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Charles Y.c. Pak - One of the best experts on this subject based on the ideXlab platform.

  • animal protein and the risk of kidney stones a comparative metabolic study of animal protein sources
    The Journal of Urology, 2014
    Co-Authors: Chad R Tracy, Khashayar Sakhaee, Charles Y.c. Pak, John R Poindexter, Sara L Best, Aditya Bagrodia, Beverly Adamshuet, Naim M Maalouf, Margaret S Pearle
    Abstract:

    Purpose: We compared the effect of 3 animal protein sources on urinary stone risk.Materials and Methods: A total of 15 healthy subjects completed a 3-phase randomized, crossover metabolic study. During each 1-week phase subjects consumed a standard metabolic diet containing beef, chicken or fish. Serum chemistry and 24-hour urine samples collected at the end of each phase were compared using mixed model repeated measures analysis.Results: Serum and urinary uric acid were increased for each phase. Beef was associated with lower serum uric acid than chicken or fish (6.5 vs 7.0 and 7.3 mg/dl, respectively, each p <0.05). Fish was associated with higher urinary uric acid than beef or chicken (741 vs 638 and 641 mg per day, p = 0.003 and 0.04, respectively). No significant difference among phases was noted in urinary pH, sulfate, Calcium, Citrate, oxalate or sodium. Mean saturation index for Calcium oxalate was highest for beef (2.48), although the difference attained significance only compared to chicken (1.6...

  • superior Calcium bioavailability of effervescent potassium Calcium Citrate over tablet formulation of Calcium Citrate after roux en y gastric bypass
    Surgery for Obesity and Related Diseases, 2013
    Co-Authors: Khashayar Sakhaee, Charles Y.c. Pak
    Abstract:

    Abstract Background Calcium supplementation is commonly recommended for patients after Roux-en-Y gastric bypass to avert bone loss. To test the hypothesis that effervescent (liquid) potassium-Calcium-Citrate (PCC) might be more bioavailable than a tablet formulation of Calcium Citrate (Citracal Petite), the present study compared a single dose response of the 2 compounds. The present study was conducted at the University of Texas Southwestern Medical School at Dallas. Methods A total of 15 patients who had undergone Roux-en-Y gastric bypass were included in a 2-phase, crossover, randomized study comparing the single-dose bioavailability of PCC versus Citracal Petite. After following a restricted diet for 1 week, the participants ingested either a single dose of 400 mg elemental Calcium as PCC or Citracal Petite. Sequential serum and urine samples were collected for a 6-hour period after the dose and analyzed for Calcium, parathyroid hormone, and acid-base parameters. Results Compared with citracal petite, PCC significantly increased the serum Calcium concentrations at 2, 3, and 4 hours after the oral load. The peak to baseline variation and increment in serum Calcium (area under the curve) were significantly greater after PCC (P = .015 and P = .002, respectively). Concurrently, the baseline to nadir variation and decrement in serum parathyroid hormone (area over the curve) were significantly greater after PCC (P = .004 and P = .005, respectively). Moreover, compared with Citracal Petite, PCC caused a significantly greater increment in urinary Citrate (P Conclusion In patients who have undergone Roux-en-Y gastric bypass, PCC was superior to Citracal Petite in conferring bioavailable Calcium and suppressing parathyroid hormone secretion. PCC also provided an alkali load.

  • Biochemical control of bone loss and stone-forming propensity by potassium-Calcium Citrate after bariatric surgery
    Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery, 2011
    Co-Authors: Khashayar Sakhaee, Carolyn Griffith, Charles Y.c. Pak
    Abstract:

    Abstract Background Patients undergoing Roux-en-Y gastric bypass (RYGB) surgery are prone to developing bone loss and kidney stones. The goal of the present study was to test the hypothesis that an effervescent formulation of potassium Calcium Citrate (PCC) would avert metabolic complications by providing bioavailable Calcium and alkali. Methods A total of 24 patients with RYGB underwent a 2-phase crossover randomized trial comparing PCC and placebo. During the last 2 days of each 2-week phase, the serum and 24-hour urine samples were analyzed for Calcium and bone turnover markers, acid base status, and urinary stone risk factors. Results Compared with placebo, PCC marginally reduced the serum parathyroid hormone level and significantly decreased urinary deoxypyridinoline by 12% ( P P P P Conclusion In RYGB patients, PCC supplementation inhibited bone resorption by providing bioavailable Calcium, reduced the urinary saturation of uric acid, and increased the inhibitor activity against Calcium oxalate agglomeration by providing alkali that increased urinary pH and Citrate.

