Sample records for acid prevents calcium

  1. Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis.

    PubMed

    Adeyemi, Oladipupo; Alvarez-Laviada, Anita; Schultz, Francisca; Ibrahim, Effendi; Trauner, Michael; Williamson, Catherine; Glukhov, Alexey V; Gorelik, Julia

    2017-01-01

    Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP) are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA) has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated. High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM). Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes. TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05) and slowed ventricular conduction velocity (CV) by 38.9±5.1% (P<0.05) exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T) blocker mibefradil 1μM (23.0±6.2%, P<0.05), but not with the L-type calcium current (ICa,L) blocker nifedipine 1μM (6.9±6.6%, NS). The sodium channel blocker lidocaine (30μM) reduced CV by 60.4±4.5% (P<0.05). UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (-10.2±1.5 versus -5.5±0.9 pA/pF, P<0.05) and neonatal rat ventricular myocytes (-22.3±1.1 versus -9.6±0.8 pA/pF, P<0.0001), whereas UDCA had limited efficacy on the ICa,L. Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA.

  2. Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis

    PubMed Central

    Adeyemi, Oladipupo; Alvarez-Laviada, Anita; Schultz, Francisca; Ibrahim, Effendi; Trauner, Michael; Williamson, Catherine; Glukhov, Alexey V.

    2017-01-01

    Background Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP) are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA) has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated. Methods High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM). Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes. Results TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05) and slowed ventricular conduction velocity (CV) by 38.9±5.1% (P<0.05) exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T) blocker mibefradil 1μM (23.0±6.2%, P<0.05), but not with the L-type calcium current (ICa,L) blocker nifedipine 1μM (6.9±6.6%, NS). The sodium channel blocker lidocaine (30μM) reduced CV by 60.4±4.5% (P<0.05). UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (−10.2±1.5 versus −5.5±0.9 pA/pF, P<0.05) and neonatal rat ventricular myocytes (−22.3±1.1 versus −9.6±0.8 pA/pF, P<0.0001), whereas UDCA had limited efficacy on the ICa,L. Conclusion Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA. PMID:28934223

  3. Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo.

    PubMed

    Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun; Park, Jeong-Sook; Myung, Chang-Seon

    2018-01-01

    Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the C max value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their T max values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.

  4. Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo

    PubMed Central

    Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun

    2018-01-01

    Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the Cmax value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their Tmax values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders. PMID:29302210

  5. Ferulic acid prevents cerebral ischemic injury-induced reduction of hippocalcin expression.

    PubMed

    Koh, Phil-Ok

    2013-07-01

    Intracellular calcium overload is a critical pathophysiological factor in ischemic injury. Hippocalcin is a neuronal calcium sensor protein that buffers intracellular calcium levels and protects cells from apoptotic stimuli. Ferulic acid exerts a neuroprotective effect in cerebral ischemia through its anti-oxidant and anti-inflammation activity. This study investigated whether ferulic acid contributes to hippocalcin expression during cerebral ischemia and glutamate exposure-induced neuronal cell death. Rats were immediately treated with vehicle or ferulic acid (100 mg/kg, i.v.) after middle cerebral artery occlusion (MCAO). Brain tissues were collected 24 h after MCAO and followed by assessment of cerebral infarct. Ferulic acid reduced MCAO-induced infarct regions. A proteomics approach elucidated a decrease in hippocalcin in MCAO-operated animals, ferulic acid attenuates the injury-induced decrease in hippocalcin expression. Reverse transcription-polymerase chain reaction and Western blot analyses confirmed that ferulic acid prevents the injury-induced decrease in hippocalcin. In cultured HT22 hippocampal cells, glutamate exposure increased the intracellular Ca(2+) levels, whereas ferulic acid attenuated this increase. Moreover, ferulic acid attenuated the glutamate toxicity-induced decrease in hippocalcin expression. These findings can suggest the possibility that ferulic acid exerts a neuroprotective effect through modulating hippocalcine expression and regulating intracellular calcium levels. Copyright © 2013 Wiley Periodicals, Inc.

  6. Plasma oxalic acid and calcium levels in oxalate poisoning

    PubMed Central

    Zarembski, P. M.; Hodgkinson, A.

    1967-01-01

    Observations are reported on five cases of suicide or attempted suicide by poisoning with oxalic acid or ethylene glycol. Elevated oxalic acid levels were observed in the plasma, stomach contents, and a number of tissues. Raised oxalic acid levels in plasma were associated with reduced total and ultrafilterable calcium levels. It is suggested that the reduction in plasma total calcium level is due mainly to the deposition of calcium oxalate in the soft tissues, but inhibition of the parathyroid glands may be a contributory factor. Microscopic examination of various tissues indicated that oxalic acid is deposited in the tissues in two forms: (1) crystalline calcium oxalate dihydrate in the kidney and (2) a non-crystalline complex of calcium oxalate and lipid in liver and other tissues. PMID:5602563

  7. In vitro study of the effect of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate on acid-softened enamel.

    PubMed

    Rege, Aarti; Heu, Rod; Stranick, Michael; Sullivan, Richard J

    2014-01-01

    To investigate the possible mode of action of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and sodium monofluorophosphate in delivering the benefits of preventing acid erosion and rehardening acid-softened enamel. The surfaces of acid-softened bovine enamel specimens were evaluated after application of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate in vitro. Scanning Electron Microscopy (SEM), Electronic Spectrometry for Chemical Analysis (ESCA), and Secondary Ion Mass Spectrometry (SIMS) were used to characterize the enamel surfaces. Exposure of pristine enamel surfaces to citric acid resulted in clear roughening of the surface. Multiple applications of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to the surface of the enamel resulted in the disappearance of the microscopic voids observed by SEM as a function of treatment applications. The ESCA analysis demonstrated that both the nitrogen and carbonate levels increased as the number of treatments increased, which provides evidence that arginine and calcium carbonate were bound to the surface. Observance of arginine's signature mass fragmentation pattern by SIMS analysis confirmed the identity of arginine on the enamel surface. A series of in vitro experiments has demonstrated a possible mode of action by which a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate delivers the benefits of preventing acid erosion and rehardening acid-softened enamel. The combination of arginine and calcium carbonate adheres to the enamel surface and helps to fill the microscopic gaps created by acid, which in turn helps repair the enamel and provides a protective coating against future acid attacks.

  8. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as diphosphoric acid, calcium...

  9. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as diphosphoric acid, calcium...

  10. 40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Diphosphoric acid, calcium salt (1:1... Specific Chemical Substances § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as diphosphoric acid, calcium...

  11. The role of calcium in improving photosynthesis and related physiological and biochemical attributes of spring wheat subjected to simulated acid rain.

    PubMed

    Dolatabadian, Aria; Sanavy, Seyed Ali Mohammad Modarres; Gholamhoseini, Majid; Joghan, Aydin Khodaei; Majdi, Mohammad; Kashkooli, Arman Beyraghdar

    2013-04-01

    The response of photosynthesis parameters, catalase, superoxide dismutase and peroxidase activity, malondialdehyde, proline, chlorophyll, yield and yield components to foliar application of calcium and simulated acid rain in wheat were investigated. Foliar treatment of calcium led to significant increases in the photosynthesis rate, transpiration rate, stomatal conductance, proline, chlorophyll, yield and yield components in plants subjected to acid rain. Antioxidant enzyme activity and lipid peroxidation in the wheat leaves decreased because of calcium foliar application. Calcium hindered degradation of the rubisco subunits under acid rain treatment compared with water-treated plants. Results suggest that acid rain induces the production of free radicals resulting in lipid peroxidation of the cell membrane so that significant increase in antioxidant enzyme activity was observed. In addition, photosynthetic parameters i.e. photosynthesis rate, transpiration rate and stomatal conductance were drastically suppressed by acid rain. The cellular damage caused by free radicals might be reduced or prevented by a protective metabolism including antioxidative enzymes and calcium. We report that foliar application of calcium before acid rain may ameliorate the adverse effects of acid rain in wheat plants.

  12. CALCIUM-INDUCED LIPID PEROXIDATION IS MEDIATED BY RHODNIUS HEME-BINDING PROTEIN (RHBP) AND PREVENTED BY VITELLIN.

    PubMed

    Paes, Marcia C; Silveira, Alan B; Ventura-Martins, Guilherme; Luciano, Monalisa; Coelho, Marsen G P; Todeschini, Adriane R; Bianconi, M Lucia; Atella, Georgia C; Silva-Neto, Mário A C

    2015-10-01

    Lipid peroxidation is promoted by the quasi-lipoxygenase (QL) activity of heme proteins and enhanced by the presence of free calcium. Unlike mammalian plasma, the hemolymph of Rhodnius prolixus, a vector of Chagas disease, contains both a free heme-binding protein (RHBP) and circulating lipoproteins. RHBP binds and prevents the heme groups of the proteins from participating in lipid peroxidation reactions. Herein, we show that despite being bound to RHBP, heme groups promote lipid peroxidation through a calcium-dependent QL reaction. This reaction is readily inhibited by the presence of ethylene glycol tetraacetic acid (EGTA), the antioxidant butylated hydroxytoluene or micromolar levels of the main yolk phosphoprotein vitellin (Vt). The inhibition of lipid peroxidation is eliminated by the in vitro dephosphorylation of Vt, indicating that this reaction depends on the interaction of free calcium ions with negatively charged phosphoamino acids. Our results demonstrate that calcium chelation mediated by phosphoproteins occurs via an antioxidant mechanism that protects living organisms from lipid peroxidation. © 2015 Wiley Periodicals, Inc.

  13. Calcium leaching behavior of cementitious materials in hydrochloric acid solution.

    PubMed

    Yang, Huashan; Che, Yujun; Leng, Faguang

    2018-06-11

    The calcium leaching behavior of cement paste and silica fume modified calcium hydroxide paste, exposed to hydrochloric acid solution, is reported in this paper. The kinetic of degradation was assessed by the changes of pH of hydrochloric acid solution with time. The changes of compressive strength of specimens in hydrochloric acid with time were tested. Hydration products of leached specimens were also analyzed by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG), and atomic force microscope (AFM). Tests results show that there is a dynamic equilibrium in the supply and consumption of calcium hydroxide in hydrochloric acid solution, which govern the stability of hydration products such as calcium silicate hydrate (C-S-H). The decrease of compressive strength indicates that C-S-H are decomposed due to the lower concentration of calcium hydroxide in the pore solution than the equilibrium concentration of the hydration products. Furthermore, the hydration of unhydrated clinker delayed the decomposition of C-S-H in hydrochloric acid solution due to the increase of calcium hydroxide in pore solution of cementitious materials.

  14. The Role of Calcium in Prevention and Treatment of Osteoporosis.

    ERIC Educational Resources Information Center

    Heaney, Robert P.

    1987-01-01

    Osteoporosis results from several factors. Calcium deficiency is only one, and high calcium intake will prevent only those cases in which calcium is the limiting factor. Calcium cannot reverse, but only arrest, bone loss. A high calcium intake for every member of the population is advocated. (Author/MT)

  15. Calcium ion binding to a soil fulvic acid using a donnan potential model

    USGS Publications Warehouse

    Marinsky, J.A.; Mathuthu, A.; Ephraim, J.H.; Reddy, M.M.

    1999-01-01

    Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 X 10-4 moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log ??app) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log ??app = 2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential corrrection term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log??= 1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. ?? by Oldenbourg Wissenschaftsverlag, Mu??nchen.

  16. Calcium extraction from brine water and seawater using oxalic acid

    NASA Astrophysics Data System (ADS)

    Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

    2017-01-01

    Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

  17. Calcium in the prevention of postmenopausal osteoporosis: EMAS clinical guide.

    PubMed

    Cano, Antonio; Chedraui, Peter; Goulis, Dimitrios G; Lopes, Patrice; Mishra, Gita; Mueck, Alfred; Senturk, Levent M; Simoncini, Tommaso; Stevenson, John C; Stute, Petra; Tuomikoski, Pauliina; Rees, Margaret; Lambrinoudaki, Irene

    2018-01-01

    Postmenopausal osteoporosis is a highly prevalent disease. Prevention through lifestyle measures includes an adequate calcium intake. Despite the guidance provided by scientific societies and governmental bodies worldwide, many issues remain unresolved. To provide evidence regarding the impact of calcium intake on the prevention of postmenopausal osteoporosis and critically appraise current guidelines. Literature review and consensus of expert opinion. The recommended daily intake of calcium varies between 700 and 1200mg of elemental calcium, depending on the endorsing source. Although calcium can be derived either from the diet or supplements, the former source is preferred. Intake below the recommended amount may increase fragility fracture risk; however, there is no consistent evidence that calcium supplementation at, or above, recommended levels reduces risk. The addition of vitamin D may minimally reduce fractures, mainly among institutionalised people. Excessive intake of calcium, defined as higher than 2000mg/day, can be potentially harmful. Some studies demonstrated harm even at lower dosages. An increased risk for cardiovascular events, urolithiasis and even fractures has been found in association with excessive calcium intake, but this issue remains unresolved. In conclusion, an adequate intake of calcium is recommended for general bone health. Excessive calcium intake seems of no benefit, and could possibly be harmful. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. [Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

    PubMed

    Yan, Hong-mei; Zhang, Zhen-hai; Jia, Xiao-bin; Jiang, Yan-rong; Sun, E

    2015-05-01

    Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

  19. Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

    PubMed

    Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

    2017-07-17

    Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

  20. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.

    PubMed

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

    2015-01-01

    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  1. Acidic Calcium Stores of Saccharomyces cerevisiae

    PubMed Central

    Cunningham, Kyle W.

    2011-01-01

    Fungi and animals constitute sister kingdoms in the eukaryotic domain of life. The major classes of transporters, channels, sensors, and effectors that move and respond to calcium ions were already highly networked in the common ancestor of fungi and animals. Since that time, some key components of the network have been moved, altered, relocalized, lost, or duplicated in the fungal and animal lineages and at the same time some of the regulatory circuitry has been dramatically rewired. Today the calcium transport and signaling networks in fungi provide a fresh perspective on the scene that has emerged from studies of the network in animal cells. This review provides an overview of calcium signaling networks in fungi, particularly the model yeast Saccharomyces cerevisiae, with special attention to the dominant roles of acidic calcium stores in fungal cell physiology. PMID:21377728

  2. Calcium supplementation prevents endothelial cell activation: possible relevance to preeclampsia.

    PubMed

    Chen, Qi; Tong, Mancy; Wu, Man; Stone, Peter R; Snowise, Saul; Chamley, Lawrence W

    2013-09-01

    Preeclampsia is a leading cause of maternal and fetal mortality and morbidity. A hallmark of preeclampsia is endothelial cell dysfunction/activation in response to 'toxins' from the placenta. Necrotic trophoblastic debris (NTD) is one possible placental toxin and other activators of endothelial cells include inflammatory cytokines. Calcium supplementation appears to protect 'at-risk' women from developing preeclampsia but how is unclear. Placental explants were cultured with interleukin-6 (IL-6) in varied concentrations of calcium. The resultant trophoblastic debris was exposed to endothelial cells. Endothelial cells were exposed to activators including NTD, IL-6, and preeclamptic sera in the presence of varied concentrations of calcium and activation monitored by quantifying cell surface markers by ELISA. Raising the levels of calcium did not prevent the IL-6-induced shedding of NTD from placental explants but did prevent the activation of endothelial cells in response to IL-6, preeclamptic sera, or NTD. Reducing the level of calcium directly induced the activation of endothelial cells. Inhibiting nitric oxide synthetase ablated the ability of high calcium levels to protect endothelial cell activation. The activity of endothelial cell nitric oxide synthetase was blocked with L-N-nitroarginine methyl ester. Our results demonstrate calcium levels do not affect the shedding of trophoblastic debris but are important to endothelial cell activation and supplemental calcium may reverse the activation of the endothelium in preeclamptic women. These results may in part explain the benefits of calcium supplementation in the reduction of risk for developing preeclampsia and provide in-vitro mechanistic support for the use of calcium supplementation in at-risk women.

  3. Gibberellic acid promoting phytic acid degradation in germinating soybean under calcium lactate treatment.

    PubMed

    Hui, Qianru; Wang, Mian; Wang, Pei; Ma, Ya; Gu, Zhenxin; Yang, Runqiang

    2018-01-01

    Phytic acid as a phosphorus storage vault provides phosphorus for plant development. It is an anti-nutritional factor for humans and some animals. However, its degradation products lower inositol phosphates have positive effects on human health. In this study, the effect of gibberellic acid (GA) on phytic acid degradation under calcium lactate (Ca) existence was investigated. The results showed that Ca + GA treatment promoted the growth status, hormone metabolism and phytic acid degradation in germinating soybean. At the same time, the availability of phosphorus, the activity of phytic acid degradation-associated enzyme and phosphoinositide-specific phospholipase C (PI-PLC) increased. However, the relative genes expression of phytic acid degradation-associated enzymes did not vary in accordance with their enzymes activity. The results revealed that GA could mediate the transport and function of calcium and a series of physiological and biochemical changes to regulate phytic acid degradation of soybean sprouts. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Mechanism of Calcium Lactate Facilitating Phytic Acid Degradation in Soybean during Germination.

    PubMed

    Hui, Qianru; Yang, Runqiang; Shen, Chang; Zhou, Yulin; Gu, Zhenxin

    2016-07-13

    Calcium lactate facilitates the growth and phytic acid degradation of soybean sprouts, but the mechanism is unclear. In this study, calcium lactate (Ca) and calcium lactate with lanthanum chloride (Ca+La) were used to treat soybean sprouts to reveal the relevant mechanism. Results showed that the phytic acid content decreased and the availability of phosphorus increased under Ca treatment. This must be due to the enhancement of enzyme activity related to phytic acid degradation. In addition, the energy metabolism was accelerated by Ca treatment. The energy status and energy metabolism-associated enzyme activity also increased. However, the transmembrane transport of calcium was inhibited by La(3+) and concentrated in intercellular space or between the cell wall and cell membrane; thus, Ca+La treatment showed reverse results compared with those of Ca treatment. Interestingly, gene expression did not vary in accordance with their enzyme activity. These results demonstrated that calcium lactate increased the rate of phytic acid degradation by enhancing growth, phosphorus metabolism, and energy metabolism.

  5. Perlwapin, an Abalone Nacre Protein with Three Four-Disulfide Core (Whey Acidic Protein) Domains, Inhibits the Growth of Calcium Carbonate Crystals

    PubMed Central

    Treccani, Laura; Mann, Karlheinz; Heinemann, Fabian; Fritz, Monika

    2006-01-01

    We have isolated a new protein from the nacreous layer of the shell of the sea snail Haliotis laevigata (abalone). Amino acid sequence analysis showed the protein to consist of 134 amino acids and to contain three sequence repeats of ∼40 amino acids which were very similar to the well-known whey acidic protein domains of other proteins. The new protein was therefore named perlwapin. In addition to the major sequence, we identified several minor variants. Atomic force microscopy was used to explore the interaction of perlwapin with calcite crystals. Monomolecular layers of calcite crystals dissolve very slowly in deionized water and recrystallize in supersaturated calcium carbonate solution. When perlwapin was dissolved in the supersaturated calcium carbonate solution, growth of the crystal was inhibited immediately. Perlwapin molecules bound tightly to distinct step edges, preventing the crystal layers from growing. Using lower concentrations of perlwapin in a saturated calcium carbonate solution, we could distinguish native, active perlwapin molecules from denaturated ones. These observations showed that perlwapin can act as a growth inhibitor for calcium carbonate crystals in saturated calcium carbonate solution. The function of perlwapin in nacre growth may be to inhibit the growth of certain crystallographic planes in the mineral phase of the polymer/mineral composite nacre. PMID:16861275

  6. Study on Treatment of acidic and highly concentrated fluoride waste water using calcium oxide-calcium chloride

    NASA Astrophysics Data System (ADS)

    Ren, T.; Gao, X. R.; Zheng, T.; Wang, P.

    2016-08-01

    There are problems with treating acidic waste water containing high concentration fluorine by chemical precipitation, including the low sludge setting velocity and the high difficulty of reaching the criterion. In Heilongjiang province, a graphite factory producing high-purity graphite generates acidic waste water with a high concentration of fluorine. In this paper, the effect of removals on the concentration of fluoride with the combined treatment of calcium oxide and calcium chloride were discussed with regard to acid waste water. The study improved the sludge characteristics by using polyacrylamide (PAM) and polymeric aluminum chloride (PAC). The effect of different coagulants on sludge was evaluated by the sludge settlement ratio (SV), sludge volume index (SVI) and sludge moisture content. The results showed that the optimal combination for 100 ml waste water was calcium oxide addition amount of 14 g, a calcium chloride addition amount of 2.5 g, a PAM addition amount of 350 mg/L, and the effluent fluoride concentration was below 6 mg/L. PAM significantly improved the sludge settling velocity. The sludge settlement ratio reduced from 87.6% to 60%. The process for wastewater treatment was easily operated and involved low expenditure.

  7. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  8. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  9. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  10. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  11. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  12. Method of repressing the precipitation of calcium fluozirconate

    DOEpatents

    Newby, B.J.; Rhodes, D.W.

    1973-12-25

    Boric acid or a borate salt is added to aqueous solutions of fluoride containing radioactive wastes generated during the reprocessing of zirconium alloy nuclear fuels which are to be converted to solid form by calcining in a fluidized bed. The addition of calcium nitrate to the aqueous waste solutions to prevent fluoride volatility during calcination, causes the precipitation of calcium fluozirconate, which tends to form a gel at fluoride concentrations of 3.0 M or greater. The boron containing species introduced into the solution by the addition of the boric acid or borate salt retard the formation of the calcium fluozirconate precipitate and prevent formation of the gel. These boron containing species can be introduced into the solution by the addition of a borate salt but preferably are introduced by the addition of an aqueous solution of boric acid. (Official Gazette)

  13. [Calcium kidney stones. Diagnostic and preventive prospects].

    PubMed

    Arcidiacono, T; Terranegra, A; Biasion, R; Soldati, L; Vezzoli, G

    2007-01-01

    Kidney stone disease is one of the main causes of hospitalization in Italy. Its prevalence increased in the last century and is probably still increasing. The pathogenesis of the disease is not known, although two main theories have been elaborated. The first hypothesizes that hydroxyapatite deposition in the interstitium of the renal papillae (Randall's plaque) precedes urinary calcium oxalate precipitation on the ulcered surface of the papilla to form a stone. The second presumes the tubular lumen of Bellini's duct to be the site where calcium-oxalate salts precipitate to form the nucleus for stone formation within the urinary tract. These pathogenetic processes may be favored by different dietary and genetic factors. The genes involved are not known, although many studies have been performed. Polymorphisms of genes coding for the vitamin D receptor, calcium-sensing receptor, interleukin-1 receptor antagonist, and urokinase were found to be associated with kidney stones, but these results have not been replicated. Different nutrients are suspected to predispose patients to calcium kidney stone disease. A high intake of animal proteins, sodium, vitamin C and oxalate has been implicated in stone formation, whereas calcium, alkalis and phytate may have a protective effect. The prevention of calcium stone formation is based on the recognition of risk factors like those already mentioned here. Furthermore, a family history of kidney stones may be useful in identifying subjects predisposed to become calcium stone formers. However, the expectations of the scientific community are turned to the advances in genetics and to the findings of genetic studies, which may provide diagnostic tools and criteria to define the risk profile of the single individual.

  14. Severe leaching of calcium ions from fir needles caused by acid fog.

    PubMed

    Igawa, Manabu; Kase, Toshiyuki; Satake, Kosuke; Okochi, Hiroshi

    2002-01-01

    We have measured the components of the throughfall under fir trees (Abies firma) in the field around Mt. Oyama, where the forest appears to be declining, for the period 1994-1998. Exposure experiments of a simulated acid fog to fir twigs were performed under field conditions. There was a similarity between the acid response in the field and that in the laboratory. In both studies, the severe leaching of calcium ions from the needle surface was caused by exposure to acid fog. We also applied acid fog to fir seedlings over 1 year and observed a decrease in the growth of the seedlings due to this application in the dormant season. These results suggest that the severe leaching of calcium ions due to acid fog may cause the deficiency of calcium and be responsible for the decline of the fir trees.

  15. Antimicrobial Effect of Calcium Chloride Alone and Combined with Lactic Acid Injected into Chicken Breast Meat

    PubMed Central

    Alahakoon, Amali U.; Jayasena, Dinesh D.; Jung, Samooel; Kim, Sun Hyo

    2014-01-01

    Chicken breast meat was injected with calcium chloride alone and in combination with lactic acid (0.01% and 0.002%, respectively). The inhibitory effects of the treatments on microbial growth were determined in the injected chicken breast meat stored at 4°C under aerobic packaging condition for 0, 3, and 7 d. Calcium chloride combined with 0.002% and 0.01% lactic acid reduced microbial counts by 0.14 and 1.08 Log CFU/g, respectively, however, calcium chloride alone was unable to inhibit microbial growth. Calcium chloride combined with 0.01% lactic acid was the most effective antimicrobial treatment and resulted in the highest initial redness value. Calcium chloride alone and combined with lactic acid suppressed changes in pH and the Hunter color values during storage. However, injection of calcium chloride and lactic acid had adverse effects on lipid oxidation and sensory characteristics. The higher TBARS values were observed in samples treated with calcium chloride and lactic acid when compared to control over the storage period. Addition of calcium chloride and lactic acid resulted in lower sensory scores for parameters tested, except odor and color, compared to control samples. Therefore, the formulation should be improved in order to overcome such defects prior to industrial application. PMID:26760942

  16. Kit W-sh Mutation Prevents Cancellous Bone Loss during Calcium Deprivation.

    PubMed

    Lotinun, Sutada; Suwanwela, Jaijam; Poolthong, Suchit; Baron, Roland

    2018-01-01

    Calcium is essential for normal bone growth and development. Inadequate calcium intake increases the risk of osteoporosis and fractures. Kit ligand/c-Kit signaling plays an important role in regulating bone homeostasis. Mice with c-Kit mutations are osteopenic. The present study aimed to investigate whether impairment of or reduction in c-Kit signaling affects bone turnover during calcium deprivation. Three-week-old male WBB6F1/J-Kit W /Kit W-v /J (W/W v ) mice with c-Kit point mutation, Kit W-sh /HNihrJaeBsmJ (W sh /W sh ) mice with an inversion mutation in the regulatory elements upstream of the c-Kit promoter region, and their wild-type controls (WT) were fed either a normal (0.6% calcium) or a low calcium diet (0.02% calcium) for 3 weeks. μCT analysis indicated that both mutants fed normal calcium diet had significantly decreased cortical thickness and cancellous bone volume compared to WT. The low calcium diet resulted in a comparable reduction in cortical bone volume and cortical thickness in the W/W v and W sh /W sh mice, and their corresponding controls. As expected, the low calcium diet induced cancellous bone loss in the W/W v mice. In contrast, W sh /W sh cancellous bone did not respond to this diet. This c-Kit mutation prevented cancellous bone loss by antagonizing the low calcium diet-induced increase in osteoblast and osteoclast numbers in the W sh /W sh mice. Gene expression profiling showed that calcium deficiency increased Osx, Ocn, Alp, type I collagen, c-Fms, M-CSF, and RANKL/OPG mRNA expression in controls; however, the W sh mutation suppressed these effects. Our findings indicate that although calcium restriction increased bone turnover, leading to osteopenia, the decreased c-Kit expression levels in the W sh /W sh mice prevented the low calcium diet-induced increase in cancellous bone turnover and bone loss but not the cortical bone loss.

  17. Klotho Prevents Renal Calcium Loss

    PubMed Central

    Alexander, R. Todd; Woudenberg-Vrenken, Titia E.; Buurman, Jan; Dijkman, Henry; van der Eerden, Bram C. J.; van Leeuwen, Johannes P.T.M.; Bindels, René J.

    2009-01-01

    Disturbed calcium (Ca2+) homeostasis, which is implicit to the aging phenotype of klotho-deficient mice, has been attributed to altered vitamin D metabolism, but alternative possibilities exist. We hypothesized that failed tubular Ca2+ absorption is primary, which causes increased urinary Ca2+ excretion, leading to elevated 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and its sequelae. Here, we assessed intestinal Ca2+ absorption, bone densitometry, renal Ca2+ excretion, and renal morphology via energy-dispersive x-ray microanalysis in wild-type and klotho−/− mice. We observed elevated serum Ca2+ and fractional excretion of Ca2+ (FECa) in klotho−/− mice. Klotho−/− mice also showed intestinal Ca2+ hyperabsorption, osteopenia, and renal precipitation of calcium-phosphate. Duodenal mRNA levels of transient receptor potential vanilloid 6 (TRPV6) and calbindin-D9K increased. In the kidney, klotho−/− mice exhibited increased expression of TRPV5 and decreased expression of the sodium/calcium exchanger (NCX1) and calbindin-D28K, implying a failure to absorb Ca2+ through the distal convoluted tubule/connecting tubule (DCT/CNT) via TRPV5. Gene and protein expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D-1-α-hydroxylase (1αOHase), and calbindin-D9K excluded renal vitamin D resistance. By modulating the diet, we showed that the renal Ca2+ wasting was not secondary to hypercalcemia and/or hypervitaminosis D. In summary, these findings illustrate a primary defect in tubular Ca2+ handling that contributes to the precipitation of calcium-phosphate in DCT/CNT. This highlights the importance of klotho to the prevention of renal Ca2+ loss, secondary hypervitaminosis D, osteopenia, and nephrocalcinosis. PMID:19713312

  18. Multiparameter imaging of calcium and abscisic acid and high-resolution quantitative calcium measurements using R-GECO1-mTurquoise in Arabidopsis.

    PubMed

    Waadt, Rainer; Krebs, Melanie; Kudla, Jörg; Schumacher, Karin

    2017-10-01

    Calcium signals occur in specific spatio-temporal patterns in response to various stimuli and are coordinated with, for example, hormonal signals, for physiological and developmental adaptations. Quantification of calcium together with other signalling molecules is required for correlative analyses and to decipher downstream calcium-decoding mechanisms. Simultaneous in vivo imaging of calcium and abscisic acid has been performed here to investigate the interdependence of the respective signalling processes in Arabidopsis thaliana roots. Advanced ratiometric genetically encoded calcium indicators have been generated and in vivo calcium calibration protocols were established to determine absolute calcium concentration changes in response to auxin and ATP. In roots, abscisic acid induced long-term basal calcium concentration increases, while auxin triggered rapid signals in the elongation zone. The advanced ratiometric calcium indicator R-GECO1-mTurquoise exhibited an increased calcium signal resolution compared to commonly used Förster resonance energy transfer-based indicators. Quantitative calcium measurements in Arabidopsis root tips using R-GECO1-mTurquoise revealed detailed maps of absolute calcium concentration changes in response to auxin and ATP. Calcium calibration protocols using R-GECO1-mTurquoise enabled high-resolution quantitative imaging of resting cytosolic calcium concentrations and their dynamic changes that revealed distinct hormonal and ATP responses in roots. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  20. Nutritional approach to preeclampsia prevention.

    PubMed

    Achamrah, Najate; Ditisheim, Agnès

    2018-05-01

    Although not fully understood, the physiopathology of preeclampsia is thought to involve an abnormal placentation, diffuse endothelial cell dysfunction and increased systemic inflammation. As micronutrients play a key role in placental endothelial function, oxidative stress and expression of angiogenic factors, periconceptional micronutrient supplementation has been proposed to reduce the risk of preeclampsia. However, recent studies reported conflicting results. Calcium intake (>1 g/day) may reduce the risk of preeclampsia in women with low-calcium diet. Data from recently updated Cochrane reviews did not support routine supplementation of vitamins C, E or D for either the prevention or treatment of preeclampsia. Evidences are also poor to support zinc or folic acid supplementation for preeclampsia prevention. Dark chocolate, flavonoid-rich food, and long-chain polyunsaturated fatty acids might also be candidates for prevention of preeclampsia. Through antioxidant, anti-inflammatory or vasoactive proprieties, micronutrients are good candidates for preeclampsia prevention. Calcium supplementation is recommended to prevent preeclampsia in women with low-calcium intake. Despite positive clinical and in-vitro data, strong evidence to support periconceptional supplementation of other micronutrients for preeclampsia risk-reduction is still lacking. Further studies are also needed to evaluate the benefit of nutritional supplementation such as chocolate and long-chain polyunsaturated fatty acids.

  1. Effect of zoledronic acid on serum calcium in Paget’s disease patients after educational strategies to improve calcium and vitamin D supplementation

    PubMed Central

    Bone, Henry G.; Su, Guoqin; Tan, Monique; Ozturk, Zafer E.; Aftring, Paul

    2015-01-01

    Objective: Bisphosphonates are the most effective therapeutic agents in patients with Paget’s disease of bone. As a result of their inhibition of osteoclastic activity, hypocalcemia of variable frequency and severity following intravenous bisphosphonate therapy has been reported. The present study assessed the effect of physician and patient education on adequate supplementation of calcium and vitamin D to reduce the potential risk of developing hypocalcemia following infusion of 5 mg zoledronic acid. Methods: This was an open-label, multicenter, controlled registry trial in which patients with Paget’s disease were treated with a single intravenous infusion of zoledronic acid. Physicians were provided with educational materials focusing on optimization of calcium and vitamin D supplementation following zoledronic infusion that they used to educate their patients. The primary safety variable was the percentage of patients with serum calcium level <2.07mmol/l 9–11 days after zoledronic acid infusion. Results: A total of 75 patients were evaluable in the post dose hypocalcemia safety analysis. Of these, only 1 patient had treatment-emergent hypocalcemia, with a serum calcium level of 1.92 mmol/l 4 days following therapy. Hypocalcemia-related symptoms were not reported in this patient and the serum calcium returned to normal range at 2.17 mmol/l within 1 week on oral calcium supplementation. Conclusions: These results suggest that, with optimization of calcium and vitamin D supplementation by physician and patient education, hypocalcemia is an infrequent occurrence following zoledronic acid infusion. PMID:26301065

  2. Fabrication of calcium phosphate–calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid

    PubMed Central

    Thai, Van Viet

    2010-01-01

    In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4·2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37°C. PMID:20333539

  3. Colorectal Chemoprevention with Calcium and Vitamin D | Division of Cancer Prevention

    Cancer.gov

    In this application we propose to complete CA098286, a double-blind, randomized, controlled trial of supplementation with vitamin D and/or calcium for the prevention of colorectal adenomas. The study builds on extensive epidemiological and experimental data indicating that both vitamin D and calcium have anti-neoplastic effects in the large bowel and that these agents

  4. Brittle and ductile adjustable cement derived from calcium phosphate cement/polyacrylic acid composites.

    PubMed

    Chen, Wen-Cheng; Ju, Chien-Ping; Wang, Jen-Chyan; Hung, Chun-Cheng; Chern Lin, Jiin-Huey

    2008-12-01

    Bone filler has been used over the years in dental and biomedical applications. The present work is to characterize a non-dispersive, fast setting, modulus adjustable, high bioresorbable composite bone cement derived from calcium phosphate-based cement combined with polymer and binding agents. This cement, we hope, will not swell in simulated body fluid and keep the osteogenetic properties of the dry bone and avoid its disadvantages of being brittle. We developed a calcium phosphate cement (CPC) of tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA)-polyacrylic acid with tartaric acid, calcium fluoride additives and phosphate hardening solution. The results show that while composite, the hard-brittle properties of 25wt% polyacrylic acid are proportional to CPC and mixing with additives is the same as those of the CPC without polyacrylic acid added. With an increase of polyacrylic acid/CPC ratio, the 67wt% samples revealed ductile-tough properties and 100wt% samples kept ductile or elastic properties after 24h of immersion. The modulus range of this development was from 200 to 2600MPa after getting immersed in simulated body fluid for 24h. The TTCP/DCPA-polyacrylic acid based CPC demonstrates adjustable brittle/ductile strength during setting and after immersion, and the final reaction products consist of high bioresorbable monetite/brushite/calcium fluoride composite with polyacrylic acid.

  5. Electrochemical investigation of lead-calcium alloys in sulphuric acid

    NASA Astrophysics Data System (ADS)

    Bass, K.; Ellis, S. R.; Johnson, M.; Hampson, N. A.

    The hydrogen evolution reaction from, and the cycle life (Pb /ar PbSO 4) of, a series of lead-calcium alloys (0 - 0.2 wt.% Ca) in sulphuric acid hav The exchange current density and Tafel slope for the H.R.E. increase with Ca content up to 0.05 wt.% then decrease to a value approaching that of pure The observed results are explained by: (i) preferential adsorption of calcium ions at the electrode surface; (ii) incorporation of Ca, to form a supersaturated solution, with alloys containing < 0.075 wt.% Ca; (iii) formation of an insoluble, non-conducting layer of calcium sulphate on the high content alloy.

  6. Randomized controlled trial of febuxostat versus allopurinol or placebo in individuals with higher urinary uric acid excretion and calcium stones.

    PubMed

    Goldfarb, David S; MacDonald, Patricia A; Gunawardhana, Lhanoo; Chefo, Solomon; McLean, Lachy

    2013-11-01

    Higher urinary uric acid excretion is a suspected risk factor for calcium oxalate stone formation. Febuxostat, a xanthine oxidoreductase inhibitor, is effective in lowering serum urate concentration and urinary uric acid excretion in healthy volunteers and people with gout. This work studied whether febuxostat, compared with allopurinol and placebo, would reduce 24-hour urinary uric acid excretion and prevent stone growth or new stone formation. In this 6-month, double-blind, multicenter, randomized controlled trial, hyperuricosuric participants with a recent history of calcium stones and one or more radio-opaque calcium stone ≥ 3 mm (as seen by multidetector computed tomography) received daily febuxostat at 80 mg, allopurinol at 300 mg, or placebo. The primary end point was percent change from baseline to month 6 in 24-hour urinary uric acid. Secondary end points included percent change from baseline to month 6 in size of index stone and change from baseline in the mean number of stones and 24-hour creatinine clearance. Of 99 enrolled participants, 86 participants completed the study. Febuxostat led to significantly greater reduction in 24-hour urinary uric acid (-58.6%) than either allopurinol (-36.4%; P=0.003) or placebo (-12.7%; P<0.001). Percent change from baseline in the size of the largest calcium stone was not different with febuxostat compared with allopurinol or placebo. There was no change in stone size, stone number, or renal function. No new safety concerns were noted for either drug. Febuxostat (80 mg) lowered 24-hour urinary uric acid significantly more than allopurinol (300 mg) in stone formers with higher urinary uric acid excretion after 6 months of treatment. There was no change in stone size or number over the 6-month period.

  7. Na+/H+ exchanger 3 inhibitor diminishes the amino-acid-enhanced transepithelial calcium transport across the rat duodenum.

    PubMed

    Thammayon, Nithipak; Wongdee, Kannikar; Lertsuwan, Kornkamon; Suntornsaratoon, Panan; Thongbunchoo, Jirawan; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

    2017-04-01

    Na + /H + exchanger (NHE)-3 is important for intestinal absorption of nutrients and minerals, including calcium. The previous investigations have shown that the intestinal calcium absorption is also dependent on luminal nutrients, but whether aliphatic amino acids and glucose, which are abundant in the luminal fluid during a meal, similarly enhance calcium transport remains elusive. Herein, we used the in vitro Ussing chamber technique to determine epithelial electrical parameters, i.e., potential difference (PD), short-circuit current (Isc), and transepithelial resistance, as well as 45 Ca flux in the rat duodenum directly exposed on the mucosal side to glucose or various amino acids. We found that mucosal glucose exposure led to the enhanced calcium transport, PD, and Isc, all of which were insensitive to NHE3 inhibitor (100 nM tenapanor). In the absence of mucosal glucose, several amino acids (12 mM in the mucosal side), i.e., alanine, isoleucine, leucine, proline, and hydroxyproline, markedly increased the duodenal calcium transport. An inhibitor for NHE3 exposure on the mucosal side completely abolished proline- and leucine-enhanced calcium transport, but not transepithelial transport of both amino acids themselves. In conclusion, glucose and certain amino acids in the mucosal side were potent stimulators of the duodenal calcium absorption, but only amino-acid-enhanced calcium transport was NHE3-dependent.

  8. Activation of oral trigeminal neurons by fatty acids is dependent upon intracellular calcium.

    PubMed

    Yu, Tian; Shah, Bhavik P; Hansen, Dane R; Park-York, MieJung; Gilbertson, Timothy A

    2012-08-01

    The chemoreception of dietary fat in the oral cavity has largely been attributed to activation of the somatosensory system that conveys the textural properties of fat. However, the ability of fatty acids, which are believed to represent the proximate stimulus for fat taste, to stimulate rat trigeminal neurons has remained unexplored. Here, we found that several free fatty acids are capable of activating trigeminal neurons with different kinetics. Further, a polyunsaturated fatty acid, linoleic acid (LA), activates trigeminal neurons by increasing intracellular calcium concentration and generating depolarizing receptor potentials. Ion substitution and pharmacological approaches reveal that intracellular calcium store depletion is crucial for LA-induced signaling in a subset of trigeminal neurons. Using pseudorabies virus (PrV) as a live cell tracer, we identified a subset of lingual nerve-innervated trigeminal neurons that respond to different subsets of fatty acids. Quantitative real-time PCR of several transient receptor potential channel markers in individual neurons validated that PrV labeled a subset but not the entire population of lingual-innervated trigeminal neurons. We further confirmed that the LA-induced intracellular calcium rise is exclusively coming from the release of calcium stores from the endoplasmic reticulum in this subset of lingual nerve-innervated trigeminal neurons.

  9. Activation of Oral Trigeminal Neurons by Fatty Acids is Dependent upon Intracellular Calcium

    PubMed Central

    Yu, Tian; Shah, Bhavik P.; Hansen, Dane R.; Park-York, MieJung; Gilbertson, Timothy A.

    2012-01-01

    The chemoreception of dietary fat in the oral cavity has largely been attributed to activation of the somatosensory system that conveys the textural properties of fat. However, the ability of fatty acids, which are believed to represent the proximate stimulus for fat taste, to stimulate rat trigeminal neurons has remained unexplored. Here, we found that several free fatty acids are capable of activating trigeminal neurons with different kinetics. Further, a polyunsaturated fatty acid, linoleic acid (LA), activates trigeminal neurons by increasing intracellular calcium concentration and generating depolarizing receptor potentials. Ion substitution and pharmacological approaches reveal that intracellular calcium store depletion is crucial for LA-induced signaling in a subset of trigeminal neurons. Using pseudorabies virus (PrV) as a live cell tracer, we identified a subset of lingual nerve-innervated trigeminal neurons that respond to different subsets of fatty acids. Quantitative real-time PCR of several transient receptor potential (TRP) channel markers in individual neurons validated that PrV labeled a subset but not the entire population of lingual-innervated trigeminal neurons. We further confirmed that the LA-induced intracellular calcium rise is exclusively coming from the release of calcium stores from the endoplasmic reticulum in this subset of lingual nerve-innervated trigeminal neurons. PMID:22644615

  10. Inhibitors of ORAI1 Prevent Cytosolic Calcium-Associated Injury of Human Pancreatic Acinar Cells and Acute Pancreatitis in 3 Mouse Models

    PubMed Central

    Wen, Li; Voronina, Svetlana; Javed, Muhammad A.; Awais, Muhammad; Szatmary, Peter; Latawiec, Diane; Chvanov, Michael; Collier, David; Huang, Wei; Barrett, John; Begg, Malcolm; Stauderman, Ken; Roos, Jack; Grigoryev, Sergey; Ramos, Stephanie; Rogers, Evan; Whitten, Jeff; Velicelebi, Gonul; Dunn, Michael; Tepikin, Alexei V.; Criddle, David N.; Sutton, Robert

    2015-01-01

    Background & Aims Sustained activation of the cytosolic calcium concentration induces injury to pancreatic acinar cells and necrosis. The calcium release–activated calcium modulator ORAI1 is the most abundant Ca2+ entry channel in pancreatic acinar cells; it sustains calcium overload in mice exposed to toxins that induce pancreatitis. We investigated the roles of ORAI1 in pancreatic acinar cell injury and the development of acute pancreatitis in mice. Methods Mouse and human acinar cells, as well as HEK 293 cells transfected to express human ORAI1 with human stromal interaction molecule 1, were hyperstimulated or incubated with human bile acid, thapsigargin, or cyclopiazonic acid to induce calcium entry. GSK-7975A or CM_128 were added to some cells, which were analyzed by confocal and video microscopy and patch clamp recordings. Acute pancreatitis was induced in C57BL/6J mice by ductal injection of taurolithocholic acid 3-sulfate or intravenous' administration of cerulein or ethanol and palmitoleic acid. Some mice then were given GSK-7975A or CM_128, which inhibit ORAI1, at different time points to assess local and systemic effects. Results GSK-7975A and CM_128 each separately inhibited toxin-induced activation of ORAI1 and/or activation of Ca2+ currents after Ca2+ release, in a concentration-dependent manner, in mouse and human pancreatic acinar cells (inhibition >90% of the levels observed in control cells). The ORAI1 inhibitors also prevented activation of the necrotic cell death pathway in mouse and human pancreatic acinar cells. GSK-7975A and CM_128 each inhibited all local and systemic features of acute pancreatitis in all 3 models, in dose- and time-dependent manners. The agents were significantly more effective, in a range of parameters, when given at 1 vs 6 hours after induction of pancreatitis. Conclusions Cytosolic calcium overload, mediated via ORAI1, contributes to the pathogenesis of acute pancreatitis. ORAI1 inhibitors might be developed

  11. Kynurenic Acid Prevents Cytoskeletal Disorganization Induced by Quinolinic Acid in Mixed Cultures of Rat Striatum.

    PubMed

    Pierozan, Paula; Biasibetti-Brendler, Helena; Schmitz, Felipe; Ferreira, Fernanda; Pessoa-Pureur, Regina; Wyse, Angela T S

    2018-06-01

    Kynurenic acid (KYNA) is a neuroactive metabolite of tryptophan known to modulate a number of mechanisms involved in neural dysfunction. Although its activity in the brain has been widely studied, the effect of KYNA counteracting the actions of quinolinic acid (QUIN) remains unknown. The present study aims at describing the ability of 100 μM KYNA preventing cytoskeletal disruption provoked by QUIN in astrocyte/neuron/microglia mixed culture. KYNA totally preserved cytoskeletal organization, cell morphology, and redox imbalance in mixed cultures exposed to QUIN. However, KYNA partially prevented morphological alteration in isolated primary astrocytes and failed to protect the morphological alterations of neurons caused by QUIN exposure. Moreover, KYNA prevented QUIN-induced microglial activation and upregulation of ionized calcium-binding adapter molecule 1 (Iba-1) and partially preserved tumor necrosis factor-α (TNF-α) level in mixed cultures. TNF-α level was also partially preserved in astrocytes. In addition to the mechanisms dependent on redox imbalance and microglial activation, KYNA prevented downregulation of connexin-43 and the loss of functionality of gap junctions (GJs), preserving cell-cell contact, cytoskeletal organization, and cell morphology in QUIN-treated cells. Furthermore, the toxicity of QUIN targeting the cytoskeleton of mixed cultures was not prevented by the N-methyl-D-aspartate (NMDA) antagonist MK-801. We suggest that KYNA protects the integrity of the cytoskeleton of mixed cultures by complex mechanisms including modulating microglial activation preventing oxidative imbalance and misregulated GJs leading to disrupted cytoskeleton in QUIN-treated cells. This study contributed to elucidate the molecular basis of KYNA protection against QUIN toxicity.

  12. Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures in Community-Dwelling Adults: US Preventive Services Task Force Recommendation Statement.

    PubMed

    Grossman, David C; Curry, Susan J; Owens, Douglas K; Barry, Michael J; Caughey, Aaron B; Davidson, Karina W; Doubeni, Chyke A; Epling, John W; Kemper, Alex R; Krist, Alex H; Kubik, Martha; Landefeld, Seth; Mangione, Carol M; Silverstein, Michael; Simon, Melissa A; Tseng, Chien-Wen

    2018-04-17

    Because of the aging population, osteoporotic fractures are an increasingly important cause of morbidity and mortality in the United States. Approximately 2 million osteoporotic fractures occurred in the United States in 2005, and annual incidence is projected to increase to more than 3 million fractures by 2025. Within 1 year of experiencing a hip fracture, many patients are unable to walk independently, more than half require assistance with activities of daily living, and 20% to 30% of patients will die. To update the 2013 US Preventive Services Task Force (USPSTF) recommendation on vitamin D supplementation, with or without calcium, to prevent fractures. The USPSTF reviewed the evidence on vitamin D, calcium, and combined supplementation for the primary prevention of fractures in community-dwelling adults (defined as not living in a nursing home or other institutional care setting). The review excluded studies conducted in populations with a known disorder related to bone metabolism (eg, osteoporosis or vitamin D deficiency), taking medications known to be associated with osteoporosis (eg, long-term steroids), or with a previous fracture. The USPSTF found inadequate evidence to estimate the benefits of vitamin D, calcium, or combined supplementation to prevent fractures in community-dwelling men and premenopausal women. The USPSTF found adequate evidence that daily supplementation with 400 IU or less of vitamin D and 1000 mg or less of calcium has no benefit for the primary prevention of fractures in community-dwelling, postmenopausal women. The USPSTF found inadequate evidence to estimate the benefits of doses greater than 400 IU of vitamin D or greater than 1000 mg of calcium to prevent fractures in community-dwelling postmenopausal women. The USPSTF found adequate evidence that supplementation with vitamin D and calcium increases the incidence of kidney stones. The USPSTF concludes that the current evidence is insufficient to assess the balance of the

  13. Modulation of polyepoxysuccinic acid on crystallization of calcium oxalate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Yanqing; Tang, Yongming, E-mail: tangym@njtech.edu.cn; Xu, Jinqiu

    The influence of polyepoxysuccinic acid (PESA) on the phase composition and crystal morphology of calcium oxalate was investigated in this paper. It was found that the presence of PESA inhibited the growth of the monoclinic calcium oxalate monohydrate (COM) crystal and promoted the nucleation of the tetragonal calcium oxalate dihydrate (COD). In addition, with the increase in PESA concentration, the aggregation of COD crystals was reduced but the particle size was increased. Under the conditions of low calcium-to-oxalate ratio and high CaOx concentration, PESA could not effectively stabilize the formation of COD. Based on molecular dynamic simulations, the adsorption ofmore » PESA on CaOx crystal faces was confirmed. - Graphical abstract: Introduction of PESA into crystallization solutions promotes the formation of calcium oxalate dehydrate and modifies the morphology of crystals. - Highlights: • PESA induces the formation of COD at low supersaturation. • Establishment of Ca-rich surface augments the adsorption of PESA. • At Ca/Ox=0.5 PESA cannot induce the formation of COD compared with Ca/Ox=2. • Interaction of PESA with COM faces is stronger than that with COD faces.« less

  14. Calcium supplementation commencing before or early in pregnancy, or food fortification with calcium, for preventing hypertensive disorders of pregnancy.

    PubMed

    Hofmeyr, G Justus; Manyame, Sarah

    2017-09-26

    versus control. The women (who had low antioxidant status) were in the early stages of pregnancy. We did not identify any studies where supplementation commenced pre-pregnancy. Another RCT comparing calcium versus placebo is ongoing but not yet complete. We did not identify any studies looking at any of our other planned comparisons. Calcium plus antioxidants and other supplements versus placeboWe included one small study (involving 60 women with low antioxidant levels) which was conducted in an academic hospital in Indondesia. The study was at low risk of bias for all domains with the exception of selective reporting, for which it was unclear. Women in the intervention group received calcium (800 mg) plus N-acetylcysteine (200 mg), Cu (2 mg), Zn (15 mg), Mn (0.5 mg) and selenium (100 mcg) and vitamins A (1000 IU), B6 (2.2 mg), B12 (2.2 mcg), C (200 mg), and E (400 IU) versus the placebo control group of women who received similar looking tablets containing iron and folic acid. Both groups received iron (30 mg) and folic acid (400 mcg). Tablets were taken twice daily from eight to 12 weeks of gestation and then throughout pregnancy.The included study found that calcium supplementation plus antioxidants and other supplements may slightly reduce pre-eclampsia (gestational hypertension and proteinuria) (risk ratio (RR) 0.24, 95% confidence interval (CI) 0.06 to 1.01; low-quality evidence), but this is uncertain due to wide confidence intervals just crossing the line of no effect, and small sample size. It appears that earlypregnancy loss before 20 weeks' gestation (RR 0.06, 95% CI 0.00 to 1.04; moderate-quality evidence) may be slightly reduced by calcium plus antioxidants and other supplements, but this outcome also has wide confidence intervals, which just cross the line of no effect. Very few events were reported under the composite outcome, severe maternal morbidity and mortality index and no clear difference was seen between groups (RR 0.36, 95% CI 0.04 to 3.23; low

  15. Adsorption and release of amino acids mixture onto apatitic calcium phosphates analogous to bone mineral

    NASA Astrophysics Data System (ADS)

    El Rhilassi, A.; Mourabet, M.; El Boujaady, H.; Bennani-Ziatni, M.; Hamri, R. El; Taitai, A.

    2012-10-01

    Study focused on the interaction of adsorbate with poorly crystalline apatitic calcium phosphates analogous to bone mineral. Calcium phosphates prepared in water-ethanol medium at physiological temperature (37 °C) and neutral pH, their Ca/P ratio was between 1.33 and 1.67. Adsorbate used in this paper takes the mixture form of two essential amino acids L-lysine and DL-leucine which have respectively a character hydrophilic and hydrophobic. Adsorption and release are investigated experimentally; they are dependent on the phosphate type and on the nature of adsorbate L-lysine, DL-leucine and their mixture. Adsorption of mixture of amino acids on the apatitic calcium phosphates is influenced by the competition between the two amino acids: L-lysine and DL-leucine which exist in the medium reaction. The adsorption kinetics is very fast while the release kinetics is slow. The chemical composition of apatite has an influence on both adsorption and release. The interactions adsorbate-adsorbent are electrostatic type. Adsorption and release reactions of the amino acid mixture are explained by the existence of the hydrated surface layer of calcium phosphate apatite. The charged sbnd COOsbnd and sbnd NH3+ of adsorbates are the strongest groups that interact with the surface of apatites, the adsorption is mainly due to the electrostatic interaction between the groups sbnd COOsbnd of amino acids and calcium Ca2+ ions of the apatite. Comparative study of interactions between adsorbates (L-lysine, DL-leucine and their mixture) and apatitic calcium phosphates is carried out in vitro by using UV-vis and infrared spectroscopy IR techniques.

  16. BENCH-SCALE EVALUATION OF CALCIUM SORBENTS FOR ACID GAS EMISSION CONTROL

    EPA Science Inventory

    Calcium sorbents for acid gas emission control were evaluated for effectiveness in removing SO2/HCl and SO2/NO from simulated incinerator and boiler flue gases. All tests were conducted in a bench-scale reactor (fixed-bed) simulating fabric filter conditions in an acid gas remova...

  17. PRESENILIN-NULL CELLS HAVE ALTERED TWO-PORE CALCIUM CHANNEL EXPRESSION AND LYSOSOMAL CALCIUM; IMPLICATIONS FOR LYSOSOMAL FUNCTION

    PubMed Central

    Kayala, Kara M Neely; Dickinson, George D; Minassian, Anet; Walls, Ken C; Green, Kim N; LaFerla, Frank M

    2012-01-01

    Presenilins are necessary for calcium homeostasis and also for efficient proteolysis through the autophagy/lysosome system. Presenilin regulates both endoplasmic reticulum calcium stores and autophagic proteolysis in a γ-secretase independent fashion. The endo-lysosome system can also act as a calcium store, with calcium efflux channels being recently identified as two-pore channels 1 and 2. Here we investigated lysosomal calcium content and the channels that mediate calcium release from these acidic stores in presenilin knockout cells. We report that presenilin loss leads to a lower total lysosomal calcium store despite the buildup of lysosomes found in these cells. Additionally, we find alterations in two-pore calcium channel protein expression, with loss of presenilin preventing the formation of a high molecular weight species of TPC1 and TPC2. Finally, we find that treatments that disturb lysosomal calcium release lead to a reduction in autophagy function yet lysosomal inhibitors do not alter two-pore calcium channel expression. These data indicate that alterations in lysosomal calcium in the absence of presenilins might be leading to disruptions in autophagy. PMID:23103503

  18. The role of calcium intake in preventing bone fragility, hypertension, and certain cancers.

    PubMed

    Barger-Lux, M J; Heaney, R P

    1994-08-01

    This paper examines the evidence that connects calcium intake and vitamin D status to bone fragility, hypertension, colon cancer, and breast cancer. Human calcium physiology, with an intestinal absorptive barrier and inefficient conservation, reflects the abundance of calcium in the primordial human food supply. The calcium intake of stone-age adults is estimated at 50 to 75 mmol/d, three to five times the median calcium intake of present-day U.S. adults. Long-term calcium restriction and/or insufficient vitamin D may promote the development of bone fragility, high blood pressure, colon cancer, and breast cancer in susceptible individuals. Conversely, improvement in calcium intake and/or in vitamin D status may help to prevent these serious health problems. At least 12 intervention studies have established the skeletal benefit of increased calcium intake among women in the late postmenopause. Other reports suggest that adequate calcium may protect against salt-sensitive and pregnancy-associated hypertension. High intakes of both dietary calcium and vitamin D are associated with reduced development of precancerous changes in colonic mucosa. Preliminary findings also suggest that vitamin D has a protective effect against breast cancer.

  19. Amino Acid Medical Foods Provide a High Dietary Acid Load and Increase Urinary Excretion of Renal Net Acid, Calcium, and Magnesium Compared with Glycomacropeptide Medical Foods in Phenylketonuria

    PubMed Central

    Stroup, Bridget M.; Sawin, Emily A.; Murali, Sangita G.; Binkley, Neil; Hansen, Karen E.

    2017-01-01

    Background. Skeletal fragility is a complication of phenylketonuria (PKU). A diet containing amino acids compared with glycomacropeptide reduces bone size and strength in mice. Objective. We tested the hypothesis that amino acid medical foods (AA-MF) provide a high dietary acid load, subsequently increasing urinary excretion of renal net acid, calcium, and magnesium, compared to glycomacropeptide medical foods (GMP-MF). Design. In a crossover design, 8 participants with PKU (16–35 y) provided food records and 24-hr urine samples after consuming a low-Phe diet in combination with AA-MF and GMP-MF for 1–3 wks. We calculated potential renal acid load (PRAL) of AA-MF and GMP-MF and determined bone mineral density (BMD) measurements using dual X-ray absorptiometry. Results. AA-MF provided 1.5–2.5-fold higher PRAL and resulted in 3-fold greater renal net acid excretion compared to GMP-MF (p = 0.002). Dietary protein, calcium, and magnesium intake were similar. GMP-MF significantly reduced urinary excretion of calcium by 40% (p = 0.012) and magnesium by 30% (p = 0.029). Two participants had low BMD-for-age and trabecular bone scores, indicating microarchitectural degradation. Urinary calcium with AA-MF negatively correlated with L1–L4 BMD. Conclusion. Compared to GMP-MF, AA-MF increase dietary acid load, subsequently increasing urinary calcium and magnesium excretion, and likely contributing to skeletal fragility in PKU. The trial was registered at clinicaltrials.gov as NCT01428258. PMID:28546877

  20. Intensified Vegetation Water Use due to Soil Calcium Leaching under Acid Deposition

    NASA Astrophysics Data System (ADS)

    Lanning, M.; Wang, L.; Scanlon, T. M.; Vadeboncoeur, M. A.; Adams, M. B.; Epstein, H. E.; Druckenbrod, D.

    2017-12-01

    Despite the important role vegetation plays in the global water cycle, the exact controls of vegetation water use, especially the role of soil biogeochemistry, remain elusive. Nitrate and sulfate deposition from fossil fuel burning has caused significant soil acidification, leading to the leaching of soil base cations. From a physiological perspective, plants require various soil cations as signaling and regulatory ions as well as integral parts of structural molecules; a depletion of soil cations can cause reduced productivity and abnormal responses to environmental change. A deficiency in calcium could also potentially prolong stomatal opening, leading to increased transpiration until enough calcium had been acquired to stimulate stomatal closure. Based on the plant physiology and the nature of acidic deposition, we hypothesize that depletion of the soil calcium supply, induced by acid deposition, would intensify vegetation water use at the watershed scale. We tested this hypothesis by analyzing a long-term and unique data set (1989-2012) of soil lysimeter data along with stream flow and evapotranspiration data at the Fernow Experimental Forest. We show that depletion of soil calcium by acid deposition can intensify vegetation water use ( 10% increase in evapotranspiration and depletion in soil water) for the first time. These results are critical to understanding future water availability, biogeochemical cycles, and surficial energy flux and may help reduce uncertainties in terrestrial biosphere models.

  1. Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

    PubMed Central

    Jiang, Wenge; Pacella, Michael S.; Athanasiadou, Dimitra; Nelea, Valentin; Vali, Hojatollah; Hazen, Robert M.; Gray, Jeffrey J.; McKee, Marc D.

    2017-01-01

    Chirality is ubiquitous in biology, including in biomineralization, where it is found in many hardened structures of invertebrate marine and terrestrial organisms (for example, spiralling gastropod shells). Here we show that chiral, hierarchically organized architectures for calcium carbonate (vaterite) can be controlled simply by adding chiral acidic amino acids (Asp and Glu). Chiral, vaterite toroidal suprastructure having a ‘right-handed' (counterclockwise) spiralling morphology is induced by L-enantiomers of Asp and Glu, whereas ‘left-handed' (clockwise) morphology is induced by D-enantiomers, and sequentially switching between amino-acid enantiomers causes a switch in chirality. Nanoparticle tilting after binding of chiral amino acids is proposed as a chiral growth mechanism, where a ‘mother' subunit nanoparticle spawns a slightly tilted, consequential ‘daughter' nanoparticle, which by amplification over various length scales creates oriented mineral platelets and chiral vaterite suprastructures. These findings suggest a molecular mechanism for how biomineralization-related enantiomers might exert hierarchical control to form extended chiral suprastructures. PMID:28406143

  2. Prevention of nutritional rickets in Nigerian children with dietary calcium supplementation.

    PubMed

    Thacher, Tom D; Fischer, Philip R; Isichei, Christian O; Zoakah, Ayuba I; Pettifor, John M

    2012-05-01

    Nutritional rickets in Nigerian children usually results from dietary calcium insufficiency. Typical dietary calcium intakes in African children are about 200mg daily (approximately 20-28% of US RDAs for age). We sought to determine if rickets could be prevented with supplemental calcium or with an indigenous food rich in calcium. We enrolled Nigerian children aged 12 to 18months from three urban communities. Two communities were assigned calcium, either as calcium carbonate (400mg) or ground fish (529±109mg) daily, while children in all three communities received vitamin A (2500IU) daily as placebo. Serum markers of mineral homeostasis and forearm bone density (pDEXA) were measured and radiographs were obtained at enrollment and after 18months of supplementation. The overall prevalence of radiographic rickets at baseline was 1.2% and of vitamin D deficiency [serum 25(OH)D<12ng/ml] 5.4%. Of 647 children enrolled, 390 completed the 18-month follow-up. Rickets developed in 1, 1, and 2 children assigned to the calcium tablet, ground fish, and control groups, respectively (approximate incidence 6.4/1000 children/year between 1 and 3years of age). Children who developed rickets in the calcium-supplemented groups had less than 50% adherence. Compared with the group that received no calcium supplementation, the groups that received calcium had a greater increase in areal bone density of the distal and proximal 1/3 radius and ulna over time (P<0.04). We conclude that calcium supplementation increased areal bone density at the radius and ulna, but a larger sample size would be required to determine its effect on the incidence of rickets. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. A hybrid composite system of biphasic calcium phosphate granules loaded with hyaluronic acid-gelatin hydrogel for bone regeneration.

    PubMed

    Faruq, Omar; Kim, Boram; Padalhin, Andrew R; Lee, Gun Hee; Lee, Byong-Taek

    2017-10-01

    An ideal bone substitute should be made of biocompatible materials that mimic the structure, characteristics, and functions of natural bone. Many researchers have worked on the fabrication of different bone scaffold systems including ceramic-polymer hybrid system. In the present study, we incorporated hyaluronic acid-gelatin hydrogel to micro-channeled biphasic calcium phosphate granules as a carrier to improve cell attachment and proliferation through highly interconnected porous structure. This hybrid system is composed of ceramic biphasic calcium phosphate granules measuring 1 mm in diameter with seven holes and hyaluronic acid-gelatin hydrogel. This combination of biphasic calcium phosphate and hyaluronic acid-gelatin retained suitable characteristics for bone regeneration. The resulting scaffold had a porosity of 56% with a suitable pore sizes. The mechanical strength of biphasic calcium phosphate granule increased after loading hyaluronic acid-gelatin from 4.26 ± 0.43 to 6.57 ± 0.25 MPa, which is highly recommended for cancellous bone substitution. Swelling and degradation rates decreased in the hybrid scaffold compared to hydrogel due to the presence of granules in hybrid scaffold. In vitro cytocompatibility studies were observed by preosteoblasts (MC3T3-E1) cell line and the result revealed that biphasic calcium phosphate/hyaluronic acid-gelatin significantly increased cell growth and proliferation compared to biphasic calcium phosphate granules. Analysis of micro-computed tomography data and stained tissue sections from the implanted samples showed that the hybrid scaffold had good osseointegration and better bone formation in the scaffold one and two months postimplantation. Histological section confirmed the formation of dense collagenous tissue and new bone in biphasic calcium phosphate/hyaluronic acid-gelatin scaffolds at two months. Our study demonstrated that such hybrid biphasic calcium phosphate/hyaluronic acid-gelatin scaffold is a

  4. Effect of QMix, peracetic acid and ethylenediaminetetraacetic acid on calcium loss and microhardness of root dentine

    PubMed Central

    Taneja, Sonali; Kumari, Manju; Anand, Surbhi

    2014-01-01

    Objectives: The objective of this in vitro study was to assess the effect of different chelating agents on the calcium loss and its subsequent effect on the microhardness of the root dentin. Materials and Methods: Ten single rooted lower premolars were selected. The teeth were decoronated and thick transverse sections of 2 mm were obtained from the coronal third of the root. Each section was then divided into four quarters, each part constituting a sample specimen from the same tooth for each group. The treatment groups were: Group 1 (Control): 5% Sodium hypochlorite (NaOCl) for 5 min + distilled water for 5 min; Group 2: 5% NaOCl for 5 min + 17% ethylenediaminetetraacetic acid (EDTA) for 5 min; Group 3: 5% NaOCl for 5 min + 2.25% Peracetic acid (PAA) for 5 min and Group 4: 5% NaOCl for 5 min + QMix for 5 min respectively. The calcium loss of the samples was evaluated using the Atomic Absorption Spectrophotometer followed by determination of their microhardness using Vickers Hardness Tester. Data was analyzed using one-way ANOVA, Post hoc Tukey test and Pearson correlation. Results: The maximum calcium loss and minimum microhardness was observed in Group 3 followed by Group 2, Group 4 and Group 1. There was a statistically significant difference between all the groups except between Groups 2 and 4. Conclusions: Irrigation with NaOCl + 2.25% PAA caused the maximum calcium loss from root dentin and reduced microhardness. A negative correlation existed between the calcium loss and reduction in the microhardness of root dentin. PMID:24778513

  5. Poly (vinylsulfonic acid) assisted synthesis of aqueous solution stable vaterite calcium carbonate nanoparticles.

    PubMed

    Nagaraja, Ashvin T; Pradhan, Sulolit; McShane, Michael J

    2014-03-15

    Calcium carbonate nanoparticles of the vaterite polymorph were synthesized by combining CaCl2 and Na2CO3 in the presence of poly (vinylsulfonic acid) (PVSA). By studying the important experimental parameters we found that controlling PVSA concentration, reaction temperature, and order of reagent addition the particle size, monodispersity, and surface charge can be controlled. By increasing PVSA concentration or by decreasing temperature CCNPs with an average size from ≈150 to 500 nm could be produced. We believe the incorporation of PVSA into the reaction plays a dual role to (1) slow down the nucleation rate by sequestering calcium and to (2) stabilize the resulting CCNPs as the vaterite polymorph, preventing surface calcification or aggregation into microparticles. The obtained vaterite nanoparticles were found to maintain their crystal structure and surface charge after storage in aqueous buffer for at least 5 months. The aqueous stable vaterite nanoparticles could be a useful platform for the encapsulation of a large variety of biomolecules for drug delivery or as a sacrificial template toward capsule formation for biosensor applications. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Phytoplankton calcification as an effective mechanism to prevent cellular calcium poisoning

    NASA Astrophysics Data System (ADS)

    Müller, M. N.; Ramos, J. Barcelos e.; Schulz, K. G.; Riebesell, U.; Kaźmierczak, J.; Gallo, F.; Mackinder, L.; Li, Y.; Nesterenko, P. N.; Trull, T. W.; Hallegraeff, G. M.

    2015-08-01

    Marine phytoplankton has developed the remarkable ability to tightly regulate the concentration of free calcium ions in the intracellular cytosol at a level of ~ 0.1 μmol L-1 in the presence of seawater Ca2+ concentrations of 10 mmol L-1. The low cytosolic calcium ion concentration is of utmost importance for proper cell signalling function. While the regulatory mechanisms responsible for the tight control of intracellular Ca2+ concentration are not completely understood, phytoplankton taxonomic groups appear to have evolved different strategies, which may affect their ability to cope with changes in seawater Ca2+ concentrations in their environment on geological time scales. For example, the Cretaceous (145 to 66 Ma ago), an era known for the high abundance of coccolithophores and the production of enormous calcium carbonate deposits, exhibited seawater calcium concentrations up to four times present-day levels. We show that calcifying coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica and Coccolithus braarudii) are able to maintain their relative fitness (in terms of growth rate and photosynthesis) at simulated Cretaceous seawater calcium concentrations, whereas these rates are severely reduced under these conditions in some non-calcareous phytoplankton species (Chaetoceros sp., Ceratoneis closterium and Heterosigma akashiwo). Most notably, this also applies to a non-calcifying strain of E. huxleyi which displays a calcium-sensitivity similar to the non-calcareous species. We hypothesize that the process of calcification in coccolithophores provides an efficient mechanism to prevent cellular calcium poisoning and thereby offered a potential key evolutionary advantage, responsible for the proliferation of coccolithophores during times of high seawater calcium concentrations.

  7. Prevention of hip fractures by correcting calcium and vitamin D insufficiencies in elderly people.

    PubMed

    Meunier, P

    1996-01-01

    For a 50-year old caucasian woman today, the risk of a hip fracture over her remaining lifetime is about 17%. Tomorrow the situation will clearly be worse because the continual increase in life expectancy will cause a 3-fold rise in worldwide fracture incidence over the next 60 years, particularly in women, but also in men. In addition, a secular increase in the incidence of hip fractures in individuals of the same age has been noted in both sexes by several investigators, and the cost of hip fractures is expected to dramatically increase in the next decades. Consequently, preventive strategies are urgently required. A great deal has been learned in recent years about the risk factors for hip fracture, the pathophysiology of this fracture, and the prediction of fracture risk, particularly through bone mass measurements on the hip and biochemical evaluations of parathyroid and vitamin D status. The two main determinants of hip fractures are falls and bone loss leading to an intrinsic femoral fragility. A substantial femoral bone loss continues throughout the old age, with a continuous and exponential increase in the risk of hip fracture, and any reduction or arrest of this loss will induce an important reduction in the incidence of hip fractures. A preventive effect on the risk of hip fracture may be partly achieved by using long term estrogen replacement therapy after menopause, but also by using vitamin D and calcium supplements for a late prevention in elderly people. Vitamin D insufficiency and deficit in calcium intake are very common in elderly people living either in institutions or at home, particularly in Europe where dairy products are not fortified with vitamin D. The cumulative response to this deficit in calcium intake and low vitamin D status is a negative calcium balance which stimulates parathyroid hormone secretion. In 300 residents of nursing homes, we recently found a significant negative correlation between serum 25 OHD and log serum PTH after

  8. Assay of calcium borogluconate veterinary medicines for calcium gluconate, boric acid, phosphorus, and magnesium by using inductively coupled plasma emission spectrometry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lyons, D.J.; Spann, K.P.

    1985-03-01

    An inductively coupled plasma spectrometric method is described for the determination of 4 elements (Ca, B, P, and Mg) in calcium borogluconate veterinary medicines. Samples are diluted, acidified, and sprayed directly into the plasma. Reproducibility relative confidence intervals for a single sample assay are +/- 1.4% (calcium), +/- 1.8% (boron), +/- 2.6% (phosphorus), and +/- 1.4% (magnesium). The total element concentrations for each of 4 elements compared favorably with concentrations determined by alternative methods. Formulation estimates of levels of calcium gluconate, boric acid, phosphorus, and magnesium salts can be made from the analytical data.

  9. A Prospective Study on Role of Supplemental Oral Calcium and Vitamin D in Prevention of Postthyroidectomy Hypocalcemia

    PubMed Central

    Ravikumar, Krishnan; Sadacharan, Dhalapathy; Muthukumar, Sankaran; Sundarram, Thalavai; Periyasamy, Selladurai; Suresh, R. V.

    2017-01-01

    Background: Postoperative transient hypocalcemia is sequelae of total thyroidectomy (TT), which is observed in up to 50% of patients. Routine oral calcium and Vitamin D supplementation have been proposed to prevent symptomatic hypocalcemia preventing morbidity and facilitating early discharge. Patients and Methods: A total of 208 patients with nontoxic benign thyroid disorders, undergoing TT, were serially randomized into four groups: Group A (no supplements were given), Group B (oral calcium – 2 g/day given), Group C (calcium and calcitriol – 1 mcg/day are given), and Group D (calcium, calcitriol, and cholecalciferol – 60,000 IU/day are given). Patients were monitored for clinical and biochemical hypocalcemia (serum calcium, [Sr. Ca] <8 mg/dl), along with serum intact parathormone (Sr. PTH) and magnesium 6 h after surgery and Sr. Ca every 24 h. Intravenous (IV) calcium infusion was started, if any of the above four groups exhibit frank hypocalcemia. Patients are followed up with Sr. Ca and Sr. PTH at 3 and 6 months. Results: All groups were age and sex matched. Hypocalcemia was observed in 72/208 (34.61%) cases. Incidence of hypocalcemia was higher in Group A (57.69%) and Group B (50%) compared to Group C (15.38%) and Group D (15.38%). Hypocalcemia necessitating IV calcium occurred in 31/208 (14.90%) patients. IV calcium requirement exceeded in Group A (26.92%) and Group B (23.07%) compared to Group C (5.76%) and Group D (3.84%). There was no statistical difference in basal levels of serum Vitamin D, calcium, magnesium, intact PTH, and 6 h after surgery. Permanent hypoparathyroidism developed in five patients on follow-up. Conclusion: Routine postoperative supplementation of oral calcium and Vitamin D will help in the prevention of postthyroidectomy transient hypocalcemia significantly. Preoperative Vitamin D levels do not predict postoperative hypocalcemia. PMID:28670529

  10. A Prospective Study on Role of Supplemental Oral Calcium and Vitamin D in Prevention of Postthyroidectomy Hypocalcemia.

