present ectopic bone and cartilage formation as demonstrated by typical histology and expression of markers specific for cartilage (type II and IX collagen) and bone (osteocalcin). These results demonstrate that FGF-8 effectively predetermines bone marrow cells to differentiate to osteoblasts and increases bone formation in vitro. It is possible that FGF-8 also stimulates bone formation in vivo. The results suggest that FGF-8, which is expressed by a great proportion of malignant breast and prostate tumors, may, among other factors, also be involved in the formation of osteosclerotic bone metastases.
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