  • assessment by reflection ultrasound method of the effect of intermittent slow release sodium fluoride Calcium Citrate therapy on material strength of bone
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Joseph E Zerwekh, Khashayar Sakhaee, Peter P Antich, Jerome Gonzales, Frank A Gottschalk, Charles Y.c. Pak
    Abstract:

    It has been suggested that fluoride therapy, while increasing bone mass, produces bone with inferior mechanical properties. In the present report this hypothesis was tested using a novel reflection ultrasound technique. Transiliac crest bone biopsies were obtained from 16 patients with osteoporosis and vertebral compression fractures (12 women and 4 men, mean age 56 years) before and after approximately 2 years of intermittent slow-release sodium fluoride therapy (25 mg twice a day) combined with continuous Calcium Citrate supplementation. Samples were analyzed by a reflection ultrasound method, which analyzes ultrasound velocity with a sample site resolution of 200 microns and thus provides a measure of the mechanical property of single trabeculae (material). For the group, mean fractional change in velocity increased 6.1 +/- 2.3% (SEM) from a mean value of 3303 +/- 80 to 3484 +/- 55 m/s (p = 0.028). A total of 13 patients (81%) demonstrated higher velocities after treatment. Thus reflection ultrasound analysis of bone appears to provide a sensitive means of assessing changes in the material property of bone. Furthermore, these results suggest that the treatment regimen utilized in these patients improves strength of bone at the material or trabecular level largely independently of change in bone mass. The combination therapy also increased spinal (L2-L4) bone density for the group as assessed by dual-photon absorptiometry (5.3 +/- 2.0%). There was no significant correlation between the change in ultrasound velocity and bone density (r = 0.0026, p = 0.996).(ABSTRACT TRUNCATED AT 250 WORDS)

  • dose dependency of Calcium absorption a comparison of Calcium carbonate and Calcium Citrate
    Journal of Bone and Mineral Research, 2009
    Co-Authors: A Jean M D Harvey, Margaret M Zobitz, Charles Y.c. Pak
    Abstract:

    Calcium supplementation is recommended as a prophylaxis against bone loss. This study was performed to determine the dose dependency of Calcium absorption in an attempt to derive an optimum dose schedule. Using the well-described oral Calcium load technique, we measured the Calcium absorption from three different Calcium doses (0.5, 1.0, and 2.0 g) of both Calcium carbonate and Calcium Citrate administered to 21 normal subjects (4 men and 17 women, 22-60 years). Nine subjects underwent two additional loads with 0.2 g of elemental Calcium as Calcium carbonate and as Calcium Citrate. The intestinal Calcium absorption from Calcium carbonate and Calcium Citrate was estimated from the rise in urinary Calcium following oral ingestion of the respective Calcium salt. The increment in urinary Calcium post-load, reflective of intestinal Calcium absorption, rose rapidly from 0 to 0.5 g Calcium loads with only slight subsequent increases from the 0.5 g to 2.0 g Calcium doses. Thus, results indicate that 0.5 g of Calcium is the optimum dose of either Calcium salt. Moreover, the increment in urinary Calcium post-load was higher from Calcium Citrate than from Calcium carbonate at all four dosage levels. The increment in urinary Calcium (during the second 2 hr) following Calcium Citrate load (0.5 g Calcium) was 0.104 +/- 0.096 mg/dl glomerular filtrate (GF), which was higher than that of 0.091 +/- 0.068 mg/dl GF obtained from 2.0 g Calcium as Calcium carbonate. These results confirm the superior Calcium bioavailability from Calcium Citrate as compared with Calcium carbonate.(ABSTRACT TRUNCATED AT 250 WORDS)

Khashayar Sakhaee - One of the best experts on this subject based on the ideXlab platform.

