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Sample records for calcium 40

  1. 40 CFR 424.40 - Applicability; description of the covered calcium carbide furnaces with wet air pollution control...

    Science.gov (United States)

    2010-07-01

    ... covered calcium carbide furnaces with wet air pollution control devices subcategory. 424.40 Section 424.40... FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Covered Calcium Carbide Furnaces With Wet Air Pollution Control Devices Subcategory § 424.40 Applicability; description of the covered calcium carbide...

  2. 40 CFR 721.10012 - Manganate (MnO21-), calcium (2:1).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Manganate (MnO21-), calcium (2:1). 721... Substances § 721.10012 Manganate (MnO21-), calcium (2:1). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as manganate (MnO2 1 -), calcium (2:1) (PMN...

  3. Lenticular energy metabolism during exogenous calcium deprivation and during recovery: effects of dextran-40.

    Science.gov (United States)

    Glonek, T; Kopp, S J; Greiner, J V; Sanders, D R

    1985-02-01

    Phosphatic metabolites of the intact rabbit lens were quantitated as a function of time by phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy during in vitro incubations at 37 degrees C in calcium-sufficient and calcium-deficient modified Earle's buffer with and without the osmotic agent, Dextran-40. Intralenticular pH was determined from the resonance shift position of inorganic orthophosphate (Pi). Incubation of lenses in calcium-deficient buffer resulted in a pronounced, time-dependent decrease in lenticular adenosine triphosphate (ATP) levels. The half-life of ATP within the lens was 11 hr under these experimental conditions. A concomitant, essentially stoichiometric increase in adenosine diphosphate and Pi levels was observed also. The other phosphatic metabolites were unaffected by exogenous calcium deprivation except for adenosine and inosine monophosphate which accumulated with time. Dextran-40 (6%), which has been shown to prevent lens swelling under these same experimental conditions, did not influence the metabolic responses of the lens to external calcium deprivation and did not facilitate subsequent restoration of lens phosphatic metabolites following restoration of a physiologic calcium concentration to the supporting medium. The Dextran-40 did, however, promote the retention of intralenticular pH environment during the experimental period. These findings suggest that the previously reported Dextran-40-dependent recovery of intralenticular sodium and potassium concentrations to control levels following 10 hr of incubation in calcium-deficient media cannot be attributed to a direct energy-sparing action of Dextran-40 on lenticular energy metabolism. Instead, the mechanistic basis for the action of Dextran-40 would appear to be related to its colloid osmotic properties and its ability to prevent lenticular swelling, which otherwise occurs in the absence of Dextran under these experimental conditions. PMID:2579839

  4. 40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to...

  5. 40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium carbide production subcategory. The provisions of this subpart are applicable to discharges resulting...

  6. 40 CFR 424.50 - Applicability; description of the other calcium carbide furnaces subcategory.

    Science.gov (United States)

    2010-07-01

    ... calcium carbide furnaces subcategory. 424.50 Section 424.50 Protection of Environment ENVIRONMENTAL... CATEGORY Other Calcium Carbide Furnaces Subcategory § 424.50 Applicability; description of the other calcium carbide furnaces subcategory. The provisions of this subpart are applicable to...

  7. Low Density Lipoproteins Promote Unstable Calcium Handling Accompanied by Reduced SERCA2 and Connexin-40 Expression in Cardiomyocytes

    Science.gov (United States)

    Cabello, Nuria; Llach, Anna; Vallmitjana, Alexander; Benítez, Raúl; Badimon, Lina; Cinca, Juan; Llorente-Cortés, Vicenta; Hove-Madsen, Leif

    2013-01-01

    The damaging effects of high plasma levels of cholesterol in the cardiovascular system are widely known, but little attention has been paid to direct effects on cardiomyocyte function. We therefore aimed at testing the hypothesis that Low Density Lipoprotein (LDL) cholesterol affects calcium dynamics and signal propagation in cultured atrial myocytes. For this purpose, mRNA and protein expression levels were determined by real time PCR and western blot analysis, respectively, and intracellular calcium was visualized in fluo-4 loaded atrial HL-1 myocyte cultures subjected to field stimulation. At low stimulation frequencies all cultures had uniform calcium transients at all tested LDL concentrations. However, 500 µg LDL/mL maximally reduced the calcium transient amplitude by 43% from 0.30±0.04 to 0.17±0.02 (p<0.05). Moreover, LDL-cholesterol dose-dependently increased the fraction of alternating and irregular beat-to-beat responses observed when the stimulation interval was shortened. This effect was linked to a concurrent reduction in SERCA2, RyR2, IP3RI and IP3RII mRNA levels. SERCA2 protein levels were also reduced by 43% at 200 µg LDL/mL (p<0.05) and SR calcium loading was reduced by 38±6% (p<0.001). By contrast, HDL-cholesterol had no significant effect on SERCA expression or SR calcium loading. LDL-cholesterol also slowed the conduction velocity of the calcium signal from 3.2+0.2 mm/s without LDL to 1.7±0.1 mm/s with 500 µg LDL/mL (p<0.05). This coincided with a reduction in Cx40 expression (by 44±3%; p<0.05 for mRNA and by 79±2%; p<0.05 for Cx40 protein at 200 µg/ml LDL) whereas the Cx-43 expression did not significantly change. In conclusion, LDL-cholesterol destabilizes calcium handling in cultured atrial myocytes subjected to rapid pacing by reducing SERCA2 and Cx40 expression and by slowing the conduction velocity of the calcium signal. PMID:23516438

  8. 40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No....

  9. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  10. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  11. CALCIUM SIGNALING, ION CHANNELS AND MORE: THE DT40 SYSTEM AS A MODEL OF VERTEBRATE ION HOMEOSTASIS AND CELL PHYSIOLOGY

    OpenAIRE

    Perraud, Anne-Laure; Schmitz, Carsten; Scharenberg, Andrew M.

    2006-01-01

    The DT40 B-lymphocyte cell line is a chicken bursal lymphocyte tumor cell line which grows rapidly, expresses a variety of types of constitutive and signal dependent ion transport systems., and supports the efficient use of stable and conditional genetic manipulations. Below, we review the use of DT40 cells in dissecting molecular mechanisms involved in Ca2+, Mg2+, and Zn2+ transport physiology. These studies highlight the flexibility and advantages the DT40 environment offers to investigator...

  12. A Comparative Effectiveness Study of Bone Density Changes in Women Over 40 Following Three Bone Health Plans Containing Variations of the Same Novel Plant-sourced Calcium

    Directory of Open Access Journals (Sweden)

    Gilbert R. Kaats, Harry G. Preuss, Harry A. Croft, Samuel C. Keith, Patti L. Keith

    2011-01-01

    Full Text Available Background: The US Surgeon General's Report on Bone Health suggests America's bone-health is in jeopardy and issued a “call to action” to develop bone-health plans incorporating components of (1 improved nutrition, (2 increased health literacy, and (3 increased physical activity.Objective: To conduct a Comparative Effectiveness Research (CER study comparing changes in bone mineral density in healthy women over-40 with above-average compliance when following one of three bone health Plans incorporating the SG's three components.Methods: Using an open-label sequential design, 414 females over 40 years of age were tested, 176 of whom agreed to participate and follow one of three different bone-health programs. One Plan contained a bone-health supplement with 1,000 IUs of vitamin D3 and 750 mg of a plant-sourced form of calcium for one year. The other two Plans contained the same plant form of calcium, but with differing amounts of vitamin D3 and other added bone health ingredients along with components designed to increase physical activity and health literacy. Each group completed the same baseline and ending DXA bone density scans, 43-chemistry blood test panels, and 84-item Quality of Life Inventory (QOL. Changes for all subjects were annualized as percent change in BMD from baseline. Using self-reports of adherence, subjects were rank-ordered and dichotomized as “compliant” or “partially compliant” based on the median rating. Comparisons were also made between the treatment groups and two theoretical age-adjusted expected groups: a non-intervention group and a group derived from a review of previously published studies on non-plant sources of calcium.Results: There were no significant differences in baseline BMD between those who volunteered versus those who did not and between those who completed per protocol (PP and those who were lost to attrition. Among subjects completing per protocol, there were no significant differences

  13. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Science.gov (United States)

    2010-07-01

    ...-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... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium...

  14. Calcium and Cancer Prevention: Strengths and Limits of the Evidence

    Science.gov (United States)

    ... calcium carbonate has about 40 percent elemental calcium, meaning that 500 mg of calcium carbonate actually contains ... in this trial also contained vitamin D (400 international units [ IU ]). During ... and calcium in relation to prostate cancer risk among more than 142, ...

  15. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  16. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  17. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p

  18. Calcium and bones

    Science.gov (United States)

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  19. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  20. Get Enough Calcium

    Science.gov (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  1. Visualizing calcium responses to acetylcholine convection along endothelium of arteriolar networks in Cx40BAC-GCaMP2 transgenic mice

    OpenAIRE

    Bagher, Pooneh; Davis, Michael J.; Segal, Steven S.

    2011-01-01

    Acetylcholine evokes endothelium-dependent vasodilation subsequent to a rise in intracellular calcium. Despite widespread application in human and animal studies, calcium responses to intravascular ACh have not been visualized in vivo. Microiontophoresis of ACh in tissue adjacent to an arteriole activates abluminal muscarinic receptors on endothelial cells within a “local” region of diffusion, but it is unknown whether ACh released in such fashion gains access to the flow stream resulting in ...

  2. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

    1984-01-01

    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture, exhausti

  3. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  4. Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

    OpenAIRE

    Sandra Tavares da Silva; Neuza Maria Brunoro Costa; Frederico Souzalima Caldoncelli Franco; Antônio José Natali

    2013-01-01

    OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40) were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day). The animals were kept in individuals metabolic cages a...

  5. Calcium source (image)

    Science.gov (United States)

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  6. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  7. Calcium and bones (image)

    Science.gov (United States)

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  8. Coronary Calcium Scan

    Science.gov (United States)

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  9. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  10. Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Sandra Tavares da Silva

    2013-06-01

    Full Text Available OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40 were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day. The animals were kept in individuals metabolic cages at a temperature of 24°±2ºC, light/dark cycles of 12/12 hours, and deionized water available ad libitum. On the 8th week of the experiment, food consumption was measured and 24-hour urine and 4-day feces were collected to determine calcium balance [Balance=Ca intake-(Urinary Ca+Fecal Ca]. RESULTS: Animals with adequate calcium intake presented higher balances and rates of calcium absorption and retention (p<0.05 than those with inadequate calcium intake, regardless of caffeine intake (p<0.05. Caffeine intake did not affect urinary calcium excretion but increased balance (p<0.05 in the groups with adequate calcium intake. CONCLUSION: Adequate calcium intake attenuated the negative effects of estrogen deficiency and improved calcium balance even in the presence of caffeine.

  11. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  12. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...... of temperature and pH may result in different final structure properties in dairy products such as cheese. A significant amount of calcium remained in the micelles between pH 4.8 and 4.6, this can contribute to the final strength of acid milk gels, such as in yogurt or in cream cheeses. After the gelation point...... enriched dairy products. Calcium gels can be produced by addition of a calcium salt and heat treatment at temperatures higher than 70 oC for several minutes. The combination of heat treatment and calcium addition to milk with pH values between 6.6 and 5.6, will produce calcium milk gels with unique...

  13. Calcium channel blocker overdose

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  14. Fenoprofen calcium overdose

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  15. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  16. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  17. Calcium signaling and epilepsy.

