Effect of oral calcium carbonate on aortic calcification in apolipoprotein E-deficient (apoE-/-) mice with chronic renal failure.

BACKGROUND: In chronic kidney disease (CKD) patients, the intake of calcium-based phosphate binders is associated with a marked progression of coronary artery and aortic calcification, in contrast to patients receiving calcium-free phosphate binders. The aim of this study was to reexamine the role of calcium carbonate in vascular calcification and to analyse its effect on aortic calcification-related gene expression in chronic renal failure (CRF). METHODS: Mice deficient in apolipoprotein E underwent either sham operation or subtotal nephrectomy to create CRF. They were then randomly assigned to one of the three following groups: a control non-CRF group and a CRF group fed on standard diet, and a CRF group fed on calcium carbonate enriched diet, for a period of 8 weeks. Aortic atherosclerotic plaque and calcification were evaluated using quantitative morphologic image processing. Aortic gene and protein expression was examined using immunohistochemistry and Q-PCR methods. RESULTS: Calcium carbonate supplementation was effective in decreasing serum phosphorus but was associated with a higher serum calcium concentration. Compared with standard diet, calcium carbonate enriched diet unexpectedly induced a significant decrease of both plaque (p<0.05) and non-plaque-associated calcification surface (p<0.05) in CRF mice. It also increased osteopontin (OPN) protein expression in atherosclerotic lesion areas of aortic root. There was also a numerical increase in OPN and osteoprotegerin gene expression in total thoracic aorta but the difference did not reach the level of significance. Finally, calcium carbonate did not change the severity of atherosclerotic lesions. CONCLUSION: In this experimental model of CRF, calcium carbonate supplementation did not accelerate but instead decreased vascular calcification. If our observation can be extrapolated to humans, it appears to question the contention that calcium carbonate supplementation, at least when given in moderate amounts, necessarily enhances vascular calcification. It is also compatible with the hypothesis of a preponderant role of phosphorus over that of calcium in promoting vascular calcification in CRF.

Report on Special Investigation of Before and After School Services, For the Period July 1, 2000 through December 31, 2004

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Report on the Special Investigation of the City of Mt. Vernon Fire Department, For the Period January 1, 2003 through March 31, 2005

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Dubuque County, Auditor of State's Report on Reaudit, For the Period July 1, 2002 through June 30, 2003

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City of Silver City, Auditor of State's Report on Reaudit, For the Period July 1, 2002 through June 30, 2003

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Ames Community School District, Auditor of State's Report on Reaudit, For the Period July 1st, 2003 through June 30th, 2004

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Report on Special Investigation of the Rural Iowa Waste Management Association for the Period July 1st, 1999 through October 15th, 2004

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Rural Iowa Waste Management Association Independent Auditor's Reports Finanical Statement and Required Supplementary Information Schedule of Findings for the period ending June 30, 2004.

Rural Iowa Waste Management Association Independent Auditor's Reports, Financial Statement, Required Supplementary Information and Schedule of Findings for the Period Ending June 30, 2004.

City of Perry, Auditor of State's Report on Reaudit for the Period July 1, 2002 through June 30, 2003

City of Perry, Auditor of State's Report on Reaudit for the Period July 1, 2002 through June 30, 2003

County Recorders Electronic Transaction Fees Under the Control of the State Treasurer and the Iowa County Recorders Association, Auditor of State's Report for the Period July 1, 2003 through September 30, 2005

County Recorders Electronic Transaction Fees Under the Control of the State Treasurer and the Iowa County Recorders Association, Auditor of State's Report for the Period July 1, 2003 through September 30, 2005

Report on Special Investigation of the Keokuk County Information Technology Department, For the Period October 14, 2002 through March 14, 2005

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Board of Regent Universities, A Review of Procurement Card Programs, For the Period July 1, 2001 through June 30, 2003

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Report on Special Investigation of the City of Valeria, For the Period January 1, 2004 through August 31, 2005

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Randomized observation periods for the compound Poisson risk model: Dividends

In the framework of the classical compound Poisson process in collective risk theory, we study a modification of the horizontal dividend barrier strategy by introducing random observation times at which dividends can be paid and ruin can be observed. This model contains both the continuous-time and the discrete-time risk model as a limit and represents a certain type of bridge between them which still enables the explicit calculation of moments of total discounted dividend payments until ruin. Numerical illustrations for several sets of parameters are given and the effect of random observation times on the performance of the dividend strategy is studied.