    PubMed

    Ravikumar, Krishnan; Sadacharan, Dhalapathy; Muthukumar, Sankaran; Sundarram, Thalavai; Periyasamy, Selladurai; Suresh, R V

    2017-01-01

    Postoperative transient hypocalcemia is sequelae of total thyroidectomy (TT), which is observed in up to 50% of patients. Routine oral calcium and Vitamin D supplementation have been proposed to prevent symptomatic hypocalcemia preventing morbidity and facilitating early discharge. A total of 208 patients with nontoxic benign thyroid disorders, undergoing TT, were serially randomized into four groups: Group A (no supplements were given), Group B (oral calcium - 2 g/day given), Group C (calcium and calcitriol - 1 mcg/day are given), and Group D (calcium, calcitriol, and cholecalciferol - 60,000 IU/day are given). Patients were monitored for clinical and biochemical hypocalcemia (serum calcium, [Sr. Ca] <8 mg/dl), along with serum intact parathormone (Sr. PTH) and magnesium 6 h after surgery and Sr. Ca every 24 h. Intravenous (IV) calcium infusion was started, if any of the above four groups exhibit frank hypocalcemia. Patients are followed up with Sr. Ca and Sr. PTH at 3 and 6 months. All groups were age and sex matched. Hypocalcemia was observed in 72/208 (34.61%) cases. Incidence of hypocalcemia was higher in Group A (57.69%) and Group B (50%) compared to Group C (15.38%) and Group D (15.38%). Hypocalcemia necessitating IV calcium occurred in 31/208 (14.90%) patients. IV calcium requirement exceeded in Group A (26.92%) and Group B (23.07%) compared to Group C (5.76%) and Group D (3.84%). There was no statistical difference in basal levels of serum Vitamin D, calcium, magnesium, intact PTH, and 6 h after surgery. Permanent hypoparathyroidism developed in five patients on follow-up. Routine postoperative supplementation of oral calcium and Vitamin D will help in the prevention of postthyroidectomy transient hypocalcemia significantly. Preoperative Vitamin D levels do not predict postoperative hypocalcemia.

  11. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems.

    PubMed

    Hofmeyr, G Justus; Lawrie, Theresa A; Atallah, Alvaro N; Duley, Lelia; Torloni, Maria R

    2014-06-24

    Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 March 2013) and contacted study authors for more data where possible. We updated the search in May 2014 and added the results to the 'Awaiting Classification' section of the review. Randomised controlled trials (RCTs) comparing high-dose (at least 1 g daily of calcium) or low-dose calcium supplementation during pregnancy with placebo or no calcium. We assessed eligibility and trial quality, extracted and double-entered data. High-dose calcium supplementation (≥1 g/day)We included 14 studies in the review, however one study contributed no data. We included 13 high-quality studies in our meta-analyses (15,730 women). The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a significant reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65; I² = 70%). The effect was greatest for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) and women at high risk of pre-eclampsia (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42; I² = 0%). These data should be interpreted with caution because of the possibility of small-study effect or publication bias.The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97; I² = 0%). Maternal deaths were not significantly different (one trial of 8312 women: calcium

  12. Interactions of calcium and fulvic acid at the goethite-water interface

    NASA Astrophysics Data System (ADS)

    Weng, Li Ping; Koopal, Luuk K.; Hiemstra, Tjisse; Meeussen, Johannes C. L.; Van Riemsdijk, Willem H.

    2005-01-01

    Interactions of calcium and fulvic acid (Strichen ) with the surface of goethite were studied with batch and titration experiments. The mutual influence of the interactions on the adsorption of fulvic acid, calcium ions and protons were examined. Adsorption of the fulvic acid to goethite decreased with increase in pH (pH range 3-11). Addition of Ca (1.0 mM) at intermediate and high pH significantly enhanced the adsorption of fulvic acid. Compared to the adsorption to pure goethite, the presence of fulvic acid enhanced the adsorption of Ca significantly. In comparison to the simple linear sum of Ca bound to fulvic acid and goethite, the interactions between goethite and fulvic acid led to a reduced adsorption of Ca at low pH and an enhanced adsorption at high pH. With the adsorption of fulvic acid, protons were released at low pH and coadsorbed at high pH. When Ca was added, fewer protons were released at low pH and fewer coadsorbed at high pH. The experimental results can be adequately described using a surface complexation model, the Ligand and Charge Distribution (LCD) model, in which the CD-MUSIC model for ion adsorption to mineral oxides and the NICA model for ion binding to humics are integrated. In the model calculations, adequate descriptions of the ternary system data (Ca-fulvic acid-goethite) were obtained with parameters derived from three binary systems (fulvic acid-goethite, Ca-goethite and Ca-fulvic acid) without further adjustment. The model calculations suggest that the interactions between Ca and fulvic acid at the surface of goethite are mainly due to the electrostatic effects.

  13. Wood decay fungi restore essential calcium to acidic soils in northern New England

    Treesearch

    Walter C. Shortle; Kevin T. Smith

    2015-01-01

    The depletion of root-available calcium in northern forests soils exposed to decades of increased acid deposition adversely affects forest health and productivity. Laboratory studies indicated the potential of wood-decay fungi to restore lost calcium to the rooting zone of trees. This study reports changes in concentrations of Ca, Mg, and K during decay of sapwood of...

  14. Prolonged exposure to 1,25(OH)2D3 and high ionized calcium induces FGF-23 production in intestinal epithelium-like Caco-2 monolayer: A local negative feedback for preventing excessive calcium transport.

    PubMed

    Rodrat, Mayuree; Wongdee, Kannikar; Panupinthu, Nattapon; Thongbunchoo, Jirawan; Teerapornpuntakit, Jarinthorn; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

    2018-02-15

    Overdose of oral calcium supplement and excessive intestinal calcium absorption can contribute pathophysiological conditions, e.g., nephrolithiasis, vascular calcification, dementia, and cardiovascular accident. Since our previous investigation has indicated that fibroblast growth factor (FGF)-23 could abolish the 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ]-enhanced calcium absorption, we further hypothesized that FGF-23 produced locally in the enterocytes might be part of a local negative feedback loop to regulate calcium absorption. Herein, 1,25(OH) 2 D 3 was found to enhance the transcellular calcium transport across the epithelium-like Caco-2 monolayer, and this stimulatory effect was diminished by preceding prolonged exposure to high-dose 1,25(OH) 2 D 3 or high concentration of apical ionized calcium. Pretreatment with a neutralizing antibody for FGF-23 prevented this negative feedback regulation of calcium hyperabsorption induced by 1,25(OH) 2 D 3 . FGF-23 exposure completely abolished the 1,25(OH) 2 D 3 -enhanced calcium transport. Western blot analysis revealed that FGF-23 expression was upregulated in a dose-dependent manner by 1,25(OH) 2 D 3 or apical calcium exposure. Finally, calcium-sensing receptor (CaSR) inhibitors were found to prevent the apical calcium-induced suppression of calcium transport. In conclusion, prolonged exposure to high apical calcium and calcium hyperabsorption were sensed by CaSR, which, in turn, increased FGF-23 expression to suppress calcium transport. This local negative feedback loop can help prevent unnecessary calcium uptake and its detrimental consequences. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Supplementing a low-protein diet with dibasic amino acids increases urinary calcium excretion in young women.

    PubMed

    Bihuniak, Jessica D; Sullivan, Rebecca R; Simpson, Christine A; Caseria, Donna M; Huedo-Medina, Tania B; O'Brien, Kimberly O; Kerstetter, Jane E; Insogna, Karl L

    2014-03-01

    Increasing dietary protein within a physiologic range stimulates intestinal calcium absorption, but it is not known if specific amino acids or dietary protein as a whole are responsible for this effect. Therefore, we selectively supplemented a low-protein (0.7 g/kg) diet with either the calcium-sensing receptor-activating amino acids (CaSR-AAAs) L-tryptophan, L-phenylalanine, and L-histidine, or the dibasic amino acids (DAAs) L-arginine and L-lysine, to achieve intakes comparable to the content of a high-protein diet (2.1 g/kg) and measured intestinal calcium absorption. Fourteen young women took part in a placebo-controlled, double-blind, crossover feeding trial in which each participant ingested a 6-d low-protein diet supplemented with CaSR-AAAs, DAAs, or methylcellulose capsules (control) after an 11-d adjustment period. All participants ingested all 3 diets in random order. Intestinal calcium absorption was measured between days 5 and 6 using dual-stable calcium isotopes ((42)Ca, (43)Ca, and (44)Ca). There was no difference in calcium absorption between the diet supplemented with CaSR-AAAs (22.9 ± 2.0%) and the control diet (22.3 ± 1.4%) (P = 0.64). However, calcium absorption tended to be greater during the DAA supplementation period (25.2 ± 1.4%) compared with the control diet period (22.3 ± 1.4%) (P < 0.10). Larger and longer clinical trials are needed to clarify the possible benefit of arginine and lysine on calcium absorption.

  16. Is vaccenic acid (18:1t n-7) associated with an increased incidence of hip fracture? An explanation for the calcium paradox.

    PubMed

    Hamazaki, Kei; Suzuki, Nobuo; Kitamura, Kei-Ichiro; Hattori, Atsuhiko; Nagasawa, Tetsuro; Itomura, Miho; Hamazaki, Tomohito

    2016-06-01

    High calcium intake may increase hip fracture (HF) incidence. This phenomenon, known as the calcium paradox, might be explained by vaccenic acid (18:1t n-7, VA), the highly specific trans fatty acid (TFA) present in dairy products. First, we ecologically investigated the relationship between 18:1 TFA intake and HF incidence using data from 12 to 13 European countries collected before 2000; then we measured the effects of VA and elaidic acid (18:1t n-9, EA) on osteoblasts from goldfish scales (tissues very similar to mammalian bone), with alkaline phosphatase as a marker; and finally we measured the effect of VA on mRNA expression in the scales for the major bone proteins type I collagen and osteocalcin. HF incidence was significantly correlated with 18:1 TFA intake in men (r=0.57) and women (r=0.65). Incubation with 1μmol/L VA and EA for 48h significantly decreased alkaline phosphatase activity by 25% and 21%, respectively. Incubation of scales with 10μmol/L VA for 48h significantly decreased mRNA expression for type I collagen and osteocalcin (by about 50%). In conclusion, VA may be causatively related to HF and could explain the calcium paradox. It may be prudent to reduce 18:1 TFA intake, irrespective of trans positions, to prevent HF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false D-Glucuronic acid, polymer with 6...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

  18. Obtaining and Characterization of Polyolefin-Filled Calcium Carbonate Composites Modified with Stearic Acid

    NASA Astrophysics Data System (ADS)

    Croitoru, C.; Pascu, A.; Roata, I. C.; Stanciu, E. M.

    2017-06-01

    In order to obtain high performance calcium carbonate-reinforced HDPE and PP composites, the dispersibility and compatibility of the inorganic phase in the polymer has been achieved through surface treatment of the amorphous calcium carbonate filler with stearic acid. The surface coating of the inorganic phase has been proved by XRD and FTIR spectroscopy, through forming of an intermediate layer of calcium stearate which acts as a surfactant, efficient in providing an optimum compatibility with the dominatingly hydrophobic polymer matrix, as determined from the structural information obtained through samples cross-sections analysing.

  19. Treatment and prevention of kidney stones: an update.

    PubMed

    Frassetto, Lynda; Kohlstadt, Ingrid

    2011-12-01

    The incidence of nephrolithiasis (kidney stones) is rising worldwide, especially in women and with increasing age. Kidney stones are associated with chronic kidney disease. Preventing recurrence is largely specific to the type of stone (e.g., calcium oxalate, calcium phosphate, cystine, struvite [magnesium ammonium phosphate]), and uric acid stones); however, even when the stone cannot be retrieved, urine pH and 24-hour urine assessment provide information about stone-forming factors that can guide prevention. Medications, such as protease inhibitors, antibiotics, and some diuretics, increase the risk of some types of kidney stones, and patients should be counseled about the risks of using these medications. Managing diet, medication use, and nutrient intake can help prevent the formation of kidney stones. Obesity increases the risk of kidney stones. However, weight loss could undermine prevention of kidney stones if associated with a high animal protein intake, laxative abuse, rapid loss of lean tissue, or poor hydration. For prevention of calcium oxalate, cystine, and uric acid stones, urine should be alkalinized by eating a diet high in fruits and vegetables, taking supplemental or prescription citrate, or drinking alkaline mineral waters. For prevention of calcium phosphate and struvite stones, urine should be acidified; cranberry juice or betaine can lower urine pH. Antispasmodic medications, ureteroscopy, and metabolic testing are increasingly being used to augment fluid and pain medications in the acute management of kidney stones.

  20. Effects of feeding fatty acid calcium and the interaction of forage quality on production performance and biochemical indexes in early lactation cow.

    PubMed

    Hu, Z Y; Yin, Z Y; Lin, X Y; Yan, Z G; Wang, Z H

    2015-10-01

    Multiparous early lactation Holstein cows (n = 16) were used in a randomized complete block design to determine the effects of feeding fatty acid calcium and the interaction of forage quality on production performance and biochemical indexes in early lactation cow. Treatments were as follows: (i) feeding low-quality forage without supplying fatty acid calcium (Diet A), (ii) feeding low-quality forage with supplying 400 g fatty acid calcium (Diet B), (iii) feeding high-quality forage without supplying fatty acid calcium (Diet C) and (iv) feeding high-quality forage with supplying 400 g fatty acid calcium. This experiment consisted 30 days. The milk and blood samples were collected in the last day of the trail. Intakes were recorded in the last 2 days of the trail. Supplementation of fatty acid calcium decreased significantly dry matter intake (DMI) (p < 0.01). Addition fatty acid calcium decreased milk protein percentage (p < 0.01) and milk SNF percentage (p < 0.01), but increased MUN (p < 0.05). Supplemented fatty acid decreased concentration of blood BHBA (p < 0.05), but increased TG, NEFA, glucagon, GLP-1, CCK, leptin, ApoA-IV, serotonin and MSH concentration in blood, the CCK concentration and feed intake showed a significant negative correlation (p < 0.05). Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

  1. Abscisic acid triggers whole-plant and fruit-specific mechanisms to increase fruit calcium uptake and prevent blossom end rot development in tomato fruit.

    PubMed

    de Freitas, Sergio Tonetto; Shackel, Kenneth A; Mitcham, Elizabeth J

    2011-05-01

    Calcium (Ca) uptake into fruit and leaves is dependent on xylemic water movement, and hence presumably driven by transpiration and growth. High leaf transpiration is thought to restrict Ca movement to low-transpiring tomato fruit, which may increase fruit susceptibility to the Ca-deficiency disorder, blossom end rot (BER). The objective of this study was to analyse the effect of reduced leaf transpiration in abscisic acid (ABA)-treated plants on fruit and leaf Ca uptake and BER development. Tomato cultivars Ace 55 (Vf) and AB2 were grown in a greenhouse environment under Ca-deficit conditions and plants were treated weekly after pollination with water (control) or 500 mg l(-1) ABA. BER incidence was completely prevented in the ABA-treated plants and reached values of 30-45% in the water-treated controls. ABA-treated plants had higher stem water potential, lower leaf stomatal conductance, and lower whole-plant water loss than water-treated plants. ABA treatment increased total tissue and apoplastic water-soluble Ca concentrations in the fruit, and decreased Ca concentrations in leaves. In ABA-treated plants, fruit had a higher number of Safranin-O-stained xylem vessels at early stages of growth and development. ABA treatment reduced the phloem/xylem ratio of fruit sap uptake. The results indicate that ABA prevents BER development by increasing fruit Ca uptake, possibly by a combination of whole-plant and fruit-specific mechanisms.

  2. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

    NASA Technical Reports Server (NTRS)

    Lee, J. S.; Mulkey, T. J.; Evans, M. L.

    1984-01-01

    Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

  3. Effects of acid deposition on calcium nutrition and health of Southern Appalachian spruce fir forests

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McLaughlin, S.B.; Wullschleger, S.; Stone, A.

    The role of acid deposition in the health of spruce fir forests in the Southern Appalachian Mountains has been investigated by a wide variety of experimental approaches during the past 10 years. These studies have proceeded from initial dendroecological documentation of altered growth patterns of mature trees to increasingly more focused ecophysiological research on the causes and characteristics of changes in system function associated with increased acidic deposition. Field studies across gradients in deposition and soil chemistry have been located on four mountains spanning 85 km of latitude within the Southern Appalachians. The conclusion that calcium nutrition is an importantmore » component regulating health of red spruce in the Southern Appalachians and that acid deposition significantly reduces calcium availability in several ways has emerged as a consistent result from multiple lines or research. These have included analysis of trends in wood chemistry, soil solution chemistry, foliar nutrition, gas exchange physiology, root histochemistry, and controlled laboratory and field studies in which acid deposition and/or calcium nutrition has been manipulated and growth and nutritional status of saplings or mature red spruce trees measured. This earlier research has led us to investigate the broader implications and consequences of calcium deficiency for changing resistance of spruce-fir forests to natural stresses. Current research is exploring possible relationships between altered calcium nutrition and shifts in response of Fraser fir to insect attack by the balsam wooly adelgid. In addition, changes in wood ultrastructural properties in relation to altered wood chemistry is being examined to evaluate its possible role in canopy deterioration, under wind and ice stresses typical of high elevation forests.« less

  4. [Efficacy of oral calcium and/or sodium phosphate in the prevention of parturient paresis in cows].

    PubMed

    Braun, U; Bryce, B; Liesegang, A; Hässig, M; Bleul, U

    2008-07-01

    The goal of this study was to investigate the efficacy of calcium chloride, sodium phosphate or a combination of these two substances administered orally immediately postpartum for the prevention of parturient paresis in cows. Thirty-two cows that had had parturient paresis at the previous calving, and in which serum biochemistry had shown hypocalcaemia and hypophosphataemia, were used in the study. The cows were transferred to the Department of Farm Animals, University of Zurich, five days before their expected due dates. On a randomized trial, the cows were given calcium chloride, sodium phosphate, both substances or no treatment (controls) via a stomach tube immediately postpartum and 12 hours later. The cows were monitored for 96 hours during which time blood was collected on a regular basis for the determination of total calcium, ionized calcium, inorganic phosphorus and magnesium concentrations. Of the 32 cows treated, 19 (59%) had parturient paresis and 13 (41%) did not. The incidence of parturient paresis did not differ significantly among the groups although there was a tendency for a lower incidence in cows treated with both calcium chloride and sodium phosphate. The various treatments had no apparent effect on serum calcium concentration. The concentration of inorganic phosphorus increased significantly in cows treated with sodium phosphate compared with the controls. The results of this study showed that cows treated with both calcium chloride and sodium phosphate orally tended to have a lower incidence of parturient paresis. Further investigation into multiple administrations of oral calcium chloride and sodium phosphate, started before parturition, for the prevention of parturient paresis is required.

  5. Prevention of volatile fatty acids production and limitation of odours from winery wastewaters by denitrification.

    PubMed

    Bories, André; Guillot, Jean-Michel; Sire, Yannick; Couderc, Marie; Lemaire, Sophie-Andréa; Kreim, Virginie; Roux, Jean-Claude

    2007-07-01

    The effect of the addition of nitrate to winery wastewaters to control the formation of VFA in order to prevent odours during storage and treatment was studied in batch bioreactors at different NO(3)/chemical oxygen demand (COD) ratios and at full scale in natural evaporation ponds (2 x 7000 m(2)) by measuring olfactory intensity. In the absence of nitrate, butyric acid (2304 mgL(-1)), acetic acid (1633 mgL(-1)), propionic acid (1558 mgL(-1)), caproic acid (499 mgL(-1)) and valeric acid (298 mgL(-1)) were produced from reconstituted winery wastewater. For a ratio of NO(3)/COD=0.4 gg(-1), caproic and valeric acids were not formed. The production of butyric and propionic acids was reduced by 93.3% and 72.5%, respectively, at a ratio of NO(3)/COD=0.8, and by 97.4% and 100% at a ratio of NO(3)/COD=1.2 gg(-1). Nitrate delayed and decreased butyric acid formation in relation to the oxidoreduction potential. Studies in ponds showed that the addition of concentrated calcium nitrate (NITCAL) to winery wastewaters (3526 m(3)) in a ratio of NO(3)/COD=0.8 inhibited VFA production, with COD elimination (94%) and total nitrate degradation, and no final nitrite accumulation. On the contrary, in ponds not treated with nitrate, malodorous VFA (from propionic to heptanoïc acids) represented up to 60% of the COD. Olfactory intensity measurements in relation to the butanol scale of VFA solutions and the ponds revealed the pervasive role of VFA in the odour of the untreated pond as well as the clear decrease in the intensity and not unpleasant odour of the winery wastewater pond enriched in nitrates. The results obtained at full scale underscored the feasibility and safety of the calcium nitrate treatment as opposed to concentrated nitric acid.

  6. Effects of calcium fertilization and acid mist on calcium concentration and cold tolerance of red spruce needles

    Treesearch

    G. R. Strimbeck; David R. Vann; Arthur H. Johnson

    1996-01-01

    Several studies have shown that exposure to acid mist impairs cold tolerance of red spruce foliage, predisposing it to winter injury, which appears to be a major factor in the decline of montane populations of the species. Other studies have shown increases in calcium (Ca) concentration in canopy throughfall in montane spruce-fir forests, and decreases in foliar Ca...

  7. A Calcium Enterolith in a Patient with Crohn's Disease and Its In Vitro Dissolubility in Citric Acid

    PubMed Central

    Urata, Haruo; Ohmori, Masayasu; Kondo, Yoshitaka; Kawahara, Yoshiro; Okada, Hiroyuki

    2017-01-01

    The microstructure and dissolubility of a calcified enterolith and enterolith pieces removed from a 26-year-old Japanese woman with Crohn's disease were analyzed using scanning electron microscopy and energy dispersive X-ray spectroscopy. The enterolith showed a multilayered structure with fatty acid calcium and magnesium phosphate. The amount of calcium, magnesium, and phosphate decreased after they were immersed in a citric acid solution, suggesting a potential contribution of acidic aqueous solution to elute inorganic substances contained in calcified enteroliths. This is the first study to investigate the in vitro dissolubility of calcified enteroliths induced by citric acid solution. PMID:29082049

  8. Poly(amido amine) and calcium phosphate nanocomposite remineralization of dentin in acidic solution without calcium phosphate ions.

    PubMed

    Liang, Kunneng; Zhou, Han; Weir, Michael D; Bao, Chongyun; Reynolds, Mark A; Zhou, Xuedong; Li, Jiyao; Xu, Hockin H K

    2017-07-01

    Patients with dry mouth often have an acidic oral environment lacking saliva that provides calcium (Ca) and phosphate (P) ions. However, there has been no study on dentin remineralization by placing samples in an acidic solution without Ca and P ions. Previous studies used saliva-like solutions with neutral pH and Ca and P ions. Therefore, the objective of this study was to investigate a novel method of combining poly(amido amine) (PAMAM) with a composite of nanoparticles of amorphous calcium phosphate (NACP) on dentin remineralization in an acidic solution without Ca and P ions for the first time. Demineralized dentin specimens were tested into four groups: (1) dentin control, (2) dentin coated with PAMAM, (3) dentin with NACP nanocomposite, (4) dentin with PAMAM plus NACP composite. Specimens were treated with lactic acid at pH 4 without initial Ca and P ions for 21 days. Acid neutralization and Ca and P ion concentrations were measured. Dentin specimens were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and hardness testing vs. remineralization efficacy. NACP composite had mechanical properties similar to commercial control composites (p>0.1). NACP composite neutralized acid and released Ca and P ions. PAMAM alone failed to induce dentin remineralization. NACP alone achieved mild remineralization and slightly increased dentin hardness at 21days (p>0.1). In contrast, the PAMAM+NACP nanocomposite method in acid solution without initial Ca and P ions greatly remineralized the pre-demineralized dentin, restoring its hardness to approach that of healthy dentin (p>0.1). Dentin remineralization via PAMAM+NACP in pH 4 acid without initial Ca and P ions was demonstrated for the first time, when conventional methods such as PAMAM did not work. The novel PAMAM+NACP nanocomposite method is promising to protect tooth structures, especially for patients with reduced saliva to inhibit caries. Copyright © 2017 The Academy of Dental

  9. Calcium soap from palm fatty acid distillate for ruminant feed: The influence of water temperature

    NASA Astrophysics Data System (ADS)

    Handojo, Lienda A.; Indarto, Antonius; Shofinita, Dian; Meitha, Anggina; Nabila, Rakhmawati; Triharyogi, Harry; Kevin, Leonardus

    2018-03-01

    As the largest palm oil producing country in the world, Indonesia also produces abundant amount of Palm Fatty Acid Distillate (PFAD), a by-product of Crude Palm Oil (CPO) refining process. PFAD can be utilized as the raw material for calcium soap, ruminant feed that is widely used to increase milk yield, as well as to increase the ruminant’s fertility. However, the practice of feeding ruminants with calcium soap has not been practiced in Indonesia, which makes it imperative to develop calcium soap production process from PFAD within the country. This research aimed to study the effect of operating conditions of the saponification reaction using PFAD and CaO as reactants on the quality of the calcium soap obtained. The saponification reaction was carried out by modified fusion method. A range of stoichiometric mole ratios of CaO to PFAD (1.0 to 1.6) and the temperature of water (60-90°C) were studied in this research. An increase in the stoichiometric mole ratio of CaO/PFAD was observed to cause a decrease in the acid value, which indicates an increase in the reaction conversion. In contrast, the temperature of water was found to have little impact on the acid value of the product.

  10. Assessment the levels of tartrate-resistant acid phosphatase (TRAP) on mice fed with eggshell calcium citrate malate.

    PubMed

    Yu, Yiding; Zhang, Mingdi; Lin, Songyi; Wang, Liyan; Liu, Jingbo; Jones, Gregory; Huang, Hsiang-Chi

    2013-07-01

    Optimized conditions were obtained by one-factor-at-a-time test (OFAT) and ternary quadratic regression orthogonal composite design (TQROCD) respectively. By pulse electric fields (PEF) technology, the process of eggshell calcium citrate malate (ESCCM), eggshell calcium citrate (ESCC) and eggshells calcium malate (ESCM) were comprehensive compared. The levels of tartrate-resistant acid phosphatase (TRAP) and the bioavailability on mice fed with eggshell calcium citrate malate (ESCCM) treated by pulsed electric field (PEF) were evaluated. Results showed that the rates of calcium dissolution of the different acids studied can be arranged as ESCCM (7.90 mg/mL)>ESCC (7.12 mg/mL)>ESCM (7.08 mg/mL) from highest to lowest rate of dissolution. At the same dose 133.0 mg kg(-1) d(-1), the levels of TRAP in the ESCCM treatment groups were significantly lower than those in ESCM and ESCC (P<0.05). Bone calcium content in the mice fed with ESCCM was generally higher than fed with ESCM and ESCC. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Preventive effect of a high fluoride toothpaste and arginine-carbonate toothpaste on dentinal tubules exposure followed by acid challenge: a dentine permeability evaluation

    PubMed Central

    2014-01-01

    Background Considering the current high use of high fluoride toothpastes, the aim of the study was to quantify alterations in the root dentine permeability submitted to treatment with a high fluoride toothpaste and 8% arginine, calcium carbonate, sodium monofluorophosphate toothpaste as a preventive treatment for dentinal tubules exposure followed by acid challenge. Methods Thirty-third molars were sectioned below the cementoenamel. The root segments were connected to a hydraulic pressure apparatus to measure dentine permeability after the following sequential steps (n = 10 per group): I) Baseline; II) treatment with phosphoric acid for 30 s (maximum permeability); III) Toothbrushing (1 min) according to the experimental groups (G1- control; G2- 5000 ppm fluoride toothpaste; G3- 8% arginine-calcium carbonate toothpaste); IV) acid challenge for 5 min (orange juice). The data were converted into percentage, considering stage II as 100%. Results The results have shown a statistically significant decreasing on dentine permeability after treatment with toothpaste (Friedman test and Dunn’s post hoc test). Comparison among groups demonstrated a high increasing on dentine permeability when acid challenge was performed after toothbrushing with distilled water (control group) (Kruskal-Wallis and Dunn’s post hoc test). Conclusion The toothpaste treatment may provide sufficient resistance on dentine surface, preventing dentinal tubules exposure after acid challenge. PMID:24958423

  12. Impact of laminar flow velocity of different acids on enamel calcium loss.

    PubMed

    Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

    2013-03-01

    The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

  13. The effect of essential fatty acid deficiency on the stimulation of intestinal calcium transport by 1,25-dihydroxyvitamin D3.

    PubMed

    Kreutter, D; Matsumoto, T; Peckham, R; Zawalich, K; Wen, W H; Zolock, D T; Rasmussen, H

    1983-04-25

    The effect of altering the lipid composition of the brush-border membrane on the ability of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) to stimulate calcium transport across the intestinal mucosa was examined by raising chicks on a vitamin D, essential fatty acid-deficient diet (-DEFAD) and measuring calcium absorption from duodenal sacs in situ and calcium uptake into brush-border membrane vesicles in vitro. Administration of 1,25-(OH)2D3 to -DEFAD and to -D control chicks led to the same increase in calcium transport in situ, whereas calcium transport in isolated brush-border membrane vesicles was not stimulated in the EFAD group, but responded normally in the control group. When the incubation temperature was increased to 34 degrees C, brush-border membrane vesicles from 1,25-(OH)2D3-treated essential fatty acid-deficient (+DE-FAD) chicks accumulated calcium at a faster rate than did vesicles from -DEFAD chicks. There was a marked decrease in the linoleic acid content and an increase in the oleic acid content of both the total lipid extract of the brush-border membrane as well as the phosphatidylcholine and phosphatidylethanolamine fractions, which could explain the temperature sensitivity of the in vitro system. When the diet of the EFAD chicks was supplemented with linoleic acid, the rate of calcium uptake into subsequently isolated vesicles from +DE-FAD chicks correlated with the amount of linoleic acid in the brush-border membranes. These results support the concept that the action of 1,25-(OH)2D3 on membrane lipid turnover and structure plays a critically important role in the 1,25-(OH)2D3-mediated cellular transport responses.

  14. Interactions between red light, abscisic acid, and calcium in gravitropism

    NASA Technical Reports Server (NTRS)

    Leopold, A. C.; LaFavre, A. K.

    1989-01-01

    The effect of red light on orthogravitropism of Merit corn (Zea mays L.) roots has been attributed to its effects on the transduction phase of gravitropism (AC Leopold, SH Wettlaufer [1988] Plant Physiol 87:803-805). In an effort to characterize the orthogravitropic transduction system, comparative experiments have been carried out on the effects of red light, calcium, and abscisic acid (ABA). The red light effect can be completely satisfied with added ABA (100 micromolar) or with osmotic shock, which is presumed to increase endogenous ABA. The decay of the red light effect is closely paralleled by the decay of the ABA effect. ABA and exogenous calcium show strong additive effects when applied to either Merit or a line of corn which does not require red light for orthogravitropism. Measurements of the ABA content show marked increases in endogenous ABA in the growing region of the roots after red light. The interpretation is offered that red light or ABA may serve to increase the cytoplasmic concentrations of calcium, and that this may be an integral part of orthogravitropic transduction.

  15. Prevention and Treatment of Vitamin D and Calcium Deficiency in Children and Adolescents: Indian Academy of Pediatrics (IAP) Guidelines.

    PubMed

    Khadilkar, Anuradha; Khadilkar, Vaman; Chinnappa, Jagdish; Rathi, Narendra; Khadgawat, Rajesh; Balasubramanian, S; Parekh, Bakul; Jog, Pramod

    2017-07-15

    Vitamin D deficiency (VDD) is being increasingly reported from India from all age-groups. Reports suggest that VDD affects all age groups, from neonates to adolescents. Further, habitually low calcium intakes are also reported in Indian children. Given the multiple guidelines, peculiarities of Indian circumstances, changing lifestyles, and lack of fortification, the Indian Academy of Pediatrics (IAP) felt the need for a Practice Guideline for Pediatricians for the prevention and treatment of vitamin D and calcium deficiency in children and adolescents. The 'Guideline for Vitamin D and Calcium in Children' committee was formed by the IAP in September 2016. A consultative committee meeting was held in November 2016 in Mumbai. Evidence from Indian and international studies and other previous published recommendations, which were pertinent to the Indian circumstances, were collated for the preparation of these guidelines. To present a practice guideline for pediatricians for the prevention and treatment of deficiency of vitamin D and calcium in the Indian context. For the prevention of rickets in premature infants, 400 IU of vitamin D and 150-220 mg/kg of calcium, and in neonates, 400 IU of vitamin D and 200 mg of calcium are recommended daily. For prevention of rickets and hypocalcemia in infants (after neonatal period) upto 1 year of age, and from 1-18 years, 400 IU and 600 IU vitamin D/day and 250-500 mg/day and 600-800 mg/day of calcium, respectively, are recommended. For treatment of rickets in premature neonates, infants upto 1 year and from 1-18 years, 1000 IU, 2000 IU and 3000-6000 IU of vitamin D daily, respectively, and elemental calcium of 70-80 mg/kg/day in premature neonates and 500-800 mg daily for all children over that age are recommended. Larger doses of vitamin D may be given from 3 months to 18 years of age as 60,000 IU/week for 6 weeks.

  16. Influence of nutritional status, laboratory parameters and dietary patterns upon urinary acid excretion in calcium stone formers.

    PubMed

    Tessaro, Carolini Zanette Warmling; Ramos, Christiane Ishikawa; Heilberg, Ita Pfeferman

    2018-04-26

    Obesity and Metabolic Syndrome (MS) are associated with low urinary pH and represent risk factors for nephrolithiasis, especially composed by uric acid. Acidogenic diets may also contribute to a reduction of urinary pH. Propensity for calcium oxalate precipitation has been shown to be higher with increasing features of the MS. A retrospective evaluation of anthropometric and body composition parameters, MS criteria and the dietary patterns of overweight and obese calcium stone formers and their impact upon urinary pH and other lithogenic parameters was performed. Data regarding anthropometry, body composition, serum and urinary parameters and 3-days dietary records were obtained from medical records of 102(34M/68F) calcium stone formers. A negative correlation was found between urinary pH, waist circumference and serum uric acid levels (males). The endogenous production of organic acids (OA) was positively correlated with triglycerides levels and number of features of MS (males), and with glucose, uric acid and triglycerides serum levels, and number of features of MS (females). No significant correlations were detected between Net Acid Excretion (NAE) or Potential Renal Acid Load of the diet with any of the assessed parameters. A multivariate analysis showed a negative association between OA and urinary pH. The endogenous production of OA and not an acidogenic diet were found to be independently predictive factors for lower urinary pH levels in calcium stone formers. Hypercalciuric and/or hyperuricosuric patients presented higher OA levels and lower levels of urinary pH.

  17. Aspirin plus calcium supplementation to prevent superimposed preeclampsia: a randomized trial

    PubMed Central

    Souza, E.V.; Torloni, M.R.; Atallah, A.N.; dos Santos, G.M.S.; Kulay, L.; Sass, N.

    2014-01-01

    Preeclampsia is an important cause of maternal and perinatal morbidity and mortality. Previous studies have tested calcium supplementation and aspirin separately to reduce the incidence of preeclampsia but not the effects of combined supplementation. The objective of this study was to investigate the effectiveness of aspirin combined with calcium supplementation to prevent preeclampsia in women with chronic hypertension. A double-blind, placebo-controlled randomized clinical trial was carried out at the antenatal clinic of a large university hospital in São Paulo, SP, Brazil. A total of 49 women with chronic hypertension and abnormal uterine artery Doppler at 20-27 weeks gestation were randomly assigned to receive placebo (N = 26) or 100 mg aspirin plus 2 g calcium (N = 23) daily until delivery. The main outcome of this pilot study was development of superimposed preeclampsia. Secondary outcomes were fetal growth restriction and preterm birth. The rate of superimposed preeclampsia was 28.6% lower among women receiving aspirin plus calcium than in the placebo group (52.2 vs 73.1%, respectively, P=0.112). The rate of fetal growth restriction was reduced by 80.8% in the supplemented group (25 vs 4.8% in the placebo vs supplemented groups, respectively; P=0.073). The rate of preterm birth was 33.3% in both groups. The combined supplementation of aspirin and calcium starting at 20-27 weeks of gestation produced a nonsignificant decrease in the incidence of superimposed preeclampsia and fetal growth restriction in hypertensive women with abnormal uterine artery Doppler. PMID:24728212

  18. Remineralisation effect of a dual-phase calcium silicate/phosphate gel combined with calcium silicate/phosphate toothpaste on acid-challenged enamel in situ.

    PubMed

    Joiner, Andrew; Schäfer, Fred; Naeeni, Mojgan M; Gupta, Ashok K; Zero, Domenick T

    2014-06-01

    To test if a novel dual-phase gel system (calcium silicate and phosphate with 1450 ppmF, as NaF/MFP; TG) combined with a toothpaste (calcium silicate and sodium phosphate with 1450 ppmF, as MFP; TG) was able to re-harden previously acid-challenged enamel to a greater extent than other toothpastes. The study consisted of a double-blind, randomised, cross-over design with four 7-day treatment legs. In each leg, subjects wearing a partial denture holding four demineralised enamel specimens (25 min in 0.3% citric acid, pH3.8) used either the test regimen (TG+TP) or one of the three controls. (placebo TG+TP; Positive Control - placebo TG+marketed 1450 ppmF toothpaste; Negative Control - placebo TG+placebo TP). Enamel specimens were removed after 1, 2, 3 and 7 days. The gel systems were applied once per day for the first three days during which subjects also brushed with the corresponding toothpaste; this was followed by four days use of the toothpastes only. Toothpastes were used in the conventional way brushing twice per day throughout the seven days. The outcome variable was %Surface Microhardness Recovery calculated after three and seven days of in situ treatment. The results showed a statistically significant (p<0.001) re-hardening effect for all treatments compared to pre-treatment hardness. After three days and after seven days of in situ treatment significantly greater hardening (p<0.05) was found in the samples treated with calcium silicate/phosphate gel system plus calcium silicate/phosphate toothpaste than in the control groups. It is concluded that the test regimen based on the novel dual-phase gel system combined with toothpaste was able to re-harden acid-challenged tooth enamel to a greater extent than a normal fluoride toothpaste. The novel oral care products containing calcium silicate, sodium phosphate salts and fluoride is a new approach to the repair of demineralised enamel. © 2014 Elsevier Ltd. All rights reserved.

  19. Characterisation of Fecal Soap Fatty Acids, Calcium Contents, Bacterial Community and Short-Chain Fatty Acids in Sprague Dawley Rats Fed with Different sn-2 Palmitic Triacylglycerols Diets.

    PubMed

    Wan, Jianchun; Hu, Songyou; Ni, Kefeng; Chang, Guifang; Sun, Xiangjun; Yu, Liangli

    2016-01-01

    The structure of dietary triacylglycerols is thought to influence fatty acid and calcium absorption, as well as intestinal microbiota population of the host. In the present study, we investigated the impact of palmitic acid (PA) esterified at the sn-2 position on absorption of fatty acid and calcium and composition of intestinal microorganisms in rats fed high-fat diets containing either low sn-2 PA (12.1%), medium sn-2 PA (40.4%) or high sn-2 PA (56.3%), respectively. Fecal fatty acid profiles in the soaps were measured by gas chromatography (GC), while fecal calcium concentration was detected by ICP-MS. The fecal microbial composition was assessed using a 16S rRNA high-throughput sequencing technology and fecal short-chain fatty acids were detected by ion chromatograph. Dietary supplementation with a high sn-2 PA fat significantly reduced total fecal contents of fatty acids soap and calcium compared with the medium or low sn-2 PA fat groups. Diet supplementation with sn-2 PA fat did not change the entire profile of the gut microbiota community at phylum level and the difference at genera level also were minimal in the three treatment groups. However, high sn-2 PA fat diet could potentially improve total short-chain fatty acids content in the feces, suggesting that high dietary sn-2 PA fat might have a beneficial effect on host intestinal health.

  20. Calcium and ascorbic acid affect cellular structure and water mobility in apple tissue during osmotic dehydration in sucrose solutions.

    PubMed

    Mauro, Maria A; Dellarosa, Nicolò; Tylewicz, Urszula; Tappi, Silvia; Laghi, Luca; Rocculi, Pietro; Rosa, Marco Dalla

    2016-03-15

    The effects of the addition of calcium lactate and ascorbic acid to sucrose osmotic solutions on cell viability and microstructure of apple tissue were studied. In addition, water distribution and mobility modification of the different cellular compartments were observed. Fluorescence microscopy, light microscopy and time domain nuclear magnetic resonance (TD-NMR) were respectively used to evaluate cell viability and microstructural changes during osmotic dehydration. Tissues treated in a sucrose-calcium lactate-ascorbic acid solution did not show viability. Calcium lactate had some effects on cell walls and membranes. Sucrose solution visibly preserved the protoplast viability and slightly influenced the water distribution within the apple tissue, as highlighted by TD-NMR, which showed higher proton intensity in the vacuoles and lower intensity in cytoplasm-free spaces compared to other treatments. The presence of ascorbic acid enhanced calcium impregnation, which was associated with permeability changes of the cellular wall and membranes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and...

  2. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and...

  3. Citrate salts for preventing and treating calcium containing kidney stones in adults.

    PubMed

    Phillips, Rebecca; Hanchanale, Vishwanath S; Myatt, Andy; Somani, Bhaskar; Nabi, Ghulam; Biyani, C Shekhar

    2015-10-06

    Kidney stones affect people worldwide and have a high rate of recurrence even with treatment. Recurrences are particularly prevalent in people with low urinary citrate levels. These people have a higher incidence of calcium phosphate and calcium oxalate stones. Oral citrate therapy increases the urinary citrate levels, which in turn binds with calcium and inhibits the crystallisation thus reduces stone formation. Despite the widespread use of oral citrate therapy for prevention and treatment of calcium oxalate stones, the evidence to support its clinical efficacy remains uncertain. The objective of this review was to determine the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones. We searched the Cochrane Kidney and Transplant Specialised Register to 29 July 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review. We included randomised controlled trials (RCTs) that assessed the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones in adults treated for a minimum of six months. Two authors assessed studies for inclusion in this review. Data were extracted according to predetermined criteria. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. We included seven studies that included a total of 477 participants, most of whom had oxalate stones. Of these, three studies (247 participants) compared potassium citrate with placebo or no intervention; three (166 participants) compared potassium-sodium citrate with no intervention; and one (64 participants) compared potassium-magnesium citrate with placebo. Overall, quality of the reporting of the included studies was considered moderate to

  4. Calcium contained tap water phenomena: students misconception patterns of acids-bases concept

    NASA Astrophysics Data System (ADS)

    Liliasari, S.; Albaiti, A.; Wahyudi, A.

    2018-05-01

    Acids and bases concept is very important and fundamental concept in learning chemistry. It is one of the chemistry subjects considered as an abstract and difficult concept to understand. The aim of this research was to explore student’s misconception pattern about acids and bases phenomena in daily life, such as calcium contained tap water. This was a qualitative research with descriptive methods. Participants were 546 undergraduate students of chemistry education and chemistry program, and graduate students of chemistry education in West Java, Indonesia. The test to explore students’ misconception about this phenomena was essay test. The results showed that there were five patterns of students’ misconception in explaining the phenomena of calcium carbonate precipitation on heating tap water. Students used irrelevant concepts in explaining this phenomena, i.e. temporary hardness, coagulation, density, and phase concepts. No students had right answer in explaining this phenomena. This research contributes to design meaningful learning and to achieve better understanding.

  5. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or...

  6. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by the...

  7. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by the...

  8. Calcium supplementation for the prevention of colorectal adenomas: A systematic review and meta-analysis of randomized controlled trials.

    PubMed

    Bonovas, Stefanos; Fiorino, Gionata; Lytras, Theodore; Malesci, Alberto; Danese, Silvio

    2016-05-14

    To determine the efficacy of calcium supplementation in reducing the recurrence of colorectal adenomas. We conducted a systematic review and meta-analysis of published studies. We searched PubMed, Scopus, the Cochrane Library, the WHO International Clinical Trials Registry Platform, and the ClinicalTrials.gov website, through December 2015. Randomized, placebo-controlled trials assessing supplemental calcium intake for the prevention of recurrence of adenomas were eligible for inclusion. Two reviewers independently selected studies based on predefined criteria, extracted data and outcomes (recurrence of colorectal adenomas, and advanced or "high-risk" adenomas), and rated each trial's risk-of-bias. Between-study heterogeneity was assessed, and pooled risk ratio (RR) estimates with their 95% confidence intervals (95%CI) were calculated using fixed- and random-effects models. To express the treatment effect in clinical terms, we calculated the number needed to treat (NNT) to prevent one adenoma recurrence. We also assessed the quality of evidence using GRADE. Four randomized, placebo-controlled trials met the eligibility criteria and were included. Daily doses of elemental calcium ranged from 1200 to 2000 mg, while the duration of treatment and follow-up of participants ranged from 36 to 60 mo. Synthesis of intention-to-treat data, for participants who had undergone follow-up colonoscopies, indicated a modest protective effect of calcium in prevention of adenomas (fixed-effects, RR = 0.89, 95%CI: 0.82-0.96; random-effects, RR = 0.87, 95%CI: 0.77-0.98; high quality of evidence). The NNT was 20 (95%CI: 12-61) to prevent one colorectal adenoma recurrence within a period of 3 to 5 years. On the other hand, the association between calcium treatment and advanced adenomas did not reach statistical significance (fixed-effects, RR = 0.92, 95%CI: 0.75-1.13; random-effects, RR = 0.92, 95%CI: 0.71-1.18; moderate quality of evidence). Our results suggest a modest chemopreventive

  9. Calcium supplementation for the prevention of colorectal adenomas: A systematic review and meta-analysis of randomized controlled trials

    PubMed Central

    Bonovas, Stefanos; Fiorino, Gionata; Lytras, Theodore; Malesci, Alberto; Danese, Silvio

    2016-01-01

    AIM: To determine the efficacy of calcium supplementation in reducing the recurrence of colorectal adenomas. METHODS: We conducted a systematic review and meta-analysis of published studies. We searched PubMed, Scopus, the Cochrane Library, the WHO International Clinical Trials Registry Platform, and the ClinicalTrials.gov website, through December 2015. Randomized, placebo-controlled trials assessing supplemental calcium intake for the prevention of recurrence of adenomas were eligible for inclusion. Two reviewers independently selected studies based on predefined criteria, extracted data and outcomes (recurrence of colorectal adenomas, and advanced or “high-risk” adenomas), and rated each trial’s risk-of-bias. Between-study heterogeneity was assessed, and pooled risk ratio (RR) estimates with their 95% confidence intervals (95%CI) were calculated using fixed- and random-effects models. To express the treatment effect in clinical terms, we calculated the number needed to treat (NNT) to prevent one adenoma recurrence. We also assessed the quality of evidence using GRADE. RESULTS: Four randomized, placebo-controlled trials met the eligibility criteria and were included. Daily doses of elemental calcium ranged from 1200 to 2000 mg, while the duration of treatment and follow-up of participants ranged from 36 to 60 mo. Synthesis of intention-to-treat data, for participants who had undergone follow-up colonoscopies, indicated a modest protective effect of calcium in prevention of adenomas (fixed-effects, RR = 0.89, 95%CI: 0.82-0.96; random-effects, RR = 0.87, 95%CI: 0.77-0.98; high quality of evidence). The NNT was 20 (95%CI: 12-61) to prevent one colorectal adenoma recurrence within a period of 3 to 5 years. On the other hand, the association between calcium treatment and advanced adenomas did not reach statistical significance (fixed-effects, RR = 0.92, 95%CI: 0.75-1.13; random-effects, RR = 0.92, 95%CI: 0.71-1.18; moderate quality of evidence). CONCLUSION: Our

  10. Preventing Precipitation in the ISS Urine Processor

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean; Carter, Layne; Williamson, Jill; Chambers, Antja

    2017-01-01

    The ISS Urine Processor Assembly (UPA) was initially designed to achieve 85% recovery of water from pretreated urine on ISS. Pretreated urine is comprised of crew urine treated with flush water, an oxidant (chromium trioxide), and an inorganic acid (sulfuric acid) to control microbial growth and inhibit precipitation. Unfortunately, initial operation of the UPA on ISS resulted in the precipitation of calcium sulfate at 85% recovery. This occurred because the calcium concentration in the crew urine was elevated in microgravity due to bone loss. The higher calcium concentration precipitated with sulfate from the pretreatment acid, resulting in a failure of the UPA due to the accumulation of solids in the Distillation Assembly. Since this failure, the UPA has been limited to a reduced recovery of water from urine to prevent calcium sulfate from reaching the solubility limit. NASA personnel have worked to identify a solution that would allow the UPA to return to a nominal recovery rate of 85%. This effort has culminated with the development of a pretreatment based on phosphoric acid instead of sulfuric acid. By eliminating the sulfate associated with the pretreatment, the brine can be concentrated to a much higher concentration before calcium sulfate reach the solubility limit. This paper summarizes the development of this pretreatment and the testing performed to verify its implementation on ISS.

  11. Biosynthesis of l-Ascorbic Acid and Conversion of Carbons 1 and 2 of l-Ascorbic Acid to Oxalic Acid Occurs within Individual Calcium Oxalate Crystal Idioblasts1

    PubMed Central

    Kostman, Todd A.; Tarlyn, Nathan M.; Loewus, Frank A.; Franceschi, Vincent R.

    2001-01-01

    l-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various 14C-labeled compounds and examined by micro-autoradiography for incorporation of 14C into calcium oxalate crystals. [14C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-14C]AsA also gave heavy labeling of crystals, whereas [6-14C]AsA gave no labeling. Labeled precursors of AsA (l-[1-14C]galactose; d-[1-14C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, d-[1-14C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > l-galactose > d-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via d-mannose and l-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments. PMID:11161021

  12. Dentin remineralization in acid challenge environment via PAMAM and calcium phosphate composite.

    PubMed

    Liang, Kunneng; Weir, Michael D; Xie, Xianju; Wang, Lin; Reynolds, Mark A; Li, Jiyao; Xu, Hockin H K

    2016-11-01

    The objective of this study was to investigate the effects of poly (amido amine) (PAMAM), composite with nanoparticles of amorphous calcium phosphate (NACP), and the combined PAMAM+NACP nanocomposite treatment, on remineralization of demineralized dentin in a cyclic artificial saliva/lactic acid environment for the first time. Dentin specimens were prepared and demineralized with 37% phosphoric acid for 15s. Four groups were prepared: (1) dentin control, (2) dentin coated with PAMAM, (3) dentin with NACP composite, (4) dentin with PAMAM+NACP. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 21days. Acid neutralization and calcium (Ca) and phosphate (P) ion concentrations were measured. The remineralized dentin specimens were examined by scanning electron microscopy (SEM) and hardness testing. NACP nanocomposite had mechanical properties similar to commercial control composites (p>0.1). NACP composite had acid-neutralization and Ca and P ion release capability. PAMAM or NACP composite each alone achieved remineralization and increased the hardness of demineralized dentin (p<0.05). PAMAM+NACP nanocomposite achieved the greatest mineral regeneration in demineralized dentin and the greatest hardness increase in demineralized dentin, which approached the hardness of healthy dentin (p>0.1). The superior remineralization efficacy of PAMAM+NACP was demonstrated for the first time. PAMAM+NACP induced remineralization in demineralized dentin in an acid challenge environment, when conventional remineralization methods such as PAMAM did not work well. The novel PAMAM+NACP composite approach is promising for a wide range of dental applications to inhibit caries and protect tooth structures. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ([CH2OH(CHOH)4COO]2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of gluconic acid with...

  14. Potential Pharmacologic Treatments for Cystinuria and for Calcium Stones Associated with Hyperuricosuria

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goldfarb, David S.

    Two new potential pharmacologic therapies for recurrent stone disease are described. The role of hyperuricosuria in promoting calcium stones is controversial with only some but not all epidemiologic studies demonstrating associations between increasing urinary uric acid excretion and calcium stone disease. The relationship is supported by the ability of uric acid to 'salt out' (or reduce the solubility of) calcium oxalate in vitro. A randomized, controlled trial of allopurinol in patients with hyperuricosuria and normocalciuria was also effective in preventing recurrent stones. Febuxostat, a nonpurine inhibitor of xanthine oxidase (also known as xanthine dehydrogenase or xanthine oxidoreductase) may have advantagesmore » over allopurinol and is being tested in a similar protocol, with the eventual goal of determining whether urate-lowering therapy prevents recurrent calcium stones. Treatments for cystinuria have advanced little in the past 30 years. Atomic force microscopy has been used recently to demonstrate that effective inhibition of cystine crystal growth is accomplished at low concentrations of L-cystine methyl ester and L-cystine dimethyl ester, structural analogs of cystine that provide steric inhibition of crystal growth. In vitro, L-cystine dimethyl ester had a significant inhibitory effect on crystal growth. The drug's safety and effectiveness will be tested in an Slc3a1 knockout mouse that serves as an animal model of cystinuria.« less

  15. Biomediated Precipitation of Calcium Carbonate in a Slightly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.

    2015-12-01

    A slightly acidic hot spring named "Female Tower" (T=73.5 °C, pH=6.64) is located in the Jifei Geothermal Field, Yunnan Province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite, aragonite, and sulfur. Scanning electron microscopy (SEM) analyses revealed that the microbial mats were formed of various coccoid, rod-shaped, and filamentous microbes. Transmission electron microscopy (TEM) showed that the intracellular sulfur granules were commonly associated with these microbes. A culture-independent molecular phylogenetic analysis demonstrated that the majority of the bacteria in the spring were sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We speculated that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the intracellular formation of sulfur granules. In the meantime, this reaction increased the pH in the micron-scale microdomains, which fostered the precipitation of calcium carbonate in the microbial mats. The results of this study indicated that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in slightly acidic hot spring environments.

  16. The role of calcium in the prevention of cardiovascular disease--a review of observational studies and randomized clinical trials.

    PubMed

    Rautiainen, Susanne; Wang, Lu; Manson, JoAnn E; Sesso, Howard D

    2013-11-01

    Calcium is a mineral that is important for bone health and has also been suggested to play a role in the prevention of cardiovascular disease (CVD). Lately, the potential effects of both inadequate and excessive calcium intake have received growing attention. In this review, we summarize the evidence from experimental, epidemiologic, and clinical studies investigating the role of calcium intake, either from the diet or from supplements, as well as blood concentrations, in relation to the risk of CVD in adults. In vitro and in vivo laboratory studies suggest that calcium may be involved in CVD development through multiple pathways, including blood cholesterol, insulin secretion and sensitivity, vasodilation, inflammatory profile, thrombosis, obesity, and vascular calcification. Several prospective epidemiologic studies have examined how dietary or supplemental calcium intake is associated with CVD incidence or mortality in middle-aged and older adults, and the results are inconsistent. Prospective studies investigating blood concentrations of calcium have also reported mixed results. However, changes in blood calcium concentrations may reflect a disturbed calcium phosphate balance, which is associated with increased risk of CVD. To date there is no randomized clinical trial that has been designed specifically to test the effect of calcium supplementation on the risk of CVD as the primary end point. Existing trials have performed secondary analyses, and most of them have been conducted among postmenopausal women. These trials suggest that calcium supplementation has no effect on CVD development; however, they do not allow a definitive conclusion to be drawn. The average daily intake of calcium is low in many populations; however, the evidence for a potential role of dietary or supplemental calcium in the prevention of CVD remains insufficient and inconclusive. Only large-scale randomized trials designed to investigate the effects of calcium supplementation on CVD

  17. REDUCING TOXICITY AND INCREASING EFFICIENCY: ACONITINE WITH LIQUIRITIN AND GLYCYRRHETINIC ACID REGULATE CALCIUM REGULATORY PROTEINS IN RAT MYOCARDIAL CELL.

    PubMed

    Zhang, Yuyan; Yu, Li; Jin, Weifeng; Fan, Hongjing; Li, Min; Zhou, Tianmei; Wan, Haitong; Yang, Jiehong

    2017-01-01

    Compatibility of Radix Aconiti Carmichaeli and Liquorice is known to treat heart diseases such as heart failure and cardiac arrhythmias. This work answers the question that whether the active components (Aconitine, Liquiritin and Glycyrrhetinic Acid) of Radix Aconiti Carmichaeli and Liquorice could result in regulating intracellular calcium homeostasis and calcium cycling, and thereby verifies the therapeutic material basis. The myocardial cells were divided into twelve groups randomly as control group, Aconitine group, nine different dose groups that orthogonal combined with Aconitine, Liquiritin and Glycyrrhetinic Acid, and Verapamil group. The myocardial cellular survival rate and morphology were assessed. The expression of calcium regulation protein(RyR2, NCX1, DHPR-a1) in the myocardial cell by Western-blotting. The results exhibited that Aconitine (120 uM) significantly damaged on myocardial cell, decreased the survival rate and expression of Na + /Ca 2+ exchangers (NCX1) and dihydropteridine reducta-α1 (DHPR-a1), and increased the expression of ryanodine receptor type2 (RyR2) obviously. The compatibility groups (Aconitine, Liquiritin and Glycyrrhetinic Acid) all could against the damage on the myocardial cell by Aconitine at different levels. Aconitine with Liquiritin and Glycyrrhetinic Acid may regulate the expression of calcium-regulated proteins to protect myocardial cells from damage.

  18. REDUCING TOXICITY AND INCREASING EFFICIENCY: ACONITINE WITH LIQUIRITIN AND GLYCYRRHETINIC ACID REGULATE CALCIUM REGULATORY PROTEINS IN RAT MYOCARDIAL CELL

    PubMed Central

    Zhang, Yuyan; Yu, Li; Jin, Weifeng; Fan, Hongjing; Li, Min; Zhou, Tianmei; Wan, Haitong; Yang, Jiehong

    2017-01-01

    Background: Compatibility of Radix Aconiti Carmichaeli and Liquorice is known to treat heart diseases such as heart failure and cardiac arrhythmias. This work answers the question that whether the active components (Aconitine, Liquiritin and Glycyrrhetinic Acid) of Radix Aconiti Carmichaeli and Liquorice could result in regulating intracellular calcium homeostasis and calcium cycling, and thereby verifies the therapeutic material basis. Materials and Methods: The myocardial cells were divided into twelve groups randomly as control group, Aconitine group, nine different dose groups that orthogonal combined with Aconitine, Liquiritin and Glycyrrhetinic Acid, and Verapamil group. The myocardial cellular survival rate and morphology were assessed. The expression of calcium regulation protein(RyR2, NCX1, DHPR-a1) in the myocardial cell by Western-blotting. Results: The results exhibited that Aconitine (120 uM) significantly damaged on myocardial cell, decreased the survival rate and expression of Na+/Ca2+ exchangers (NCX1) and dihydropteridine reducta-α1 (DHPR-a1), and increased the expression of ryanodine receptor type2 (RyR2) obviously. The compatibility groups (Aconitine, Liquiritin and Glycyrrhetinic Acid) all could against the damage on the myocardial cell by Aconitine at different levels. Conclusion: Aconitine with Liquiritin and Glycyrrhetinic Acid may regulate the expression of calcium-regulated proteins to protect myocardial cells from damage. PMID:28638869

  19. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by the...

  20. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by the...

  1. Dietary acid load is associated with lower bone mineral density in men with low intake of dietary calcium.

    PubMed

    Mangano, Kelsey M; Walsh, Stephen J; Kenny, Anne M; Insogna, Karl L; Kerstetter, Jane E

    2014-02-01

    High dietary acid load (DAL) may be detrimental to bone mineral density (BMD). The objectives of the study were to: (1) evaluate the cross-sectional relation between DAL and BMD; and (2) determine whether calcium intake modifies this association. Men (n = 1218) and women (n = 907) aged ≥60 years were included from the National Health and Nutrition Examination Survey 2005-2008. Nutrient intake from 2, 24-hour recalls was used to calculate net endogenous acid production (NEAP) and potential renal acid load (PRAL) (mEq/d). PRAL was calculated from dietary calcium (PRALdiet ) and diet + supplemental calcium (PRALtotal ). Tests for linear trend in adjusted mean BMD of the hip and lumbar spine were performed across energy-adjusted NEAP and PRAL quartiles. Modification by calcium intake (dietary or total) above or below 800 mg/d was assessed by interaction terms. Overall, mean age was 69 ± 0.3 years. Among women, there was no association between NEAP and BMD. PRALdiet was positively associated with proximal femur BMD (p trend = 0.04). No associations were observed with PRALtotal at any BMD site (p range, 0.38-0.82). Among men, no significant associations were observed between BMD and NEAP or PRAL. However, an interaction between PRALdiet and calcium intake was observed with proximal femur BMD (p = 0.08). An inverse association between PRALdiet and proximal femur BMD was detected among men with <800 mg/d dietary calcium (p = 0.02); no associations were found among men with ≥800 mg/d (p = 0.98). A significant interaction with PRALtotal was not observed. In conclusion, when supplemental calcium is considered, there is no association between DAL and BMD among adults. Men with low dietary calcium showed an inverse relation with PRAL at the proximal femur; in women no interaction was observed. This study highlights the importance of calcium intake in counteracting the adverse effect of DAL on bone health. Further research should

  2. Musculoskeletal Health and Injury Prevention

    DTIC Science & Technology

    2008-07-01

    benefits , from maintaining low back health to preventing knee injury; • Pilates is an alternative approach for treating non-specific low back pain...Omega-3 Fatty AcidsCalcium and Vitamin D • Coenzyme Q10 • Capsaicin Cream ( chili peppers) Summary Musculoskeletal health requires: • A

  3. Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement.

    PubMed

    Gambaro, Giovanni; Croppi, Emanuele; Coe, Fredric; Lingeman, James; Moe, Orson; Worcester, Elen; Buchholz, Noor; Bushinsky, David; Curhan, Gary C; Ferraro, Pietro Manuel; Fuster, Daniel; Goldfarb, David S; Heilberg, Ita Pfeferman; Hess, Bernard; Lieske, John; Marangella, Martino; Milliner, Dawn; Preminger, Glen M; Reis Santos, Jose' Manuel; Sakhaee, Khashayar; Sarica, Kemal; Siener, Roswitha; Strazzullo, Pasquale; Williams, James C

    2016-12-01

    Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.

  4. Lactose behaviour in the presence of lactic acid and calcium.

    PubMed

    Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

    2016-08-01

    Physical properties of lactose appeared influenced by presence of lactic acid in the system. Some other components such as Ca may further attenuate lactose behaviour and impact its phase transition. A model-based study was thus implemented with varying concentrations of Ca (0·12, 0·072 or 0·035% w/w) and lactic acid (0·05, 0·2, 0·4 or 1% w/w) in establishing the effects of these two main acid whey constituents on lactose phase behaviour. Concentrated solutions (50% w/w) containing lactose, lactic acid and Ca were analysed for thermal behaviour and structural changes by Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Presence of 1% (w/w) lactic acid and 0·12% (w/w) Ca in lactose solution significantly increased the evaporation enthalpy of water, delayed and increased the energy required for lactose crystallisation as compared to pure lactose. FTIR analysis indicated a strong hydration layer surrounding lactose molecules, restricting water mobility and/or inducing structural changes of lactose, hindering its crystallisation. The formation of calcium lactate, which restricts the diffusion of lactose molecules, is also partly responsible. It appears that Ca removal from acid whey may be a necessary step in improving the processability of acid whey.

  5. Surface modification of calcium-copper hydroxyapatites using polyaspartic acid

    NASA Astrophysics Data System (ADS)

    Othmani, Masseoud; Aissa, Abdallah; Bachoua, Hassen; Debbabi, Mongi

    2013-01-01

    Mixed calcium-copper hydroxyapatite (Ca-CuHAp), with general formula Ca(10-x)Cux(PO4)6(OH)2, where 0 ≤ x ≤ 0.75 was prepared in aqueous medium in the presence of different concentrations of poly-L-aspartic acid (PASP). XRD, IR, TG-DTA, TEM-EDX, AFM and chemical analyses were used to characterize the structure, morphology and composition of the products. All techniques show the formation of new hybrid compounds Ca-CuHAp-PASP. The presence of the grafting moiety on the apatitic material is more significant with increasing of copper amount and/or organic concentration in the starting solution. These increases lead to the affectation of apatite crystallinity. The IR spectroscopy shows the conservation of (Psbnd OH) band of (HPO4)2- groups, suggesting that PASP acid was interacted only with metallic cations of hydroxyapatite.

  6. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium citrate. 184.1195 Section 184.1195 Food and... Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with...

  7. Long-term effects of L- and N-type calcium channel blocker on uric acid levels and left atrial volume in hypertensive patients.

    PubMed

    Masaki, Mitsuru; Mano, Toshiaki; Eguchi, Akiyo; Fujiwara, Shohei; Sugahara, Masataka; Hirotani, Shinichi; Tsujino, Takeshi; Komamura, Kazuo; Koshiba, Masahiro; Masuyama, Tohru

    2016-11-01

    Left ventricular (LV) diastolic dysfunction is associated with hypertension and hyperuricemia. However, it is not clear whether the L- and N-type calcium channel blocker will improve LV diastolic dysfunction through the reduction of uric acid. The aim of this study was to investigate the effects of anti-hypertensive therapy, the L- and N-type calcium channel blocker, cilnidipine or the L-type calcium channel blocker, amlodipine, on left atrial reverse remodeling and uric acid in hypertensive patients. We studied 62 patients with untreated hypertension, randomly assigned to cilnidipine or amlodipine for 48 weeks. LV diastolic function was assessed with the left atrial volume index (LAVI), mitral early diastolic wave (E), tissue Doppler early diastolic velocity (E') and the ratio (E/E'). Serum uric acid levels were measured before and after treatment. After treatment, systolic and diastolic blood pressures equally dropped in both groups. LAVI, E/E', heart rate and uric acid levels decreased at 48 weeks in the cilnidipine group but not in the amlodipine group. The % change from baseline to 48 weeks in LAVI, E wave, E/E' and uric acid levels were significantly lower in the cilnidipine group than in the amlodipine group. Larger %-drop in uric acid levels were associated with larger %-reduction of LAVI (p < 0.01). L- and N-type calcium channel blocker but not L-type calcium channel blocker may improve LV diastolic function in hypertensive patients, at least partially through the decrease in uric acid levels.

  8. Isolation of an acidic protein from cholesterol gallstones, which inhibits the precipitation of calcium carbonate in vitro.

    PubMed Central

    Shimizu, S; Sabsay, B; Veis, A; Ostrow, J D; Rege, R V; Dawes, L G

    1989-01-01

    In seeking to identify nucleating/antinucleating proteins involved in the pathogenesis of cholesterol gallstones, a major acidic protein was isolated from each of 13 samples of cholesterol gallstones. After the stones were extracted with methyl t-butyl ether to remove cholesterol, and methanol to remove bile salts and other lipids, they were demineralized with EDTA. The extracts were desalted with Sephadex-G25, and the proteins separated by PAGE. A protein was isolated, of molecular weight below 10 kD, which included firmly-bound diazo-positive yellow pigments and contained 24% acidic, but only 7% basic amino acid residues. The presence of N-acetyl glucosamine suggested that this was a glycoprotein. This protein at concentrations as low as 2 micrograms/ml, but neither human serum albumin nor its complex with bilirubin, inhibited calcium carbonate precipitation from a supersaturated solution in vitro. This protein could be precipitated from 0.15 M NaCl solution by the addition of 0.5 M calcium chloride. Considering that cholesterol gallstones contain calcium and pigment at their centers, and that small acidic proteins are important regulators in other biomineralization systems, this protein seems likely to play a role in the pathogenesis of cholesterol gallstones. Images PMID:2592569

  9. Calcium signaling in neuronal cells exposed to the munitions compound Cyclotrimethylenetrinitramine (RDX).

    PubMed

    Ehrich, Marion; Wu, Xiaohua; Werre, Stephen R; Major, Michael A; McCain, Wilfred C; Reddy, Gunda

    2009-01-01

    Cyclotrimethylenetrinitramine (RDX) has been used extensively as an explosive in military munitions. Mechanisms for seizure production, seen in past animal studies, have not been described. Increased calcium levels contribute to excitotoxicity, so in this study neuroblastoma cells are loaded with calcium-indicating dye before application of 1.5 microM to 7.5 mM RDX, with fluorescence recorded for 30 cycles of 11 seconds each. The lowest concentration of RDX increases calcium fluorescence significantly above baseline for cycles 2 to 8; millimolar concentrations increase calcium fluorescence significantly above baseline for cycles 2 to 30. Increases in calcium, like those of 200 nM carbachol, are prevented with 10 mM of calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N,N tetra-acetic acid (EGTA, tetrasodium salt). Calcium channel blocker verapamil (20 microM), Ca(2+)-ATPase inhibitor thapsigargin (5 microM), and general membrane stabilizer lidocaine (10 mM) partially attenuate carbachol- and RDX-induced increases in calcium, suggesting that RDX transiently increases intracellular calcium by multiple mechanisms.

  10. Multivitamin, calcium and folic acid supplements and the risk of colorectal cancer in Lynch syndrome.

    PubMed

    Chau, Rowena; Dashti, Seyedeh Ghazaleh; Ait Ouakrim, Driss; Buchanan, Daniel D; Clendenning, Mark; Rosty, Christophe; Winship, Ingrid M; Young, Joanne P; Giles, Graham G; Macrae, Finlay A; Boussioutas, Alex; Parry, Susan; Figueiredo, Jane C; Levine, A Joan; Ahnen, Dennis J; Casey, Graham; Haile, Robert W; Gallinger, Steven; Le Marchand, Loïc; Thibodeau, Stephen N; Lindor, Noralane M; Newcomb, Polly A; Potter, John D; Baron, John A; Hopper, John L; Jenkins, Mark A; Win, Aung Ko

    2016-06-01

    People with a DNA mismatch repair (MMR) gene mutation have a substantially elevated risk of colorectal cancer (CRC) but the modifiers of this risk are not well established. We investigated the association between dietary supplement intake and CRC risk for carriers. This study included 1966 (56% female) carriers of an MMR gene mutation (719 MLH1, 931 MSH2, 211 MSH6 and 105 PMS2) who were recruited from the USA, Canada, Australia and New Zealand into the Colon Cancer Family Registry between 1997 and 2012. Information on lifestyle factors including supplement intake was collected at the time of recruitment. Using Cox proportional hazards regression weighted to correct for ascertainment bias, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between self-reported multivitamin, calcium and folic acid supplement intake and CRC risk. Of 744 carriers with CRC, 18%, 6% and 5% reported intake of multivitamin, calcium and folic acid supplements for at least 1 month, respectively, compared with 27%, 11% and 10% of 1222 carriers without CRC. After adjusting for identified confounding variables, a decreased CRC risk was associated with multivitam inintake for at least 3 years (HR 0.47, 95% CI 0.32-0.69) and calcium intake for at least 3 years(HR 0.42, 95% CI 0.23-0.74), compared with never users. There was no evidence of an association between folic acid supplement intake and CRC risk (P = 0.82). Intake of multivitamin and calcium supplements might be associated with a decreased risk of CRC for MMR gene mutation carriers. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

  11. Media calcification, low erythrocyte magnesium, altered plasma magnesium, and calcium homeostasis following grafting of the thoracic aorta to the infrarenal aorta in the rat--differential preventive effects of long-term oral magnesium supplementation alone and in combination with alkali.

    PubMed

    Schwille, P O; Schmiedl, A; Schwille, R; Brunner, P; Kissler, H; Cesnjevar, R; Gepp, H

    2003-03-01

    Calcifications in arterial media are clinically well documented, but the role played by magnesium in pathophysiology and therapy is uncertain. To clarify this, an animal model in which the juxtacardial aorta was grafted to the infrarenal aorta, and the subsequent calcifications in the media of the graft and their response to oral supplementation with three magnesium-containing and alkalinizing preparations was investigated. Groups of highly inbred rats were formed as follows: sham-operation (Sham, n = 12), aorta transplantation (ATx, n = 12), ATx + magnesium citrate (MgC, n = 12), ATx + MgC + potassium citrate (MgCPC, n = 12), ATx + MgC + MgCPC (MgCPCSB, n = 12). At 84 (+/-2) days after ATx with or without treatment the following observations were made: (1) weight gain and general status were normal; (2) ATx rats developed massive media calcification, mineral accumulation in the graft, decreased erythrocyte magnesium and plasma parathyroid hormone, and increased plasma ionized magnesium and calcium, and uric acid; (3) Mg-treated rats developed variable degrees of metabolic alkalosis, but only MgCPCSB supplementation prevented calcifications. Additional findings after ATx alone were: imbalance in endothelin and nitric oxide production, the mineral deposited in media was poorly crystallized calcium phosphate, calcium exchange between plasma and graft, and bone resorption were unchanged. The superior anti-calcification effect of MgCPCSB was characterized by complete restoration of normal extracellular mineral homeostasis and uric acid, but sub-optimal normalization of erythrocyte magnesium. It was concluded that in the rat: (1) ATx causes loss of cellular magnesium, excess of extracellular magnesium and calcium in the presence of apparently unchanged bone resorption, and increased uricemia; (2) ATx facilitates enhanced influx of calcium into vascular tissue, leading to calcium phosphate deposition in the media; (3) ATx-induced calcification is prevented by dietary

  12. Exopolysaccharides regulate calcium flow in cariogenic biofilms

    PubMed Central

    Varenganayil, Muth M.; Decho, Alan W.

    2017-01-01

    Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS) provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya’s agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC) by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR) spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC). Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries. PMID:29023506

  13. Effect of potential renal acid load of foods on urinary citrate excretion in calcium renal stone formers.

    PubMed

    Trinchieri, Alberto; Lizzano, Renata; Marchesotti, Federica; Zanetti, Giampaolo

    2006-02-01

    The aim of this study was to investigate the influence of the potential renal acid load (PRAL) of the diet on the urinary risk factors for renal stone formation. The present series comprises 187 consecutive renal calcium stone patients (114 males, 73 females) who were studied in our stone clinic. Each patient was subjected to an investigation including a 24-h dietary record and 24-h urine sample taken over the same period. Nutrients and calories were calculated by means of food composition tables using a computerized procedure. Daily PRAL was calculated considering the mineral and protein composition of foods, the mean intestinal absorption rate for each nutrient and the metabolism of sulfur-containing amino acids. Sodium, potassium, calcium, magnesium, phosphate, oxalate, urate, citrate, and creatinine levels were measured in the urine. The mean daily PRAL was higher in male than in female patients (24.1+/-24.0 vs 16.1+/-20.1 mEq/day, P=0.000). A significantly (P=0.01) negative correlation (R=-0.18) was found between daily PRAL and daily urinary citrate, but no correlation between PRAL and urinary calcium, oxalate, and urate was shown. Daily urinary calcium (R=0.186, P=0.011) and uric acid (R=0.157, P=0.033) were significantly related to the dietary intake of protein. Daily urinary citrate was significantly related to the intakes of copper (R=0.178, P=0.015), riboflavin (R=0.20, P=0.006), piridoxine (R=0.169, P=0.021) and biotin (R=0.196, P=0.007). The regression analysis by stepwise selection confirmed the significant negative correlation between PRAL and urinary citrate (P=0.002) and the significant positive correlation between riboflavin and urinary citrate (P=0.000). Urinary citrate excretion of renal stone formers (RSFs) is highly dependent from dietary acid load. The computation of the renal acid load is advisable to investigate the role of diet in the pathogenesis of calcium stone disease and it is also a useful tool to evaluate the lithogenic potential of

  14. Fatty acid translocase promoted hepatitis B virus replication by upregulating the levels of hepatic cytosolic calcium.