    Science.gov (United States)

    Steinlein, Ortrud K

    2014-08-01

    Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

  18. Smoking, calcium, calcium antagonists, and aging.

    Science.gov (United States)

    Nicita-Mauro, V

    1990-01-01

    Aging is characterized, besides other changes, by a progressive increase in calcium content in the arterial wall, which is enhanced by diabetes mellitus, osteoporosis, arterial hypertension, and tabagism. As to tabagism, experiments in animals have shown that nicotine can increase calcium content of the arterial wall, and clinical studies have demonstrated that cigarette smoking induces peripheral vasoconstriction, with consequent increase in blood pressure levels. In order to study the role of calcium ions in the pathogenesis of the vasoconstrictive lesions caused by "acute" smoking, the author has studied the peripheral vascular effects of the calcium-channel antagonist nifedipine, a dihydropyridine derivative, and calcitonin, a hypocalcemizing hormone which possess vasoactive actions on 12 elderly regular smokers (mean age 65.8 years). The results demonstrated that both nifedipine (10 mg sublingually 20 min before smoking) and salmon calcitonin (100 MRC U/daily intramuscularly for three days) are able to prevent peripheral vasoconstriction evaluated by Doppler velocimetry, as well as the increase of blood pressure induced by smoking. On the basis of our results, the author proposes that cigarette smoking-induced vasoconstriction is a calcium-mediated process, which can be hindered by drugs with calcium antagonist action. PMID:2226675

  19. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  20. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

  1. Dysbalance of astrocyte calcium under hyperammonemic conditions.

    Directory of Open Access Journals (Sweden)

    Nicole Haack

    Full Text Available Increased brain ammonium (NH4(+/NH3 plays a central role in the manifestation of hepatic encephalopathy (HE, a complex syndrome associated with neurological and psychiatric alterations, which is primarily a disorder of astrocytes. Here, we analysed the influence of NH4(+/NH3 on the calcium concentration of astrocytes in situ and studied the underlying mechanisms of NH4(+/NH3-evoked calcium changes, employing fluorescence imaging with Fura-2 in acute tissue slices derived from different regions of the mouse brain. In the hippocampal stratum radiatum, perfusion with 5 mM NH4(+/NH3 for 30 minutes caused a transient calcium increase in about 40% of astrocytes lasting about 10 minutes. Furthermore, the vast majority of astrocytes (∼ 90% experienced a persistent calcium increase by ∼ 50 nM. This persistent increase was already evoked at concentrations of 1-2 mM NH4(+/NH3, developed within 10-20 minutes and was maintained as long as the NH4(+/NH3 was present. Qualitatively similar changes were observed in astrocytes of different neocortical regions as well as in cerebellar Bergmann glia. Inhibition of glutamine synthetase resulted in significantly larger calcium increases in response to NH4(+/NH3, indicating that glutamine accumulation was not a primary cause. Calcium increases were not mimicked by changes in intracellular pH. Pharmacological inhibition of voltage-gated sodium channels, sodium-potassium-chloride-cotransporters (NKCC, the reverse mode of sodium/calcium exchange (NCX, AMPA- or mGluR5-receptors did not dampen NH4(+/NH3-induced calcium increases. They were, however, significantly reduced by inhibition of NMDA receptors and depletion of intracellular calcium stores. Taken together, our measurements show that sustained exposure to NH4(+/NH3 causes a sustained increase in intracellular calcium in astrocytes in situ, which is partly dependent on NMDA receptor activation and on release of calcium from intracellular stores. Our study

  2. Protein kinase C interaction with calcium: a phospholipid-dependent process.

    LENUS (Irish Health Repository)

    Bazzi, M D

    1990-08-21

    The calcium-binding properties of calcium- and phospholipid-dependent protein kinase C (PKC) were investigated by equilibrium dialysis in the presence and the absence of phospholipids. Calcium binding to PKC displayed striking and unexpected behavior; the free proteins bound virtually no calcium at intracellular calcium concentrations and bound limited calcium (about 1 mol\\/mol of PKC) at 200 microM calcium. However, in the presence of membranes containing acidic phospholipids, PKC bound at least eight calcium ions per protein. The presence of 1 microM phorbol dibutyrate (PDBu) in the dialysis buffer had little effect on these calcium-binding properties. Analysis of PKC-calcium binding by gel filtration under equilibrium conditions gave similar results; only membrane-associated PKC bound significant amounts of calcium. Consequently, PKC is a member of what may be a large group of proteins that bind calcium in a phospholipid-dependent manner. The calcium concentrations needed to induce PKC-membrane binding were similar to those needed for calcium binding (about 40 microM calcium at the midpoint). However, the calcium concentration required for PKC-membrane binding was strongly influenced by the phosphatidylserine composition of the membranes. Membranes with higher percentages of phosphatidylserine required lower concentrations of calcium. These properties suggested that the calcium sites may be generated at the interface between PKC and the membrane. Calcium may function as a bridge between PKC and phospholipids. These studies also suggested that calcium-dependent PKC-membrane binding and PKC function could be regulated by a number of factors in addition to calcium levels and diacylglycerol content of the membrane.

  3. Dietary habits of calcium stone formers.

    Science.gov (United States)

    Martini, L A; Heilberg, I P; Cuppari, L; Medeiros, F A; Draibe, S A; Ajzen, H; Schor, N

    1993-08-01

    1. Since dietary factors are known to be related to nephrolithiasis, calcium stone-forming (CSF) patients were evaluated in terms of calcium, total protein of both animal and plant origin, carbohydrate and energy intakes, on the basis of 72-h dietary records during the week plus 24-h dietary records during the week-end. 2. The data for 77 calcium stone formers (57 with absorptive hypercalciuria and 20 with renal hypercalciuria) were compared to those for 29 age-matched healthy subjects. The body mass index of the CSF group was higher than that of healthy subjects (P < 0.05). Consumption of all nutrients was similar for both groups during the week but week-end dietary records for CSF showed higher calcium intake (586 +/- 38 vs 438 +/- 82 mg/day, P < 0.05), protein to body weight ratio (1.2 +/- 0.1 vs 1.0 +/- 0.5 g kg-1 day-1, P < 0.05) and animal protein (56 +/- 3 vs 40 +/- 3 g/day, P < 0.05) when compared with healthy subjects. 3. Comparison of hypercalciuria subtypes (renal hypercalciuria and absorptive hypercalciuria) did not indicate any difference in calcium or energy intake between groups, either during the week or during the week-end. However, the absorptive hypercalciuric group presented higher protein and animal protein consumption during the week-end. 4. These data suggest a low calcium intake in this population, even by stone formers. The higher animal protein consumption by our calcium stone formers observed during week-ends seems to be more important than calcium intake for stone formation. PMID:8298515

  4. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  5. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  6. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  7. GRP40介导游离脂肪酸对葡萄糖刺激的胰岛素分泌和β细胞内钙离子浓度的变化%GPR40 mediates the effects of FFAs on glucose stimulated insulin secretion and the change of intracellular calcium concentration in pancreatic β cells

    Institute of Scientific and Technical Information of China (English)

    张莹; 程桦; 徐明彤; 张少玲; 黎峰; 杨川; 严励; 李焱

    2009-01-01

    目的 探讨G蛋白耦联受体40(GPR40)是否介导游离脂肪酸(FFAs)短期、长期作用对小鼠胰岛NIT-1 β细胞葡萄糖刺激的胰岛素分泌(GSIS)及胞内钙离子浓度的影响.方法 利用siRNA技术抑制GPR40在NIT-1细胞的表达,ELISA法检测棕榈酸、油酸短期(2 h)、长期(48 h)干预对NIT-1细胞GSIS的影响,激光共聚焦显微镜下观察GSIS过程中细胞内钙离子的变化.结果 FFAs短期干预促进空转染组、对照siRNA转染组GSIS水平(P<0.01),而对GPR40 siRNA组GSIS无明显影响,该组细胞GSIS水平明显低于空转染组和对照siRNA转染组(P<0.01).FFAs长期干预明显抑制空转染组、对照siRNA转染组细胞GSIS水平,对GPR40 siRNA组GSIS无明显影响.空转染组、对照siRNA组GSIS水平低于GPR40siRNA组(P<0.05).激光共聚焦显微镜结果显示,在GSIS过程中,FFAs短期干预后,GPR40 siRNA组胞内钙离子浓度峰值明显低于对照siRNA组(棕榈酸:5.10 vs 7.02,油酸:4.27 vs 6.21,均P<0.05);而FFAs长期干预后,GPR40 siRNA组胞内钙离子浓度峰值明显高于对照siRNA组(棕榈酸:3.24 vs 1.21,油酸:2.83 vs 1.18,均P<0.05).结论 GPR40介导FFAs对GSIS和胞内钙离子浓度变化的短期刺激和长期抑制作用.%Objective To investigate whether G-protein coupled receptor 40(GPR40)mediates short-term and long-term effects of free fatty acids (FFAs) on glucose stimulated insulin secretion (GSIS) and the change of [Ca2+]i in mouse insulinoma NIT-1 cells.Methods The expression of GPR40 in NIT-1 cells was inhibited by siRNA.The short-term and long-term effects of saturated (palmitate) or unsaturated (oleate) fatty acids on GSIS in NIT-1 cells transfected with GPR40 siRNA were examined.Insulin was measured by ELISA.The change in intracellular calcium concentration was observed by laser confocal scanning microscopy after NIT-1 cells were incubated with Fluo-3/AM.Results The short-term treatment of FFAs increased GSIS from NIT-1 cells transfected

  8. Intervention effects of atorvastatin calcium tablets on soluble CD40 ligand and C-reactive protein in patients with cardiac angina%阿托伐他汀钙片对心绞痛患者血清可溶性CD40配体与C反应蛋白的干预研究

    Institute of Scientific and Technical Information of China (English)

    王庆玲; 杨永全

    2011-01-01

    Objective To investigate the intervention of level of atorvastatin calcium tablets (lipitor) on soluble CD40 (CD40L) and high sensitivity C-reactive protein (hs-CRP) in patients with angina.Methods 65 patients with coronary heart disease were divided into stable angina (SA group,n= 30) and unstable angina (UA group,n= 35).The vein blood was collected in the hospitalized morning,2,4,6 weeks after treatment and serum levels of hs-CRP and CD40L were measured and compared between the two groups.Results The levels of soluable CD40L [(20.52± 2.91)μg/L] and CRP [(7.96±1.69) mg/L] in UA group were higher than SA group [(7.96±-1.35) tg/L and ( 1.58 ± 0.91 ) mg/L] (t = 21.705、18.493,both P< 0.05) before treatment,and after treatment,their levels in the two groups were significantly lower than pre-treatment (P<0.01).Conclusions CD40L and hs-CRP may involved in the pathophysiology of unstable angina process and can be used as an indicator reflecting vulnerable plaque.Lipitor might enhance stability of atherosclerotic plaque and prevent acute coronary events by reducing levels of CD40L and hs-CRP.%目的 探讨阿托伐他汀钙片对心绞痛患者血清可溶性CD40配体(CD40L)与高敏C反应蛋白(hs-CRP)的干预作用.方法 65例冠心病患者,其中稳定型心绞痛患者30例(SA组),不稳定型心绞痛患者35例(UA组),所有患者于入院当天清晨、治疗后2、4、6周静脉血,测定血清hsCRP、血清可溶性CD40L水平,并对两组结果进行比较.结果 治疗前UA组血清可溶性CD40L、hs-CRP浓度分别为(20.52±2.91)μg/L、(7.96±1.69) mg/L,明显高于SA组(7.96±1.35)μg/L、(1.58±0.91) mg/L(t=21.705、18.493,均P<0.05),而两组治疗后血清可溶性CD40L、hs-CRP浓度均较治疗前明显降低(均P<0.01).结论 血清可溶性CD40L、hs-CRP参与了不稳定型心绞痛的病理生理过程,可以作为反映易损斑块的指标,阿托伐他汀钙片可通过降低血清可溶性CD40L、hs-CRP而加强粥样硬化斑块的稳定性.

  9. 40 CFR 415.311 - Specialized definitions.

    Science.gov (United States)

    2010-07-01

    ... AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Hydroxide Production..., the general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401...

  10. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  11. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine;

    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...

  12. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  13. 40 CFR 63.11524 - Am I subject to this subpart?

    Science.gov (United States)

    2010-07-01

    ... chrome, standard ferromanganese, silicomanganese, ferromanganese silicon, calcium carbide or other..., ferrosilicon, ferrotitanium using the aluminum reduction process, ferrovanadium, ferromolybdenum, calcium... a permit under 40 CFR part 70 or 40 CFR part 71, provided you are not otherwise required by law...