  • animal protein and the risk of kidney stones a comparative metabolic study of animal protein sources
    The Journal of Urology, 2014
    Co-Authors: Chad R Tracy, Khashayar Sakhaee, Charles Y.c. Pak, John R Poindexter, Sara L Best, Aditya Bagrodia, Beverly Adamshuet, Naim M Maalouf, Margaret S Pearle
    Abstract:

    Purpose: We compared the effect of 3 animal protein sources on urinary stone risk.Materials and Methods: A total of 15 healthy subjects completed a 3-phase randomized, crossover metabolic study. During each 1-week phase subjects consumed a standard metabolic diet containing beef, chicken or fish. Serum chemistry and 24-hour urine samples collected at the end of each phase were compared using mixed model repeated measures analysis.Results: Serum and urinary uric acid were increased for each phase. Beef was associated with lower serum uric acid than chicken or fish (6.5 vs 7.0 and 7.3 mg/dl, respectively, each p <0.05). Fish was associated with higher urinary uric acid than beef or chicken (741 vs 638 and 641 mg per day, p = 0.003 and 0.04, respectively). No significant difference among phases was noted in urinary pH, sulfate, Calcium, Citrate, oxalate or sodium. Mean saturation index for Calcium oxalate was highest for beef (2.48), although the difference attained significance only compared to chicken (1.6...

  • superior Calcium bioavailability of effervescent potassium Calcium Citrate over tablet formulation of Calcium Citrate after roux en y gastric bypass
    Surgery for Obesity and Related Diseases, 2013
    Co-Authors: Khashayar Sakhaee, Charles Y.c. Pak
    Abstract:

    Abstract Background Calcium supplementation is commonly recommended for patients after Roux-en-Y gastric bypass to avert bone loss. To test the hypothesis that effervescent (liquid) potassium-Calcium-Citrate (PCC) might be more bioavailable than a tablet formulation of Calcium Citrate (Citracal Petite), the present study compared a single dose response of the 2 compounds. The present study was conducted at the University of Texas Southwestern Medical School at Dallas. Methods A total of 15 patients who had undergone Roux-en-Y gastric bypass were included in a 2-phase, crossover, randomized study comparing the single-dose bioavailability of PCC versus Citracal Petite. After following a restricted diet for 1 week, the participants ingested either a single dose of 400 mg elemental Calcium as PCC or Citracal Petite. Sequential serum and urine samples were collected for a 6-hour period after the dose and analyzed for Calcium, parathyroid hormone, and acid-base parameters. Results Compared with citracal petite, PCC significantly increased the serum Calcium concentrations at 2, 3, and 4 hours after the oral load. The peak to baseline variation and increment in serum Calcium (area under the curve) were significantly greater after PCC (P = .015 and P = .002, respectively). Concurrently, the baseline to nadir variation and decrement in serum parathyroid hormone (area over the curve) were significantly greater after PCC (P = .004 and P = .005, respectively). Moreover, compared with Citracal Petite, PCC caused a significantly greater increment in urinary Citrate (P Conclusion In patients who have undergone Roux-en-Y gastric bypass, PCC was superior to Citracal Petite in conferring bioavailable Calcium and suppressing parathyroid hormone secretion. PCC also provided an alkali load.

  • Biochemical control of bone loss and stone-forming propensity by potassium-Calcium Citrate after bariatric surgery
    Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery, 2011
    Co-Authors: Khashayar Sakhaee, Carolyn Griffith, Charles Y.c. Pak
    Abstract:

    Abstract Background Patients undergoing Roux-en-Y gastric bypass (RYGB) surgery are prone to developing bone loss and kidney stones. The goal of the present study was to test the hypothesis that an effervescent formulation of potassium Calcium Citrate (PCC) would avert metabolic complications by providing bioavailable Calcium and alkali. Methods A total of 24 patients with RYGB underwent a 2-phase crossover randomized trial comparing PCC and placebo. During the last 2 days of each 2-week phase, the serum and 24-hour urine samples were analyzed for Calcium and bone turnover markers, acid base status, and urinary stone risk factors. Results Compared with placebo, PCC marginally reduced the serum parathyroid hormone level and significantly decreased urinary deoxypyridinoline by 12% ( P P P P Conclusion In RYGB patients, PCC supplementation inhibited bone resorption by providing bioavailable Calcium, reduced the urinary saturation of uric acid, and increased the inhibitor activity against Calcium oxalate agglomeration by providing alkali that increased urinary pH and Citrate.

