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Your search keyword '"van Leeuwen, J.P.T.M."' showing total 146 results
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146 results on '"van Leeuwen, J.P.T.M."'

9. Continuing medical education during pandemic waves of COVID-19: Consensus from medical faculties in Asia, Australia and Europe

Author

Wong, Carmen, primary, van den Broek, Walter, additional, Doody, Gillian, additional, Fischer, Martin, additional, Leech, Michelle, additional, De Ponti, Fabrizio, additional, Gerbes, Alexander, additional, Nishigori, Hiroshi, additional, Lee, Young Mee, additional, Frens, Maarten, additional, Kasuya, Hideki, additional, Bazzoli, Franco, additional, Hickel, Reinhard, additional, Lee, Hong Sik, additional, van Leeuwen, J.P.T.M, additional, Mitchell, Christina, additional, Kadomatsu, Kenji, additional, Atherton, John, additional, and Chan, Francis, additional

Published
2021
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11. Moderate cholecalciferol supplementation depresses intestinal calcium absorption in growing dogs

Author

Tryfonidou, M.A., Stevenhagen, J.J., van den Bemd, G.J.C.M., Oosterlaken-Dijksterhuis, M.A., DeLuca, H.F., Mol, J.A., van den Brom, J.A., van Leeuwen, J.P.T.M., and Hazewinkel, H.A.W.

Subjects
Cholecalciferols -- Physiological aspects, Calcium metabolism -- Research, Intestinal absorption -- Research, Dogs -- Physiological aspects, Food/cooking/nutrition
Abstract

Hormonal regulation of calcium (Ca) absorption was investigated in a cholecalciferol (vitamin D3)--supplemented group (hVitD) vs. a control group (cVitD) of growing Great Danes (100 vs. 12.5 [micro] g vitamin D3/kg diet). Although Ca intakes did not differ, fractional Ca absorption was significantly lower in the hVitD group than in the cVitD group. There were no differences in plasma concentrations of Ca, inorganic phospate, parathyroid hormone, growth hormone or insulin-like growth factor I between groups. Plasma 25-hydroxycholecalciferol [25(OH)[D.sub.3]] concentrations were maintained in the hVitD dogs at the same levels as in the cVitD dogs due to increased turnover of 25(OH)[D.sub.3] into 24,25-dihydroxycholecalciferol [24,25[(OH).sub.2][D.sub.3]] and 1,25-dihydroxycholecalciferol [1,25[(OH).sub.2][D.sub.3]]. In hVitD dogs, the greater plasma 24,25[(OH).sub.2][D.sub.3] concentration and the enhanced metabolic clearance rate (MCR) of 1,25[(OH).sub.2][D.sub.3] indicated upregulated 24-hydroxylase activity. The increased MCR of 1,25[(OH).sub.2][D.sub.3] decreased plasma 1,25[(OH).sub.2][D.sub.3] concentrations. In hVitD dogs, the greater production rate of 1,25[(OH).sub.2][D.sub.3] was consistent with the 12.9-fold greater renal 1 [alpha]-hydroxylase gene expression compared with cVitD dogs and compensated to a certain extent for the accelerated MCR of 1,25[(OH).sub.2][D.sub.3]. The moderately decreased plasma 1,25[(OH).sub.2][D.sub.3]concentration can only partially explain the decreased Ca absorption in the hVitD dogs. Intestinal vitamin D receptor concentrations did not differ between groups and did not account for the decreased Ca absorption. We suggest that 24,25[(OH).sub.2][D.sub3] may downregulate Ca absorption. KEY WORDS: * 1,25-dihydroxycholecalciferol * 24,25-dihydroxycholecalciferol * [sup.45]Ca balance * vitamin D receptor * dogs

Published
2002

14. Serum phosphate is associated with fracture risk: The Rotterdam Study and MrOS

Author

Campos-Obando, N, Koek, W.N.H., Hooker, E.R., van der Eerden, B.C.J., Pols, H.A., Hofman, A., van Leeuwen, J.P.T.M., Uitterlinden, A.G., Nielson, C.M., and Zillikens, MC

Subjects
Male, Femur Neck, Incidence, Fasting, Article, Phosphates, Fractures, Bone, Bone Density, Risk Factors, Humans, Female, Osteoporotic Fractures, Aged, Netherlands
Abstract