  14. Diversity of calcium speciation in leaves of Primulina species (Gesneriaceae

    Directory of Open Access Journals (Sweden)

    Qingwen Qi

    2014-07-01

    Full Text Available Primulina is a genus containing typical “stone plants” or “cave plants” that show a high degree of edaphic specialization in the karst limestone regions of southwest China. Most species of the genus occur only on calcareous soils developed from carbonate bedrock, while a few species are found only on the red soil developed from the Danxia landform or acidic soil developed from sandshale bedrock. The aim of this study is to investigate the diversity and characteristics of calcium absorption and storage in Primulina from different soil substrates. Calcium in leaves was determined for plants sampled from 15 populations representing 11 Primulina species occurring on calcareous soil, red soil or acid soil. We analyzed the main types of calcium found in leaves, and compared the calcium content within and among species from different soil types. The results revealed a general high level of leaf calcium content in Primulina species compared with other plants from the karst regions of southwest China. However, we found a significant difference in calcium content among Primulina species from different soil types, with high average calcium content (2,285.6 mg/kg in Primulina from calcareous soil relative to low levels present in Primulina from both acid soil (1,379.3 mg/kg and Danxia red soil (1,329.1 mg/kg. The main form of calcium stored in most Primulina species (9 out of 11 was pectate calcium, which accounted for 31.6–64.2% of the total calcium in the leaves. In contrast, for two species, P. linearifolia and P. medica, which grow on soil with a pH > 8, the main calcium form was soluble calcium, which accounted for about 40% of the total calcium in plant leaves. In addition, differences in calcium amount and type were recorded within species from either the same or different soil types. These results suggest that there is variation in calcium speciation found in Primulina at both interspecific and intraspecific levels. Our findings provide a

  15. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Science.gov (United States)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  16. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified.

  17. Children's Bone Health and Calcium

    Science.gov (United States)

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  18. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  19. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  20. Calcium aluminate in alumina

    Science.gov (United States)

    Altay, Arzu

    The properties of ceramic materials are determined not only by the composition and structure of the phases present, but also by the distribution of impurities, intergranular films and second phases. The phase distribution and microstructure both depend on the fabrication techniques, the raw materials used, the phase-equilibrium relations, grain growth and sintering processes. In this dissertation research, various approaches have been employed to understand fundamental phenomena such as grain growth, impurity segregation, second-phase formation and crystallization. The materials system chosen was alumina intentionally doped with calcium. Atomic-scale structural analyses of grain boundaries in alumina were carried on the processed samples. It was found that above certain calcium concentrations, CA6 precipitated as a second phase at all sintering temperatures. The results also showed that abnormal grain growth can occur after precipitation and it is not only related to the calcium level, but it is also temperature dependent. In order to understand the formation mechanism of CA6 precipitates in calcium doped alumina samples, several studies have been carried out using either bulk materials or thin films The crystallization of CA2 and CA6 powders has been studied. Chemical processing techniques were used to synthesize the powders. It was observed that CA2 powders crystallized directly, however CA6 powders crystallized through gamma-Al 2O3 solid solution. The results of energy-loss near-edge spectrometry confirmed that gamma-Al2O3 can dissolve calcium. Calcium aluminate/alumina reaction couples have also been investigated. All reaction couples were heat treated following deposition. It was found that gamma-Al2O3 was formed at the interface as a result of the interfacial reaction between the film and the substrate. gamma-Al 2O3 at the interface was stable at much higher temperatures compared to the bulk gamma-Al2O3 formed prior to the CA6 crystallization. In order to

  1. Calcium intake and prostate cancer among African Americans: effect modification by vitamin D receptor calcium absorption genotype.

    Science.gov (United States)

    Rowland, Glovioell W; Schwartz, Gary G; John, Esther M; Ingles, Sue Ann

    2012-01-01

    High dietary intake of calcium has been classified as a probable cause of prostate cancer, although the mechanism underlying the association between dietary calcium and prostate cancer risk is unclear. The vitamin D receptor (VDR) is a key regulator of calcium absorption. In the small intestine, VDR expression is regulated by the CDX-2 transcription factor, which binds a polymorphic site in the VDR gene promoter. We examined VDR Cdx2 genotype and calcium intake, assessed by a food frequency questionnaire, in 533 African-American prostate cancer cases (256 with advanced stage at diagnosis, 277 with localized stage) and 250 African-American controls who participated in the California Collaborative Prostate Cancer Study. We examined the effects of genotype, calcium intake, and diet-gene interactions by conditional logistic regression. Compared with men in the lowest quartile of calcium intake, men in the highest quartile had an approximately twofold increased risk of localized and advanced prostate cancer (odds ratio [OR] = 2.20, 95% confidence interval [CI] = 1.40, 3.46), with a significant dose-response. Poor absorbers of calcium (VDR Cdx2 GG genotype) had a significantly lower risk of advanced prostate cancer (OR = 0.41, 95% CI = 0.19, 0.90). The gene-calcium interaction was statistically significant (p = 0.03). Among men with calcium intake below the median (680 mg/day), carriers of the G allele had an approximately 50% decreased risk compared with men with the AA genotype. These findings suggest a link between prostate cancer risk and high intestinal absorption of calcium.

  2. Calcium signaling in taste cells.

    Science.gov (United States)

    Medler, Kathryn F

    2015-09-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

  3. Physicochemical properties of calcium polycarbophil, a water-absorbing polymer.

    Science.gov (United States)

    Yamada, T; Kitayama, M; Yamazaki, M; Nagata, O; Tamaj, I; Tsuji, A

    1996-07-01

    The physicochemical properties of calcium polycarbophil were examined. Calcium polycarbophil was decalcified rapidly under acidic conditions, affording polycarbophil. Polycarbophil absorbed about 10 times its own weight of water under acidic conditions, but the swelling ratio markedly increased at above pH 4.0 and reached 70 times the initial weight under neutral conditions. The swelling of polycarbophil was not affected by non-ionic osmolarity, but was affected by ionic strength, showing a decrease with increase of ionic strength. Monovalent metal ions such as sodium and potassium ions in gastrointestinal fluid did not reduce the equilibrium swelling of polycarbophil, but divalent ions such as calcium and magnesium ions did. However, calcium ion only slightly reduced the equilibrium swelling under sodium-rich conditions. The viscosity (as an indicator of fluidity) of polycarbophil was larger than that of CMC-Na at every shear rate and polymer content examined.

  4. Dose-dependent ATP depletion and cancer cell death following calcium electroporation, relative effect of calcium concentration and electric field strength

    DEFF Research Database (Denmark)

    Hansen, Emilie Louise; Sozer, Esin Bengisu; Romeo, Stefania;

    2015-01-01

    BACKGROUND: Electroporation, a method for increasing the permeability of membranes to ions and small molecules, is used in the clinic with chemotherapeutic drugs for cancer treatment (electrochemotherapy). Electroporation with calcium causes ATP (adenosine triphosphate) depletion and cancer cell.......28 kV/cm (SW780), reduced to 1.40 and 1.15 kV/cm (respectively) with 1 mM calcium (lower EC50 for higher calcium concentrations). Quinacrine fluorescence intensity of calcium-electroporated U937 cells was one third lower than in controls (pelectroporation dose......-dependently reduced cell survival and intracellular ATP. Increasing extracellular calcium allows the use of a lower electric field. GENERAL SIGNIFICANCE: This study supports the use of calcium electroporation for treatment of cancer and possibly lowering the applied electric field in future trials....

  5. Fruit Calcium: Transport and Physiology

    Directory of Open Access Journals (Sweden)

    Bradleigh eHocking

    2016-04-01

    Full Text Available Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact fruit development, physical traits and disease susceptibility through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to ripening and the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g. blossom end rot in tomatoes or bitter pit in apples. This review works towards an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved

  6. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  7. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  8. Effect of Indole Butyric Acid on the Transportation of Stored Calcium in Malus hupehensis Rhed. Seedling

    Institute of Scientific and Technical Information of China (English)

    LI Jia; YANG Hong-qiang; YAN Tian-li; SHU Huai-rui

    2006-01-01

    Calcium (Ca) plays an important role in the metabolism of higher plants. Recently, research on Ca2+ in plants has been focused especially at the cellular and molecular levels. Uptake, transport, and distribution are also very important for Ca to accomplish its function at the whole-plant level. In this experiment, one-year-old apple seedlings (M. hupehensis Rehd.) were investigated to determine the distribution of stored Ca, the different forms of Ca, and Ca2+-ATPase activity after treatment with indole butyric acid (IBA). The results showed that the total Ca measured in mature leaves and Ca2+-ATPase activity in tender leaves were higher compared with those in the control (CK). Calcium nitrate and calcium chloride (ALe-Ca) and calcium phosphate and calcium carbonate (HAC-Ca) decreased in both mature leaves and shoots,whereas water-soluble calcium (H2O-Ca), calcium pectate (NaCl-Ca), and calcium oxalate (HCl-Ca) increased. The percentage of active calcium, calcium pectate, and water-soluble calcium increased, whereas the percentage of calcium phosphate and calcium carbonate decreased. When treated with IBA, calcium fractions and percentage of the different forms of Ca was enhanced in 40 part per million (ppm) IBA compared with 20 ppm IBA and water. The results indicated that IBA increased the percentage of both active calcium (NaCl-Ca and H2O-Ca) in tender shoots and boosted the transportation of stored Ca in plants. IBA promoted Ca2+-ATPase activity and Ca2+ uptake in tender shoots of M. hupehensis. It can improve the total Ca contents and the relative percentage of Ca.

  9. Calcium signaling mediates cold sensing in insect tissues.

    Science.gov (United States)

    Teets, Nicholas M; Yi, Shu-Xia; Lee, Richard E; Denlinger, David L

    2013-05-28

    The ability to rapidly respond to changes in temperature is a critical adaptation for insects and other ectotherms living in thermally variable environments. In a process called rapid cold hardening (RCH), insects significantly enhance cold tolerance following brief (i.e., minutes to hours) exposure to nonlethal chilling. Although the ecological relevance of RCH is well-established, the underlying physiological mechanisms that trigger RCH are poorly understood. RCH can be elicited in isolated tissues ex vivo, suggesting cold-sensing and downstream hardening pathways are governed by brain-independent signaling mechanisms. We previously provided preliminary evidence that calcium is involved in RCH, and here we firmly establish that calcium signaling mediates cold sensing in insect tissues. In tracheal cells of the freeze-tolerant goldenrod gall fly, Eurosta solidaginis, chilling to 0 °C evoked a 40% increase in intracellular calcium concentration as determined by live-cell confocal imaging. Downstream of calcium entry, RCH conditions significantly increased the activity of calcium/calmodulin-dependent protein kinase II (CaMKII) while reducing phosphorylation of the inhibitory Thr306 residue. Pharmacological inhibitors of calcium entry, calmodulin activation, and CaMKII activity all prevented ex vivo RCH in midgut and salivary gland tissues, indicating that calcium signaling is required for RCH to occur. Similar results were obtained for a freeze-intolerant species, adults of the flesh fly, Sarcophaga bullata, suggesting that calcium-mediated cold sensing is a general feature of insects. Our results imply that insect tissues use calcium signaling to instantly detect decreases in temperature and trigger downstream cold-hardening mechanisms.

  10. Assessment of food calcium radioprotection effectiveness against cesium-137, added alone and with iodine-131

    International Nuclear Information System (INIS)

    New fish product with addition of food calcium had radioprotective properties, resulted in decreased cesium-137 content in organs and tissues of animals by 40-60% and lesser changes in differential blood count and biochemical indexes of blood serum

  11. Scattering lengths of calcium and barium isotopes

    OpenAIRE

    Dammalapati, U.; Willmann, L.; Knoop, S.

    2011-01-01

    We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba), in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed 40Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that ...

  12. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears that during the origin and early evolution of life the Ca2+ ion was given a unique opportunity to be used in several biological processes because of its unusual physical and chemical properties.

  13. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  14. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid

    2013-07-01

    Full Text Available Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  15. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

    Full Text Available Rightly stressed by prof. Wolfgang Walz in the Preface to the series Neuromethods series, the “careful application of methods is probably the most important step in the process of scientific inquiry”. Thus, I strongly suggest to all those interested in calcium signaling and especially to the new-comers in the hot topic of neuroscience (which has so much space even in science-society debate for its implications in legal issues and in the judge-decision process to take profit from this so well edited book. I am saying this since prof. Verkhratsky and prof. Petersen......

  16. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  17. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  18. Effect of calcium source on structure and properties of sol-gel derived bioactive glasses.