  • assessment by reflection ultrasound method of the effect of intermittent slow release sodium fluoride Calcium Citrate therapy on material strength of bone
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Joseph E Zerwekh, Khashayar Sakhaee, Peter P Antich, Jerome Gonzales, Frank A Gottschalk, Charles Y.c. Pak
    Abstract:

    It has been suggested that fluoride therapy, while increasing bone mass, produces bone with inferior mechanical properties. In the present report this hypothesis was tested using a novel reflection ultrasound technique. Transiliac crest bone biopsies were obtained from 16 patients with osteoporosis and vertebral compression fractures (12 women and 4 men, mean age 56 years) before and after approximately 2 years of intermittent slow-release sodium fluoride therapy (25 mg twice a day) combined with continuous Calcium Citrate supplementation. Samples were analyzed by a reflection ultrasound method, which analyzes ultrasound velocity with a sample site resolution of 200 microns and thus provides a measure of the mechanical property of single trabeculae (material). For the group, mean fractional change in velocity increased 6.1 +/- 2.3% (SEM) from a mean value of 3303 +/- 80 to 3484 +/- 55 m/s (p = 0.028). A total of 13 patients (81%) demonstrated higher velocities after treatment. Thus reflection ultrasound analysis of bone appears to provide a sensitive means of assessing changes in the material property of bone. Furthermore, these results suggest that the treatment regimen utilized in these patients improves strength of bone at the material or trabecular level largely independently of change in bone mass. The combination therapy also increased spinal (L2-L4) bone density for the group as assessed by dual-photon absorptiometry (5.3 +/- 2.0%). There was no significant correlation between the change in ultrasound velocity and bone density (r = 0.0026, p = 0.996).(ABSTRACT TRUNCATED AT 250 WORDS)

  • comparison of the absorption of Calcium carbonate and Calcium Citrate after roux en y gastric bypass
    Obesity Surgery, 2009
    Co-Authors: P Tondapu, Beverley Adamshuet, David A Provost, Thomas Sims, Craig G Chang, Khashayar Sakhaee
    Abstract:

    Introduction Roux-en-Y gastric bypass (RYGB) restricts food intake. Consequently, patients consume less Calcium. In addition, food no longer passes through the duodenum, the main site of Calcium absorption. Therefore, Calcium absorption is significantly impaired. The goal of this study is to compare two common Calcium supplements in gastric bypass patients.

Leif H Skibsted - One of the best experts on this subject based on the ideXlab platform.

  • temperature effects on spontaneous supersaturation of Calcium Citrate in presence of lactate
    International Dairy Journal, 2021
    Co-Authors: Xiaochen Liu, Jacob J K Kirkensgaard, Leif H Skibsted
    Abstract:

    Abstract Supersaturation of Calcium salts of low solubility is important for biomineralisation. The dynamics of solutions supersaturated in Calcium Citrate prepared by dissolving Calcium lactate and sodium Citrate in water, serving as a mineralisation model, were characterised electrochemically and by small-angle X-ray scattering. The process was divided into: (i) Citrate assisted dissolution of Calcium lactate with an enthalpy of activation of 115 kJ mol−1; (ii) a metastable homogeneous supersaturation phase, where Calcium ion activity continues to increase despite constant Calcium concentration; (iii) Calcium ion activity decreasing with an enthalpy of activation of 30 kJ mol−1 together with 3-dimensional crystallisation with an enthalpy of activation of 177 kJ mol−1. The differences in activation enthalpies lead to a higher degree of supersaturation at higher temperatures but longer lasting supersaturation at low temperature as was seen for critical supersaturation of up to a factor of 20 resulting in non-linear temperature effects for Calcium mobility.