    PubMed

    Huang, Jian; Zhao, Lei; Yang, Ping; Chen, Zhen; Ruan, Xiong Z; Huang, Ailong; Tang, Ni; Chen, Yaxi

    2017-09-15

    Hepatitis B virus (HBV) is designated a "metabolovirus" due to the intimate connection between the virus and host metabolism. The nutrition state of the host plays a relevant role in the severity of HBV infection. Metabolic syndrome (MS) is prone to increasing HBV DNA loads and accelerating the progression of liver disease in patients with chronic hepatitis B (CHB). Cluster of differentiation 36 (CD36), also named fatty acid translocase, is known to facilitate long-chain fatty acid uptake and contribute to the development of MS. We recently found that CD36 overexpression enhanced HBV replication. In this study, we further explored the mechanism by which CD36 overexpression promotes HBV replication. Our data showed that CD36 overexpression increased HBV replication, and CD36 knockdown inhibited HBV replication. RNA sequencing found some of the differentially expressed genes were involved in calcium ion homeostasis. CD36 overexpression elevated the cytosolic calcium level, and CD36 knockdown decreased the cytosolic calcium level. Calcium chelator BAPTA-AM could override the HBV replication increased by CD36 overexpression, and the calcium activator thapsigargin could improve the HBV replication reduced by CD36 knockdown. We further found that CD36 overexpression activated Src kinase, which plays an important role in the regulation of the store-operated Ca 2+ channel. An inhibitor of Src kinase (SU6656) significantly reduced the CD36-induced HBV replication. We identified a novel link between CD36 and HBV replication, which is associated with cytosolic calcium and the Src kinase pathway. CD36 may represent a potential therapeutic target for the treatment of CHB patients with MS. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Effect of calcium soaps of fatty acids and administration of somatotropin in early lactation on productive and reproductive performance of high producing dairy cows.

    PubMed

    Moallem, U; Kaim, M; Folman, Y; Sklan, D

    1997-09-01

    This study examined the mechanisms by which calcium soaps of fatty acids and bovine somatotropin (bST) affect production and reproduction of high producing cows. Calcium soaps of fatty acids were fed at 2.2% dry matter, and 500 mg of Zn-sometribove (Monsanto Inc., St Louis, MO) were injected subcutaneously every 14 d from 10 to 150 d in milk (DIM). Production of fat-corrected milk was increased by 3.5 kg/d when calcium soaps of fatty acids were fed, by 6.1 kg/d when bST was administered, and by 7.4 kg/d when calcium soaps of fatty acids were fed and bST was administered. Body weight was similar for cows on all treatments until 85 DIM after which cows that were treated with bST had lower body weights. Body condition scores decreased more for cows treated with bST and began increasing later and more slowly. Treatment with bST resulted in more cows that experienced first ovulation after 30 DIM, and more cows on the control treatment exhibited first estrus before 35 DIM. Days open were greater when bST was administered. After the first artificial insemination, conception rates were similar for cows on the control treatment and for cows fed calcium soaps of fatty acids; conception rates after the first artificial insemination were low for all cows treated with bST. Pregnancy rates at 120 and 150 DIM were decreased by bST. Number of DIM to first ovulation, number of DIM to first estrus, and days open were negatively correlated with glucose and cholesterol concentrations in plasma. Production of fat-corrected milk was correlated with days open and with concentrations of triglycerides in plasma, nonesterified fatty acids, and cholesterol. Increased production had different effects on reproduction when induced by calcium soaps of fatty acids or bST treatment. Some of the adverse effects of bST treatments were alleviated by calcium soaps of fatty acids.

  16. Calcium and Vitamin D Supplementation for Prevention of Preeclampsia: A Systematic Review and Network Meta-Analysis

    PubMed Central

    Khaing, Win; Vallibhakara, Sakda Arj-Ong; Tantrakul, Visasiri; Vallibhakara, Orawin; Rattanasiri, Sasivimol; McEvoy, Mark; Attia, John; Thakkinstian, Ammarin

    2017-01-01

    Vitamin D supplementation effects with or without calcium in pregnancy for reducing risk of preeclampsia and gestational or pregnancy induced hypertension are controversial. Literature was systematically searched in Medline, Scopus and Cochrane databases from inception to July 2017. Only randomized controlled trials (RCTs) in English were selected if they had any pair of interventions (calcium, vitamin D, both, or placebo). Systematic review with two-step network-meta-analysis was used to indirectly estimate supplementary effects. Twenty-seven RCTs with 28,000 women were eligible. A direct meta-analysis suggested that calcium, vitamin D, and calcium plus vitamin D could lower risk of preeclampsia when compared to placebo with the pooled risk ratios (RRs) of 0.54 (0.41, 0.70), 0.47 (0.24, 0.89) and 0.50 (0.32, 0.78), respectively. Results of network meta-analysis were similar with the corresponding RRs of 0.49 (0.35, 0.69), 0.43 (0.17, 1.11), and 0.57 (0.30, 1.10), respectively. None of the controls were significant. Efficacy of supplementation, which was ranked by surface under cumulative ranking probabilities, were: vitamin D (47.4%), calcium (31.6%) and calcium plus vitamin D (19.6%), respectively. Calcium supplementation may be used for prevention for preeclampsia. Vitamin D might also worked well but further large scale RCTs are warranted to confirm our findings. PMID:29057843

  17. Calcium and Vitamin D Supplementation for Prevention of Preeclampsia: A Systematic Review and Network Meta-Analysis.

    PubMed

    Khaing, Win; Vallibhakara, Sakda Arj-Ong; Tantrakul, Visasiri; Vallibhakara, Orawin; Rattanasiri, Sasivimol; McEvoy, Mark; Attia, John; Thakkinstian, Ammarin

    2017-10-18

    Vitamin D supplementation effects with or without calcium in pregnancy for reducing risk of preeclampsia and gestational or pregnancy induced hypertension are controversial. Literature was systematically searched in Medline, Scopus and Cochrane databases from inception to July 2017. Only randomized controlled trials (RCTs) in English were selected if they had any pair of interventions (calcium, vitamin D, both, or placebo). Systematic review with two-step network-meta-analysis was used to indirectly estimate supplementary effects. Twenty-seven RCTs with 28,000 women were eligible. A direct meta-analysis suggested that calcium, vitamin D, and calcium plus vitamin D could lower risk of preeclampsia when compared to placebo with the pooled risk ratios (RRs) of 0.54 (0.41, 0.70), 0.47 (0.24, 0.89) and 0.50 (0.32, 0.78), respectively. Results of network meta-analysis were similar with the corresponding RRs of 0.49 (0.35, 0.69), 0.43 (0.17, 1.11), and 0.57 (0.30, 1.10), respectively. None of the controls were significant. Efficacy of supplementation, which was ranked by surface under cumulative ranking probabilities, were: vitamin D (47.4%), calcium (31.6%) and calcium plus vitamin D (19.6%), respectively. Calcium supplementation may be used for prevention for preeclampsia. Vitamin D might also worked well but further large scale RCTs are warranted to confirm our findings.

  18. Application of acidic calcium sulfate and e-polylysine to pre-rigor beef rounds for reduction of pathogens

    USDA-ARS?s Scientific Manuscript database

    Foodborne illness continues to be a serious public health problem and is a major concern for the United States food industry. This study evaluated the effectiveness of warm solutions of acidic calcium sulfate (ACS), lactic acid (LA), episolon-polylysine (EPL), ACS plus EPL, and sterile distilled wa...

  19. Solubility and bioavailability of stabilized amorphous calcium carbonate.

    PubMed

    Meiron, Oren E; Bar-David, Elad; Aflalo, Eliahu D; Shechter, Assaf; Stepensky, David; Berman, Amir; Sagi, Amir

    2011-02-01

    Since its role in the prevention of osteoporosis in humans was proven some 30 years ago, calcium bioavailability has been the subject of numerous scientific studies. Recent technology allowing the production of a stable amorphous calcium carbonate (ACC) now enables a bioavailability analysis of this unique form of calcium. This study thus compares the solubility and fractional absorption of ACC, ACC with chitosan (ACC-C), and crystalline calcium carbonate (CCC). Solubility was evaluated by dissolving these preparations in dilute phosphoric acid. The results demonstrated that both ACC and ACC-C are more soluble than CCC. Fractional absorption was evaluated by intrinsically labeling calcium carbonate preparations with (45)Ca, orally administrated to rats using gelatin capsules. Fractional absorption was determined by evaluating the percentage of the administrated radioactive dose per milliliter that was measured in the serum, calcium absorption in the femur, and whole-body retention over a 34-hour period. Calcium serum analysis revealed that calcium absorption from ACC and ACC-C preparations was up to 40% higher than from CCC, whereas retention of ACC and ACC-C was up to 26.5% higher than CCC. Absorbed calcium in the femurs of ACC-administrated rats was 30% higher than in CCC-treated animals, whereas 15% more calcium was absorbed following ACC-C treatment than following CCC treatment. This study demonstrates the enhanced solubility and bioavailability of ACC over CCC. The use of stable ACC as a highly bioavailable dietary source for calcium is proposed based on the findings of this study. Copyright © 2011 American Society for Bone and Mineral Research.

  20. Effect of surface modification of nanofibres with glutamic acid peptide on calcium phosphate nucleation and osteogenic differentiation of marrow stromal cells.

    PubMed

    Karaman, Ozan; Kumar, Ankur; Moeinzadeh, Seyedsina; He, Xuezhong; Cui, Tong; Jabbari, Esmaiel

    2016-02-01

    Biomineralization is mediated by extracellular matrix (ECM) proteins with amino acid sequences rich in glutamic acid. The objective of this study was to investigate the effect of calcium phosphate deposition on aligned nanofibres surface-modified with a glutamic acid peptide on osteogenic differentiation of rat marrow stromal cells. Blend of EEGGC peptide (GLU) conjugated low molecular weight polylactide (PLA) and high molecular weight poly(lactide-co-glycolide) (PLGA) was electrospun to form aligned nanofibres (GLU-NF). The GLU-NF microsheets were incubated in a modified simulated body fluid for nucleation of calcium phosphate crystals on the fibre surface. To achieve a high calcium phosphate to fibre ratio, a layer-by-layer approach was used to improve diffusion of calcium and phosphate ions inside the microsheets. Based on dissipative particle dynamics simulation of PLGA/PLA-GLU fibres, > 80% of GLU peptide was localized to the fibre surface. Calcium phosphate to fibre ratios as high as 200%, between those of cancellous (160%) and cortical (310%) bone, was obtained with the layer-by-layer approach. The extent of osteogenic differentiation and mineralization of marrow stromal cells seeded on GLU-NF microsheets was directly related to the amount of calcium phosphate deposition on the fibres prior to cell seeding. Expression of osteogenic markers osteopontin, alkaline phosphatase (ALP), osteocalcin and type 1 collagen increased gradually with calcium phosphate deposition on GLU-NF microsheets. Results demonstrate that surface modification of aligned synthetic nanofibres with EEGGC peptide dramatically affects nucleation and growth of calcium phosphate crystals on the fibres leading to increased osteogenic differentiation of marrow stromal cells and mineralization. Copyright © 2013 John Wiley & Sons, Ltd.

  1. The High Calcium, High Phosphorus Rescue Diet Is Not Suitable to Prevent Secondary Hyperparathyroidism in Vitamin D Receptor Deficient Mice.

    PubMed

    Grundmann, Sarah M; Brandsch, Corinna; Rottstädt, Daniela; Kühne, Hagen; Stangl, Gabriele I

    2017-01-01

    The vitamin D receptor (VDR) knockout (KO) mouse is a common model to unravel novel metabolic functions of vitamin D. It is recommended to feed these mice a high calcium (2%), high phosphorus (1.25%) diet, termed rescue diet (RD) to prevent hypocalcaemia and secondary hyperparathyroidism. First, we characterized the individual response of VDR KO mice to feeding a RD and found that the RD was not capable of normalizing the parathyroid hormone (PTH) concentrations in each VDR KO mouse. In a second study, we aimed to study whether RD with additional 1 and 2% calcium (in total 3 and 4% of the diet) is able to prevent secondary hyperparathyroidism in the VDR KO mice. Wild type (WT) mice and VDR KO mice that received a normal calcium and phosphorus diet (ND) served as controls. Data demonstrated that the RD was no more efficient than the ND in normalizing PTH levels. An excessive dietary calcium concentration of 4% was required to reduce serum PTH concentrations in the VDR KO mice to PTH levels measured in WT mice. This diet, however, resulted in higher concentrations of circulating intact fibroblast growth factor 23 (iFGF23). To conclude, the commonly used RD is not suitable to normalize the serum PTH in VDR KO mice. Extremely high dietary calcium concentrations are necessary to prevent secondary hyperthyroidism in these mice, with the consequence that iFGF23 concentrations are being raised. Considering that PTH and iFGF23 exert numerous VDR independent effects, data obtained from VDR KO mice cannot be attributed solely to vitamin D.

  2. Calcium binding to Procambarus clarkii sarcoplasmic calcium binding protein splice variants.

    PubMed

    Rohrback, Suzanne E; Wheatly, Michele G; Gillen, Christopher M

    2015-01-01

    Sarcoplasmic calcium binding protein (SCP) is a high-affinity calcium buffering protein expressed in muscle of crayfish and other invertebrates. In previous work, we identified three splice variants of Procambarus clarkii SCP (pcSCP1a, pcSCP1b, and pcSCP1c) that differ in a 37 amino acid region that lies mainly between the 2nd and 3ed EF-hand calcium binding domain. To evaluate the function of the proteins encoded by the pcSCP1 transcripts, we produced recombinant pcSCP1 and used tryptophan fluorescence to characterize calcium binding. Tryptophan fluorescence of pcSCP1a decreased in response to increased calcium, while tryptophan fluorescence of the pcSCP1b and pcSCP1c variants increased. We estimated calcium binding constants and Hill coefficients with two different equations: the standard Hill equation and a modified Hill equation that accounts for contributions from two different tryptophans. The approaches gave similar results. Steady-state calcium binding constants (Kd) ranged from 2.7±0.7×10(-8)M to 5.6±0.1×10(-7)M, consistent with previous work. Variants displayed significantly different apparent calcium affinities, which were decreased in the presence of magnesium. Calcium Kd was lowest for pcSCP1a and highest for pcSCP1c. Site-directed mutagenesis of pcSCP1c residues to the amino acids of pcSCP1b decreased the calcium Kd, identifying residues outside the EF-hand domains that contribute to calcium binding in crayfish SCP. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Development of calcium phosphate cement using chitosan and citric acid for bone substitute materials.

    PubMed

    Yokoyama, Atsuro; Yamamoto, Satoru; Kawasaki, Takao; Kohgo, Takao; Nakasu, Masanori

    2002-02-01

    We developed a calcium phosphate cement that could be molded into any desired shape due to its chewing-gum-like consistency after mixing. The powder component of the cement consists of alpha-tricalcium phosphate and tetracalcium phosphate, which were made by decomposition of hydroxyapatite ceramic blocks. The liquid component consists of citric acid, chitosan and glucose solution. In this study, we used 20% citric acid (group 20) and 45% citric acid (group 45). The mechanical properties and biocompatibility of this new cement were investigated. The setting times of cements were 5.5 min, in group 20 and 6.4 min, in group 45. When incubated in physiological saline, the cements were transformed to hydroxyapatite at 3, and 6 weeks, the compressive strengths were 15.6 and 20.7 MPa, in group 45 and group 20, respectively. The inflammatory response around the cement implanted on the bone and in the subcutaneous tissue in rats was more prominent in group 45 than in group 20 at 1 week after surgery. After 4 weeks, the inflammation disappeared and the cement had bound to bone in both groups. These results indicate that this new calcium phosphate cement is a suitable bone substitute material and that the concentration of citric acid in the liquid component affects its mechanical properties and biocompatibility.

  4. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for the...

  5. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for the...

  6. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for the...

  7. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... potassium sodium salt (PMN P-00-7; CAS No.125005-87-0) is subject to reporting under this section for the...

  8. Correction: Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

    DOE PAGES

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; ...

    2015-07-20

    One central question is how specificity in cellular responses to the eukaryotic second messenger Ca 2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca 2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca 2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca 2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruplemore » mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca 2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca 2+-dependent and Ca 2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca 2+-signaling on a cellular, genetic, and biochemical level.« less

  9. Correction: Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

    DOE PAGES

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; ...

    2015-07-29

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca 2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca 2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca 2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca 2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruplemore » mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca 2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca 2+-dependent and Ca 2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca 2+-signaling on a cellular, genetic, and biochemical level.« less

  10. A comprehensive search for calcium binding sites critical for TMEM16A calcium-activated chloride channel activity

    PubMed Central

    Tien, Jason; Peters, Christian J; Wong, Xiu Ming; Cheng, Tong; Jan, Yuh Nung; Jan, Lily Yeh; Yang, Huanghe

    2014-01-01

    TMEM16A forms calcium-activated chloride channels (CaCCs) that regulate physiological processes such as the secretions of airway epithelia and exocrine glands, the contraction of smooth muscles, and the excitability of neurons. Notwithstanding intense interest in the mechanism behind TMEM16A-CaCC calcium-dependent gating, comprehensive surveys to identify and characterize potential calcium sensors of this channel are still lacking. By aligning distantly related calcium-activated ion channels in the TMEM16 family and conducting systematic mutagenesis of all conserved acidic residues thought to be exposed to the cytoplasm, we identify four acidic amino acids as putative calcium-binding residues. Alterations of the charge, polarity, and size of amino acid side chains at these sites alter the ability of different divalent cations to activate the channel. Furthermore, TMEM16A mutant channels containing double cysteine substitutions at these residues are sensitive to the redox potential of the internal solution, providing evidence for their physical proximity and solvent accessibility. DOI: http://dx.doi.org/10.7554/eLife.02772.001 PMID:24980701

  11. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Calcium alginate is prepared by...

  12. Incorporation of casein phosphopeptide-amorphous calcium phosphate into a glass-ionomer cement.

    PubMed

    Mazzaoui, S A; Burrow, M F; Tyas, M J; Dashper, S G; Eakins, D; Reynolds, E C

    2003-11-01

    Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes have been shown to prevent demineralization and promote remineralization of enamel subsurface lesions in animal and in situ caries models. The aim of this study was to determine the effect of incorporating CPP-ACP into a self-cured glass-ionomer cement (GIC). Incorporation of 1.56% w/w CPP-ACP into the GIC significantly increased microtensile bond strength (33%) and compressive strength (23%) and significantly enhanced the release of calcium, phosphate, and fluoride ions at neutral and acidic pH. MALDI mass spectrometry also showed casein phosphopeptides from the CPP-ACP nanocomplexes to be released. The release of CPP-ACP and fluoride from the CPP-ACP-containing GIC was associated with enhanced protection of the adjacent dentin during acid challenge in vitro.

  13. Primary prevention of dental erosion by calcium and fluoride: a systematic review.

    PubMed

    Zini, A; Krivoroutski, Y; Vered, Y

    2014-02-01

    Overviews of the current literature only provide summaries of existing relevant preventive strategies for dental erosion. To perform a systematic review according to the quantitative meta-analysis method of the scientific literature on prevention of dental erosion. The focused question will address primary prevention of dental erosion by calcium and fluoride. Randomized clinical trials (RCTs) regarding dental erosion prevention. The search included five databases: Embase, Cochrane database of systematic reviews, PubMed (MEDLINE), FDA publication and Berman medical library of the Hebrew University. The search included data in the English language, with effect on preventing dental erosion always presented as mean enamel loss and measured by profilometer. Statistical meta-analysis was performed by StatsDirect program and PEPI statistical software. Fixed- and random-effect models were used to analyse the data. Heterogeneity tests were employed to validate the fixed-effect model assumption. A total of 475 articles on dental erosion prevention were located. A four-stage selection process was employed, and 10 RCT articles were found to be suitable for meta-analysis. The number of studies on prevention of dental erosion maintaining standards of evidence-based dentistry remains insufficient to reach any definite conclusions. The focused questions of this review cannot be addressed according to the existing literature. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Extracellular calcium regulates protein tyrosine phosphorylation through calcium-sensing receptor (CaSR) in stallion sperm.

    PubMed

    Macías-García, Beatriz; Rocha, Antonio; González-Fernández, Lauro

    2016-03-01

    Protein tyrosine phosphorylation (PY), a hallmark of sperm capacitation, is inhibited by extracellular calcium in stallion sperm. The objective of this study was to determine the presence and influence of the calcium-sensing receptor (CaSR) in this phenomenon. First, the presence of the CaSR was demonstrated in stallion sperm. We then tested its function in these gametes using its inhibitor NPS2143 or its agonist AC34356. Sperm were capacitated for 4 hr in modified Whitten's medium with 25 mM bicarbonate plus NPS2143 and 2.4 mM calcium or AC34356 alone, followed by analysis of PY. Inhibition of CaSR with NPS2143 prevented the calcium-dependent PY inhibition in a dose-dependent manner (5, 10, and 15 μM) whereas AC34356 (100 μM) inhibited PY similarly to calcium. Stallion sperm motility and viability significantly decreased in presence of 15 μM of NPS2143 whereas only sperm motility decreased with 100 μM of AC34356. CaSR function was also studied in the complete absence of calcium by including 2 mM ethylene glycol tetraacetic acid (EGTA); under these conditions, AC34356 again inhibited PY, but this time induced a significant increase in sperm motility. Inhibition of calmodulin by W-7 did not recover the AC34356-mediated PY inhibition. When stallion sperm were incubated under capacitating conditions (calcium, bicarbonate, plus bovine serum albumin) at elevated pH (7.9 or 8.5) AC34356 did not block PY. These results thus elucidate the effect of extracellular conditions on the regulation of CaSR, and point to its modulatory role on stallion sperm PY, motility, and viability. Mol. Reprod. Dev. 83: 236-245, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Calcium specificity signaling mechanisms in abscisic acid signal transduction in Arabidopsis guard cells

    PubMed Central

    Brandt, Benjamin; Munemasa, Shintaro; Wang, Cun; Nguyen, Desiree; Yong, Taiming; Yang, Paul G; Poretsky, Elly; Belknap, Thomas F; Waadt, Rainer; Alemán, Fernando; Schroeder, Julian I

    2015-01-01

    A central question is how specificity in cellular responses to the eukaryotic second messenger Ca2+ is achieved. Plant guard cells, that form stomatal pores for gas exchange, provide a powerful system for in depth investigation of Ca2+-signaling specificity in plants. In intact guard cells, abscisic acid (ABA) enhances (primes) the Ca2+-sensitivity of downstream signaling events that result in activation of S-type anion channels during stomatal closure, providing a specificity mechanism in Ca2+-signaling. However, the underlying genetic and biochemical mechanisms remain unknown. Here we show impairment of ABA signal transduction in stomata of calcium-dependent protein kinase quadruple mutant plants. Interestingly, protein phosphatase 2Cs prevent non-specific Ca2+-signaling. Moreover, we demonstrate an unexpected interdependence of the Ca2+-dependent and Ca2+-independent ABA-signaling branches and the in planta requirement of simultaneous phosphorylation at two key phosphorylation sites in SLAC1. We identify novel mechanisms ensuring specificity and robustness within stomatal Ca2+-signaling on a cellular, genetic, and biochemical level. DOI: http://dx.doi.org/10.7554/eLife.03599.001 PMID:26192964

  16. Physical-Mechanical Properties and Micromorphology of Calcium Cements Exposed to Polyacrylic and Phosphoric Acids.

    PubMed

    de Souza, Gustavo Fernandes; Arrais, Ana Beatriz; Aragão, Cícero Flávio Soares; Ferreira, Isana Alvares; Borges, Boniek Castillo Dutra

    2018-01-01

    To evaluate if physical and mechanical properties of self-curing calcium hydroxide cements were affected by contact with polyacrylic and phosphoric acids. Resin-containing (Life (LF)) and resin-free (Hydro C (HyC)) materials were subjected to polyacrylic acid conditioning and rinsing (POL); phosphoric acid conditioning and rinsing (PHO); rinsing only; and no treatment ( n = 10). Water sorption/solubility, release of hydroxyl ions (pH), roughness (Ra), and impact resistance were evaluated. Additional samples ( n = 1) were prepared for scanning electron microscopy (SEM) analysis of the surface morphology. Data were analyzed by two-way ANOVA and Tukey post hoc test ( P < 0.05). Water sorption was significantly higher for LF when in contact with PHO and lower for POL ( P < 0.05). The mean solubility was higher with POL for both cements ( P < 0.05). PHO increased the mean surface roughness for HyC ( P < 0.01); a significant decrease was noted for LF after contact with both acids ( P < 0.01). PHO promoted lower release of hydroxyl ions on both cements ( P < 0.05). For LF, rinsing, PHO, and POL presented similar morphology, differing from the control group. For HyC, PHO and POL presented similar morphology, differing from the control group. PHO had a negative effect on the physical properties of the cements tested, except for the solubility test. POL affected roughness and solubility of HyC cement. Clinical procedures that require polyacrylic and phosphoric acid conditioning must be done carefully on self-curing calcium hydroxide cements in order to avoid negative impact on their properties.

  17. Variable Temperature Infrared Spectroscopy Investigations of Benzoic Acid Desorption from Sodium and Calcium Montmorillonite Clays.

    PubMed

    Nickels, Tara M; Ingram, Audrey L; Maraoulaite, Dalia K; White, Robert L

    2015-12-01

    Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate.

  18. Calcium Free Asbestos for Fuel Cells

    NASA Technical Reports Server (NTRS)

    Snitzer, B. A.

    1983-01-01

    Organic-acid salt removes unwanted calcium without weakening asbestos. Asbestos mixed with disodium ethylene diamine tetraacetic acid (disodium EDTA) in water and agitated for 2 hours. After disodium EDTA solution is drained away, asbestos contains only 0.02 to 0.1 percent calcium. Fiber structure of asbestos unaffected.

  19. Higher Dietary Acidity is Associated with Lower Bone Mineral Density in Postmenopausal Iranian Women, Independent of Dietary Calcium Intake.

    PubMed

    Shariati-Bafghi, Seyedeh-Elaheh; Nosrat-Mirshekarlou, Elaheh; Karamati, Mohsen; Rashidkhani, Bahram

    2014-01-01

    Findings of studies on the link between dietary acid-base balance and bone mass are relatively mixed. We examined the association between dietary acid-base balance and bone mineral density (BMD) in a sample of Iranian women, hypothesizing that a higher dietary acidity would be inversely associated with BMD, even when dietary calcium intake is adequate. In this cross-sectional study, lumbar spine and femoral neck BMDs of 151 postmenopausal women aged 50-85 years were measured using dual-energy x-ray absorptiometry. Dietary intakes were assessed using a validated food frequency questionnaire. Renal net acid excretion (RNAE), an estimate of acid-base balance, was then calculated indirectly from the diet using the formulae of Remer (based on dietary intakes of protein, phosphorus, potassium, and magnesium; RNAERemer) and Frassetto (based on dietary intakes of protein and potassium; RNAEFrassetto), and was energy adjusted by the residual method. After adjusting for potential confounders, multivariable adjusted means of the lumbar spine BMD of women in the highest tertiles of RNAERemer and RNAEFrassetto were significantly lower than those in the lowest tertiles (for RNAERemer: mean difference -0.084 g/cm2; P=0.007 and for RNAEFrassetto: mean difference -0.088 g/cm2; P=0.004). Similar results were observed in a subgroup analysis of subjects with dietary calcium intake of >800 mg/day. In conclusion, a higher RNAE (i. e. more dietary acidity), which is associated with greater intake of acid-generating foods and lower intake of alkali-generating foods, may be involved in deteriorating the bone health of postmenopausal Iranian women, even in the context of adequate dietary calcium intake.

  20. Intracellular sphingosine releases calcium from lysosomes.

    PubMed

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

    2015-11-27

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC.

  1. Calcification prevention tablets

    NASA Technical Reports Server (NTRS)

    Lindsay, Geoffrey A.; Hasting, Michael A.; Gustavson, Michael A.

    1991-01-01

    Citric acid tablets, which slowly release citric acid when flushed with water, are under development by the Navy for calcification prevention. The citric acid dissolves calcium carbonate deposits and chelates the calcium. For use in urinals, a dispenser is not required because the tablets are non-toxic and safe to handle. The tablets are placed in the bottom of the urinal, and are consumed in several hundred flushes (the release rate can be tailored by adjusting the formulation). All of the ingredients are environmentally biodegradable. Mass production of the tablets on commercial tableting machines was demonstrated. The tablets are inexpensive (about 75 cents apiece). Incidences of clogged pipes and urinals were greatly decreased in long term shipboard tests. The corrosion rate of sewage collection pipe (90/10 Cu/Ni) in citric acid solution in the laboratory is several mils per year at conditions typically found in traps under the urinals. The only shipboard corrosion seen to date is of the yellow brass urinal tail pieces. While this is acceptable, the search for a nontoxic corrosion inhibitor is underway. The shelf life of the tablets is at least one year if stored at 50 percent relative humidity, and longer if stored in sealed plastic buckets.

  2. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae...

  3. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae...

  4. Fluoride toothpaste containing 1.5% arginine and insoluble calcium as a new standard of care in caries prevention.

    PubMed

    ten Cate, J M; Cummins, D

    2013-01-01

    In spite of obvious achievements in prevention, caries remains a prevalent disease. Fluorides are effective by inhibiting enamel and dentin demineralization and enhancing remineralization, but have little or no influence on bacterial processes in dental plaque. Dental caries is a continuum of stages from reversible, early lesions to irreversible, pre-cavitated lesions and, ultimately, to cavities. Prevention should focus on strengthening protective and reducing pathological factors, and careful monitoring of the disease state. While fluoride and the mineral aspects of caries have been in focus for decades, new insights into the etiology of caries have generated novel concepts and approaches to its prevention and treatment. The observation that some plaque bacteria can produce alkali metabolites and, thus, raise pH or neutralize acid formed in plaque has long been known. Such pH rise factors are related to caries susceptibility. Nourishing the plaque with substrates that encourage alkali-producing reactions is a protective factor in the caries continuum. This article reviews the results of clinical studies with a novel toothpaste containing 1.5% arginine, an insoluble calcium compound, and fluoride which have demonstrated superior remineralization of white spot enamel lesions and rehardening of root surface lesions, favorable effects on the de-/remineralization balance, as well as superior cavity prevention efficacy compared to toothpaste with fluoride alone. Studies have also confirmed formation of ammonia and elevated pH levels in subjects using the arginine-containing toothpaste. This novel toothpaste effectively combines the established effects of fluoride on de- and remineralization with reduction of caries-inducing pathological factors resulting from plaque metabolism.

  5. Effect of adding acid solution on setting time and compressive strength of high calcium fly ash based geopolymer

    NASA Astrophysics Data System (ADS)

    Antoni, Herianto, Jason Ghorman; Anastasia, Evelin; Hardjito, Djwantoro

    2017-09-01

    Fly ash with high calcium oxide content when used as the base material in geopolymer concrete could cause flash setting or rapid hardening. However, it might increase the compressive strength of geopolymer concrete. This rapid hardening could cause problems if the geopolymer concrete is used on a large scale casting that requires a long setting time. CaO content can be indicated by pH values of the fly ash, while higher pH is correlated with the rapid setting time of fly ash-based geopolymer. This study investigates the addition of acid solution to reduce the initial pH of the fly ash and to prolong the setting time of the mixture. The acids used in this study are hydrochloric acid (HCl), sulfuric acid (H2 SO4), nitric acid (HNO3) and acetic acid (CH3 COOH). It was found that the addition of acid solution in fly ash was able to decrease the initial pH of fly ash, however, the initial setting time of geopolymer was not reduced. It was even faster than that of the control mixture. The acid type causes various influence, depending on the fly ash properties. In addition, the use of acid solution in fly ash reduces the compressive strength of geopolymer mortar. It is concluded that the addition of acid solution cannot prolong the rapid hardening of high calcium fly ash geopolymer, and it causes adverse effect on the compressive strength.

  6. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ([CH2OH(CHOH)4COO]2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by...

  7. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ([CH2OH(CHOH)4COO]2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by...

  8. Effect of curd washing on the properties of reduced-calcium and standard-calcium Cheddar cheese.

    PubMed

    Hou, Jia; McSweeney, Paul L H; Beresford, Thomas P; Guinee, Timothy P

    2014-10-01

    Washed (W) and nonwashed (NW) variants of standard (SCa) and reduced-calcium (RCa) Cheddar cheeses were made in triplicate, ripened for a 270-d period, and analyzed for composition and changes during maturation. Curd washing was applied to cheeses to give a target level of lactose plus lactic acid in cheese moisture of 3.9 g/100 g in the W cheese, compared with a value of 5.3 g/100 g of lactose plus lactic acid in cheese moisture in the control NW cheeses. The 4 cheese types were denoted standard calcium nonwashed (SCaNW), standard calcium washed (SCaW), reduced-calcium nonwashed (RCaNW), and reduced-calcium washed (RCaW). The mean calcium level was 760 mg/100 g in the SCaNW and SCaW and 660 mg/100 g in the RCaNW and RCaW cheeses. Otherwise the gross composition of all cheeses was similar, each with protein, fat, and moisture levels of ~26, 32, and 36 g/100 g, respectively. Curd washing significantly reduced the mean level of lactic acid in the SCaW cheese and residual lactose in both SCaW and RCaW cheeses. The mean pH of the standard-calcium cheese over the 270-d ripening period increased significantly with curd washing and ripening time, in contrast to the reduced-calcium cheese, which was not affected by the latter parameters. Otherwise curd washing had little effect on changes in populations of starter bacteria or nonstarter lactic acid bacteria, proteolysis, rheology, or color of the cheese during ripening. Descriptive sensory analysis at 270 d indicated that the SCaW cheese had a nuttier, sweeter, less fruity, and less rancid taste than the corresponding SCaNW cheese. In contrast, curd washing was not as effective in discriminating between the RCaW and RCaNW cheeses. The RCaW cheese had a more buttery, caramel odor and flavor, and a more bitter, less sweet, and nutty taste than the SCaW cheese, whereas the RCaNW had a more pungent and less fruity flavor, a less fruity odor, a saltier, more-bitter, and less acidic taste, and a more astringent mouthfeel than

  9. Efficacy of sodium hypochlorite, ethylenediaminetetraacetic acid, citric acid and phosphoric acid in calcium hydroxide removal from the root canal: a microscopic cleanliness evaluation.

    PubMed

    da Silva, Juliana Melo; Silveira, Amanda; Santos, Elizandra; Prado, Laiìs; Pessoa, Oscar F

    2011-12-01

    Rooted molars were subjected to standardized canal instrumentation to a master apical file (MAF). The samples were dressed with Ca(OH)(2), and after 7 days, teeth were reopened and Ca(OH)(2) medication was removed by 1 of 4 different experimental procedures: 2.5% sodium hypochlorite (NaOCl) (n = 10); 17% EDTA-T (n = 10); 10% citric acid (n = 10); or 37% phosphoric acid (n = 10). This was followed by reinstrumentation with MAF plus 15 mL saline solution. The roots were prepared for scanning electron microscopic analysis of the cervical, middle, and apical thirds. Statistical analysis was performed with the Kruskal-Wallis test. EDTA-T and phosphoric acid gave the best results in the apical third, with significant statistical differences compared with other groups. NaOCl gave the worst results. Irrigation with 17% EDTA-T and 37% phosphoric acid is more effective than sodium hypochlorite and citric acid in the removal of calcium hydroxide from the apical third. Copyright © 2011 Mosby, Inc. All rights reserved.

  10. Prophylactic oral calcium supplementation therapy to prevent early post thyroidectomy hypocalcemia and evaluation of postoperative parathyroid hormone levels to detect hypocalcemia: A prospective randomized study.

    PubMed

    Arer, Ilker Murat; Kus, Murat; Akkapulu, Nezih; Aytac, Huseyin Ozgur; Yabanoglu, Hakan; Caliskan, Kenan; Tarim, Mehmet Akin

    2017-02-01

    Postoperative hypocalcemia is the most common complication after total thyroidectomy. Postoperative parathyroid hormone (PTH) measurement is one of the methods to detect or prevent postoperative hypocalcemia. Prophylactic oral calcium supplementation is another method to prevent early postoperative hypocalcemia. The aim of this study is to detect the accurate timing of PTH and evaluate efficacy of routine oral calcium supplementation for postoperative hypocalcemia. A total of 106 patients were performed total thyroidectomy. Rotuine oral calcium supplementation was given to group 1 and no treatment to group 2 according to randomization. Serum calcium and PTH level of patients in group 2 at postoperative 6, 12 and 24 h and patients in both groups at postoperative day 7 were evaluated. Patients were compared according to age, sex, operation findings, serum calcium and PTH levels and symptomatic hypocalcemia. Half of the patients (50%) were in group 1. Most of the patients were female (83%). The most common etiology of thyroid disease was multinodular goiter (64.1%). Oral calcium supplementation was given to 18 (33.9%) patients in group 2. Symptomatic hypocalcemia for group 1 and 2 was found to be 1.9 and 33.9% respectively (p < 0.05). No statistical difference can be observed regarding the timing of serum biomarkers. Serum PTH levels at postoperative 12 and 24 h can predict early post-thyroidectomy hypocalcemia. Prophylactic oral calcium supplementation therapy can prevent early post-thyroidectomy hypocalcemia with advantages of being cost effective and safe. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

  11. Comparative transcriptome analysis reveals different molecular mechanisms of Bacillus coagulans 2-6 response to sodium lactate and calcium lactate during lactic acid production.

    PubMed

    Qin, Jiayang; Wang, Xiuwen; Wang, Landong; Zhu, Beibei; Zhang, Xiaohua; Yao, Qingshou; Xu, Ping

    2015-01-01

    Lactate production is enhanced by adding calcium carbonate or sodium hydroxide during fermentation. However, Bacillus coagulans 2-6 can produce more than 180 g/L L-lactic acid when calcium lactate is accumulated, but less than 120 g/L L-lactic acid when sodium lactate is formed. The molecular mechanisms by which B. coagulans responds to calcium lactate and sodium lactate remain unclear. In this study, comparative transcriptomic methods based on high-throughput RNA sequencing were applied to study gene expression changes in B. coagulans 2-6 cultured in non-stress, sodium lactate stress and calcium lactate stress conditions. Gene expression profiling identified 712 and 1213 significantly regulated genes in response to calcium lactate stress and sodium lactate stress, respectively. Gene ontology assignments of the differentially expressed genes were performed. KEGG pathway enrichment analysis revealed that 'ATP-binding cassette transporters' were significantly affected by calcium lactate stress, and 'amino sugar and nucleotide sugar metabolism' was significantly affected by sodium lactate stress. It was also found that lactate fermentation was less affected by calcium lactate stress than by sodium lactate stress. Sodium lactate stress had negative effect on the expression of 'glycolysis/gluconeogenesis' genes but positive effect on the expression of 'citrate cycle (TCA cycle)' genes. However, calcium lactate stress had positive influence on the expression of 'glycolysis/gluconeogenesis' genes and had minor influence on 'citrate cycle (TCA cycle)' genes. Thus, our findings offer new insights into the responses of B. coagulans to different lactate stresses. Notably, our RNA-seq dataset constitute a robust database for investigating the functions of genes induced by lactate stress in the future and identify potential targets for genetic engineering to further improve L-lactic acid production by B. coagulans.

  12. Comparative Transcriptome Analysis Reveals Different Molecular Mechanisms of Bacillus coagulans 2-6 Response to Sodium Lactate and Calcium Lactate during Lactic Acid Production

    PubMed Central

    Qin, Jiayang; Wang, Xiuwen; Wang, Landong; Zhu, Beibei; Zhang, Xiaohua; Yao, Qingshou; Xu, Ping

    2015-01-01

    Lactate production is enhanced by adding calcium carbonate or sodium hydroxide during fermentation. However, Bacillus coagulans 2-6 can produce more than 180 g/L L-lactic acid when calcium lactate is accumulated, but less than 120 g/L L-lactic acid when sodium lactate is formed. The molecular mechanisms by which B. coagulans responds to calcium lactate and sodium lactate remain unclear. In this study, comparative transcriptomic methods based on high-throughput RNA sequencing were applied to study gene expression changes in B. coagulans 2-6 cultured in non-stress, sodium lactate stress and calcium lactate stress conditions. Gene expression profiling identified 712 and 1213 significantly regulated genes in response to calcium lactate stress and sodium lactate stress, respectively. Gene ontology assignments of the differentially expressed genes were performed. KEGG pathway enrichment analysis revealed that ‘ATP-binding cassette transporters’ were significantly affected by calcium lactate stress, and ‘amino sugar and nucleotide sugar metabolism’ was significantly affected by sodium lactate stress. It was also found that lactate fermentation was less affected by calcium lactate stress than by sodium lactate stress. Sodium lactate stress had negative effect on the expression of ‘glycolysis/gluconeogenesis’ genes but positive effect on the expression of ‘citrate cycle (TCA cycle)’ genes. However, calcium lactate stress had positive influence on the expression of ‘glycolysis/gluconeogenesis’ genes and had minor influence on ‘citrate cycle (TCA cycle)’ genes. Thus, our findings offer new insights into the responses of B. coagulans to different lactate stresses. Notably, our RNA-seq dataset constitute a robust database for investigating the functions of genes induced by lactate stress in the future and identify potential targets for genetic engineering to further improve L-lactic acid production by B. coagulans. PMID:25875592

  13. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium propionate. 184.1221 Section 184.1221 Food... Specific Substances Affirmed as GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or a...

  14. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium propionate. 184.1221 Section 184.1221 Food... Specific Substances Affirmed as GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or a...

  15. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium propionate. 184.1221 Section 184.1221 Food... GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or a crystalline solid, possessing not more...

  16. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium stearate. 184.1229 Section 184.1229 Food... GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as a white precipitate by mixing...

  17. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium propionate. 184.1221 Section 184.1221 Food... Specific Substances Affirmed as GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or a...

  18. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium propionate. 184.1221 Section 184.1221 Food... Specific Substances Affirmed as GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or a...

  19. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as...

  20. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as...

  1. Is calcium excess in western diet a major cause of arterial disease?

    PubMed

    Seely, S

    1991-11-01

    The daily requirement of a young adult for calcium is 300-400 mg, the quantity consumed in many third-world countries. The dietary intake can be doubled or trebled by consumption of milk, thus half a litre of milk, consumed by many individuals daily in prosperous countries, adds 600 mg. The need for calcium is greatly reduced in old age, so that the excess from a given intake becomes more pronounced. The potential hazard of a high intake is that a small fraction finds its way into soft tissues. The aorta is notably prone to calcification, resulting in loss of elasticity. The aorta and its large branches constitute an elastic reservoir, distended during systole and contracting in diastole. This contraction provides the energy for the maintenance of diastolic pressure, which decreases with the deterioration of elasticity and needs a continually increasing systolic pressure to restore its normal value. The heart is disadvantaged in two ways. Its work is increased by having to eject the systolic volume into a stiffer reservoir, and the diastolic filling of the coronary arteries is reduced. This is the main cause of hypertension in old age--there is no increase in blood pressure with age in undeveloped countries where intake of calcium is low. The best cure would be prevention: the reduction of intake of calcium in prosperous countries. Failing that, phytic acid is suggested as the best calcium antagonist. Phytic acid, a natural product present in grains, converts dietary calcium into insoluble phosphates which pass unabsorbed through the digestive tract. The presently used calcium antagonists are not so satisfactory.

  2. Intracellular sphingosine releases calcium from lysosomes

    PubMed Central

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

    2015-01-01

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC. DOI: http://dx.doi.org/10.7554/eLife.10616.001 PMID:26613410

  3. Synthesis of size-controlled acid-resistant hybrid calcium carbonate microparticles as templates for fabricating "micelles-enhanced" polyelectrolyte capsules by the LBL technique.

    PubMed

    Li, Xiaodong; Hu, Qiaoling; Yue, Linhai; Shen, Jiacong

    2006-07-24

    Size-controlled, low-dispersed calcium carbonate microparticles were synthesized in the presence of the amphiphilic block copolymer polystyrene-b-poly(acrylic acid) (PS-b-PAA) by modulating the concentration of block copolymer in the reactive system. This type of hybrid microparticles have acid-resistant properties. By investigating the aggregation behaviors of PS-b-PAA micelles by transmission electron microscopy (TEM), the mechanism of hybrid calcium carbonate formation illustrated that the block copolymer served not only as "pseudonuclei" for the growth of calcium carbonate nanocrystals, but also forms the supramicelle congeries, a spherical framework, as templates for calcium carbonate nanocrystal growth into hybrid CaCO(3) particles. Moreover, this pilot study shows that the hybrid microparticle is a novel candidate as a template for fabricating multilayer polyelectrolyte capsules, in which the block copolymer is retained within the capsule interior after core removal under soft conditions. This not only facilitates the encapsulation of special materials, but also provides "micelles-enhanced" polyelectrolyte capsules.

  4. In vivo evaluation of teicoplanin- and calcium sulfate-loaded PMMA bone cement in preventing implant-related osteomyelitis in rats.

    PubMed

    Tuzuner, T; Sencan, I; Ozdemir, D; Alper, M; Duman, S; Yavuz, T; Yildirim, M

    2006-12-01

    The objective of this study was to evaluate the efficacy of teicoplanin- and calcium sulphate-loaded polymethylmethacrylate (PMMA) bone cements in preventing experimental implant-related osteomyelitis in rats. Four groups of antibiotic-loaded rods were prepared and were implanted into the lateral condylus of the rat femur after inoculation of Staphylococcus aureus. The effectiveness of these were assessed microbiologically, radiographically, and histopathologically. Radiographic evaluation revealed a significant reduction of periostal reaction and osteolysis in rats that received calcium sulphate- and teicoplanin-loaded rods. Histopathological evaluation confirmed these results. Acute infection and bone necrosis were found to be significantly lower in rats that had received calcium sulphate- and teicoplanin-loaded rods. The addition of calcium sulfate to teicoplanin-loaded PMMA bone cement appeared satisfactory as an antibiotic-carrying system for prophylaxis of experimental implant-related osteomyelitis, but further investigations are needed to reach definitive statements for clinical applications.

  5. Folic acid and birth defect prevention

    MedlinePlus

    Preconceptional counseling. In: Cunningham FG, Leveno KL, Bloom SL, et al, eds. Williams Obstetrics. 24th ed. New York, NY: McGraw-Hill; 2014:chap 8. US Preventive Services Task Force. Folic acid for ...

  6. The effect of ascorbic acid ingestion on the biochemical and physicochemical risk factors associated with calcium oxalate kidney stone formation.

    PubMed

    Auer, B L; Auer, D; Rodgers, A L

    1998-03-01

    The present study was undertaken to determine the effect of ingestion of large doses of vitamin C on urinary oxalate excretion and on a number of other biochemical and physicochemical risk factors associated with calcium oxalate urolithiasis. A further objective was to determine urinary ascorbate excretion and to relate it qualitatively to ingested levels of the vitamin and oxalate excretion. Ten healthy males participated in a protocol in which 4 g ascorbic acid was ingested for 5 days. Urines (24 h) were collected prior to, during and after the protocol. The urine collection procedure was designed to allow for the analysis of oxalate in the presence and absence of an EDTA preservative and for the analysis of ascorbic acid by manual titration using 2,6 dichlorophenolindophenol. Physicochemical risk factors such as the calcium oxalate relative supersaturation and Tiselius risk index were calculated from urine composition. The results showed that erroneously high analytical oxalate levels occur in the asence of preservative. In the preserved samples there was no significant increase in oxalate excretion at any stage of the protocol. Ascorbate excretion increased when vitamin C ingestion commenced but levelled out after 24 hours suggesting that saturation of the metabolic pool is reached within 24 hours after which ingested ascorbic acid is excreted unmetabolized in the urine. While transient statistically significant changes occurred in some of the biochemical risk factors, they were not regarded as being clinically significant. There were no changes in either the calcium oxalate relative supersaturation or Tiselius risk index. It is concluded that ingestion of large doses of ascorbic acid does not affect the principal risk factors associated with calcium oxalate kidney stone formation.

  7. Differential intracellular calcium influx, nitric oxide production, ICAM-1 and IL8 expression in primary bovine endothelial cells exposed to nonesterified fatty acids.

    PubMed

    Loaiza, Anitsi; Carretta, María D; Taubert, Anja; Hermosilla, Carlos; Hidalgo, María A; Burgos, Rafael A

    2016-02-25

    Nonesterified fatty acids (NEFAs) are involved in proinflammatory processes in cattle, including in the increased expression of adhesion molecules in endothelial cells. However, the mechanisms underlying these effects are still unknown. The aim of this study was to assess the effects of NEFAs on the intracellular calcium (Ca(2+) i) influx, nitric oxide production, and ICAM-1 and IL-8 expression in primary bovine umbilical vein endothelial cells (BUVECs). Myristic (MA), palmitic (PA), stearic (SA), oleic (OA) and linoleic acid (LA) rapidly increased Ca(2+) i. The calcium response to all tested NEFAs showed an extracellular calcium dependence and only the LA response was significantly inhibited until the intracellular calcium was chelated. The EC50 values for MA and LA were 125 μM and 37 μM, respectively, and the MA and LA effects were dependent on calcium release from the endoplasmic reticulum stores and on the L-type calcium channels. Only the calcium response to MA was significantly reduced by GW1100, a selective G-protein-coupled free fatty acid receptor (GPR40) antagonist. We also detected a functional FFAR1/GPR40 protein in BUVECs by using western blotting and the FFAR1/GPR40 agonist TAK-875. Only LA increased the cellular nitric oxide levels in a calcium-dependent manner. LA stimulation but not MA stimulation increased ICAM-1 and IL-8-expression in BUVECs. This effect was inhibited by GW1100, an antagonist of FFAR1/GPR40, but not by U-73122, a phospholipase C inhibitor. These findings strongly suggest that each individual NEFA stimulates endothelial cells in a different way, with clearly different effects on intracellular calcium mobilization, NO production, and IL-8 and ICAM-1 expression in primary BUVECs. These findings not only extend our understanding of NEFA-mediated diseases in ruminants, but also provide new insight into the different molecular mechanisms involved during endothelial cell activation by NEFAs.

  8. 21 CFR 184.1195 - Calcium citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... Specific Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric...

  9. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... Specific Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It...

  10. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the...

  11. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium acetate. 184.1185 Section 184.1185 Food... Specific Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It...

  12. Molecular models of alginic acid: Interactions with calcium ions and calcite surfaces

    NASA Astrophysics Data System (ADS)

    Perry, Thomas D.; Cygan, Randall T.; Mitchell, Ralph

    2006-07-01

    Cation binding by polysaccharides is observed in many environments and is important for predictive environmental modeling, and numerous industrial and food technology applications. The complexities of these cation-organic interactions are well suited for predictive molecular modeling and the analysis of conformation and configuration of polysaccharides and their influence on cation binding. In this study, alginic acid was chosen as a model polymer system and representative disaccharide and polysaccharide subunits were developed. Molecular dynamics simulation of the torsion angles of the ether linkage between various monomeric subunits identified local and global energy minima for selected disaccharides. The simulations indicate stable disaccharide configurations and a common global energy minimum for all disaccharide models at Φ = 274 ± 7°, Ψ = 227 ± 5°, where Φ and Ψ are the torsion angles about the ether linkage. The ability of disaccharide subunits to bind calcium ions and to associate with the (101¯4) surface of calcite was also investigated. Molecular models of disaccharide interactions with calcite provide binding energy differences for conformations that are related to the proximity and residence densities of the electron-donating moieties with calcium ions on the calcite surface, which are controlled, in part, by the torsion of the ether linkage between monosaccharide units. Dynamically optimized configurations for polymer alginate models with calcium ions were also derived.

  13. Serum uric acid level is an independent risk factor for presence of calcium in coronary arteries: an observational case-controlled study.

    PubMed

    Atar, Aslı Inci; Yılmaz, Omer Cağlar; Akın, Kayıhan; Selçoki, Yusuf; Er, Okan; Eryonucu, Beyhan

    2013-03-01

    A link between uric acid levels and cardiovascular diseases has been previously reported. Coronary artery calcium score (CACS) is a marker of atherosclerotic disease and a predictor of cardiovascular events. We sought to determine if serum uric acid level is an independent risk factor for the presence of calcium in coronary arteries. Four hundred and forty-two patients who were evaluated in the cardiology outpatient clinic for suspected coronary heart disease with a low-moderate risk for coronary artery disease were included in this observational case-controlled study. Serum uric acid levels were measured with colorimetric methods. CACS were performed using a 64-slice CT scanner. Patients were divided to 3 groups according to their CACS value (Group 1: CACS=0, Group 2: CACS 1-100, Group 3: CACS>100). The demographical characteristics and laboratory findings of 3 groups were similar, except age, fasting glucose levels and serum uric acid levels. Serum uric acid levels were found to increase significantly with increasing CACS (p=0.001). Patients were grouped according to presence CAC (CACS=0 and CACS≥1) and in the multiple regression analysis, age (OR, 1.11, 95% CI, 1.07-1.16), smoking (OR, 3.83, 95% CI, 2.06-7.09), serum uric acid levels (OR, 1.26, 95% CI, 1.04-1.54) and average 10-year total risk of Framingham risk score (OR, 1.13, 95% CI, 1.04-1.09) appeared as independent factors predictive of presence of CAC (p<0.05). Serum uric acid level is an independent risk factor for presence of coronary calcium. Moreover, increasing levels of serum uric acid are associated with increasing CACS.

  14. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

  15. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

  16. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

  17. Effect of Potassium Citrate on Calcium Phosphate Stones in a Model of Hypercalciuria

    PubMed Central

    Asplin, John R.; Frick, Kevin K.; Granja, Ignacio; Culbertson, Christopher D.; Ng, Adeline; Grynpas, Marc D.; Bushinsky, David A.

    2015-01-01

    Potassium citrate is prescribed to decrease stone recurrence in patients with calcium nephrolithiasis. Citrate binds intestinal and urine calcium and increases urine pH. Citrate, metabolized to bicarbonate, should decrease calcium excretion by reducing bone resorption and increasing renal calcium reabsorption. However, citrate binding to intestinal calcium may increase absorption and renal excretion of both phosphate and oxalate. Thus, the effect of potassium citrate on urine calcium oxalate and calcium phosphate supersaturation and stone formation is complex and difficult to predict. To study the effects of potassium citrate on urine supersaturation and stone formation, we utilized 95th-generation inbred genetic hypercalciuric stone-forming rats. Rats were fed a fixed amount of a normal calcium (1.2%) diet supplemented with potassium citrate or potassium chloride (each 4 mmol/d) for 18 weeks. Urine was collected at 6, 12, and 18 weeks. At 18 weeks, stone formation was visualized by radiography. Urine citrate, phosphate, oxalate, and pH levels were higher and urine calcium level was lower in rats fed potassium citrate. Furthermore, calcium oxalate and calcium phosphate supersaturation were higher with potassium citrate; however, uric acid supersaturation was lower. Both groups had similar numbers of exclusively calcium phosphate stones. Thus, potassium citrate effectively raises urine citrate levels and lowers urine calcium levels; however, the increases in urine pH, oxalate, and phosphate levels lead to increased calcium oxalate and calcium phosphate supersaturation. Potassium citrate induces complex changes in urine chemistries and resultant supersaturation, which may not be beneficial in preventing calcium phosphate stone formation. PMID:25855777

  18. Prevention of ventricular arrhythmia and calcium dysregulation in a catecholaminergic polymorphic ventricular tachycardia mouse model carrying calsequestrin-2 mutation.

    PubMed

    Alcalai, Ronny; Wakimoto, Hiroko; Arad, Michael; Planer, David; Konno, Tetsuo; Wang, Libin; Seidman, Jon G; Seidman, Christine E; Berul, Charles I

    2011-03-01

    Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial arrhythmic syndrome caused by mutations in genes encoding the calcium-regulation proteins cardiac ryanodine receptor (RyR2) or calsequestrin-2 (CASQ2). Mechanistic studies indicate that CPVT is mediated by diastolic Ca(2+) overload and increased Ca(2+) leak through the RyR2 channel, implying that treatment targeting these defects might be efficacious in CPVT. CPVT mouse models that lack CASQ2 were treated with Ca(2+) -channel inhibitors, β-adrenergic inhibitors, or Mg(2+) . Treatment effects on ventricular arrhythmia, sarcoplasmic reticulum (SR) protein expression and Ca(2+) transients of isolated myocytes were assessed. Each study agent reduced the frequency of stress-induced ventricular arrhythmia in mutant mice. The Ca(2+) channel blocker verapamil was most efficacious and completely prevented arrhythmia in 85% of mice. Verapamil significantly increased the SR Ca(2+) content in mutant myocytes, diminished diastolic Ca(2+) overload, increased systolic Ca(2+) amplitude, and prevented Ca(2+) oscillations in stressed mutant myocytes. Ca(2+) channel inhibition by verapamil rectified abnormal calcium handling in CPVT myocytes and prevented ventricular arrhythmias. Verapamil-induced partial normalization of SR Ca(2+) content in mutant myocytes implicates CASQ2 as modulator of RyR2 activity, rather than or in addition to, Ca(2+) buffer protein. Agents such as verapamil that attenuate cardiomyocyte calcium overload are appropriate for assessing clinical efficacy in human CPVT. © 2010 Wiley Periodicals, Inc.

  19. Prevention of Ventricular Arrhythmia and Calcium Dysregulation in a Catecholaminergic Polymorphic Ventricular Tachycardia Mouse Model Carrying Calsequestrin-2 Mutation

    PubMed Central

    Alcalai, Ronny; Wakimoto, Hiroko; Arad, Michael; Planer, David; Konno, Tetsuo; Wang, Libin; Seidman, Jon G.; Seidman, Christine E.; Berul, Charles I

    2010-01-01

    Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial arrhythmic syndrome caused by mutations in genes encoding the calcium-regulation proteins cardiac ryanodine receptor (RyR2) or calsequestrin-2 (CASQ2). Mechanistic studies indicate that CPVT is mediated by diastolic Ca2+ overload and increased Ca2+ leak through the RyR2 channel, implying that treatment targeting these defects might be efficacious in CPVT. Method and results CPVT mouse models that lack CASQ2 were treated with Ca2+-channel inhibitors, β-adrenergic inhibitors, or Mg2+. Treatment effects on ventricular arrhythmia, sarcoplasmic reticulum (SR) protein expression and Ca2+ transients of isolated myocytes were assessed. Each study agent reduced the frequency of stress-induced ventricular arrhythmia in mutant mice. The Ca2+ channel blocker verapamil was most efficacious and completely prevented arrhythmia in 85% of mice. Verapamil significantly increased the SR Ca2+ content in mutant myocytes, diminished diastolic Ca2+ overload, increased systolic Ca2+ amplitude, and prevented Ca2+ oscillations in stressed mutant myocytes. Conclusions Ca2+ channel inhibition by verapamil rectified abnormal calcium handling in CPVT myocytes and prevented ventricular arrhythmias. Verapamil-induced partial normalization of SR Ca2+ content in mutant myocytes implicates CASQ2 as modulator of RyR2 activity, rather than or in addition to, Ca2+ buffer protein. Agents such as verapamil that attenuate cardiomyocyte calcium overload are appropriate for assessing clinical efficacy in human CPVT. PMID:20807279

  20. Calcium intake and mortality from all causes, cancer, and cardiovascular disease: the Cancer Prevention Study II Nutrition Cohort.

    PubMed

    Yang, Baiyu; Campbell, Peter T; Gapstur, Susan M; Jacobs, Eric J; Bostick, Roberd M; Fedirko, Veronika; Flanders, W Dana; McCullough, Marjorie L

    2016-03-01

    Calcium intake may be important for bone health, but its effects on other outcomes, including cardiovascular disease (CVD) and cancer, remain unclear. Recent reports of adverse cardiovascular effects of supplemental calcium have raised concerns. We investigated associations of supplemental, dietary, and total calcium intakes with all-cause, CVD-specific, and cancer-specific mortality in a large, prospective cohort. A total of 132,823 participants in the Cancer Prevention Study II Nutrition Cohort, who were followed from baseline (1992 or 1993) through 2012 for mortality outcomes, were included in the analysis. Dietary and supplemental calcium information was first collected at baseline and updated in 1999 and 2003. Multivariable-adjusted Cox proportional hazards models with cumulative updating of exposures were used to calculate RRs and 95% CIs for associations between calcium intake and mortality. During a mean follow-up of 17.5 y, 43,186 deaths occurred. For men, supplemental calcium intake was overall not associated with mortality outcomes (P-trend > 0.05 for all), but men who were taking ≥1000 mg supplemental calcium/d had a higher risk of all-cause mortality (RR: 1.17; 95% CI: 1.03, 1.33), which was primarily attributed to borderline statistically significant higher risk of CVD-specific mortality (RR: 1.22; 95% CI: 0.99, 1.51). For women, supplemental calcium was inversely associated with mortality from all causes [RR (95% CI): 0.90 (0.87, 0.94), 0.84 (0.80, 0.88), and 0.93 (0.87, 0.99) for intakes of 0.1 to <500, 500 to <1000, and ≥1000 mg/d, respectively; P-trend < 0.01]. Total calcium intake was inversely associated with mortality in women (P-trend < 0.01) but not in men; dietary calcium was not associated with all-cause mortality in either sex. In this cohort, associations of calcium intake and mortality varied by sex. For women, total and supplemental calcium intakes are associated with lower mortality, whereas for men, supplemental calcium intake

  1. Exogenous Calcium Enhances the Photosystem II Photochemistry Response in Salt Stressed Tall Fescue.

    PubMed

    Wang, Guangyang; Bi, Aoyue; Amombo, Erick; Li, Huiying; Zhang, Liang; Cheng, Cheng; Hu, Tao; Fu, Jinmin

    2017-01-01

    Calcium enhances turfgrass response to salt stress. However, little is known about PSII photochemical changes when exogenous calcium was applied in salinity-stressed turfgrass. Here, we probe into the rearrangements of PSII electron transport and endogenous ion accumulation in tall fescue ( Festuca arundinacea Schreber) treated with exogenous calcium under salt stress. Three-month-old seedlings of genotype "TF133" were subjected to the control (CK), salinity (S), salinity + calcium nitrate (SC), and salinity + ethylene glycol tetraacetic acid (SE). Calcium nitrate and ethylene glycol tetraacetic acid was used as exogenous calcium donor and calcium chelating agent respectively. At the end of a 5-day duration treatment, samples in SC regime had better photochemistry performance on several parameters than salinity only. Such as the Area (equal to the plastoquinone pool size), N (number of [Formula: see text] redox turnovers until F m is reached), ψE 0 , or δRo (Efficiencdy/probability with which a PSII trapped electron is transferred from Q A to Q B or PSI acceptors), ABS/RC (Absorbed photon flux per RC). All the above suggested that calcium enhanced the electron transfer of PSII (especially beyond [Formula: see text]) and prevented reaction centers from inactivation in salt-stressed tall fescue. Furthermore, both grass shoot and root tissues generally accumulated more C, N, Ca 2+ , and K + in the SC regime than S regime. Interrelated analysis indicated that ψE 0 , δRo, ABS/RC, C, and N content in shoots was highly correlated to each other and significantly positively related to Ca 2+ and K + content in roots. Besides, high salt increased ATP6E and CAMK2 transcription level in shoot at 1 and 5 day, respectively while exogenous calcium relieved it. In root, CAMK2 level was reduced by Salinity at 5 day and exogenous calcium recovered it. These observations involved in electron transport capacity and ion accumulation assist in understanding better the protective role

  2. Exogenous Calcium Enhances the Photosystem II Photochemistry Response in Salt Stressed Tall Fescue

    PubMed Central

    Wang, Guangyang; Bi, Aoyue; Amombo, Erick; Li, Huiying; Zhang, Liang; Cheng, Cheng; Hu, Tao; Fu, Jinmin

    2017-01-01

    Calcium enhances turfgrass response to salt stress. However, little is known about PSII photochemical changes when exogenous calcium was applied in salinity-stressed turfgrass. Here, we probe into the rearrangements of PSII electron transport and endogenous ion accumulation in tall fescue (Festuca arundinacea Schreber) treated with exogenous calcium under salt stress. Three-month-old seedlings of genotype “TF133” were subjected to the control (CK), salinity (S), salinity + calcium nitrate (SC), and salinity + ethylene glycol tetraacetic acid (SE). Calcium nitrate and ethylene glycol tetraacetic acid was used as exogenous calcium donor and calcium chelating agent respectively. At the end of a 5-day duration treatment, samples in SC regime had better photochemistry performance on several parameters than salinity only. Such as the Area (equal to the plastoquinone pool size), N (number of QA- redox turnovers until Fm is reached), ψE0, or δRo (Efficiencdy/probability with which a PSII trapped electron is transferred from QA to QB or PSI acceptors), ABS/RC (Absorbed photon flux per RC). All the above suggested that calcium enhanced the electron transfer of PSII (especially beyond QA-) and prevented reaction centers from inactivation in salt-stressed tall fescue. Furthermore, both grass shoot and root tissues generally accumulated more C, N, Ca2+, and K+ in the SC regime than S regime. Interrelated analysis indicated that ψE0, δRo, ABS/RC, C, and N content in shoots was highly correlated to each other and significantly positively related to Ca2+ and K+ content in roots. Besides, high salt increased ATP6E and CAMK2 transcription level in shoot at 1 and 5 day, respectively while exogenous calcium relieved it. In root, CAMK2 level was reduced by Salinity at 5 day and exogenous calcium recovered it. These observations involved in electron transport capacity and ion accumulation assist in understanding better the protective role of exogenous calcium in tall fescue

  3. Heat stability and acid gelation properties of calcium-enriched reconstituted skim milk affected by ultrasonication.

    PubMed

    Chandrapala, Jayani; Bui, Don; Kentish, Sandra; Ashokkumar, Muthupandian

    2014-05-01

    The aggregation of proteins after heating of calcium-fortified milks has been an ongoing problem in the dairy industry. This undesirable effect restricts the manufacture of calcium rich dairy products. To overcome this problem, a completely new approach in controlling the heat stability of dairy protein solutions, developed in our lab, has been employed. In this approach, high intensity, low frequency ultrasound is applied for a very short duration after a pre-heating step at ⩾70 °C. The ultrasound breaks apart whey/whey and whey/casein aggregates through the process of acoustic cavitation. Protein aggregates do not reform on subsequent post-heating, thereby making the systems heat stable. In this paper, the acid gelation properties of ultrasonicated calcium-enriched skim milks have also been investigated. It is shown that ultrasonication alone does not change the gelation properties significantly whereas a sequence of preheating (72 °C/1 min) followed by ultrasonication leads to decreased gelation times, decreased gel syneresis and increased skim milk viscosity in comparison to heating alone. Overall, ultrasonication has the potential to provide calcium-fortified dairy products with increased heat stability. However, enhanced gelation properties can only be achieved when ultrasonication is completed in conjunction with heating.

  4. Aluminum Citrate Prevents Renal Injury from Calcium Oxalate Crystal Deposition

    PubMed Central

    Besenhofer, Lauren M.; Cain, Marie C.; Dunning, Cody

    2012-01-01

    Calcium oxalate monohydrate crystals are responsible for the kidney injury associated with exposure to ethylene glycol or severe hyperoxaluria. Current treatment strategies target the formation of calcium oxalate but not its interaction with kidney tissue. Because aluminum citrate blocks calcium oxalate binding and toxicity in human kidney cells, it may provide a different therapeutic approach to calcium oxalate-induced injury. Here, we tested the effects of aluminum citrate and sodium citrate in a Wistar rat model of acute high-dose ethylene glycol exposure. Aluminum citrate, but not sodium citrate, attenuated increases in urea nitrogen, creatinine, and the ratio of kidney to body weight in ethylene glycol–treated rats. Compared with ethylene glycol alone, the addition of aluminum citrate significantly increased the urinary excretion of both crystalline calcium and crystalline oxalate and decreased the deposition of crystals in renal tissue. In vitro, aluminum citrate interacted directly with oxalate crystals to inhibit their uptake by proximal tubule cells. These results suggest that treating with aluminum citrate attenuates renal injury in rats with severe ethylene glycol toxicity, apparently by inhibiting calcium oxalate’s interaction with, and retention by, the kidney epithelium. PMID:23138489

  5. Significance of Ca-soap formation for calcium absorption in the rat.

    PubMed Central

    Gacs, G; Barltrop, D

    1977-01-01

    The significance of calcium soap formation in the inhibition of calcium absorption has been studied in rats. 47Ca labelled soaps of fatty acids were introduced into the duodenum and the absorption of calcium measured after four hours in a whole body counter. The absorption of calcium was inversely correlated with the chain length of the fatty acid varying from 1% for Ca-stearate to 60% for Ca-hexanoate. Increasing the degree of unsaturation of the fatty acid was accompanied by increased calcium absorption. The availability of calcium for absorption from the soaps was correlated with their solubility in 1% aqueous Na-tauroglycocholate. The percentages of calcium as soap in the small intestine and the faeces after intragastric administration of calcium and fats were similar, which suggests that the faecal content of calcium soaps is an index of intestinal soap formation. Soap formation was negligible when CaCl2 was given with tristearate, triolaeate, or tridecanoate and no depression of calcium absorption was observed. Calcium absorption was markedly impaired by the addition of phosphates at a Ca/P ratio of 1:1 irrespective of the presence of neutral fats. Stearic acid resulted in significant soap formation and reduced calcium absorption. The degree of Ca-soap formation and the inhibition of calcium absorption were well correlated. The results suggest that, although calcium soap formation may markedly depress calcium absorption in the rat, no significant soap formation takes place when fats are given in the form of triglycerides. PMID:838405

  6. Modification of fatty acid profile of cow milk by calcium salts of fatty acids and its use in ice cream.

    PubMed

    Nadeem, Muhammad; Abdullah, Muhammad; Hussain, Imtiaz; Inayat, Saima

    2015-02-01

    This study was conducted to determine the effect of calcium salts of fatty acids (CSFA) on fatty acid profile of milk of "Sahiwal" cows and suitability of milk with modified fatty acids in the formulation of ice cream. Fatty acid profile of cow milk was modified by feeding CSFA to eighteen randomly stratified "Sahiwal" cows of first and early lactation divided into three groups. CSFA were offered at two different levels i.e. T1 (150 g per cow per day) T2 (300 g per cow per day) both treatments were compared with a control (T0) without any addition of calcium salts of fatty acids. Iso caloric and iso nitrogenous feeds were given to both experimental groups and control. Concentrations of short chain fatty acids in T0, T1 and T2 were 9.85 ± 0.48a, 8.8 ± 0.24b and 7.1 ± 0.37c %, respectively and the concentrations of C18:1 and C18:2 increased (P < 0.05) from 27.6 ± 1.32b % to 31.7 ± 1.68a % and 2.15 ± 0.09b % to 2.79 ± 0.05a %, respectively, at T2 level. Incorporation of milk fat of T1 and T2 (modified fatty acids profile) in ice cream did not have any adverse effect on pH, acidity and compositional attributes of ice cream. Viscosity of T1 was 67.94 ± 3.77a as compared to (T0) control 68.75 ± 2.46a (CP). Firmness of experimental samples and control were almost similar (P > 0.05) overall acceptability score of T2 was 7.1 ± 0.28b out of 9 (total score) which was more than 78 ± 2.92 %. It was concluded that CSFA may be successfully incorporated up to T2 level (300 g per cow per day) into the feed of "Sahiwal" cows to produce milk with higher content of unsaturated fatty acids and it may be used in the formulation of ice cream with acceptable sensory characteristics and increased health benefits.

  7. Optimization of Adhesive Pastes for Dental Caries Prevention.

    PubMed

    Sodata, Patteera; Juntavee, Apa; Juntavee, Niwut; Peerapattana, Jomjai

    2017-11-01

    Dental caries prevention products available on the market contain only remineralizing agents or antibacterial agents. This study aimed to develop adhesive pastes containing calcium phosphate and α-mangostin for dental caries prevention using the optimization technique. Calcium phosphate was used as a remineralizing agent, and extracted α-mangostin was used as an antibacterial agent. The effect of the independent variables, which were fumed silica, Eudragit ® EPO, polyethylene glycol, and ethyl alcohol, on the responses was investigated. The drying time, erosion rate, calcium release rate, and α-mangostin release rate were established as the measured responses. An equation and a model of the relationship were constructed. An optimal formulation was obtained, and its effect on dental caries prevention was investigated using the pH-cycling model. The quadratic equation revealed that the drying time, calcium release rate, and α-mangostin release rate tended to decrease when increasing the fumed silica and decreasing other factors. The erosion rate tended to increase when decreasing Eudragit ® EPO and increasing other factors. The observed responses of the optimal adhesive pastes were not significantly different from the predicted responses. This result demonstrated that optimization is an efficient technique in the formulation development of the adhesive pastes. In addition, the optimal adhesive pastes could enhance acid resistance activity to the tooth enamel.

  8. Is excess calcium harmful to health?

    PubMed

    Daly, Robin M; Ebeling, Peter R

    2010-05-01

    Most current guidelines recommend that older adults and the elderly strive for a total calcium intake (diet and supplements) of 1,000 to 1,300 mg/day to prevent osteoporosis and fractures. Traditionally, calcium supplements have been considered safe, effective and well tolerated, but their safety has recently been questioned due to potential adverse effects on vascular disease which may increase mortality. For example, the findings from a meta-analysis of randomized controlled trials (currently published in abstract form only) revealed that the use of calcium supplements was associated with an ~30% increased risk of myocardial infarction. If high levels of calcium are harmful to health, this may alter current public health recommendations with regard to the use of calcium supplements for preventing osteoporosis. In this review, we provide an overview of the latest information from human observational and prospective studies, randomized controlled trials and meta-analyses related to the effects of calcium supplementation on vascular disease and related risk factors, including blood pressure, lipid and lipoprotein levels and vascular calcification.

  9. Is Excess Calcium Harmful to Health?

    PubMed Central

    Daly, Robin M.; Ebeling, Peter R.

    2010-01-01

    Most current guidelines recommend that older adults and the elderly strive for a total calcium intake (diet and supplements) of 1,000 to 1,300 mg/day to prevent osteoporosis and fractures. Traditionally, calcium supplements have been considered safe, effective and well tolerated, but their safety has recently been questioned due to potential adverse effects on vascular disease which may increase mortality. For example, the findings from a meta-analysis of randomized controlled trials (currently published in abstract form only) revealed that the use of calcium supplements was associated with an ~30% increased risk of myocardial infarction. If high levels of calcium are harmful to health, this may alter current public health recommendations with regard to the use of calcium supplements for preventing osteoporosis. In this review, we provide an overview of the latest information from human observational and prospective studies, randomized controlled trials and meta-analyses related to the effects of calcium supplementation on vascular disease and related risk factors, including blood pressure, lipid and lipoprotein levels and vascular calcification. PMID:22254038

  10. Body fat loss induced by calcium in co-supplementation with conjugated linoleic acid is associated with increased expression of bone formation genes in adult mice.