    Science.gov (United States)

    Yu, Bobo; Turdean-Ionescu, Claudia A; Martin, Richard A; Newport, Robert J; Hanna, John V; Smith, Mark E; Jones, Julian R

    2012-12-18

    The aim was to determine the most effective calcium precursor for synthesis of sol-gel hybrids and for improving homogeneity of sol-gel bioactive glasses. Sol-gel derived bioactive calcium silicate glasses are one of the most promising materials for bone regeneration. Inorganic/organic hybrid materials, which are synthesized by incorporating a polymer into the sol-gel process, have also recently been produced to improve toughness. Calcium nitrate is conventionally used as the calcium source, but it has several disadvantages. Calcium nitrate causes inhomogeneity by forming calcium-rich regions, and it requires high temperature treatment (>400 °C) for calcium to be incorporated into the silicate network. Nitrates are also toxic and need to be burnt off. Calcium nitrate therefore cannot be used in the synthesis of hybrids as the highest temperature used in the process is typically 40-60 °C. Therefore, a different precursor is needed that can incorporate calcium into the silica network and enhance the homogeneity of the glasses at low (room) temperature. In this work, calcium methoxyethoxide (CME) was used to synthesize sol-gel bioactive glasses with a range of final processing temperatures from 60 to 800 °C. Comparison is made between the use of CME and calcium chloride and calcium nitrate. Using advanced probe techniques, the temperature at which Ca is incorporated into the network was identified for 70S30C (70 mol % SiO(2), 30 mol % CaO) for each of the calcium precursors. When CaCl(2) was used, the Ca did not seem to enter the network at any of the temperatures used. In contrast, Ca from CME entered the silica network at room temperature, as confirmed by X-ray diffraction, (29)Si magic angle spinning nuclear magnetic resonance spectroscopy, and dissolution studies. CME should be used in preference to calcium salts for hybrid synthesis and may improve homogeneity of sol-gel glasses.

  19. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  20. 40 CFR 98.190 - Definition of the source category.

    Science.gov (United States)

    2010-07-01

    .... (a) Lime manufacturing plants (LMPs) engage in the manufacture of a lime product (e.g., calcium oxide, high-calcium quicklime, calcium hydroxide, hydrated lime, dolomitic quicklime, dolomitic hydrate, or... in 40 CFR 63.7081(a)(1). (b) This source category includes all LMPs unless the LMP is located at...

  1. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000490.htm Calcium, vitamin D, and your bones To use the sharing ... and maintain strong bones. How Much Calcium and Vitamin D Do I Need? Amounts of calcium are ...

  2. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download PDFs ... helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  3. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    OpenAIRE

    Choksi Krishna; Shenoy Ashoka M; A. R. Shabharaya; Lala Minaxi

    2011-01-01

    The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg) and calcium gluconate (5 mg/kg) were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg) to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate cou...

  4. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... in the char conversion process. Comprehensive global equilibrium calculations predicted important characteristics of the inorganic ash residue. Equilibrium calculations predict the formation of liquid salt if sufficient amounts of Ca are added and according to experiments as well as calculations calcium binds...

  5. Analytical models of calcium binding in a calcium channel

    International Nuclear Information System (INIS)

    The anomalous mole fraction effect of L-type calcium channels is analyzed using a Fermi like distribution with the experimental data of Almers and McCleskey [J. Physiol. 353, 585 (1984)] and the atomic resolution model of Lipkind and Fozzard [Biochemistry 40, 6786 (2001)] of the selectivity filter of the channel. Much of the analysis is algebraic, independent of differential equations. The Fermi distribution is derived from the configuration entropy of ions and water molecules with different sizes, different valences, and interstitial voids between particles. It allows us to calculate potentials and distances (between the binding ion and the oxygen ions of the glutamate side chains) directly from the experimental data using algebraic formulas. The spatial resolution of these results is comparable with those of molecular models, but of course the accuracy is no better than that implied by the experimental data. The glutamate side chains in our model are flexible enough to accommodate different types of binding ions in different bath conditions. The binding curves of Na+ and Ca2+ for [CaCl2] ranging from 10−8 to 10−2 M with a fixed 32 mM background [NaCl] are shown to agree with published Monte Carlo simulations. The Poisson-Fermi differential equation—that includes both steric and correlation effects—is then used to obtain the spatial profiles of energy, concentration, and dielectric coefficient from the solvent region to the filter. The energy profiles of ions are shown to depend sensitively on the steric energy that is not taken into account in the classical rate theory. We improve the rate theory by introducing a steric energy that lumps the effects of excluded volumes of all ions and water molecules and empty spaces between particles created by Lennard-Jones type and electrostatic forces. We show that the energy landscape varies significantly with bath concentrations. The energy landscape is not constant

  6. Evolution of the Calcium Paradigm: The Relation between Vitamin D, Serum Calcium and Calcium Absorption

    Directory of Open Access Journals (Sweden)

    Borje E. Christopher Nordin

    2010-09-01

    Full Text Available Osteoporosis is the index disease for calcium deficiency, just as rickets/osteomalacia is the index disease for vitamin D deficiency, but there is considerable overlap between them. The common explanation for this overlap is that hypovitaminosis D causes malabsorption of calcium which then causes secondary hyperparathyroidism and is effectively the same thing as calcium deficiency. This paradigm is incorrect. Hypovitaminosis D causes secondary hyperparathyroidism at serum calcidiol levels lower than 60 nmol/L long before it causes malabsorption of calcium because serum calcitriol (which controls calcium absorption is maintained until serum calcidiol falls below 20 nmol/L. This secondary hyperparathyroidism, probably due to loss of a “calcaemic” action of vitamin D on bone first described in 1957, destroys bone and explains why vitamin D insufficiency is a risk factor for osteoporosis. Vitamin D thus plays a central role in the maintenance of the serum (ionised calcium, which is more important to the organism than the preservation of the skeleton. Bone is sacrificed when absorbed dietary calcium does not match excretion through the skin, kidneys and bowel which is why calcium deficiency causes osteoporosis in experimental animals and, by implication, in humans.

  7. Sensitivity to calcium intake in calcium stone forming patients.

    Science.gov (United States)

    Heilberg, I P; Martini, L A; Draibe, S A; Ajzen, H; Ramos, O L; Schor, N

    1996-01-01

    The absorptive or renal origin of hypercalciuria can be discriminated using an acute oral calcium load test (ACLT). Of 86 patients with calcium oxalate kidney stones, 28 (23%) were found to be hypercalciuric (HCa) and 58 (67%) normocalciuric (NCa) on their customary free diet, containing 542 +/- 29 mg/day (mean +/- SE) of calcium. Since the apparently normal 24-hour calcium excretion of many calcium stone formers (CSF) may be due to a combination of high calcium absorption with moderately low calcium intake, all patients were investigated by ACLT. Of 28 HCa patients, 13 (46%) were classified as absorptive (AH) and 15 (54%) as renal hypercalciuria (RH). Of the 58 NCa patients, 38 (65%) presented features of intestinal hyperabsorption and were therefore designated as AH-like, and 20 (35%) as RH-like. To further elucidate the role of dietary calcium in these CSF, a chronic calcium load test (CCLT), consisting of 1 g/day of oral Ca for 7 days, was designed. A positive response to the CCLT was considered to occur when urinary calcium (uCa) was > or = 4 mg/ kg/24 h on the 7th day. Among NCa patients, 29% of AH-like subjects responded to the CCLT and 71% did not; 50% of RH-like subjects also responded and 50% did not. In HCa patients, 85% of AH and 67% of RH subjects maintained uCa > or = 4 mg/kg/24 h after the CCLT and 15% of AH and 23% of RH subjects did not. However, a significant additional increase in mean uCa was not observed among HCa patients. All patients were submitted to a second evaluation of fasting calciuria (Ca/Cr). A modification of this parameter was noticed in 89% of RH-like and 78% of RH patients. In conclusion, these data suggest the presence of subpopulations of patients sensitive or not to calcium intake, regardless of whether the acute response to a calcium overload test suggested AH or RH. The CCLT disclosed dietary hypercalciuria in 21/58 (36%) of previously NCa patients. In these NCa patients, the ACLT may be replaced by the CCLT. The distinction

  8. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    Energy Technology Data Exchange (ETDEWEB)

    Bizzozero, Julien, E-mail: julien.bizzozero@gmail.com; Scrivener, Karen L.

    2015-10-15

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction.

  9. Hybrid calcium phosphate coatings for implants

    Science.gov (United States)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  10. Calcium binding protein-mediated regulation of voltage-gated calcium channels linked to human diseases

    Institute of Scientific and Technical Information of China (English)

    Nasrin NFJATBAKHSH; Zhong-ping FENG

    2011-01-01

    Calcium ion entry through voltage-gated calcium channels is essential for cellular signalling in a wide variety of cells and multiple physiological processes. Perturbations of voltage-gated calcium channel function can lead to pathophysiological consequences. Calcium binding proteins serve as calcium sensors and regulate the calcium channel properties via feedback mechanisms. This review highlights the current evidences of calcium binding protein-mediated channel regulation in human diseases.

  11. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness. PMID:7488645

  12. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  13. Dose-dependent ATP depletion and cancer cell death following calcium electroporation, relative effect of calcium concentration and electric field strength.

    Directory of Open Access Journals (Sweden)

    Emilie Louise Hansen

    Full Text Available Electroporation, a method for increasing the permeability of membranes to ions and small molecules, is used in the clinic with chemotherapeutic drugs for cancer treatment (electrochemotherapy. Electroporation with calcium causes ATP (adenosine triphosphate depletion and cancer cell death and could be a novel cancer treatment. This study aims at understanding the relationship between applied electric field, calcium concentration, ATP depletion and efficacy.In three human cell lines--H69 (small-cell lung cancer, SW780 (bladder cancer, and U937 (leukaemia, viability was determined after treatment with 1, 3, or 5 mM calcium and eight 99 μs pulses with 0.8, 1.0, 1.2, 1.4 or 1.6 kV/cm. Fitting analysis was applied to quantify the cell-killing efficacy in presence of calcium. Post-treatment intracellular ATP was measured in H69 and SW780 cells. Post-treatment intracellular ATP was observed with fluorescence confocal microscopy of quinacrine-labelled U937 cells.Both H69 and SW780 cells showed dose-dependent (calcium concentration and electric field decrease in intracellular ATP (p<0.05 and reduced viability. The 50% effective cell kill was found at 3.71 kV/cm (H69 and 3.28 kV/cm (SW780, reduced to 1.40 and 1.15 kV/cm (respectively with 1 mM calcium (lower EC50 for higher calcium concentrations. Quinacrine fluorescence intensity of calcium-electroporated U937 cells was one third lower than in controls (p<0.0001.Calcium electroporation dose-dependently reduced cell survival and intracellular ATP. Increasing extracellular calcium allows the use of a lower electric field.This study supports the use of calcium electroporation for treatment of cancer and possibly lowering the applied electric field in future trials.

  14. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature

    Directory of Open Access Journals (Sweden)

    K. B. Kale

    2012-12-01

    Full Text Available The CO2 adsorption by calcium zirconate was explored at pre- and post- combustion temperature condition. The several samples of the calcium zirconate were prepared by different methods such as sol-gel, solid-solid fusion, template and micro-emulsion. The samples of the calcium zirconate were characterized by measurement of surface area, alkalinity/acidity, and recording the XRD patterns and SEM images. The CO2 adsorptions by samples of the calcium zirconate were studied in the temperature range 100 to 850 oC and the CO2 adsorptions were observed in the ranges of 6.88 to 40.6 wt % at 600 0C and 8 to 16.82 wt% at in between the temperatures 200 to 300 oC. The effect of Ca/Zr mol ratio in the samples of the calcium zirconate on the CO2 adsorption and alkalinity were discussed. The adsorbed moisture by the samples of the calcium zirconate was found to be useful for the CO2 adsorption. The promoted the samples of the calcium zirconate by K+, Na+, Rb+, Cs+, Ag+ and La3+ showed the increased CO2 adsorption. The exposure time of CO2 on the samples of the calcium zirconate showed the increased CO2 adsorption. The samples of the calcium zirconate were found to be regenerable and reusable several times for the adsorption of CO2 for at the post- and pre-combustion temperature condition. Copyright © 2012 by BCREC Undip. All rights reservedReceived: 23rd June 2012, Revised: 28th August 2012, Accepted: 30th August 2012[How to Cite: K. B. Kale, R. Y. Raskar, V. H. Rane and A. G.  Gaikwad (2012. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 124-136. doi:10.9767/bcrec.7.2.3686.124-136] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3686.124-136 ] | View in 

  15. Calcium Orthophosphates as Bioceramics: State of the Art

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2010-11-01

    Full Text Available In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whether calcium orthophosphate bioceramics were biologically stable once incorporated within the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics—which is able to promote regeneration of bones—was developed. Presently, calcium orthophosphate bioceramics are available in the form of particulates, blocks, cements, coatings, customized designs for specific applications and as injectable composites in a polymer carrier. Current biomedical applications include artificial replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Exploratory studies demonstrate potential applications of calcium orthophosphate bioceramics as scaffolds, drug delivery systems, as well as carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes.