Extreme phosphate levels (P) have been associated with mineralization defects and increased fracture risk. Whether P within normal range is related to bone health in the general population is not well understood. To investigate the association of P with bone mineral density (BMD) and fracture risk, we assessed two population-based cohorts: the Dutch Rotterdam Study (RS-I, RS-II, RS-III; n = 6791) and the US Osteoporotic Fractures in Men (MrOS; n = 5425) study. The relationship of P with lumbar spine (LS) and femoral neck (FN) BMD was tested in all cohorts via linear models; fracture risk was tested in RS-I, RS-II, and MrOS through Cox models, after follow-up of 8.6, 6.6, and 10.9 years, respectively. Adjustments were made for age, body mass index, smoking, serum levels of calcium, potassium, 25-hydroxyvitamin D, estimated glomerular filtration rate (eGFR), FN-BMD, prevalent diabetes, and cardiovascular disease. Additional adjustments were made for phosphate intake, parathyroid hormone, and fibroblast growth factor 23 levels in MrOS. We further stratified by eGFR. Results were pooled through study-level meta-analyses. Hazard ratios (HR) and betas (β) (from meta-analyses) are expressed per 1 mg/dL P increase. P was positively associated with fracture risk in men and women from RS, and findings were replicated in MrOS (pooled HR all [95% CI]: 1.47 [1.31-1.65]). P was associated with fracture risk in subjects without chronic kidney disease (CKD): all (1.44 [1.26-1.63]) and in men with CKD (1.93 [1.42-2.62]). P was inversely related to LS-BMD in men (β: -0.06 [-0.11 to -0.02]) and not to FN-BMD in either sex. In summary, serum P was positively related to fracture risk independently from BMD and phosphate intake after adjustments for potential confounders. P and LS-BMD were negatively related in men. Our findings suggest that increased P levels even within normal range might be deleterious for bone health in the normal population. © 2017 American Society for Bone and Mineral Research.

Published
2017

16. EFFECT OF CALCIUM AND CHOLECALCIFEROL SUPPLEMENTATIONTATION ON SEVERAL PARAMETERS OF CALCIUM STATUS IN PLASMA AND URINE OF CAPTIVE ASIAN (ELEPHAS MAXIMUS) AND AFRICAN ELEPHANTS (LOXODONTA AFRICANA)

Author

Advances in Veterinary Medicine, Dep Gezondheidszorg Landbouwhuisdieren, van Sonsbeek, G.R., van der Kolk, J.H., van Leeuwen, J.P.T.M., Everts, H., Marais, J., Schaftenaar, W., Advances in Veterinary Medicine, Dep Gezondheidszorg Landbouwhuisdieren, van Sonsbeek, G.R., van der Kolk, J.H., van Leeuwen, J.P.T.M., Everts, H., Marais, J., and Schaftenaar, W.

Published
2013

23. Degree of glucose control is related to fracture risk in women with type 2 diabetes mellitus: The Rotterdam study

Author

Oei⁎, L., primary, Zillikens, M.C., additional, Dehghan, A., additional, Castano-Betancourt, M.C., additional, Estrada, K., additional, Stolk, L., additional, Oei, E.H.G., additional, van Meurs, J.B., additional, Hofman, A., additional, Sijbrands, E.J.G., additional, Janssen, J.A.M.J.L., additional, Witteman, J.C., additional, van Leeuwen, J.P.T.M., additional, Uitterlinden, A.G., additional, and Rivadeneira, F., additional

Published
2012
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48. 1α,25-dihydroxyvitamin D3 stimulates activin A production to fine-tune osteoblast-induced mineralization.

Author

Woeckel, V.J., van der Eerden, B.C.J., Schreuders‐Koedam, M., Eijken, M., and Van Leeuwen, J.P.T.M.

Subjects
VITAMIN D, ACTIVIN, OSTEOBLASTS, BONE density, BIOMINERALIZATION, CELL culture, FOLLISTATIN
Abstract

In healthy bones, mineralization has to be tightly controlled to avoid pathological phenotypes. In this study, we investigated interactions between 1α,25(OH)2D3 (1,25D3) and activin A in the regulation of osteoblast induced mineralization. In human osteoblast cultures, we demonstrated that besides stimulation of mineralization, 1,25D3 also induced activin A, a strong inhibitor of mineralization. Simultaneously, follistatin (FST), the natural antagonist of activin A, was down-regulated by1,25D3. This resulted in an increase in activin A activity during 1,25D3 treatment. We also showed that in 1,25D3-treated osteoblasts, mineralization can be further increased when activin A activity was abrogated by adding exogenous FST. This observation implies that, besides stimulation of mineralization, 1,25D3 also controls activin A-mediated inhibition of mineralization. Besides activin A, 1,25D3 also induces osteocalcin (BGLAP), another inhibitor of mineralization. Warfarin, which has been shown to inactivate osteocalcin, increased 1,25D3-induced mineralization. Interaction between these two systems became evident from the synergistic increase in BGLAP expression upon blocking activin activity in 1,25D3-treated cultures. In conclusion, we demonstrate that 1,25D3 stimulation of mineralization by human osteoblasts is suppressed by concomitant induction of inhibitors of mineralization. Mineralization induction by 1,25D3 may actually be controlled via interplay with activin A and osteocalcin. Finally, this complex regulation of mineralization substantiates the significance of tight control of mineralization to prevent excessive mineralization and consequently reduction in bone quality and strength. J. Cell. Physiol. 228: 2167-2174, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Published
2013
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