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A model system for assessing physicochemical factors affecting calcium absorbability from the intestinal tract


, : A model system for assessing physicochemical factors affecting calcium absorbability from the intestinal tract. Journal of Bone and Mineral Research 4(1): 119-127

An in vitro model system was utilized to critically examine physicochemical factors that could play a role in determining the amount of potentially absorbable ionic calcium as well as soluble complexes in the proximal jejunum following ingestion of tricalcium dicitrate, calcium carbonate, or tricalcium diphosphate. The solubility of calcium salts (500 mg calcium each) was tested in 300 ml water containing varying amounts of hydrochloric acid (0, 0.72, 2.4, 7.26, and 24.2 mEq) intended to mimic achlorhydric to peak acid secretory states. Whereas 20% of calcium citrate dissolved in the absence of hydrochloric acid, a negligible amount of calcium carbonate and calcium phosphate underwent dissolution. In solutions containing 0.72-7.26 mEq hydrochloric acid, calcium citrate was more than twofold soluble than calcium carbonate, and calcium phosphate had intermediate solubility. At simulated peak acid secretion, all three salts were completely soluble, or nearly so. To simulate pancreatic bicarbonate secretion, the filtrates obtained from solubility studies were titrated to pH 5, 6, and 7 with sodium hydroxide. Reprecipitation of calcium citrate and calcium carbonate did not occur. However, substantial calcium phosphate reprecipitation took place especially at high pH and in filtrates derived from high hydrochloric acid content. In filtrates derived from reprecipitation experiments (at pH 6 and 7), anionic complexation of calcium was calculated in order to estimate the amount of ionic and complexed calcium. Considerable amount of calcium from dissolved calcium citrate was complexed (60-65%), principally as soluble CaCit-, whereas calcium complexation was negligible in the calcium carbonate and calcium phosphate systems.

US$19.90

PMID: 2718774

DOI: 10.1002/jbmr.5650040117


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Shang, X.; Chen, P.; Jia, T.; Feng, D.; Zhang, S.; Sun, Z.; Qiu, J., 2015: Upconversion luminescence mechanisms of Er(3+) ions under excitation of an 800 nm laser. The fundamental processes of upconversion (UC) emissions from trivalent lanthanide ions are essential for designing and improving the performance of UC materials. However, UC mechanisms involve multiple processes in one system because of the abund...

Y.J.; Tamura G.; Arima K., 1969: Milk clotting enzyme from microorganisms part 7 action of mucor renin and other proteases on hammarsten kappa casein and alpha casein plus beta casein agar gel plate. Nippon Nogeikagaku Kaishi 43(1): 60-66

Schlag, P.M.; Hünerbein, M.; Hohenberger, P., 1996: Surgical and multimodality approaches to liver metastases. Current Topics in Microbiology and Immunology 213: 241-255

Easton, N.R.; Gardner, J.H.; Stevens, J.R., 1947: A new synthesis and confirmation of the structure of amidone. Journal of the American Chemical Society 69(12): 2941-2941

Kananura, C.; Sander, T.; Rajan, S.; Preisig-Mueller, R.; Grzeschik, K.-Heinz; Daut, J.; Derst, C.; Steinlein, O., K., 2002: Tandem pore domain K+-channel TASK-3 (KCNK9) and idiopathic absence epilepsies. Recently, the gene coding for the tandem pore domain K(+)-channel TASK-3 (KCNK9) has been localized to the chromosomal region 8q24. Because mutations in ion channel genes have been recognized as an important factor in the etiology of abnormal neur...

Rhine S., 1971: Manual dimorphism a gripping factor in man. Southwestern And Rocky Mountain Division American Association Fo The Advancement Of Science, And Arizona Academy Of Scienceacts. Rocky Mountain Division American Association For The Advancement Of Science And The Fifteenth Annual Meeting Arizona Academy Of Sceince. April 21-24,: . 72

Rajamani, S.; El-Bizri, N.; Shryock, J.C.; Makielski, J.C.; Belardinelli, L., 2010: Use-dependent block of cardiac late Na(+) current by ranolazine. Ranolazine is an antianginal drug that inhibits the cardiac late Na+ current (INa). The selectivity of ranolazine to block late INa relative to peak INa at rapid heart rates has not been determined, but is potentially important to drug efficacy an...

Brown, M.T.; McBride, K.M.; Baniecki, M.Lynn.; Reich, N.C.; Marriott, G.; Mangel, W.F., 2002: Actin can act as a cofactor for a viral proteinase in the cleavage of the cytoskeleton. Cytoskeletal proteins are exploited by many viruses during infection. We report a novel finding that actin can act as a cofactor for the adenovirus proteinase (AVP) in the degradation of cytoskeletal proteins. Transfection studies in HeLa cells re...

Martin, S.A., 1989: Understanding competition for nutrients by ruminal bacteria: mechanisms and regulation of soluble sugar transport. Modes of action for degradation, transport and fermentation of feeds by rumen bacteria are reviewed.

Teng, J.; Duan, H.; Zheng, Y., 2016: Reference value for micronucleus frequency of peripheral blood lymphocytes in general Chinese population: a method of Monte Carlo simulation. To estimate the reference value for micronucleus frequency of peripheral blood lymphocytes in general Chinese population, and to guide the genotoxicity evaluation and risk analysis for populations exposed to environmental or occupational chemicals...