    PubMed

    Chaplin, Alice; Palou, Andreu; Serra, Francisca

    2015-12-01

    The potential of conjugated linoleic acids (CLA) and calcium in weight management in animal models and human studies has been outlined, as well as their use to prevent bone loss at critical stages. In addition, it has been suggested that bone remodeling and energy metabolism are regulated by shared pathways and involve common hormones such as leptin. We have previously shown that supplementation with CLA and calcium in adult obese mice decreases body weight and body fat. The aim of the present study was to assess the effects of these two compounds on bone and energy metabolism markers on bone. Mice (C57BL/6J) were divided into five groups according to diet and treatment (up to 56 days): control (C), high-fat diet (HF), HF+CLA (CLA), HF+calcium (Ca) and HF with both compounds (CLA+Ca). At the end of treatment, bone formation markers were determined in plasma and expression of selected bone and energy markers was determined in tibia by quantitative polymerase chain reaction. Results show that CLA was associated with decreased tibia weight and minor impact on bone markers, whereas calcium, either alone or co-supplemented with CLA, maintained bone weight and promoted the expression of bone formation genes such as bone gamma-carboxyglutamate protein 2 (Bglap2) and collagen Iα1 (Col1a1). Furthermore, it had a significant effect on key players in energy metabolism, in particular leptin and adiponectin tibia receptors. Overall, in addition to the weight loss promoting properties of calcium, on its own or co-supplemented with CLA, our results support beneficial effects on bone metabolism in mice. Copyright © 2015. Published by Elsevier Inc.

  11. Dissolution mechanism of calcium apatites in acids: A review of literature

    PubMed Central

    Dorozhkin, Sergey V

    2012-01-01

    Eight dissolution models of calcium apatites (both fluorapatite and hydroxyapatite) in acids were drawn from the published literature, analyzed and discussed. Major limitations and drawbacks of the models were conversed in details. The models were shown to deal with different aspects of apatite dissolution phenomenon and none of them was able to describe the dissolution process in general. Therefore, an attempt to combine the findings obtained by different researchers was performed which resulted in creation of the general description of apatite dissolution in acids. For this purpose, eight dissolution models were assumed to complement each other and provide the correct description of the specific aspects of apatite dissolution. The general description considers all possible dissolution stages involved and points out to some missing and unclear phenomena to be experimentally studied and verified in future. This creates a new methodological approach to investigate reaction mechanisms based on sets of affine data, obtained by various research groups under dissimilar experimental conditions. PMID:25237611

  12. Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography.

    PubMed

    Maciejewska, Magdalena; Krzywania-Kaliszewska, Alicja; Zaborski, Marian

    2012-09-28

    Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor-acceptor characteristics. The dispersive components (γ(s)(D)) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor-acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79 mJ/m² and 74 mJ/m², respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γ(s)(D) was determined for nanopowders grafted with undecylenic acid, approximately 55 mJ/m². The specific interactions were characterised by the molar free energy (ΔG(A)(SP)) and molar enthalpy (ΔH(A)(SP)) of adsorption as well as the donor and acceptor interaction parameters (K(A), K(D)). Copyright © 2012 Elsevier B.V. All rights reserved.

  13. SECONDARY HYPERPARATHYROIDISM AFTER BARIATRIC SURGERY: TREATMENT IS WITH CALCIUM CARBONATE OR CALCIUM CITRATE?

    PubMed Central

    BARETTA, Giorgio Alfredo Pedroso; CAMBI, Maria Paula Carlini; RODRIGUES, Arieli Luz; MENDES, Silvana Aparecida

    2015-01-01

    Background : Bariatric surgery, especially Roux-en-Y gastric bypass, can cause serious nutritional complications arising from poor absorption of essential nutrients. Secondary hyperparathyroidism is one such complications that leads to increased parathyroid hormone levels due to a decrease in calcium and vitamin D, which may compromise bone health. Aim : To compare calcium carbonate and calcium citrate in the treatment of secondary hyperparathyroidism. Method : Patients were selected on the basis of their abnormal biochemical test and treatment was randomly done with citrate or calcium carbonate. Results : After 60 days of supplementation, biochemical tests were repeated, showing improvement in both groups. Conclusion : Supplementation with calcium (citrate or carbonate) and vitamin D is recommended after surgery for prevention of secondary hyperparathyroidism. PMID:26537273

  14. Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

    PubMed

    Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

    2014-06-01

    To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (p<0.05). In the protection study, the intrinsic rate constant for calcium loss from enamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (p<0.0001). Calcium silicate can transform into HAP and can be deposited on acid eroded and sound enamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

  15. Eicosapentaenoic acid prevents arterial calcification in klotho mutant mice.

    PubMed

    Nakamura, Kazufumi; Miura, Daiji; Saito, Yukihiro; Yunoki, Kei; Koyama, Yasushi; Satoh, Minoru; Kondo, Megumi; Osawa, Kazuhiro; Hatipoglu, Omer F; Miyoshi, Toru; Yoshida, Masashi; Morita, Hiroshi; Ito, Hiroshi

    2017-01-01

    The klotho gene was identified as an "aging-suppressor" gene that accelerates arterial calcification when disrupted. Serum and vascular klotho levels are reduced in patients with chronic kidney disease, and the reduced levels are associated with arterial calcification. Intake of eicosapentaenoic acid (EPA), an n-3 fatty acid, reduces the risk of fatal coronary artery disease. However, the effects of EPA on arterial calcification have not been fully elucidated. The aim of this study was to determine the effect of EPA on arterial calcification in klotho mutant mice. Four-week-old klotho mutant mice and wild-type (WT) mice were given a diet containing 5% EPA (EPA food, klotho and WT: n = 12, each) or not containing EPA (control food, klotho and WT: n = 12, each) for 4 weeks. Calcium volume scores of thoracic and abdominal aortas assessed by computed tomography were significantly elevated in klotho mice after 4 weeks of control food, but they were not elevated in klotho mice after EPA food or in WT mice. Serum levels of EPA and resolvin E1, an active metabolite of EPA, in EPA food-fed mice were significantly increased compared to those in control food-fed mice. An oxidative stress PCR array followed by quantitative PCR revealed that NADPH oxidase-4 (NOX4), an enzyme that generates superoxide, gene expression was up-regulated in arterial smooth muscle cells (SMCs) of klotho mice. Activity of NOX was also significantly higher in SMCs of klotho mice than in those of WT mice. EPA decreased expression levels of the NOX4 gene and NOX activity. GPR120, a receptor of n-3 fatty acids, gene knockdown by siRNA canceled effects of EPA on NOX4 gene expression and NOX activity in arterial SMCs of klotho mice. EPA prevents arterial calcification together with reduction of NOX gene expression and activity via GPR120 in klotho mutant mice.

  16. Effects of chlorogenic acid on intracellular calcium regulation in lysophosphatidylcholine-treated endothelial cells

    PubMed Central

    Jung, Hye-Jin; Im, Seung-Soon; Song, Dae-Kyu; Bae, Jae-Hoon

    2017-01-01

    Lysophosphatidylcholine (LPC) is a major phospholipid component of oxidized low-density lipoprotein (ox-LDL) and is implicated in its atherogenic activity. This study investigated the effects of LPC on cell viability, intracellular calcium homeostasis, and the protective mechanisms of chlorogenic acid (CGA) in human umbilical vein endothelial cells (HUVECs). LPC increased intracellular calcium ([Ca2+]i) by releasing Ca2+ from intracellular stores and via Ca2+ influx through store-operated channels (SOCs). LPC also increased the generation of reactive oxygen species (ROS) and decreased cell viability. The mRNA expression of Transient receptor potential canonical (TRPC) channel 1 was increased significantly by LPC treatment and suppressed by CGA. CGA inhibited LPC-induced Ca2+ influx and ROS generation, and restored cell viability. These results suggested that CGA inhibits SOC-mediated Ca2+ influx and ROS generation by attenuating TRPC1 expression in LPC-treated HUVECs. Therefore, CGA might protect endothelial cells against LPC injury, thereby inhibiting atherosclerosis. PMID:28088946

  17. [Preventive and remineralization effect over incipient lesions of caries decay by phosphopeptide-amorphous calcium phosphate].

    PubMed

    Juárez-López, María Lilia Adriana; Hernández-Palacios, Rosa Diana; Hernández-Guerrero, Juan Carlos; Jiménez-Farfán, Dolores; Molina-Frechero, Nelly

    2014-01-01

    INTRODUCTION. Dental caries continues to affect a large percentage of Mexican children and currently advises that if diagnosed at an early stage can be reversed with minimally invasive treatments. The casein phosphopeptide amorphous calcium phosphate known as CPP-ACP is a phosphoprotein capable of releasing calcium and phosphate ions in the oral environment promoting remineralization. OBJECTIVE. To evaluate the effect of CPP-ACP with fluoride added in a scholar preventive program. MATERIAL AND METHODS. A cuasi- experimental study was conducted in 104 schools of six years old. The children were classified into three groups and received six months biweekly applications of different treatments: casein phosphopeptide amorphous calcium phosphate added fluoride (CPP-ACPF), sodium fluoride (NaF) and a control group. Clinical evaluation was performed with the laser fluorescence technique (Diagnodent model 2095). 1340 teeth were included: 294 teeth with incipient lesions and 1,046 healthy teeth. Statistical tests of χ2 y Mc Nemar were used. RESULTS. In the group that received the application of CPP-ACPF, 38% of incipient carious lesions were remineralizing compared with 21% in the group receiving the NaF (p < 0.001) and 15% in the control group (p < 0.0001) The percentage of teeth free of caries were preserved in the therapy group phosphoprotein was the biggest. This group also showed the lower proportion of deep carious lesion development (p < 0.0001). CONCLUSION. The application biweekly for six months of CPP-ACPF showed a protective and remineralizing effect on incipient carious lesions. His action was better than the application of NaF. However, to reduce the impact from dental caries in schoolchildren is important to have a comprehensive preventive approach that includes promoting self-care, as well as the application of sealants.

  18. Acidosis and Urinary Calcium Excretion: Insights from Genetic Disorders

    PubMed Central

    Cordat, Emmanuelle; Chambrey, Régine; Dimke, Henrik; Eladari, Dominique

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibition of calcium transport processes within the renal tubule. The mechanisms whereby acid alters the integrity and stability of bone have been examined extensively in the published literature. Here, after briefly reviewing this literature, we consider the effects of acid on calcium transport in the renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis. PMID:27468975

  19. [Effect of calcium cations on acid-base properties and free radical oxidation of dopamine and pyrocatechol].

    PubMed

    Lebedev, A V; Ivanova, M V; Timoshin, A A; Ruuge, E K

    2008-01-01

    Ca2+-induced increase in the rate of pyrocatechol and dopamine oxidation by dioxygen and Ca2+-dependent acid-base properties of the catechols were studied by potentiometric titration, UV/Vis-spectrophotometry, EPR-spectroscopy, and by measurement of oxygen consumption. The effect of Ca2+ on the chain reactions of oxidation can be explained by additional deprotonation (decrease in pKai) of the catechols that accelerates one electron transport to dioxygen and formation of calcium semiquinonate, undergoing further oxidation. The described Ca2+-dependent redox-conversion of ortho-phenols proposes that an additional function of calcium in the cell can be its involvement in free radical oxidoreductive reactions at pH > pKai.

  20. Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures in Community-Dwelling Adults: Evidence Report and Systematic Review for the US Preventive Services Task Force.

    PubMed

    Kahwati, Leila C; Weber, Rachel Palmieri; Pan, Huiling; Gourlay, Margaret; LeBlanc, Erin; Coker-Schwimmer, Manny; Viswanathan, Meera

    2018-04-17

    Osteoporotic fractures result in significant morbidity and mortality. To update the evidence for benefits and harms of vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling adults to inform the US Preventive Services Task Force. PubMed, EMBASE, Cochrane Library, and trial registries through March 21, 2017; references; and experts. Surveillance continued through February 28, 2018. English-language randomized clinical trials (RCTs) or observational studies of supplementation with vitamin D, calcium, or both among adult populations; studies of populations that were institutionalized or had known vitamin D deficiency, osteoporosis, or prior fracture were excluded. Dual, independent review of titles/abstracts and full-text articles and study quality rating using predefined criteria. Random-effects meta-analysis used when at least 3 similar studies were available. Incident fracture, mortality, kidney stones, cardiovascular events, and cancer. Eleven RCTs (N = 51 419) in adults 50 years and older conducted over 2 to 7 years were included. Compared with placebo, supplementation with vitamin D decreased total fracture incidence (1 RCT [n = 2686]; absolute risk difference [ARD], -2.26% [95% CI, -4.53% to 0.00%]) but had no significant association with hip fracture (3 RCTs [n = 5496]; pooled ARD, -0.01% [95% CI, -0.80% to 0.78%]). Supplementation using vitamin D with calcium had no effect on total fracture incidence (1 RCT [n = 36 282]; ARD, -0.35% [95% CI, -1.02% to 0.31%]) or hip fracture incidence (2 RCTs [n = 36 727]; ARD from the larger trial, -0.14% [95% CI, -0.34% to 0.07%]). The evidence for calcium alone was limited, with only 2 studies (n = 339 total) and very imprecise results. Supplementation with vitamin D alone or with calcium had no significant effect on all-cause mortality or incident cardiovascular disease; ARDs ranged from -1.93% to 1.79%, with CIs consistent with no

  1. Omega-3 fatty acids for breast cancer prevention and survivorship.

    PubMed

    Fabian, Carol J; Kimler, Bruce F; Hursting, Stephen D

    2015-05-04

    Women with evidence of high intake ratios of the marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) relative to the omega-6 arachidonic acid have been found to have a reduced risk of breast cancer compared with those with low ratios in some but not all case-control and cohort studies. If increasing EPA and DHA relative to arachidonic acid is effective in reducing breast cancer risk, likely mechanisms include reduction in proinflammatory lipid derivatives, inhibition of nuclear factor-κB-induced cytokine production, and decreased growth factor receptor signaling as a result of alteration in membrane lipid rafts. Primary prevention trials with either risk biomarkers or cancer incidence as endpoints are underway but final results of these trials are currently unavailable. EPA and DHA supplementation is also being explored in an effort to help prevent or alleviate common problems after a breast cancer diagnosis, including cardiac and cognitive dysfunction and chemotherapy-induced peripheral neuropathy. The insulin-sensitizing and anabolic properties of EPA and DHA also suggest supplementation studies to determine whether these omega-3 fatty acids might reduce chemotherapy-associated loss of muscle mass and weight gain. We will briefly review relevant omega-3 fatty acid metabolism, and early investigations in breast cancer prevention and survivorship.

  2. Microorganisms and calcium oxalate stone disease.

    PubMed

    Goldfarb, David S

    2004-01-01

    Microorganisms may have a role in the pathogenesis and prevention of kidney stones. The subjects of this review include nanobacteria, Oxalobacter formigenes, and lactic acid bacteria. Not reviewed here is the well-described role of infections of the urinary tract with Proteus species and other urease-producing organisms associated with struvite stone formation. Nanobacteria have been proposed to be very small (0.08-0.5 nm), ubiquitous organisms that could play a role in stone formation. The theory is that nanobacteria can nucleate carbonate apatite on their surfaces and thereby provide the nidus for stone formation. However, their existence remains uncertain and many investigators are openly skeptical. Recent investigations suggest that they are artifacts, and not actually living organisms, but their proponents continue to study them. O. formigenes is an obligate anaerobe which may be important in the prevention of stone formation. Its sole substrate for generation of ATP is oxalate. It may thereby metabolize its human host's dietary oxalate and diminish intestinal absorption and subsequent urinary excretion of oxalate. There is evidence that the organism's absence, perhaps sometimes due to courses of antibiotics, may be a cause of hyperoxaluria and stone formation. In early investigations, patients not colonized with the organism can be recolonized. Urinary oxalate can be diminished by accompanying an oxalate-containing meal with the organism. One study demonstrated that a preparation of lactic acid bacteria successfully reduced urinary oxalate excretion in 6 patients with calcium oxalate stones and hyperoxaluria. The mechanism of this effect is uncertain since these bacteria lacked the gene possessed by O. formigenes which codes for that organism's oxalate uptake mechanism. The author is currently completing a small randomized controlled clinical trial with this preparation in calcium stone-forming patients with idiopathic hyperoxaluria. Copyright (c) 2004 S

  3. Antimicrobial activity of gallic acid against thermophilic Campylobacter is strain specific and associated with a loss of calcium ions.

    PubMed

    Sarjit, Amreeta; Wang, Yi; Dykes, Gary A

    2015-04-01

    Gallic acid has been suggested as a potential antimicrobial for the control of Campylobacter but its effectiveness is poorly studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of gallic acid against Campylobacter jejuni (n = 8) and Campylobacter coli (n = 4) strains was determined. Gallic acid inhibited the growth of five C. jejuni strains and three C. coli strains (MIC: 15.63-250 μg mL(-1)). Gallic acid was only bactericidal to two C. coli strains (MBC: 125 and 62.5 μg mL(-1)). The mechanism of the bactericidal effect against these two strains (and selected non-susceptible controls) was investigated by determining decimal reduction times and by monitoring the loss of cellular content and calcium ions, and changes in cell morphology. Gallic acid did not result in a loss of cellular content or morphological changes in the susceptible strains as compared to the controls. Gallic acid resulted in a loss of calcium ions (0.58-1.53 μg mL(-1) and 0.54-1.17 μg mL(-1), respectively, over a 180 min period) from the susceptible strains but not the controls. Gallic acid is unlikely to be an effective antimicrobial against Campylobacter in a practical sense unless further interventions to ensure an effective bactericidal mode of action against all strains are developed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. The role of wall calcium in the extension of cell walls of soybean hypocotyls

    NASA Technical Reports Server (NTRS)

    Virk, S. S.; Cleland, R. E.

    1990-01-01

    Calcium crosslinks are load-bearing bonds in soybean (Glycine max (L.) Merr.) hypocotyl cell walls, but they are not the same load-bearing bonds that are broken during acid-mediated cell elongation. This conclusion is reached by studying the relationship between wall calcium, pH and the facilitated creep of frozen-thawed soybean hypocotyl sections. Supporting data include the following observations: 1) 2-[(2-bis-[carboxymethyl]amino-5-methylphenoxy)methyl]-6-methoxy-8-bis[car boxymethyl]aminoquinoline (Quin 2) and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) caused only limited facilitated creep as compared with acid, despite removal of comparable or larger amounts of wall calcium; 2) the pH-response curves for calcium removal and acid-facilitated creep were different; 3) reversible acid-extension occurred even after removal of almost all wall calcium with Quin 2; and 4) growth of abraded sections did not involve a proportional loss of wall calcium. Removal of wall calcium, however, increased the capacity of the walls to undergo acid-facilitated creep. These data indicate that breakage of calcium crosslinks is not a major mechanism of cell-wall loosening in soybean hypocotyl tissues.

  5. Formation and characterization of calcium orthophosphates in the presence of two different acidic macromolecules

    NASA Astrophysics Data System (ADS)

    Pelin, Irina M.; Maier, Vasilica; Suflet, Dana M.; Popescu, Irina; Darie-Nita, Raluca N.; Aflori, Magdalena; Butnaru, Maria

    2017-10-01

    The synthetic nanocrystalline calcium orthophosphates have a notable bioactivity due to the chemical similarity with biological apatite from calcified tissues. In mineralized tissues, the highly ordered structures come from organized assemblies of biomacromolecules and inorganic nanoparticles. One of the purposes of this work was to study the effect of two types of acidic macromolecules: atelocollagen and phosphorylated curdlan onto calcium orthophosphates formation after 30 days of maturation at 2 ± 2 °C. The resulted samples after a long aging time, either calcium orthophosphates or composites, were first investigated by FT-IR spectroscopy and X-ray diffractometry and the results indicated that precipitated hydroxyapatite with low crystallinity was obtained when the synthesis was performed in the presence of phosphorylated curdlan. The macromolecules influenced the morphology of the particles as shown by scanning and transmission electron microscopy. The presence of macromolecules as demonstrated by thermal investigation also influenced the rheological properties of the samples. The second purpose of the work was to evaluate the cytotoxicity of the samples using the MTT assay, and the results revealed very good cells viability. The preliminary results are encouraging regarding the use of these materials for further tests in order to develop injectable bone substitutes.

  6. Calcium supplementation and cardiovascular risk: A rising concern.

    PubMed

    Tankeu, Aurel T; Ndip Agbor, Valirie; Noubiap, Jean Jacques

    2017-06-01

    Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical companies specialized in the marketing of dietary supplements; with calcium supplementation being their main business axis. This is mostly because of the established role of calcium in the prevention and treatment of osteoporosis and, to a lesser extent, its role in the prevention of fractures. Recently, a rising body of evidence on the adverse effect of calcium supplementation on nonskeletal, especially cardiovascular, health has been a cause for concern. In fact, a significant number of studies have reported an association between calcium supplementation and adverse cardiovascular events, even though high dietary calcium intake was shown to have a protective effect. The mechanism by which calcium supplementation could cause a cardiovascular event was still unclear until a recent study published in the Journal of the American Heart Association. Combining this recent finding with available data associating calcium supplementation with cardiovascular mortality and all-cause mortality, we call on the need for an evidence-based approach to calcium supplementation, while stressing on the safety of dietary calcium intake over the former on cardiovascular health. ©2017 Wiley Periodicals, Inc.

  7. Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension

    NASA Technical Reports Server (NTRS)

    Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

  8. Multitrophic effects of calcium availability on invasive alien plants, birds, and bird prey items

    Treesearch

    Vince D' Amico; Greg Shriver; Jake Bowman; Meg Ballard; Whitney Wiest; Liz Tymkiw; Melissa Miller

    2011-01-01

    Acid rain alters forest soil calcium concentrations in two ways: (1) hydrogen ions displace exchangeable calcium adsorbed to soil surfaces, and (2) aluminum is released to soil water by acid rain and displaces adsorbed calcium. This increases the absorption of aluminum by plant roots, and decreases the absorption of calcium, causing calcium to be more readily leached...

  9. Enhanced degradation of trichloroethene by calcium peroxide activated with Fe(III) in the presence of citric acid

    PubMed Central

    ZHANG, Xiang; GU, Xiaogang; LU, Shuguang; MIAO, Zhouwei; XU, Minhui; FU, Xiaori; DANISH, Muhammad; Brusseau, Mark L.; QIU, Zhaofu; SUI, Qian

    2017-01-01

    Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO• and O2−• in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly o direct oxidation by HO•, while O2−• strengthened the generation of HO• by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl−, HCO3−, and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl− production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater. PMID:28959499

  10. Desalted Duck Egg White Peptides Promote Calcium Uptake and Modulate Bone Formation in the Retinoic Acid-Induced Bone Loss Rat and Caco-2 Cell Model.

    PubMed

    Hou, Tao; Liu, Yanshuang; Kolba, Nikolai; Guo, Danjun; He, Hui

    2017-05-12

    Desalted duck egg white peptides (DPs) have been proven to promote calcium uptake in Caco-2 cells and rats treated with a calcium-deficient diet. The retinoic acid-induced bone loss model was used to evaluate the effect of DPs on calcium absorption and bone formation. Three-month-old Wistar female rats were treated with 0.9% saline, DPs (800 mg/kg), or alendronate (5 mg/kg) for three weeks immediately after retinoic acid treatment (80 mg/kg) once daily for two weeks. The model group was significantly higher in serum bone alkaline phosphatase than the other three groups ( p < 0.05), but lower in calcium absorption rate, serum osteocalcin, bone weight index, bone calcium content, bone mineral density, and bone max load. After treatment with DPs or alendronate, the absorption rate increased and some serum and bone indices recovered. The morphology results indicated bone tissue form were ameliorated and numbers of osteoclasts decreased after supplementation with DPs or alendronate. The in vitro study showed that the transient receptor potential vanilloid 6 (TRPV6) calcium channel was the main transport pathway of both DPs and Val-Ser-Glu-Glu peptitde (VSEE), which was identified from DPs. Our results indicated that DPs could be a promising alternative to current therapeutic agents for bone loss because of the promotion of calcium uptake and regulation of bone formation.

  11. Zoledronic Acid for the Treatment and Prevention of Primary and Secondary Osteoporosis

    PubMed Central

    Rizzoli, René

    2010-01-01

    There is increasing interest in therapies that can be administered less frequently and/or avoid gastrointestinal irritation. The efficacy of once-yearly zoledronic acid (5 mg) in the treatment and prevention of osteoporosis has been evaluated in different patient populations. In the 3-year HORIZON-Pivotal Fracture Trial in postmenopausal women with osteoporosis, zoledronic acid reduced the risk of vertebral and hip fracture by 70% and 41%, respectively, versus placebo. The efficacy of zoledronic acid in preventing subsequent fracture in patients with a hip fracture was evaluated in the HORIZON-Recurrent Fracture Trial. New vertebral and nonvertebral fractures were significantly reduced by treatment initiated within 90 days of incident hip fracture, without evidence of delayed fracture healing. Data from a 1-year study show that a single zoledronic acid 5-mg infusion is superior to oral risedronate 5 mg/day for treatment and prevention of glucocorticoid-induced osteoporosis. Increases in bone mineral density and decreases in bone turnover markers were significantly greater with zoledronic acid than with risedronate. Two different treatment regimens of zoledronic acid were found to be more effective than placebo for prevention of bone loss in postmenopausal women and reducing markers of bone turnover after 2 years. In conclusion, zoledronic acid 5 mg once-yearly infusion has demonstrated marked efficacy in the treatment and prevention of primary and secondary osteoporosis, with a combination of fracture risk reduction and prevention of bone loss at key sites. It is the only agent shown to reduce the incidence of fracture and mortality in patients with a previous low-trauma hip fracture. PMID:22870433

  12. Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight US soils

    USDA-ARS?s Scientific Manuscript database

    Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is a common tool to study the structure of soil humic fractions; however, knowledge regarding carbon structural relationships in humic fractions is limited. In this study, mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) fr...

  13. Surface acidity and solid-state compatibility of excipients with an acid-sensitive API: case study of atorvastatin calcium.

    PubMed

    Govindarajan, Ramprakash; Landis, Margaret; Hancock, Bruno; Gatlin, Larry A; Suryanarayanan, Raj; Shalaev, Evgenyi Y

    2015-04-01

    The objectives of this study were to measure the apparent surface acidity of common excipients and to correlate the acidity with the chemical stability of an acid-sensitive active pharmaceutical ingredient (API) in binary API-excipient powder mixtures. The acidity of 26 solid excipients was determined by two methods, (i) by measuring the pH of their suspensions or solutions and (ii) the pH equivalent (pHeq) measured via ionization of probe molecules deposited on the surface of the excipients. The chemical stability of an API, atorvastatin calcium (AC), in mixtures with the excipients was evaluated by monitoring the appearance of an acid-induced degradant, atorvastatin lactone, under accelerated storage conditions. The extent of lactone formation in AC-excipient mixtures was presented as a function of either solution/suspension pH or pHeq. No lactone formation was observed in mixtures with excipients having pHeq > 6, while the lactone levels were pronounced (> 0.6% after 6 weeks at 50°C/20% RH) with excipients exhibiting pHeq < 3. The three pHeq regions (> 6, 3-6, and < 3) were consistent with the reported solution pH-stability profile of AC. In contrast to the pHeq scale, lactone formation did not show any clear trend when plotted as a function of the suspension/solution pH. Two mechanisms to explain the discrepancy between the suspension/solution pH and the chemical stability data were discussed. Acidic excipients, which are expected to be incompatible with an acid-sensitive API, were identified based on pHeq measurements. The incompatibility prediction was confirmed in the chemical stability tests using AC as an example of an acid-sensitive API.

  14. Effects of chlorogenic acid on intracellular calcium regulation in lysophosphatidylcholine-treated endothelial cells.

    PubMed

    Jung, Hye-Jin; Im, Seung-Soon; Song, Dae-Kyu; Bae, Jae-Hoon

    2017-06-01

    Lysophosphatidylcholine (LPC) is a major phospholipid component of oxidized low-density lipoprotein (ox-LDL) and is implicated in its atherogenic activity. This study investigated the effects of LPC on cell viability, intracellular calcium homeostasis, and the protective mechanisms of chlorogenic acid (CGA) in human umbilical vein endothelial cells (HUVECs). LPC increased intracellular calcium ([Ca 2+ ] i ) by releasing Ca 2+ from intracellular stores and via Ca 2+ influx through store-operated channels (SOCs). LPC also increased the generation of reactive oxygen species (ROS) and decreased cell viability. The mRNA expression of Transient receptor potential canonical (TRPC) channel 1 was increased significantly by LPC treatment and suppressed by CGA. CGA inhibited LPC-induced Ca 2+ influx and ROS generation, and restored cell viability. These results suggested that CGA inhibits SOC-mediated Ca 2+ influx and ROS generation by attenuating TRPC1 expression in LPC-treated HUVECs. Therefore, CGA might protect endothelial cells against LPC injury, thereby inhibiting atherosclerosis. [BMB Reports 2017; 50(6): 323-328].

  15. Role of Postoperative Vitamin D and/or Calcium Routine Supplementation in Preventing Hypocalcemia After Thyroidectomy: A Systematic Review and Meta-Analysis

    PubMed Central

    Alhefdhi, Amal; Mazeh, Haggi

    2013-01-01

    Background. Transient hypocalcemia is a frequent complication after total thyroidectomy. Routine postoperative administration of vitamin D and calcium can reduce the incidence of symptomatic postoperative hypocalcemia. We performed a systematic review to assess the effectiveness of this intervention. The primary aim was to evaluate the efficacy of routine postoperative oral calcium and vitamin D supplementation in preventing symptomatic post-thyroidectomy hypocalcemia. The second aim was to draw clear guidelines regarding prophylactic calcium and/or vitamin D therapy for patients after thyroidectomy. Methods. We identified randomized controlled trials comparing the administration of vitamin D or its metabolites to calcium or no treatment in adult patients after thyroidectomy. The search was performed in PubMed, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Google Scholar, and Web of Knowledge databases. Patients with a history of previous neck surgery, calcium supplementation, or renal impairment were excluded. Results. Nine studies with 2,285 patients were included: 22 in the vitamin D group, 580 in the calcium group, 792 in the vitamin D and calcium group, and 891 in the no intervention group, with symptomatic hypocalcemia incidences of 4.6%, 14%, 14%, and 20.5%, respectively. Subcomparisons demonstrated that the incidences of postoperative hypocalcemia were 10.1% versus 18.8% for calcium versus no intervention and 6.8% versus 25.9% for vitamin D and calcium versus no intervention. The studies showed a significant range of variability in patients' characteristics. Conclusions. A significant decrease in postoperative hypocalcemia was identified in patients who received routine supplementation of oral calcium or vitamin D. The incidence decreased even more with the combined administration of both supplements. Based on this analysis, we recommend oral calcium for all patients following thyroidectomy, with the addition of vitamin D for

  16. Calcium alloy as active material in secondary electrochemical cell

    DOEpatents

    Roche, Michael F.; Preto, Sandra K.; Martin, Allan E.

    1976-01-01

    Calcium alloys such as calcium-aluminum and calcium-silicon, are employed as active material within a rechargeable negative electrode of an electrochemical cell. Such cells can use a molten salt electrolyte including calcium ions and a positive electrode having sulfur, sulfides, or oxides as active material. The calcium alloy is selected to prevent formation of molten calcium alloys resulting from reaction with the selected molten electrolytic salt at the cell operating temperatures.

  17. Calcium Overload Accelerates Phosphate-Induced Vascular Calcification Via Pit-1, but not the Calcium-Sensing Receptor.

    PubMed

    Masumoto, Asuka; Sonou, Tomohiro; Ohya, Masaki; Yashiro, Mitsuru; Nakashima, Yuri; Okuda, Kouji; Iwashita, Yuko; Mima, Toru; Negi, Shigeo; Shigematsu, Takashi

    2017-07-01

    Vascular calcification (VC) is a risk factor of cardiovascular and all-cause mortality in patients with chronic kidney disease (CKD). CKD-mineral and bone metabolism disorder is an important problem in patients with renal failure. Abnormal levels of serum phosphate and calcium affect CKD-mineral and bone metabolism disorder and contribute to bone disease, VC, and cardiovascular disease. Hypercalcemia is a contributing factor in progression of VC in patients with CKD. However, the mechanisms of how calcium promotes intracellular calcification are still unclear. This study aimed to examine the mechanisms underlying calcium-induced calcification in a rat aortic tissue culture model. Aortic segments from 7-week-old male Sprague-Dawley rats were cultured in serum-supplemented medium for 10 days. We added high calcium (HiCa; calcium 3.0 mM) to high phosphate (HPi; phosphate 3.8 mM) medium to accelerate phosphate and calcium-induced VC. We used phosphonoformic acid and the calcimimetic R-568 to determine whether the mechanism of calcification involves Pit-1 or the calcium-sensing receptor. Medial VC was significantly augmented by HPi+HiCa medium compared with HPi alone (300%, p<0.05), and was associated with upregulation of Pit-1 protein. Pit-1 protein concentrations in HPi+HiCa medium were greater than those in HPi medium. Phosphonoformic acid completely negated the augmentation of medial VC induced by HPi+HiCa. R-568 had no additive direct effect on medial VC. These results indicated that exposure to HPi+HiCa accelerates medial VC, and this is mediated through Pit-1, not the calcium-sensing receptor.

  18. Nanouric acid or nanocalcium phosphate as central nidus to induce calcium oxalate stone formation: a high-resolution transmission electron microscopy study on urinary nanocrystallites

    PubMed Central

    Gao, Jie; Xue, Jun-Fa; Xu, Meng; Gui, Bao-Song; Wang, Feng-Xin; Ouyang, Jian-Ming

    2014-01-01

    Purpose This study aimed to accurately analyze the relationship between calcium oxalate (CaOx) stone formation and the components of urinary nanocrystallites. Method High-resolution transmission electron microscopy (HRTEM), selected area electron diffraction, fast Fourier transformation of HRTEM, and energy dispersive X-ray spectroscopy were performed to analyze the components of these nanocrystallites. Results The main components of CaOx stones are calcium oxalate monohydrate and a small amount of dehydrate, while those of urinary nanocrystallites are calcium oxalate monohydrate, uric acid, and calcium phosphate. The mechanism of formation of CaOx stones was discussed based on the components of urinary nanocrystallites. Conclusion The formation of CaOx stones is closely related both to the properties of urinary nanocrystallites and to the urinary components. The combination of HRTEM, fast Fourier transformation, selected area electron diffraction, and energy dispersive X-ray spectroscopy could be accurately performed to analyze the components of single urinary nanocrystallites. This result provides evidence for nanouric acid and/or nanocalcium phosphate crystallites as the central nidus to induce CaOx stone formation. PMID:25258530

  19. Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

    USGS Publications Warehouse

    Leenheer, Jerry A.; Reddy, Michael M.

    2008-01-01

    Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

  20. The calcium-sensing receptor regulates mammary gland parathyroid hormone–related protein production and calcium transport

    PubMed Central

    VanHouten, Joshua; Dann, Pamela; McGeoch, Grace; Brown, Edward M.; Krapcho, Karen; Neville, Margaret; Wysolmerski, John J.

    2004-01-01

    The transfer of calcium from mother to milk during lactation is poorly understood. In this report, we demonstrate that parathyroid hormone–related protein (PTHrP) production and calcium transport in mammary epithelial cells are regulated by extracellular calcium acting through the calcium-sensing receptor (CaR). The CaR becomes expressed on mammary epithelial cells at the transition from pregnancy to lactation. Increasing concentrations of calcium, neomycin, and a calcimimetic compound suppress PTHrP secretion by mammary epithelial cells in vitro, whereas in vivo, systemic hypocalcemia increases PTHrP production, an effect that can be prevented by treatment with a calcimimetic. Hypocalcemia also reduces overall milk production and calcium content, while increasing milk osmolality and protein concentrations. The changes in milk calcium content, milk osmolality, and milk protein concentration were mitigated by calcimimetic infusions. Finally, in a three-dimensional culture system that recapitulates the lactating alveolus, activation of the basolateral CaR increases transcellular calcium transport independent of its effect on PTHrP. We conclude that the lactating mammary gland can sense calcium and adjusts its secretion of calcium, PTHrP, and perhaps water in response to changes in extracellular calcium concentration. We believe this defines a homeostatic system that helps to match milk production to the availability of calcium. PMID:14966569

  1. Fabrication and characterization of poly(DL-lactic-co-glycolic acid)/zirconia-hybridized amorphous calcium phosphate composites

    PubMed Central

    WHITED, BRYCE M.; GOLDSTEIN, AARON S.; SKRTIC, DRAGO; LOVE, BRIAN J.

    2010-01-01

    Several minerals, such as hydroxyapatite and β-tricalcium phosphate, have been incorporated into bioresorbable polyester bone scaffolds to increase the osteoconductivity both in vitro and in vivo. More soluble forms of calcium phosphate that release calcium and phosphate ions have been postulated as factors that increase osteoblast differentiation and mineralization. Recently, a zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized allowing controlled release of calcium and phosphate ions. When incorporated into bioresorbable scaffolds, Zr-ACP has the potential to induce osteoconductivity. In this study, 80–90% (w/v) porous poly(DL-LActic-co-glycolic acid) (PLGA) scaffolds were formed by thermal phase separation from dioxane while incorporating Zr-ACP. Scanning electron microscopy revealed a highly porous structure with a pore size ranging from a few μm to about 100 μm, smaller than we had hoped for. Zr-ACP particles were evenly dispersed in the composite structure and incorporated into the pore walls. The amorphous structure of the Zr-ACP was maintained during composite fabrication, as found by X-ray diffraction. Composite scaffolds had larger compressive yield strengths and moduli compared to pure polymer scaffolds. These initial efforts demonstrate that PLGA/Zr-ACP composites can be formed in ways that ultimately serve as promising bone scaffolds in tissue engineering. PMID:16768292

  2. New composite materials prepared by calcium phosphate precipitation in chitosan/collagen/hyaluronic acid sponge cross-linked by EDC/NHS.

    PubMed

    Kaczmarek, B; Sionkowska, A; Kozlowska, J; Osyczka, A M

    2018-02-01

    Nowadays, fabrication of composite materials based on biopolymers is a rising field due to potential for bone repair and tissue engineering application. Blending of different biopolymers and incorporation of inorganic particles in the blend can lead to new materials with improved physicochemical properties and biocompatibility. In this work 3D porous structures called scaffolds based on chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Scaffolds were cross-linked by EDC/NHS. Infrared spectra for the materials were made, the percentage of swelling, scaffolds porosity and density, mechanical parameters, thermal stability were studied. Moreover, the scaffolds were used as matrixes for the calcium phosphate in situ precipitation. SEM images were taken and EDX analysis was carried out for calcium and phosphorous content determination in the scaffold. In addition, the adhesion and proliferation of human osteosarcoma SaOS-2 cells was examined on obtained scaffolds. The results showed that the properties of 3D composites cross-linked by EDC/NHS were altered after the addition of 1, 2 and 5% hyaluronic acid. Mechanical parameters, thermal stability and porosity of scaffolds were improved. Moreover, calcium and phosphorous were found in each kind of scaffold. SEM images showed that the precipitation was homogeneously carried in the whole volume of samples. Attachment of SaOS-2 cells to all modified materials was better compared to unmodified control and proliferation of these cells was markedly increased on scaffolds with precipitated calcium phosphate. Obtained materials can provide the support useful in tissue engineering and regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Iron Mediates N-Methyl-d-aspartate Receptor-dependent Stimulation of Calcium-induced Pathways and Hippocampal Synaptic Plasticity*

    PubMed Central

    Muñoz, Pablo; Humeres, Alexis; Elgueta, Claudio; Kirkwood, Alfredo; Hidalgo, Cecilia; Núñez, Marco T.

    2011-01-01

    Iron deficiency hinders hippocampus-dependent learning processes and impairs cognitive performance, but current knowledge on the molecular mechanisms underlying the unique role of iron in neuronal function is sparse. Here, we investigated the participation of iron on calcium signal generation and ERK1/2 stimulation induced by the glutamate agonist N-methyl-d-aspartate (NMDA), and the effects of iron addition/chelation on hippocampal basal synaptic transmission and long-term potentiation (LTP). Addition of NMDA to primary hippocampal cultures elicited persistent calcium signals that required functional NMDA receptors and were independent of calcium influx through L-type calcium channels or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors; NMDA also promoted ERK1/2 phosphorylation and nuclear translocation. Iron chelation with desferrioxamine or inhibition of ryanodine receptor (RyR)-mediated calcium release with ryanodine-reduced calcium signal duration and prevented NMDA-induced ERK1/2 activation. Iron addition to hippocampal neurons readily increased the intracellular labile iron pool and stimulated reactive oxygen species production; the antioxidant N-acetylcysteine or the hydroxyl radical trapper MCI-186 prevented these responses. Iron addition to primary hippocampal cultures kept in calcium-free medium elicited calcium signals and stimulated ERK1/2 phosphorylation; RyR inhibition abolished these effects. Iron chelation decreased basal synaptic transmission in hippocampal slices, inhibited iron-induced synaptic stimulation, and impaired sustained LTP in hippocampal CA1 neurons induced by strong stimulation. In contrast, iron addition facilitated sustained LTP induction after suboptimal tetanic stimulation. Together, these results suggest that hippocampal neurons require iron to generate RyR-mediated calcium signals after NMDA receptor stimulation, which in turn promotes ERK1/2 activation, an essential step of sustained LTP. PMID:21296883

  4. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease

    PubMed Central

    Hill, Kathleen M.; Martin, Berdine R.; Wastney, Meryl; McCabe, George P.; Moe, Sharon M.; Weaver, Connie M.; Peacock, Munro

    2014-01-01

    Chronic kidney disease (CKD) patients are given calcium carbonate to bind dietary phosphorus and reduce phosphorus retention, and to prevent negative calcium balance. Data are limited on calcium and phosphorus balance in CKD to support this. The aim of this study was to determine calcium and phosphorus balance and calcium kinetics with and without calcium carbonate in CKD patients. Eight stage 3/4 CKD patients, eGFR 36 mL/min, participated in two 3-week balances in a randomized placebo-controlled cross-over study of calcium carbonate (1500 mg/d calcium). Calcium and phosphorus balance were determined on a controlled diet. Oral and intravenous 45calcium with blood sampling and urine and fecal collections were used for calcium kinetics. Fasting blood and urine were collected at baseline and end of each week of each balance period for biochemical analyses. Results showed that patients were in neutral calcium and phosphorus balance while on placebo. Calcium carbonate produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance suggesting tissue deposition. Fasting biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. If they can be extrapolated to effects of chronic therapy, these data caution against the use of calcium carbonate as a phosphate binder. PMID:23254903

  5. Nanosized amorphous calcium carbonate stabilized by poly(ethylene oxide)-b-poly(acrylic acid) block copolymers.

    PubMed

    Guillemet, Baptiste; Faatz, Michael; Gröhn, Franziska; Wegner, Gerhard; Gnanou, Yves

    2006-02-14

    Particles of amorphous calcium carbonate (ACC), formed in situ from calcium chloride by the slow release of carbon dioxide by alkaline hydrolysis of dimethyl carbonate in water, are stabilized against coalescence in the presence of very small amounts of double hydrophilic block copolymers (DHBCs) composed of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) blocks. Under optimized conditions, spherical particles of ACC with diameters less than 100 nm and narrow size distribution are obtained at a concentration of only 3 ppm of PEO-b-PAA as additive. Equivalent triblock or star DHBCs are compared to diblock copolymers. The results are interpreted assuming an interaction of the PAA blocks with the surface of the liquid droplets of the concentrated CaCO3 phase, formed by phase separation from the initially homogeneous reaction mixture. The adsorption layer of the block copolymer protects the liquid precursor of ACC from coalescence and/or coagulation.

  6. Resveratrol Interferes with Fura-2 Intracellular Calcium Measurements.

    PubMed

    Kopp, Richard F; Leech, Colin A; Roe, Michael W

    2014-03-01

    Resveratrol, a naturally occurring polyphenol found in some fruits and especially in grapes, has been reported to provide diverse health benefits. Resveratrol's mechanism of action is the subject of many investigations, and some studies using the ratiometric calcium indicator Fura-2 suggest that it modulates cellular calcium responses. In the current study, contradictory cellular calcium responses to resveratrol applied at concentrations exceeding 10 μM were observed during in vitro imaging studies depending on the calcium indicator used, with Fura-2 indicating an increase in intracellular calcium while Fluo-4 and the calcium biosensor YC3.60 indicated no response. When cells loaded with Fura-2 were treated with 100 μM resveratrol, excitation at 340 nm resulted in a large intensity increase at 510 nm, but the expected concurrent decline with 380 nm excitation was not observed. Pre-treatment of cells with the calcium chelator BAPTA-AM did not prevent a rise in the 340/380 ratio when resveratrol was present, but it did prevent an increase in 340/380 when ATP was applied, suggesting that the resveratrol response was an artifact. Cautious data interpretation is recommended from imaging experiments using Fura-2 concurrently with resveratrol in calcium imaging experiments.

  7. Neurotransmitter Release Can Be Stabilized by a Mechanism That Prevents Voltage Changes Near the End of Action Potentials from Affecting Calcium Currents

    PubMed Central

    Clarke, Stephen G.; Scarnati, Matthew S.

    2016-01-01

    At chemical synapses, presynaptic action potentials (APs) activate voltage-gated calcium channels, allowing calcium to enter and trigger neurotransmitter release. The duration, peak amplitude, and shape of the AP falling phase alter calcium entry, which can affect neurotransmitter release significantly. In many neurons, APs do not immediately return to the resting potential, but instead exhibit a period of depolarization or hyperpolarization referred to as an afterpotential. We hypothesized that presynaptic afterpotentials should alter neurotransmitter release by affecting the electrical driving force for calcium entry and calcium channel gating. In support of this, presynaptic calcium entry is affected by afterpotentials after standard instant voltage jumps. Here, we used the mouse calyx of Held synapse, which allows simultaneous presynaptic and postsynaptic patch-clamp recording, to show that the postsynaptic response is affected significantly by presynaptic afterpotentials after voltage jumps. We therefore tested the effects of presynaptic afterpotentials using simultaneous presynaptic and postsynaptic recordings and AP waveforms or real APs. Surprisingly, presynaptic afterpotentials after AP stimuli did not alter calcium channel responses or neurotransmitter release appreciably. We show that the AP repolarization time course causes afterpotential-induced changes in calcium driving force and changes in calcium channel gating to effectively cancel each other out. This mechanism, in which electrical driving force is balanced by channel gating, prevents changes in calcium influx from occurring at the end of the AP and therefore acts to stabilize synaptic transmission. In addition, this mechanism can act to stabilize neurotransmitter release when the presynaptic resting potential changes. SIGNIFICANCE STATEMENT The shape of presynaptic action potentials (APs), particularly the falling phase, affects calcium entry and small changes in calcium influx can produce large

  8. Effects of soaking and acidification on physicochemical properties of calcium-fortified rice.

    PubMed

    Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa

    2016-06-01

    Calcium-fortified rice was prepared by soaking milled rice in calcium lactate solution, steaming and drying, and physicochemical properties were determined to evaluate effects of calcium concentration (0, 30, 50 g L(-1) ), soaking temperature (ambient temperature, 40 °C, 60 °C) and acidification. Calcium-fortified rice had less lightness. More total solid loss was observed, especially at high soaking temperature. Harder texture was detected with increased calcium concentration. Calcium fortification lowered pasting viscosity of milled rice. Panelists accepted all fortified rice; however, only rice soaked at 50 g L(-1) concentration could be claimed as a good source of calcium. Increasing of soaking temperature induced more penetration of calcium to rice kernels but calcium was lost more easily after washing. With addition of acetic acid to the soaking solution, enriched calcium content was comparable to that of high soaking temperature but with better retention after washing and calcium solubility was improved. Acid induced reduction of lightness and cooked rice hardness but increased total solid loss and pasting viscosity. Although the taste of acetic acid remained, panelists still accepted the fortified rice. Calcium-fortified rice (190.47-194.3 mg 100 g(-1) ) could be successfully produced by soaking milled rice in 50 g L(-1) calcium lactate solution at 40 °C or at ambient temperature with acidification. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  9. Induction of defence gene expression by oligogalacturonic acid requires increases in both cytosolic calcium and hydrogen peroxide in Arabidopsis thaliana.

    PubMed

    Hu, Xiang Yang; Neill, Steven J; Cai, Wei Ming; Tang, Zhang Cheng

    2004-06-01

    Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 ug Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 ug Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS, GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression.

  10. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3-4 chronic kidney disease.

    PubMed

    Hill, Kathleen M; Martin, Berdine R; Wastney, Meryl E; McCabe, George P; Moe, Sharon M; Weaver, Connie M; Peacock, Munro

    2013-05-01

    Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36 ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500 mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week. Calcium kinetics were determined using oral and intravenous (45)calcium. Patients were found to be in neutral calcium and phosphorus balance while on the placebo. Calcium carbonate supplementation produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance, suggesting soft-tissue deposition. Fasting blood and urine biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. Thus, the positive calcium balance produced by calcium carbonate treatment within 3 weeks cautions against its use as a phosphate binder in patients with stage 3 or 4 CKD, if these findings can be extrapolated to long-term therapy.

  11. Preventive effects of the aqueous extract of Cichorium intybus L. flower on ethylene glycol-induced renal calculi in rats

    PubMed Central

    Emamiyan, Mahdieh Zaman; Vaezi, Gholamhassan; Tehranipour, Maryam; Shahrohkabadi, Khdije; Shiravi, Abdolhossein

    2018-01-01

    Objective: Urolithiasis remains a global problem. Despite the availability of numerous methods, no definite therapeutic agent has been yet introduced for the prevention or treatment of kidney stones. In this study, we evaluated the possible preventive effects of aqueous extract of Cichorium intybus L. (chicory) flowers on ethylene glycol-induced renal calculi in rats. Materials and Methods: A total of 24 Wistar rats were randomly divided into four groups and were treated for 30 days. Group A received drinking tap water, while groups B, C, and D were administered with 1% ethylene glycol for induction of calcium oxalate stone formation. Rats in groups C and D received intraperitoneal injections of the aqueous extract of chicory flowers (50 and 200 mg/kg, respectively) since the first day of the experiment. The urine volume, urine pH, and urinary levels of oxalate, citrate, calcium, uric acid, and creatinine as well as serum levels of calcium, uric acid, and creatinine were measured. After 30 days, the rats' kidneys were removed and prepared for histological evaluation of calcium oxalate deposits. One-way analysis of variance (ANOVA), followed by Tukey's test, was performed, using SPSS version 20. Results: The number of calcium oxalate crystals was significantly higher in group B (ethylene glycol-only treated animals), compared to group A (control), group C (50 mg/kg of aqueous extract), and group D (200 mg/kg of aqueous extract) (p<0.05). On day 30, the urine level of citrate, oxalate (p>0.05), and creatinine (p<0.05), as well as urine pH (p<0.05) decreased in groups C and D, compared to group B. Also, urine calcium level, urine uric acid (p>0.05), and urine volume (p<0.05) were higher in group D, compared to group B. In addition, the serum level of calcium, creatinine (p<0.05), and uric acid (p<0.001) decreased in groups C and D. Conclusion: The aqueous extract of chicory flower (50 mg/kg) could reduce the number of calcium oxalate deposits in the urine and reduce

  12. Ultrasonically assisted extraction of calcium and ash from char

    NASA Astrophysics Data System (ADS)

    Mathumba, E. E.; Mbaya, R. K. K.; Kolesnikov, A.

    2018-03-01

    This study characterized and removed calcium and ash content from char to improve the chemical quality of char as reductant for titanium smelting application. Calcium in char can be classified in two parts: mineral matter and cationic metals associated with organic matrix. Virgin and chemically treated char was characterized by using ISO 1171, wet chemistry methods, ISO 19579, XRF, and B.E.T. methods. In this present work, demineralization of char with mild chemical leachants such as acetic acid, citric acid, gluconic acid and Ethylene Diamine Tetra Acetic acid with three different ultrasonic power input (150 W, 270 W and 300 W) and semi-dual frequency of 40 kHz tank was investigated. Actual power dissipated into the system was calculated from the calorimetric measurement. An optimum set of process parameters are identified and validated. The ultrasound technology was compared with soaking technology to determine the efficiency of ultrasound system for the removal of calcium. The removal of calcium was exponentially higher with ultrasonic treatment than without it. Results revealed that mild chemical reagents do not harm the carbon content of char. It is evident from the results that amongst the leachants used; acetic and citric acid has caused significant removal of mineral phases.

  13. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    PubMed

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Lead in calcium supplements.

    PubMed Central

    Scelfo, G M; Flegal, A R

    2000-01-01

    Intercalibrated measurements of lead in calcium supplements indicate the importance of rigorous analytical techniques to accurately quantify contaminant exposures in complex matrices. Without such techniques, measurements of lead concentrations in calcium supplements may be either erroneously low, by as much as 50%, or below the detection limit needed for new public health criteria. In this study, we determined the lead content of 136 brands of supplements that were purchased in 1996. The calcium in the products was derived from natural sources (bonemeal, dolomite, or oyster shell) or was synthesized and/or refined (chelated and nonchelated calcium). The dried products were acid digested and analyzed for lead by high resolution-inductively coupled plasma-mass spectrometry. The method's limit of quantitation averaged 0.06 microg/g, with a coefficient of variation of 1.7% and a 90-100% lead recovery of a bonemeal standard reference material. Two-thirds of those calcium supplements failed to meet the 1999 California criteria for acceptable lead levels (1.5 microg/daily dose of calcium) in consumer products. The nonchelated synthesized and/or refined calcium products, specifically antacids and infant formulas, had the lowest lead concentrations, ranging from nondetectable to 2.9 microg Pb/g calcium, and had the largest proportion of brands meeting the new criteria (85% of the antacids and 100% of the infant formulas). Images Figure 1 Figure 2 PMID:10753088

  15. Use of topical tranexamic acid or aminocaproic acid to prevent bleeding after major surgical procedures.

    PubMed

    Ipema, Heather J; Tanzi, Maria G

    2012-01-01

    To evaluate the literature describing topical use of tranexamic acid or aminocaproic acid for prevention of postoperative bleeding after major surgical procedures. Literature was retrieved through MEDLINE (1946-September 2011) and International Pharmaceutical Abstracts (1970-September 2011) using the terms tranexamic acid, aminocaproic acid, antifibrinolytic, topical, and surgical. In addition, reference citations from publications identified were reviewed. All identified articles in English were evaluated. Clinical trials, case reports, and meta-analyses describing topical use of tranexamic acid or aminocaproic acid to prevent postoperative bleeding were included. A total of 16 publications in the setting of major surgical procedures were included; the majority of data were for tranexamic acid. For cardiac surgery, 4 trials used solutions containing tranexamic acid (1-2.5 g in 100-250 mL of 0.9% NaCl), and 1 trial assessed a solution containing aminocaproic acid (24 g in 250 mL of 0.9% NaCl). These solutions were poured into the chest cavity before sternotomy closure. For orthopedic procedures, all of the data were for topical irrigation solutions containing tranexamic acid (500 mg-3 g in 50-100 mL of 0.9% NaCl) or for intraarticular injections of tranexamic acid (250 mg to 2 g in 20-50 mL of 0.9% sodium chloride, with or without carbazochrome sodium sulfate). Overall, use of topical tranexamic acid or aminocaproic acid reduced postoperative blood loss; however, few studies reported a significant reduction in the number of packed red blood cell transfusions or units given, intensive care unit stay, or length of hospitalization. Topical application of tranexamic acid and aminocaproic acid to decrease postsurgical bleeding after major surgical procedures is a promising strategy. Further data are needed regarding the safety of this hemostatic approach.

  16. Calcium and vitamin D in post menopausal women.

    PubMed

    Aggarwal, Sameer; Nityanand

    2013-12-01

    Calcium and Vitamin D are widely used therapies for Osteoporosis. Vitamin D is not a vitamin in true sense since it is produced in response to the action of sunlight on skin. Vitamin D has multiple roles in the body, not all of them well-understood. Vitamin D supplementation must be considered a form of hormone replacement therapy. Therefore it raises all the questions about efficacy, dose, and side effects. The Efficacy of use of Calcium and Vitamin D in all post menopausal women in terms of the prevention of fracture is uncertain. The Annual worldwide sales of these supplements have been several billion dollars. The variation of the results from various studies of Calcium and Vitamin D supplementation in elderly women suggest that benefit of calcium plus vitamin D on bone mineral density or the risk of fracture is small and may vary from group to group and baseline Vitamin D status. Women taking supplemental vitamin D and calcium have a statistically increased incidence of renal stones, according to evidence from the Women's Health Initiative. Studies have shown association between calcium use and increased risk for cardiovascular disease. In a recent review of evidence from 6 randomized trials evaluating the use of vitamin D and calcium to prevent fractures in postmenopausal women who are not living in a nursing home or other institution, the United States Preventive Task Force (USPTF) found no evidence of a benefit from supplementation with 400 IU or less of vitamin D3 and 1000 mg or less of calcium. Also in a report from institute of Medicine Committee, there was insufficient evidence, particularly from randomized trials, that vitamin D treatment affected the risk of non skeletal outcomes like risk of cancer, cardiovascular disease, diabetes, infections, autoimmune disease, and other extra skeletal outcomes.

  17. Effects of Hydration and Calcium Supplementation on Urine Calcium Concentration in Healthy Postmenopausal Women.

    PubMed

    Harris, Susan S; Dawson-Hughes, Bess

    2015-01-01

    The aim of this study was to determine whether calcium supplementation, compared with placebo, increases urine calcium concentrations to levels indicative of increased renal stone risk, and the role that fluid intake, as indicated by urine volume, may play in mitigating this risk. This is a secondary analysis of data from a randomized placebo-controlled trial of 500 mg/d calcium supplementation to prevent bone loss. Subjects were 240 white postmenopausal women age 40 to 70 years in good general health. Effects of supplementation on 1-year changes in 24h urine calcium concentration and urine volume were examined. Both treatment group and urine volume were strong independent predictors of urine calcium concentration (p < 0.001). Among subjects with urine volume under 2 L/24 h, more than half of placebo subjects were at lowest risk for renal stones compared with less than 35% of calcium-supplemented subjects. Among those with higher urine volumes, all placebo subjects and more than 80% of calcium supplemented subjects were at lowest risk. The increased risk of renal stones with calcium supplement use may be largely eliminated with adequate fluid intake, but older adults may not spontaneously consume adequate fluids to minimize this risk and should be counseled to do so.

  18. An improved method for emergent decontamination of ocular and dermal hydrofluoric acid splashes.

    PubMed

    Soderberg, Kjell; Kuusinen, Petri; Mathieu, Laurence; Hall, Alan H

    2004-08-01

    Accidental hydrofluoric acid (HF) splashes often occur in industrial settings. HF easily penetrates into tissues by initial acid action allowing fluoride ions to penetrate deeply, chelating calcium and magnesium. Resultant hypocalcemia and hypomagnesemia can be fatal. This report describes the utilization of Hexafluorine--a hypertonic, amphoteric, chelating decontamination solution--in workplaces where water decontamination followed by calcium gluconate inunction failed to prevent HF burns and systemic toxicity. Between 1998 and 1999, 16 cases of ocular and dermal HF splashes with either 70% HF or 6% HF/15% nitric acid (HNO3) were decontaminated with Hexafluorine at the worksite. HF burns did not develop and medical treatment other than initial decontamination was not reQuired in 12/16 (75%). In 7/16 (44%) cases, lost work time corresponded to duration of hospital observation (mean < 1 d).

  19. Growth hormone secretagogues prevent dysregulation of skeletal muscle calcium homeostasis in a rat model of cisplatin‐induced cachexia

    PubMed Central

    Conte, Elena; Camerino, Giulia Maria; Mele, Antonietta; De Bellis, Michela; Pierno, Sabata; Rana, Francesco; Fonzino, Adriano; Caloiero, Roberta; Rizzi, Laura; Bresciani, Elena; Ben Haj Salah, Khoubaib; Fehrentz, Jean‐Alain; Martinez, Jean; Giustino, Arcangela; Mariggiò, Maria Addolorata; Coluccia, Mauro; Tricarico, Domenico; Lograno, Marcello Diego; De Luca, Annamaria; Torsello, Antonio; Conte, Diana

    2017-01-01

    (excitability and resting macroscopic conductance) and in vivo (forelimb force and muscle volume) outcomes in cachectic animals. Administration of hexarelin or JMV2894 markedly reduced the cisplatin‐induced alteration of calcium homeostasis by both common as well as drug‐specific mechanisms of action. This effect correlated with muscle function preservation as well as amelioration of various atrophic indexes, thus supporting the functional impact of GHS activity on calcium homeostasis. Conclusions Our findings provide a direct evidence that a dysregulation of calcium homeostasis plays a key role in cisplatin‐induced model of cachexia gaining insight into the etiopathogenesis of this form of muscle wasting. Furthermore, our demonstration that GHS administration efficaciously prevents cisplatin‐induced calcium homeostasis alteration contributes to elucidate the mechanism of action through which GHS could potentially ameliorate chemotherapy‐associated cachexia. PMID:28294567

  20. Neurotransmitter Release Can Be Stabilized by a Mechanism That Prevents Voltage Changes Near the End of Action Potentials from Affecting Calcium Currents.

    PubMed

    Clarke, Stephen G; Scarnati, Matthew S; Paradiso, Kenneth G

    2016-11-09

    At chemical synapses, presynaptic action potentials (APs) activate voltage-gated calcium channels, allowing calcium to enter and trigger neurotransmitter release. The duration, peak amplitude, and shape of the AP falling phase alter calcium entry, which can affect neurotransmitter release significantly. In many neurons, APs do not immediately return to the resting potential, but instead exhibit a period of depolarization or hyperpolarization referred to as an afterpotential. We hypothesized that presynaptic afterpotentials should alter neurotransmitter release by affecting the electrical driving force for calcium entry and calcium channel gating. In support of this, presynaptic calcium entry is affected by afterpotentials after standard instant voltage jumps. Here, we used the mouse calyx of Held synapse, which allows simultaneous presynaptic and postsynaptic patch-clamp recording, to show that the postsynaptic response is affected significantly by presynaptic afterpotentials after voltage jumps. We therefore tested the effects of presynaptic afterpotentials using simultaneous presynaptic and postsynaptic recordings and AP waveforms or real APs. Surprisingly, presynaptic afterpotentials after AP stimuli did not alter calcium channel responses or neurotransmitter release appreciably. We show that the AP repolarization time course causes afterpotential-induced changes in calcium driving force and changes in calcium channel gating to effectively cancel each other out. This mechanism, in which electrical driving force is balanced by channel gating, prevents changes in calcium influx from occurring at the end of the AP and therefore acts to stabilize synaptic transmission. In addition, this mechanism can act to stabilize neurotransmitter release when the presynaptic resting potential changes. The shape of presynaptic action potentials (APs), particularly the falling phase, affects calcium entry and small changes in calcium influx can produce large changes in

  1. The role of calcium in osteoporosis.

    PubMed

    Arnaud, C D; Sanchez, S D

    1990-01-01

    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25-30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. The RDA for age 10-25 is 1200 mg/day. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years old). Starting at age 40-45, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D3. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Available evidence suggests that the impairments of intestinal calcium absorption observed during the menopause and aging can be overcome only by inordinately large calcium intakes (1500 to 2500 mg/day). Since this amount is difficult to derive from the diet, can cause constipation, and may not prevent trabecular bone loss, it should not be used as a substitute for sex hormone replacement. Women taking estrogen replacement should be provided the RDA for calcium of 800 mg/day at a minimum. Those who cannot or will not take estrogen should be asked to ingest at least 1000 to 1500 mg/day of calcium to delay cortical bone loss and prevent secondary hyperparathyroidism. It should be emphasized that up to 2000 mg/day of calcium is safe in teenaged children and adults. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. It is also possible that excessive intakes of phosphate could have a

  2. Growth hormone secretagogues prevent dysregulation of skeletal muscle calcium homeostasis in a rat model of cisplatin-induced cachexia.

    PubMed

    Conte, Elena; Camerino, Giulia Maria; Mele, Antonietta; De Bellis, Michela; Pierno, Sabata; Rana, Francesco; Fonzino, Adriano; Caloiero, Roberta; Rizzi, Laura; Bresciani, Elena; Ben Haj Salah, Khoubaib; Fehrentz, Jean-Alain; Martinez, Jean; Giustino, Arcangela; Mariggiò, Maria Addolorata; Coluccia, Mauro; Tricarico, Domenico; Lograno, Marcello Diego; De Luca, Annamaria; Torsello, Antonio; Conte, Diana; Liantonio, Antonella

    2017-06-01

    vivo (forelimb force and muscle volume) outcomes in cachectic animals. Administration of hexarelin or JMV2894 markedly reduced the cisplatin-induced alteration of calcium homeostasis by both common as well as drug-specific mechanisms of action. This effect correlated with muscle function preservation as well as amelioration of various atrophic indexes, thus supporting the functional impact of GHS activity on calcium homeostasis. Our findings provide a direct evidence that a dysregulation of calcium homeostasis plays a key role in cisplatin-induced model of cachexia gaining insight into the etiopathogenesis of this form of muscle wasting. Furthermore, our demonstration that GHS administration efficaciously prevents cisplatin-induced calcium homeostasis alteration contributes to elucidate the mechanism of action through which GHS could potentially ameliorate chemotherapy-associated cachexia. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  3. The binding of calcium ions by erythrocytes and `ghost'-cell membranes

    PubMed Central

    Long, C.; Mouat, Barbara

    1971-01-01

    1. Washed human erythrocytes, suspended in iso-osmotic sucrose containing 2.5mm-calcium chloride, bind about 400μg-atoms of calcium/litre of packed cells. Sucrose may be replaced by other sugars. 2. Partial replacement of sucrose by iso-osmotic potassium chloride diminishes the uptake of calcium, 50% inhibition occurring at about 50mm-potassium chloride. 3. Other univalent cations behave like potassium, whereas bivalent cations are much more inhibitory. The tervalent cations, yttrium and lanthanum, however, are the most effective inhibitors of calcium uptake. 4. An approximate correlation exists between the calcium uptake and the sialic acid content of erythrocytes of various species and of human erythrocytes that have been partially depleted of sialic acid by treatment with neuraminidase. However, even after complete removal of sialic acid, human erythrocytes still bind about 140μg-atoms of calcium/litre of packed cells. 5. A Scatchard (1949) plot of calcium uptake at various Ca2+ concentrations in the suspending media shows the presence of three different binding sites on the external surface of the human erythrocyte membrane. 6. Erythrocyte `ghost' cells, the membranes of which appear to be permeable to Ca2+ ions, can bind about 1000μg-atoms of calcium per `ghost'-cell equivalent of 1 litre of packed erythrocytes. This indicates that there are also binding sites for calcium on the internal surface of the erythrocyte membrane. PMID:5124387

  4. The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

    USGS Publications Warehouse

    Kramer, Henry

    1956-01-01

    A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

  5. The calcium paradox - What should we have to fear?

    PubMed Central

    de Oliveira, Marcos Aurélio Barboza; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseni; Cortez, José Luís Lasso; Goissis, Gilberto; Braile, Domingo Marcolino

    2014-01-01

    The calcium paradox was first mentioned in 1966 by Zimmerman et al. Thereafter gained great interest from the scientific community due to the fact of the absence of calcium ions in heart muscle cells produce damage similar to ischemia-reperfusion. Although not all known mechanisms involved in cellular injury in the calcium paradox intercellular connection maintained only by nexus seems to have a key role in cellular fragmentation. The addition of small concentrations of calcium, calcium channel blockers, and hyponatraemia hypothermia are important to prevent any cellular damage during reperfusion solutions with physiological concentration of calcium. PMID:25140476

  6. Lack of Evidence Linking Calcium With or Without Vitamin D Supplementation to Cardiovascular Disease in Generally Healthy Adults: A Clinical Guideline From the National Osteoporosis Foundation and the American Society for Preventive Cardiology.

    PubMed

    Kopecky, Stephen L; Bauer, Douglas C; Gulati, Martha; Nieves, Jeri W; Singer, Andrea J; Toth, Peter P; Underberg, James A; Wallace, Taylor C; Weaver, Connie M

    2016-12-20

    Calcium is the dominant mineral present in bone and a shortfall nutrient in the American diet. Supplements have been recommended for persons who do not consume adequate calcium from their diet as a standard strategy for the prevention of osteoporosis and related fractures. Whether calcium with or without vitamin D supplementation is beneficial or detrimental to vascular health is not known. The National Osteoporosis Foundation and American Society for Preventive Cardiology convened an expert panel to evaluate the effects of dietary and supplemental calcium on cardiovascular disease based on the existing peer-reviewed scientific literature. The panel considered the findings of the accompanying updated evidence report provided by an independent evidence review team at Tufts University. The National Osteoporosis Foundation and American Society for Preventive Cardiology adopt the position that there is moderate-quality evidence (B level) that calcium with or without vitamin D intake from food or supplements has no relationship (beneficial or harmful) to the risk for cardiovascular and cerebrovascular disease, mortality, or all-cause mortality in generally healthy adults at this time. In light of the evidence available to date, calcium intake from food and supplements that does not exceed the tolerable upper level of intake (defined by the National Academy of Medicine as 2000 to 2500 mg/d) should be considered safe from a cardiovascular standpoint.

  7. Prevention and treatment of glucocorticoid-induced osteoporosis: a comparison of calcitriol, vitamin D plus calcium, and alendronate plus calcium.

    PubMed

    Sambrook, Philip N; Kotowicz, Mark; Nash, Peter; Styles, Colin B; Naganathan, Vasi; Henderson-Briffa, Kathy N; Eisman, John A; Nicholson, Geoff C

    2003-05-01

    High-dose corticosteroids, used for many medical conditions, are associated with rapid bone loss from sites such as the vertebrae, and compression fractures can be observed within months. Recent trials suggest treatment with bisphosphonates or active vitamin D analogs can reduce bone loss and the risk of fracture associated with glucocorticoids, but few studies have directly compared such agents. We conducted a randomized, multicenter, open-label trial to compare the efficacy of alendronate, calcitriol, and simple vitamin D in prevention and treatment of glucocorticoid-induced bone loss. A total of 195 subjects (134 females and 61 males) commencing or already taking glucocorticoids were randomized to one of three groups: calcitriol, 0.5 to 0.75 microg/day; simple vitamin D (ergocalciferol, 30,000 IU weekly) plus calcium carbonate (600 mg daily); or alendronate, 10 mg/day plus calcium carbonate (600 mg daily). Over 2 years, mean lumbar bone mineral density change was +5.9% with alendronate, -0.5% with ergocalciferol, and -0.7% with calcitriol (p < 0.001). At the femoral neck, there was no significant difference in bone mineral density change between the treatments over 2 years: alendronate (+0.9%), ergocalciferol (-3.2%), and calcitriol (-2.2%). Lumbar bone loss varied according to whether patients were starting or receiving chronic glucocorticoids, and there was a significant treatment x prior glucocorticoid use interaction effect. Six of 66 calcitriol subjects, 1 of 61 ergocalciferol subjects, and 0 of 64 alendronate subjects sustained new vertebral fractures. These data do not suggest any difference between simple vitamin D and calcitriol but do show that alendronate was superior to either treatment for glucocorticoid induced bone loss.

  8. New uses for calcium chloride solution as a mounting medium.

    PubMed

    Herr, J M

    1992-01-01

    Fresh cross sections of stems (Psilotum nudum, Coleus blumei, and Pelargonium peltatum) and roots (Setcreasea purpurea) 120 microns thick were fixed in FPA50 (formalin: propionic acid: 50% ethanol, 5:5:90, v/v) for 24 hr and stored in 70% ethanol. The sections were transferred to water and then to 1% phloroglucin in 20% calcium chloride solution plus either hydrochloric, nitric, or lactic acid in the following ratios of phloroglucin-CaCl2 solution:acid: 25:4, 20:2, or 15:5. The sections were mounted on slides either in one of the three mixtures or in fresh 20% calcium chloride solution. A rapid reaction of the acid-phloroglucin with lignin produced a deep red color in tracheary elements and an orange-red color in sclerenchyma. Fixed and stored leaf pieces from Nymphaea odorata were autoclaved in lactic acid, washed in two changes of 95% ethanol, transferred to water, and treated with the three acid-phloroglucin-calcium chloride mixtures. The abundant astrosclereids stained an orange-red color similar to that of sclerenchyma in the sections. In addition, a new method is reported for specifically staining lignified tissues. When sections or leaf pieces are stained in aqueous 0.05% toluidine blue O, then placed in 20% calcium chloride solution, all tissues destain except those with lignified or partially lignified cell walls. Thus, toluidine blue O applied as described becomes a reliable specific test for lignin comparable to the acid-phloroglucin test.

  9. Dexmedetomidine Prevents Excessive γ-Aminobutyric Acid Type A Receptor Function after Anesthesia.

    PubMed

    Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Lei, Gang; Mostafa, Fariya; Wang, Junhui; Lecker, Irene; Avramescu, Sinziana; Xie, Yu-Feng; Chan, Nathan K; Fernandez-Escobar, Alejandro; Woo, Junsung; Chan, Darren; Ramsey, Amy J; Sivak, Jeremy M; Lee, C Justin; Bonin, Robert P; Orser, Beverley A

    2018-06-08

    Postoperative delirium is associated with poor long-term outcomes and increased mortality. General anesthetic drugs may contribute to delirium because they increase cell-surface expression and function of α5 subunit-containing γ-aminobutyric acid type A receptors, an effect that persists long after the drugs have been eliminated. Dexmedetomidine, an α2 adrenergic receptor agonist, prevents delirium in patients and reduces cognitive deficits in animals. Thus, it was postulated that dexmedetomidine prevents excessive function of α5 γ-aminobutyric acid type A receptors. Injectable (etomidate) and inhaled (sevoflurane) anesthetic drugs were studied using cultured murine hippocampal neurons, cultured murine and human cortical astrocytes, and ex vivo murine hippocampal slices. γ-Aminobutyric acid type A receptor function and cell-signaling pathways were studied using electrophysiologic and biochemical methods. Memory and problem-solving behaviors were also studied. The etomidate-induced sustained increase in α5 γ-aminobutyric acid type A receptor cell-surface expression was reduced by dexmedetomidine (mean ± SD, etomidate: 146.4 ± 51.6% vs. etomidate + dexmedetomidine: 118.4 ± 39.1% of control, n = 8 each). Dexmedetomidine also reduced the persistent increase in tonic inhibitory current in hippocampal neurons (etomidate: 1.44 ± 0.33 pA/pF, n = 10; etomidate + dexmedetomidine: 1.01 ± 0.45 pA/pF, n = 9). Similarly, dexmedetomidine prevented a sevoflurane-induced increase in the tonic current. Dexmedetomidine stimulated astrocytes to release brain-derived neurotrophic factor, which acted as a paracrine factor to reduce excessive α5 γ-aminobutyric acid type A receptor function in neurons. Finally, dexmedetomidine attenuated memory and problem-solving deficits after anesthesia. Dexmedetomidine prevented excessive α5 γ-aminobutyric acid type A receptor function after anesthesia. This novel α2 adrenergic receptor- and brain-derived neurotrophic factor

  10. Benzodiazepine-induced hippocampal CA1 neuron alpha-amino-3-hydroxy-5-methylisoxasole-4-propionic acid (AMPA) receptor plasticity linked to severity of withdrawal anxiety: differential role of voltage-gated calcium channels and N-methyl-D-aspartic acid receptors.