  • hydrates of Calcium Citrate and their interconversion in relation to Calcium bioaccessibility
    Food Research International, 2021
    Co-Authors: Xiaochen Liu, Jacob J K Kirkensgaard, Leif H Skibsted
    Abstract:

    Abstract Calcium Citrate tetrahydrate (CCT) and hexahydrate (CCH) precipitates from aqueous solutions of CaCl2 and sodium Citrate above and below the transition temperature of 52 °C, respectively. The CCT, the dihydrate (CCD) and anhydrate (CCA) as obtained by a stepwise dehydration of solid CCH have enthalpy of dehydration of ΔH0CCH to CCT = 43.6, ΔH0CCT to CCD = 43.8, and ΔH0CCD to CCA = 88.1 kJ∙mol−1 as measured by DSC. WAXS measurements demonstrate a stepwise decrease in unit cell size upon dehydration, and a stronger binding of the two first water compared to additional. The increasing negative enthalpy of dissolution, as calculated from the temperature dependence of solubility (10–90 °C), +21 kJ∙mol−1 (CCH), –20 kJ∙mol−1 (CCT), –22 kJ∙mol−1 (CCD), and –40 kJ∙mol−1 (CCA) shows along the series of hydrates with increasing solubility, enthalpy–entropy compensation with an isoequilibrium temperature of 49 °C. Conversion of CCD and CCA in aqueous solutions yields the more soluble CCT, not the stable CCH in agreement with Ostwald’s stage law, increasing Calcium bioaccessibility under physiological conditions in intestines.

  • Calcium availability from whey mineral residues increased by hydrogen Citrate
    Food Research International, 2020
    Co-Authors: Andressa De Zawadzki, Leif H Skibsted
    Abstract:

    Insoluble mineral residues from whey processing dominated by hydroxyapatite and Calcium hydrogen phosphate were found to dissolve isothermally in aqueous sodium hydrogen Citrate. Dissolution occurred spontaneously and the resultant homogeneous solutions were found to be supersaturated solutions in both Calcium Citrate and Calcium hydrogen phosphate. Supersaturation was investigated by visual inspection combined with turbidity measurements and analyses of Calcium and phosphorous by ICP. The maximal supersaturation was found to be proportional to total hydrogen Citrate concentration. For 0.2 M hydrogen Citrate, maximum Calcium concentration was achieved in the first hours of dissolution resulting in the supersaturation of Calcium hydrogen phosphate with a factor of 10. Calcium Citrate rather than Calcium hydrogen phosphate precipitated from the supersaturated solutions and the time elapsing before precipitation began, increased with increasing concentrations of excess of hydrogen Citrate. This lag phase for precipitation ranged from several hours for 0.2 M hydrogen Citrate to more than a day for higher hydrogen Citrate concentrations, for which the solutions were saturated in Calcium hydrogen phosphate and became supersaturated only in Calcium Citrate due to the strong binding of Calcium by Citrate. The appearance and decay of supersaturation was kinetically studied in order to provide the background for future exploration of whey minerals in functional foods for improved Calcium nutrition.

  • combinations of isoCitrate and Citrate enhance Calcium salt solubility and supersaturation robustness
    International Dairy Journal, 2018
    Co-Authors: Andre C Garcia, Bente Danielsen, Hong Cheng, Ning Tang, Leif H Skibsted
    Abstract:

    Abstract Calcium isoCitrate tetrahydrate was characterised and found to be less soluble in water than Calcium Citrate tetrahydrate. The solubilities of both decrease with temperature, but increase with pressure. Calcium binds isoCitrate with a constant of Ka = (6.80 ± 0.05) × 103 (ΔH° = −22.1 ± 2.6 kJ mol−1; ΔS° = −6.7 ± 8.7 J mol−1 K−1). The solubility product is Ksp = (8.7 ± 0.08) × 10−17 (ΔH° = 30.1 ± 2.2 kJ mol−1; ΔS° = −206 ± 7 J mol−1 K−1). Calcium isoCitrate dissolves in aqueous sodium Citrate, spontaneously forming solutions supersaturated in Calcium Citrate by a factor of at least two for 0.50 mol L−1 sodium Citrate from which precipitation initiates after 20 h. Calcium Citrate dissolves under similar conditions in sodium isoCitrate forming supersaturated solutions in Calcium isoCitrate without precipitation for months. Slow crystallisation kinetics of Calcium isoCitrate explains the supersaturation robustness for combinations of Calcium Citrate and sodium isoCitrate inspiring for formulation of whey mineral products.