  16. Variability of calcium absorption

    International Nuclear Information System (INIS)

    Variability in calcium absorption was estimated in three groups of normal subjects in whom Ca absorption was measured by standard isotopic-tracer methods at interstudy intervals ranging from 1 to 4 mo. Fifty absorption tests were performed in 22 subjects. Each was done in the morning after an overnight fast with an identical standard breakfast containing a Ca load of approximately 250 mg. Individual fractional absorption values were normalized to permit pooling of the data. The coefficient of variation (CVs) for absorption for the three groups ranged from 10.57 to 12.79% with the size of the CV increasing with interstudy duration. One other published study presenting replicate absorption values was analyzed in a similar fashion and was found to have a CV of absorption of 9.78%. From these data we estimate that when the standard double-isotope method is used to measure Ca absorption there is approximately 10% variability around any given absorption value within an individual human subject and that roughly two-thirds of this represents real biological variability in absorption

  17. Vitamin D does not increase calcium absorption in young women: a randomized clinical trial.

    Science.gov (United States)

    Gallagher, J Christopher; Jindal, Prachi S; Smith, Lynette M

    2014-01-01

    It is commonly said that vitamin D should be used to increase calcium absorption. We tested this statement in a dose-response study of vitamin D on calcium absorption. A total of 198 white and African American women, aged 25 to 45 years, with vitamin D insufficiency, serum 25-hydroxyvitamin D (25OHD) ng/mL, were randomized in a double-blind study to vitamin D3 400, 800, 1600, 2400 IU, or placebo. A calcium supplement was given to increase mean calcium intake at baseline from 706 mg/d to 1031 mg/d. Calcium absorption was measured at baseline and after 12 months using a single isotope method with radiocalcium45 and 100 mg of calcium. Mean baseline serum 25OHD was 13.4 ng/mL (33.5 nmol/L) and increased to 40 ng/mL (100 nmol/L) on the highest dose of 2400 IU. Using a multivariate regression analysis with significant predictors, baseline absorption, calcium intake, and weight, there was no increase in 12-month calcium absorption compared with baseline on any dose of vitamin D in either whites or African Americans. There was no significant relationship between 12-month calcium absorption and final serum 25OHD. In an analysis of calcium absorption and serum 25OHD at baseline, serum 25OHD levels were divided into groups: 0 to 5, 6 to 10, 11 to 15, or 16 to 20 ng/mL. There was no evidence of a threshold decrease in calcium absorption or serum 1,25 dihydroxyvitamin D (1,25(OH)2 D) amongst the lowest groups. Vitamin D doses up to 2400 IU daily did not increase calcium absorption. No threshold level of serum 25OHD for calcium absorption was found at baseline or in the longitudinal study, suggesting that active transport of calcium is saturated at very low serum 25OHD levels ng/mL. There is no need to recommend vitamin D for increasing calcium absorption in normal subjects. Very efficient calcium absorption at very low levels of serum 25OHD explains why people do not develop osteomalacia provided that dietary intakes of calcium and phosphorus are adequate. PMID

  18. Binding of [125I]iodipine to parathyroid cell membranes: Evidence of a dihydropyridine-sensitive calcium channel

    International Nuclear Information System (INIS)

    The parathyroid cell is unusual, in that an increase in extracellular calcium concentrations inhibits PTH release. Calcium channels are glycoproteins that span cell membranes and allow entry of extracellular calcium into cells. We have demonstrated that the calcium channel agonist (+)202-791, which opens calcium channels, inhibits PTH release and that the antagonist (-)202-791, which closes calcium channels, stimulates PTH release. To identify the calcium channels responsible for these effects, we used a radioligand that specifically binds to calcium channels. Bovine parathyroid cell membranes were prepared and incubated under reduced lighting with [125I] iodipine (SA, 2000 Ci/mmol), which recognizes 1,4-dihydropyridine-sensitive calcium channels. Bound ligand was separated from free ligand by rapid filtration through Whatman GF/B filters. Nonspecific binding was measured by the inclusion of nifedipine at 10 microM. Specific binding represented approximately 40% of the total binding. The optimal temperature for [125I] iodipine binding was 4 C, and binding reached equilibrium by 30 min. The equilibrium dissociation constant (Kd) was approximately 550 pM, and the maximum number of binding sites was 780 fmol/mg protein. Both the calcium channel agonist (+)202-791 and antagonist (-)202-791 competitively inhibited [125I] iodipine binding, with 50% inhibition concentrations of 20 and 300 nM, respectively. These data indicate the presence of dihydropyridine-sensitive calcium channels on parathyroid cell membranes

  19. 40 CFR 424.51 - Specialized definitions.

    Science.gov (United States)

    2010-07-01

    ... STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Other Calcium Carbide Furnaces Subcategory § 424.51... definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart....

  20. Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa

    DEFF Research Database (Denmark)

    Blomberg Jensen, Martin; Bjerrum, Poul J; Jessen, Torben E;

    2011-01-01

    BACKGROUND The vitamin D receptor (VDR) is expressed in human spermatozoa, and VDR-knockout mice and vitamin D (VD) deficiency in rodents results in impaired fertility, low sperm counts and a low number of motile spermatozoa. We investigated the role of activated VD (1,25(OH)(2)D(3)) in human...... spermatozoa and whether VD serum levels are associated with semen quality. METHODS Cross-sectional association study of semen quality and VD serum level in 300 men from the general population, and in vitro studies on spermatozoa from 40 men to investigate the effects of VD on intracellular calcium, sperm......M). 1,25(OH)(2)D(3) increased intracellular calcium concentration in human spermatozoa through VDR-mediated calcium release from an intracellular calcium storage, increased sperm motility and induced the acrosome reaction in vitro. CONCLUSIONS 1,25(OH)(2)D(3) increased intracellular calcium...

  1. Mitochondrial calcium uptake.

    Science.gov (United States)

    Williams, George S B; Boyman, Liron; Chikando, Aristide C; Khairallah, Ramzi J; Lederer, W J

    2013-06-25

    Calcium (Ca(2+)) uptake into the mitochondrial matrix is critically important to cellular function. As a regulator of matrix Ca(2+) levels, this flux influences energy production and can initiate cell death. If large, this flux could potentially alter intracellular Ca(2+) ([Ca(2+)]i) signals. Despite years of study, fundamental disagreements on the extent and speed of mitochondrial Ca(2+) uptake still exist. Here, we review and quantitatively analyze mitochondrial Ca(2+) uptake fluxes from different tissues and interpret the results with respect to the recently proposed mitochondrial Ca(2+) uniporter (MCU) candidate. This quantitative analysis yields four clear results: (i) under physiological conditions, Ca(2+) influx into the mitochondria via the MCU is small relative to other cytosolic Ca(2+) extrusion pathways; (ii) single MCU conductance is ∼6-7 pS (105 mM [Ca(2+)]), and MCU flux appears to be modulated by [Ca(2+)]i, suggesting Ca(2+) regulation of MCU open probability (P(O)); (iii) in the heart, two features are clear: the number of MCU channels per mitochondrion can be calculated, and MCU probability is low under normal conditions; and (iv) in skeletal muscle and liver cells, uptake per mitochondrion varies in magnitude but total uptake per cell still appears to be modest. Based on our analysis of available quantitative data, we conclude that although Ca(2+) critically regulates mitochondrial function, the mitochondria do not act as a significant dynamic buffer of cytosolic Ca(2+) under physiological conditions. Nevertheless, with prolonged (superphysiological) elevations of [Ca(2+)]i, mitochondrial Ca(2+) uptake can increase 10- to 1,000-fold and begin to shape [Ca(2+)]i dynamics.

  2. Magnesium supplementation through seaweed calcium extract rather than synthetic magnesium oxide improves femur bone mineral density and strength in ovariectomized rats.

    Science.gov (United States)

    Bae, Yun Jung; Bu, So Young; Kim, Jae Young; Yeon, Jee-Young; Sohn, Eun-Wha; Jang, Ki-Hyo; Lee, Jae-Cheol; Kim, Mi-Hyun

    2011-12-01

    Commercially available seaweed calcium extract can supply high amounts of calcium as well as significant amounts of magnesium and other microminerals. The purpose of this study was to investigate the degree to which the high levels of magnesium in seaweed calcium extract affects the calcium balance and the bone status in ovariectomized rats in comparison to rats supplemented with calcium carbonate and magnesium oxide. A total of 40 Sprague-Dawley female rats (7 weeks) were divided into four groups and bred for 12 weeks: sham-operated group (Sham), ovariectomized group (OVX), ovariectomized with inorganic calcium and magnesium supplementation group (OVX-Mg), and ovariectomized with seaweed calcium and magnesium supplementation group (OVX-SCa). All experimental diets contained 0.5% calcium. The magnesium content in the experimental diet was 0.05% of the diet in the Sham and OVX groups and 0.1% of the diet in the OVX-Mg and OVX-SCa groups. In the calcium balance study, the OVX-Mg and OVX-SCa groups were not significantly different in calcium absorption compared to the OVX group. However, the femoral bone mineral density and strength of the OVX-SCa group were higher than those of the OVX-Mg and OVX groups. Seaweed calcium with magnesium supplementation or magnesium supplementation alone did not affect the serum ALP and CTx levels in ovariectomized rats. In summary, consumption of seaweed calcium extract or inorganic calcium carbonate with magnesium oxide demonstrated the same degree of intestinal calcium absorption, but only the consumption of seaweed calcium extract resulted in increased femoral bone mineral density and strength in ovariectomized rats. Our results suggest that seaweed calcium extract is an effective calcium and magnesium source for improving bone health compared to synthetic calcium and magnesium supplementation.

  3. Calcium isotopes in wine

    Science.gov (United States)

    Holmden, C. E.

    2011-12-01

    The δ 44/40Ca values of bottled wine vary between -0.76% to -1.55% on the seawater scale and correlate weakly with inverse Ca concentration and Mg/Ca ratio, such that the lowest δ 44/40Ca values have the highest Ca concentrations and lowest Mg/Ca ratios. The correlation is notable in the sense that the measured wines include both whites and reds sampled from different wine growing regions of the world, and cover a wide range of quality. Trends among the data yield clues regarding the cause of the observed isotopic fractionation. White wines, and wines generally perceived to be of lower quality, have lower δ 44/40Ca values compared to red wines and wines of generally perceived higher quality. Quality was assessed qualitatively through sensory evaluation, price, and scores assigned by critics. The relationship between δ 44/40Ca and wine quality was most apparent when comparing wines of one varietal from one producer from the same growing region. In the vineyard, wine quality is related to factors such as the tonnage of the crop and the ripeness of the grapes at the time of harvesting, the thickness of the skins for reds, the age of the vines, as well as the place where the grapes were grown (terroir). Quality is also influenced by winemaking practices such as fermentation temperature, duration of skin contact, and barrel ageing. Accordingly, the relationship between δ 44/40Ca and wine quality may originate during grape ripening in the vineyard or during winemaking in the cellar. We tested the grape ripening hypothesis using Merlot grapes sampled from a vineyard in the Okanagan, British Columbia, using sugar content (degrees Brix) as an indicator of ripeness. The grapes were separated into pulp, skin, and pip fractions and were analyzed separately. Thus far, there is no clear evidence for a systematic change in δ 44/40Ca values associated with progressive ripening of grapes in the vineyard. On the day of harvesting, the δ 44/40Ca value of juice squeezed from

  4. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    OpenAIRE

    Ganesan Lavanya; Josephraj Jegan

    2015-01-01

    This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study...

  5. Calcium Orthophosphates as Bioceramics: State of the Art

    OpenAIRE

    Sergey V. Dorozhkin

    2010-01-01

    In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whet...

  6. The influence of chronic administration of calcium carbonate on the bioavailability of oral ciprofloxacin.

    OpenAIRE

    Sahai, J; Healy, D P; Stotka, J; Polk, R E

    1993-01-01

    Six healthy male volunteers participated in a two-period, two-treatment study to determine the effect of chronic calcium carbonate administration on ciprofloxacin bioavailability. There was a mean reduction of 40% in Cmax and 43% in AUC when calcium carbonate was administered with ciprofloxacin, compared with ciprofloxacin alone (P < 0.05). There were no changes in either half-life or tmax. It is therefore recommended that patients being treated with ciprofloxacin for serious infections refra...