    PubMed

    Xiang, Kun; Tietz, Elizabeth I

    2007-09-01

    Withdrawal from 1-week oral administration of the benzodiazepine, flurazepam (FZP) is associated with increased alpha-amino-3-hydroxy-5-methylisoxasole-4-propionic acid (AMPA) receptor (AMPAR) miniature excitatory postsynaptic currents (mEPSCs) but reduction of N-methyl-D-aspartic acid (NMDA) receptor (NMDAR)-evoked (e)EPSCs in hippocampal CA1 neurons. A positive correlation was observed between increased AMPAR-mediated mEPSC amplitude and anxiety-like behavior in 1-day FZP-withdrawn rats. These effects were disrupted by systemic AMPAR antagonist administration (GYKI-52466, 0.5 mg/kg, intraperitoneal) at withdrawal onset, strengthening the hypothesis that CA1 neuron AMPAR-mediated hyperexcitability is a central component of a functional anatomic circuit associated with the expression of withdrawal anxiety. Abolition of AMPAR current upregulation in 2-day FZP withdrawn rats by GYKI-52466 injection also reversed the reduction in NMDAR-mediated eEPSC amplitude in CA1 neurons from the same rats, suggesting that downregulation of NMDAR function may serve a protective, negative-feedback role to prevent AMPAR-mediated neuronal overexcitation. NMDAR antagonist administration (MK-801, 0.25 mg/kg intraperitoneally) had no effect on modifying increased glutamatergic strength or on withdrawal anxiety, whereas injection of an L-type voltage-gated calcium channel antagonist, nimodipine (10 mg/kg, intraperitoneally) averted AMPAR current enhancement and anxiety-like behavior, suggesting that these manifestations may be initiated by a voltage-gated calcium channel-dependent signal transduction pathway. An evidence-based model of likely cellular mechanisms in the hippocampus contributing to benzodiazepine withdrawal anxiety was proposed implicating regulation of multiple CA1 neuron ion channels.

  11. Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients.

    PubMed

    Janssen, M J; van der Kuy, A; ter Wee, P M; van Boven, W P

    1996-02-01

    Prevention of secondary hyperparathyroidism in uremia necessitates correction of hyperphosphatemia and hypocalcemia. In order to avoid aluminum toxicity, calcium containing phosphate binders are used increasingly, instead of aluminium hydroxide. Recent studies have shown that calcium acetate has many characteristics of an ideal phosphate binder. It is, for instance, a more readily soluble salt compared with calcium carbonate. This advantage might, however, disappear if calcium carbonate is taken on an empty stomach, a few minutes before meals. We examined the efficacy of three different phosphate binding agents in a randomized prospective study of 53 patients on regular hemodialysis. Bicarbonate dialyses were performed with a dialysate calcium concentration of 1.75 mmol/l. After a three-week wash-out period, patients received either aluminum hydroxide (control group), calcium acetate, or calcium carbonate as their phosphate binder. Patients were instructed to take the calcium salts a few minutes before meals on an empty stomach, and aluminum hydroxide during meals. Serum calcium, phosphate, intact parathormone, and alkaline phosphatase levels were determined every month. Patient compliance was estimated every month by asking the patients which phosphate binder and what daily dose they had used. Aluminum hydroxide tended to be the most effective phosphate binder. The mean +/- SEM required daily dose of calcium acetate at 12 months was 5.04 +/- 0.60 g, corresponding to 10.1 +/- 1.20 tablets of 500 mg. Co-medication with aluminum hydroxide, however, was needed (1.29 +/- 0.54 g per day, corresponding to 2.6 +/- 1.08 tablets of 500 mg). The required daily calcium carbonate dose appeared to be 2.71 +/- 0.48 g, corresponding to 5.4 +/- 0.95 capsules of 500 mg, with an adjuvant daily aluminum hydroxide dose of 0.69 +/- 0.27 g, corresponding to 1.4 +/- 0.55 tablets of 500 mg (p = 0.0055). Thus, the mean daily doses of elemental calcium were comparable between the calcium

  12. Perlinhibin, a Cysteine-, Histidine-, and Arginine-Rich Miniprotein from Abalone (Haliotis laevigata) Nacre, Inhibits In Vitro Calcium Carbonate Crystallization

    PubMed Central

    Mann, Karlheinz; Siedler, Frank; Treccani, Laura; Heinemann, Fabian; Fritz, Monika

    2007-01-01

    We have isolated a 4.785 Da protein from the nacreous layer of the sea snail Haliotis laevigata (greenlip abalone) shell after demineralization with acetic acid. The sequence of 41 amino acids was determined by Edman degradation supported by mass spectrometry. The most abundant amino acids were cysteine (19.5%), histidine (17%), and arginine (14.6%). The positively charged amino acids were almost counterbalanced by negatively charged ones resulting in a calculated isoelectric point of 7.86. Atomic-force microscopy studies of the interaction of the protein with calcite surfaces in supersaturated calcium carbonate solution or calcium chloride solution showed that the protein bound specifically to calcite steps, inhibiting further crystal growth at these sites in carbonate solution and preventing crystal dissolution when carbonate was substituted with chloride. Therefore this protein was named perlinhibin. X-ray diffraction investigation of the crystal after atomic-force microscopy growth experiments showed that the formation of aragonite was induced on the calcite substrate around holes caused by perlinhibin crystal-growth inhibition. The strong interaction of the protein with calcium carbonate was also shown by vapor diffusion crystallization. In the presence of the protein, the crystal surfaces were covered with holes due to protein binding and local inhibition of crystal growth. In addition to perlinhibin, we isolated and sequenced a perlinhibin-related protein, indicating that perlinhibin may be a member of a family of closely related proteins. PMID:17496038

  13. Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis

    PubMed Central

    2013-01-01

    Background Calcium deficiency is a global public-health problem. Although the initial stage of calcium deficiency can lead to metabolic alterations or potential pathological changes, calcium deficiency is difficult to diagnose accurately. Moreover, the details of the molecular mechanism of calcium deficiency remain somewhat elusive. To accurately assess and provide appropriate nutritional intervention, we carried out a global analysis of metabolic alterations in response to calcium deficiency. Methods The metabolic alterations associated with calcium deficiency were first investigated in a rat model, using urinary metabonomics based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis. Correlations between dietary calcium intake and the biomarkers identified from the rat model were further analyzed to confirm the potential application of these biomarkers in humans. Results Urinary metabolic-profiling analysis could preliminarily distinguish between calcium-deficient and non-deficient rats after a 2-week low-calcium diet. We established an integrated metabonomics strategy for identifying reliable biomarkers of calcium deficiency using a time-course analysis of discriminating metabolites in a low-calcium diet experiment, repeating the low-calcium diet experiment and performing a calcium-supplement experiment. In total, 27 biomarkers were identified, including glycine, oxoglutaric acid, pyrophosphoric acid, sebacic acid, pseudouridine, indoxyl sulfate, taurine, and phenylacetylglycine. The integrated urinary metabonomics analysis, which combined biomarkers with regular trends of change (types A, B, and C), could accurately assess calcium-deficient rats at different stages and clarify the dynamic pathophysiological changes and molecular mechanism of calcium deficiency in detail. Significant correlations between calcium intake and two biomarkers, pseudouridine (Pearson

  14. Enhanced drug encapsulation and extended release profiles of calcium-alginate nanoparticles by using tannic acid as a bridging cross-linking agent.

    PubMed

    Abulateefeh, Samer R; Taha, Mutasem O

    2015-01-01

    Calcium alginate nanoparticles (NPs) suffer from sub-optimal stability in bio-relevant media leading to low drug encapsulation efficiency and uncontrolled release profiles. To sort out these drawbacks, a novel approach is proposed herein based on introducing tannic acid into these NPs to act as a bridging cross-linking aid agent. Calcium-alginate NPs were prepared by the ionotropic gelation method and loaded with diltiazem hydrochloride as a model drug. These NPs were characterized in terms of particle size, zeta potential, and morphology, and results were explained in accordance with Fourier-transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The incorporation of tannic acid led to more than four folds increase in drug encapsulation efficiency (i.e. from 15.3% to 69.5%) and reduced burst drug release from 44% to around 10% within the first 30 min. These findings suggest the possibility of improving the properties of Ca-alginate NPs by incorporating cross-linking aid agents under mild conditions.

  15. Removal of toxic metals from leachates from hazardous solid wastes and reduction of toxicity to microtox by the use of calcium alginate beads containing humic acid.

    PubMed

    Pandey, Ashok K; Pandey, Shri Dhar; Misra, Virendra

    2002-06-01

    Improper disposal of hazardous wastes can lead to release of potentially harmful substances through leaching such as heavy metals, which ultimately contaminate soil, sediment surface water, and groundwater through runoff. To remove these toxic metals and avoid any adverse effect on the ecosystem, a novel approach involving calcium alginate (CA) beads containing humic acid (HA) was used. For this, 10% leachates of the waste obtained from two major industrial units with electroplating processess were prepared at neutral pH and analyzed by atomic absorption spectrophotometry (AAS). Both leachates contained Cd, Cu, Cr, Ni, Mn, Fe, and Zn. The concentrations of Ni, Mn, Fe, and Zn in the waste were found to be significant. The leachates analyzed were passed through columns packed with calcium alginate beads with or without humic acid. The concentrations of various metals in beads and in different fractions collected after adsorption were measured. Data recorded indicate that calcium alginate beads containing humic acids are more efficient in removal of all metals in substantial amounts from the two leachates. Along with removal of metals, this process led to considerable detoxification of the leachates as tested by Microtox assay, indicated by earlier protection and higher EC(50). The significance of the results in relation to removal of toxic metals by beads containing humic acid is discussed. (c) 2002 Elsevier Science (USA).

  16. The combined oral contraceptive pill containing drospirenone and ethinyl estradiol plus levomefolate calcium.

    PubMed

    Rapkin, Rachel B; Creinin, Mitchell D

    2011-10-01

    Neural tube defects are the second most common congenital anomaly in the United States, although their incidence may be decreased by periconception folic acid supplementation. A new oral contraceptive containing drospirenone and ethinyl estradiol plus levomefolate calcium was formulated to decrease the risk of neural tube defects in pregnancies conceived while taking or shortly after discontinuing this pill. Because of its novelty, very few studies have been performed to evaluate the efficacy, side effects and safety related to contraception, premenstrual dysphoric disorder and acne; therefore, literature evaluating similar contraceptives without levomefolate is reviewed. Additionally, we review studies evaluating the addition of levomefolate calcium to oral contraceptives containing 3 mg drospirenone and either 20 or 30 μg ethinyl estradiol. To date, no study has been performed to evaluate the effect this new oral contraceptive has on reducing the incidence of neural tube defects. This new pill has similar contraceptive efficacy, side effect, safety and benefits profile to other drospirenone-containing contraceptives. While also approved to prevent neural tube defects, no studies validate this claim and physician time is better spent counseling women, regardless of contraceptive choice, on the importance of folic acid supplementation during the child-bearing years.

  17. Mast cell degranulation and calcium influx are inhibited by an Echinacea purpurea extract and the alkylamide dodeca-2E,4E-dienoic acid isobutylamide.

    PubMed

    Gulledge, Travis V; Collette, Nicholas M; Mackey, Emily; Johnstone, Stephanie E; Moazami, Yasamin; Todd, Daniel A; Moeser, Adam J; Pierce, Joshua G; Cech, Nadja B; Laster, Scott M

    2018-02-15

    Native Americans used plants from the genus Echinacea to treat a variety of different inflammatory conditions including swollen gums, sore throats, skin inflammation, and gastrointestinal disorders. Today, various Echinacea spp. preparations are used primarily to treat upper respiratory infections. The goal of this study was to evaluate the effects of an ethanolic E. purpurea (L) Moench root extract and the alkylamide dodeca-2E,4E-dienoic acid isobutylamide (A15) on mast cells, which are important mediators of allergic and inflammatory responses. Inhibition of mast cell activation may help explain the traditional use of Echinacea. A15 was evaluated for its effects on degranulation, calcium influx, cytokine and lipid mediator production using bone marrow derived mast cells (BMMCs) and the transformed rat basophilic leukemia mast cell line RBL-2H3. Methods included enzymatic assays, fluorimetry, ELISAs, and microscopy. A root extract of E. purpurea, and low and high alkylamide-containing fractions prepared from this extract, were also tested for effects on mast cell function. Finally, we tested A15 for effects on calcium responses in RAW 264.7 macrophage and Jurkat T cell lines. A15 inhibited ß-hexosaminidase release from BMMCs and RBL-2H3 cells after treatment with the calcium ionophore A23187 by 83.5% and 48.4% at 100µM, respectively. Inhibition also occurred following stimulation with IgE anti-DNP/DNP-HSA. In addition, A15 inhibited 47% of histamine release from A23187-treated RBL-2H3 cells. A15 prevented the rapid rise in intracellular calcium following FcεRI crosslinking and A23187 treatment suggesting it acts on the signals controlling granule release. An E. purpurea root extract and a fraction with high alkylamide content derived from this extract also displayed these activities while fractions with little to no detectable amounts of alkylamide did not. A15 mediated inhibition of calcium influx was not limited to mast cells as A23187-stimulated calcium

  18. Development of anti-scale poly(aspartic acid-citric acid) dual polymer systems for water treatment.

    PubMed

    Nayunigari, Mithil Kumar; Gupta, Sanjay Kumar; Kokkarachedu, Varaprasad; Kanny, K; Bux, F

    2014-01-01

    The formation of calcium sulphate and calcium carbonate scale poses major problems in heat exchangers and water cooling systems, thereby affecting the performance of these types of equipment. In order to inhibit these scale formations, new types of biodegradable water soluble single polymer and dual poly(aspartic acid-citric acid) polymers were developed and tested. The effectiveness of single polymer and four different compositions of poly aspartic acid and citric acid dual polymer systems as scale inhibitors were evaluated. Details of the synthesis, thermal stability, scale inhibition and the morphological characterization of single and dual polymers are presented in this scientific paper. It was found that the calcium sulphate scale inhibition rate was in the range 76.06-91.45%, while the calcium carbonate scale inhibition rate observed was in the range 23.37-30.0% at 65-70 °C. The finding suggests that the water soluble dual polymers are very effective in sulphate scale inhibition in comparison of calcium carbonate scale inhibition.

  19. Ascorbic acid induces alkaline phosphatase, type X collagen, and calcium deposition in cultured chick chondrocytes.

    PubMed

    Leboy, P S; Vaias, L; Uschmann, B; Golub, E; Adams, S L; Pacifici, M

    1989-10-15

    During the process of endochondral bone formation, proliferating chondrocytes give rise to hypertrophic chondrocytes, which then deposit a mineralized matrix to form calcified cartilage. Chondrocyte hypertrophy and matrix mineralization are associated with expression of type X collagen and the induction of high levels of the bone/liver/kidney isozyme of alkaline phosphatase. To determine what role vitamin C plays in these processes, chondrocytes derived from the cephalic portion of 14-day chick embryo sternae were grown in the absence or presence of exogenous ascorbic acid. Control untreated cells displayed low levels of type X collagen and alkaline phosphatase activity throughout the culture period. However, cells grown in the presence of ascorbic acid produced increasing levels of alkaline phosphatase activity and type X collagen mRNA and protein. Both alkaline phosphatase activity and type X collagen mRNA levels began to increase within 24 h of ascorbate treatment; by 9 days, the levels of both alkaline phosphatase activity and type X collagen mRNA were 15-20-fold higher than in non-ascorbate-treated cells. Ascorbate treatment also increased calcium deposition in the cell layer and decreased the levels of types II and IX collagen mRNAs; these effects lagged significantly behind the elevation of alkaline phosphatase and type X collagen. Addition of beta-glycerophosphate to the medium increased calcium deposition in the presence of ascorbate but had no effect on levels of collagen mRNAs or alkaline phosphatase. The results suggest that vitamin C may play an important role in endochondral bone formation by modulating gene expression in hypertrophic chondrocytes.

  20. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean

    2011-01-01

    Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

  1. Surface modification of calcium hydroxyapatite by grafting of etidronic acid

    NASA Astrophysics Data System (ADS)

    Othmani, Masseoud; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi

    2013-06-01

    The surface of prepared calcium hydroxyapatite CaHAp has been modified by grafting the etidronic acid (ETD). For that purpose, CaHAp powders have been suspended in an aqueous etidronate solution with different concentrations. The obtained composites CaHAp-(ETD) were characterized by TEM and AFM techniques to determinate morphological properties and were also characterized by XRD, IR, NMR and chemical and thermal analysis to determinate their physico-chemical properties and essentially the nature of the interaction between the inorganic support and the grafted organic ETD. After reaction with ETD, XRD powder analysis shows that the apatitic structure remains unchanged with slight affectation of its crystallinity. The presence of etidronate fragment bounded to hydroxyapatite was confirmed by IR and solid-state NMR spectroscopy. TEM and AFM techniques indicate that the presence of etidronate changes the morphology of the particles. Basing on the obtained results, a reactional mechanism was proposed to explain the formation of covalent Casbnd Osbnd Porg bonds on the hydroxyapatite surface between the superficial hydroxyl groups (tbnd Casbnd OH) of the apatite and phosphonate group (Psbnd OH) of etidronate.

  2. Effect of Intermittent Exposure to 3% CO2 on Respiration, Acid-Base Balance, and Calcium-Phosphorus Metabolism

    DTIC Science & Technology

    1978-03-01

    of the renal functions primarily involved in acid- base regulations are shown in Fig. 7. There was an immediate response to C02 breathing on the first...1965). Based on the available data, it is not possible to explain why the renal response was turned off on Day 2. At the fourth and fifth days... base balance, and calcium-phosphorus metabolism K. E. SCHAEFER, C. R. CAREY, J. H. DOUGHERTY, JR., C. MORGAN, and A. A. MESSIER Naval Submarine

  3. Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

    PubMed Central

    Cai, Xixi; Lin, Jiaping; Wang, Shaoyun

    2016-01-01

    Peptide-calcium can probably be a suitable supplement to improve calcium absorption in the human body. In this study, a specific peptide Phe-Tyr (FY) with calcium-binding capacity was purified from Schizochytrium sp. protein hydrolysates through gel filtration chromatography and reversed phase HPLC. The calcium-binding capacity of FY reached 128.77 ± 2.57 μg/mg. Results of ultraviolet spectroscopy, fluorescence spectroscopy, and infrared spectroscopy showed that carboxyl groups, amino groups, and amido groups were the major chelating sites. FY-Ca exhibited excellent thermal stability and solubility, which were beneficial to be absorbed and transported in the basic intestinal tract of the human body. Moreover, the calcium bioavailability in Caco-2 cells showed that FY-Ca could enhance calcium uptake efficiency by more than three times when compared with CaCl2, and protect calcium ions against dietary inhibitors, such as tannic acid, oxalate, phytate, and Zn2+. Our findings further the progress of algae-based peptide-calcium, suggesting that FY-Ca has the potential to be developed as functionally nutraceutical additives. PMID:28036002

  4. Effect of fruit on net acid and urinary calcium excretion in an acute feeding trial of women.

    PubMed

    Bell, Janet Amy; Whiting, Susan Joyce

    2004-05-01

    Consumption of fruits and vegetables has been implicated in lowering net acid excretion (NAE), but few studies have directly examined NAE and urinary calcium effects. Further, there is no evidence that only fresh fruits and vegetables must be consumed for a beneficial effect on bone. A crossover, acute-load study was designed to investigate whether processed fruit was as effective as fresh fruit in reducing NAE and protein-induced hypercalciuria. Fifteen women completed three dietary treatments on three different mornings. A fasting urine sample was collected before consuming one of the following three isocaloric high-protein treatments: control, fresh apples, and processed applesauce. The serving size for the applesauce treatment was 2.5 times that for fresh apples. Urine was collected at baseline (0 h) and at 1.5, 3.0, and 4.5 h. Compared with baseline, NAE increased after control treatment but decreased after fresh or processed apple treatment (P = 0.041). Calcium excretion increased with all treatments by 3 h; however, the increase was less for fresh apple and applesauce (P = 0.024). In an acute feeding model, fruit intake reduced NAE and urinary calcium excretion. Processed fruit appears to be effective, although a larger serving size was needed than with fresh fruit.

  5. Fatty acid bile acid conjugates (FABACs)—New molecules for the prevention of cholesterol crystallisation in bile

    PubMed Central

    Gilat, T; Somjen, G; Mazur, Y; Leikin-Frenkel, A; Rosenberg, R; Halpern, Z; Konikoff, F.

    2001-01-01

    BACKGROUND—Cholesterol gall stones are a frequent disease for which at present surgery is the usual therapy. Despite the importance of bile acids it has become evident that phospholipids are the main cholesterol solubilisers in bile. Even phospholipid components, such as fatty acids, have anticrystallising activity.
AIM—To synthesise fatty acid bile acid conjugates (FABACs) and study their effects on cholesterol crystallisation in bile in vitro and in vivo.
METHODS—FABACs were prepared by conjugation of cholic acid at position 3 with saturated fatty acids of variable chain length using an amide bond. Cholesterol crystallisation and its kinetics (crystal observation time, crystal mass) were studied in model bile, pooled enriched human bile, and fresh human bile using FABACs with saturated fatty acids of varying chain length (C-6 to C-22). Absorption of FABACs into blood and bile was tested in hamsters. Prevention of biliary cholesterol crystallisation in vivo was tested in hamsters and inbred mice.
RESULTS—FABACs strongly inhibited cholesterol crystallisation in model as well as native bile. The FABACs with longer acyl chains (C-16 to C-22) were more effective. At a concentration of 5 mM, FABACs almost completely inhibited cholesterol crystallisation in fresh human bile for 21 days. FABACs were absorbed and found in both portal and heart blood of hamsters. Levels in bile were 2-3 times higher than in blood, indicating active secretion. Appreciable levels were found in the systemic circulation 24-48 hours after a single administration. Ingested FABACs completely prevented the formation of cholesterol crystals in the gall bladders of hamsters and mice fed a lithogenic diet.
CONCLUSIONS—FABACs are potent inhibitors of cholesterol crystallisation in bile. They are absorbed and secreted into bile and prevent the earliest step of cholesterol gall stone formation in animals. These compounds may be of potential use in cholesterol gall stone disease in

  6. Alterations in cytosol free calcium in horseradish roots simultaneously exposed to lanthanum(III) and acid rain.

    PubMed

    Zhang, Xuanbo; Wang, Lihong; Zhou, Anhua; Zhou, Qing; Huang, Xiaohua

    2016-04-01

    The extensive use of rare earth elements (REEs) has increased their environmental levels. REE pollution concomitant with acid rain in many agricultural regions can affect crop growth. Cytosol free calcium ions (Ca(2+)) play an important role in almost all cellular activities. However, no data have been reported regarding the role of cytosol free Ca(2+) in plant roots simultaneously exposed to REE and acid rain. In this study, the effects of exposures to lanthanum(III) and acid rain, independently and in combination, on cytosol free Ca(2+) levels, root activity, metal contents, biomass, cytosol pH and La contents in horseradish roots were investigated. The simultaneous exposures to La(III) and acid rain increased or decreased the cytosol free Ca(2+) levels, depending on the concentration of La(III), and these effects were more evident than independent exposure to La(III) or acid rain. In combined exposures, cytosol free Ca(2+) played an important role in the regulation of root activity, metal contents and biomass. These roles were closely related to La(III) dose, acid rain strength and treatment mode (independent exposure or simultaneous exposure). A low concentration of La(III) (20 mg L(-1)) could alleviate the adverse effects on the roots caused by acid rain, and the combined exposures at higher concentrations of La(III) and acid rain had synergic effects on the roots. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Characterization of metabolic network of oxalic acid biosynthesis through RNA seq data analysis of developing spikes of finger millet (Eleusine coracana): Deciphering the role of key genes involved in oxalate formation in relation to grain calcium accumulation.

    PubMed

    Akbar, Naved; Gupta, Supriya; Tiwari, Apoorv; Singh, K P; Kumar, Anil

    2018-04-05

    In the present study, we identified seven major genes of oxalic acid biosynthesis pathway (SGAT, GGAT, ICL, GLO, MHAR, APO and OXO) from developing spike transcriptome of finger millet using rice as a reference. Sequence alignment of identified genes showed high similarity with their respective homolog in rice except for OXO and GLO. Transcript abundance (FPKM) reflects the higher accumulation of identified genes in GP-1 (low calcium genotype) as compared to GP-45 (high calcium genotype) which was further confirmed by qRT-PCR analysis, indicating differential oxalate formation in both genotypes. Determination of oxalic acid and tartaric acid content in developing spikes explain that higher oxalic acid content in GP-1 however, tartaric acid content was more in GP-45. Higher calcium content in GP-45 and lower oxalate accumulation may be due to the diversion of more ascorbic acid into tartaric acid and may correspond to less formation of calcium oxalate. Our results suggest that more than one pathway for oxalic acid biosynthesis might be present in finger millet with probable predominance of ascorbate-tartarate pathway rather than glyoxalate-oxalate conversion. Thus, finger millet can be use as an excellent model system for understanding more specific role of nutrients-antinutrients interactions, as evident from the present study. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Calcium Silicate/Chitosan-Coated Electrospun Poly (Lactic Acid) Fibers for Bone Tissue Engineering.

    PubMed

    Su, Chu-Jung; Tu, Ming-Gene; Wei, Li-Ju; Hsu, Tuan-Ti; Kao, Chia-Tze; Chen, Tsui-Han; Huang, Tsui-Hsien

    2017-05-05

    Electrospinning technology allows fabrication of nano- or microfibrous fibers with inorganic and organic matrix and it is widely applied in bone tissue engineering as it allows precise control over the shapes and structures of the fibers. Natural bone has an ordered composition of organic fibers with dispersion of inorganic apatite among them. In this study, poly (lactic acid) (PLA) mats were fabricated with electrospinning and coated with chitosan (CH)/calcium silicate (CS) mixer. The microstructure, chemical component, and contact angle of CS/CH-PLA composites were analyzed by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, various CS/CH-coated PLA mats increased the formation of hydroxyapatite on the specimens' surface when soaked in cell cultured medium. During culture, several biological characteristics of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA groups were promoted as compared to those on pure PLA mat. Increased secretion levels of Collagen I and fibronectin were observed in calcium silicate-powder content. Furthermore, with comparison to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs and their osteogenesis properties, which was characterized by osteogenic-related gene expression. These results clearly demonstrated that the biodegradable and electroactive CS/CH-PLA composite mats are an ideal and suitable candidate for bone tissue engineering.

  9. Idiopathic hypercalciuria and formation of calcium renal stones

    PubMed Central

    Coe, Fredric L.; Worcester, Elaine M.; Evan, Andrew P.

    2018-01-01

    The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall’s plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is <400 mg per day, and treatment with potassium citrate has been used to prevent stones. Urine calcium levels >200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone diseas PMID:27452364

  10. Isolation and identification of calcium-chelating peptides from Pacific cod skin gelatin and their binding properties with calcium.

    PubMed

    Wu, Wenfei; Li, Bafang; Hou, Hu; Zhang, Hongwei; Zhao, Xue

    2017-12-13

    A calcium-chelating peptide is considered to have the ability to improve calcium absorption. In this study, Pacific cod skin gelatin hydrolysates treated with trypsin for 120 min exhibited higher calcium-chelating activity. Sequential chromatography, involving hydroxyapatite affinity chromatography and reversed phase high performance liquid chromatography, was used for the purification of calcium-chelating peptides. Two novel peptides with the typical characteristics of collagen were sequenced as GDKGESGEAGER and GEKGEGGHR based on LC-HRMS/MS, which showed a high affinity to calcium. Calcium-peptide complexation was further characterized by ESI-MS (MS and MS/MS) and FTIR spectroscopy. The results showed that the complexation of the two peptides with calcium was conducted mainly at the ratio of 1 : 1. The amino terminal group and the peptide bond of the peptide backbone as well as the amino group of the lysine side chain and the carboxylate of the glutamate side chain were the possible calcium binding sites for the two peptides. Meanwhile, several amino acid side chain groups, including the hydroxyl (Ser) and carboxylate (Asp) of GDKGESGEAGER and the imine (His) of GEKGEGGHR, were crucial in the complexation. The arginine residue in GEKGEGGHR also participated in the calcium coordination. Additionally, several active fragments with calcium-chelating activity were obtained using MS/MS spectra, including GDKGESGEAGE, GEAGER, GEK, EKG and KGE. This study suggests that gelatin-derived peptides have the potential to be used as a calcium-chelating ingredient to combat calcium deficiency.

  11. High butyric acid amounts induce oxidative stress, alter calcium homeostasis, and cause neurite retraction in nerve growth factor-treated PC12 cells.

    PubMed

    Cueno, Marni E; Kamio, Noriaki; Seki, Keisuke; Kurita-Ochiai, Tomoko; Ochiai, Kuniyasu

    2015-07-01

    Butyric acid (BA) is a common secondary metabolite by-product produced by oral pathogenic bacteria and is detected in high amounts in the gingival tissue of patients with periodontal disease. Previous works have demonstrated that BA can cause oxidative stress in various cell types; however, this was never explored using neuronal cells. Here, we exposed nerve growth factor (NGF)-treated PC1(2) cells to varying BA concentrations (0.5, 1.0, 5.0 mM). We measured total heme, H(2)O(2), catalase, and calcium levels through biochemical assays and visualized the neurite outgrowth after BA treatment. Similarly, we determined the effects of other common periodontal short-chain fatty acids (SCFAs) on neurite outgrowth for comparison. We found that high (1.0 and 5.0 mM) BA concentrations induced oxidative stress and altered calcium homeostasis, whereas low (0.5 mM) BA concentration had no significant effect. Moreover, compared to other SCFAs, we established that only BA was able to induce neurite retraction.

  12. Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum.

    PubMed

    Dixit, Ajay Kumar; Jayabaskaran, Chelliah

    2015-05-01

    Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 μM and 120 μM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 μM and 1.7 μM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1. Copyright © 2015 Elsevier GmbH. All rights reserved.

  13. Equilibrium constant for calcium ion and ascorbate ion.

    PubMed

    Tsao, C S

    1984-02-15

    The combination of calcium and ascorbic acid in water at 25 degrees C has been examined by measuring the change of free calcium ion concentration as ascorbate was added in small increment to a solution of calcium. The data show clearly that complex formation between calcium ion and ascorbate ion occurred. At ionic strength mu = 0.1-0.2, the equilibrium constant of Ca++ and the singly-charged ascorbate ion has been measured to be 2.1 M-1. The precision of the result is better than 5% and the accuracy is estimated to be better than 20%. The application of the equilibrium constants is discussed.

  14. Calcium supplementation in osteoporosis: useful or harmful?

    PubMed

    Chiodini, Iacopo; Bolland, Mark J

    2018-04-01

    Osteoporosis and fragility fractures are important social and economic problems worldwide and are due to both the loss of bone mineral density and sarcopenia. Indeed, fragility fractures are associated with increased disability, morbidity and mortality. It is known that a normal calcium balance together with a normal vitamin D status is important for maintaining well-balanced bone metabolism, and for many years, calcium and vitamin D have been considered crucial in the prevention and treatment of osteoporosis. However, recently, the usefulness of calcium supplementation (alone or with concomitant vitamin D) has been questioned, since some studies reported only weak efficacy of these supplementations in reducing fragility fracture risk. On the other hand, besides the gastrointestinal side effects of calcium supplements and the risk of kidney stones related to use of co-administered calcium and vitamin D supplements, other recent data suggested potential adverse cardiovascular effects from calcium supplementation. This debate article is focused on the evidence regarding both the possible usefulness for bone health and the potential harmful effects of calcium and/or calcium with vitamin D supplementation. © 2018 European Society of Endocrinology.

  15. Supplemental Vitamins and Minerals for CVD Prevention and Treatment.

    PubMed

    Jenkins, David J A; Spence, J David; Giovannucci, Edward L; Kim, Young-In; Josse, Robert; Vieth, Reinhold; Blanco Mejia, Sonia; Viguiliouk, Effie; Nishi, Stephanie; Sahye-Pudaruth, Sandhya; Paquette, Melanie; Patel, Darshna; Mitchell, Sandy; Kavanagh, Meaghan; Tsirakis, Tom; Bachiri, Lina; Maran, Atherai; Umatheva, Narmada; McKay, Taylor; Trinidad, Gelaine; Bernstein, Daniel; Chowdhury, Awad; Correa-Betanzo, Julieta; Del Principe, Gabriella; Hajizadeh, Anisa; Jayaraman, Rohit; Jenkins, Amy; Jenkins, Wendy; Kalaichandran, Ruben; Kirupaharan, Geithayini; Manisekaran, Preveena; Qutta, Tina; Shahid, Ramsha; Silver, Alexis; Villegas, Cleo; White, Jessica; Kendall, Cyril W C; Pichika, Sathish C; Sievenpiper, John L

    2018-06-05

    The authors identified individual randomized controlled trials from previous meta-analyses and additional searches, and then performed meta-analyses on cardiovascular disease outcomes and all-cause mortality. The authors assessed publications from 2012, both before and including the U.S. Preventive Service Task Force review. Their systematic reviews and meta-analyses showed generally moderate- or low-quality evidence for preventive benefits (folic acid for total cardiovascular disease, folic acid and B-vitamins for stroke), no effect (multivitamins, vitamins C, D, β-carotene, calcium, and selenium), or increased risk (antioxidant mixtures and niacin [with a statin] for all-cause mortality). Conclusive evidence for the benefit of any supplement across all dietary backgrounds (including deficiency and sufficiency) was not demonstrated; therefore, any benefits seen must be balanced against possible risks. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Sphingomyelin-induced inhibition of the plasma membrane calcium ATPase causes neurodegeneration in type A Niemann-Pick disease.

    PubMed

    Pérez-Cañamás, A; Benvegnù, S; Rueda, C B; Rábano, A; Satrústegui, J; Ledesma, M D

    2017-05-01

    Niemann-Pick disease type A (NPA) is a rare lysosomal storage disorder characterized by severe neurological alterations that leads to death in childhood. Loss-of-function mutations in the acid sphingomyelinase (ASM) gene cause NPA, and result in the accumulation of sphingomyelin (SM) in lysosomes and plasma membrane of neurons. Using ASM knockout (ASMko) mice as a NPA disease model, we investigated how high SM levels contribute to neural pathology in NPA. We found high levels of oxidative stress both in neurons from these mice and a NPA patient. Impaired activity of the plasma membrane calcium ATPase (PMCA) increases intracellular calcium. SM induces PMCA decreased activity, which causes oxidative stress. Incubating ASMko-cultured neurons in the histone deacetylase inhibitor, SAHA, restores PMCA activity and calcium homeostasis and, consequently, reduces the increased levels of oxidative stress. No recovery occurs when PMCA activity is pharmacologically impaired or genetically inhibited in vitro. Oral administration of SAHA prevents oxidative stress and neurodegeneration, and improves behavioral performance in ASMko mice. These results demonstrate a critical role for plasma membrane SM in neuronal calcium regulation. Thus, we identify changes in PMCA-triggered calcium homeostasis as an upstream mediator for NPA pathology. These findings can stimulate new approaches for pharmacological remediation in a disease with no current clinical treatments.

  17. Long-chain α,ω-dioic acids as inducers of cyclosporin A-insensitive nonspecific permeability of the inner membrane of liver mitochondria loaded with calcium or strontium ions.

    PubMed

    Dubinin, M V; Adakeeva, S I; Samartsev, V N

    2013-04-01

    Long-chain saturated monocarboxylic fatty acids can induce nonspecific permeability of the inner membrane (open pores) of liver mitochondria loaded with Ca2+ or Sr(2+) by the mechanism insensitive to cyclosporin A. In this work we investigated the effect of their metabolites - α,ω-dioic (dicarboxylic) acids - as potential inducers of pore opening by a similar mechanism. It was established that the addition of α,ω-hexadecanedioic acid (HDA) at a concentration of 10-30 µM to liver mitochondria loaded with Ca2+ or Sr(2+) leads to swelling of the organelles and release of these ions from the matrix. The maximum effect of HDA is observed at 50 µM Ca2+ concentration. Cyclosporin A at a concentration of 1 µM, previously added to the mitochondria, did not inhibit the observed processes. The calcium uniporter inhibitor ruthenium red, which blocks influx of Ca2+ and Sr(2+) to the matrix of mitochondria, prevented HDA-induced swelling. The effect of HDA as inducer of swelling of mitochondria was compared with similar effects of α,ω-tetradecanedioic and α,ω-dodecanedioic acids whose acyl chains are two and four carbon atoms shorter than HDA, respectively. It was found that the efficiency of these α,ω-dioic acids decreases with reducing number of carbon atoms in their acyl chains. It was concluded that in the presence of Ca2+ or Sr(2+) long-chain saturated α,ω-dioic acids can induce a cyclosporin A-insensitive permeability of the inner membrane (open pores) of liver mitochondria as well as their monocarboxylic analogs.

  18. Young Adults' Perceptions of Calcium Intake and Health: A Qualitative Study

    ERIC Educational Resources Information Center

    Marcinow, Michelle L.; Randall Simpson, Janis A.; Whiting, Susan J.; Jung, Mary E.; Buchholz, Andrea C.

    2017-01-01

    Many young Canadian adults are not meeting dietary calcium recommendations. This is concerning as adequate calcium is important throughout young adulthood to maximize peak bone mass for osteoporosis prevention. There are limited studies that have explored young adults' perceptions toward calcium and health. Our objectives were to determine young…

  19. Calcium requirements for Asian children and adolescents.

    PubMed

    Lee, Warren Tak Keung; Jiang, Ji

    2008-01-01

    Calcium is important for bone health. Over the last 15 years, reference calcium intakes in Western countries have been revised upwards for maximizing bone mass at skeletal maturity and for prevention of osteoporotic fractures. Some of these reference figures have also been adopted for use in Asian countries. However, the scientific data based on for revising reference calcium intakes in the West was largely based on Caucasians. Limited human studies relating to calcium requirements and bone mineralization have been conducted in Asians in Asia. In children and adolescents, a trial has confirmed no effects of calcium supplementation on bone gains in adolescent girls after 7 years. A meta-analysis has also revealed that calcium supplementation has little beneficial effects on bone gain. Given that genetic factors, hormonal status, body size, bone structure, diets, physical activity, vitamin D status and adaptation could modify calcium retention and bone integrity, these factors need to be considered collectively to promote bone health in Asian populations. Furthermore, studies to identify indigenous foods rich in calcium and high in bioavailability are needed to widen sources of dietary calcium. Ethnic differences in calcium retention, hormonal status, bone structure, bone mineral accretion and peak bone mass are evident among Asians, Caucasians and Blacks in USA. Hence, reference calcium intakes for Asians are likely to be unique and different from those of Caucasians. More research has to be conducted in Asian populations in order to develop appropriate reference calcium intakes for the region.

  20. Dairy Products, Dietary Calcium and Bone Health: Possibility of Prevention of Osteoporosis in Women: The Polish Experience

    PubMed Central

    Wadolowska, Lidia; Sobas, Kamila; Szczepanska, Justyna W.; Slowinska, Malgorzata A.; Czlapka-Matyasik, Magdalena; Niedzwiedzka, Ewa

    2013-01-01

    The objective of the study was to analyze the consumption of dairy products and dietary calcium by women in the context of bone mineral density and to assess opportunities to prevent osteoporosis in a dietary manner. The study was carried out with 712 Polish women. In 170 women aged 32 to 59 bone mineral density (BMD) was measured. The data on the consumption of dairy products and dietary calcium and some other osteoporosis risk factors was collected from 712 women. The average calcium intake from a diet was 507 mg/day. Only 2% of the women met Polish calcium intake recommendations. During adulthood, dairy product consumption or dietary calcium intake did not differ significantly between women with low BMD (below −1 SD) and women with regular BMD (≥−1 SD) (47.4 vs. 44.3 servings/week and 459 vs. 510 mg/day, respectively, p > 0.05). The odds ratios adjusted for age, menstruation and BMI in women with upper BMD tercile in comparison to the reference group (bottom tercile) was 2.73 (95% CI: 1.14, 6.55; p < 0.05) for the daily consumption of dairy products during the pre-school period and 2.40 (95% CI: 1.01, 5.70; p < 0.05) for the daily consumption of dairy products during the school period. Two clusters of women were established. In the S1 cluster, low BMD (below −1 SD) was associated with older age (≥50 years), lack of menstrual cycle. In the S2 cluster, regular BMD (≥−1 SD) was related to younger aged women (<50 years), presence of menstrual cycle, consumption of higher level of dairy products (≥28 servings/week) during adulthood and daily intake of dairy products during childhood and adolescence. The results indicate that good bone health to the large extent depended upon the combined impact of dietary factors and some non-modifiable risk factors of osteoporosis such as age and the presence of menstruation. Consumption of dairy products in childhood and adolescence may improve bone mineral density and reduce the risk of osteoporosis in adult women

  1. Ursodeoxycholic and deoxycholic acids: A good and a bad bile acid for intestinal calcium absorption.

    PubMed

    Rodríguez, Valeria; Rivoira, María; Marchionatti, Ana; Pérez, Adriana; Tolosa de Talamoni, Nori

    2013-12-01

    The aim of this study was to investigate the effect of ursodeoxycholic acid (UDCA) on intestinal Ca(2+) absorption and to find out whether the inhibition of this process caused by NaDOC could be prevented by UDCA. Chicks were employed and divided into four groups: (a) controls, (b) treated with 10mM NaDOC, (c) treated with 60 μg UDCA/100g of b.w., and (d) treated with 10mM NaDOC and 60 μg UDCA/100g of b.w. UDCA enhanced intestinal Ca(2+) absorption, which was time and dose-dependent. UDCA avoided the inhibition of intestinal Ca(2+) absorption caused by NaDOC. Both bile acids altered protein and gene expression of molecules involved in the transcellular pathway of intestinal Ca(2+) absorption, but in the opposite way. UDCA aborted the oxidative stress produced by NaDOC in the intestine. UDCA and UDCA plus NaDOC increased vitamin D receptor protein expression. In conclusion, UDCA is a beneficial bile acid for intestinal Ca(2+) absorption. Contrarily, NaDOC inhibits the intestinal cation absorption through triggering oxidative stress. The use of UDCA in patients with cholestasis would be benefited because of the protective effect on the intestinal Ca(2+) absorption, avoiding the inhibition caused by hydrophobic bile acids and neutralizing the oxidative stress. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Comparing the moisturizing effects of ascorbic acid and calcium ascorbate against that of tocopherol in emulsions.

    PubMed

    Gönüllü, U; Sensoy, D; Uner, M; Yener, G; Altinkurt, T

    2006-01-01

    Calcium ascorbate (CAAS), which is a hydrophilic and stable derivative of ascorbic acid (vitamin C) (AA), is commonly used in foods as an antioxidative agent. There are very limited reports on its dermatological use in the literature. In this paper, it is reported that CAAS could be used in place of ascorbic acid, which has chemical stability problems in topicals due to degradation by oxidation. The aim of this study was to investigate the skin-hydrating effect of CAAS compared to those of ascorbic acid and tocopherol (vitamin E) (T), which is a potential skin moisturizer and commonly used in dermocosmetics. Vitamins are incorporated into two kinds of base creams (o/w and w/o emulsion creams), alone and in combinations. Formulations were applied to the inner forearms of volunteers, and skin conductance was measured by using a corneometer. Data obtained were statistically evaluated. It was found that the skin-hydrating effect of CAAS was higher than that of AA and lower than that of T. However, its effect was very close to that of T.

  3. Ferulic acid relaxed rat aortic, small mesenteric and coronary arteries by blocking voltage-gated calcium channel and calcium desensitization via dephosphorylation of ERK1/2 and MYPT1.

    PubMed

    Zhou, Zhong-Yan; Xu, Jia-Qi; Zhao, Wai-Rong; Chen, Xin-Lin; Jin, Yu; Tang, Nuo; Tang, Jing-Yi

    2017-11-15

    Ferulic acid, a natural ingredient presents in several Chinese Materia Medica such as Radix Angelicae Sinensis, has been identified as an important multifunctional and physiologically active small molecule. However, its pharmacological activity in different blood vessel types and underlying mechanisms are unclear. The present study was to investigate the vascular reactivity and the possible action mechanism of FA on aorta, small mesenteric arteries and coronary arteries isolated from Wistar rats. We found FA dose-dependently relieved the contraction of aorta, small mesenteric arteries and coronary arteries induced by different contractors, U46619, phenylephrine (Phe) and KCl. The relaxant effect of FA was not affected by L-NAME (eNOS inhibitor), ODQ (soluble guanylate cyclase inhibitor), and mechanical removal of endothelium in thoracic aortas. The contraction caused by 60mM KCl (60K) was concentration-dependently hindered by FA pretreatment in all three types of arteries. In Ca 2+ -free 60K solution, FA weakened Ca 2+ -related contraction in a concentration dependent manner. And FA relaxed both fluoride and phorbol ester which were PKC, ERK and Rho-kinase activators induced contraction in aortic rings with or without Ca 2+ in krebs solution. Western blotting experiments in A7r5 cells revealed that FA inhibited calcium sensitization via dephosphorylation of ERK1/2 and MYPT1. Furthermore, the relaxation effect of FA was attenuated by verapamil (calcium channel blocker), ERK inhibitor, and fasudil (ROCK inhibitor). These results provide evidence that FA exhibits endothelium-independent vascular relaxant effect in different types of arteries. The molecular mechanism of vasorelaxation activity of FA probably involved calcium channel inhibition and calcium desensitization. Copyright © 2017. Published by Elsevier B.V.

  4. Clarithromycin and tetracycline binding to soil humic acid in the absence and presence of calcium

    NASA Astrophysics Data System (ADS)

    Christl, Iso; Ruiz, Mercedes; Schmidt, J. R.; Pedersen, Joel A.

    2017-04-01

    Many organic micropollutants including antibiotics contain positively charged moieties and are present as organic cations or zwitterions at environmentally relevant pH conditions. In this study, we investigated the pH-, ionic strength-, and concentration-dependent binding of the two antibiotics clarithromycin and tetracycline to dissolved humic acid in the absence and presence of Ca2+. The investigated compounds strongly differ in their chemical speciation. Clarithromycin can be present as neutral and cationic species, only. But tetracycline can form cations, zwitterions as well as anions and is able to form various calcium complexes. The pH-dependence of binding to soil humic acid was observed to be strongly linked to the protonation behavior for both antibiotics. The presence of Ca2+ decreased clarithromycin binding to soil humic acid, but increased tetracycline binding with increasing Ca2+ concentration. The experimental observations were well described with the NICA-Donnan model considering the complete aqueous speciation of antibiotics and allowing for binding of cationic and zwitterionic species to soil humic acid. Our results indicate that clarithromycin is subject to competition with Ca2+ for binding to soil humic acid and that the electrostatic interaction of positively charged tetracycline-Ca complexes with humic acid enhances tetracycline binding in presence of Ca2+ rather than the formation of ternary complexes, except at very low tetracycline concentrations. We conclude that for the description of ionizable organic micropollutant binding to dissolved natural organic matter, the complete speciation of both sorbate and sorbent has to be considered.

  5. Liquid Paraffin vs Hyaluronic Acid in Preventing Intraperitoneal Adhesions.

    PubMed

    Kataria, Hanish; Singh, Vinod Prem

    2017-12-01

    Adhesion formation after abdominal and pelvic operations remains a challenging problem. Role of adjuvant barriers have been studied but there is no comparative study between liquid paraffin and hyaluronic acid as a barrier method. Hence, we planned to compare the effectiveness of 0.4 % hyaluronic acid and liquid paraffin in the prevention of postoperative intraperitoneal adhesions in rats. This prospective, randomized and controlled study was conducted in 60 adult Wistar albino rats. Surgical trauma by caecal abrasion and 1 g talcum powder was used in the rat model to induce adhesion formation. After trauma, 3 ml normal saline was instilled in the peritoneal cavity in control group ( n  = 20), 3 ml liquid paraffin was instilled in experimental group A ( n  = 20) and 3 ml 0.4 % hyaluronic acid was instilled in experimental group B ( n  = 20). Two weeks after laparotomy, repeat laparotomy was performed and the adhesions were scored according to Zuhlke classification. Liquid paraffin and hyaluronic acid both reduce the extent and grade of adhesions both macroscopically ( p  = 0.018, p  = 0.017) and microscopically ( p  = 0.019, p  = 0.019) respectively. Although there was significant reduction in adhesions by hyaluronic acid at certain specific sites as compared with liquid paraffin, its overall effectiveness in preventing postoperative intraperitoneal adhesions is not significantly different from liquid paraffin ( p  = 0.092, p  = 0.193) respectively. The presence of liquid paraffin and hyaluronic acid in the peritoneal cavity reduce postoperative intraperitoneal adhesions significantly in rats. However, there is no overall significant difference in the effectiveness of two groups. Dosage and safety of these chemicals in human beings remains to be established.

  6. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., CAS Reg. No. 814-80-2) is prepared commercially by the neutralization of lactic acid with calcium.... (d) Prior sanctions for this ingredient different from the uses established in this section do not...

  7. Mineralisation of reconstituted collagen using polyvinylphosphonic acid/polyacrylic acid templating matrix protein analogues in the presence of calcium, phosphate and hydroxyl ions

    PubMed Central

    Kim, Young Kyung; Gu, Li-sha; Bryan, Thomas E.; Kim, Jong Ryul; Chen, Liang; Liu, Yan; Yoon, James C.; Breschi, Lorenzo; Pashley, David H.; Tay, Franklin R.

    2010-01-01

    The complex morphologies of mineralised collagen fibrils are regulated through interactions between the collagen matrix and non-collagenous extracellular proteins. In the present study, polyvinylphosphonic acid, a biomimetic analogue of matrix phosphoproteins, was synthesised and confirmed with FTIR and NMR. Biomimetic mineralisation of reconstituted collagen fibrils devoid of natural non-collagenous proteins was demonstrated with TEM using a Portland cement-containing resin composite and a phosphate-containing fluid in the presence of polyacrylic acid as sequestration, and polyvinylphosphonic acid as templating matrix protein analogues. In the presence of these dual biomimetic analogues in the mineralisation medium, intrafibrillar and extrafibrillar mineralisation via bottom-up nanoparticle assembly based on the nonclassical crystallisation pathway could be identified. Conversely, only large mineral spheres with no preferred association with collagen fibrils were observed in the absence of biomimetic analogues in the medium. Mineral phases were evident within the collagen fibrils as early as 4 hours after the initially-formed amorphous calcium phosphate nanoprecursors were transformed into apatite nanocrystals. Selected area electron diffraction patterns of highly mineralised collagen fibrils were nearly identical to those of natural bone, with apatite crystallites preferentially aligned along the collagen fibril axes. PMID:20621767

  8. Chlorhexidine Prevents Root Dentine Mineral Loss and Fracture Caused by Calcium Hydroxide over Time

    PubMed Central

    Thomaz, Érika Bárbara Abreu Fonseca; Lima, Darlon Martins; Bauer, José

    2017-01-01

    Purpose. To evaluate the mineral ion loss of root dentine after treatment with 2% chlorhexidine solution (CHX) and to compare its yield and flexural strength (fs) after exposure to calcium hydroxide [Ca(OH)2]. Materials and Methods. Dentine bars (DB) were made from 90 roots of bovine incisors and randomized into three groups: GControl: distilled/deionized water (DDW), GNaOCl: 2.5% sodium hypochlorite + 17% EDTA, and GCHX: CHX + DDW. The release of phosphate (PO4) and calcium (Ca) ions was measured by spectrophotometry. The DB were exposed to Ca(OH)2 paste for 0, 30, 90, and 180 days. DB were subjected to the three-point bending test to obtain yield and fs values. The fracture patterns were evaluated (20x). Data were analyzed using Kruskal-Wallis and Dunn's post hoc tests or one- and two-way ANOVA followed by Tukey's post hoc test (α = 0.05). Results. GCHX showed lower PO43− and Ca2+ ionic release than GNaOCl (p < 0.001). For yield and fs, GCHX > GNaOCl in all periods (p < 0.001), except for yield strength values on 90 days (p = 0.791). A larger frequency of vertical fractures was observed in GNaOCl and that of oblique fractures in GCHX (p < 0.05). Conclusions. CHX prevented PO43− and Ca2+ loss and showed a tendency to preserve the yield and fs of root dentine over time following exposure to Ca(OH)2 paste. PMID:28539937

  9. Dysregulation of cellular calcium homeostasis in Alzheimer's disease: bad genes and bad habits.

    PubMed

    Mattson, M P; Chan, S L

    2001-10-01

    Calcium is one of the most important intracellular messengers in the brain, being essential for neuronal development, synaptic transmission and plasticity, and the regulation of various metabolic pathways. The findings reviewed in the present article suggest that calcium also plays a prominent role in the pathogenesis of Alzheimer's disease (AD). Associations between the pathological hallmarks ofAD (neurofibrillary tangles [NFT] and amyloid plaques) and perturbed cellular calcium homeostasis have been established in studies of patients, and in animal and cell culture models of AD. Studies of the effects of mutations in the beta-amyloid precursor protein (APP) and presenilins on neuronal plasticity and survival have provided insight into the molecular cascades that result in synaptic dysfunction and neuronal degeneration in AD. Central to the neurodegenerative process is the inability of neurons to properly regulate intracellular calcium levels. Increased levels of amyloid beta-peptide (Abeta) induce oxidative stress, which impairs cellular ion homeostasis and energy metabolism and renders neurons vulnerable to apoptosis and excitotoxicity. Subtoxic levels of Abeta may induce synaptic dysfunction by impairing multiple signal transduction pathways. Presenilin mutations perturb calcium homeostasis in the endoplasmic reticulum in a way that sensitizes neurons to apoptosis and excitotoxicity; links between aberrant calcium regulation and altered APP processing are emerging. Environmental risk factors for AD are being identified and may include high calorie diets, folic acid insufficiency, and a low level of intellectual activity (bad habits); in each case, the environmental factor impacts on neuronal calcium homeostasis. Low calorie diets and intellectual activity may guard against AD by stimulating production of neurotrophic factors and chaperone proteins. The emerging picture of the cell and molecular biology of AD is revealing novel preventative and therapeutic

  10. Arthritis associated with calcium oxalate crystals in an anephric patient treated with peritoneal dialysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rosenthal, A.; Ryan, L.M.; McCarty, D.J.

    1988-09-02

    The authors report a case of calcium oxalate arthropathy in a woman undergoing intermittent peritoneal dialysis who was not receiving pharmacologic doses of ascorbic acid. She developed acute arthritis, with calcium oxalate crystals in Heberden's and Bouchard's nodes, a phenomenon previously described in gout. Intermittent peritoneal dialysis may be less efficient than hemodialysis in clearing oxalate, and physicians should now consider calcium oxalate-associated arthritis in patients undergoing peritoneal dialysis who are not receiving large doses of ascorbic acid.

  11. Cameleon calcium indicator reports cytoplasmic calcium dynamics in Arabidopsis guard cells

    NASA Technical Reports Server (NTRS)

    Allen, G. J.; Kwak, J. M.; Chu, S. P.; Llopis, J.; Tsien, R. Y.; Harper, J. F.; Schroeder, J. I.; Evans, M. L. (Principal Investigator)

    1999-01-01

    Cytoplasmic free calcium ([Ca2+]cyt) acts as a stimulus-induced second messenger in plant cells and multiple signal transduction pathways regulate [Ca2+]cyt in stomatal guard cells. Measuring [Ca2+]cyt in guard cells has previously required loading of calcium-sensitive dyes using invasive and technically difficult micro-injection techniques. To circumvent these problems, we have constitutively expressed the pH-independent, green fluorescent protein-based calcium indicator yellow cameleon 2.1 in Arabidopsis thaliana (Miyawaki et al. 1999; Proc. Natl. Acad. Sci. USA 96, 2135-2140). This yellow cameleon calcium indicator was expressed in guard cells and accumulated predominantly in the cytoplasm. Fluorescence ratio imaging of yellow cameleon 2.1 allowed time-dependent measurements of [Ca2+]cyt in Arabidopsis guard cells. Application of extracellular calcium or the hormone abscisic acid (ABA) induced repetitive [Ca2+]cyt transients in guard cells. [Ca2+]cyt changes could be semi-quantitatively determined following correction of the calibration procedure for chloroplast autofluorescence. Extracellular calcium induced repetitive [Ca2+]cyt transients with peak values of up to approximately 1.5 microM, whereas ABA-induced [Ca2+]cyt transients had peak values up to approximately 0.6 microM. These values are similar to stimulus-induced [Ca2+]cyt changes previously reported in plant cells using ratiometric dyes or aequorin. In some guard cells perfused with low extracellular KCl concentrations, spontaneous calcium transients were observed. As yellow cameleon 2.1 was expressed in all guard cells, [Ca2+]cyt was measured independently in the two guard cells of single stomates for the first time. ABA-induced, calcium-induced or spontaneous [Ca2+]cyt increases were not necessarily synchronized in the two guard cells. Overall, these data demonstrate that that GFP-based cameleon calcium indicators are suitable to measure [Ca2+]cyt changes in guard cells and enable the pattern of [Ca

  12. Effect of intermittent exposure to 3% CO2 on respiration, acid-base balance, and calcium-phosphorus metabolism.

    PubMed

    Schaefer, K E; Carey, C R; Dougherty, J H; Morgan, C; Messier, A A

    1979-01-01

    One subject was exposed for six days to increasing levels of CO2, rising at a constant rate from 0.03 to 3.0% CO2 within a 15-h period followed by 9 h of air breathing. To assess acid-base parameters, arterialized capillary blood was taken from a finger twice daily (at 8 a.m. and 11 p.m.) at times corresponding to the beginning and end of the intermittent exposure to CO2. Venous blood samples were obtained on alternate days at the same times. Urine specimens were collected twice daily. The subject was on a liquid diet. Resting respiratory minute volume (VE), oxygen consumption (VO2), carbon dioxide excretion (VCO2), alveolar carbon dioxide and oxygen tension (PACO2) and PAO2) were measured twice daily. PACO2 and PAO2 were also determined at the end of breath-holding twice daily; CO2 tolerance tests and lung function tests were also carried out. In contrast to the effects of chronic exposure to 3% CO2, the CO2 tolerance tests showed an increased sensitivity (increase of slope) and breath-holding PACO2 did not change, indicating that acclimatization to CO2 did not develop. The ventilatory response to CO2 was not sufficient to prevent CO2 accumulation in the body; this accumulation was eliminated during the nightly air-breathing periods on the fourth and fifth days, indicated by higher values of PaCO2 and PACO2. The known renal response to hypercapnia, consisting of an increased excretion of titratable acidity, ammonia, and hydrogen ion excretion, occurred but was interrupted after the first day and was triggered again on the fourth and fith days when accumulated CO2 was released from body CO2 stores. The second renal response was associated with a marked calcium excretion, which suggests that bone CO2 stores were involved.

  13. Yeast respond to hypotonic shock with a calcium pulse

    NASA Technical Reports Server (NTRS)

    Batiza, A. F.; Schulz, T.; Masson, P. H.

    1996-01-01

    We have used the transgenic AEQUORIN calcium reporter system to monitor the cytosolic calcium ([Ca2+]cyt) response of Saccharomyces cerevisiae to hypotonic shock. Such a shock generates an almost immediate and transient rise in [Ca2+]cyt which is eliminated by gadolinium, a blocker of stretch-activated channels. In addition, this transient rise in [Ca2+]cyt is initially insensitive to 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), an extracellular calcium chelator. However, BAPTA abruptly attenuates the maintenance of that transient rise. These data show that hypotonic shock generates a stretch-activated channel-dependent calcium pulse in yeast. They also suggest that the immediate calcium influx is primarily generated from intracellular stores, and that a sustained increase in [Ca2+]cyt depends upon extracellular calcium.

  14. Calcium solubility of dental enamel following Er, Cr:YSGG laser irradiation

    NASA Astrophysics Data System (ADS)

    Apel, Christian; Graeber, Hans-Georg; Gutknecht, Norbert

    2000-03-01

    Ever since the laser was introduced in dental medicine, there has been a constant discussion about its use in caries prevention. Various studies have already illustrated the possible uses of CO2 and argon lasers in this field of dentistry. The aim of the present study was to examine the Er,Cr:YSGG laser with regard to potential in reducing the acid solubility of dental enamel. Thirty freshly extracted bovine incisor teeth were prepared for this purpose. The crowns of the teeth were covered with hard wax, leaving a standardized test area free. The test specimens were then divided into three groups. The test area was uniformly irradiated with 2.7 J/cm2 in the first test group and 6.5 J/cm2 in the second test group. The third test group was left untreated (control group). Demineralization of the teeth was performed over a period of 24 hours in acetate buffer solution (0.1 mol/l) with a pH value of 4.5 and a temperature of 37 degrees Celsius. The calcium content of the solution was subsequently determined by flame photometry. The results confirm a significantly lower calcium content in the test group exposed to radiation of 6.5 J/cm2 (p less than 0.025). Dental enamel seems to have increased acid resistance following irradiation with the Er,Cr:YSGG laser.

  15. Ethylenediaminetetraacetic acid in endodontics

    PubMed Central

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

  16. Role of supplemental calcium in the recurrence of colorectal adenomas: a metaanalysis of randomized controlled trials.

    PubMed

    Shaukat, Aasma; Scouras, Nicole; Schünemann, Holger J

    2005-02-01

    Colorectal adenomas are neoplastic growths that are important targets for chemoprevention. Dietary calcium is thought to play an important role in chemoprevention. However, the role of calcium supplementation for preventing recurrence of adenomas is controversial. We performed a systematic review and meta-analysis to study the role of calcium supplementation in preventing recurrence of adenomas. We searched electronic bibliographic databases (Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, CINAHL, EMBASE, and MEDLINE) and contacted authors to identify potentially eligible studies. We identified three trials including 1,485 subjects with previously removed adenomas who were randomized to calcium versus placebo supplementation. The study endpoint was recurrence of adenomas at the end of 3-4 yr in 1,279 patients who completed the trials. We found that the recurrence of adenomas was significantly lower in subjects randomized to calcium supplementation (RR: 0.80, CI: 0.68, 0.93; p-value = 0.004). This systematic review and meta-analysis suggest that calcium supplementation prevents recurrent colorectal adenomas.

  17. Calcium channel antagonists in the treatment of hypertension.

    PubMed

    Weber, Michael A

    2002-01-01

    Calcium channel antagonists are widely used antihypertensive agents. Their popularity among primary care physicians is not only due to their blood pressure-lowering effects, but also because they appear to be effective regardless of the age or ethnic background of the patients. The first available calcium channel antagonists utilized immediate-release formulations which, although effective in patients with angina pectoris, were not approved by the US FDA for use in hypertension. When long-acting once-daily formulations were approved in this indication, the short-acting preparations--which had by then become generic and inexpensive--retained some residual unapproved use for hypertension. An observational case-controlled trial, based on such usage, noted that these agents were associated with a greater risk of myocardial infarctions than conventional agents such as diuretics and beta-adrenoceptor antagonists. Further case-controlled trials showed, in fact, that the dangers of calcium channel antagonists were confined to the short-acting agents and that approved long-acting agents were at least as well tolerated and effective as other antihypertensive drugs. Cardiovascular outcomes during treatment with calcium channel antagonists have been examined in randomized, controlled trials. Compared with placebo, the calcium channel antagonists clearly prevented strokes and other cardiovascular events and reduced mortality. The effects of these agents on survival and clinical outcomes were similar to those with other antihypertensive drugs. There is a slight tendency for the calcium channel antagonists to be more effective than other drug types in preventing stroke, but slightly less effective in preventing coronary events. These observations extend to high-risk patients with hypertension including those with diabetes mellitus. Even so, patients with evidence of nephropathy should not receive monotherapy with calcium channel antagonists. Such patients are optimally treated

  18. Salicylic acid and calcium-induced protection of wheat against salinity.

    PubMed

    Al-Whaibi, Mohamed H; Siddiqui, Manzer H; Basalah, Mohammed O

    2012-07-01

    Soil salinity is one of the important environmental factors that produce serious agricultural problems. The objective of the present study was to determine the interactive effect of salicylic acid (SA) and calcium (Ca) on plant growth, photosynthetic pigments, proline (Pro) concentration, carbonic anhydrase (CA) activity and activities of antioxidant enzymes of Triticum aestivum L. (cv. Samma) under salt stress. Application of 90 mM of NaCl reduced plant growth (plant height, fresh weight (FW) and dry weight (DW), chlorophyll (Chl) a, Chl b, CA activity) and enhanced malondialdehyde (MDA) and Pro concentration. However, the application of SA or Ca alone as well as in combination markedly improved plant growth, photosynthetic pigments, Pro concentration, CA activity and activities of antioxidant enzymes peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and ascorbate peroxidase (APX) under salt stress. It was, therefore, concluded that application of SA and Ca alone as well as in combination ameliorated the adverse effect of salinity, while combined application proved more effective to reduce the oxidative stress generated by NaCl through reduced MDA accumulation, Chl a/b ratio and Chls degradation and enhanced activities of antioxidant enzymes.

  19. [Folic acid: Primary prevention of neural tube defects. Literature Review].

    PubMed

    Llamas Centeno, M J; Miguélez Lago, C

    2016-03-01

    Neural tube defects (NTD) are the most common congenital malformations of the nervous system, they have a multifactorial etiology, are caused by exposure to chemical, physical or biological toxic agents, factors deficiency, diabetes, obesity, hyperthermia, genetic alterations and unknown causes. Some of these factors are associated with malnutrition by interfering with the folic acid metabolic pathway, the vitamin responsible for neural tube closure. Its deficit produce anomalies that can cause abortions, stillbirths or newborn serious injuries that cause disability, impaired quality of life and require expensive treatments to try to alleviate in some way the alterations produced in the embryo. Folic acid deficiency is considered the ultimate cause of the production of neural tube defects, it is clear the reduction in the incidence of Espina Bifida after administration of folic acid before conception, this leads us to want to further study the action of folic acid and its application in the primary prevention of neural tube defects. More than 40 countries have made the fortification of flour with folate, achieving encouraging data of decrease in the prevalence of neural tube defects. This paper attempts to make a literature review, which clarify the current situation and future of the prevention of neural tube defects.

  20. Development and characterization of an injectable cement of nano calcium-deficient hydroxyapatite/multi(amino acid) copolymer/calcium sulfate hemihydrate for bone repair

    PubMed Central

    Qi, Xiaotong; Li, Hong; Qiao, Bo; Li, Weichao; Hao, Xinyan; Wu, Jun; Su, Bao; Jiang, Dianming

    2013-01-01

    A novel injectable bone cement was developed by integration of nano calcium-deficient hydroxyapatite/multi(amino acid) copolymer (n-CDHA/MAC) and calcium sulfate hemihydrate (CSH; CaSO4 · 1/2H2O). The structure, setting time, and compressive strength of the cement were investigated. The results showed that the cement with a liquid to powder ratio of 0.8 mL/g exhibited good injectability and appropriate setting time and mechanical properties. In vitro cell studies indicated that MC3T3-E1 cells cultured on the n-CDHA/MAC/CSH composite spread well and showed a good proliferation state. The alkaline phosphatase activity of the MC3T3-E1 cells cultured on the n-CDHA/MAC/CSH composite was significantly higher than that of the cells on pure CSH at 4 and 7 days of culture. The n-CDHA/MAC/CSH cement was implanted into critical size defects of the femoral condyle in rabbits to evaluate its biocompatibility and osteogenesis in vivo. Radiological and histological results indicated that introduction of the n-CDHA/MAC into CSH enhanced new bone formation, and the n-CDHA/MAC/CSH cement exhibited good biocompatibility and degradability. In conclusion, the injectable n-CDHA/MAC/CSH composite cement has a significant clinical advantage over pure CSH cement, and may be a promising bone graft substitute for the treatment of bone defects. PMID:24293996

  1. Folic acid awareness among female college students: neural tube defects prevention.

    PubMed

    Kari, Jameela A; Bardisi, Ekhlas S; Baitalmal, Rabaa M; Ageely, Ghofran A

    2008-12-01

    To investigate the level of awareness among female college students on the importance of preconception folic acid supplementation in preventing neural tube defects (NTDs). We have also studied their response after educating them. This is a questionnaire-based study. Five hundreds questionnaires were distributed to the female students of the 3 colleges, namely, Humanities, Sciences, and Health in Jeddah, Kingdom of Saudi Arabia in April 2008. The questions included an enquiry on their knowledge regarding the importance of folic acid preconception, and if they will implement what they learned after listening to lectures, delivered by the 4th year medical students, who were trained and supervised by the faculty members of the King Abdul-Aziz University. Two hundred and seventeen questionnaires were filled, and returned (43.4%). Mean age +/- SD was 20.96 +/- 2.25 years. Almost 88% were not aware of the importance of folic acid in preventing NTDs. After listening to the lecture, 82.9% thought that they will surely use folic acid preconception, and 98.6% will relay the important message about the importance of folic acid to others. There is a need to increase the awareness of the importance of folic acid among females' childbearing age. Medical students' involvement in educating college students was an effective way to increase their awareness. Similar educating programs are required, in order to reduce the high incidence of NTDs.

  2. Calcium carbonate crystals promote calcium oxalate crystallization by heterogeneous or epitaxial nucleation: possible involvement in the control of urinary lithogenesis.

    PubMed

    Geider, S; Dussol, B; Nitsche, S; Veesler, S; Berthézène, P; Dupuy, P; Astier, J P; Boistelle, R; Berland, Y; Dagorn, J C; Verdier, J M

    1996-07-01

    A large proportion of urinary stones have calcium oxalate (CaOx) as the major mineral phase. In these stones, CaOx is generally associated with minor amounts of other calcium salts. Several reports showing the presence of calcium carbonate (CaCO3) and calcium phosphate in renal stones suggested that crystals of those salts might be present in the early steps of stone formation. Such crystals might therefore promote CaOx crystallization from supersaturated urine by providing an appropriate substrate for heterogeneous nucleation. That possibility was investigated by seeding a metastable solution of 45Ca oxalate with vaterite or calcite crystallites. Accretion of CaOx was monitored by 45Ca incorporation. We showed that (1) seeds of vaterite (the hexagonal polymorph of CaCO3) and calcite (the rhomboedric form) could initiate calcium oxalate crystal growth; (2) in the presence of lithostathine, an inhibitor of CaCO3 crystal growth, such accretion was not observed. In addition, scanning electron microscopy demonstrated that growth occurred by epitaxy onto calcite seeds whereas no special orientation was observed onto vaterite. It was concluded that calcium carbonate crystals promote crystallization of calcium oxalate and that inhibitors controlling calcium carbonate crystal formation in Henle's loop might play an important role in the prevention of calcium oxalate stone formation.

  3. Periconceptional folic acid prevents miscarriage in Irish families with neural tube defects.

    PubMed

    Byrne, J

    2011-03-01

    Miscarriages occur to excess in sibships with neural tube defects (NTDs) and among maternal versus paternal relatives in NTD families. Folic acid prevents most NTDs. Its potential to prevent miscarriages has been controversial. We evaluated the relationship of maternal line and periconceptional folic acid with miscarriage. First cousins in Irish families with NTDs were interviewed about pregnancy outcomes and the health of their offspring. Miscarriages were not more frequent among pregnancies of maternal versus paternal first cousins. Folic acid intake during early pregnancy significantly reduced the risk of miscarriage from 15.7 to 9.6%, for an adjusted odds ratio of 0.37 (95% confidence interval 0.19, 0.72, p = 0.005). Folic acid during pregnancy was associated with a reduction of approximately 60% in miscarriages. Miscarriages are common-one in every eight pregnancies in this study. If incorporated into pre-pregnancy counseling, these results could have significant public health impact.

  4. Calcium and bone health in children: a review.

    PubMed

    Stallings, V A

    1997-01-01

    The recent national survey shows that dietary calcium intake is variable in children and adolescents, with about half consuming less than the intake recommended by the Recommended Dietary Allowances or the National Institutes of Health Consensus Panel on Optimal Calcium Intake. Osteoporosis is a major disease in adults, resulting in 1.5 million fractures and over $10 billion in medical expenditures annually. Osteoporosis is of growing interest in the research, public health, and health consumer-lay communities and to the many primary care and specialty physicians and other health care professionals who work directly with patients with osteoporosis. Treatment of osteoporosis to prevent fracture is improving with newly introduced medications and approaches, but it is not as effective as needed. Effective prevention strategies are critical to decreasing the morbidity and mortality of the disease. Peak bone mass, obtained during childhood and adolescent growth, is one of the major determinants for the risk of developing osteoporosis and fracture. Genetic potential, gender, ethnic origins, nutritional factors such as calcium and vitamin D intake, growth patterns, and physical activity influence the accretion of bone mineral during childhood and determine the peak bone mass. Randomized, placebo-controlled intervention trials conducted in healthy children who are consuming amounts of dietary calcium in accordance with the US recommendations show that bone mass can be increased by calcium supplementation. Retrospective studies in adults suggest that childhood calcium intake is associated with risk of later osteoporosis and fracture. In addition, common childhood clinical conditions, such as low calcium intake related to lactose intolerance or the use of glucocorticoid medications for chronic illness, are risk factors for the development of osteoporosis in childhood, not just in adulthood. An approach for physicians and other pediatric care providers for screening children

  5. Calcium carbonate gallstones in children.

    PubMed

    Stringer, Mark D; Soloway, Roger D; Taylor, Donald R; Riyad, Kallingal; Toogood, Giles

    2007-10-01

    In the United States, cholesterol stones account for 70% to 95% of adult gallstones and black pigment stones for most of the remainder. Calcium carbonate stones are exceptionally rare. A previous analysis of a small number of pediatric gallstones from the north of England showed a remarkably high prevalence of calcium carbonate stones. The aims of this study were to analyze a much larger series of pediatric gallstones from our region and to compare their chemical composition with a series of adult gallstones from the same geographic area. A consecutive series of gallbladder stones from 63 children and 50 adults from the north of England were analyzed in detail using Fourier transform infrared microspectroscopy. Demographic and clinical data were collected on all patients. The relative proportions of each major stone component were assessed: cholesterol, protein and calcium salts of bilirubin, fatty acids, calcium carbonate, and hydroxyapatite. Thirty-nine (78%) adults had typical cholesterol stones, 7 (14%) had black pigment bilirubinate stones, and only 2 (4%) had calcium carbonate stones. In contrast, 30 (48%) children had black pigment stones, 13 (21%) had cholesterol stones, 15 (24%) had calcium carbonate stones, 3 (5%) had protein dominant stones, and 2 (3%) had brown pigment stones. In children, cholesterol stones were more likely in overweight adolescent girls with a family history of gallstones, whereas black pigment stones were equally common in boys and girls and associated with hemolysis, parenteral nutrition, and neonatal abdominal surgery. Calcium carbonate stones were more common in boys, and almost half had undergone neonatal abdominal surgery and/or required neonatal intensive care. The composition of pediatric gallstones differs significantly from that found in adults. In particular, one quarter of the children in this series had calcium carbonate stones, previously considered rare. Geographic differences are not the major reason for the high

  6. The Role of Poly(Aspartic Acid) in the Precipitation of Calcium Phosphate in Confinement

    PubMed Central

    Cantaert, Bram; Beniash, Elia

    2013-01-01

    Many questions remain regarding the formation of ultrathin hydroxapatite (HAP) crystals within the confines of collagen fibrils of bones. These structures form through the interplay of the collagen matrix and non-collagenous proteins, and in vitro mineralization studies employing poly(aspartic acid) (PAsp) as a mimic of the non-collagenous proteins have generated mineralized fibrils with structures comparable to their biogenic counterparts. In this article, we employ the nanoscale cylindrical pores perforating track-etch filtration membranes to investigate the role of PAsp in controlling the infiltration and crystallization of calcium phosphate (CaP) within confined volumes. Oriented polycrystalline HAP and non-oriented octacalcium phosphate (OCP) rods precipitated within the membrane pores via an amorphous calcium phosphate (ACP) precursor, where PAsp increased the proportion of OCP rods. Further, ACP crystallized faster within the membranes than in bulk solution when PAsp was present, suggesting that PAsp inhibits crystallization in solution, but promotes it when bound to a substrate. Finally, in contrast to the collagen system, PAsp reduced the yield of intra-membrane mineral and failed to enhance infiltration. This suggests that a specific interaction between the collagen matrix and ACP/PAsp precursor particles drives effective infiltration. Thus, while orientation of HAP crystals can be achieved by confinement alone, the chemistry of the collagen matrix is necessary for efficient mineralisation with CaP. PMID:24409343

  7. The Role of Poly(Aspartic Acid) in the Precipitation of Calcium Phosphate in Confinement.

    PubMed

    Cantaert, Bram; Beniash, Elia; Meldrum, Fiona C

    2013-12-28

    Many questions remain regarding the formation of ultrathin hydroxapatite (HAP) crystals within the confines of collagen fibrils of bones. These structures form through the interplay of the collagen matrix and non-collagenous proteins, and in vitro mineralization studies employing poly(aspartic acid) (PAsp) as a mimic of the non-collagenous proteins have generated mineralized fibrils with structures comparable to their biogenic counterparts. In this article, we employ the nanoscale cylindrical pores perforating track-etch filtration membranes to investigate the role of PAsp in controlling the infiltration and crystallization of calcium phosphate (CaP) within confined volumes. Oriented polycrystalline HAP and non-oriented octacalcium phosphate (OCP) rods precipitated within the membrane pores via an amorphous calcium phosphate (ACP) precursor, where PAsp increased the proportion of OCP rods. Further, ACP crystallized faster within the membranes than in bulk solution when PAsp was present, suggesting that PAsp inhibits crystallization in solution, but promotes it when bound to a substrate. Finally, in contrast to the collagen system, PAsp reduced the yield of intra-membrane mineral and failed to enhance infiltration. This suggests that a specific interaction between the collagen matrix and ACP/PAsp precursor particles drives effective infiltration. Thus, while orientation of HAP crystals can be achieved by confinement alone, the chemistry of the collagen matrix is necessary for efficient mineralisation with CaP.