  • supersaturation of Calcium Citrate as a mechanism behind enhanced availability of Calcium phosphates by presence of Citrate
    Food Research International, 2018
    Co-Authors: Martina Vavrusova, Andre C Garcia, Leif H Skibsted
    Abstract:

    Abstract Dissolution of amorphous Calcium phosphate (ACP) in aqueous Citrate at varying pH has been studied with perspective of increasing availability of Calcium from sidestreams of whey protein, lactose and/or cheese production or on development of new functional foods. ACP formed as an initial precipitate in 0.10 mol L−1 equimolar aqueous Calcium chloride, sodium Citrate, and sodium hydrogenphosphate was used as model for mineral residues formed during milk processing. Upon acidification of the ACP suspension by hydrochloric acid decreasing pH from 6.5 to 4.5, the transformations of ACP occurred through an 8 h period of supersaturation prior to a slow precipitation of Calcium Citrate tetrahydrate. This robust supersaturation, which may explain increased availability of Calcium phosphates in presence of Citrate, presented a degree of supersaturation of 7.1 and was characterized by precipitation rates for 0.10 mol L−1 equimolar aqueous Calcium chloride, sodium hydrogenCitrate, and sodium hydrogenphosphate with pH 5.5, and for 0.10 mol L−1 equimolar aqueous Calcium chloride, sodium hydrogenCitrate, and sodium dihydrogenphosphate with pH 4.1, with a degree of supersaturation of 2.7. The crystallization processes were similar according to Avrami's model with a half-life for precipitation of approximately 5 h independent of the degree of supersaturation. Ion speciation based on measurement of pH, and total concentrations of Calcium, phosphate and Citrate, and of conductivity and Calcium ion activity during precipitation indicates a low driving force for precipitation with Calcium Citrate complex dominating at pH 5.5 and Calcium hydrogenCitrate complex dominating at pH 4.1. Calcium hydrogenCitrate is suggested to be the species involved in the crystal growth followed by solid state transformation to Calcium Citrate tetrahydrate.

John R Poindexter - One of the best experts on this subject based on the ideXlab platform.

  • animal protein and the risk of kidney stones a comparative metabolic study of animal protein sources
    The Journal of Urology, 2014
    Co-Authors: Chad R Tracy, Khashayar Sakhaee, Charles Y.c. Pak, John R Poindexter, Sara L Best, Aditya Bagrodia, Beverly Adamshuet, Naim M Maalouf, Margaret S Pearle
    Abstract:

    Purpose: We compared the effect of 3 animal protein sources on urinary stone risk.Materials and Methods: A total of 15 healthy subjects completed a 3-phase randomized, crossover metabolic study. During each 1-week phase subjects consumed a standard metabolic diet containing beef, chicken or fish. Serum chemistry and 24-hour urine samples collected at the end of each phase were compared using mixed model repeated measures analysis.Results: Serum and urinary uric acid were increased for each phase. Beef was associated with lower serum uric acid than chicken or fish (6.5 vs 7.0 and 7.3 mg/dl, respectively, each p <0.05). Fish was associated with higher urinary uric acid than beef or chicken (741 vs 638 and 641 mg per day, p = 0.003 and 0.04, respectively). No significant difference among phases was noted in urinary pH, sulfate, Calcium, Citrate, oxalate or sodium. Mean saturation index for Calcium oxalate was highest for beef (2.48), although the difference attained significance only compared to chicken (1.6...

  • a model system for assessing physicochemical factors affecting Calcium absorbability from the intestinal tract
    Journal of Bone and Mineral Research, 2009
    Co-Authors: Charles Y.c. Pak, John R Poindexter, Birdwell Finlayson
    Abstract:

    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.

  • stone forming risk of Calcium Citrate supplementation in healthy postmenopausal women
    The Journal of Urology, 2004
    Co-Authors: Khashayar Sakhaee, Carolyn Griffith, John R Poindexter, Charles Y.c. Pak
    Abstract:

    ABSTRACT Purpose: We evaluated the effect of Calcium Citrate supplementation alone or in combination with potassium Citrate on the stone forming propensity in healthy postmenopausal women. Materials and Methods: A total of 18 postmenopausal women without stones underwent a randomized trial of 4 phases comprised of 2 weeks of treatment with placebo, Calcium Citrate (400 mg Calcium twice daily), potassium Citrate (20 mEq twice daily), and Calcium Citrate and potassium Citrate (at same doses). During the last 2 days of each phase urine was collected in 24-hour pools for complete stone risk analysis. Results: Compared to placebo, Calcium Citrate increased urinary Calcium and Citrate but decreased urinary oxalate and phosphate. Urinary saturation of Calcium oxalate, brushite and undissociated uric acid did not change. Potassium Citrate decreased urinary Calcium, and increased urinary Citrate and pH. It decreased urinary saturation of Calcium oxalate and undissociated uric acid, and did not change the saturation of brushite. When Calcium Citrate was combined with potassium Citrate, urinary Calcium remained high, urinary Citrate increased even further and urinary oxalate remained reduced from the Calcium Citrate alone, thereby marginally decreasing the urinary saturation of Calcium oxalate. Urinary pH increased, decreasing urinary undissociated uric acid. The increase in pH increased the saturation of brushite despite the decrease in urinary phosphorus. Conclusions: Calcium Citrate supplementation does not increase the risk of stone formation in healthy postmenopausal women. The co-administered potassium Citrate may provide additional protection against formation of uric acid and Calcium oxalate stones.

  • slow release sodium fluoride in the management of postmenopausal osteoporosis a randomized controlled trial
    Annals of Internal Medicine, 1994
    Co-Authors: Charles Y.c. Pak, Khashayar Sakhaee, John R Poindexter, Veronica K Piziak, Roy D Peterson, Neil A Breslau, Peggy Boyd, Jean Herzog
    Abstract:

    OBJECTIVE To test whether intermittent treatment with slow-release sodium fluoride and continuous Calcium Citrate supplementation inhibits vertebral fractures without causing fluoride complications. DESIGN A placebo-controlled, randomized trial. SETTING Outpatient setting of specialty clinics in Dallas and Temple, Texas. INTERVENTIONS Slow-release sodium fluoride (25 mg twice daily) in repeated 14-month cycles (12 months on treatment followed by 2 months off treatment) compared with placebo. Both groups took Calcium Citrate (400 mg Calcium twice daily) continuously. PATIENTS 110 patients with postmenopausal osteoporosis were randomly assigned to two groups. In the slow-release sodium fluoride group, 48 of 54 patients completed more than 1 cycle of treatment (mean, 2.44 cycles/patient), whereas 51 of 56 patients in the placebo group completed at least 1 cycle (mean, 2.14 cycles/patient) in this interim analysis. MEASUREMENTS Vertebral fracture rate and lumbar bone mineral content. Vertebral fractures were quantified from yearly radiographs. Bone mass was determined annually by densitometry. RESULTS In the sodium fluoride group, the mean L2 to L4 bone mineral content increased by 4% to 6% in each cycle and the mean femoral neck bone density increased by 4.1% and 2.1% during the first two cycles, but the radial bone density did not change. The placebo group showed no statistical change in bone mass at any site. Compared with the placebo group, the sodium fluoride group had a lower individual new vertebral fracture rate (0.057/patient cycle compared with 0.204/patient cycle, P = 0.017), a higher fracture-free rate (83.3% compared with 64.7%, P = 0.042), and a lower group fracture rate (0.085/patient cycle compared with 0.239/patient cycle, P = 0.006). The side-effect profile was similar for the two groups; no patient developed microfractures, hip fractures, or blood loss anemia. CONCLUSIONS Intermittent slow-release sodium fluoride plus continuous Calcium Citrate, administered for about 2.5 years, inhibits new vertebral fractures, increases the mean spinal bone mass without decreasing the radial shaft bone density, and is safe to use.

  • Calcium Citrate without aluminum antacids does not cause aluminum retention in patients with functioning kidneys
    Bone and Mineral, 1993
    Co-Authors: Khashayar Sakhaee, Joseph E Zerwekh, John R Poindexter, Cindy L Wabner, John B Copley, Laura Pak, Charles Y.c. Pak
    Abstract:

    Summary It has been suggested that Calcium Citrate might enhance aluminum absorption from food, posing a threat of aluminum toxicity even in patients with normal renal function. We therefore measured serum and urinary aluminum before and following Calcium Citrate therapy in patients with moderate renal failure and in normal subjects maintained on constant metabolic diets with known aluminum content (967–1034 µmol/day, or 26.1–27.9 mg/day, in patients and either 834 or 1579 µmol/day, or 22.5 and 42.6 mg/day, in normal subjects). Seven patients with moderate renal failure (endogenous creatinine clearance of 43 ml/ min) took 50 mmol(2 g) Calcium/day as effervescent Calcium Citrate with meals for 17 days. Eight normal women received 25 mmol (1 g) Calcium/day as triCalcium diCitrate tablets with meals for 7 days. In patients with moderate renal failure, serum and urinary aluminum were normal before treatment at 489 ± 293 SD nmol/l (13.2 ± 7.9 µg/l) and 767 ± 497 nmol/day (20.7 ± 13.4 µg/day), respectively. They remained within normal limits and did not change significantly during Calcium Citrate treatment (400 ± 148 nmol/l and 600 ± 441 nmol/day, respectively). Similarly, no significant change in serum and urinary aluminum was detected in normal women during Calcium Citrate administration (271 ± 59 vs 293 ± 85 nmol/l and 515 ± 138 vs 615 ± 170 nmol/day, respectively). In addition, skeletal bone aluminum content did not change significantly in 14 osteoporotic patients (endogenous creatinine clearance of 68.5 ml/min) treated for 24 months with Calcium Citrate, 10 mmol Calcium twicelday separately from meals (29.3 ± 13.9 ng/mg ash bone to 27.9 ± 10.4, P=0.727). In them, histomorphometric examination did not show any evidence of mineralization defect. Thus, Calcium Citrate given alone without aluminum-containing drugs does not pose a risk of aluminum toxicity in subjects with normal or functioning kidneys, when it is administered on an empty stomach at a recommended dose of 20 mmol Calcium/day.

Jean Herzog - One of the best experts on this subject based on the ideXlab platform.

  • slow release sodium fluoride in the management of postmenopausal osteoporosis a randomized controlled trial
    Annals of Internal Medicine, 1994
    Co-Authors: Charles Y.c. Pak, Khashayar Sakhaee, John R Poindexter, Veronica K Piziak, Roy D Peterson, Neil A Breslau, Peggy Boyd, Jean Herzog
    Abstract:

    OBJECTIVE To test whether intermittent treatment with slow-release sodium fluoride and continuous Calcium Citrate supplementation inhibits vertebral fractures without causing fluoride complications. DESIGN A placebo-controlled, randomized trial. SETTING Outpatient setting of specialty clinics in Dallas and Temple, Texas. INTERVENTIONS Slow-release sodium fluoride (25 mg twice daily) in repeated 14-month cycles (12 months on treatment followed by 2 months off treatment) compared with placebo. Both groups took Calcium Citrate (400 mg Calcium twice daily) continuously. PATIENTS 110 patients with postmenopausal osteoporosis were randomly assigned to two groups. In the slow-release sodium fluoride group, 48 of 54 patients completed more than 1 cycle of treatment (mean, 2.44 cycles/patient), whereas 51 of 56 patients in the placebo group completed at least 1 cycle (mean, 2.14 cycles/patient) in this interim analysis. MEASUREMENTS Vertebral fracture rate and lumbar bone mineral content. Vertebral fractures were quantified from yearly radiographs. Bone mass was determined annually by densitometry. RESULTS In the sodium fluoride group, the mean L2 to L4 bone mineral content increased by 4% to 6% in each cycle and the mean femoral neck bone density increased by 4.1% and 2.1% during the first two cycles, but the radial bone density did not change. The placebo group showed no statistical change in bone mass at any site. Compared with the placebo group, the sodium fluoride group had a lower individual new vertebral fracture rate (0.057/patient cycle compared with 0.204/patient cycle, P = 0.017), a higher fracture-free rate (83.3% compared with 64.7%, P = 0.042), and a lower group fracture rate (0.085/patient cycle compared with 0.239/patient cycle, P = 0.006). The side-effect profile was similar for the two groups; no patient developed microfractures, hip fractures, or blood loss anemia. CONCLUSIONS Intermittent slow-release sodium fluoride plus continuous Calcium Citrate, administered for about 2.5 years, inhibits new vertebral fractures, increases the mean spinal bone mass without decreasing the radial shaft bone density, and is safe to use.