  7. Aging and calcium as an environmental factor.

    Science.gov (United States)

    Fujita, T

    1985-12-01

    Calcium deficiency is a constant menace to land-abiding animals, including mammals. Humans enjoying exceptional longevity on earth are especially susceptible to calcium deficiency in old age. Low calcium and vitamin D intake, short solar exposure, decreased intestinal absorption, and falling renal function with insufficient 1,25(OH)2 vitamin D biosynthesis all contribute to calcium deficiency, secondary hyperparathyroidism, bone loss and possibly calcium shift from the bone to soft tissue, and from the extracellular to the intracellular compartment, blunting the sharp concentration gap between these compartments. The consequences of calcium deficiency might thus include not only osteoporosis, but also arteriosclerosis and hypertension due to the increase of calcium in the vascular wall, amyotrophic lateral sclerosis and senile dementia due to calcium deposition in the central nervous system, and a decrease in cellular function, because of blunting of the difference in extracellular-intracellular calcium, leading to diabetes mellitus, immune deficiency and others (Fig. 6). PMID:2943880

  8. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

    Kisiel, Anna; Kłucińska, Katarzyna; Gniadek, Marianna; Maksymiuk, Krzysztof; Michalska, Agata

    2015-11-01

    Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M. PMID:26452839

  9. The effect of compressive loading magnitude on in situ chondrocyte calcium signaling.

    Science.gov (United States)

    Madden, Ryan M J; Han, Sang-Kuy; Herzog, Walter

    2015-01-01

    Chondrocyte metabolism is stimulated by deformation and is associated with structural changes in the cartilage extracellular matrix (ECM), suggesting that these cells are involved in maintaining tissue health and integrity. Calcium signaling is an initial step in chondrocyte mechanotransduction that has been linked to many cellular processes. Previous studies using isolated chondrocytes proposed loading magnitude as an important factor regulating this response. However, calcium signaling in the intact cartilage differs compared to isolated cells. The purpose of this study was to investigate the effect of loading magnitude on chondrocyte calcium signaling in intact cartilage. We hypothesized that the percentage of cells exhibiting at least one calcium signal increases with increasing load. Fully intact rabbit femoral condyle and patellar bone/cartilage samples were incubated in calcium-sensitive dyes and imaged continuously under compressive loads of 10-40 % strain. Calcium signaling was primarily associated with the dynamic loading phase and greatly increased beyond a threshold deformation of about 10 % nominal tissue strain. There was a trend toward more cells exhibiting calcium signaling as loading magnitude increased (p = 0.133). These results provide novel information toward identifying mechanisms underlying calcium-dependent signaling pathways related to cartilage homeostasis and possibly the onset and progression of osteoarthritis.

  10. Measurement of calcium content of gallstones by computed tomography and the relationship between gallbladder function and calcification of gallstones

    Energy Technology Data Exchange (ETDEWEB)

    Yoneda, Masashi; Tamasawa, Naoki; Takebe, Kazuo (Hirosaki Univ. (Japan). School of Medicine); Makino, Isao; Sakuraba, Kiyoshi; Tamura, Toyokazu

    1990-08-01

    To evaluate the relationship between gallbladder function and calcification of gallstones, we studied gallbladder contractility by oral cholecystography, the computed tomography (CT) number of stones for 30 gallstone patients, calcium content of 13 stones operatively extirpated, and the degree of inflammatory change in 13 surgical gallbladder specimens. There was significant correlation between the calcium content and CT numbers of stones, and 1% of the calcium content of gallstone was approximately equal to 40 Hounsfield Units (HU) of the CT number. The calcium content of stones in patients with normal gallbladder contractility was extrapolated to be below 1.5%, while that with poor contractility ranged from 0% to 21%. Additionally there is a possibility that calcium content increases, related to the inflammatory change of gallbladder. Hence our results suggested that measurement of the CT number of stones is useful to evaluate the calcium content of gallstones, and that the gallbladder contractility could be one of the factors to influence calcification of stones. (author).

  11. Calcium release-activated calcium current in rat mast cells.

    Science.gov (United States)

    Hoth, M; Penner, R

    1993-06-01

    1. Whole-cell patch clamp recordings of membrane currents and fura-2 measurements of free intracellular calcium concentration ([Ca2+]i) were used to study the biophysical properties of a calcium current activated by depletion of intracellular calcium stores in rat peritoneal mast cells. 2. Calcium influx through an inward calcium release-activated calcium current (ICRAC) was induced by three independent mechanisms that result in store depletion: intracellular infusion of inositol 1,4,5-trisphosphate (InsP3) or extracellular application of ionomycin (active depletion), and intracellular infusion of calcium chelators (ethylene glycol bis-N,N,N',N'-tetraacetic acid (EGTA) or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)) to prevent reuptake of leaked-out calcium into the stores (passive depletion). 3. The activation of ICRAC induced by active store depletion has a short delay (4-14 s) following intracellular infusion of InsP3 or extracellular application of ionomycin. It has a monoexponential time course with a time constant of 20-30 s and, depending on the complementary Ca2+ buffer, a mean normalized amplitude (at 0 mV) of 0.6 pA pF-1 (with EGTA) and 1.1 pA pF-1 (with BAPTA). 4. After full activation of ICRAC by InsP3 in the presence of EGTA (10 mM), hyperpolarizing pulses to -100 mV induced an instantaneous inward current that decayed by 64% within 50 ms. This inactivation is probably mediated by [Ca2+]i, since the decrease of inward current in the presence of the fast Ca2+ buffer BAPTA (10 mM) was only 30%. 5. The amplitude of ICRAC was dependent on the extracellular Ca2+ concentration with an apparent dissociation constant (KD) of 3.3 mM. Inward currents were nonsaturating up to -200 mV. 6. The selectivity of ICRAC for Ca2+ was assessed by using fura-2 as the dominant intracellular buffer (at a concentration of 2 mM) and relating the absolute changes in the calcium-sensitive fluorescence (390 nm excitation) with the calcium current integral

  12. 40 CFR 415.36 - Pretreatment standards for new sources (PSNS).

    Science.gov (United States)

    2010-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Carbide... works must comply with 40 CFR part 403 and achieve the following pretreatment standards for new...

  13. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  14. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    S.A. Gomes

    2004-09-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  15. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    Gomes S.A.

    2004-01-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  16. Changes in intracellular calcium in brain cells of aged rats

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yunpeng Cao

    2008-01-01

    BACKGROUND: Studies have shown that voltage-dependent calcium influx, and enhancement of certain calcium-dependent processes in neurons, is related to aging. OBJECTIVE: To observe changes in intracellular calcium ([Ca2+]i) in neurons of aged rats, and to compare with young rats. DESIGN, TIME AND SETTING: A randomized control experiment of neurophysiology was performed at the Central Laboratory of School of Pharmaceutical Science, China Medical University from June to August 2004. MATERIALS: Ten male, healthy, Wistar rats, 19 months old, were selected for the aged group. Ten male, 3-month-old, Wistar rats were selected for the young control group. Fura-2/AM was provided by the Institute of Pharmaceutical Research of Chinese Academy of Medical Sciences, and the F-2000 fluorospectrophotometer was a product of Hitachi, Japan. METHODS: Fluorescence Fura-2 spectrophotometer was used to measure [Ca2+]i in acutely dissociated brain cells of aged and young rats. The concentration of extracellular potassium was controlled by adding different volumes of chloridated potassium solution of high concentration. MAIN OUTCOME MEASURES: [Ca2+]i in neurons of young and aged rats in the presence of 1 mmol/L extracellular calcium concentration and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium. Absolute increase of [Ca2+]i in neurons of young and aged rats when extraceUular potassium was 5,10,20, 40 mmol/L. RESULTS: In the presence of 1 mmol/L extracellular Ca2+ and 0 mmol/L (resting state), 5, 10, 20, and 40 mmol/L extracellular potassium, [Ca2+]i in the neurons of aged rats was significantly less than that in young rats (P 0.05). CONCLUSION: The overload of [Ca2+]i in neurons of aged rats is greater than that of young rats under the same circumstances.

  17. The effect of calcium gluconate and other calcium supplements as a dietary calcium source on magnesium absorption in rats.

    Science.gov (United States)

    Chonan, O; Takahashi, R; Yasui, H; Watanuki, M

    1997-01-01

    The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.

  18. Decalcification of calcium polycarbophil in rats.

    Science.gov (United States)

    Yamada, T; Saito, T; Takahara, E; Nagata, O; Tamai, I; Tsuji, A

    1997-03-01

    The in vivo decalcification of calcium polycarbophil was examined. The decalcification ratio of [45Ca]calcium polycarbophil in the stomach after oral dosing to rats was more than 70% at each designated time and quite closely followed in the in vitro decalcification curve, indicating that the greater part of the calcium ion is released from calcium polycarbophil under normal gastric acidic conditions. The residual radioactivity in rat gastrointestine was nearly equal to that after oral administration of either [45Ca]calcium chloride + polycarbophil. The serum level of radioactivity was nearly equal to that after oral dosing of [45Ca]calcium lactate. These results indicate that the greater part of orally administered calcium polycarbophil released calcium ions to produce polycarbophil in vivo.

  19. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results in...

  20. Calcium, vitamin D, and your bones

    Science.gov (United States)

    ... can break easily, even without an obvious injury. Vitamin D helps your body absorb calcium. Eat foods that provide the right amounts of calcium, vitamin D, and protein. This kind of diet will give ...

  1. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

    ... Dairy Dilemma Dairy Dilemma Are You Getting Enough Calcium? You may be avoiding dairy products because of ... But dairy products are a major source of calcium, vitamin D and other nutrients that are important ...

  2. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the store-operated calcium entry or capacitative calcium entry. Capacitative calcium current plays a key role in replenishing calcium stores and activating various physiological processes. Despite considerable efforts, very little is known about the molecular nature of the capacitative channel and the signalling pathway that activates it. This review summarizes our current knowledge about store operated calcium entry and suggests possible hypotheses for its mode of activation.

  3. Gelsolin mediates calcium-dependent disassembly of Listeria actin tails

    Science.gov (United States)

    Larson, Laura; Arnaudeau, Serge; Gibson, Bruce; Li, Wei; Krause, Ryoko; Hao, Binghua; Bamburg, James R.; Lew, Daniel P.; Demaurex, Nicolas; Southwick, Frederick

    2005-01-01

    The role of intracellular Ca2+ in the regulation of actin filament assembly and disassembly has not been clearly defined. We show that reduction of intracellular free Ca2+ concentration ([Ca2+]i) to <40 nM in Listeria monocytogenes-infected, EGFP–actin-transfected Madin–Darby canine kidney cells results in a 3-fold lengthening of actin filament tails. This increase in tail length is the consequence of marked slowing of the actin filament disassembly rate, without a significant change in assembly rate. The Ca2+-sensitive actin-severing protein gelsolin concentrates in the Listeria rocket tails at normal resting [Ca2+]i and disassociates from the tails when [Ca2+]i is lowered. Reduction in [Ca2+]i also blocks the severing activity of gelsolin, but not actin-depolymerizing factor (ADF)/cofilin microinjected into Listeria-infected cells. In Xenopus extracts, Listeria tail lengths are also calcium-sensitive, markedly shortening on addition of calcium. Immunodepletion of gelsolin, but not Xenopus ADF/cofilin, eliminates calcium-sensitive actin-filament shortening. Listeria tail length is also calcium-insensitive in gelsolin-null mouse embryo fibroblasts. We conclude that gelsolin is the primary Ca2+-sensitive actin filament recycling protein in the cell and is capable of enhancing Listeria actin tail disassembly at normal resting [Ca2+]i (145 nM). These experiments illustrate the unique and complementary functions of gelsolin and ADF/cofilin in the recycling of actin filaments. PMID:15671163

  4. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofi-brillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers in-volved in Alzheimer's disease therapy.

  5. 21 CFR 184.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and... Substances Affirmed as GRAS § 184.1210 Calcium oxide. (a) Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. It is produced from calcium carbonate, limestone,...

  6. 21 CFR 184.1185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... 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 may...

  7. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

    Jan, J.-P.; Skriver, Hans Lomholt

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure...

  8. Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

    This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

  9. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  10. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2227 Calcium silicate. (a) Product. Calcium silicate....