  8. Increased serum nonesterified fatty acid and low ionised calcium concentrations are associated with post partum colic in mares.

    PubMed

    Holcombe, S J; Embertson, R M; Kurtz, K A; Roessner, H A; Wismer, S E; Geor, R J; Kaneene, J B

    2016-01-01

    Increased serum nonesterified fatty acids (NEFA) and decreased serum electrolytes are linked to abdomasal displacements in post partum dairy cattle. Post partum colic in mares may be associated with metabolic changes specific to pregnancy and the periparturient period. To determine if fluctuations in serum NEFA, ionised calcium (iCa) and magnesium (iMg) occurred in periparturient mares and if these alterations were associated with post partum colic. Longitudinal observational study. Mares from 3 farms in central Kentucky were enrolled. Blood samples were collected 14 days prior to the estimated foaling date, within 4 days post parturition, and 14 and 28 days after foaling for batch analysis of serum NEFA, iCa and iMg. Health information was provided by farm managers and veterinarians. Data were analysed using Kruskal-Wallis χ(2) statistic for nonparametric data and a matched case/control approach. Repeated measures logistic regression models were developed. Serum NEFAs were higher at 14-1 day before foaling (mean ± s.d., mmol/l), 0.28 ± 0.12, P = 0.04 and from foaling to 4 days after foaling, 0.29 ± 0.20 (P = 0.05) in mares that developed colic compared with those that did not colic, 0.19 ± 0.05 and 0.21 ± 0.14, respectively. Ionised calcium was lower at 15-28 days post foaling in mares that showed colic, 1.50 ± 0.17 compared to mares that did not colic, 1.60 ± 0.12, P = 0.02. Risk of colic in post partum mares increased 38% for each 0.1 mmol/l increase in serum NEFA (odds ratio = 1.38, 95% confidence interval 1.06-1.81, P = 0.02). Mares with post partum colic had significantly higher serum NEFA and lower iCa prior to the colic episode compared with mares that did not develop colic. Monitoring these metabolic alterations may lead to predictive and preventive colic strategies for post partum mares. © 2015 EVJ Ltd.

  9. Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality

    PubMed Central

    2011-01-01

    Background Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Methods Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Results Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological p

  10. Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality.

    PubMed

    Fenton, Tanis R; Tough, Suzanne C; Lyon, Andrew W; Eliasziw, Misha; Hanley, David A

    2011-04-30

    Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies

  11. Novel rechargeable calcium phosphate nanocomposite with antibacterial activity to suppress biofilm acids and dental caries.

    PubMed

    Al-Dulaijan, Yousif A; Cheng, Lei; Weir, Michael D; Melo, Mary Anne S; Liu, Huaibing; Oates, Thomas W; Wang, Lin; Xu, Hockin H K

    2018-05-01

    Rechargeable calcium phosphate (CaP) composites were developed recently. However, none of the rechargeable CaP composites was antibacterial. The objectives of this study were to develop the first rechargeable CaP composite that was antibacterial, and to investigate the effects of adding dimethylaminohexadecyl methacrylate (DMAHDM) into rechargeable CaP composite on ion rechargeability and re-release as well as biofilm properties. DMAHDM was synthesized via a Menschutkin reaction. Nanoparticles of amorphous calcium phosphate (NACP) were synthesized using a spray-drying technique. The resin contained ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM). Two composites were fabricated: rechargeable NACP composite, and rechargeable NACP-DMAHDM composite. Mechanical properties and ion release and recharge were measured. A dental plaque microcosm biofilm model using saliva was tested. Flexural strength and elastic modulus of rechargeable NACP and NACP-DMAHDM composites matched commercial control composite (p > 0.1). NACP-DMAHDM inhibited biofilm metabolic activity and lactic acid, and reduced biofilm colony-forming units (CFU) by 3-4 log. NACP and NACP-DMAHDM showed similar Ca and P ion recharge and re-release (p > 0.1). Therefore, adding DMAHDM did not compromise the ion rechargeability. One recharge yielded continuous release for 42 d. The release was maintained at the same level with increasing number of recharge cycles, indicating long-term ion release and remineralization capability. The first CaP rechargeable and antibacterial composite was developed. Adding DMAHDM into the rechargeable NACP composite did not adversely affect the Ca and P ion release and recharge, and the composite had much less biofilm growth and lactic acid production, with CFU reduction by 3-4 log. This novel CaP rechargeable composite with long-term remineralization and antibacterial properties is promising for tooth restorations to inhibit

  12. Structural and dynamical studies of acid-mediated conversion in amorphous-calcium-phosphate based dental composites

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.

    Our objective was to investigate the complex structural and dynamical conversion process of the amorphous-calcium-phosphate (ACP)-to-apatite transition in ACP based dental composite materials. Composite disks were prepared using zirconia hybridized ACP fillers (0.4 mass fraction) and photo-activated Bis-GMA/TEGDMA resin (0.6 mass fraction). We performed an investigation of the solution-mediated ACP-to-apatite conversion mechanism in controlled acidic aqueous environment with in situ ultra-small angle X-ray scattering based coherent X-ray photon correlation spectroscopy and ex situ X-ray diffraction, as well as other complementary techniques. We established that the ACP-to-apatite conversion in ACP composites is a two-step process, owing to the sensitivity to localmore » structural changes provided by coherent X-rays. Initially, ACP undergoes a local microstructural rearrangement without losing its amorphous character. We established the catalytic role of the acid and found the time scale of this rearrangement strongly depends on the pH of the solution, which agrees with previous findings about ACP without the polymer matrix being present. In the second step, ACP is converted to an apatitic form with the crystallinity of the formed crystallites being poor. Separately, we also confirmed that in the regular Zr-modified ACP the rate of ACP conversion to hydroxyapatite is slowed significantly compared to unmodified ACP, which is beneficial for targeted slow release of functional calcium and phosphate ions from dental composite materials. Significantly, for the first time, we were able to follow the complete solution-mediated transition process from ACP to apatite in this class of dental composites in a controlled aqueous environment. A two-step process, suggested previously, was conclusively identified.« less

  13. Structural and dynamical studies of acid-mediated conversion in amorphous-calcium-phosphate based dental composites

    DOE PAGES

    Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.; ...

    2014-07-28

    Our objective was to investigate the complex structural and dynamical conversion process of the amorphous-calcium-phosphate (ACP)-to-apatite transition in ACP based dental composite materials. Composite disks were prepared using zirconia hybridized ACP fillers (0.4 mass fraction) and photo-activated Bis-GMA/TEGDMA resin (0.6 mass fraction). We performed an investigation of the solution-mediated ACP-to-apatite conversion mechanism in controlled acidic aqueous environment with in situ ultra-small angle X-ray scattering based coherent X-ray photon correlation spectroscopy and ex situ X-ray diffraction, as well as other complementary techniques. We established that the ACP-to-apatite conversion in ACP composites is a two-step process, owing to the sensitivity to localmore » structural changes provided by coherent X-rays. Initially, ACP undergoes a local microstructural rearrangement without losing its amorphous character. We established the catalytic role of the acid and found the time scale of this rearrangement strongly depends on the pH of the solution, which agrees with previous findings about ACP without the polymer matrix being present. In the second step, ACP is converted to an apatitic form with the crystallinity of the formed crystallites being poor. Separately, we also confirmed that in the regular Zr-modified ACP the rate of ACP conversion to hydroxyapatite is slowed significantly compared to unmodified ACP, which is beneficial for targeted slow release of functional calcium and phosphate ions from dental composite materials. Significantly, for the first time, we were able to follow the complete solution-mediated transition process from ACP to apatite in this class of dental composites in a controlled aqueous environment. A two-step process, suggested previously, was conclusively identified.« less

  14. Structural and dynamical studies of acid-mediated conversion in amorphous-calcium-phosphate based dental composites

    PubMed Central

    Zhang, Fan; Allen, Andrew J.; Levine, Lyle E.; Vaudin, Mark D.; Skrtic, Drago; Antonucci, Joseph M.; Hoffman, Kathleen M.; Giuseppetti, Anthony A.; Ilavsky, Jan

    2014-01-01

    Objective To investigate the complex structural and dynamical conversion process of the amorphous-calcium-phosphate (ACP) -to-apatite transition in ACP based dental composite materials. Methods Composite disks were prepared using zirconia hybridized ACP fillers (0.4 mass fraction) and photo-activated Bis-GMA/TEGDMA resin (0.6 mass fraction). We performed an investigation of the solution-mediated ACP-to-apatite conversion mechanism in controlled acidic aqueous environment with in situ ultra-small angle X-ray scattering based coherent X-ray photon correlation spectroscopy and ex situ X-ray diffraction, as well as other complementary techniques. Results We established that the ACP-to-apatite conversion in ACP composites is a two-step process, owing to the sensitivity to local structural changes provided by coherent X-rays. Initially, ACP undergoes a local microstructural rearrangement without losing its amorphous character. We established the catalytic role of the acid and found the time scale of this rearrangement strongly depends on the pH of the solution, which agrees with previous findings about ACP without the polymer matrix being present. In the second step, ACP is converted to an apatitic form with the crystallinity of the formed crystallites being poor. Separately, we also confirmed that in the regular Zr-modified ACP the rate of ACP conversion to hydroxyapatite is slowed significantly compared to unmodified ACP, which is beneficial for targeted slow release of functional calcium and phosphate ions from dental composite materials. Significance For the first time, we were able to follow the complete solution-mediated transition process from ACP to apatite in this class of dental composites in a controlled aqueous environment. A two-step process, suggested previously, was conclusively identified. PMID:25082155

  15. Fourier transform Raman spectroscopy of synthetic and biological calcium phosphates.

    PubMed

    Sauer, G R; Zunic, W B; Durig, J R; Wuthier, R E

    1994-05-01

    Fourier-transform (FT) Raman spectroscopy was used to characterize the organic and mineral components of biological and synthetic calcium phosphate minerals. Raman spectroscopy provides information on biological minerals that is complimentary to more widely used infrared methodologies as some infrared-inactive vibrational modes are Raman-active. The application of FT-Raman technology has, for the first time, enabled the problems of high sample fluorescence and low signal-to-noise that are inherent in calcified tissues to be overcome. Raman spectra of calcium phosphates are dominated by a very strong band near 960 cm-1 that arises from the symmetric stretching mode (v1) of the phosphate group. Other Raman-active phosphate vibrational bands are seen at approximately 1075 (v3), 590 (v4), and 435 cm-1 (v2). Minerals containing acidic phosphate groups show additional vibrational modes. The different calcium phosphate mineral phases can be distinguished from one another by the relative positions and shapes of these bands in the Raman spectra. FT-Raman spectra of nascent, nonmineralized matrix vesicles (MV) show a distinct absence of the phosphate v1 band even though these structures are rich in calcium and phosphate. Similar results were seen with milk casein and synthetic Ca-phosphatidyl-serine-PO4 complexes. Hence, the phosphate and/or acidic phosphate ions in these noncrystalline biological calcium phosphates is in a molecular environment that differs from that in synthetic amorphous calcium phosphate. In MV, the first distinct mineral phase to form contained acidic phosphate bands similar to those seen in octacalcium phosphate. The mineral phase present in fully mineralized MV was much more apatitic, resembling that found in bones and teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Crystal structure of metagenomic β-xylosidase/ α-l-arabinofuranosidase activated by calcium.

    PubMed

    Matsuzawa, Tomohiko; Kaneko, Satoshi; Kishine, Naomi; Fujimoto, Zui; Yaoi, Katsuro

    2017-09-01

    The crystal structure of metagenomic β-xylosidase/α-l-arabinofuranosidase CoXyl43, activated by calcium ions, was determined in its apo and complexed forms with xylotriose or l-arabinose in the presence and absence of calcium. The presence of calcium ions dramatically increases the kcat of CoXyl43 for p-nitrophenyl β-d-xylopyranoside and reduces the Michaelis constant for p-nitrophenyl α-l-arabinofuranoside. CoXyl43 consists of a single catalytic domain comprised of a five-bladed β-propeller. In the presence of calcium, a single calcium ion was observed at the centre of this catalytic domain, behind the catalytic pocket. In the absence of calcium, the calcium ion was replaced with one sodium ion and one water molecule, and the positions of these cations were shifted by 1.3 Å. The histidine-319 side chain, which coordinates to the 2-hydroxyl oxygen atom of the bound xylose molecule in the catalytic pocket, also coordinates to the calcium ion, but not to the sodium ion. The calcium-dependent increase in activity appears to be caused by the structural change in the catalytic pocket induced by the tightly bound calcium ion and coordinating water molecules, and by the protonation state of glutamic acid-268, the catalytic acid of the enzyme. Our findings further elucidate the complex relationship between metal ions and glycosidases. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  17. [Prevention and regeneration of barrier disturbances in occupational dermatology].

    PubMed

    Schürer, Nanna Y; Schwanitz, Hans J

    2004-11-01

    Over the past 10 years primary, secondary and tertiary prevention of occupational skin disorders has been shown to be successful, documented with appropriate statistical methods. Interventional strategies are the main features of secondary and tertiary prevention, now well-established in occupational dermatology. Primary prevention is best accomplished by health education measures, both in the form on individual counseling and seminars. This overview reviews the scientific background of hand eczema with respect to barrier damage and repair and then considers the options for individualized and focused prevention. Special anatomical features of the interdigital space and palms, as well as functional disorders, such as palmar hyperhidrosis, are discussed. The importance of barrier regeneration is considered in light of the role of an acid pH, the epidermal calcium gradient and aspects of percutaneous absorption. The effects of anti-oxidants are considered, and new bioengineering methods which rely on physiologic measuring techniques are reviewed.

  18. Prevention of space flight induced soft tissue calcification and disuse osteoporosis

    NASA Technical Reports Server (NTRS)

    Schneider, Victor S.; Leblanc, Adrian; Huntoon, Carolyn L.

    1990-01-01

    Medical complications such as renal stone formation, increased uric acid output, and disuse osteoporosis are discussed. A series of experiments was conducted in order to study and eventually reduce these flight hazards. Attempts to prevent the negative calcium balance and loss of calcaneal density during prolonged bed rest had only a limited success. Of the five biochemical regiments tested, only diphosphonate applied in a high dose had a positive effect in elliminating mineral losses. It is found that clodronate can prevent disuse osteoporosis and that fluoride can enhance bone formation. It is concluded that exercises, combined with pharmaceutical agents, are beneficial during long-duration space missions.

  19. [The antioxidant prevention of disorders in calcium ion metabolism under the action of glutamate on the synaptosomes of the rat cerebral cortex].

    PubMed

    Avrova, N F; Shestak, K I; Zakharova, I O; Sokolova, T V; Tiurina, Iu Iu; Tiurin, V A

    1999-04-01

    An increase of intracellular calcium ion concentration and of the 45Ca2+ entry, a decrease in Na+,K(+)-ATPase activity, and activation of Na+/Ca2+ exchange were shown to be initiated by glutamate in the rat brain cortex synaptosomes. These effects could be prevented with antagonists and blocking agents of the NMDA receptors. Pre-incubation of the synaptosomes with alpha-tocopherol, superoxide dismutase, and ganglioside GM1 was shown to normalise [45Ca2+], the rate of 45Ca2+ entry, and the activity of Na+,K(+)-ATPase in the synaptosomes. The data obtained suggest that calcium ions entering the brain cortex neurones via the NMDA receptors in presence of excessive glutamate, trigger activation of free radical reactions damaging the neurones in ischemia, cerebral lesions, and other pathological conditions.

  20. Effect of calcium soaps of fatty acids and administration of somatotropin on milk production, preovulatory follicular development, and plasma and follicular fluid lipid composition in high yielding dairy cows.

    PubMed

    Moallem, U; Folman, Y; Bor, A; Arav, A; Sklan, D

    1999-11-01

    The effect of fat and bovine somatotropin (bST) on preovulatory follicular hormones and lipids was evaluated by feeding cows for 150 d from parturition a control diet, a control diet plus 0.55 kg/d of calcium soaps of fatty acids, or a control diet with 500 mg of bST injected every 14 d. Fourteen days after a synchronized or natural estrus, cows were injected with a PGF2 alpha analogue; 48 h later, follicular fluid from all ovarian follicles > 8 mm was aspirated. Cows fed fat or injected with bST produced more milk and milk solids than did control cows, and cows on the bST treatment lost more body condition after calving than did cows on the other treatments. Both treatments changed the proportion of estradiol-active follicles (> 400 ng of estradiol/ml of follicular fluid) and the correlation between follicular fluid estradiol concentration and the total number large follicles per cow. In follicles aspirated between 60 and 90 DIM the percentage of estradiol-active follicles was 67, 40, and 0 for cows on the control, calcium soaps of fatty acids, and bST treatments, respectively. After 90 DIM, no differences existed between treatments in the percentage of estradiol-active follicles. Estradiol concentration in follicular fluid was correlated with DIM at follicle aspiration (r = 0.51). The proportion of oleic acid in free fatty acids in plasma at 50 DIM was lower in control cows and was lower in follicular fluid of estradiol-active follicles. Both calcium soaps of fatty acids and bST had a considerable effect on follicular development and activity and the composition of fatty acids in follicles.

  1. Effects of ascorbate on leucocytes: Part II. Effects of ascorbic acid and calcium and sodium ascorbate on neutrophil phagocytosis and post-phagocytic metabolic activity.

    PubMed

    Anderson, R

    1979-09-01

    The effects of ascorbic acid and calcium and sodium ascorbate at a concentration range of 10(-6)M - 10(-1)M on polymorphonuclear leucocyte (PMN) phagocytosis of Candida albicans and post-phagocytic nitroblue tetrazolium (NBT) reduction, hexose monophosphate shunt (HMS) activity and myeloperoxidase-mediated iodination of ingested protein were investigated. Phagocytosis of C. albicans was unaffected by ascorbate concentrations of 10(-6)M - 10(-2)M; however, progressive inhibition was observed at concentrations of 10(-2)M upwards. Enhancement of resting and stimulated HMS activity and NBT reduction was evident at ascorbate concentrations of 10(-5) M - 10(-2)M. The stimulations of HMS activity and NBT reduction was independent of myeloperoxidase iodination of ingested protein and this latter function was strongly inhibited by ascorbate. Concentrations of ascorbic acid and calcium and sodium ascorbate which caused inhibition of phagocytosis and HMS activity were the same as those which mediated stimulation of cell motility, indicating that independent cellular mechanisms may govern motility and phagocytosis.

  2. Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests

    NASA Astrophysics Data System (ADS)

    Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.

    2015-12-01

    Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric

  3. Mimicking the biomolecular control of calcium oxalate monohydrate crystal growth: effect of contiguous glutamic acids.

    PubMed

    Grohe, Bernd; Hug, Susanna; Langdon, Aaron; Jalkanen, Jari; Rogers, Kem A; Goldberg, Harvey A; Karttunen, Mikko; Hunter, Graeme K

    2012-08-21

    Scanning confocal interference microscopy (SCIM) and molecular dynamics (MD) simulations were used to investigate the adsorption of the synthetic polypeptide poly(l-glutamic acid) (poly-glu) to calcium oxalate monohydrate (COM) crystals and its effect on COM formation. At low concentrations (1 μg/mL), poly-glu inhibits growth most effectively in ⟨001⟩ directions, indicating strong interactions of the polypeptide with {121} crystal faces. Growth in <010> directions was inhibited only marginally by 1 μg/mL poly-glu, while growth in <100> directions did not appear to be affected. This suggests that, at low concentrations, poly-glu inhibits lattice-ion addition to the faces of COM in the order {121} > {010} ≥ {100}. At high concentrations (6 μg/mL), poly-glu resulted in the formation of dumbbell-shaped crystals featuring concave troughs on the {100} faces. The effects on crystal growth indicate that, at high concentrations, poly-glu interacts with the faces of COM in the order {100} > {121} > {010}. This mirrors MD simulations, which predicted that poly-glu will adsorb to a {100} terrace plane (most calcium-rich) in preference to a {121} (oblique) riser plane but will adsorb to {121} riser plane in preference to an {010} terrace plane (least calcium-rich). The effects of different poly-glu concentration on COM growth (1-6 μg/mL) may be due to variations between the faces in terms of growth mechanism and/or (nano)roughness, which can affect surface energy. In addition, 1 μg/mL might not be adequate to reach the critical concentration for poly-glu to significantly pin step movement on {100} and {010} faces. Understanding the mechanisms involved in these processes is essential for the development of agents to reduce recurrence of kidney stone disease.

  4. The potential benefits of dietary and/or supplemental calcium and vitamin D.

    PubMed

    Moyad, Mark A

    2003-01-01

    Osteoporosis is a significant problem in women and men. In addition, as osteoporosis has garnered more attention there should be more attention than ever placed on the potential benefits of calcium and vitamin D. Clinicians need to inform patients that there are numerous healthy dietary sources of calcium and vitamin D. Calcium and vitamin D supplements seem to act synergistically to reduce fracture risk in men and women; therefore, they need to be taken together to impact fracture risk. In addition, almost every randomized trial of an effective osteoporosis drug therapy has utilized calcium and vitamin D to enhance the efficacy of the drug itself. Several forms of calcium supplements are commercially available today and clinicians need to understand the similarities and differences between them. Calcium and vitamin D in moderation also have a good safety profile and may actually have benefits far beyond osteoporosis therapy. For example, calcium may increase high-density lipoprotein (HDL), prevent colon polyps, reduce blood pressure, reduce kidney stone recurrence, and may promote weight loss. Vitamin D may reduce the risk of some cancers, provide an enhanced response to some chemotherapeutic agents, prevent type I diabetes, and may reduce tooth loss along with calcium. Clinicians need to encourage individuals to receive the recommended daily allowance of these two agents because they seem to have an impact on numerous health conditions besides osteoporosis.

  5. Aortic valve calcium independently predicts coronary and cardiovascular events in a primary prevention population.

    PubMed

    Owens, David S; Budoff, Matthew J; Katz, Ronit; Takasu, Junichiro; Shavelle, David M; Carr, J Jeffrey; Heckbert, Susan R; Otto, Catherine M; Probstfield, Jeffrey L; Kronmal, Richard A; O'Brien, Kevin D

    2012-06-01

    This study sought to test whether aortic valve calcium (AVC) is independently associated with coronary and cardiovascular events in a primary-prevention population. Aortic sclerosis is associated with increased cardiovascular morbidity and mortality among the elderly, but the mechanisms underlying this association remain controversial. Also, it is unknown whether this association extends to younger individuals. We performed a prospective analysis of 6,685 participants in MESA (Multi-Ethnic Study of Atherosclerosis). All subjects, ages 45 to 84 years and free of clinical cardiovascular disease at baseline, underwent computed tomography for AVC and coronary artery calcium scoring. The primary, pre-specified combined endpoint of cardiovascular events included myocardial infarctions, fatal and nonfatal strokes, resuscitated cardiac arrest, and cardiovascular death, whereas a secondary combined endpoint of coronary events excluded strokes. The association between AVC and clinical events was assessed using Cox proportional hazards regression with incremental adjustments for demographics, cardiovascular risk factors, inflammatory biomarkers, and subclinical coronary atherosclerosis. Over a median follow-up of 5.8 years (interquartile range: 5.6 to 5.9 years), adjusting for demographics and cardiovascular risk factors, subjects with AVC (n = 894, 13.4%) had higher risks of cardiovascular (hazard ratio [HR]: 1.50; 95% confidence interval [CI]: 1.10 to 2.03) and coronary (HR: 1.72; 95% CI: 1.19 to 2.49) events compared with those without AVC. Adjustments for inflammatory biomarkers did not alter these associations, but adjustment for coronary artery calcium substantially attenuated both cardiovascular (HR: 1.32; 95% CI: 0.98 to 1.78) and coronary (HR: 1.41; 95% CI: 0.98 to 2.02) event risk. AVC remained predictive of cardiovascular mortality even after full adjustment (HR: 2.51; 95% CI: 1.22 to 5.21). In this MESA cohort, free of clinical cardiovascular disease, AVC predicts

  6. Hypochlorhydria-induced calcium malabsorption does not affect fracture healing but increases post-traumatic bone loss in the intact skeleton.

    PubMed

    Haffner-Luntzer, Melanie; Heilmann, Aline; Heidler, Verena; Liedert, Astrid; Schinke, Thorsten; Amling, Michael; Yorgan, Timur Alexander; Vom Scheidt, Annika; Ignatius, Anita

    2016-11-01

    Efficient calcium absorption is essential for skeletal health. Patients with impaired gastric acidification display low bone mass and increased fracture risk because calcium absorption is dependent on gastric pH. We investigated fracture healing and post-traumatic bone turnover in mice deficient in Cckbr, encoding a gastrin receptor that affects acid secretion by parietal cells. Cckbr-/- mice display hypochlorhydria, calcium malabsorption, and osteopenia. Cckbr-/- and wildtype (WT) mice received a femur osteotomy and were fed either a standard or calcium-enriched diet. Healed and intact bones were assessed by biomechanical testing, histomorphometry, micro-computed tomography, and quantitative backscattering. Parathyroid hormone (PTH) serum levels were determined by enzyme-linked immunosorbent assay. Fracture healing was unaffected in Cckbr-/- mice. However, Cckbr-/- mice displayed increased calcium mobilization from the intact skeleton during bone healing, confirmed by significantly elevated PTH levels and osteoclast numbers compared to WT mice. Calcium supplementation significantly reduced secondary hyperparathyroidism and bone resorption in the intact skeleton in both genotypes, but more efficiently in WT mice. Furthermore, calcium administration improved bone healing in WT mice, indicated by significantly increased mechanical properties and bone mineral density of the fracture callus, whereas it had no significant effect in Cckbr-/- mice. Therefore, under conditions of hypochlorhydria-induced calcium malabsorption, calcium, which is essential for callus mineralization, appears to be increasingly mobilized from the intact skeleton in favor of fracture healing. Calcium supplementation during fracture healing prevented systemic calcium mobilization, thereby maintaining bone mass and improving fracture healing in healthy individuals whereas the effect was limited by gastric hypochlorhydria. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J

  7. Efficacy of homocysteine lowering therapy with folic acid in stroke prevention: a meta-analysis

    PubMed Central

    Lee, Meng; Hong, Keun-Sik; Chang, Shen-Chih; Saver, Jeffrey L.

    2010-01-01

    Background and Purpose Although lower serum homocysteine concentration is associated with a reduced risk of stroke in epidemiologic studies, randomized controlled trials (RCTs) have yielded mixed findings regarding the effect of therapeutic homocysteine lowering on stroke prevention. We performed a meta-analysis of RCTs to assess the efficacy of folic acid supplementation in the prevention of stroke. Methods Salient trials were identified by formal literature search. Relative risk (RR) with 95% confidence interval (CI) was used as a measure of the association between folic acid supplementation and risk of stroke, pooling data across trials using a fixed-effects model. Results The search identified 13 RCTs of folic acid therapy to reduce homocysteine, enrolling 39,005 participants, in which stroke was reported as an outcome measure. Across all trials, folic acid supplementation was associated with a trend toward mild benefit that did not reach statistical significance in reducing the risk of stroke (RR 0.93, 95% CI 0.85-1.03; p=0.16). The RR for non-secondary prevention trials was 0.89 (95% CI 0.79-0.99; p=0.03). In stratified analyses, a greater beneficial effect was seen in the trials testing combination therapy of folic acid plus vitamins B6 and B12 (RR 0.83, 0.71-0.97; p=0.02) and in the trials which disproportionately enrolled male patients (men/women > 2, RR 0.84, 0.74-0.94; p=0.003). Conclusions Folic acid supplementation did not demonstrate a major effect in averting stroke. However, potential mild benefits in primary stroke prevention, especially when folate is combined with B vitamins and in male patients, merit further investigation. PMID:20413740

  8. Substantially Stabilized Superacid Incorporated SBA-15 with Calcium Bridging for Selective Esterification of Glycerol

    NASA Astrophysics Data System (ADS)

    Hoo, P. Y.; Abdullah, A. Z.; Shuit, S. H.; Teoh, Y. P.; Ng, Q. H.; Kunasundari, B.

    2018-03-01

    The exploitation of the super acidity of heteropolyacids incorporated heterogeneous catalysts was only feasible if the heterogeneity of these catalysts was assured. To maintain the catalyst heterogeneity in polar medium, a novel two-step modification method was proposed to synthesize the highly active, yet stable heterogeneous catalyst, catered for selective esterification of monoglyceride. The surficial, structural and acidity properties of the modified catalysts were investigated via crucial characterization methods (N2 BET, HRTEM, and FTIR). The collective evidences verified the predicted formation of calcium oxides (CaO) on the mesopores surfaces of the SBA-15 support after the first modification, and the successful subsequent 12-tungstophosphoric acid (HPW) functionalization. The superior stability of the synthesized catalysts (10wt%-HPW/CaSBA-15) was demonstrated (negligible change in both conversion – 75% and yield – 70%), without the need for catalyst regeneration. Such result was attributed to the strong interaction between HPW and SBA-15 via calcium bridging. Being alkaline in nature, calcium oxides in the inner pores readily reacted with highly acidic HPW introduced in the subsequent wetness incipient step, forming insoluble HPW acid sites on inner pore walls of SBA-15 via the calcium bridging. This modification deemed promising and other alkaline metals should be explored in the future.

  9. Calcium Intake in Elderly Australian Women Is Inadequate

    PubMed Central

    Meng, Xingqiong; Kerr, Deborah A.; Zhu, Kun; Devine, Amanda; Solah, Vicky; Binns, Colin W.; Prince, Richard L.

    2010-01-01

    The role of calcium in the prevention of bone loss in later life has been well established but little data exist on the adequacy of calcium intakes in elderly Australian women. The aim of this study was to compare the dietary intake including calcium of elderly Australian women with the Australian dietary recommendation, and to investigate the prevalence of calcium supplement use in this population. Community-dwelling women aged 70–80 years were randomly recruited using the Electoral Roll for a 2-year protein intervention study in Western Australia. Dietary intake was assessed at baseline by a 3-day weighed food record and analysed for energy, calcium and other nutrients. A total of 218 women were included in the analysis. Mean energy intake was 7,140 ± 1,518 kJ/day and protein provided 19 ± 4% of energy. Mean dietary calcium intake was 852 ± 298 mg/day, which is below Australian recommendations. Less than one quarter of women reported taking calcium supplements and only 3% reported taking vitamin D supplements. Calcium supplements by average provided calcium 122 ± 427 mg/day and when this was taken into account, total calcium intake increased to 955 ± 504 mg/day, which remained 13% lower than the Estimated Average Requirement (EAR, 1,100 mg/day) for women of this age group. The women taking calcium supplements had a higher calcium intake (1501 ± 573 mg) compared with the women on diet alone (813 ± 347 mg). The results of this study indicate that the majority of elderly women were not meeting their calcium requirements from diet alone. In order to achieve the recommended dietary calcium intake, better strategies for promoting increased calcium, from both diet and calcium supplements appears to be needed. PMID:22254072

  10. Ascorbic acid prevents vascular dysfunction induced by oral glucose load in healthy subjects.

    PubMed

    De Marchi, Sergio; Prior, Manlio; Rigoni, Anna; Zecchetto, Sara; Rulfo, Fanny; Arosio, Enrico

    2012-01-01

    To examine the effects of oral glucose load on forearm circulatory regulation before and after ascorbic acid administration in healthy subjects. Microcirculation study with laser Doppler was performed at the hand in basal conditions, after ischemia and after acetylcholine and nitroprusside; strain gauge plethysmography was performed at basal and after ischemia. The tests were repeated in the same sequence 2 hour after oral administration of glucose (75 g). The subjects were randomised for administration of ascorbic acid (1 g bid) or placebo (sodium bicarbonate 1 g bid) for 10 days. After that, the tests were repeated before and after a new oral glucose load. Blood pressure and heart rate were monitored. Macrocirculatory flux, pressure values and heart rate were unvaried throughout the study. The glucose load caused a reduction in the hyperemic peak flow with laser Doppler and plethysmography; it reduced flux recovery time and hyperemic curve area after ischemia; acetylcholine elicited a minor increase in flux with laser Doppler. The response to nitroprusside was unvaried after glucose load as compared to basal conditions. Treatment with ascorbic acid prevented the decrease in hyperemia after glucose, detected with laser Doppler and plethysmography. Ascorbic acid prevented the decreased response to acetylcholine after glucose, the response to nitroprusside was unaffected by ascorbic acid. Results after placebo were unvaried. Oral glucose load impairs endothelium dependent dilation and hyperaemia at microcirculation, probably via oxidative stress; ascorbic acid can prevent it. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  11. Risk assessment and causal preventive measures.

    PubMed

    Lussi, Adrian; Hellwig, Elmar

    2014-01-01

    A prerequisite for preventive measures is to diagnose erosive tooth wear and to evaluate the different etiological factors in order to identify persons at risk. No diagnostic device is available for the assessment of erosive defects. Thus, they can only be detected clinically. Consequently, erosion not diagnosed at an early stage may render timely preventive measures difficult. In order to assess the risk factors, patients should record their dietary intake for a distinct period of time. Then a dentist can determine the erosive potential of the diet. A table with common beverages and foodstuffs is presented for judging the erosive potential. Particularly, patients with more than 4 dietary acid intakes have a higher risk for erosion when other risk factors are present. Regurgitation of gastric acids is a further important risk factor for the development of erosion which has to be taken into account. Based on these analyses, an individually tailored preventive program may be suggested to the patients. It may comprise dietary advice, use of calcium-enriched beverages, optimization of prophylactic regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for nondestructive toothbrushing habits with an erosive-protecting toothpaste as well as rinsing solutions. Since erosion and abrasion often occur simultaneously, all of the causative components must be taken into consideration when planning preventive strategies but only those important and feasible for an individual should be communicated to the patient. © 2014 S. Karger AG, Basel.

  12. Use of the Coronary Artery Calcium Score in Discussion of Initiation of Statin Therapy in Primary Prevention.

    PubMed

    Michos, Erin D; Blaha, Michael J; Blumenthal, Roger S

    2017-12-01

    Clinical guidelines for instituting pharmacotherapy for the primary prevention of atherosclerotic cardiovascular disease (ASCVD), specifically lipid management and aspirin, have long been based on absolute risk. However, lipid management in the current era remains challenging to both patients and clinicians in the setting of somewhat discordant recommendations from various organizations. All guidelines endorse the use of statins for primary prevention for those at sufficient absolute risk, and treatment recommendations are generally "risk-based" rather than exclusively targeting specific low-density lipoprotein cholesterol levels. Nonetheless, guidelines differ in relation to the risk threshold for initiation and the intensity of statin treatment. The key concept of the clinician-patient risk discussion introduced in the 2013 American College of Cardiology/American Heart Association cholesterol guidelines is a process that addresses the potential for ASCVD risk reduction with statin treatment, potential for adverse treatment effects, patient preferences, encouragement of heart-healthy lifestyle, and management of other risk factors. However, operationalizing the clinician-patient risk discussion requires effective communication of the most accurate and personalized risk information. In this article, we review our treatment approach for the appropriate use of coronary artery calcium testing in the intermediate-risk patient to guide shared decision making. The decision to initiate or intensify statin therapy may be uncertain across a broad range of estimated 10-year ASCVD risk of 5% to 20%, and coronary artery calcium testing can reclassify risk upward or downward in approximately 50% of this group to inform the risk discussion. We conclude with 2 case-based examples of uncertain risk and uncertain statin therapeutic benefit to illustrate execution of the clinician-patient risk discussion. Copyright © 2017 Mayo Foundation for Medical Education and Research

  13. The role of polyelectrolytes in the stabilization of calcium phosphate nanoparticles for the production of biomimetic materials

    NASA Astrophysics Data System (ADS)

    Krogstad, Daniel; Wang, Dongbo; Lin-Gibson, Sheng

    2014-03-01

    The exceptional mechanical properties of bone are a result of the hierarchical assembly of hydroxyapatite and the bone matrix, which is primarily composed of collagen. However, it has been shown that without highly acidic, non-collagenous proteins (NCP), which comprise only a few percent of the total organic material, collagen cannot be mineralized correctly. Although the exact roles of these NCP are unknown, it is believed that they are responsible for the stabilization and transportation of the apatite precursor, amorphous calcium phosphate (ACP). In this work, polyaspartic acid was used as a synthetic analog for NCP and the structure and kinetics of calcium phosphate nanoparticle formation were determined at various concentrations using cryo-TEM and scattering. From this investigation, it was determined that the size and stability of the ACP nanoparticles could be directly controlled by the relative ion and polymer concentrations. Interestingly, at high polymer concentrations, the particles remained suspended in solution even after they transformed from ACP to apatite indicating that the polymers have a strong ability to prevent particle aggregation. Through these results, control over the particle size and stability has been increased which will help in the design and development of biomimetic materials.

  14. Crystallization of calcium oxalate dihydrate in a buffered calcium-containing glucose solution by irradiation with non-equilibrium atmospheric pressure plasma

    NASA Astrophysics Data System (ADS)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Mizuno, Masaaki; Ikehara, Yuzuru; Hori, Masaru

    2017-10-01

    Oxalate was synthesized in the glucose solution by irradiation with non-equilibrium atmospheric pressure plasma (NEAPP), in which the NEAPP plume contacted the solution surface, via the generation of several intermediate organic products such as gluconic acid. A thermodynamically unstable phase of calcium oxalate dihydrate crystallized rapidly during incubation of a NEAPP-irradiated glucose solution that contained calcium ions and was buffered at neutral pH. Longer irradiation times increased the growth rate and the number of seed crystals.

  15. Extracellular protons enable activation of the calcium-dependent chloride channel TMEM16A.

    PubMed

    Cruz-Rangel, Silvia; De Jesús-Pérez, José J; Aréchiga-Figueroa, Iván A; Rodríguez-Menchaca, Aldo A; Pérez-Cornejo, Patricia; Hartzell, H Criss; Arreola, Jorge

    2017-03-01

    The calcium-activated chloride channel TMEM16A provides a pathway for chloride ion movements that are key in preventing polyspermy, allowing fluid secretion, controlling blood pressure, and enabling gastrointestinal activity. TMEM16A is opened by voltage-dependent calcium binding and regulated by permeant anions and intracellular protons. Here we show that a low proton concentration reduces TMEM16A activity while maximum activation is obtained when the external proton concentration is high. In addition, protonation conditions determine the open probability of TMEM16A without changing its calcium sensitivity. External glutamic acid 623 (E623) is key for TMEM16A's ability to respond to external protons. At physiological pH, E623 is un-protonated and TMEM16A is activated when intracellular calcium increases; however, under acidic conditions E623 is partially protonated and works synergistically with intracellular calcium to activate the channel. These findings are critical for understanding physiological and pathological processes that involve changes in pH and chloride flux via TMEM16A. Transmembrane protein 16A (TMEM16A), also known as ANO1, the pore-forming subunit of a Ca 2+ -dependent Cl - channel (CaCC), is activated by direct, voltage-dependent, binding of intracellular Ca 2+ . Endogenous CaCCs are regulated by extracellular protons; however, the molecular basis of such regulation remains unidentified. Here, we evaluated the effects of different extracellular proton concentrations ([H + ] o ) on mouse TMEM16A expressed in HEK-293 cells using whole-cell and inside-out patch-clamp recordings. We found that increasing the [H + ] o from 10 -10 to 10 -5.5  m caused a progressive increase in the chloride current (I Cl ) that is described by titration of a protonatable site with pK = 7.3. Protons regulate TMEM16A in a voltage-independent manner, regardless of channel state (open or closed), and without altering its apparent Ca 2+ sensitivity. Noise analysis showed

  16. Prevention of acetic acid-induced colitis by desferrithiocin analogs in a rat model.

    PubMed

    Bergeron, Raymond J; Wiegand, Jan; Weimar, William R; Nguyen, John Nhut; Sninsky, Charles A

    2003-02-01

    Iron contributes significantly to the formation of reactive oxygen species via the Fenton reaction. Therefore, we assessed whether a series of desferrithiocin analogs, both carboxylic acids and hydroxamates, could (1) either promote or diminish the iron-mediated oxidation of ascorbate, (2) quench a model radical species, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), and (3) when applied topically, prevent acetic acid-induced colitis in rats. Surprisingly, most of the desferrithiocin analogs inhibited the Fenton reaction to an approximately equivalent degree; however, substantial differences were observed in the capacity of the analogs to scavenge the model radical cation. Four carboxylic acid desferrithiocin analogs and their respective N-methylhydroxamates were tested along with desferrioxamine and Rowasa, a currently accepted topical therapeutic agent for inflammatory bowel disease (IBD), in a rodent model of acetic acid-induced colitis. The colonic damage was quantitated by two independent measurements. Although neither radical scavenging nor prevention of Fenton chemistry was a definitive predictor of in vivo efficacy, the overall trend is that desferrithiocin analogs substituted with an N-methylhydroxamate in the place of the carboxylic acid are both better free radical scavengers and more active against acetic acid-induced colitis. These results represent an intriguing alternative avenue to the development of improved IBD therapeutic agents.

  17. Hydrocarbon-soluble calcium hydride: a "worker-bee" in calcium chemistry.

    PubMed

    Spielmann, Jan; Harder, Sjoerd

    2007-01-01

    The reactivity of the hydrocarbon-soluble calcium hydride complex [{CaH(dipp-nacnac)(thf)}(2)] (1; dipp-nacnac=CH{(CMe)(2,6-iPr(2)C(6)H(3)N)}(2)) with a large variety of substrates has been investigated. Addition of 1 to C=O and C=N functionalities gave easy access to calcium alkoxide and amide complexes. Similarly, reduction of the C[triple chemical bond]N bond in a cyanide or an isocyanide resulted in the first calcium aldimide complexes [Ca{N=C(H)R}(dipp-nacnac)] and [Ca{C(H)=NR}(dipp-nacnac)], respectively. Complexation of 1 with borane or alane Lewis acids gave the borates and alanates as contact ion pairs. In reaction with epoxides, nucleophilic ring-opening is observed as the major reaction. The high reactivity of hydrocarbon-soluble 1 with most functional groups contrasts strongly with that of insoluble CaH(2), which is essentially inert and is used as a common drying agent. Crystal structures of the following products are presented: [{Ca{OC(H)Ph(2)}(dipp-nacnac)}(2)], [{Ca{N=C(H)Ph}(dipp-nacnac)}(2)], [{Ca{C(H)=NC(Me)(2)CH(2)C(Me)(3)}(dipp-nacnac)}(2)], [{Ca{C(H)=NCy}(dipp-nacnac)}(2)], [Ca(dipp-nacnac)(thf)](+)[H(2)BC(8)H(14)](-) and [{Ca(OCy)(dipp-nacnac)}(2)]. The generally smooth and clean conversions of 1 with a variety of substrates and the stability of most intermediates against ligand exchange make 1 a valuable key precursor in the syntheses of a wide variety of beta-diketiminate calcium complexes.

  18. Decreased water flowing from a forest amended with calcium silicate

    Treesearch

    Mark B. Green; Amey S. Bailey; Scott W. Bailey; John J. Battles; John L. Campbell; Charles T. Driscoll; Timothy J. Fahey; Lucie C. Lepine; Gene E. Likens; Scott V. Ollinger; Paul G. Schaberg

    2013-01-01

    Acid deposition during the 20th century caused widespread depletion of available soil calcium (Ca) throughout much of the industrialized world. To better understand how forest ecosystems respond to changes in a component of acidification stress, an 11.8-ha watershed was amended with wollastonite, a calcium silicate mineral, to restore available soil Ca to preindustrial...

  19. Orthodontic cement with protein-repellent and antibacterial properties and the release of calcium and phosphate ions.

    PubMed

    Zhang, Ning; Weir, Michael D; Chen, Chen; Melo, Mary A S; Bai, Yuxing; Xu, Hockin H K

    2016-07-01

    White spot lesions often occur in orthodontic treatments. The objective of this study was to develop a novel resin-modified glass ionomer cement (RMGI) as an orthodontic cement with protein-repellent, antibacterial and remineralization capabilities. Protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC), antibacterial dimethylaminohexadecyl methacrylate (DMAHDM), nanoparticles of silver (NAg), and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into a RMGI. Enamel shear bond strength (SBS) was determined. Calcium (Ca) and phosphate (P) ion releases were measured. Protein adsorption onto specimens was determined by a micro bicinchoninic acid method. A dental plaque microcosm biofilm model was tested. Increasing the NACP filler level increased the Ca and P ion release. Decreasing the solution pH increased the ion release. Incorporating MPC into RMGI reduced protein adsorption, which was an order of magnitude less than that of commercial controls. Adding DMAHDM and NAg into RMGI yielded a strong antibacterial function, greatly reducing biofilm viability and acid production. Biofilm CFU counts on the multifunctional orthodontic cement were 3 orders of magnitude less than that of commercial control (p<0.05). These benefits were achieved without compromising the enamel shear bond strength (p>0.1). A novel multifunctional orthodontic cement was developed with strong antibacterial and protein-repellent capabilities for preventing enamel demineralization. The new cement is promising to prevent white spot lesions in orthodontic treatments. The method of incorporating four bioactive agents may have wide applicability to the development of other bioactive dental materials to inhibit caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 21 CFR 172.350 - Fumaric acid and salts of fumaric acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Fumaric acid and salts of fumaric acid. 172.350... HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.350 Fumaric acid and salts of fumaric acid. Fumaric acid and its calcium, ferrous, magnesium, potassium, and sodium salts may be safely used...

  1. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    NASA Technical Reports Server (NTRS)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  2. The use of antioxidants to prevent glutamate-induced derangement of calcium ion metabolism in rat cerebral cortex synaptosomes.

    PubMed

    Avrova, N F; Shestak, K I; Zakharova, I O; Sokolova, T V; Tyurina, Y Y; Tyurin, V A

    2000-01-01

    Glutamate is shown to induce increases in intracellular Ca2+ concentrations ([Ca2+]i), increases in 45Ca2+ influx, decreases in the activity of Na+,K+-ATPase activity, and activation of the Na+/Ca2+ exchanger in rat cerebral cortex synaptosomes. NMDA receptor antagonists virtually prevented these effects. Preincubation of synaptosomes with alpha-tocopherol, superoxide dismutase, and ganglioside GM1 normalized [Ca2+]i, 45Ca2+ influx, and Na+,K+-ATPase activity in rat cerebral cortex synaptosomes exposed to glutamate. Glutamate and GM1 activated the Na+/K+ exchanger, and their effects were additive. Calcium ions entering cerebral cortex nerve cells via NMDA receptors during exposure to high glutamate concentrations appeared to be only the trigger for the processes activating free-radical reactions. Activation of these reactions led to increases in Ca2+ influx into cells, decreases in Na+,K+-ATPase activity, and significant increases in [Ca2+]i, though this could be prevented by antioxidants and gangliosides.

  3. Spatially and temporally controlled biomineralization is facilitated by interaction between self-assembled dentin matrix protein 1 and calcium phosphate nuclei in solution.

    PubMed

    He, Gen; Gajjeraman, Sivakumar; Schultz, David; Cookson, David; Qin, Chunlin; Butler, William T; Hao, Jianjun; George, Anne

    2005-12-13

    Bone and dentin biomineralization are well-regulated processes mediated by extracellular matrix proteins. It is widely believed that specific matrix proteins in these tissues modulate nucleation of apatite nanoparticles and their growth into micrometer-sized crystals via molecular recognition at the protein-mineral interface. However, this assumption has been supported only circumstantially, and the exact mechanism remains unknown. Dentin matrix protein 1 (DMP1) is an acidic matrix protein, present in the mineralized matrix of bone and dentin. In this study, we have demonstrated using synchrotron small-angle X-ray scattering that DMP1 in solution can undergo oligomerization and temporarily stabilize the newly formed calcium phosphate nanoparticle precursors by sequestering them and preventing their further aggregation and precipitation. The solution structure represents the first low-resolution structural information for DMP1. Atomic force microscopy and transmission electron microscopy studies further confirmed that the nascent calcium phosphate nuclei formed in solution were assembled into ordered protein-mineral complexes with the aid of oligomerized DMP1, recombinant and native. This study reveals a novel mechanism by which DMP1 might facilitate initiation of mineral nucleation at specific sites during bone and dentin mineralization and prevent spontaneous calcium phosphate precipitation in areas in which mineralization is not desirable.

  4. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Krogstad, Daniel V.; Wang, Dongbo; Lin-Gibson, Sheng

    Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transformmore » infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.« less

  5. Serotonin and calcium homeostasis during the transition period.

    PubMed

    Weaver, S R; Laporta, J; Moore, S A E; Hernandez, L L

    2016-07-01

    The transition from pregnancy to lactation puts significant, sudden demands on maternal energy and calcium reserves. Although most mammals are able to effectively manage these metabolic adaptations, the lactating dairy cow is acutely susceptible to transition-related disorders because of the high amounts of milk being produced. Hypocalcemia is a common metabolic disorder that occurs at the onset of lactation. Hypocalcemia is also known to result in poor animal welfare conditions. In addition, cows that develop hypocalcemia are more susceptible to a host of other negative health outcomes. Different feeding tactics, including manipulating the dietary cation-anion difference and administering low-calcium diets, are commonly used preventative strategies. Despite these interventions, the incidence of hypocalcemia in the subclinical form is still as high as 25% to 30% in the United States dairy cow population, with a 5% to 10% incidence of clinical hypocalcemia. In addition, although there are various effective treatments in place, they are administered only after the cow has become noticeably ill, at which point there is already significant metabolic damage. This emphasizes the need for developing alternative prevention strategies, with the monoamine serotonin implicated as a potential therapeutic target. Our research in rodents has shown that serotonin is critical for the induction of mammary parathyroid hormone-related protein, which is necessary for the mobilization of bone tissue and subsequent restoration of maternal calcium stores during lactation. We have shown that circulating serotonin concentrations are positively correlated with serum total calcium on the first day of lactation in dairy cattle. Administration of serotonin's immediate precursor through feeding, injection, or infusion to various mammalian species has been shown to increase circulating serotonin concentrations, with positive effects on other components of maternal metabolism. Most recently

  6. Prevention of bone mineral changes induced by bed rest: Modification by static compression simulating weight bearing, combined supplementation of oral calcium and phosphate, calcitonin injections, oscillating compression, the oral diophosphonatedisodium etidronate, and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Schneider, V. S.; Hulley, S. B.; Donaldson, C. L.; Vogel, J. M.; Rosen, S. N.; Hantman, D. A.; Lockwood, D. R.; Seid, D.; Hyatt, K. H.; Jacobson, L. B.

    1974-01-01

    The phenomenon of calcium loss during bed rest was found to be analogous to the loss of bone material which occurs in the hypogravic environment of space flight. Ways of preventing this occurrence are investigated. A group of healthy adult males underwent 24-30 weeks of continuous bed rest. Some of them were given an exercise program designed to resemble normal ambulatory activity; another subgroup was fed supplemental potassium phosphate. The results from a 12-week period of treatment were compared with those untreated bed rest periods. The potassium phosphate supplements prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. The exercise program did not diminish the negative calcium balance. Neither treatment affected the heavy loss of mineral from the calcaneus. Several additional studies are developed to examine the problem further.

  7. Five year study of etidronate and/or calcium as prevention and treatment for osteoporosis and fractures in patients with asthma receiving long term oral and/or inhaled glucocorticoids.

    PubMed

    Campbell, I A; Douglas, J G; Francis, R M; Prescott, R J; Reid, D M

    2004-09-01

    Glucocorticoids are associated with a reduction in bone density and an increased risk of fracture. Concurrent treatment with bisphosphonates reduces bone loss and may prevent fractures. A randomised study was performed to determine whether treatment with cyclical etidronate and/or calcium for 5 years prevents fractures or reverses/reduces bone loss in patients receiving glucocorticoid treatment for asthma. A multicentre, randomised, parallel group comparison of etidronate alone, calcium alone, etidronate + calcium, and no treatment, with stratification according to level of glucocorticoid exposure was carried out in 39 chest clinics in the UK. Three hundred and forty nine postmenopausal female and male outpatients with asthma aged 50-70 years were randomised. The main outcome measures were fractures and changes in bone mineral density (BMD). Overall, 8% of the patients experienced symptomatic fractures and 17.5% developed either a symptomatic fracture and/or a semiquantitative vertebral fracture by the end of 5 years There were no significant differences between the four treatment groups. Comparing etidronate with no etidronate, the rates of new fractures were not significantly different for symptomatic fractures (OR 1.07 (95% CI 0.46 to 2.47)) or for any fractures (OR 0.82 (95% CI 0.45 to 1.47)). For the comparison of calcium with no calcium the corresponding ORs were 1.43 (95% CI 0.62 to 3.33) and 0.91 (95% CI 0.50 to 1.63). In post hoc analysis the effect of etidronate was greater in women than in men (interaction p value 0.02) with the fracture incidence roughly halved (OR 0.39, 95% CI 0.14 to 0.99). Etidronate increased BMD at the lumbar spine by 4.1% (p = 0.001) while calcium had no significant effect. At the proximal femur the effects of treatment were not significant (relative increases etidronate 1.6%; calcium 1.1%). The rate of new fractures in patients with fractures at entry (23.7%) was higher than in those without fractures at entry (14.3%): OR 1

  8. Effectiveness of the addition of alkaline materials at surface coal mines in preventing or abating acid mine drainage--Part 2. Mine site case studies

    USGS Publications Warehouse

    Brady, Keith; Smith, Michael W.; Beam, Richard L.; Cravotta,, Charles A.

    1990-01-01

    The effectiveness of preventing or ameliorating acid mine drainage (AMD) through the application of alkaline additives is evaluated for eight surface coal mines in Pennsylvania. Many of the mine sites had overburden characteristics that made prediction of post‐mining water quality uncertain. Alkaline materials were applied at rates ranging from 42 to greater than 1,000 tons as calcium carbonate per acre. In addition, two sites that were mined and reclaimed without alkaline additives are included for comparative purposes. Overburden sulfur concentration and "neutralization potential" (NP) data for multiple strata at each mine site were used to compute the cumulative, mass‐weighted "maximum potential acidity" (MPA) and "net neutralization potential" (NNP = NP ‐ MPA) by using three different calculation methods. Post‐reclamation water‐quality data were used to compute the net alkalinity (= alkalinity ‐ acidity). The most conservative determination of NNP, whereby MPA is calculated by multiplying the total sulfur concentration, in weight percent, by 62.5 instead of 31.25, yielded the best agreement with net alkalinity (patching signs on NNP and net alkalinity). The error in prediction using each method was that the reclaimed overburden was computed to be alkaline overall (NNP > 0), but the post‐reclamation water was acid (net alkalinity < 0). In general, alkaline addition rates were probably insufficient to neutralize, or too late to prevent, acid production in the mine spoil. At six of the seven mine sites that had overburden with insufficient NP relative to MPA (NNP < 0), the addition of alkaline materials failed to create alkaline mine drainage; AMD was formed or persisted. A control site which also had insufficient alkaline material, but did not incorporate alkaline additives, generated severe AMD. Two sites that had substantial, natural alkaline overburden produced alkaline drainage. Although the addition rates appear to be inadequate, other factors

  9. Efficient calcium lactate production by fermentation coupled with crystallization-based in situ product removal.

    PubMed

    Xu, Ke; Xu, Ping

    2014-07-01

    Lactic acid is a platform chemical with various industrial applications, and its derivative, calcium lactate, is an important food additive. Fermentation coupled with in situ product removal (ISPR) can provide more outputs with high productivity. The method used in this study was based on calcium lactate crystallization. Three cycles of crystallization were performed during the fermentation course using a Bacillus coagulans strain H-1. As compared to fed-batch fermentation, this method showed 1.7 times higher average productivity considering seed culture, with 74.4% more L-lactic acid produced in the fermentation with ISPR. Thus, fermentation coupled with crystallization-based ISPR may be a biotechnological alternative that provides an efficient system for production of calcium lactate or lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Calcium bioavailability and kinetics of calcium ascorbate and calcium acetate in rats.

    PubMed

    Cai, Jianwei; Zhang, Qinmin; Wastney, Meryl E; Weaver, Connie M

    2004-01-01

    The objective was to investigate the bioavailability and mechanism of calcium absorption of calcium ascorbate (ASC) and calcium acetate (AC). A series of studies was performed in adult Sprague-Dawley male rats. In the first study, each group of rats (n = 10/group) was assigned to one of the five test meals labeled with (45)Ca: (i) 25 mg calcium as heated ASC or (ii) unheated ASC, (iii) 25 mg calcium as unheated AC, (iv) 3.6 mg Ca as unheated ASC, or (v) unheated AC. Femur uptake indicated better calcium bioavailability from ASC than AC at both calcium loads. A 5-min heat treatment partly reduced bioavailability of ASC. Kinetic studies were performed to further investigate the mechanism of superior calcium bioavailability from ASC. Two groups of rats (n = 10/group) received oral doses of 25 mg Ca as ASC or AC. Each dose contained 20 micro Ci (45)Ca. Two additional groups of rats (n = 10/group) received an intravenous injection (iv) of 10 micro Ci (45)Ca after receiving an unlabeled oral dose of 25 mg calcium as ASC or AC. Sequential blood samples were collected over 48 hrs. Urine and fecal samples were collected every 12 hrs for 48 hrs and were analyzed for total calcium and (45)Ca content. Total calcium and (45)Ca from serum, urine, and feces were fitted by a compartment kinetics model with saturable and nonsaturable absorption pathways by WinSAAM (Windows-based Simulation Analysis and Modeling). The difference in calcium bioavailability between the two salts was due to differences in saturable rather than passive intestinal absorption and not to endogenous secretion or calcium deposition rate. The higher bioavailability of calcium ascorbate was due to a longer transit time in the small intestine compared with ASC.

  11. Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation.

    PubMed

    Afdhal, N H; Ostrow, J D; Koehler, R; Niu, N; Groen, A K; Veis, A; Nunes, D P; Offner, G D

    1995-11-01

    Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4 precipitation were studied. Binding of CBP to GBM was assessed by inhibition of the fluorescence of the complex of GBM with bis-1,8-anilinonaphthalene sulfonic acid (bis-ANS). The effects of the proteins on precipitation of CaHPO4 were assessed by nephelometry and gravimetry. Precipitates were analyzed for calcium, phosphate, and protein. CBP and bis-ANS competitively displaced each other from 30 binding sites on mucin, with a 1:1 stoichiometry and similar affinity. The rate of precipitation of CaHPO4 was retarded by mucin and CBP. Precipitate mass was unaffected by GBM alone but decreased with the addition of CBP. Complexing CBP with GBM abolished or moderated this latter effect, altered precipitate morphology, and changed the stoichiometric ratios of Ca to PO4 in the precipitates from 1:1 to 3:2. Mucin and CBP were incorporated into the precipitates. These studies suggest that the formation of calcium-containing gallstones is a biomineralization process regulated by both GBM and CBP.

  12. A study of calcium intake and sources of calcium in adolescent boys and girls from two socioeconomic strata, in Pune, India.

    PubMed

    Sanwalka, Neha J; Khadilkar, Anuradha V; Mughal, M Zulf; Sayyad, Mehmood G; Khadilkar, Vaman V; Shirole, Shilpa C; Divate, Uma P; Bhandari, Dhanshari R

    2010-01-01

    Adequate intake of calcium is important for skeletal growth. Low calcium intake during childhood and adolescence may lead to decreased bone mass accrual thereby increasing the risk of osteoporotic fractures. Our aim was to study dietary calcium intake and sources of calcium in adolescents from lower and upper economic strata in Pune, India. We hypothesized that children from lower economic strata would have lower intakes of calcium, which would predominantly be derived from non-dairy sources. Two hundred male and female adolescents, from lower and upper economic stratum were studied. Semiquantitative food frequency questionnaire was used to evaluate intakes of calcium, phosphorus, oxalic acid, phytin, energy and protein. The median calcium intake was significantly different in all four groups, with maximum intake in the upper economic strata boys (893 mg, 689-1295) and lowest intake in lower economic strata girls (506 mg, 380-674). The median calcium intake in lower economic strata boys was 767 mg (585-1043) and that in upper economic strata girls was 764 mg (541-959). The main source of calcium was dairy products in upper economic strata adolescents while it was dark green leafy vegetables in lower economic strata adolescents. The median calcium intake was much lower in lower economic strata than in the upper economic strata both in boys and girls. Girls from both groups had less access to dairy products as compared to boys. Measures need to be taken to rectify low calcium intake in lower economic strata adolescents and to address gender inequality in distribution of dairy products in India.

  13. Controlled environment life support system: Calcium-related leaf injuries on plants

    NASA Technical Reports Server (NTRS)

    Tibbitts, T. W.

    1986-01-01

    Calcium related injuries to plants grown in controlled environments under conditions which maximize plant growth rates are described. Procedures to encourage movement of calcium into developing leaves of lettuce plants were investigated. The time course and pattern of calcium accumulation was determined to develop effective control procedures for this injury, termed tipburn. Procedures investigated were: (1) increasing the relative humidity to saturation during the dark period and altering root temperatures, (2) maximizing water stress during light and minimizing water stress during dark periods, (3) shortening the light-dark cycle lengths in combination with elevated moisture levels during the dark cycles, (4) reducing nutrient concentrations and (5) vibrating the plants. Saturated humidities at night increased the rate of growth and the large fluctuation in plant water potential encouraged calcium movement to the young leaves and delayed tipburn. Root temperature regulation between 15 and 26 C was not effective in preventing tipburn. Attempts to modulate water stress produced little variation, but no difference in tipburn development. Variations in light-dark cycle lengths also had no effect on calcium concentrations within developing leaves and no variation in tipburn development. Low concentrations of nutrient solution delayed tipburn, presumably because of greater calcium transport in the low concentration plants. Shaking of the plants did not prevent tipburn, but did delay it slightly.

  14. Efficacy of Mixtures of Magnesium, Citrate and Phytate as Calcium Oxalate Crystallization Inhibitors in Urine.

    PubMed

    Grases, Felix; Rodriguez, Adrian; Costa-Bauza, Antonia

    2015-09-01

    The main aim of the current study was to evaluate the effectiveness of mixtures of magnesium, citrate and phytate as calcium oxalate crystallization inhibitors. A turbidimetric assay in synthetic urine was performed to obtain induction times for calcium oxalate crystallization in the absence and presence of different mixtures of inhibitors. The morphology of calcium oxalate crystals in the absence or presence of inhibitors and mixtures of the inhibitors was evaluated in 2 crystallization experiments at low and high calcium oxalate supersaturation. The crystals formed were examined using scanning electron microscopy. Examination of crystallization induction times revealed clear inhibitory effects of magnesium, citrate and phytate on calcium oxalate crystallization, supporting usefulness in the treatment and prevention of calcium oxalate nephrolithiasis. Significant synergistic effects between magnesium and phytate were observed. Scanning electron microscopy images revealed that phytate is a powerful crystal growth inhibitor of calcium oxalate, totally preventing the formation of trihydrate and monohydrate. In addition to crystallization inhibition capacity, citrate and magnesium avoided calcium oxalate crystallization by decreasing its supersaturation. The synergistic effect between magnesium and phytate on calcium oxalate crystallization suggests that a combination of these 2 compounds may be highly useful as antilithiasis therapy. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  15. The calcium content of human erythrocytes

    PubMed Central

    Harrison, D. G.; Long, C.

    1968-01-01

    1. The calcium content of human erythrocytes, after removal of the buffy coat and washing free from plasma with isotonic sodium chloride, has been determined by atomic absorption spectrophotometry. The mean value found for normal subjects was 0·634 μg/ml. of packed erythrocytes (0·0158 μg-atom/ml.). The corresponding values for magnesium and zinc were 79·7 and 20·1 μg/ml., respectively. 2. The calcium is considered to be mostly and perhaps exclusively located in the erythrocyte membrane, since, after osmotic haemolysis, the same amount was found in the ghost cells as was present in the erythrocytes from which they were prepared. By contrast, magnesium and zinc, which are essentially intracellular, were lost to the extent of about 96 and 92%, respectively. 3. About 90% of the calcium was removed from erythrocytes by washing with isotonic sodium chloride containing 5 mM ethylenediaminetetraacetate (EDTA), or other complexing agents of high stability constant for calcium. A small fraction of the magnesium but none of the zinc was removed by this treatment. 4. Other complexing agents of lower stability constant removed somewhat less calcium from the erythrocytes. Citrate was totally ineffective. 5. The buffy coat had a high calcium content, but this could not be removed by washing with EDTA. 6. Calcium was also determined in trichloroacetic acid extracts of ghost cells after ashing and treatment with bis-(o-hydroxyphenylimino)-ethane and measuring the red complex spectrophotometrically. The values obtained confirmed the atomic absorption measurements. PMID:4972779

  16. Phosphorylation of serine residues is fundamental for the calcium-binding ability of Orchestin, a soluble matrix protein from crustacean calcium storage structures.

    PubMed

    Hecker, Arnaud; Testenière, Olivier; Marin, Frédéric; Luquet, Gilles

    2003-01-30

    Orchestia cavimana is a terrestrial crustacean, which cyclically stores calcium in diverticula of the midgut, in the form of calcified amorphous concretions. These concretions are associated with a proteinaceous matrix, the main constituent of the soluble matrix is Orchestin, an acidic calcium-binding protein [Testenière et al., Biochem. J. 361 (2002) 327-335]. In the present paper, we clearly demonstrate that Orchestin is phosphorylated on serine and tyrosine residues, but that calcium binding only occurs via the phosphoserine residues. To our knowledge, this is the first example of an invertebrate mineralization for which a post-translational modification is clearly related to an important function of a calcifying protein.

  17. Proteomic Analysis of Calcium Effects on Soybean Root Tip under Flooding and Drought Stresses.

    PubMed

    Wang, Xin; Komatsu, Setsuko

    2017-08-01

    Flooding and drought are disadvantageous environmental conditions that induce cytosolic calcium in soybean. To explore the effects of flooding- and drought-induced increases in calcium, a gel-free/label-free proteomic analysis was performed. Cytosolic calcium was decreased by blocking calcium channels in the endoplasmic reticulum (ER) and plasma membrane under both stresses. Calnexin, protein disulfide isomerase, heat shock proteins and thioredoxin were predominantly affected as the ER proteins in response to calcium, and ER-associated degradation-related proteins of HCP-like superfamily protein were up-regulated under stress exposure and then down-regulated. Glycolysis, fermentation, the tricarboxylic acid cycle and amino acid metabolism were mainly induced as the types of cellular metabolism in response to calcium under both stresses. Pyruvate decarboxylase was increased and decreased under flooding and drought, respectively, and was further decreased by the reduction of cytosolic calcium; however, it was recovered by exogenous calcium under both stresses. Furthermore, pyruvate decarboxylase activity was increased under flooding, but decreased under drought. These results suggest that calcium is involved in protein folding in the ER, and ER-associated degradation might alleviate ER stress during the early stage of both stresses. Furthermore, calcium appears to modify energy metabolism, and pyruvate decarboxylase may be a key enzyme in this process under flooding and drought. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Targeting arachidonic acid pathway by natural products for cancer prevention and therapy.

    PubMed

    Yarla, Nagendra Sastry; Bishayee, Anupam; Sethi, Gautam; Reddanna, Pallu; Kalle, Arunasree M; Dhananjaya, Bhadrapura Lakkappa; Dowluru, Kaladhar S V G K; Chintala, Ramakrishna; Duddukuri, Govinda Rao

    2016-10-01

    Arachidonic acid (AA) pathway, a metabolic process, plays a key role in carcinogenesis. Hence, AA pathway metabolic enzymes phospholipase A 2 s (PLA 2 s), cyclooxygenases (COXs) and lipoxygenases (LOXs) and their metabolic products, such as prostaglandins and leukotrienes, have been considered novel preventive and therapeutic targets in cancer. Bioactive natural products are a good source for development of novel cancer preventive and therapeutic drugs, which have been widely used in clinical practice due to their safety profiles. AA pathway inhibitory natural products have been developed as chemopreventive and therapeutic agents against several cancers. Curcumin, resveratrol, apigenin, anthocyans, berberine, ellagic acid, eugenol, fisetin, ursolic acid, [6]-gingerol, guggulsteone, lycopene and genistein are well known cancer chemopreventive agents which act by targeting multiple pathways, including COX-2. Nordihydroguaiaretic acid and baicalein can be chemopreventive molecules against various cancers by inhibiting LOXs. Several PLA 2 s inhibitory natural products have been identified with chemopreventive and therapeutic potentials against various cancers. In this review, we critically discuss the possible utility of natural products as preventive and therapeutic agents against various oncologic diseases, including prostate, pancreatic, lung, skin, gastric, oral, blood, head and neck, colorectal, liver, cervical and breast cancers, by targeting AA pathway. Further, the current status of clinical studies evaluating AA pathway inhibitory natural products in cancer is reviewed. In addition, various emerging issues, including bioavailability, toxicity and explorability of combination therapy, for the development of AA pathway inhibitory natural products as chemopreventive and therapeutic agents against human malignancy are also discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Preventive treatment of calcium oxalate crystal deposition with immortal flowers.

    PubMed

    Orhan, Nilüfer; Onaran, Metin; Şen, İlker; Işık Gönül, İpek; Aslan, Mustafa

    2015-04-02

    A number of medicinal plants are used for their diuretic, urolithiatic and anti-inflammatory effects on urinary system problems in Turkey and the most common traditional remedy for kidney stones is the tea of immortal flowers. The aim of this study is to evaluate the preventive effect of infusions prepared from capitulums of Helichrysum graveolens (M.Bieb.) Sweet (HG) and Helichrysum stoechas ssp. barellieri (Ten.) Nyman (HS) on formation of kidney stones. Sodium oxalate (Ox-70mg/kg intraperitoneally) was used to induce kidney stones on Wistar albino rats. At the same time, two different doses of the plant extracts (HG: 62.5 and 125mg/kg; HS: 78 and 156mg/kg) were dissolved in the drinking water and administered to animals for 5 days. Potassium citrate was used as positive control in the experiments. During the experiment, water intake, urine volume and body weights of the animals were recorded. At the end of the experiments, liver, kidney and body weights of the animals were determined; biochemical analysis were conducted on urine, blood and plasma samples. Histopathological changes in kidney tissues were examined and statistical analysis were evaluated. HS extract showed the highest preventive effect at 156mg/kg dose (stone formation score: 1.16), whereas a number of kidney stones were maximum in sodium oxalate group (stone formation score: 2.66). Helichrysum extracts decreased urine oxalate and uric acid levels and increased citrate levels significantly. In addition, Helichrysum extracts regulated the negative changes in biochemical and hematological parameters occurred after Ox injection. We conclude that Helichrysum extracts could reduce the formation and growth of kidney stones in Ox-induced urolithiasis and can be beneficial for patients with recurrent stones. In addition, this is the first study on the preventive effect of immortal flowers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. A human intermediate conductance calcium-activated potassium channel.

    PubMed

    Ishii, T M; Silvia, C; Hirschberg, B; Bond, C T; Adelman, J P; Maylie, J

    1997-10-14

    An intermediate conductance calcium-activated potassium channel, hIK1, was cloned from human pancreas. The predicted amino acid sequence is related to, but distinct from, the small conductance calcium-activated potassium channel subfamily, which is approximately 50% conserved. hIK1 mRNA was detected in peripheral tissues but not in brain. Expression of hIK1 in Xenopus oocytes gave rise to inwardly rectifying potassium currents, which were activated by submicromolar concentrations of intracellular calcium (K0.5 = 0.3 microM). Although the K0.5 for calcium was similar to that of small conductance calcium-activated potassium channels, the slope factor derived from the Hill equation was significantly reduced (1.7 vs. 3. 5). Single-channel current amplitudes reflected the macroscopic inward rectification and revealed a conductance level of 39 pS in the inward direction. hIK1 currents were reversibly blocked by charybdotoxin (Ki = 2.5 nM) and clotrimazole (Ki = 24.8 nM) but were minimally affected by apamin (100 nM), iberiotoxin (50 nM), or ketoconazole (10 microM). These biophysical and pharmacological properties are consistent with native intermediate conductance calcium-activated potassium channels, including the erythrocyte Gardos channel.

  1. Calcium regulates FGF-23 expression in bone.

    PubMed

    David, Valentin; Dai, Bing; Martin, Aline; Huang, Jinsong; Han, Xiaobin; Quarles, L Darryl

    2013-12-01

    Calcium has recently been shown to regulate fibroblast growth factor 23 (FGF-23), a bone-derived phosphate and vitamin D-regulating hormone. To better understand the regulation of FGF-23 by calcium, phosphorus, 1,25 dihydroxyvitamin D3 [1,25(OH)2D], and PTH, we examined FGF-23 expression under basal conditions and in response to PTH, doxercalciferol, or high-calcium diet treatment in Gcm2(-/-) and Cyp27b1(-/-) mutant mice. Gcm2(-/-) mice exhibited low serum PTH and 1,25(OH)2D concentrations, hypocalcemia, and hyperphosphatemia, whereas Cyp27b1(-/-) mice had high PTH, undetectable 1,25(OH)2D, hypocalcemia, and hypophosphatemia. Serum FGF-23 levels were decreased in both mutant models. Doxercalciferol administration increased serum FGF-23 levels in both mutant models. PTH administration to Gcm2(-/-) mice also increased serum FGF-23 levels, in association with an increase in both 1,25(OH)2D and calcium concentrations. Multiple regression analysis of pooled data indicated that changes in FGF-23 were positively correlated with serum calcium and 1,25(OH)2D but not related to changes in serum phosphate concentrations. A high-calcium diet also increased serum FGF-23 concentrations in Cyp27b1(-/-) mice in the absence of 1,25(OH)2D and in Gcm2(-/-) mice with low PTH. The addition of calcium to the culture media also stimulated FGF-23 message expression in MC3T3-E1 osteoblasts. In addition, FGF-23 promoter activity in cultured osteoblasts was inhibited by the L-calcium-channel inhibitor nifedipine and stimulated by calcium ionophores. The effects of chronic low calcium to prevent 1,25(OH)2D and PTH stimulation of FGF-23 in these mutant mouse models suggest that suppression of FGF-23 plays an important physiological adaptive response to hypocalcemia.

  2. Nitric oxide augments voltage-activated calcium currents of crustacea (Idotea baltica) skeletal muscle.

    PubMed

    Erxleben, C; Hermann, A

    2001-03-16

    Invertebrate skeletal muscle contraction is regulated by calcium influx through voltage-dependent calcium channels in the sarcolemmal membrane. In present study we investigated the effects of nitric oxide (NO) donors on calcium currents of single skeletal muscle fibres from the marine isopod, Idotea baltica, using two-electrode voltage clamp recording techniques. The NO donors, S-nitrosocysteine, S-nitroso-N-acetyl-penicillamine or hydroxylamine reversibly increased calcium inward currents in a time dependent manner. The increase of the current was prevented by methylene blue. Our experiments suggest that NO increases calcium inward currents. NO, by acting on calcium ion channels in the sarcolemmal membrane, therefore, may directly be involved in the modulation of muscle contraction.

  3. The activity of ferulic and gallic acids in biofilm prevention and control of pathogenic bacteria.

    PubMed

    Borges, Anabela; Saavedra, Maria J; Simões, Manuel

    2012-01-01

    The activity of two phenolic acids, gallic acid (GA) and ferulic acid (FA) at 1000 μg ml(-1), was evaluated on the prevention and control of biofilms formed by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. In addition, the effect of the two phenolic acids was tested on planktonic cell susceptibility, bacterial motility and adhesion. Biofilm prevention and control were tested using a microtiter plate assay and the effect of the phenolic acids was assessed on biofilm mass (crystal violet staining) and on the quantification of metabolic activity (alamar blue assay). The minimum bactericidal concentration for P. aeruginosa was 500 μg ml(-1) (for both phenolic acids), whilst for E. coli it was 2500 μg ml(-1) (FA) and 5000 μg ml(-1) (GA), for L. monocytogenes it was >5000 μg ml(-1) (for both phenolic acids), and for S. aureus it was 5000 μg ml(-1) (FA) and >5000 μg ml(-1) (GA). GA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. FA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. Colony spreading of S. aureus was completely inhibited by FA. The interference of GA and FA with bacterial adhesion was evaluated by the determination of the free energy of adhesion. Adhesion was less favorable when the bacteria were exposed to GA (P. aeruginosa, S. aureus and L. monocytogenes) and FA (P. aeruginosa and S. aureus). Both phenolics had preventive action on biofilm formation and showed a higher potential to reduce the mass of biofilms formed by the Gram-negative bacteria. GA and FA promoted reductions in biofilm activity >70% for all the biofilms tested. The two phenolic acids demonstrated the potential to inhibit bacterial motility and to prevent and control biofilms of four important human pathogenic bacteria. This study also emphasizes the potential of phytochemicals as an emergent source of biofilm

  4. Cardiac Myocyte-specific Knock-out of Calcium-independent Phospholipase A2γ (iPLA2γ) Decreases Oxidized Fatty Acids during Ischemia/Reperfusion and Reduces Infarct Size *

    PubMed Central

    Moon, Sung Ho; Mancuso, David J.; Sims, Harold F.; Liu, Xinping; Nguyen, Annie L.; Yang, Kui; Guan, Shaoping; Dilthey, Beverly Gibson; Jenkins, Christopher M.; Weinheimer, Carla J.; Kovacs, Attila; Abendschein, Dana; Gross, Richard W.

    2016-01-01

    Calcium-independent phospholipase A2γ (iPLA2γ) is a mitochondrial enzyme that produces lipid second messengers that facilitate opening of the mitochondrial permeability transition pore (mPTP) and contribute to the production of oxidized fatty acids in myocardium. To specifically identify the roles of iPLA2γ in cardiac myocytes, we generated cardiac myocyte-specific iPLA2γ knock-out (CMiPLA2γKO) mice by removing the exon encoding the active site serine (Ser-477). Hearts of CMiPLA2γKO mice exhibited normal hemodynamic function, glycerophospholipid molecular species composition, and normal rates of mitochondrial respiration and ATP production. In contrast, CMiPLA2γKO mice demonstrated attenuated Ca2+-induced mPTP opening that could be rapidly restored by the addition of palmitate and substantially reduced production of oxidized polyunsaturated fatty acids (PUFAs). Furthermore, myocardial ischemia/reperfusion (I/R) in CMiPLA2γKO mice (30 min of ischemia followed by 30 min of reperfusion in vivo) dramatically decreased oxidized fatty acid production in the ischemic border zones. Moreover, CMiPLA2γKO mice subjected to 30 min of ischemia followed by 24 h of reperfusion in vivo developed substantially less cardiac necrosis in the area-at-risk in comparison with their WT littermates. Furthermore, we found that membrane depolarization in murine heart mitochondria was sensitized to Ca2+ by the presence of oxidized PUFAs. Because mitochondrial membrane depolarization and calcium are known to activate iPLA2γ, these results are consistent with salvage of myocardium after I/R by iPLA2γ loss of function through decreasing mPTP opening, diminishing production of proinflammatory oxidized fatty acids, and attenuating the deleterious effects of abrupt increases in calcium ion on membrane potential during reperfusion. PMID:27453526

  5. MINE WASTE TECHNOLOGY PROGRAM PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT HIGHWALLS

    EPA Science Inventory

    This document summarizes the results of Mine Waste Technology Program Activity III, Project 26, Prevention of Acid Mine Drainage Generation from Open-Pit Highwalls. The intent of this project was to obtain performance data on the ability of four technologies to prevent the gener...

  6. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia

    PubMed Central

    Wilson, Rosamund J; Copley, J Brian

    2017-01-01

    Background Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. Scope A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Findings Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Conclusion Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance. PMID:28182142

  7. Ursolic Acid Inhibits Na+/K+-ATPase Activity and Prevents TNF-α-Induced Gene Expression by Blocking Amino Acid Transport and Cellular Protein Synthesis

    PubMed Central

    Yokomichi, Tomonobu; Morimoto, Kyoko; Oshima, Nana; Yamada, Yuriko; Fu, Liwei; Taketani, Shigeru; Ando, Masayoshi; Kataoka, Takao

    2011-01-01

    Pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, induce the expression of a wide variety of genes, including intercellular adhesion molecule-1 (ICAM-1). Ursolic acid (3β-hydroxy-urs-12-en-28-oic acid) was identified to inhibit the cell-surface ICAM-1 expression induced by pro-inflammatory cytokines in human lung carcinoma A549 cells. Ursolic acid was found to inhibit the TNF-α-induced ICAM-1 protein expression almost completely, whereas the TNF-α-induced ICAM-1 mRNA expression and NF-κB signaling pathway were decreased only partially by ursolic acid. In line with these findings, ursolic acid prevented cellular protein synthesis as well as amino acid uptake, but did not obviously affect nucleoside uptake and the subsequent DNA/RNA syntheses. This inhibitory profile of ursolic acid was similar to that of the Na+/K+-ATPase inhibitor, ouabain, but not the translation inhibitor, cycloheximide. Consistent with this notion, ursolic acid was found to inhibit the catalytic activity of Na+/K+-ATPase. Thus, our present study reveals a novel molecular mechanism in which ursolic acid inhibits Na+/K+-ATPase activity and prevents the TNF-α-induced gene expression by blocking amino acid transport and cellular protein synthesis. PMID:24970122

  8. Use of diphosphonates to correct disorders in calcium metabolism and mineral composition of bone tissue with 60-day hypokinesia in rats

    NASA Technical Reports Server (NTRS)

    Morukov, B. V.; Zaychik, V. YE.; Ivanov, V. M.; Orlov, O. I.

    1988-01-01

    Compounds of the diphosphonate group suppress bone resorption and bone tissue metabolism, from which it was assumed that they can be used for the prevention of osteoporosis and disorders of calcium homeostasis in humans during space flight. Two compounds of this group were used for preventive purposes in 60 day hypokinesia in rats. The results showed that diphosphonates have a marked effect on calcium metabolism and the condition of the bone tissues under conditions of long term hypokinesia: they reduce the content of ionized calcium in blood, delay the loss of calcium and phosphorus by the bone tissue, and to a considerable degree prevent reduction of bone density. This confirms the possibility of using compounds of this group for correcting and preventing changes of bone tissue and mineral metabolism during long term hypokinesia.

  9. Prevention of neural tube defects with folic acid: The Chinese experience.

    PubMed

    Ren, Ai-Guo

    2015-08-08

    Neural tube defects (NTDs) are a group of congenital malformations of the central nervous system that are caused by the closure failure of the embryonic neural tube by the 28(th) day of conception. Anencephaly and spina bifida are the two major subtypes. Fetuses with anencephaly are often stillborn or electively aborted due to prenatal diagnosis, or they die shortly after birth. Most infants with spina bifida are live-born and, with proper surgical treatment, can survive into adulthood. However, these children often have life-long physical disabilities. China has one of the highest prevalence of NTDs in the world. Inadequate dietary folate intake is believed to be the main cause of the cluster. Unlike many other countries that use staple fortification with folic acid as the public health strategy to prevent NTDs, the Chinese government provides all women who have a rural household registration and who plan to become pregnant with folic acid supplements, free of charge, through a nation-wide program started in 2009. Two to three years after the initiation of the program, the folic acid supplementation rate increased to 85% in the areas of the highest NTD prevalence. The mean plasma folate level of women during early and mid-pregnancy doubled the level before the program was introduced. However, most women began taking folic acid supplements when they knew that they were pregnant. This is too late for the protection of the embryonic neural tube. In a post-program survey of the women who reported folic acid supplementation, less than a quarter of the women began taking supplements prior to pregnancy, indicating that the remaining three quarters of the fetuses remained unprotected during the time of neural tube formation. Therefore, staple food fortification with folic acid should be considered as a priority in the prevention of NTDs.

  10. Resveratrol-induced antinociception is involved in calcium channels and calcium/caffeine-sensitive pools.

    PubMed

    Pan, Xiaoyu; Chen, Jiechun; Wang, Weijie; Chen, Ling; Wang, Lin; Ma, Quan; Zhang, Jianbo; Chen, Lichao; Wang, Gang; Zhang, Meixi; Wu, Hao; Cheng, Ruochuan

    2017-02-07

    Resveratrol has been widely investigated for its potential health properties, although little is known about its mechanism in vivo. Previous studies have indicated that resveratrol produces antinociceptive effects in mice. Calcium channels and calcium/caffeine-sensitive pools are reported to be associated with analgesic effect. The present study was to explore the involvement of Ca2+ channel and calcium/caffeine-sensitive pools in the antinociceptive response of resveratrol. Tail-flick test was used to assess antinociception in mice treated with resveratrol or the combinations of resveratrol with MK 801, nimodipine, CaCl2, ryanodine and ethylene glycol tetraacetic acid (EGTA), respectively. The Ca2+/calmodulin-dependent protein kinase II (CaMKII) and brain-derived neurotrophic factor (BDNF) levels in the spinal cord were also investigated when treated with the above drugs. The results showed that resveratrol increased the tail flick latency in the tail-flick test, in dose-dependent manner. N-methyl-D-aspartate (NMDA) glutamate receptor antagonist MK 801 potentiated the antinociceptive effects of sub-threshold dose of resveratrol at 10 mg/kg. Ca2+ channel blocker, however, abolished the antinociceptive effects of resveratrol. In contrast to these results, EGTA or ryanodine treatment (i.c.v.) potentiated resveratrol-induced antinociception. There was a significant decrease in p-CaMKII and an increase in BDNF expression in the spinal cord when combined with MK 801, nimodipine, ryanodine and EGTA. While an increase in p-CaMKII level and a decrease in BDNF expression were observed when high dose of resveratrol combined with CaCl2. These findings suggest that resveratrol exhibits the antinociceptive effects by inhibition of calcium channels and calcium/caffeine-sensitive pools.

  11. Degradable biocomposite of nano calcium-deficient hydroxyapatite-multi(amino acid) copolymer

    PubMed Central

    Li, Hong; Gong, Min; Yang, Aiping; Ma, Jian; Li, Xiangde; Yan, Yonggang

    2012-01-01

    Background and methods A nano calcium-deficient hydroxyapatite (n-CDHA)-multi(amino acid) copolymer (MAC) composite bone substitute biomaterial was prepared using an in situ polymerization method. The composition, structure, and compressive strength of the composite was characterized, and the in vitro degradability in phosphate-buffered solution and preliminary cell responses to the composite were investigated. Results The composite comprised n-CDHA and an amide linkage copolymer. The compressive strength of the composite was in the range of 88–129 MPa, varying with the amount of n-CDHA in the MAC (ranging from 10 wt% to 50 wt%). Weight loss from the composite increased (from 32.2 wt% to 44.3 wt%) with increasing n-CDHA content (from 10 wt% to 40 wt%) in the MAC after the composite was soaked in phosphate-buffered solution for 12 weeks. The pH of the soaking medium varied from 6.9 to 7.5. MG-63 cells with an osteogenic phenotype were well adhered and spread on the composite surface. Viability and differentiation increased with time, indicating that the composite had no negative effects on MG-63 cells. Conclusion The n-CDHA-MAC composite had good cytocompatibility and has potential to be used as a bone substitute. PMID:22457591

  12. Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

    PubMed Central

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward

    2013-01-01

    To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

  13. A specific amino acid formula prevents alcoholic liver disease in rodents.

    PubMed

    Tedesco, Laura; Corsetti, Giovanni; Ruocco, Chiara; Ragni, Maurizio; Rossi, Fabio; Carruba, Michele O; Valerio, Alessandra; Nisoli, Enzo

    2018-05-01

    Chronic alcohol consumption promotes mitochondrial dysfunction, oxidative stress, defective protein metabolism, and fat accumulation in hepatocytes (liver steatosis). Inadequate amino acid metabolism is worsened by protein malnutrition, frequently present in alcohol-consuming patients, with reduced circulating branched-chain amino acids (BCAAs). Here we asked whether dietary supplementation with a specific amino acid mixture, enriched in BCAAs (BCAAem) and able to promote mitochondrial function in muscle of middle-aged rodents, would prevent mitochondrial dysfunction and liver steatosis in Wistar rats fed on a Lieber-DeCarli ethanol (EtOH)-containing liquid diet. Supplementation of BCAAem, unlike a mixture based on the amino acid profile of casein, abrogated the EtOH-induced fat accumulation, mitochondrial impairment, and oxidative stress in liver. These effects of BCAAem were accompanied by normalization of leucine, arginine, and tryptophan levels, which were reduced in liver of EtOH-consuming rats. Moreover, although the EtOH exposure of HepG2 cells reduced mitochondrial DNA, mitochondrial transcription factors, and respiratory chain proteins, the BCAAem but not casein-derived amino acid supplementation halted this mitochondrial toxicity. Nicotinamide adenine dinucleotide levels and sirtuin 1 (Sirt1) expression, as well as endothelial nitric oxide (eNOS) and mammalian/mechanistic target of rapamycin (mTOR) signaling pathways, were downregulated in the EtOH-exposed HepG2 cells. BCAAem reverted these molecular defects and the mitochondrial dysfunction, suggesting that the mitochondrial integrity obtained with the amino acid supplementation could be mediated through a Sirt1-eNOS-mTOR pathway. Thus a dietary activation of the mitochondrial biogenesis and function by a specific amino acid supplement protects against the EtOH toxicity and preserves the liver integrity in mammals. NEW & NOTEWORTHY Dietary supplementation of a specific amino acid formula prevents both

  14. Five year study of etidronate and/or calcium as prevention and treatment for osteoporosis and fractures in patients with asthma receiving long term oral and/or inhaled glucocorticoids

    PubMed Central

    Campbell, I; Douglas, J; Francis, R; Prescott, R; Reid, D

    2004-01-01

    Background: Glucocorticoids are associated with a reduction in bone density and an increased risk of fracture. Concurrent treatment with bisphosphonates reduces bone loss and may prevent fractures. A randomised study was performed to determine whether treatment with cyclical etidronate and/or calcium for 5 years prevents fractures or reverses/reduces bone loss in patients receiving glucocorticoid treatment for asthma. Methods: A multicentre, randomised, parallel group comparison of etidronate alone, calcium alone, etidronate + calcium, and no treatment, with stratification according to level of glucocorticoid exposure was carried out in 39 chest clinics in the UK. Three hundred and forty nine postmenopausal female and male outpatients with asthma aged 50–70 years were randomised. The main outcome measures were fractures and changes in bone mineral density (BMD). Results: Overall, 8% of the patients experienced symptomatic fractures and 17.5% developed either a symptomatic fracture and/or a semiquantitative vertebral fracture by the end of 5 years There were no significant differences between the four treatment groups. Comparing etidronate with no etidronate, the rates of new fractures were not significantly different for symptomatic fractures (OR 1.07 (95% CI 0.46 to 2.47)) or for any fractures (OR 0.82 (95% CI 0.45 to 1.47)). For the comparison of calcium with no calcium the corresponding ORs were 1.43 (95% CI 0.62 to 3.33) and 0.91 (95% CI 0.50 to 1.63). In post hoc analysis the effect of etidronate was greater in women than in men (interaction p value 0.02) with the fracture incidence roughly halved (OR 0.39, 95% CI 0.14 to 0.99). Etidronate increased BMD at the lumbar spine by 4.1% (p = 0.001) while calcium had no significant effect. At the proximal femur the effects of treatment were not significant (relative increases etidronate 1.6%; calcium 1.1%). The rate of new fractures in patients with fractures at entry (23.7%) was higher than in those without

  15. [Percentage of uric acid calculus and its metabolic character in Dongjiang River valley].

    PubMed

    Chong, Hong-Heng; An, Geng

    2009-02-15

    To study the percentage of uric acid calculus in uroliths and its metabolic character in Dongjiang River valley. To analyze the chemical composition of 290 urinary stones by infrared (IR) spectroscopy and study the ratio changes of uric acid calculus. Uric acid calculus patients and healthy people were studied. Personal characteristics, dietary habits were collected. Conditional logistic regression was used for data analysis and studied the dietary risk factors of uric acid calculus. Patients with uric acid calculus, calcium oxalate and those without urinary calculus were undergone metabolic evaluation analysis. The results of uric acid calculus patients compared to another two groups to analysis the relations between the formation of uric acid calculus and metabolism factors. Uric acid calculi were found in 53 cases (18.3%). The multiple logistic regression analysis suggested that low daily water intake, eating more salted and animal food, less vegetable were very closely associated with uric acid calculus. Comparing to calcium oxalate patients, the urine volume, the value of pH, urine calcium, urine oxalic acid were lower, but uric acid was higher than it. The value of pH, urine oxalic acid and citric acid were lower than them, but uric acid and urine calcium were higher than none urinary calculus peoples. Blood potassium and magnesium were lower than them. The percentage of uric acid stones had obvious advanced. Less daily water intake, eating salted food, eating more animal food, less vegetables and daily orange juice intake, eating sea food are the mainly dietary risk factors to the formation of uric acid calculus. Urine volume, the value of pH, citric acid, urine calcium, urine uric acid and the blood natrium, potassium, magnesium, calcium, uric acid have significant influence to the information of uric acid stones.

  16. Tetany: quantitative interrelationships between calcium and alkalosis.

    PubMed

    Edmondson, J W; Brashear, R E; Li, T K

    1975-04-01

    Tetany occurs with hypocalcemia and alkalosis or both. The interrelationship of calcium and acid-base balance necessary for inducing tetany, the role of the central nervous system, and the rate of development of hypocalcemia have been investigated. Tetany occurred in less than 50 percent of one group of dogs made alkalotic by hyperventilation or made hypocalcemic by infusion of ethylene glycol-bis(beta-amino ethyl ether) N, N'-tetraacetate. In contrast, hypocalcemia combined with hypocapnic alkalosis always produced tetany. Slowly evolving hypocalcemia was achieved inanother group of dogs by thyroparathyroidectomy, and tetany was induced postoperatively by hypocapnic alkalosis. An identical relationship between serum calcium ion concentration and arterial pH or CO2 tension was found in both groups. Tetany could not be related to the cerebrospinal fluid (CSF) calcium ion content in either group. Hypocalcemia and alkalosis are therefore coparticipants in the development of tetany and are independent of the rate of development of hypocalcemia and of CSF calcium ion concentration. The importance of alkalosis in tetany with hypoparathyroidism is emphasized.

  17. Formate oxidation-driven calcium carbonate precipitation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert; Boon, Nico

    2014-08-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such asammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2(-1) calcium carbonate precipitate yield was obtained when a culture of 10(9) cells ml(-1) and 5 g of calcium formate liter(-)1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry.

  18. Formate Oxidation-Driven Calcium Carbonate Precipitation by Methylocystis parvus OBBP

    PubMed Central

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert

    2014-01-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such as ammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2−1 calcium carbonate precipitate yield was obtained when a culture of 109 cells ml−1 and 5 g of calcium formate liter−1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry. PMID:24837386

  19. Hexavalent chromium damages chamomile plants by alteration of antioxidants and its uptake is prevented by calcium.

    PubMed

    Kováčik, Jozef; Babula, Petr; Hedbavny, Josef; Klejdus, Bořivoj

    2014-05-30

    Toxicity of low (3μM) and high (60 and 120μM) concentrations of hexavalent chromium/Cr(VI) in chamomile plants was studied. Fluorescence staining confirmed reduction of Cr(VI) to Cr(III). Cr was mainly accumulated in the roots with translocation factor <0.007. Notwithstanding this, both shoots and roots revealed increase in oxidative stress and depletion of glutathione, total thiols, ascorbic acid and activities of glutathione reductase and partially ascorbate peroxidase mainly at 120μM Cr. Though some protective mechanisms were detected (elevation of nitric oxide, enhancement of GPX activity and increase in phenols and lignin), this was not sufficient to counteract the oxidative damage. Consequently, soluble proteins, tissue water content and biomass production were considerably depleted. Surprising increase in some mineral nutrients in roots (Ca, Fe, Zn and Cu) was also detected. Subsequent experiment confirmed that exogenous calcium suppressed oxidative symptoms and Cr uptake but growth of chamomile seedlings was not improved. Alteration of naturally present reductants could be a reason for Cr(III) signal detected using specific fluorescence reagent: in vitro assay confirmed disappearance of ascorbic acid in equimolar mixture with dichromate (>96% at pH 4 and 7) while such response of glutathione was substantially less visible. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Effect of calcium salt of long-chain fatty acids and alfalfa supplementation on performance of Holstein bulls.

    PubMed

    He, Yang; Niu, Wenjing; Qiu, Qinghua; Xia, Chuanqi; Shao, Taoqi; Wang, Haibo; Li, Qianwen; Yu, Zhantao; Gao, Zhibiao; Rahman, Muhammad Aziz Ur; Su, Huawei; Cao, Binghai

    2018-01-09

    The purpose of this study was to assess the effects of calcium salt of long-chain fatty acids (CSFA) and alfalfa on beef cattle in the late fattening. 48 Holstein bulls were selected and randomly divided into 4 groups, feeding four dietary that Leymus chinensis with (LC) or with no (LN) 2.4% CSFA, and alfalfa replaced 50% Leymus chinensis with (AC) or with no (AN) 2.4% CSFA. The results indicated that alfalfa improved the feed conversion rate ( P < 0.05). CSFA increased serum low density lipoprotein cholesterol, and reduced the cooking loss of Longissimus muscle ( P < 0.05). CSFA and alfalfa reduced Acetate/Propionate. Alfalfa and CASF had significant additive effects on the apparent digestibility of dry matter, crude protein, neutral detergent fiber, acid detergent fiber, organic matter and rumen fermentation for acetate, isobutyrate, butyrate, isovalerate, total volatile fatty acids ( P < 0.05). CSFA increased microbial diversity index when compared with alfalfa ( P < 0.05), but no significant differences were detected in bacterial genera abundances among diets. The relative abundances of rumen bacterial genera have significant correlation with apparent digestibility of nutrients, rumen fermentation characteristics and serum biochemical parameters ( P < 0.05). These results comprehensively evaluated the additive effects of alfalfa and CSFA on the application in Holstein bulls.

  1. Calcium in the regulation of gravitropism by light

    NASA Technical Reports Server (NTRS)

    Perdue, D. O.; LaFavre, A. K.; Leopold, A. C.

    1988-01-01

    The red light requirement for positive gravitropism in roots of corn (Zea mays cv "Merit") provides an entry for examining the participation of calcium in gravitropism. Applications of calcium chelators inhibit the light response. Calcium channel blockers (verapamil, lanthanum) can also inhibit the light response, and a calcium ionophore, A23187, can substitute for light. One can substitute for red light by treatments which have elsewhere been shown to trigger Ca2+ influx into the cytosol, e.g. heat or cold shock. Agents which are known to be agonists of the phosphatidylinositol second messenger system (serotonin, 2,4-dichlorophenoxyacetic acid, deoxycholate) can each partially substitute for the red light, and Li+ can inhibit the light effect. These experiments suggest that the induction of positive gravitropism by red light involves a rise in cytoplasmic Ca2+ concentration, and that a contribution to this end may be made by the phosphatidylinositol second messenger system.

  2. Dietary Alfalfa and Calcium Salts of Long-Chain Fatty Acids Alter Protein Utilization, Microbial Populations, and Plasma Fatty Acid Profile in Holstein Freemartin Heifers.

    PubMed

    He, Yang; Qiu, Qinghua; Shao, Taoqi; Niu, Wenjing; Xia, Chuanqi; Wang, Haibo; Li, Qianwen; Gao, Zhibiao; Yu, Zhantao; Su, Huawei; Cao, Binghai

    2017-12-20

    This study presented the effects of alfalfa and calcium salts of long-chain fatty acids (CSFA) on feed intake, apparent digestibility, rumen fermentation, microbial community, plasma biochemical parameters, and fatty acid profile in Holstein freemartin heifers. Eight Holstein freemartin heifers were randomly divided into a 4 × 4 Latin Square experiment with 2 × 2 factorial diets, with or without alfalfa or CSFA. Dietary supplementation of CSFA significantly increased the apparent digestibility of dry matter, crude protein, neutral detergent fiber, organic matter, and significantly reduced N retention (P < 0.05). CSFA increased the concentration of ammonia nitrogen in the ruminal fluid (P < 0.05), but alfalfa increased the concentration of valerate and isovalerate (P < 0.05). CSFA increased the concentration of ammonia nitrogen and the relative population of Streptococcus bovis in the rumen (P < 0.05) and inhibited the relative population of Ruminococcus flavefaciens, methanogens, and protozoa (P < 0.05). Alfalfa instead of Leymus chinensis increased the relative population of Butyrivibrio fibrisolvens and Ruminobacter amylophilus in the rumen (P < 0.05) and reduced the relative population of the Ruminococcus albus and Megasphaera elsdenii (P < 0.05). Supplemental CSFA increased the concentration of cholesterol and low-density lipoprotein cholesterol in the plasma (P < 0.05). And it also altered the composition of fatty acids in the plasma, which was expressed in reducing saturated fatty acid (ΣSFA) ratio and C14-C17 fatty acids proportion except C16:0 (P < 0.05) and increasing the proportion of polyunsaturated fatty acid (ΣPUFA) and unsaturated fatty acid (ΣUFA) (P < 0.05). The results showed that alfalfa and CSFA had interaction effect on the apparent digestibility of ether extracts, plasma triglyceride concentration, isobutyrate concentration, and Ruminococcus albus relative abundance in the rumen. It was concluded that alfalfa substituting Leymus chinensis

  3. A human intermediate conductance calcium-activated potassium channel

    PubMed Central

    Ishii, Takahiro M.; Silvia, Christopher; Hirschberg, Birgit; Bond, Chris T.; Adelman, John P.; Maylie, James

    1997-01-01

    An intermediate conductance calcium-activated potassium channel, hIK1, was cloned from human pancreas. The predicted amino acid sequence is related to, but distinct from, the small conductance calcium-activated potassium channel subfamily, which is ≈50% conserved. hIK1 mRNA was detected in peripheral tissues but not in brain. Expression of hIK1 in Xenopus oocytes gave rise to inwardly rectifying potassium currents, which were activated by submicromolar concentrations of intracellular calcium (K0.5 = 0.3 μM). Although the K0.5 for calcium was similar to that of small conductance calcium-activated potassium channels, the slope factor derived from the Hill equation was significantly reduced (1.7 vs. 3.5). Single-channel current amplitudes reflected the macroscopic inward rectification and revealed a conductance level of 39 pS in the inward direction. hIK1 currents were reversibly blocked by charybdotoxin (Ki = 2.5 nM) and clotrimazole (Ki = 24.8 nM) but were minimally affected by apamin (100 nM), iberiotoxin (50 nM), or ketoconazole (10 μM). These biophysical and pharmacological properties are consistent with native intermediate conductance calcium-activated potassium channels, including the erythrocyte Gardos channel. PMID:9326665

  4. Effect of ascorbic acid on prevention of hypercholesterolemia induced atherosclerosis.

    PubMed

    Das, S; Ray, R; Snehlata; Das, N; Srivastava, L M

    2006-04-01

    The notion that oxidation of lipids and propagation of free radicals may contribute to the pathogenesis of atherosclerosis is supported by a large body of evidence. To circumvent the damage caused by oxygen free radicals, antioxidants are needed which provide the much needed neutralization of free radical by allowing the pairing of electrons. In this study we have investigated the effect of ascorbic acid, a water soluble antioxidant on the development of hypercholesterolemia induced atherosclerosis in rabbits. Rabbits were made hypercholesterolemic and atherosclerotic by feeding 100 mg cholesterol/day. Different doses of ascorbic acid were administered to these rabbits. Low dose of ascorbic acid (0.5 mg/100 g body weight/day) did not have any significant effect on the percent of total area covered by atherosclerotic plaque. However, ascorbic acid when fed at a higher dose (15 mg/100 g body weight/day) was highly effective in reducing the atherogenecity. With this dose the percent of total surface area covered by atherosclerotic plaque was significantly less (p < 0.001). This suggests that use of ascorbic acid may have great promise in the prevention of hypercholesterolemia induced atherosclerosis.

  5. Calcium absorption from apple and orange juice fortified with calcium citrate malate (CCM).

    PubMed

    Andon, M B; Peacock, M; Kanerva, R L; De Castro, J A

    1996-06-01

    Determine calcium (Ca) absorption from Ca fortified orange and apple juice. Absorbability was assessed by measuring 45Ca absorption in healthy women (mean age 57 years, n = 57/group) and whole body 47Ca retention in adult female beagle dogs (n = 6/group) and young adult male rats (n = 6/group). Women received 6.24 mmol (250 mg) Ca as calcium citrate malate fortified orange juice (CCM-OJ) or apple juice (CCM-AJ). Dogs received 3.12 mmol (125 mg) Ca as CCM-OJ or CCM-AJ. Rats were administered 0.15 mmol (6 mg) Ca as either milk, CCM-OJ, or CCM-AJ. Additional 47Ca whole body retention experiments in rats measured the effects of differences in the carbohydrate and organic acid contents of the juices on Ca absorption. Mean +/- SEM percent Ca fractional absorption was greater (p < 0.003) in women who consumed CCM-AJ (42 +/- 2%) than those who consumed CCM-OJ (36 +/- 1%). Ca retention in dogs was 15 +/- 1% for CCM-OJ and 29 +/- 2% for CCM-AJ (p < 0.001). Ca retention was significantly different (p < 0.05) in rats administered milk (42 +/- 2%), CCM-OJ (52 +/- 2%), or CCM-AJ (61 +/- 2%). By manipulating the carbohydrate and organic acid concentrations of test solutions to mimic the composition of Ca fortified juices, we found that the greater fructose and lower organic acid content of apple juice accounted for its greater Ca absorbability. CCM fortified versions of orange and apple juice have high Ca absorbability and are potentially important vehicles for increasing dietary Ca intake. The greater Ca absorption from CCM-AJ compared with CCM-OJ is accounted for by differences in the carbohydrate and organic acid content of the juices. These data suggest that by modifying common beverage ingredients, products with even greater Ca absorbability could be formulated.

  6. [Prevention of osteoporosis by foods and dietary supplements. Chocolate malt drink MILO: nutrition in children and calcium absorption].

    PubMed

    Fukushima, Yoichi; Kumagai, Akiko

    2006-10-01

    Calcium is not sufficiently consumed by Japanese at any age groups. Childhood is an important period, when they should earn bone minerals to reach higher peak bone mass for reducing the risk of osteoporosis in their later life. Children require higher calcium consumption per body weight than adults, and also establish their dietary pattern in this period. MILO has attracted widespread popularity as a good-taste chocolate-flavored malt drink with balanced nutrients for children. We developed FOSHU MILO with fructooligosaccharides (FOS) aiming at improving absorption of calcium, which is originally rich in the products. Using the calcium stable isotope (44)Ca, we found that the urinary excretion in the subject fed the products with FOS was higher than that of control product without FOS, suggesting that the FOSHU MILO is effective in promoting calcium absorption from the intestines. MILO could contribute to bone health by increasing consumption of calcium and/or improving the calcium bioavailability.

  7. Preparation and biological efficacy of haddock bone calcium tablets

    NASA Astrophysics Data System (ADS)

    Huo, Jiancong; Deng, Shanggui; Xie, Chao; Tong, Guozhong

    2010-03-01

    To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking (alkalinealcohol method) and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results show that the optimal parameters for the alkalinealcohol method are: NaOH concentration 1 mol/L, immersion time 30 h; ethanol concentration 60%, immersion time 15 h. A mixture of 2% polyvinylpyrrolidone in ethanol was used as an excipient at a ratio of 1:2 to full-cream milk powder, without the use of a disintegrating agent. This process provided satisfactory tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2 g·kg-1·d-1 or 5g·kg-1·d-1 significantly increased blood calcium and phosphorus levels and bone calcium content in rats. Therefore, these tablets could be used for calcium supplementation and prevent osteoporosis. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the added milk, may play positive roles in increasing absorption ratio.

  8. Endotrophic Calcium, Strontium, and Barium Spores of Bacillus megaterium and Bacillus cereus1

    PubMed Central

    Foerster, Harold F.; Foster, J. W.

    1966-01-01

    Foerster, Harold F. (The University of Texas, Austin), and J. W. Foster. Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus. J. Bacteriol. 91:1333–1345. 1966.—Spores were produced by washed vegetative cells suspended in deionized water supplemented with CaCl2, SrCl2, or BaCl2. Normal, refractile spores were produced in each case; a portion of the barium spores lost refractility and darkened. Thin-section electron micrographs revealed no apparent anatomical differences among the three types of spores. Analyses revealed that the different spore types were enriched specifically in the metal to which they were exposed during sporogenesis. The calcium content of the strontium and the barium spores was very small. From binary equimolar mixtures of the metal salts, endotrophic spores accumulated both metals to nearly the same extent. Viability of the barium spores was considerably less than that of the other two types. Strontium and barium spores were heat-resistant; however, calcium was essential for maximal heat resistance. Significant differences existed in the rates of germination; calcium spores germinated fastest, strontium spores were slower, and barium spores were slowest. Calcium-barium and calcium-strontium spores germinated readily. Endotrophic calcium and strontium spores germinated without the prior heat activation essential for growth spores. Chemical germination of the different metal-type spores with n-dodecylamine took place at the same relative rates as physiological germination. Heat-induced release of dipicolinic acid occurred much faster with barium and strontium spores than with calcium spores. The washed “coat fraction” from disrupted spores contained little of the spore calcium but most of the spore barium. The metal in this fraction was released by dilute acid. The demineralized coats reabsorbed calcium and barium at neutral pH. Images PMID:4956334

  9. Ferulic acid prevents liver injury and increases the anti-tumor effect of diosbulbin B in vivo.

    PubMed

    Wang, Jun-ming; Sheng, Yu-chen; Ji, Li-li; Wang, Zheng-tao

    2014-06-01

    The present study is designed to investigate the protection by ferulic acid against the hepatotoxicity induced by diosbulbin B and its possible mechanism, and further observe whether ferulic acid augments diosbulbin B-induced anti-tumor activity. The results show that ferulic acid decreases diosbulbin B-increased serum alanine transaminase/aspartate transaminase (ALT/AST) levels. Ferulic acid also decreases lipid peroxide (LPO) levels which are elevated in diosbulbin B-treated mice. Histological evaluation of the liver demonstrates hydropic degeneration in diosbulbin B-treated mice, while ferulic acid reverses this injury. Moreover, the activities of copper- and zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) are decreased in the livers of diosbulbin B-treated mice, while ferulic acid reverses these decreases. Further results demonstrate that the mRNA expressions of CuZn-SOD and CAT in diosbulbin B-treated mouse liver are significantly decreased, while ferulic acid prevents this decrease. In addition, ferulic acid also augments diosbulbin B-induced tumor growth inhibition compared with diosbulbin B alone. Taken together, the present study shows that ferulic acid prevents diosbulbin B-induced liver injury via ameliorating diosbulbin B-induced liver oxidative stress injury and augments diosbulbin B-induced anti-tumor activity.

  10. In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

    PubMed

    Peng, Sui; Huo, Xiaofang; Rezaei, Davood; Zhang, Qiuyang; Zhang, Xi; Yu, Chunhua; Asanuma, Kiyotaka; Cheng, Edaire; Pham, Thai H; Wang, David H; Chen, Minhu; Souza, Rhonda F; Spechler, Stuart Jon

    2014-07-15

    Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-κB in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal perfusion with DCA (250 μM) at baseline and after 8 wk of oral UDCA treatment. DNA damage was assessed by phospho-H2AX expression, neutral CometAssay, and phospho-H2AX nuclear foci formation. Quantitative PCR was performed for antioxidants including catalase and GPX1. Nrf2, catalase, and GPX1 were knocked down with siRNAs. Reporter assays were performed using a plasmid construct containing antioxidant responsive element. In patients, baseline esophageal perfusion with DCA significantly increased phospho-H2AX and phospho-p65 in Barrett's metaplasia. Oral UDCA increased GPX1 and catalase levels in Barrett's metaplasia and prevented DCA perfusion from inducing DNA damage and NF-κB activation. In cells, DCA-induced DNA damage and NF-κB activation was prevented by 24-h pretreatment with UDCA, but not by mixing UDCA with DCA. UDCA activated Nrf2 signaling to increase GPX1 and catalase expression, and protective effects of UDCA pretreatment were blocked by siRNA knockdown of these antioxidants. UDCA increases expression of antioxidants that prevent toxic bile acids from causing DNA damage and NF-κB activation in Barrett's metaplasia. Elucidation of this molecular pathway for UDCA protection provides rationale for clinical trials on UDCA for chemoprevention in Barrett's esophagus. Copyright © 2014 the American Physiological Society.

  11. In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids

    PubMed Central

    Peng, Sui; Huo, Xiaofang; Rezaei, Davood; Zhang, Qiuyang; Zhang, Xi; Yu, Chunhua; Asanuma, Kiyotaka; Cheng, Edaire; Pham, Thai H.; Wang, David H.; Chen, Minhu; Spechler, Stuart Jon

    2014-01-01

    Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-κB in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal perfusion with DCA (250 μM) at baseline and after 8 wk of oral UDCA treatment. DNA damage was assessed by phospho-H2AX expression, neutral CometAssay, and phospho-H2AX nuclear foci formation. Quantitative PCR was performed for antioxidants including catalase and GPX1. Nrf2, catalase, and GPX1 were knocked down with siRNAs. Reporter assays were performed using a plasmid construct containing antioxidant responsive element. In patients, baseline esophageal perfusion with DCA significantly increased phospho-H2AX and phospho-p65 in Barrett's metaplasia. Oral UDCA increased GPX1 and catalase levels in Barrett's metaplasia and prevented DCA perfusion from inducing DNA damage and NF-κB activation. In cells, DCA-induced DNA damage and NF-κB activation was prevented by 24-h pretreatment with UDCA, but not by mixing UDCA with DCA. UDCA activated Nrf2 signaling to increase GPX1 and catalase expression, and protective effects of UDCA pretreatment were blocked by siRNA knockdown of these antioxidants. UDCA increases expression of antioxidants that prevent toxic bile acids from causing DNA damage and NF-κB activation in Barrett's metaplasia. Elucidation of this molecular pathway for UDCA protection provides rationale for clinical trials on UDCA for chemoprevention in Barrett's esophagus. PMID:24852569

  12. In vitro solubility of calcium, iron and zinc in relation to phytic acid levels in rice-based consumer products in China.

    PubMed

    Liang, Jianfen; Han, Bei-Zhong; Nout, M J Robert; Hamer, Robert J

    2010-02-01

    In vitro solubility of calcium, iron and zinc in relation to phytic acid (PA) levels in 30 commercial rice-based foods from China was studied. Solubility of minerals and molar ratios of PA to minerals varied with degrees of processing. In primary products, [PA]/[Ca] values were less than 5 and [PA]/[Fe] and [PA]/[Zn] similarly ranged between 5 and 74, with most values between 20 and 30. [PA]/[mineral] molar ratios in intensively processed products were lower. Solubility of calcium ranged from 0% to 87%, with the lowest in brown rice (12%) and the highest in infant foods (50%). Iron solubility in two-thirds of samples was lower than 30%, and that of zinc narrowly ranged from 6% to 30%. Solubility of minerals was not significantly affected by [PA]/[mineral]. At present, neither primary nor intensively processed rice-based products are good dietary sources of minerals. Improvements should be attempted by dephytinization, mineral fortification or, preferably, combination of both.

  13. Characterization of calcium oxalate biominerals in some (non-Cactaceae) succulent plant species.

    PubMed

    Monje, Paula V; Baran, Enrique J

    2010-01-01

    The water-accumulating leaves of crassulacean acid metabolism plants belonging to five different families were investigated for the presence of biominerals by infrared spectroscopic and microscopic analyses. Spectroscopic results revealed that the mineral present in succulent species of Agavaceae, Aizoaceae, and Asphodelaceae was calcium oxalate monohydrate (whewellite, CaC2O4 x H2O). Crystals were predominantly found as raphides or solitary crystals of various morphologies. However, representative Crassulaceae members and a succulent species of Asteraceae did not show the presence of biominerals. Overall, these results suggest no correlation between calcium oxalate generation and crassulacean acid metabolism in succulent plants.

  14. Calcium

    MedlinePlus

    ... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

  15. Modulation of bicarbonate secretion in rabbit duodenum: the role of calcium.

    PubMed

    Hogan, D L; Yao, B; Isenberg, J I

    1998-01-01

    Surface epithelial bicarbonate secretion protects the proximal duodenum from acid peptic injury. Cyclic adenosine monophosphate and calcium serve as intracellular mediators of intestinal transport. Experiments were performed to examine whether calcium participates in duodenal bicarbonate transport. Stripped duodenal mucosa from rabbits was studied in Ussing chambers. HCO3- transport was stimulated by the calcium ionophore A23187, carbachol, vasoactive intestinal peptide, prostaglandin E2, dibutyryl-cyclic adenosine monophosphate, and electrical field stimulation. A23187 stimulated HCO3- secretion and Isc; tetrodotoxin failed to inhibit this effect. The calcium-channel blocker verapamil abolished HCO3- secretion stimulated by carbachol, vasoactive intestinal peptide, and electrical field stimulation, but failed to alter basal, prostaglandin E2- or dibutyryl-cyclic adenosine monophosphate-stimulated HCO3- secretion. Therefore, calcium is likely required during stimulation of duodenal epithelial HCO3- transport by carbachol, vasoactive intestinal peptide, and electrical field stimulation. Prostaglandin E2 and dibutyryl-cyclic adenosine monophosphate appear to activate duodenal HCO3- secretion by a calcium-independent pathway(s).

  16. Preparation and Evaluation of the Chelating Nanocomposite Fabricated with Marine Algae Schizochytrium sp. Protein Hydrolysate and Calcium.

    PubMed

    Lin, Jiaping; Cai, Xixi; Tang, Mengru; Wang, Shaoyun

    2015-11-11

    Marine algae have been becoming a popular research topic because of their biological implication. The algae peptide-based metal-chelating complex was investigated in this study. Schizochytrium sp. protein hydrolysate (SPH) possessing high Ca-binding capacity was prepared through stepwise enzymatic hydrolysis to a degree of hydrolysis of 22.46%. The nanocomposites of SPH chelated with calcium ions were fabricated in aqueous solution at pH 6 and 30 °C for 20 min, with the ratio of SPH to calcium 3:1 (w/w). The size distribution showed that the nanocomposite had compact structure with a radius of 68.16 ± 0.50 nm. SPH was rich in acidic amino acids, accounting for 33.55%, which are liable to bind with calcium ions. The molecular mass distribution demonstrated that the molecular mass of SPH was principally concentrated at 180-2000 Da. UV scanning spectroscopy and Fourier transform infrared spectroscopy suggested that the primary sites of calcium-binding corresponded to the carboxyl groups, carbonyl groups, and amino groups of SPH. The results of fluorescent spectroscopy, size distribution, atomic force microscope, and (1)H nuclear magnetic resonance spectroscopy suggested that calcium ions chelated with SPH would cause intramolecular and intermolecular folding and aggregating. The SPH-calcium chelate exerted remarkable stability and absorbability under either acidic or basic conditions, which was in favor of calcium absorption in the gastrointestinal tracts of humans. The investigation suggests that SPH-calcium chelate has the potential prospect to be utilized as a nutraceutical supplement to improve bone health in the human body.

  17. Preparation, Physical-Chemical Characterization, and Cytocompatibility of Polymeric Calcium Phosphate Cements

    PubMed Central

    Khashaba, Rania M.; Moussa, Mervet; Koch, Christopher; Jurgensen, Arthur R.; Missimer, David M.; Rutherford, Ronny L.; Chutkan, Norman B.; Borke, James L.

    2011-01-01

    Aim. Physicochemical mechanical and in vitro biological properties of novel formulations of polymeric calcium phosphate cements (CPCs) were investigated. Methods. Monocalcium phosphate, calcium oxide, and synthetic hydroxyapatite were combined with either modified polyacrylic acid, light activated polyalkenoic acid, or polymethyl vinyl ether maleic acid to obtain Types I, II, and III CPCs. Setting time, compressive and diametral strength of CPCs was compared with zinc polycarboxylate cement (control). Specimens were characterized using X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. In vitro cytotoxicity of CPCs and control was assessed. Results. X-ray diffraction analysis showed hydroxyapatite, monetite, and brushite. Acid-base reaction was confirmed by the appearance of stretching peaks in IR spectra of set cements. SEM revealed rod-like crystals and platy crystals. Setting time of cements was 5–12 min. Type III showed significantly higher strength values compared to control. Type III yielded high biocompatibility. Conclusions. Type III CPCs show promise for dental applications. PMID:21941551

  18. Heteromerization of G2A and OGR1 enhances proton sensitivity and proton-induced calcium signals.

    PubMed

    Huang, Ya-Han; Su, Yeu-Shiuan; Chang, Chung-Jen; Sun, Wei-Hsin

    2016-12-01

    Proton-sensing G-protein-coupled receptors (GPCRs; OGR1, GPR4, G2A, TDAG8), with full activation at pH 6.4 ∼ 6.8, are important to pH homeostasis, immune responses and acid-induced pain. Although G2A mediates the G13-Rho pathway in response to acid, whether G2A activates Gs, Gi or Gq proteins remains debated. In this study, we examined the response of this fluorescence protein-tagged OGR1 family to acid stimulation in HEK293T cells. G2A did not generate detectable intracellular calcium or cAMP signals or show apparent receptor redistribution with moderate acid (pH ≥ 6.0) stimulation but reduced cAMP accumulation under strong acid stimulation (pH ≤ 5.5). Surprisingly, coexpression of OGR1- and G2A-enhanced proton sensitivity and proton-induced calcium signals. This alteration is attributed to oligomerization of OGR1 and G2A. The oligomeric potential locates receptors at a specific site, which leads to enhanced proton-induced calcium signals through channels.

  19. Ascorbic acid supplementation partially prevents the delayed reproductive development in juvenile male rats exposed to rosuvastatin since prepuberty.

    PubMed

    Leite, Gabriel Adan Araújo; Figueiredo, Thamiris Moreira; Sanabria, Marciana; Dias, Ana Flávia Mota Gonçalves; Silva, Patrícia Villela E; Martins Junior, Airton da Cunha; Barbosa Junior, Fernando; Kempinas, Wilma De Grava

    2017-10-01

    Dyslipidemias are occurring earlier in the population due to the increase of obesity and bad eating habits. Rosuvastatin inhibits the enzyme HMG-CoA reductase, decreasing total cholesterol. Ascorbic acid is an important antioxidant compound for male reproductive system. This study aimed to evaluate whether ascorbic acid supplementation may prevent the reproductive damage provoked by rosuvastatin administration at prepuberty. Male pups were distributed into six experimental groups that received saline solution 0.9%, 3 or 10mg/kg/day of rosuvastatin, 150mg/day of ascorbic acid, or 150mg/day of ascorbic acid associated with 3 or 10mg/kg/day of rosuvastatin from post-natal day (PND) 23 until PND53. Rosuvastatin-treated groups showed delayed puberty installation, androgen depletion and impairment on testicular and epididymal morphology. Ascorbic acid partially prevented these reproductive damages. In conclusion, rosuvastatin exposure is a probable risk to reproductive development and ascorbic acid supplementation may be useful to prevent the reproductive impairment of rosuvastatin exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Calcium Regulates FGF-23 Expression in Bone

    PubMed Central

    David, Valentin; Dai, Bing; Martin, Aline; Huang, Jinsong; Han, Xiaobin

    2013-01-01

    Calcium has recently been shown to regulate fibroblast growth factor 23 (FGF-23), a bone-derived phosphate and vitamin D-regulating hormone. To better understand the regulation of FGF-23 by calcium, phosphorus, 1,25 dihydroxyvitamin D3 [1,25(OH)2D], and PTH, we examined FGF-23 expression under basal conditions and in response to PTH, doxercalciferol, or high-calcium diet treatment in Gcm2−/− and Cyp27b1−/− mutant mice. Gcm2−/− mice exhibited low serum PTH and 1,25(OH)2D concentrations, hypocalcemia, and hyperphosphatemia, whereas Cyp27b1−/− mice had high PTH, undetectable 1,25(OH)2D, hypocalcemia, and hypophosphatemia. Serum FGF-23 levels were decreased in both mutant models. Doxercalciferol administration increased serum FGF-23 levels in both mutant models. PTH administration to Gcm2−/− mice also increased serum FGF-23 levels, in association with an increase in both 1,25(OH)2D and calcium concentrations. Multiple regression analysis of pooled data indicated that changes in FGF-23 were positively correlated with serum calcium and 1,25(OH)2D but not related to changes in serum phosphate concentrations. A high-calcium diet also increased serum FGF-23 concentrations in Cyp27b1−/− mice in the absence of 1,25(OH)2D and in Gcm2−/− mice with low PTH. The addition of calcium to the culture media also stimulated FGF-23 message expression in MC3T3-E1 osteoblasts. In addition, FGF-23 promoter activity in cultured osteoblasts was inhibited by the L-calcium-channel inhibitor nifedipine and stimulated by calcium ionophores. The effects of chronic low calcium to prevent 1,25(OH)2D and PTH stimulation of FGF-23 in these mutant mouse models suggest that suppression of FGF-23 plays an important physiological adaptive response to hypocalcemia. PMID:24140714

  1. Once-yearly zoledronic acid in hip fracture prevention

    PubMed Central

    Demontiero, Oddom; Duque, Gustavo

    2009-01-01

    Osteoporosis is an escalating global problem. Hip fractures, the most catastrophic complication of osteoporosis, continue to cause significant mortality and morbidity despite increasing availability of effective preventative agents. Among these agents, oral bisphosphonates have been the first choice for the treatment and prevention of osteoporotic fractures. However, the use of oral bisphosphonates, especially in the older population, has been limited by their side effects and method of administration thus compromising their persistent use. The resultant low adherence by patients has undermined their full potential and has been associated with an increase in the incidence of fragility fractures. Recently, annual intravenous zoledronic acid (ZOL) has been approved for osteoporosis. Randomized controlled trials have demonstrated ZOL to be safe, have good tolerability and produce significant effect on bone mass and microarchitecture. Adherence has also been shown to be better with ZOL. Furthermore two large trials firmly demonstrated significant anti-osteoporotic effect (∼59% relative risk reduction of hip fractures) and mortality benefit (28% reduction in mortality) of ZOL in older persons with recent hip fractures. In this review, we report the current evidence on the use of ZOL for the prevention of hip fractures in the elderly. We also report the pharmacological characteristics and the advantages and disadvantages of ZOL in this particular group. PMID:19503777

  2. Vitamin D-mediated calcium absorption in patients with clinically stable Crohn's disease: a pilot study

    USDA-ARS?s Scientific Manuscript database

    Vitamin D is the critical hormone for intestinal absorption of calcium. Optimal calcium absorption is important for proper mineralization of bone in the prevention of osteoporosis and osteoporotic fractures, among other important functions. Diseases associated with gut inflammation, such as Crohn's ...

  3. Comparative bladder tumor promoting activity of sodium saccharin, sodium ascorbate, related acids, and calcium salts in rats.

    PubMed

    Cohen, S M; Ellwein, L B; Okamura, T; Masui, T; Johansson, S L; Smith, R A; Wehner, J M; Khachab, M; Chappel, C I; Schoenig, G P

    1991-04-01

    Sodium saccharin and sodium ascorbate are known to promote urinary bladder carcinogenesis in rats following initiation with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) or N-butyl-N-(4-hydroxybutyl) nitrosamine. Sodium salts of other organic acids have also been shown to be bladder tumor promoters. In addition, these substances increase urothelial proliferation in short term assays in rats when fed at high doses. When they have been tested, the acid forms of these salts are without either promoting or cell proliferative inducing activity. The following experiment was designed to compare the tumor promoting activity of various forms of saccharin and to evaluate the role in promotion of urinary sodium, calcium, and pH as well as other factors. Twenty groups of 40 male F344 rats, 5 weeks of age, were fed either FANFT or control diet during a 6-week initiation phase followed by feeding of a test compound for 72 weeks in the second phase. The chemicals were administered to the first 18 groups in Agway Prolab 3200 diet and the last 2 groups were fed NIH-07 diet. The treatments were as follows: (a) FANFT----5% sodium saccharin (NaS); (b) FANFT----3% NaS; (c) FANFT----5.2% calcium saccharin (CaS); (d) FANFT----3.12% CaS; (e) FANFT----4.21% acid saccharin (S); (f) FANFT----2.53% S; (g) FANFT----5% sodium ascorbate; (h) FANFT----4.44% ascorbic acid; (i) FANFT----5% NaS plus 1.15% CaCO3; (j) FANFT----5.2% CaS plus 1.34% NaCl; (k) FANFT----5% NaS plus 1.23% NH4Cl; (l) FANFT----1.15% CaCO3; (m) FANFT----1.34% NaCl; (n) FANFT----control; (o) control----5% NaS; (p) control----5.2% CaS; (q) control----4.21% S; (r) Control----control; (s) FANFT----5% NaS (NIH-07 diet); (t) FANFT----control (NIH-07 diet). NaS, CaS and S without prior FANFT administration were without tumorigenic activity. NaS was found to have tumor promoting activity, showing a positive response at the 5 and 3% dose levels, with significantly greater activity at the higher dose. CaS had slight tumor

  4. Geloina coaxans shell as calcium source on synthesis hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Yanti, P. H.; Kamiah, A.

    2018-04-01

    Geloina coaxans shell (GCS) is one of mullusc shell mainly composed by calcium carbonate. In this work, calcium carbonate has been converted to calcium oxide by calcination at 1000°C for 12 hours. The calcined of geloina coaxans shell were treated with HNO3 to produce Ca(NO3)2 as calcium source on synthesis hydroxyapatite. Orthophosphoric acid (H3PO4) was used as phosphate donor. Reaction of Ca/P has been done by precipitation method at molar ratio of precursors of 1.67 and pH adjusted at 10 using NH4OH. The XRD result revealed that hydoxyapatite can be prepared at 3 M of HNO3 and stirring time for 240 minutes. Specific band of hydroxyapatite such as PO4 and OH observed using FTIR instrument. Analysis of crystal size using Schererr equation proved nanosize of powder hydroxyapatite can be produced.

  5. Nutritional rickets: pathogenesis and prevention.

    PubMed

    Pettifor, John M

    2013-06-01

    Nutritional rickets remains a public health concern in many areas of the world despite cheap and effective means of preventing the disease. The roles of vitamin D deficiency, low dietary calcium intakes and the interrelationships between the two in the pathogenesis of the disease are discussed. It is now recognized that vitamin D deficiency in the pregnant and lactating mother predisposes to the development of rickets in the breastfed infant, and that cultural and social factors are important in the pathogenesis of the disease during the adolescent growth spurt. Prevention of rickets is dependent on the awareness of the medical profession and the general public of the need to ensure adequate intakes of vitamin D in at-risk populations, and of the importance of increasing dietary intakes of calcium using locally available and inexpensive foods in communities in which dietary calcium deficiency rickets is prevalent.

  6. System for agitating the acid in a lead-acid battery

    DOEpatents

    Weintraub, Alvin; MacCormack, Robert S.

    1987-01-01

    A system and method for agitating the acid in a large lead-sulfuric acid storage battery of the calcium type. An air-lift is utilized to provide the agitation. The air fed to the air-lift is humidified prior to being delivered to the air-lift.

  7. PREVENTION OF SCALE FORMATION IN URANIUM SOLVENT EXTRACTOR

    DOEpatents

    Delaplaine, J.W.

    1957-11-01

    A method for preventing the formation of scale in uranium solvent extraction apparatus is presented. The scale, consisting chiefly of precipitated silica and the sulfates uf calcium and lead, may be prevented by a combination of measures, chiefly by prior heating and agitation to crystallize and remove silica, and by a maintenance of uranyl nitrate concentration in the feed and extractant above certain levels to increase the solubility of the calcium and lead sulfates.

  8. Characterization and N-terminal sequencing of a calcium binding protein from the calcareous concretion organic matrix of the terrestrial crustacean Orchestia cavimana.

    PubMed

    Luquet, G; Testenière, O; Graf, F

    1996-04-16

    We extracted proteins from the organic matrix of calcareous concretions, which represents the calcium storage form in a terrestrial crustacean. Electrophoretic analyses of water-soluble organic-matrix proteinaceous components revealed 11 polypeptides, 6 of which are probably glycosylated. Among the unglycosylated proteins, we characterized a 23 kDa polypeptide, with an isoelectric point of 5.5, which is able to bind calcium. Its N-terminal sequence is rich in acidic amino acids (essentially aspartic acid). All these characteristics suggest its involvement in the calcium precipitation process within the successive layers of the organic matrix.

  9. Effect of Microgravity on Bone Tissue and Calcium Metabolism

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TA4 includes short reports concerning: (1) Human Bone Tissue Changes after Long-Term Space Flight: Phenomenology and Possible Mechanics; (2) Prediction of Femoral Neck Bone Mineral Density Change in Space; (3) Dietary Calcium in Space; (4) Calcium Metabolism During Extended-Duration Space Flight; (5) External Impact Loads on the Lower Extremity During Jumping in Simulated Microgravity and the Relationship to Internal Bone Strain; and (6) Bone Loss During Long Term Space Flight is Prevented by the Application of a Short Term Impulsive Mechanical Stimulus.

  10. The possible mechanism of Parkinson's disease progressive damage and the preventive effect of GM1 in the rat model induced by 6-hydroxydopamine.

    PubMed

    Xu, Renshi; Zhou, Yiyi; Fang, Xin; Lu, Yi; Li, Jiao; Zhang, Jie; Deng, Xia; Li, Shujuan

    2014-12-10

    The progressive pathogenesis and prevention of Parkinson's disease (PD) remains unknown at present. Therefore, the present study aimed to investigate the possible progressive pathogenesis and prevention of PD. Our study investigated the content of glutamate, mitochondria calcium, calmodulin, malonaldehyde and trace elements in striatum, cerebral cortex and hippocampus tissues; and the expression of bcl-2, bax and neuronal nitric oxide synthase (nNOS) in substantia nigra and striatum; and the change of apomorphine induced rotation behavior; and the treatmental effect of monosialotetrahexosylganglioside (GM1) intraperitoneal administration for 14 days in a PD rat model induced by 6-hydroxydopamine. The results revealed that the content of glutamate significantly decreased, and that of mitochondria calcium, calmodulin, malonaldehyde and ferrum significantly increased in striatum, cerebral cortex and hippocampus tissues; the content of magnesium significantly decreased, and that of cuprum and zinc significantly increased in cerebral cortex; the expression of bcl-2 significantly decreased, and that of bax and nNOS significantly increased in substantia nigra and striatum in PD rat. GM1 can partially improve the apomorphine induced rotation behavior and changes of glutamate, mitochondria calcium, calmodulin content in striatum of PD rat. Data suggested that dysfunction of excitatory amino acids neurotransmitter, calcium homeostasis disorder, abnormal metabolism of oxygen free radicals, abnormal trace elements distribution and/or deposition and excessive apoptosis participated in the progressive process of PD, and that GM1 could partially prevent the progressive damage. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Is intravesical instillation of hyaluronic acid and chondroitin sulfate useful in preventing recurrent bacterial cystitis? A multicenter case control analysis.

    PubMed

    Gugliotta, Giorgio; Calagna, Gloria; Adile, Giorgio; Polito, Salvatore; Saitta, Salvatore; Speciale, Patrizia; Palomba, Stefano; Perino, Antonino; Granese, Roberta; Adile, Biagio

    2015-10-01

    Urinary tract infections (UTIs) are common in the female population and, over a lifetime, about half of women have at least one episode of UTI requiring antibiotic therapy. The aim of the current study was to compare two different strategies for preventing recurrent bacterial cystitis: intravesical instillation of hyaluronic acid (HA) plus chondroitin sulfate (CS), and antibiotic prophylaxis with sulfamethoxazole plus trimethoprim. This was a retrospective review of two different cohorts of women affected by recurrent bacterial cystitis. Cases (experimental group) were women who received intravesical instillations of a sterile solution of high concentration of HA + CS in 50 mL water with calcium chloride every week during the 1(st) month and then once monthly for 4 months. The control group included women who received traditional therapy for recurrent cystitis based on daily antibiotic prophylaxis using sulfamethoxazole 200 mg plus trimethoprim 40 mg for 6 weeks. Ninety-eight and 76 patients were treated with experimental and control treatments, respectively. At 12 months after treatment, 69 and 109 UTIs were detected in the experimental and control groups, respectively. The proportion of patients free from UTIs was significantly higher in the experimental than in the control group (36.7% vs. 21.0%; p = 0.03). Experimental treatment was well tolerated and none of the patients stopped it. The intravesical instillation of HA + CS is more effective than long-term antibiotic prophylaxis for preventing recurrent bacterial cystitis. Copyright © 2015. Published by Elsevier B.V.

  12. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  13. Milk composition, milk fatty acid profile, digestion, and ruminal fermentation in dairy cows fed whole flaxseed and calcium salts of flaxseed oil.

    PubMed

    Côrtes, C; da Silva-Kazama, D C; Kazama, R; Gagnon, N; Benchaar, C; Santos, G T D; Zeoula, L M; Petit, H V

    2010-07-01

    Four ruminally lactating Holstein cows averaging 602+/-25 kg of body weight and 64+/-6 d in milk at the beginning of the experiment were randomly assigned to a 4 x 4 Latin square design to determine the effects of feeding whole flaxseed and calcium salts of flaxseed oil on dry matter intake, digestibility, ruminal fermentation, milk production and composition, and milk fatty acid profile. The treatments were a control with no flaxseed products (CON) or a diet (on a dry matter basis) of 4.2% whole flaxseed (FLA), 1.9% calcium salts of flaxseed oil (SAL), or 2.3% whole flaxseed and 0.8% calcium salts of flaxseed oil (MIX). The 4 isonitrogenous and isoenergetic diets were fed for ad libitum intake. Experimental periods consisted of 21 d of diet adaptation and 7 d of data collection and sampling. Dry matter intake, digestibility, milk production, and milk concentrations of protein, lactose, urea N, and total solids did not differ among treatments. Ruminal pH was reduced for cows fed the CON diet compared with those fed the SAL diet. Propionate proportion was higher in ruminal fluid of cows fed CON than in that of those fed SAL, and cows fed the SAL and CON diets had ruminal propionate concentrations similar to those of cows fed the FLA and MIX diets. Butyrate concentration was numerically higher for cows fed the SAL diet compared with those fed the FLA diet. Milk fat concentration was lower for cows fed SAL than for those fed CON, and there was no difference between cows fed CON and those fed FLA and MIX. Milk yields of protein, fat, lactose, and total solids were similar among treatments. Concentrations of cis-9 18:1 and of intermediates of ruminal biohydrogenation of fatty acids such as trans-9 18:1 were higher in milk fat of cows fed SAL and MIX than for those fed the CON diet. Concentration of rumenic acid (cis-9, trans-11 18:2) in milk fat was increased by 63% when feeding SAL compared with FLA. Concentration of alpha-linolenic acid was higher in milk fat of cows

  14. Effects of calcium supplementation on body weight and adiposity in overweight and obese adults: a randomized trial.

    PubMed

    Yanovski, Jack A; Parikh, Shamik J; Yanoff, Lisa B; Denkinger, Blakeley I; Calis, Karim A; Reynolds, James C; Sebring, Nancy G; McHugh, Teresa

    2009-06-16

    Some data suggest that increasing calcium intake may help prevent weight gain. To test the hypothesis that calcium supplementation can prevent weight gain in persons who are overweight or obese. Randomized, placebo-controlled trial. Randomization was computer-generated, and allocation was assigned by pharmacy personnel who prepared intervention and placebo capsules. Participants, providers, and those who assessed outcomes were blinded to study group assignment. Single research center. 340 overweight (body mass index [BMI], 25 to <30 kg/m(2)) and obese (BMI > or =30 kg/m(2)) adults (mean age, 38.8 years [SD, 10.5]). Calcium carbonate (elemental calcium, 1500 mg/d) (n = 170) or placebo (n = 170) with meals for 2 years. Changes in body weight and fat mass (primary outcomes). Seventy-five percent of participants completed the trial (78% received calcium; 73% received placebo). There were no statistically or clinically significant differences between the calcium and placebo groups in change in body weight (difference, 0.02 kg [95% CI, -1.64 to 1.69 kg]; P = 0.98), BMI (difference, 0.32 kg/m(2) [CI, -0.41 to 1.02 kg/m(2)]; P = 0.39), or body fat mass (difference, 0.39 kg [CI, -1.04 to 1.92 kg]; P = 0.55). Parathyroid hormone concentrations decreased in the calcium group compared with the placebo group (difference, -0.71 pmol/L [CI, -1.28 to -0.13 pmol/L]). The study took place at a research center, and its sample was mostly women. Dietary supplementation with elemental calcium, 1500 mg/d, for 2 years had no statistically or clinically significant effects on weight in overweight and obese adults. Calcium supplementation is unlikely to have clinically significant efficacy as a preventive measure against weight gain in such patients.

  15. Calcium sensitive ring-like oligomers formed by synaptotagmin

    PubMed Central

    Wang, Jing; Bello, Oscar; Auclair, Sarah M.; Wang, Jing; Coleman, Jeff; Pincet, Frederic; Krishnakumar, Shyam S.; Sindelar, Charles V.; Rothman, James E.

    2014-01-01

    The synaptic vesicle protein synaptotagmin-1 (SYT) is required to couple calcium influx to the membrane fusion machinery. However, the structural mechanism underlying this process is unclear. Here we report an unexpected circular arrangement (ring) of SYT’s cytosolic domain (C2AB) formed on lipid monolayers in the absence of free calcium ions as revealed by electron microscopy. Rings vary in diameter from 18–43 nm, corresponding to 11–26 molecules of SYT. Continuous stacking of the SYT rings occasionally converts both lipid monolayers and bilayers into protein-coated tubes. Helical reconstruction of the SYT tubes shows that one of the C2 domains (most likely C2B, based on its biochemical properties) interacts with the membrane and is involved in ring formation, and the other C2 domain points radially outward. SYT rings are disrupted rapidly by physiological concentrations of free calcium but not by magnesium. Assuming that calcium-free SYT rings are physiologically relevant, these results suggest a simple and novel mechanism by which SYT regulates neurotransmitter release: The ring acts as a spacer to prevent the completion of the soluble N-ethylmaleimide–sensitive factor activating protein receptor (SNARE) complex assembly, thereby clamping fusion in the absence of calcium. When the ring disassembles in the presence of calcium, fusion proceeds unimpeded. PMID:25201968

  16. Ferulic acid prevents liver injury and increases the anti-tumor effect of diosbulbin B in vivo *

    PubMed Central

    Wang, Jun-ming; Sheng, Yu-chen; Ji, Li-li; Wang, Zheng-tao

    2014-01-01

    The present study is designed to investigate the protection by ferulic acid against the hepatotoxicity induced by diosbulbin B and its possible mechanism, and further observe whether ferulic acid augments diosbulbin B-induced anti-tumor activity. The results show that ferulic acid decreases diosbulbin B-increased serum alanine transaminase/aspartate transaminase (ALT/AST) levels. Ferulic acid also decreases lipid peroxide (LPO) levels which are elevated in diosbulbin B-treated mice. Histological evaluation of the liver demonstrates hydropic degeneration in diosbulbin B-treated mice, while ferulic acid reverses this injury. Moreover, the activities of copper- and zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) are decreased in the livers of diosbulbin B-treated mice, while ferulic acid reverses these decreases. Further results demonstrate that the mRNA expressions of CuZn-SOD and CAT in diosbulbin B-treated mouse liver are significantly decreased, while ferulic acid prevents this decrease. In addition, ferulic acid also augments diosbulbin B-induced tumor growth inhibition compared with diosbulbin B alone. Taken together, the present study shows that ferulic acid prevents diosbulbin B-induced liver injury via ameliorating diosbulbin B-induced liver oxidative stress injury and augments diosbulbin B-induced anti-tumor activity. PMID:24903991

  17. Cardiac Society of Australia and New Zealand Position Statement: Coronary Artery Calcium Scoring.

    PubMed

    Liew, Gary; Chow, Clara; van Pelt, Niels; Younger, John; Jelinek, Michael; Chan, Jonathan; Hamilton-Craig, Christian

    2017-12-01

    Coronary Artery Calcium Scoring (CAC) is a non-invasive quantitation of coronary artery calcification using computed tomography (CT). It is a marker of atherosclerotic plaque burden and an independent predictor of future myocardial infarction and mortality. Coronary Artery Calcium Scoring provides incremental risk information beyond traditional risk calculators (eg. Framingham Risk Score). Its use for risk stratification is confined to primary prevention of cardiovascular events, and can be considered as "individualised coronary risk scoring" for those not considered to be of high or low risk. Medical practitioners should carefully counsel patients prior to CAC. Coronary Artery Calcium Scoring should only be undertaken if an alteration in therapy including embarking on pharmacotherapy is being considered based on the test result. Patient Groups to Consider Coronary Calcium Scoring: Patient Groups in Whom Coronary Calcium Scoring Should Not be Considered: Coronary Artery Calcium Scoring is not recommended for patients who are: Interpretation of CAC CAC=0 A zero score confers a very low risk of death, <1% at 10 years. CAC=1-100 Low risk, <10% CAC=101-400 Intermediate risk, 10-20% CAC=101-400 & >75th centile. Moderately high risk, 15-20% CAC >400 High risk, >20% Management Recommendations Based on CAC Optimal diet and lifestyle measures are encouraged in all risk groups and form the basis of primary prevention strategies. Patients with moderately-high or high risk based on CAC score are recommended to receive preventative medical therapy such as aspirin and statins. The evidence for pharmacotherapy is less robust in patients at intermediate levels of CAC 100-400, with modest benefit for aspirin use; though statins may be reasonable if they are above 75th centile. Aspirin and statins are generally not recommended in patients with CAC <100. Repeat CAC Testing In patients with a CAC of 0, a repeat CAC may be considered in 5 years but not sooner. In patients with positive

  18. The SARS Coronavirus 3a protein binds calcium in its cytoplasmic domain.

    PubMed

    Minakshi, Rinki; Padhan, Kartika; Rehman, Safikur; Hassan, Md Imtaiyaz; Ahmad, Faizan

    2014-10-13

    The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) is a positive stranded RNA virus with ∼30kb genome. Among all open reading frames (orfs) of this virus, the orf3a is the largest, and encodes a protein of 274 amino acids, named as 3a protein. Sequence analysis suggests that the orf3a aligned to one calcium pump present in Plasmodium falciparum and the enzyme glutamine synthetase found in Leptospira interrogans. This sequence similarity was found to be limited only to amino acid residues 209-264 which form the cytoplasmic domain of the orf3a. Furthermore, this region was predicted to be involved in the calcium binding. Owing to this hypothesis, we were driven to establish its calcium binding property in vitro. Here, we expressed and purified the cytoplasmic domain of the 3a protein, called Cyto3a, as a recombinant His-tagged protein in the E. coli. The calcium binding nature was established by performing various staining methods such as ruthenium red and stains-all. (45)Ca overlay method was also done to further support the data. Since the 3a protein forms ion channels, we were interested to see any conformational changes occurring in the Cyot3a upon calcium binding, using fluorescence spectroscopy and circular dichroism. These studies clearly indicate a significant change in the conformation of the Cyto3a protein after binding with calcium. Our results strongly suggest that the cytoplasmic domain of the 3a protein of SARS-CoV binds calcium in vitro, causing a change in protein conformation. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Effect of the calcium silicate-based sealer removal protocols and time-point of acid etching on the dentin adhesive interface.