  11. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  12. 21 CFR 582.5210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.5210 Section 582.5210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance...

  13. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve po

  14. 21 CFR 582.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.1210 Section 582.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is...

  15. 21 CFR 582.6185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  16. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  18. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.5217 Section 582.5217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  19. GABA(A) Increases Calcium in Subventricular Zone Astrocyte-Like Cells Through L- and T-Type Voltage-Gated Calcium Channels

    DEFF Research Database (Denmark)

    Young, Stephanie Z; Platel, Jean-Claude; Nielsen, Jakob V;

    2010-01-01

    induced Ca(2+) increases in 40-50% of SVZ astrocytes. GABA(A)-induced Ca(2+) increases were prevented with nifedipine and mibefradil, blockers of L- and T-type voltage-gated calcium channels (VGCC). The L-type Ca(2+) channel activator BayK 8644 increased the percentage of GABA(A)-responding astrocyte...

  20. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille;

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation...... offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...... electroporation and electrochemotherapy. METHODS: The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore...

  1. Calcium Carbonate versus Sevelamer Hydrochloride as Phosphate Binders after Long-Term Disease Progression in 5/6 Nephrectomized Rats

    Directory of Open Access Journals (Sweden)

    Suvi Törmänen

    2014-01-01

    Full Text Available Our aim was to compare the effects of calcium carbonate and sevelamer-HCl treatments on calcium-phosphate metabolism and renal function in 5/6 nephrectomized (NX rats so that long-term disease progression preceded the treatment. After 15-week progression, calcium carbonate (3.0%, sevelamer-HCl (3.0%, or control diets (0.3% calcium were given for 9 weeks. Subtotal nephrectomy reduced creatinine clearance (−40%, plasma calcidiol (−25%, and calcitriol (−70% and increased phosphate (+37%, parathyroid hormone (PTH (11-fold, and fibroblast growth factor-23 (FGF-23 (4-fold. In NX rats, calcium carbonate diet increased plasma (+20% and urinary calcium (6-fold, reduced plasma phosphate (−50% and calcidiol (−30%, decreased creatinine clearance (−35% and FGF 23 (−85%, and suppressed PTH without influencing blood pH. In NX rats, sevelamer-HCl increased urinary calcium (4-fold and decreased creatinine clearance (−45%, PTH (−75%, blood pH (by 0.20 units, plasma calcidiol (−40%, and calcitriol (−65%. Plasma phosphate and FGF-23 were unchanged. In conclusion, when initiated after long-term progression of experimental renal insufficiency, calcium carbonate diet reduced plasma phosphate and FGF-23 while sevelamer-HCl did not. The former induced hypercalcemia, the latter induced acidosis, while both treatments reduced vitamin D metabolites and deteriorated renal function. Thus, delayed initiation influences the effects of these phosphate binders in remnant kidney rats.

  2. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  3. Computational study of a calcium release-activated calcium channel

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

    The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

  4. Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction.

    Science.gov (United States)

    Combes, C; Bareille, R; Rey, C

    2006-11-01

    The feasibility of making calcium carbonate-calcium phosphate (CaCO(3)-CaP) mixed cements, comprising at least 40% (w/w) CaCO(3) in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline CaCO(3) phases with metastable amorphous or crystalline CaP powders in aqueous medium. The cements set within at most 1 h at 37 degrees C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the metastable CaP phase with part or almost all of the metastable CaCO(3) phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO(3) with a higher solubility than that of the apatite formed in the well-developed CaP cements might be of interest to increase resorption rates in biomedical cement and favors its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO(3)-CaP mixed cement compositions.

  5. Contribution to the study of calcium metabolism in the deficiency of testosterone

    International Nuclear Information System (INIS)

    Kinetic parameters of calcium mobilization in rats were determined to estimate the role of testosterone in the metabolism of this ion. Calcium multicompartimental theory was combined to and used in measurements of metabolic balance (for 45CaCl2 or 40CaCl2). Three groups of 60 day old rats were used: G I-control; G II-castrated; G III-castrated and treated with testosterone propionate. Data were obtained from measurements of Ca++ in samples of plasma, feces and urine. Balance studies suggest that calcium level in blood plasma remained constant in all groups, the increase of bone reabsorption in groups II and III being counterbalanced by the elevation of the urinary excrection. This result implies the equilibrium occurring at renal level. Intestinal calcium absorption remained the same in the three groups of animals, indicating that testosterone has no consistent effect at intestinal level. The increase of total calcium in feces of groups II and III arises from a great endogenous secretion. A significant negative balance of calcium was also observed in these groups. This fact permits the conclusion that in the absence of testosterone the organism doesn't retain calcium efficiently. (M.A.)

  6. Cytoplasmic calcium levels in protoplasts from the cap and elongation zone of maize roots

    Science.gov (United States)

    Kiss, H. G.; Evans, M. L.; Johnson, J. D.

    1991-01-01

    Calcium has been implicated as a key component in the signal transduction process of root gravitropism. We measured cytoplasmic free calcium in protoplasts isolated from the elongation zone and cap of primary roots of light-grown, vertically oriented seedlings of Zea mays L. Protoplasts were loaded with the penta-potassium salts of fura-2 and indo-1 by incubation in acidic solutions of these calcium indicators. Loading increased with decreasing pH but the pH dependence was stronger for indo-1 than for fura-2. In the case of fura-2, loading was enhanced only at the lowest pH (4.5) tested. Dyes loaded in this manner were distributed predominantly in the cytoplasm as indicated by fluorescence patterns. As an alternative method of loading, protoplasts were incubated with the acetoxymethylesters of fura-2 and indo-1. Protoplasts loaded by this method exhibited fluorescence both in the cytoplasm and in association with various organelles. Cytoplasmic calcium levels measured using spectrofluorometry, were found to be 160 +/- 40 nM and 257 +/- 27 nM, respectively, in populations of protoplasts from the root cap and elongation zone. Cytoplasmic free calcium did not increase upon addition of calcium to the incubation medium, indicating that the passive permeability to calcium was low.

  7. Calcium biofortification and bioaccessibility in soilless "baby leaf" vegetable production.

    Science.gov (United States)

    D'Imperio, Massimiliano; Renna, Massimiliano; Cardinali, Angela; Buttaro, Donato; Serio, Francesco; Santamaria, Pietro

    2016-12-15

    Calcium is an essential nutrient for human health, because it is a structural component and takes part in a variety of biological processes. The aim of this study was to increase Ca content of baby leaf vegetables (BLV: basil, mizuna, tatsoi and endive), as fresh-cut products. For the production of biofortified BLV, a floating system with two level of Ca (100 and 200mgL(-1)) in the nutrient solution was used. In addition, the assessment of bioaccessibility of Ca, by in vitro digestion process, was performed. In all vegetables, the Ca biofortification (200mgL(-1)) caused a significant Ca enrichment (9.5% on average) without affecting vegetables growth, oxalate contents and marketable quality. Calcium bioaccessibility ranged from 25% (basil) to 40% (endive) but the biofortified vegetables showed more bioaccessible Ca. These results underline the possibility to obtain Ca biofortified BLV by using agronomic approaches. PMID:27451166

  8. Relation of urinary calcium and magnesium excretion to blood pressure

    DEFF Research Database (Denmark)

    Kesteloot, Hugo; Tzoulaki, Ioanna; Brown, Ian J;

    2011-01-01

    of calcium and magnesium in 2 cross-sectional studies. The International Study of Macro- and Micro-Nutrients and Blood Pressure (INTERMAP) comprised 4,679 persons aged 40-59 years from 17 population samples in China, Japan, the United Kingdom, and the United States, and the International Cooperative Study...... on Salt, Other Factors, and Blood Pressure (INTERSALT) comprised 10,067 persons aged 20-59 years from 52 samples around the world. Timed 24-hour urine collections, BP measurements, and nutrient data from four 24-hour dietary recalls (INTERMAP) were collected. In multiple linear regression analyses......) of higher urinary calcium excretion (associations were smaller for diastolic BP) in INTERMAP. Qualitatively similar associations were observed in INTERSALT analyses. Associations between magnesium excretion and BP were small and nonsignificant for most of the models examined. The present data suggest...

  9. Store-operated calcium signaling in neutrophils.

    Science.gov (United States)

    Clemens, Regina A; Lowell, Clifford A

    2015-10-01

    Calcium signals in neutrophils are initiated by a variety of cell-surface receptors, including formyl peptide and other GPCRs, FcRs, and integrins. The predominant pathway by which calcium enters immune cells is termed SOCE, whereby plasma membrane CRAC channels allow influx of extracellular calcium into the cytoplasm when intracellular ER stores are depleted. The identification of 2 key families of SOCE regulators, STIM calcium "sensors" and ORAI calcium channels, has allowed for genetic manipulation of SOCE pathways and provided valuable insight into the molecular mechanism of calcium signaling in immune cells, including neutrophils. This review focuses on our current knowledge of the molecules involved in neutrophil SOCE and how study of these molecules has further informed our understanding of the role of calcium signaling in neutrophil activation.

  10. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

    Full Text Available The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg and calcium gluconate (5 mg/kg were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate could not show significant anti-inflammatory activity on their own in acute as well as subacute inflammation models. Aspirin at sub-anti-inflammatory dose (50mg/Kg when co-administered along with calcium salts produced the significant anti-inflammatory response which was comparable to anti-inflammatory response of aspirin at therapeutic dose (200mg/Kg. Also co-adminostration minimized the gastro-toxicity of aspirin.

  11. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    International Nuclear Information System (INIS)

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H3PO4/P2O5/Et3PO4 followed by acid–base reaction with Ca(OAc)2 to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for 1H, and 31P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO4 or CaCl2 were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min

  12. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  13. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  14. Self-diffusion of calcium ions in soda-lime and slag glasses

    International Nuclear Information System (INIS)

    The self-diffusion coefficients of calcium ions in 16Na2O.12CaO.72SiO2(wt%) glass and 40CaO.20Al2O3.40SiO2(wt%) slag glass at temperatures near and below transition point have been measured employing radio-isotope 45Ca. The concentration gradient of radio-activity in surface layer of glass samples after diffusion annealing was determined by counting the residual activity with a GM-tube counter on the surface by progressively chemical etching away the material in steps of about 1 micron meter. It was found that the self-diffusion coefficients of calcium ions in both glasses below the transition point were of the order of 10-14 -- 10-16 cm2/s, suggesting that the mobility of calcium ions was extremely small in the solid glasses. The activation energy for diffusion of calcium ions in solid glasses was about 60 kcal/mol, which seemed to be reasonable in comparison with the electrostatic binding energy between cation and oxygen ion. The self-diffusion coefficients of calcium ions in the slag glass agrees closely with those of oxygen ions below the transition point, while the self-diffusion coefficients of calcium ions in the soda-lime glass are greater by one order of magnitude than those of oxygen ions in the same glass. The difference of diffusion behavior of calcium ions in the slag and the soda-lime glasses may be attributed to action of alkali ions on the mobility of calcium ions. (auth.)

  15. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  16. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  17. Calcium channel as a potential anticancer agent.

    Science.gov (United States)

    Kriazhev, L

    2009-11-01

    Anticancer treatment in modern clinical practices includes chemotherapy and radiation therapy with or without surgical interventions. Efficiency of both methods varies greatly depending on cancer types and stages. Besides, chemo- and radiotherapy are toxic and damaging that causes serious side effects. This fact prompts the search for alternative methods of antitumor therapy. It is well known that prolonged or high increase of intracellular calcium concentration inevitably leads to the cell death via apoptosis or necrosis. However, stimulation of cell calcium level by chemical agents is hardly achievable because cells have very sophisticated machinery for maintaining intracellular calcium in physiological ranges. This obstacle can be overridden, nevertheless. It was found that calcium channels in so called calcium cells in land snails are directly regulated by extracellular calcium concentration. The higher the concentration the higher the calcium intake is through the channels. Bearing in mind that extracellular/intracellular calcium concentration ratio in human beings is 10,000-12,000 fold the insertion of the channel into cancer cells would lead to fast and uncontrollable by the cells calcium intake and cell death. Proteins composing the channel may be extracted from plasma membrane of calcium cells and sequenced by mass-spectrometry or N-terminal sequencing. Either proteins or corresponding genes could be used for targeted delivery into cancer cells.