    PubMed

    Morais, Jéssika Mayhara Pereira; Victorino, Keli Regina; Escalante-Otárola, Wilfredo Gustavo; Jordão-Basso, Keren Cristina Fagundes; Palma-Dibb, Regina Guenka; Kuga, Milton Carlos

    2018-06-15

    The aim of the study was to evaluate the effects when acid etching on the dentin surface was immediately performed (I) or 7 days (D) after calcium silicate-based sealer (MTA Fillapex) removal, using 95% ethanol (E) or xylol (X). First study, 60 bovine incisor dentin specimens were impregnated with sealer and divided into six groups (n = 10): (EI), E + I; (XI), X + I; (ED), E + D; (XD), X + D, (UN), untreated and (MR), mechanical removal of sealer. Scanning electron microscopy (SEM) images (500×) were obtained from each specimen and scores assessed the sealer residues persistence. Second study, 60 specimens were similarly treated; however, the specimens were restored with composite resin after the removal protocols. Hybrid layer formation was evaluated using confocal laser microscopy (1,024×). Third study, 60 specimens were similarly obtained and subjected to micro-shear test to evaluate the effects of removal protocols on the bond strength of etch-and- rinse adhesive system to dentin. XI showed the highest persistence of sealer residues (p < .05), similar to MR (p > .05). EI showed the greatest hybrid layer extension, except in relation to UN (p < .05). XI and MR presented the lowest bond strength adhesive system to dentin (p < .05). Acid etching immediately after calcium silicate-based endodontic sealer removal using xylol presented the highest residues persistence and negatively affected the adhesive interface between dentin and etch-and-rinse adhesive system. © 2018 Wiley Periodicals, Inc.

  20. Docosahexaenoic acid prevents trans-10, cis-12 conjugated linoleic acid-induced non-alcoholic fatty liver disease in mice by altering expression of hepatic genes regulating fatty acid synthesis and oxidation

    USDA-ARS?s Scientific Manuscript database

    Background: Concomitant supplementation with docosahexaenoic acid (22:6 n-3; DHA) prevented t10, c12- conjugated linoleic acid (CLA)-induced non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Effective dose of DHA and mechanisms involved are poorly understood. Methods: We examined abi...

  1. Patient adviser banking on strong bones for life: do you need calcium supplements?

    PubMed

    Harmon, Kimberly G

    2002-03-01

    Calcium is important for building strong teeth and bones and for preventing osteoporosis. It is especially important that adolescents and young adults get adequate amounts of calcium. In women, bone density can increase until around age 30. After that, bone mass is maintained or lost at a slow rate until menopause, when the rate of bone loss increases.

  2. Determination of Calcium in Dietary Supplements: Statistical Comparison of Methods in the Analytical Laboratory

    ERIC Educational Resources Information Center

    Garvey, Sarah L.; Shahmohammadi, Golbon; McLain, Derek R.; Dietz, Mark L.

    2015-01-01

    A laboratory experiment is described in which students compare two methods for the determination of the calcium content of commercial dietary supplement tablets. In a two-week sequence, the sample tablets are first analyzed via complexometric titration with ethylenediaminetetraacetic acid and then, following ion exchange of the calcium ion present…

  3. Vitamin D and intestinal calcium transport after bariatric surgery.

    PubMed

    Schafer, Anne L

    2017-10-01

    Bariatric surgery is a highly effective treatment for obesity, but it may have detrimental effects on the skeleton. Skeletal effects are multifactorial but mediated in part by nutrient malabsorption. While there is increasing interest in non-nutritional mechanisms such as changes in fat-derived and gut-derived hormones, nutritional factors are modifiable and thus represent potential opportunities to prevent and treat skeletal complications. This review begins with a discussion of normal intestinal calcium transport, including recent advances in our understanding of its regulation by vitamin D, and areas of continued uncertainty. Human and animal studies of vitamin D and intestinal calcium transport after bariatric surgery are then summarized. In humans, even with optimized 25-hydroxyvitamin D levels and recommended calcium intake, fractional calcium absorption decreased dramatically after Roux-en-Y gastric bypass (RYGB). In rats, intestinal calcium absorption was lower after RYGB than after sham surgery, despite elevated 1,25-dihyroxyvitamin D levels and intestinal gene expression evidence of vitamin D responsiveness. Such studies have the potential to shed new light on the physiology of vitamin D and intestinal calcium transport. Moreover, understanding the effects of bariatric surgery on these processes may improve the clinical care of bariatric surgery patients. Published by Elsevier Ltd.

  4. Synthesis and characterization of amino acid-functionalized calcium phosphate nanoparticles for siRNA delivery.

    PubMed

    Bakan, Feray; Kara, Goknur; Cokol Cakmak, Melike; Cokol, Murat; Denkbas, Emir Baki

    2017-10-01

    Small interfering RNAs (siRNA) are short nucleic acid fragments of about 20-27 nucleotides, which can inhibit the expression of specific genes. siRNA based RNAi technology has emerged as a promising method for the treatment of a variety of diseases. However, a major limitation in the therapeutic use of siRNA is its rapid degradation in plasma and cellular cytoplasm, resulting in short half-life. In addition, as siRNA molecules cannot penetrate into the cell efficiently, it is required to use a carrier system for its delivery. In this work, chemically and morphologically different calcium phosphate (CaP) nanoparticles, including spherical-like hydroxyapatite (HA-s), needle-like hydroxyapatite (HA-n) and calcium deficient hydroxyapatite (CDHA) nanoparticles were synthesized by the sol-gel technique and the effects of particle characteristics on the binding capacity of siRNA were investigated. In order to enhance the gene loading efficiency, the nanoparticles were functionalized with arginine and the morphological and their structural characteristics were analyzed. The addition of arginine did not significantly change the particle sizes; however, it provided a significantly increased binding of siRNA for all types of CaP nanoparticles, as revealed by spectrophotometric measurements analysis. Arginine functionalized HA-n nanoparticles showed the best binding behavior with siRNA among the other nanoparticles due to its high, positive zeta potential (+18.8mV) and high surface area of Ca ++ rich "c" plane. MTT cytotoxicity assays demonstrated that all the nanoparticles tested herein were biocompatible. Our results suggest that high siRNA entrapment in each of the three modified non-toxic CaP nanoparticles make them promising candidates as a non-viral vector for delivering therapeutic siRNA molecules to treat cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. [Aging and homeostasis. Management of disorders in bone and calcium metabolism associated with ageing.

    PubMed

    Takeuchi, Yasuhiro

    Disorders in bone and calcium metabolism associated with aging are based on secondary hyperparathyroidism due to impaired intestinal calcium absorption caused by insufficient vitamin D actions and augmented bone resorption due to sex hormone deficiency. Both of them are involved in the development of osteoporosis that increases risk of fractures. Therefore, the most important thing for management of disorders in bone and calcium metabolism associated with aging is to prevent fractures with appropriate drugs for osteoporosis.

  6. Ultracytochemical visualization of calcium distribution in heart cells and erythrocytes of zebrafish Danio rerio.

    PubMed

    Niksirat, Hamid; Steinbach, Christoph

    2018-05-24

    Detection of patterns of subcellular calcium distribution in the cardiovascular system can contribute to understanding its role in cardiac and blood function. The present study localized calcium in heart atrium, ventricle, and bulbus arteriosus as well as in erythrocytes of zebrafish Danio rerio using an oxalate-pyroantimonate technique combined with transmission electron microscopy. Intracellular calcium stores were detected in caveolae, mitochondria, and the nuclei of several zebrafish cardiac cell types. Melanin pigmentation containing calcium stores was detected in the pericardial cavity. Melanin might be an extracellular source of calcium for heart beating and/or a lubricant to prevent friction during beating process. Calcium deposits were also detected in the plasma membrane, cytoplasm and nucleus of erythrocytes as well as in blood plasma. Possible exchange of calcium between erythrocytes and blood plasma was observed. Interactions of such calcium stores and possible contribution of extracellular calcium stores such as melanin pigmentation to supply calcium for vital functions of heart cells should be addressed in future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. RapA2 Is a Calcium-binding Lectin Composed of Two Highly Conserved Cadherin-like Domains That Specifically Recognize Rhizobium leguminosarum Acidic Exopolysaccharides*

    PubMed Central

    Abdian, Patricia L.; Caramelo, Julio J.; Ausmees, Nora; Zorreguieta, Angeles

    2013-01-01

    In silico analyses have revealed a conserved protein domain (CHDL) widely present in bacteria that has significant structural similarity to eukaryotic cadherins. A CHDL domain was shown to be present in RapA, a protein that is involved in autoaggregation of Rhizobium cells, biofilm formation, and adhesion to plant roots as shown by us and others. Structural similarity to cadherins suggested calcium-dependent oligomerization of CHDL domains as a mechanistic basis for RapA action. Here we show by circular dichroism spectroscopy, light scattering, isothermal titration calorimetry, and other methods that RapA2 from Rhizobium leguminosarum indeed exhibits a cadherin-like β-sheet conformation and that its proper folding and stability are dependent on the binding of one calcium ion per protein molecule. By further in silico analysis we also reveal that RapA2 consists of two CHDL domains and expand the range of CHDL-containing proteins in bacteria and archaea. However, light scattering assays at various concentrations of added calcium revealed that RapA2 formed neither homo-oligomers nor hetero-oligomers with RapB (a distinct CHDL protein), indicating that RapA2 does not mediate cellular interactions through a cadherin-like mechanism. Instead, we demonstrate that RapA2 interacts specifically with the acidic exopolysaccharides (EPSs) produced by R. leguminosarum in a calcium-dependent manner, sustaining a role of these proteins in the development of the biofilm matrix made of EPS. Because EPS binding by RapA2 can only be attributed to its two CHDL domains, we propose that RapA2 is a calcium-dependent lectin and that CHDL domains in various bacterial and archaeal proteins confer carbohydrate binding activity to these proteins. PMID:23235153

  8. Distance-dependent gradient in NMDAR-driven spine calcium signals along tapering dendrites

    PubMed Central

    Walker, Alison S.; Grillo, Federico; Jackson, Rachel E.; Rigby, Mark; Lowe, Andrew S.; Vizcay-Barrena, Gema; Fleck, Roland A.; Burrone, Juan

    2017-01-01

    Neurons receive a multitude of synaptic inputs along their dendritic arbor, but how this highly heterogeneous population of synaptic compartments is spatially organized remains unclear. By measuring N-methyl-d-aspartic acid receptor (NMDAR)-driven calcium responses in single spines, we provide a spatial map of synaptic calcium signals along dendritic arbors of hippocampal neurons and relate this to measures of synapse structure. We find that quantal NMDAR calcium signals increase in amplitude as they approach a thinning dendritic tip end. Based on a compartmental model of spine calcium dynamics, we propose that this biased distribution in calcium signals is governed by a gradual, distance-dependent decline in spine size, which we visualized using serial block-face scanning electron microscopy. Our data describe a cell-autonomous feature of principal neurons, where tapering dendrites show an inverse distribution of spine size and NMDAR-driven calcium signals along dendritic trees, with important implications for synaptic plasticity rules and spine function. PMID:28209776

  9. Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

    PubMed

    Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

    2015-01-01

    Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

  10. Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells.

    PubMed

    Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

    2016-05-06

    Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of -22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration.

  11. Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells

    PubMed Central

    Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

    2016-01-01

    Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of −22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration. PMID:27164090

  12. Ent-7α-acetoxytrachyloban-18-oic acid and ent-7α-hydroxytrachyloban-18-oic acid from Xylopia langsdorfiana A. St-Hil. & Tul. modulate K(+) and Ca(2+) channels to reduce cytosolic calcium concentration on guinea pig ileum.

    PubMed

    Santos, Rosimeire F; Martins, Italo R R; Travassos, Rafael A; Tavares, Josean F; Silva, Marcelo S; Paredes-Gamero, Edgar J; Ferreira, Alice T; Nouailhetas, Viviane L A; Aboulafia, Jeannine; Rigoni, Vera L S; da Silva, Bagnólia A

    2012-03-05

    In this study we investigated the mechanism underlying the spasmolytic action of ent-7α-acetoxytrachyloban-18-oic acid (trachylobane-360) and ent-7α-hydroxytrachyloban-18-oic acid (trachylobane-318), diterpenes obtained from Xylopia langsdorfiana, on guinea pig ileum. Both compounds inhibited histamine-induced cumulative contractions (slope=3.5±0.9 and 4.4±0.7) that suggests a noncompetitive antagonism to histaminergic receptors. CaCl(2)-induced contractions were nonparallelly and concentration-dependently reduced by both diterpenes, indicating blockade of calcium influx through voltage-dependent calcium channels (Ca(v)). The Ca(v) participation was confirmed since both trachylobanes equipotently relaxed ileum pre-contracted with S-(-)-Bay K8644 (EC(50)=3.5±0.7×10-(5) and 1.1±0.2×10-(5)M) and KCl (EC(50)=5.5±0.3×10-(5) and 1.4±0.2×10-(5)M). K(+) channels participation was confirmed since diterpene-induced relaxation curves were significantly shifted to right in the presence of 5mM tetraethylammonium (TEA(+)) (EC(50)=0.5±0.04×10-(4) and 2.0±0.5×10-(5)M). ATP-sensitive K(+) channel (K(ATP)), voltage activated K(+) channels (K(V)), small conductance calcium-activated K(+) channels (SK(Ca)) or big conductance calcium-activated K(+) channels (BK(Ca)) did not seem to participate of trachylobane-360 spasmolytic action. However trachylobane-318 modulated positively K(ATP), K(V) and SK(Ca) (EC(50)=1.1±0.3×10-(5), 0.7±0.2×10-(5) and 0.7±0.2×10-(5)M), but not BK(Ca). A fluorescence analysis technique confirmed the decrease of cytosolic calcium concentration ([Ca(2+)](c)) induced by both trachylobanes in ileal myocytes. In conclusion, trachylobane-360 and trachylobane-318 induced spasmolytic activity by K(+) channel positive modulation and Ca(2+) channel blockade, which results in [Ca(2+)](c) reduction at cellular level leading to smooth muscle relaxation. Copyright © 2011. Published by Elsevier B.V.

  13. Calcium pathway machinery at fertilization in echinoderms

    PubMed Central

    Ramos, Isabela; Wessel, Gary M.

    2016-01-01

    Calcium signaling in cells directs diverse physiological processes. The calcium waves triggered by fertilization is a highly conserved calcium signaling event essential for egg activation, and has been documented in every egg tested. This activity is one of the few highly conserved events of egg activation through the course of evolution. Echinoderm eggs, as well as many other cell types, have three main intracellular Ca2+ mobilizing messengers – IP3, cADPR and NAADP. Both cADPR and NAADP were identified as Ca2+ mobilizing messengers using the sea urchin egg homogenate, and this experimental system, along with the intact urchin and starfish oocyte/egg, continues to be a vital tool for investigating the mechanism of action of calcium signals. While many of the major regulatory steps of the IP3 pathway are well resolved, both cADPR and NAADP remain understudied in terms of our understanding of the fundamental process of egg activation at fertilization. Recently, NAADP has been shown to trigger Ca2+ release from acidic vesicles, separately from the ER, and a new class of calcium channels, the two-pore channels (TPCs), was identified as the likely targets for this messenger. Moreover, it was found that both cADPR and NAADP can be synthesized by the same family of enzymes, the ADP-rybosyl cyclases (ARCs). In this context of increasing amount of information, the potential coupling and functional roles of different messengers, intracellular stores and channels in the formation of the fertilization calcium wave in echinoderms will be critically evaluated. PMID:23218671

  14. Consequences of calcium decline on the embryogenesis and life history of Daphnia magna.

    PubMed

    Giardini, Jamie-Lee; Yan, Norman D; Heyland, Andreas

    2015-07-01

    Ambient calcium is declining in thousands of soft-water lake habitats in temperate regions as a consequence of unsustainable forestry practices, decreased atmospheric calcium deposition and acidic deposition. As their exoskeleton is heavily reinforced with calcium, freshwater crustaceans have a high specific calcium requirement relative to other aquatic organisms. Daphnia, in particular, is an ideal crustacean for investigating the consequences of calcium decline because it is an abundant and important member of freshwater zooplankton communities. Although it has been established that adult and juvenile Daphnia have different tolerances to low ambient calcium as a result of their different life stage-specific calcium requirements, the consequences of declining calcium on embryonic development have never been investigated. Here, we describe the distribution of calcium in embryonic stages of D. magna and introduce a novel and easy to use staging scheme. We tested whether calcium can be traced from mothers to their offspring. Finally, we assessed the fitness consequences of maternal provisioning in limiting calcium environments. We found that while embryos require calcium for their development and moulting, they do not equilibrate with environmental calcium levels. Instead, we were able to trace calcium from mothers to their offspring. Furthermore, our data strongly suggest that females are faced with an allocation trade-off between providing calcium to their offspring and using it for growth and moulting. Together, these data provide novel insights into the consequences of calcium decline for freshwater zooplankton. © 2015. Published by The Company of Biologists Ltd.

  15. Effects of calcium intake on the cardiovascular system in postmenopausal women.

    PubMed

    Challoumas, D; Cobbold, C; Dimitrakakis, G

    2013-11-01

    The use of calcium supplements for the prevention of complications of osteoporosis has significantly increased during the last years. The effects of calcium intake in postmenopausal women on cardiovascular parameters such as blood pressure, serum lipids and cardiovascular events are controversial. Even though transient beneficial effects of calcium supplementation have been reported, especially in women with low dietary calcium intake, their long-term outcomes are inconclusive. Only a very few studies investigating serum lipids in postmenopausal women have been described and these showed significant increases in high-density lipoprotein and high-density lipoprotein to low-density lipoprotein ratio. With regards to cardiovascular events in this population group adverse effects have been reported on the rates of myocardial infarction and stroke with increased calcium intake by some authors, however, others described no effects or even beneficial outcomes. We present a review of the current literature which provides a balanced summary of the possible beneficial and adverse effects of calcium intake in postmenopausal women on cardiovascular parameters. Taking into account the modest effect of calcium supplementation in reducing fracture rates, a reassessment of the role, benefits and adverse effects of calcium supplements should be conducted in postmenopausal women. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Vitamin D and Calcium Supplementation to Prevent Fractures

    MedlinePlus

    ... volunteer panel of national experts in prevention and evidence-based medicine. The Task Force works to improve the health of all Americans by making evidence-based recommendations about clinical ... or preventive medicines. The recommendations apply to people with no signs ...

  17. Complete covalent structure of statherin, a tyrosine-rich acidic peptide which inhibits calcium phosphate precipitation from human parotid saliva.

    PubMed

    Schlesinger, D H; Hay, D I

    1977-03-10

    The complete amino acid sequence of human salivary statherin, a peptide which strongly inhibits precipitation from supersaturated calcium phosphate solutions, and therefore stabilizes supersaturated saliva, has been determined. The NH2-terminal half of this Mr=5380 (43 amino acids) polypeptide was determined by automated Edman degradations (liquid phase) on native statherin. The peptide was digested separately with trypsin, chymotrypsin, and Staphylococcus aureus protease, and the resulting peptides were purified by gel filtration. Manual Edman degradations on purified peptide fragments yielded peptides that completed the amino acid sequence through the penultimate COOH-terminal residue. These analyses, together with carboxypeptidase digestion of native statherin and of peptide fragments of statherin, established the complete sequence of the molecule. The 2 serine residues (positions 2 and 3) in statherin were identified as phosphoserine. The amino acid sequence of human salivary statherin is striking in a number of ways. The NH2-terminal one-third is highly polar and includes three polar dipeptides: H2PO3-Ser-Ser-H2PO3-Arg-Arg-, and Glu-Glu-. The COOH-terminal two-thirds of the molecule is hydrophobic, containing several repeating dipeptides: four of -Gn-Pro-, three of -Tyr-Gln-, two of -Gly-Tyr-, two of-Gln-Tyr-, and two of the tetrapeptide sequence -Pro-Tyr-Gln-Pro-. Unusual cleavage sites in the statherin sequence obtained with chymotrypsin and S. aureus protease were also noted.

  18. Cinnamic Acid and Its Derivatives: Mechanisms for Prevention and Management of Diabetes and Its Complications.

    PubMed

    Adisakwattana, Sirichai

    2017-02-21

    With recent insight into the development of dietary supplements and functional foods, search of effective phytochemical compounds and their mechanisms involved in prevention and management of diabetes and its complications are now being assessed. Cinnamic acid and its derivatives occur naturally in high levels of plant-based foods. Among various biological activities, cinnamic acid and its derivatives are associated with a beneficial influence on diabetes and its complications. The aim of the review is to summarize the potential mechanisms of these compounds for prevention and management of diabetes and its complications. Based on several in vitro studies and animal models, cinnamic acid and its derivatives act on different mechanism of actions, including stimulation of insulin secretion, improvement of pancreatic β-cell functionality, inhibition of hepatic gluconeogenesis, enhanced glucose uptake, increased insulin signaling pathway, delay of carbohydrate digestion and glucose absorption, and inhibition of protein glycation and insulin fibrillation. However, due to the limited intestinal absorption being a result of low bioavailability of cinnamic acid and its derivatives, current improvement efforts with entrapping into solid and liquid particles are highlighted. Further human clinical studies are needed to clarify the effects of cinnamic acid and its derivatives in diabetic patients.

  19. Application of calcium peroxide activated with Fe(II)-EDDS complex in trichloroethylene degradation.

    PubMed

    Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

    2016-10-01

    This study was conducted to assess the application of calcium peroxide (CP) activated with Fe(II) chelated by (S,S)-ethylenediamine-N,N'-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O2(-) promoted HO generation. Cl(-), HCO3(-) and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Calcium regulates glutamate dehydrogenase and poly-γ-glutamic acid synthesis in Bacillus natto.

    PubMed

    Meng, Yonghong; Dong, Guiru; Zhang, Chen; Ren, Yuanyuan; Qu, Yuling; Chen, Weifeng

    2016-04-01

    To study the effect of Ca(2+) on glutamate dehydrogenase (GDH) and its role in poly-γ-glutamic acid (γ-PGA) synthesis in Bacillus natto HSF 1410. When the concentration of Ca(2+) varied from 0 to 0.1 g/l in the growth medium of B. natto HSF 1410, γ-PGA production increased from 6.8 to 9.7 g/l, while GDH specific activity and NH4Cl consumption improved from 183 to 295 U/mg and from 0.65 to 0.77 g/l, respectively. GDH with α-ketoglutarate as substrate primarily used NADPH as coenzyme with a K m of 0.08 mM. GDH was responsible for the synthesis of endogenous glutamate. The specific activity of GDH remained essentially unchanged in the presence of CaCl2 (0.05-0.2 g/l) in vitro. However, the specific activity of GDH and its expression was significantly increased by CaCl2 in vivo. Therefore, the regulation of GDH and PGA synthesis by Ca(2+) is an intracellular process. Calcium regulation may be an effective approach for producing γ-PGA on an industrial scale.

  1. The determination of ultrafiltrable calcium and magnesium in serum.

    PubMed

    Danielson, B G; Pallin, E; Sohtell, M

    1982-01-01

    Ultrafiltrate of human serum was investigated in order to evaluate the serum content of calcium and magnesium. The acid and base concentrations and pH of the serum was altered through titration with HCl- or NaOH-solutions. The Pco2 was varied in the titrated serum using different carbon dioxide tensions. This was performed when serum was filtered in a recycling system. It is shown that the analysis of calcium and magnesium have to be done under anaerobic conditions or at standardized pH and Pco2 situations, as the concentrations vary with both pH and Pco2. The concentration ratio between ultrafiltrate and serum for calcium and magnesium was found to be 0.56 and 0.74 respectively at pH=7.41 and Pco2=40 mmHg.

  2. Activation of Src and release of intracellular calcium by phosphatidic acid during Xenopus laevis fertilization

    PubMed Central

    Bates, Ryan C.; Fees, Colby P.; Holland, William L.; Winger, Courtney C.; Batbayar, Khulan; Ancar, Rachel; Bergren, Todd; Petcoff, Douglas; Stith, Bradley J.

    2014-01-01

    We report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC- γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca]i). Molecular species analysis and mass measurements suggested that sperm activate phospholipase D (PLD) to elevate phosphatidic acid (PA). We now report that PA mass increased 2.7 fold by 1 minute after insemination and inhibition of PA production by two methods inhibited activation of Src and PLCγ, increased [Ca]i and other fertilization events. As compared to 14 other lipids, PA strongly bound Xenopus Src but not PLCγ. Addition of synthetic PA activated egg Src (an action requiring intact lipid rafts) and PLCγ as well as doubling the amount of PLCγ in rafts. In the absence of elevated [Ca]i, PA addition elevated IP3 mass to levels equivalent to that induced by sperm (but twice that achieved by calcium ionophore). Finally, PA induced [Ca]i release that was blocked by an IP3 receptor inhibitor. As only PLD1b message was detected, and Western blotting did not detect PLD2, we suggest that sperm activate PLD1b to elevate PA which then binds to and activates Src leading to PLCγ stimulation, IP3 elevation and [Ca]i release. Due to these and other studies, PA may also play a role in membrane fusion events such as sperm-egg fusion, cortical granule exocytosis, the elevation of phosphatidylinositol 4,5-bisphosphate and the large, late increase in sn 1,2-diacylglycerol in fertilization. PMID:24269904

  3. Activation of Src and release of intracellular calcium by phosphatidic acid during Xenopus laevis fertilization.

    PubMed

    Bates, Ryan C; Fees, Colby P; Holland, William L; Winger, Courtney C; Batbayar, Khulan; Ancar, Rachel; Bergren, Todd; Petcoff, Douglas; Stith, Bradley J

    2014-02-01

    We report a new step in the fertilization in Xenopus laevis which has been found to involve activation of Src tyrosine kinase to stimulate phospholipase C-γ (PLC-γ) which increases inositol 1,4,5-trisphosphate (IP3) to release intracellular calcium ([Ca](i)). Molecular species analysis and mass measurements suggested that sperm activate phospholipase D (PLD) to elevate phosphatidic acid (PA). We now report that PA mass increased 2.7 fold by 1 min after insemination and inhibition of PA production by two methods inhibited activation of Src and PLCγ, increased [Ca](i) and other fertilization events. As compared to 14 other lipids, PA specifically bound Xenopus Src but not PLCγ. Addition of synthetic PA activated egg Src (an action requiring intact lipid rafts) and PLCγ as well as doubling the amount of PLCγ in rafts. In the absence of elevated [Ca](i), PA addition elevated IP3 mass to levels equivalent to that induced by sperm (but twice that achieved by calcium ionophore). Finally, PA induced [Ca](i) release that was blocked by an IP3 receptor inhibitor. As only PLD1b message was detected, and Western blotting did not detect PLD2, we suggest that sperm activate PLD1b to elevate PA which then binds to and activates Src leading to PLCγ stimulation, IP3 elevation and [Ca](i) release. Due to these and other studies, PA may also play a role in membrane fusion events such as sperm-egg fusion, cortical granule exocytosis, the elevation of phosphatidylinositol 4,5-bisphosphate and the large, late increase in sn 1,2-diacylglycerol in fertilization. © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  4. The old is new again: asparagine oxidation in calcium-dependent antibiotic biosynthesis.

    PubMed

    Worthington, Andrew S; Burkart, Michael D

    2007-03-20

    Non-ribosomal peptides are built from both proteinogenic and non-proteinogenic amino acids. The latter resemble amino acids but contain modifications not found in proteins. The recent characterization of a non-heme Fe(2+) and alpha-ketoglutarate-dependent oxygenase that stereospecifically generates beta-hydroxyasparagine, an unnatural amino acid building block for the biosynthesis of calcium-dependent antibiotic, a lipopeptide antibiotic. This work improves our understanding of how these non-proteinogenic amino acids are synthesized.

  5. Further improvement in ganoderic acid production in static liquid culture of Ganoderma lucidum by integrating nitrogen limitation and calcium ion addition.

    PubMed

    Li, Huan-Jun; Zhang, De-Huai; Han, Li-Liang; Yu, Xuya; Zhao, Peng; Li, Tao; Zhong, Jian-Jiang; Xu, Jun-Wei

    2016-01-01

    To further improve the ganoderic acid (GA) production, a novel integrated strategy by combining nitrogen limitation and calcium ion addition was developed. The effects of the integrated combination on the content of GA-T (one powerful anticancer compound), their intermediates (squalene and lanosterol) and on the transcription levels of GA biosynthetic genes in G. lucidum fermentation were investigated. The maximum GA-T content with the integrated strategy were 1.87 mg/ 100 mg dry cell weight, which was 2.1-4.2 fold higher than that obtained with either calcium ion addition or nitrogen limitation alone, and it is also the highest record as ever reported in submerged fermentation of G. lucidum. The squalene content was increased by 3.9- and 2.2-fold in this case compared with either individual strategy alone. Moreover, the transcription levels of the GA biosynthetic genes encoding 3-hydroxy-3-methyglutaryl coenzyme A reductase and lanosterol synthase were also up-regulated by 3.3-7.5 and 1.3-2.3 fold, respectively.

  6. Calcium nephrolithiasis: effect of water hardness on urinary electrolytes.

    PubMed

    Schwartz, Bradley F; Schenkman, Noah S; Bruce, Jeremy E; Leslie, Stephen W; Stoller, Marshall L

    2002-07-01

    To analyze the impact of water hardness from public water supplies on calcium stone incidence and 24-hour urine chemistries in patients with known calcium urinary stone formation. Patients are frequently concerned that their public water supply may contribute to urinary stone disease. Investigators have documented an inverse relationship between water hardness and calcium lithogenesis. Others have found no such association. Patients who form calcium stones (n = 4833) were identified geographically by their zip code. Water hardness information from distinct geographic public water supplies was obtained, and patient 24-hour urine chemistries were evaluated. Drinking water hardness was divided into decile rankings on the basis of the public water supply information obtained from the Environmental Protection Agency. These data were compared with patient questionnaires and 24-hour urine chemistries. The calcium and magnesium levels in the drinking water were analyzed as independent variables. The number of total lifetime stone episodes was similar between patients residing in areas with soft public water and hard public water. Patients consuming the softest water decile formed 3.4 lifetime stones and those who consumed the hardest water developed 3.0 lifetime stones (P = 0.0017). The 24-hour urine calcium, magnesium, and citrate levels increased directly with drinking water hardness, and no significant change was found in urinary oxalate, uric acid, pH, or volume. The impact of water hardness on urinary stone formation remains unclear, despite a weak correlation between water hardness and urinary calcium, magnesium, and citrate excretion. Tap water, however, can change urinary electrolytes in patients who form calcium stones.

  7. Gallbladder mucin production and calcium carbonate gallstones in children.

    PubMed

    Sayers, Craig; Wyatt, Judy; Soloway, Roger D; Taylor, Donald R; Stringer, Mark D

    2007-03-01

    In contrast to adults, calcium carbonate gallstones are relatively common in children. Their pathogenesis is poorly understood. Cystic duct obstruction promotes calcium carbonate formation in bile and increases gallbladder mucin production. We tested the hypothesis that mucin producing epithelial cells would be increased in gallbladders of children with calcium carbonate gallstones. Archival gallbladder specimens from 20 consecutive children who had undergone elective cholecystectomy for cholelithiasis were examined. In each case, gallstone composition was determined by Fourier transform infrared microspectroscopy. Gallbladder specimens from six children who had undergone cholecystectomy for conditions other than cholelithiasis during the same period were used as controls. Multiple sections were examined in a blinded fashion and scored semiquantitatively for mucin production using two stains (alcian blue and periodic acid-Schiff). Increased mucin staining was observed in 50% or more epithelial cells in five gallbladder specimens from seven children with calcium carbonate stones, compared to 5 of 13 with other stone types (P = 0.17) and none of the control gallbladders (P = 0.02). Gallbladders containing calcium carbonate stones were significantly more likely than those containing other stone types or controls to contain epithelial cells with the greatest mucin content (P = 0.03). Gallbladders containing calcium carbonate stones were also more likely to show the ulcer-associated cell lineage. These results demonstrate an increase in mucin producing epithelial cells in gallbladders from children containing calcium carbonate stones. This supports the hypothesis that cystic duct obstruction leading to increased gallbladder mucin production may play a role in the development of calcium carbonate gallstones in children.

  8. CALCIUM AND PHOSPHORUS METABOLISM IN OSTEOMALACIA

    PubMed Central

    Miles, Lee Monroe; Feng, Chih-Tung

    1925-01-01

    Osteomalacia is a diet deficiency disease of the same category as rickets. The deficiency is principally in the fat-soluble vitamine content of the diet, though there may be a calcium deficiency at the same time. The disease may be prevented by providing a diet rich in the fat-soluble vitamine content, and may be cured by adding the same to the diet. PMID:19868970

  9. Total prevention of folic acid-preventable spina bifida and anencephaly would reduce child mortality in India: Implications in achieving Target 3.2 of the Sustainable Development Goals.

    PubMed

    Kancherla, Vijaya; Oakley, Godfrey P

    2018-03-15

    The potential to reduce child mortality by preventing folic acid-preventable spina bifida and anencephaly (FAP SBA) is inadequately appreciated. To quantify possible reduction in FAP SBA-associated child mortality in low- and middle-income countries, we conducted an analysis to demonstrate in India, a country with more than 25 million births and 1.2 million under-five deaths each year, the decrease in neonatal, infant, and under-five mortality that would occur through total prevention of FAP SBA. We estimated the percent reductions in neonatal, infant, and under-five mortality that would have occurred in India in 2015 had all of FAP SBA been prevented. We also estimated the contributions of these reductions toward India's Sustainable Development Goals on child mortality indicators. We considered the overall prevalence of spina bifida and anencephaly in India as 5 per 1,000 live births, of which 90% were preventable with effective folic acid intervention. In the year 2015, folic acid interventions would have prevented about 116,070 cases of FAP SBA and 101,565 under-five deaths associated with FAP SBA. Prevention of FAP SBA would have reduced annually, neonatal, infant, and under-five mortality by 10.2%, 8.9%, and 8.3%, respectively. These reductions would have contributed 18.5% and 17.2% to the reductions in neonatal and under-five mortality, respectively, needed by India to achieve its 2030 Sustainable Developmental Goal Target 3.2 addressing preventable child mortality. Total prevention of FAP SBA clearly has a significant potential for immediate reductions in neonatal, infant, and under-five mortality in India, and similarly other countries. © 2017 Wiley Periodicals, Inc.

  10. Calcium deprivation increases the palatability of calcium solutions in rats.

    PubMed

    McCaughey, Stuart A; Forestell, Catherine A; Tordoff, Michael G

    2005-02-15

    Calcium-deprived rats have elevated intakes of CaCl2, other calcium salts, and some non-calcium compounds. We used taste reactivity to examine the effects of calcium deprivation on the palatability of CaCl2 and other solutions. Nine male Sprague-Dawley rats were calcium-deprived by maintenance on a low-calcium diet, and eight replete rats were used as controls. All rats were videotaped during intraoral infusion of the following solutions: 30 and 300 mM CaCl2, 30 mM calcium lactate, 100 and 600 mM NaCl, 30 mM MgCl2, 1 mM quinine.HCl, 2.5 mM sodium saccharin, and deionized water. We counted individual orofacial and somatic movements elicited by the infusions and used them to calculate total ingestive and aversive scores. Relative to controls, calcium-deprived rats gave a significantly larger number of tongue protrusions and had higher total ingestive scores for CaCl2, calcium lactate, NaCl, and MgCl2. Our results suggest that CaCl2, calcium lactate, NaCl, and MgCl2 taste more palatable to rats when they are calcium-deprived than replete, and this may be responsible for the increased intake of these solutions following calcium deprivation.

  11. Altered steady state pharmacokinetics of levofloxacin in adult cystic fibrosis patients receiving calcium carbonate.

    PubMed

    Pai, Manjunath P; Allen, Sarah E; Amsden, Guy W

    2006-08-01

    Levofloxacin is used in adult patients with cystic fibrosis but its pharmacokinetics is not well characterized in this population. Patients with cystic fibrosis use calcium routinely to prevent osteoporosis. A slower intestinal transit time is common in cystic fibrosis implying that the standard 2-h spacing of minerals and levofloxacin to prevent a chelation interaction may be insufficient. The objectives of this study were to characterize the steady state pharmacokinetics of oral levofloxacin 750 mg with and without 2-h spaced calcium carbonate in patients with cystic fibrosis compared to matched healthy volunteers. In an open-label, randomized, cross-over study of five patients with cystic fibrosis and five age, sex, race, and serum creatinine matched healthy volunteers received 750 mg of oral levofloxacin alone daily for 5 days and the same dose of levofloxacin with 2-h spaced calcium carbonate supplementation 500 mg po thrice daily with meals in random sequence. Blood was collected for plasma assay of levofloxacin pre-dose, 0.5, 1, 1.5, 2, 4, 8, 12, and 24h after the fifth levofloxacin dose. There was no significant interaction in healthy volunteers, however, when cystic fibrosis patients were given levofloxacin with 2-h spaced calcium, the maximum plasma concentration (Cmax) decreased by 19% and time to Cmax increased by 37% (p<0.05). This difference in peak concentrations resulted in a lack of bioequivalence (Cmax geometric mean ratio 81.6%, 90% confidence intervals: 71.8%, 91.4%) even when levofloxacin and calcium supplements were spaced by the standard 2h administration instruction in patients with cystic fibrosis. These results indicate that multivalent cations such as calcium should be maximally separated from oral levofloxacin administration in adult patients with cystic fibrosis to prevent this drug interaction, thereby better optimizing antibiotic efficacy and decreasing the potential for resistance development.

  12. The hyperthermophilic α-amylase from Thermococcus sp. HJ21 does not require exogenous calcium for thermostability because of high-binding affinity to calcium.

    PubMed

    Cheng, Huaixu; Luo, Zhidan; Lu, Mingsheng; Gao, Song; Wang, Shujun

    2017-05-01

    The hyperthermophilic α-amylase from Thermococcus sp. HJ21 does not require exogenous calcium ions for thermostability, and is a promising alternative to commercially available α-amylases to increase the efficiency of industrial processes like the liquefaction of starch. We analyzed the amino acid sequence of this α-amylase by sequence alignments and structural modeling, and found that this α-amylase closely resembles the α-amylase from Pyrococcus woesei. The gene of this α-amylase was cloned in Escherichia coli and the recombinant α-amylase was overexpressed and purified with a combined renaturation-purification procedure. We confirmed thermostability and exogenous calcium ion independency of the recombinant α-amylase and further investigated the mechanism of the independency using biochemical approaches. The results suggested that the α-amylase has a high calcium ion binding affinity that traps a calcium ion that would not dissociate at high temperatures, providing a direct explanation as to why the addition of calcium ions is not required for thermostability. Understanding of the mechanism offers a strong base on which to further engineer properties of this α-amylase for better potential applications in industrial processes.

  13. Effectiveness of acidic oxidative potential water in preventing bacterial infection in islet transplantation.

    PubMed

    Miyamoto, M; Inoue, K; Gu, Y; Hoki, M; Haji, S; Ohyanagi, H

    1999-01-01

    At a number of points in the current procedures of islet isolation and islet culture after the harvesting of donor pancreata, microorganisms could potentially infect the islet preparation. Furthermore, the use of islets from multiple donors can compound the risks of contamination of individual recipients. Acidic oxidative potential water (also termed electrolyzed strong acid solution, function water, or acqua oxidation water), which was developed in Japan, is a strong acid formed on the anode in the electrolysis of water containing a small amount of sodium chloride. It has these physical properties: pH, from 2.3 to 2.7; oxidative-reduction potential, from 1,000 to 1,100 mV; dissolved chlorine, from 30 to 40 ppm; and dissolved oxygen, from 10 to 30 ppm. Because of these properties, acidic oxidative potential water has strong bactericidal effects on all bacteria including methicillin-resistant Staphylococcus aureus (MRSA), viruses including HIV, HBV, HCV, CMV, and fungi as a result of the action of the active oxygen and active chlorine that it contains. We conducted this study to evaluate the effect of acidic oxidative potential water irrigation on bacterial contamination on the harvesting of porcine pancreata from slaughterhouses for islet xenotransplantation by counting the number of pancreatic surface bacteria using the Dip-slide method, and on the results of islet culture; and to evaluate the direct effect on isolated islets when it is used to prevent bacterial contamination by the static incubation test and by morphological examination. Direct irrigation of the pancreas by acidic oxidative potential water was found to be very effective in preventing bacterial contamination, but direct irrigation of isolated islets slightly decreased their viability and function.

  14. Tartaric Acid as a Non-toxic and Environmentally-Friendly Anti-scaling Material for Using in Cooling Water Systems: Electrochemical and Surface Studies

    NASA Astrophysics Data System (ADS)

    Asghari, Elnaz; Gholizadeh-Khajeh, Maryam; Ashassi-Sorkhabi, Habib

    2016-10-01

    Because of the major limitations in drinking water resources, the industries need to use unprocessed water sources for their cooling systems; these water resources contain major amount of hardening cations. So, mineral scales are formed in cooling water systems during the time and cause major problems. The use of green anti-scaling materials such as carboxylic acids is considered due to their low risks of environmental pollution. In the present work, the scale inhibition performance of tartaric acid as a green organic material was evaluated. Chemical screening tests, cathodic and anodic voltammetry measurements and electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), energy-dispersive x-ray and x-ray diffraction, were used for the evaluation of the scale inhibition performance. The results showed that tartaric acid can prevent calcium carbonate precipitation significantly. The hard water solution with 2.0 mM of tartaric acid indicated the highest scale inhibition efficiency (ca. 68%). The voltammetry, EIS and FESEM results verified that tartaric acid can form smooth and homogeneous film on steel surface through formation of Fe(III)-tartrate complexes and retard the local precipitation of calcium carbonate deposits.

  15. Calcium and lanthanum solid base catalysts for transesterification

    DOEpatents

    Ng, K. Y. Simon; Yan, Shuli; Salley, Steven O.

    2015-07-28

    In one aspect, a heterogeneous catalyst comprises calcium hydroxide and lanthanum hydroxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In another aspect, a heterogeneous catalyst comprises a calcium compound and a lanthanum compound, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g, and a total basicity of about 13.6 mmol/g. In further another aspect, a heterogeneous catalyst comprises calcium oxide and lanthanum oxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In still another aspect, a process for preparing a catalyst comprises introducing a base precipitant, a neutral precipitant, and an acid precipitant to a solution comprising a first metal ion and a second metal ion to form a precipitate. The process further comprises calcining the precipitate to provide the catalyst.

  16. Studies on the production of endogenous pyrogen by rabbit monocytes: the role of calcium and cyclic nucleotides.

    PubMed

    Sigal, S L; Duff, G W; Atkins, E

    1985-01-01

    Rabbit monocytes stimulated with endotoxin produced endogenous pyrogen, even under conditions of high or low extracellular calcium concentrations. Maximal production occurred when the concentration was in the near-physiological range. Prolonged incubation of cells with a calcium chelator prevented subsequent activation with endotoxin, an effect which was rapidly reversible by re-addition of calcium but not other cations. Addition of small amounts of lanthanum, which acts as a calcium channel blocker, prevented the restoration of pyrogen production, indicating that entry of the added calcium into the monocyte was required. Incorporation of a calcium ionophore into the cell membrane did not stimulate pyrogen production, and no measurable influx or efflux of calcium occurred during stimulation with endotoxin. These observations suggest that a slowly exchangeable calcium pool is necessary for the production of endogenous pyrogen, but that a rise in intracellular calcium is not by itself a necessary or sufficient stimulus. This stands in contrast to other biological systems in which Ca2+ directly couples stimulus and hormone secretion. Incubation of cells with agents shown to increase cyclic 3',5' AMP or cyclic 3',5' GMP levels in monocytes similarly did not stimulate pyrogen production or modulate its production by endotoxin stimulation. Thus, cyclic nucleotides also did not play a detectable role as intracellular messengers in this system. Future work is required to define more clearly the mechanism for the production of endogenous pyrogen, given its marked effects on the immune system through lymphocyte activation and temperature regulation.

  17. SNF1-related protein kinases 2 are negatively regulated by a plant-specific calcium sensor.

    PubMed

    Bucholc, Maria; Ciesielski, Arkadiusz; Goch, Grażyna; Anielska-Mazur, Anna; Kulik, Anna; Krzywińska, Ewa; Dobrowolska, Grażyna

    2011-02-04

    SNF1-related protein kinases 2 (SnRK2s) are plant-specific enzymes involved in environmental stress signaling and abscisic acid-regulated plant development. Here, we report that SnRK2s interact with and are regulated by a plant-specific calcium-binding protein. We screened a Nicotiana plumbaginifolia Matchmaker cDNA library for proteins interacting with Nicotiana tabacum osmotic stress-activated protein kinase (NtOSAK), a member of the SnRK2 family. A putative EF-hand calcium-binding protein was identified as a molecular partner of NtOSAK. To determine whether the identified protein interacts only with NtOSAK or with other SnRK2s as well, we studied the interaction of an Arabidopsis thaliana orthologue of the calcium-binding protein with selected Arabidopsis SnRK2s using a two-hybrid system. All kinases studied interacted with the protein. The interactions were confirmed by bimolecular fluorescence complementation assay, indicating that the binding occurs in planta, exclusively in the cytoplasm. Calcium binding properties of the protein were analyzed by fluorescence spectroscopy using Tb(3+) as a spectroscopic probe. The calcium binding constant, determined by the protein fluorescence titration, was 2.5 ± 0.9 × 10(5) M(-1). The CD spectrum indicated that the secondary structure of the protein changes significantly in the presence of calcium, suggesting its possible function as a calcium sensor in plant cells. In vitro studies revealed that the activity of SnRK2 kinases analyzed is inhibited in a calcium-dependent manner by the identified calcium sensor, which we named SCS (SnRK2-interacting calcium sensor). Our results suggest that SCS is involved in response to abscisic acid during seed germination most probably by negative regulation of SnRK2s activity.

  18. Expression of the high capacity calcium-binding domain of calreticulin increases bioavailable calcium stores in plants

    NASA Technical Reports Server (NTRS)

    Wyatt, Sarah E.; Tsou, Pei-Lan; Robertson, Dominique; Brown, C. S. (Principal Investigator)

    2002-01-01

    Modulation of cytosolic calcium levels in both plants and animals is achieved by a system of Ca2+-transport and storage pathways that include Ca2+ buffering proteins in the lumen of intracellular compartments. To date, most research has focused on the role of transporters in regulating cytosolic calcium. We used a reverse genetics approach to modulate calcium stores in the lumen of the endoplasmic reticulum. Our goals were two-fold: to use the low affinity, high capacity Ca2+ binding characteristics of the C-domain of calreticulin to selectively increase Ca2+ storage in the endoplasmic reticulum, and to determine if those alterations affected plant physiological responses to stress. The C-domain of calreticulin is a highly acidic region that binds 20-50 moles of Ca2+ per mole of protein and has been shown to be the major site of Ca2+ storage within the endoplasmic reticulum of plant cells. A 377-bp fragment encoding the C-domain and ER retention signal from the maize calreticulin gene was fused to a gene for the green fluorescent protein and expressed in Arabidopsis under the control of a heat shock promoter. Following induction on normal medium, the C-domain transformants showed delayed loss of chlorophyll after transfer to calcium depleted medium when compared to seedlings transformed with green fluorescent protein alone. Total calcium measurements showed a 9-35% increase for induced C-domain transformants compared to controls. The data suggest that ectopic expression of the calreticulin C-domain increases Ca2+ stores, and that this Ca2+ reserve can be used by the plant in times of stress.

  19. Calcium ionization balance and argon/calcium abundance in solar flares

    NASA Astrophysics Data System (ADS)

    Antonucci, E.; Marocchi, D.; Gabriel, A. H.; Doschek, G. A.

    1987-12-01

    An earlier analysis of solar flare calcium spectra from XRP and P78-1 aimed at measuring the calcium ionization balance resulted in an ambiguity due to a line blend between the calcium q line and an Ar XVII line. In the present work the calcium line 'r' is included in the analysis in order to resolve this problem. It is shown that the correct calcium ionization balance is that indicated in the earlier paper as corresponding to an argon/calcium abundance ratio of 0.2. The argon/calcium abundance ratio in the group of solar flares studied is shown to be 0.2 + or - 0.2. It is further argued that while the abundance of heavy elements may be enhanced in energetic flare events, this enhancement is less for argon than for calcium, leading to an argon/calcium ratio smaller than that present in the quiet sun.

  20. Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?

    PubMed Central

    2011-01-01

    The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis. PMID:21375761

  1. Two-pore channels: Regulation by NAADP and customized roles in triggering calcium signals

    PubMed Central

    Patel, Sandip; Marchant, Jonathan; Brailoiu, Eugen

    2010-01-01

    NAADP is a potent regulator of cytosolic calcium levels. Much evidence suggests that NAADP activates a novel channel located on an acidic (lysosomal-like) calcium store, the mobilisation of which results in further calcium release from the endoplasmic reticulum. Here, we discuss the recent identification of a family of poorly characterized ion channels (the two-pore channels) as endo-lysosomal NAADP receptors. The generation of calcium signals by these channels is likened to those evoked by depolarisation during excitation-contraction coupling in muscle. We discuss the idea that two pore-channels can mediate a trigger release of calcium which is then amplified by calcium-induced calcium release from the endoplasmic reticulum. This is similar to the activation of voltage-sensitive calcium channels and subsequent mobilisation of sarcoplasmic reticulum calcium stores in cardiac tissue. We suggest that two-pore channels may physically interact with ryanodine receptors to account for more direct release of calcium from the endoplasmic reticulum in analogy with the conformational coupling of voltage-sensitive calcium channels and ryanodine receptors in skeletal muscle. Interaction of two-pore channels with other calcium release channels likely occurs between stores “trans-chatter” and possibly within the same store “cis-chatter”. We also speculate that trafficking of two-pore channels through the endolysosomal system facilitates interactions with calcium entry channels. Strategic placing of two-pore channels thus provides a versatile means of generating spatiotemporally complex cellular calcium signals. PMID:20621760

  2. Regulation of transmural transport of amino acid/metal conjugates by dietary calcium in crustacean digestive tract.

    PubMed

    Abdel-Malak, Rania; Ahearn, Gregory A

    2014-03-01

    Effects of luminal Ca(2+) and Mn(2+) on transmural mucosal to serosal (MS) transport of (3) H-L-leucine were characterized in the isolated and perfused intestine of the American lobster, Homarus americanus. (3) H-L-leucine MS transport in the presence of 20 µM Mn(2+) was a sigmoidal function of luminal amino acid concentration, following the Hill equation for multisite cooperative, carrier-mediated, transport. Luminal Ca(2+) was a non-competitive inhibitor of Mn(2+) -stimulated (3) H-L-leucine MS flux. Amino acid transport was hyperbolically stimulated by luminal Ca(2+) or Mn(2+). During 20 µM Mn(2+) -stimulation of (3) H-L-leucine MS flux, addition of 25 mM Ca(2+) strongly reduced amino acid transport Jmax , without affecting amino acid binding properties. Hyperbolic luminal Mn(2+) stimulation of 20 µM (3) H-L-leucine MS flux was also strongly inhibited by 25 mM luminal Ca(2+) , significantly reducing 20 µM (3) H-L-leucine Jmax . Increasing the luminal concentration of verapamil, a calcium channel blocker, significantly increased MS transport of 20 µM (3) H-L-leucine in the presence of 100 nM Mn(2+) by reducing diffusional Ca(2+) uptake into intestinal epithelial cells through verapamil-sensitive channels. A model is proposed supporting the concept of molecular mimicry, whereby (3) H-L-leucine enters lobster intestinal epithelial cells by one or more amino acid-specific transporters and by a dipeptide-like transporter that is capable of binding and transporting peptide molecular mimics (bis-complexes) between Ca(2+) or Mn(2+) and (3) H-L-leucine using the membrane potential as a major driving force for the transport event. According to the model, Ca(2+) entry through apical Ca(2+) channels regulates the magnitude of the membrane potential and therefore the size of the driving force for bis-complex uptake. © 2013 Wiley Periodicals, Inc.

  3. Calcium Carbonate

    MedlinePlus

    ... Maalox® (as a combination product containing Calcium Carbonate, Simethicone) ... Relief (as a combination product containing Calcium Carbonate, Simethicone) ... Plus (as a combination product containing Calcium Carbonate, Simethicone)

  4. Ferulic Acid Suppresses Glutamate Release Through Inhibition of Voltage-Dependent Calcium Entry in Rat Cerebrocortical Nerve Terminals

    PubMed Central

    Lin, Tzu Yu; Lu, Cheng Wei; Huang, Shu-Kuei

    2013-01-01

    Abstract This study investigated the effects and possible mechanism of ferulic acid, a naturally occurring phenolic compound, on endogenous glutamate release in the nerve terminals of the cerebral cortex in rats. Results show that ferulic acid inhibited the release of glutamate evoked by the K+ channel blocker 4-aminopyridine (4-AP). The effect of ferulic acid on the evoked glutamate release was prevented by chelating the extracellular Ca2+ ions, but was insensitive to the glutamate transporter inhibitor DL-threo-beta-benzyl-oxyaspartate. Ferulic acid suppressed the depolarization-induced increase in a cytosolic-free Ca2+ concentration, but did not alter 4-AP–mediated depolarization. Furthermore, the effect of ferulic acid on evoked glutamate release was abolished by blocking the Cav2.2 (N-type) and Cav2.1 (P/Q-type) channels, but not by blocking ryanodine receptors or mitochondrial Na+/Ca2+ exchange. These results show that ferulic acid inhibits glutamate release from cortical synaptosomes in rats through the suppression of presynaptic voltage-dependent Ca2+ entry. PMID:23342970

  5. Risk of calcium oxalate nephrolithiasis in postmenopausal women supplemented with calcium or combined calcium and estrogen.

    PubMed

    Domrongkitchaiporn, Somnuek; Ongphiphadhanakul, Boonsong; Stitchantrakul, Wasana; Chansirikarn, Sirinthorn; Puavilai, Gobchai; Rajatanavin, Rajata

    2002-02-26

    Recent studies showed that postmenopausal women lost less bone mass when supplemented with calcium or estrogen therapy. However, the safety of the treatments in terms of the risk of calcium oxalate stone formation is unknown. We therefore conducted this study to determine the alteration in calcium oxalate supersaturation after calcium supplement or after combined calcium and estrogen therapy in postmenopausal osteoporotic women. Fifty-six postmenopausal women were enrolled in this study. All subjects were more than 10 years postmenopausal with vertebral or femoral osteoporosis by bone mineral density criteria. They were randomly allocated to receive either 625 mg of calcium carbonate (250 mg of elemental calcium) at the end of a meal three times a day (group A, n=26) or calcium carbonate in the same manner plus 0.625 mg/day of conjugated equine estrogen and 5 mg medrogestone acetate from day 1-12 each month (group B, n=30). The age (mean +/- S.E.M.) was 66.3 +/- 1.2 and 65.1 +/- 1.1 years, weight 54.1 +/- 1.2 and 55.3 +/- 2.1 kg, in group A and group B, respectively. Urine specimens (24-h) were collected at baseline and 3 months after treatment for the determination of calcium oxalate saturation by using Tiselius's index (AP(CaOx)) and calcium/citrate ratio. After 3 months of treatment, there was no significant alteration from baseline for urinary excretion of calcium, citrate and oxalate. Urinary phosphate excretion was significantly reduced (6.3 +/- 0.7 vs. 5.1 +/- 0.7 mmol/day for group A and 8.2 +/- 0.9 vs. 5.8 +/- 0.7 mmol/day for group B, P<0.05), whereas net alkaline absorption was significantly elevated (10.1 +/- 3.6 vs. 20.1 +/- 4.4 meq/day for group A and 4.8 +/- 3.2 vs. 19.9 +/- 3.6 meq/day for group B, P<0.05). Calcium/citrate ratio and AP(CaOx) determined at baseline were not different from the corresponding values after treatment in both groups; calcium/citrate: 10.1 +/- 3.1 vs. 10.1 +/- 2.5 for group A and 9.3 +/- 1.8 vs. 11.9 +/- 2.5 for group B and

  6. [Colorectal cancer preventive effect of combined administration of phenolic acids and supercritical extracts from Angelica sinensis].

    PubMed

    Peng, Yu; Zhao, Bo-Chen; Kang, Qian; Liu, Jia; Chen, Cheng; Li, Bing-Shao; Xie, Yuan-Ping; Wu, Qing

    2018-03-01

    This study aimed to investigate the colorectal cancer preventive effect of the combined administration of phenolic acids and supercritical extracts from Angelica sinensis. The AOM/DSS model in mice was adopted. Phenolic acids were administrated orally in the initial stage of the model at a dose of 1 g·kg⁻¹ BW, which was combined withtherectal administration with three doses of supercritical extracts (15, 30, 60 g·kg⁻¹ BW). PCNA, 8-oxoguaine, γ-H2AX, iNOS and COX-2 were tested by immunohistochemistry and Western blot assays. The results showed that the combined administration of phenolic acids and supercritical extracts from A. sinensis suppressed the tumor growth and cell proliferation, and DNA damages and inflammatory responses were reduced in a dose-dependent manner. These results indicate that the combined administration of phenolic acids and supercritical extracts from A. sinensis have a certain effect in preventing carcinogenesis. Copyright© by the Chinese Pharmaceutical Association.

  7. Meat and cancer: haemoglobin and haemin in a low-calcium diet promote colorectal carcinogenesis at the aberrant crypt stage in rats

    PubMed Central

    Pierre, Fabrice; Taché, Sylviane; Petit, Claude R; Van Der Meer, Roelof; Corpet, Denis E

    2003-01-01

    High intake of red meat, but not of white meat, is associated with an increased risk of colon cancer. However, red meat does not promote cancer in rodents. Haemin, added to low-calcium diets, increases colonic proliferation, and haemoglobin, added to high-fat diets, increases the colon tumour incidence in rats, an effect possibly due to peroxyl radicals. We thus speculated that haem might be the promoting agent in meat, and that prevention strategies could use calcium and antioxidants. These hypotheses were tested in rats at the aberrant crypt foci (ACF) stage at 100 days. F344 rats (n=124) were given an injection of azoxymethane and were then randomised to 11 groups fed with low-calcium (20μmol/g) AIN76-based diets, containing 5% safflower oil. Haemin (0.25, 0.5 and 1.5μmol/g) or haemoglobin (1.5 and 3 μmol haem/g) was added to five experimental diets, compared to a control diet without haem. Three other high-haemin diets (1.5μmol/g) were supplemented with calcium (250μmol/g), antioxidant butylated hydroxyanisole and rutin (0.05% each), and olive oil, which replaced safflower oil. Faecal water was assayed for lipid peroxidation by thiobarbituric acid reactive substances (TBARs) test, and for cytolytic activity. Haemin strikingly increased the ACF size, dose-dependently, from 2.6 to 11.4 crypts/ACF (all p<0.001). The high-haemin diet also increased the number of ACF per colon (p<0.001). Promotion was associated with increased faecal water TBARs and cytotoxicity. Calcium, olive oil, and antioxidants each inhibited the haemin-induced ACF promotion, and normalised the faecal TBARs and cytotoxicity. The haemoglobin diets increased the number of ACF and faecal TBARs, but not the ACF size or the faecal cytotoxicity. In conclusion, dietary haemin is the most potent known ACF promoter. Haemoglobin is also a potent promoter of colorectal carcinogenesis. The results suggest that myoglobin in red meat could promote colon cancer. Diets high in calcium, or in oxidation

  8. Synthesization and characterization of poly(lactic-co-glycolic acid) / calcium phosphate bone cement from crab shells

    NASA Astrophysics Data System (ADS)

    Hanan, M. R. Abdul; Daud, N. M.; Ismail, L. H.; Saidin, S.

    2017-05-01

    An injectable calcium phosphate (CaP) bone cement has been widely used for musculoskeletal and bone disorder due to its biocompatible and osteoconductive properties. In this study, CaP was successfully synthesized from crab shells by a wet chemical route. Poly(lactic-co-glycolic acid) (PLGA) microspheres which have been produced through a double emulsion technique were incorporated into the CaP mixture for the purpose of bone cement solidification. The ratio of both compounds, CaP and PLGA, were set at 8:2. The CaP and PLGA/CaP bone cement were analyzed by ATR-FTIR, FESEM-EDX and contact angle analyses. The bone cement was composed of CaP and PLGA where the micro-powders of CaP were agglomerated on the PLGA microspheres. Addition of the PLGA has increased the hydrophilicity of the bone cement which will be beneficial for materials degradation and bone integration.

  9. Expanding the range of free calcium regulation in biological solutions.

    PubMed

    Dweck, David; Reyes-Alfonso, Avelino; Potter, James D

    2005-12-15

    Many biological systems use ethylene glycol bis (beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) to regulate the free calcium concentration ([Ca(2+)](free)) in the presence of physiological levels of free Mg(2+) ([Mg(2+)](free)). Frequently, it is necessary to work at [Ca(2+)](free) beyond EGTA's buffering capabilities. Therefore, we have developed methods to extend the buffering range by adding nitrilotriacetic acid (NTA) to solutions containing EGTA. This extension results from NTA having a lower K'(dCa) than EGTA. Such equilibria are solved by pCa Calculator, a computer program designed to aid in the study of Ca(2+)-dependent physiological processes while accounting for the effects of pH, temperature, and ionic strength. With multiple chelators and pH buffers from which to choose, pCa Calculator calculates the total concentration of each species required to achieve specified free concentrations of Ca(2+), ATP, and Mg(2+). The program is intuitive, user-friendly, and flexible enough to fix or vary the [Mg-ATP(2-)] and ionic strength. Moreover, it can account for increases in experimental volume from calcium addition. A comparative analysis is reported for testing solutions in the presence and absence of NTA by measuring the calcium binding affinity of fluorescent cardiac troponin C. These findings demonstrate that EGTA, when used in conjunction with NTA, improves and expands the regulation of free calcium in solution.

  10. Effects Sprayed Solution of Salicylic Acid to Prevent of Wilt Disease Caused by Fussarium oxysporium

    NASA Astrophysics Data System (ADS)

    Yousif, Dina. Y. M.

    2018-05-01

    The current search aimed to detective the effect of sprayed solution of salicylic acid on plant and leaves of sweet green pepper (Capsicum annuum) for control the pathogen Fussarium oxysporium compering with control plant and leaves. Results indicated that, the spray of salicylic acid at concentration 0.5 g/L is effecting the fungal infection through prevent transport fungus F. oxysporum to the neighboring green pepper plant. The number of dead green pepper plant after sprayed with solution of salicylic acid and only water they were (4, 6, and 3) (8, 9, and 10) respectively. While the experimental infection of green pepper leaves after inoculated the fungus as local spot by scorching small spots of these leaves with the aid of hot nail. These spots were then exposed to the 0.5 g/L aqueous solution salicylic acid before and after the inoculation of the fungus. The spray of salicylic acid before 24 and 48 hour prevent the development of disease and make a good protection of the mention leaves from infection with this fungus, the diameter of leaves lesion (1,1.5 cm) respectively. while the ability of fungus to grow after 24 and 48 hour from salicylic acid treatment was markedly reduce as compared with control, such treatment show slow growth of pathogen infect.

  11. Enhanced removal of humic acid from aqueous solution by novel stabilized nano-amorphous calcium phosphate: Behaviors and mechanisms

    NASA Astrophysics Data System (ADS)

    Jiang, Ling; Li, Yiming; Shao, Yi; Zhang, Yong; Han, Ruiming; Li, Shiyin; Wei, Wei

    2018-01-01

    Stabilized nano-amorphous calcium phosphate (nACP) was prepared using polyethylene glycol as stabilizer to obtain a nanosized amorphous adsorbent. The produced nACP was evaluated by using XRD, FTIR, SEM and X-ray photoelectron spectroscopy (XPS). The sedimentation test demonstrated that nACP exhibited better stability than crystallized hydroxyapatite. The adsorption efficiency of the nACP material for aqueous humic acid (HA) was evaluated from the point of view of medium pH, adsorption time, temperature, and ionic strength, as well as the presences of metal ions. The results of the study showed very good adsorption performance towards aqueous HA. The Sips modeling results revealed that the stabilized nACP adsorbent had a considerably high adsorption capacity (248.3 mg/g) for HA at 298 K. The adsorption data fitted well into pseudo-second order and Elovich kinetic models. XPS analyses indicated that HA retention on nACP material might be due to the surface complexation reaction between oxygen-containing group and calcium of HA and nACP, respectively. Moreover, the HA adsorption capacity of nACP could still keep more than 86% after four adsorption-desorption cycles. By taking into account all results it was concluded that the nACP adsorbent leveraged its stability in combination with its high uptake capacity to offer a great promise for HA adsorption from water.

  12. Calcium Ions as “Miscibility Switch”: Colocalization of Surfactant Protein B with Anionic Lipids under Absolute Calcium Free Conditions

    PubMed Central

    Saleem, Mohammed; Meyer, Michaela C.; Breitenstein, Daniel; Galla, Hans-Joachim

    2009-01-01

    Abstract One of the main determinants of lung surfactant function is the complex interplay between its protein and lipid components. The lipid specificity of surfactant protein B (SP-B), however, and the protein's ability to selectively squeeze out lipids, has remained contradictory. In this work we present, for the first time to our knowledge, by means of time-of-flight secondary ion mass spectrometry chemical imaging, a direct evidence for colocalization of SP-B as well as its model peptide KL4 with negatively charged dipalmitoylphosphatidylglycerol under absolute calcium free conditions. Our results prove that protein/lipid localization depends on the miscibility of all surfactant components, which itself is influenced by subphase ionic conditions. In contrast to our earlier studies reporting SP-B/KL4 colocalization with zwitterionic dipalmitoylphosphatidylcholine, in the presence of even the smallest traces of calcium, we finally evidence an apparent reversal of protein/lipid mixing behavior upon calcium removal with ethylene diamine tetraacetic acid. In addition, scanning force microscopy measurements reveal that by depleting the subphase from calcium ions the protrusion formation ability of SP-B or KL4 is not hampered. However, in the case of KL4, distinct differences in protrusion morphology and height are visible. Our results support the idea that calcium ions act as a “miscibility switch” in surfactant model systems and probably are one of the major factors steering lipid/protein mixing behavior as well as influencing the protein's protrusion formation ability. PMID:19619464

  13. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  14. The role of calcium in the nuclear maturation of Bufo arenarum oocytes.

    PubMed

    Zelarayán, Liliana I; Toranzo, Graciela Sánchez; Oterino, Julia M; Bühler, Marta I

    2004-02-01

    In Bufo arenarum, progesterone is the physiological maturation inducer. However, in this species, oocytes reinitiate meiosis with no need of an exogenous hormonal stimulus when deprived of their enveloping cell, a phenomenon called spontaneous maturation. We demonstrated that in Bufo arenarum spontaneous maturation occurs only in oocytes obtained during the reproductive period, which can be considered competent to mature spontaneously, in contrast to those in the non-reproductive period, which are incompetent. Interestingly, full-grown Bufo arenarum oocytes always respond to progesterone regardless of the season in which they are obtained. There is a general consensus that both a transient increase in intracellular calcium and a decrease in cAMP-dependent protein kinase activity are the first steps in the mechanisms by which progesterone induces maturation in amphibians. In the present work we analysed the role of calcium in the spontaneous and progesterone-induced maturation of Bufo arenarum oocytes. Results demonstrated that the absence of calcium in the incubation medium or the prevention of Ca(2+) influx by channel blockers such as CdCl2 or NiCl2 did not prevent meiosis reinitiation in either type of maturation. The inhibition of the Ca(2+)-calmodulin complex in no case affected the maturation of the treated oocytes. However, when the oocytes were deprived of calcium by incubation in Ca(2+)-free AR + A23187, meiosis resumption was inhibited. In brief, we demonstrated that in Bufo arenarum the reinitiation of meiosis is a process independent of extracellular calcium at any period of the year and that oocytes require adequate levels of intracellular calcium for germinal vesicle breakdown to occur.

  15. Characterization of postsynaptic calcium signals in the pyramidal neurons of anterior cingulate cortex

    PubMed Central

    Li, Xu-Hui; Song, Qian; Chen, Tao; Zhuo, Min

    2017-01-01

    Calcium signaling is critical for synaptic transmission and plasticity. N-methyl-D-aspartic acid (NMDA) receptors play a key role in synaptic potentiation in the anterior cingulate cortex. Most previous studies of calcium signaling focus on hippocampal neurons, little is known about the activity-induced calcium signals in the anterior cingulate cortex. In the present study, we show that NMDA receptor-mediated postsynaptic calcium signals induced by different synaptic stimulation in anterior cingulate cortex pyramidal neurons. Single and multi-action potentials evoked significant suprathreshold Ca2+ increases in somas and spines. Both NMDA receptors and voltage-gated calcium channels contributed to this increase. Postsynaptic Ca2+signals were induced by puff-application of glutamate, and a NMDA receptor antagonist AP5 blocked these signals in both somas and spines. Finally, long-term potentiation inducing protocols triggered postsynaptic Ca2+ influx, and these influx were NMDA receptor dependent. Our results provide the first study of calcium signals in the anterior cingulate cortex and demonstrate that NMDA receptors play important roles in postsynaptic calcium signals in anterior cingulate cortex pyramidal neurons. PMID:28726541

  16. Calcium-phosphate metabolism in patients with multiple sclerosis.

    PubMed

    Kubicka-Baczyk, K; Labuz-Roszak, B; Pierzchala, K; Adamczyk-Sowa, M; Machowska-Majchrzak, A

    2015-06-01

    The purpose of this study was to evaluate the concentration of 25-hydroxycholecalciferol and parameters of calcium-phosphate metabolism at different periods of relapsing-remitting multiple sclerosis (RRMS). Forty-five patients, residents of Poland (49°-50°, N), were enrolled in the study, i.e. 15 immediately after the diagnosis of RRMS, 15 at the early stage and 15 at the advanced stage of RRMS. The results were compared to values obtained in 20 age- and sex-matched controls. Lower serum concentrations of 25-hydroxycholecalciferol and ionised calcium were found in patients compared to the control group. In patients with the disease duration of 5-6 years, concentrations of 25-hydroxycholecalciferol and ionised calcium were lower than in patients in the earlier period of RRMS. The inverse and clearer direction of changes was found in parathormone serum concentration in patients compared to the controls. In patients with a longer disease duration, a significantly lower 25-hydroxycholecalciferol concentration was found in female patients compared to male patients. In patients, more frequent 25-hydroxycholecalciferol and unsaturated fatty acids' supplementation was observed compared to the controls. In RRMS patients, calcium-phosphate metabolism is disturbed which increases during disease progression.

  17. Calcium carbonate precipitation by heterotrophic bacteria isolated from biofilms formed on deteriorated ignimbrite stones: influence of calcium on EPS production and biofilm formation by these isolates.

    PubMed

    López-Moreno, Angélica; Sepúlveda-Sánchez, José David; Mercedes Alonso Guzmán, Elia Mercedes; Le Borgne, Sylvie

    2014-01-01

    Heterotrophic CaCO3-precipitating bacteria were isolated from biofilms on deteriorated ignimbrites, siliceous acidic rocks, from Morelia Cathedral (Mexico) and identified as Enterobacter cancerogenus (22e), Bacillus sp. (32a) and Bacillus subtilis (52g). In solid medium, 22e and 32a precipitated calcite and vaterite while 52g produced calcite. Urease activity was detected in these isolates and CaCO3 precipitation increased in the presence of urea in the liquid medium. In the presence of calcium, EPS production decreased in 22e and 32a and increased in 52g. Under laboratory conditions, ignimbrite colonization by these isolates only occurred in the presence of calcium and no CaCO3 was precipitated. Calcium may therefore be important for biofilm formation on stones. The importance of the type of stone, here a siliceous stone, on biological colonization is emphasized. This calcium effect has not been reported on calcareous materials. The importance of the effect of calcium on EPS production and biofilm formation is discussed in relation to other applications of CaCO3 precipitation by bacteria.

  18. Lactose maldigestion, calcium intake and osteoporosis in African-, Asian-, and Hispanic-Americans.

    PubMed

    Jackson, K A; Savaiano, D A

    2001-04-01

    Dietary calcium is critical for the development of the human skeleton and likely plays an important role in the prevention of osteoporosis. Dairy products provide approximately three-fourths of calcium consumed in the diet and are the most concentrated sources of this essential nutrient. One obstacle that likely interferes with calcium consumption among many ethnic groups is lactose maldigestion. The real or perceived occurrence of intolerance symptoms after dairy food consumption may cause maldigesters to avoid dairy products. Several investigators have observed a relationship between lactose maldigestion, dietary calcium and osteoporosis in Caucasian populations. Research on ethnically diverse populations is necessary to better understand how lactose maldigestion influences the risk for osteoporosis. Low calcium intakes, a greater than previously thought potential for low bone density and extensive lactose maldigestion among Hispanic-American and Asian-American populations may create an elevated risk for osteoporosis. Dietary management strategies for lactose maldigesters to increase calcium consumption include consuming (1) dairy foods with meals, (2) yogurts, (3) calcium-fortified foods, (4) using lactose digestive aids and (5) including dairy foods daily in the diet to enhance colonic metabolism of lactose.

  19. Importance of the regiospecific distribution of long-chain saturated fatty acids on gut comfort, fat and calcium absorption in infants.

    PubMed

    Petit, Valérie; Sandoz, Laurence; Garcia-Rodenas, Clara L

    2017-06-01

    Gastrointestinal tolerance and fat and calcium (Ca) absorption are different between breast-fed (BF) and formula-fed (FF) infants. Certain components and/or structural particularities in human milk (HM), can contribute to favorable outcomes in BF infants. In HM, the long-chain saturated fatty acid (LCSFA) palmitic acid has a different stereospecific distribution (sn-2 position) compared to most infant formula (IF) (primarily sn-1, 3 positions), which may contribute to unfavorable outcomes. Evidence suggests palmitic acid is important in the formation of stool FA-mineral (or FA-Ca) soaps, associated with harder stools in FF infants. Partial replacement by structured palmitic acid-rich triacylglycerols (TAGs) promotes palmitic acid absorption. However, evidence for stool softening, improved fat absorption and reduced Ca excretion in stools is inconsistent. IFs with less palmitic acid can improve fat and Ca absorption, and stool consistency. The presence of other LCSFAs (myristic and stearic acids) in sn-1, 3 positions may also contribute to reduced absorption of fat and Ca, and stool hardness, in FF infants. Nevertheless, little attention has been given to modifying these other LCSFAs in IF. We review literature comparing the effect of HM and IF with different lipid compositions on stool patterns and/or fat and Ca absorption in healthy, term infants. Based on available data, we estimate a maximum level for sn-1, 3 LCSFAs of 13% of TAGs, under which fat and Ca absorption and stool consistency are improved. IF designed according to this threshold could efficiently improve nutrient absorption and stool patterns in healthy infants who cannot be breast-fed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Cinnamic Acid and Its Derivatives: Mechanisms for Prevention and Management of Diabetes and Its Complications

    PubMed Central

    Adisakwattana, Sirichai

    2017-01-01

    With recent insight into the development of dietary supplements and functional foods, search of effective phytochemical compounds and their mechanisms involved in prevention and management of diabetes and its complications are now being assessed. Cinnamic acid and its derivatives occur naturally in high levels of plant-based foods. Among various biological activities, cinnamic acid and its derivatives are associated with a beneficial influence on diabetes and its complications. The aim of the review is to summarize the potential mechanisms of these compounds for prevention and management of diabetes and its complications. Based on several in vitro studies and animal models, cinnamic acid and its derivatives act on different mechanism of actions, including stimulation of insulin secretion, improvement of pancreatic β-cell functionality, inhibition of hepatic gluconeogenesis, enhanced glucose uptake, increased insulin signaling pathway, delay of carbohydrate digestion and glucose absorption, and inhibition of protein glycation and insulin fibrillation. However, due to the limited intestinal absorption being a result of low bioavailability of cinnamic acid and its derivatives, current improvement efforts with entrapping into solid and liquid particles are highlighted. Further human clinical studies are needed to clarify the effects of cinnamic acid and its derivatives in diabetic patients. PMID:28230764