  18. Clogging and Cementation Caused by Calcium or Iron Biogrouts

    Science.gov (United States)

    Ivanov, V.; Chu, J.; Naeimi, M.

    2012-12-01

    Chemical grouts are often used to reduce the hydraulic conductivity of soil for seepage control purposes. However, chemical grouts can be expensive and environmentally unfriendly. Therefore, two new biogrouts were tested for their bioclogging and biocementation properties. The first was calcium-based biogrout, which contained urease-producing bacteria, calcium chloride and urea for the crystallization of calcite due to enzymatic hydrolysis of urea. The second was iron-based biogrout, which consisted of urease-producing bacteria, ferric chelate, and urea for the precipitation of ferric hydroxide and carbonate due to enzymatic hydrolysis of urea. The permeability of sand (P, 10^-5 m/s), treated with calcium-based biogrout, linearly decreased as a function of the content of precipitated calcium (C, % w/w) according to the following equation: P = 5.1 - 4.0 C. Meanwhile, the permeability of sand treated with iron-based biogrout dropped to 2.7x10^-6 m/s at content of precipitated iron (F, % w/w) about 0.35 % w/w , by the equation: P = 5.1 - 14.6 F , and then slowly decreased to 1.4x10^-7 m/s at content of precipitated iron 1.8% w/w by the following equation: P = 0.36 - 0.23F. Both biogrouts have approximately same efficiency in the reduction of permeability of sand to low values. However, the mechanisms of bioclogging are probably different because the reduction of permeability by calcium-based biogrout was described by linear function of precipitated calcium but the reduction of permeability by iron-based biogrout showed two steps of the clogging. Different functions and mechanisms were related probably to the different type of precipitates. The images of biogrouted sand samples show that calcium-based biogrout produced white amorphous or crystallised calcium carbonate, while iron-based biogrout produced gel-like brown precipitate without visible crystals. The unconfined compressive strengths of the sand treated with different biogrouts (Y, kPa) increased by power

  19. Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients

    Directory of Open Access Journals (Sweden)

    Bading Hilmar

    2007-07-01

    Full Text Available Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events.

  20. Altered calcium signaling in cancer cells.

    Science.gov (United States)

    Stewart, Teneale A; Yapa, Kunsala T D S; Monteith, Gregory R

    2015-10-01

    It is the nature of the calcium signal, as determined by the coordinated activity of a suite of calcium channels, pumps, exchangers and binding proteins that ultimately guides a cell's fate. Deregulation of the calcium signal is often deleterious and has been linked to each of the 'cancer hallmarks'. Despite this, we do not yet have a full understanding of the remodeling of the calcium signal associated with cancer. Such an understanding could aid in guiding the development of therapies specifically targeting altered calcium signaling in cancer cells during tumorigenic progression. Findings from some of the studies that have assessed the remodeling of the calcium signal associated with tumorigenesis and/or processes important in invasion and metastasis are presented in this review. The potential of new methodologies is also discussed. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

  1. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

    Suneelkumar, Chinni; Datta, Krithika; Manali R Srinivasan; Kumar, Sampath T

    2008-01-01

    Calcium phosphate ceramics like hydroxyapatite and β -tricalcium phosphate (β -TCP) possess mineral composition that closely resembles that of the bone. They can be good bone substitutes due to their excellent biocompatibility. Biphasic calcium phosphate is a bone substitute which is a mixture of hydroxyapatite and β -tricalcium phosphate in fixed ratios. Studies have demonstrated the osteoconductive potential of this composition. This paper highlights the clinical use of biphasic calcium pho...

  2. Overbased Calcium sulfonate Detergent Technology Overview

    Institute of Scientific and Technical Information of China (English)

    MA Qing-gao; MUIR Ronald J.

    2009-01-01

    Overbased calcium sulfonate is used widely as detergent in automotive and marine lubricants, as well as various industrial oil applications. In this paper, the process to produce overbased calcium sulfonate is overviewed. The sulfonate structure and molecular weight and its molecular weight distribution, the enclosed calcium carbonate nanoparticle size and crystalline structure, properties of the carrier oil, all influence its properties, such as stability, viscosity, and detergency of the system.

  3. [Calcium carbide of different crystal formation synthesized by calcium carbide residue].

    Science.gov (United States)

    Lu, Zhong-yuan; Kang, Ming; Jiang, Cai-rong; Tu, Ming-jing

    2006-04-01

    To recycle calcium carbide residue effectively, calcium carbide of different crystal form, including global aragonite, calcite and acicular calcium carbide was synthesized. Both the influence of pretreatment in the purity of calcium carbide, and the influence of temperatures of carbonization reaction, release velocity of carbon dioxide in the apparition of calcium carbide of different crystal form were studied with DTA-TG and SEM. The result shows that calcium carbide residue can take place chemistry reaction with ammonia chlorinate straight. Under the condition that pH was above 7, the purity of calcium carbide was above 97%, and the whiteness was above 98. Once provided the different temperatures of carbonization reaction and the proper release velocity of carbon dioxide, global aragonite, calcite and acicular calcium carbide were obtained.

  4. Calcium binding proteins and calcium signaling in prokaryotes.

    Science.gov (United States)

    Domínguez, Delfina C; Guragain, Manita; Patrauchan, Marianna

    2015-03-01

    With the continued increase of genomic information and computational analyses during the recent years, the number of newly discovered calcium binding proteins (CaBPs) in prokaryotic organisms has increased dramatically. These proteins contain sequences that closely resemble a variety of eukaryotic calcium (Ca(2+)) binding motifs including the canonical and pseudo EF-hand motifs, Ca(2+)-binding β-roll, Greek key motif and a novel putative Ca(2+)-binding domain, called the Big domain. Prokaryotic CaBPs have been implicated in diverse cellular activities such as division, development, motility, homeostasis, stress response, secretion, transport, signaling and host-pathogen interactions. However, the majority of these proteins are hypothetical, and only few of them have been studied functionally. The finding of many diverse CaBPs in prokaryotic genomes opens an exciting area of research to explore and define the role of Ca(2+) in organisms other than eukaryotes. This review presents the most recent developments in the field of CaBPs and novel advancements in the role of Ca(2+) in prokaryotes.

  5. Osteoblasts detect pericellular calcium concentration increase via neomycin-sensitive voltage gated calcium channels.

    Science.gov (United States)

    Sun, Xuanhao; Kishore, Vipuil; Fites, Kateri; Akkus, Ozan

    2012-11-01

    The mechanisms underlying the detection of critically loaded or micro-damaged regions of bone by bone cells are still a matter of debate. Our previous studies showed that calcium efflux originates from pre-failure regions of bone matrix and MC3T3-E1 osteoblasts respond to such efflux by an increase in the intracellular calcium concentration. The mechanisms by which the intracellular calcium concentration increases in response to an increase in the pericellular calcium concentration are unknown. Elevation of the intracellular calcium may occur via release from the internal calcium stores of the cell and/or via the membrane bound channels. The current study applied a wide range of pharmaceutical inhibitors to identify the calcium entry pathways involved in the process: internal calcium release from endoplasmic reticulum (ER, inhibited by thapsigargin and TMB-8), calcium receptor (CaSR, inhibited by calhex), stretch-activated calcium channel (SACC, inhibited by gadolinium), voltage-gated calcium channels (VGCC, inhibited by nifedipine, verapamil, neomycin, and ω-conotoxin), and calcium-induced-calcium-release channel (CICRC, inhibited by ryanodine and dantrolene). These inhibitors were screened for their effectiveness to block intracellular calcium increase by using a concentration gradient induced calcium efflux model which mimics calcium diffusion from the basal aspect of cells. The inhibitor(s) which reduced the intracellular calcium response was further tested on osteoblasts seeded on mechanically loaded notched cortical bone wafers undergoing damage. The results showed that only neomycin reduced the intracellular calcium response in osteoblasts, by 27%, upon extracellular calcium stimulus induced by concentration gradient. The inhibitory effect of neomycin was more pronounced (75% reduction in maximum fluorescence) for osteoblasts seeded on notched cortical bone wafers loaded mechanically to damaging load levels. These results imply that the increase in

  6. Sintering of calcium phosphate bioceramics.

    Science.gov (United States)

    Champion, E

    2013-04-01

    Calcium phosphate ceramics have become of prime importance for biological applications in the field of bone tissue engineering. This paper reviews the sintering behaviour of these bioceramics. Conventional pressureless sintering of hydroxyapatite, Ca10(PO4)6(OH)2, a reference compound, has been extensively studied. Its physico-chemistry is detailed. It can be seen as a competition between two thermally activated phenomena that proceed by solid-state diffusion of matter: densification and grain growth. Usually, the objective is to promote the first and prevent the second. Literature data are analysed from sintering maps (i.e. grain growth vs. densification). Sintering trajectories of hydroxyapatite produced by conventional pressureless sintering and non-conventional techniques, including two-step sintering, liquid phase sintering, hot pressing, hot isostatic pressing, ultrahigh pressure, microwave and spark plasma sintering, are presented. Whatever the sintering technique may be, grain growth occurs mainly during the last step of sintering, when the relative bulk density reaches 95% of the maximum value. Though often considered very advantageous, most assisted sintering techniques do not appear very superior to conventional pressureless sintering. Sintering of tricalcium phosphate or biphasic calcium phosphates is also discussed. The chemical composition of calcium phosphate influences the behaviour. Similarly, ionic substitutions in hydroxyapatite or in tricalcium phosphate create lattice defects that modify the sintering rate. Depending on their nature, they can either accelerate or slow down the sintering rate. The thermal stability of compounds at the sintering temperature must also be taken into account. Controlled atmospheres may be required to prevent thermal decomposition, and flash sintering techniques, which allow consolidation at low temperature, can be helpful. PMID:23212081

  7. Altered calcium signaling following traumatic brain injury

    Directory of Open Access Journals (Sweden)

    John Thomas Weber

    2012-04-01

    Full Text Available Cell death and dysfunction after traumatic brain injury (TBI is caused by a primary phase, related to direct mechanical disruption of the brain, and a secondary phase which consists of delayed events initiated at the time of the physical insult. Arguably, the calcium ion contributes greatly to the delayed cell damage and death after TBI. A large, sustained influx of calcium into cells can initiate cell death signaling cascades, through activation of several degradative enzymes, such as proteases and endonucleases. However, a sustained level of intracellular free calcium is not necessarily lethal, but the specific route of calcium entry may couple calcium directly to cell death pathways. Other sources of calcium, such as intracellular calcium stores, can also contribute to cell damage. In addition, calcium-mediated signal transduction pathways in neurons may be perturbed following injury. These latter types of alterations may contribute to abnormal physiology in neurons that do not necessarily die after a traumatic episode. This review provides an overview of experimental evidence that has led to our current understanding of the role of calcium signaling in death and dysfunction following TBI.

  8. Calcium supplements: do they help or harm?

    Science.gov (United States)

    Manson, Joann E; Bassuk, Shari S

    2014-01-01

    Current recommendations for calcium intake call for 1,000 mg per day for women ages 19-50 and 1,200 mg per day for women over age 50 to ensure bone health. Given recent concerns that calcium supplements may raise risk for cardiovascular disease and kidney stones, women should aim to meet this recommendation primarily by eating a calcium-rich diet and taking calcium supplements only if needed to reach the RDA goal (often only approximately 500 mg per day in supplements is required). PMID:23880796

  9. Peroxisome is a reservoir of intracellular calcium.

    Science.gov (United States)

    Raychaudhury, Bikramjit; Gupta, Shreedhara; Banerjee, Shouvik; Datta, Salil C

    2006-07-01

    We have examined fura 2-loaded purified peroxisomes under confocal microscope to prove that this mammalian organelle is a store of intracellular calcium pool. Presence of calcium channel and vanadate sensitive Ca(2+)-ATPase in the purified peroxisomal membrane has been demonstrated. We have further observed that machineries to maintain calcium pool in this mammalian organelle are impaired during infection caused by Leishmania donovani. Results reveal that peroxisomes have a merit to play a significant role in the metabolism of intracellular calcium. PMID:16713100

  10. Unexpectedly large charge radii of neutron-rich calcium isotopes

    CERN Document Server

    Garcia Ruiz, R F; Blaum, K; Ekström, A; Frömmgen, N; Hagen, G; Hammen, M; Hebeler, K; Holt, J D; Jansen, G R; Kowalska, M; Kreim, K; Nazarewicz, W; Neugart, R; Neyens, G; Nörtershäuser, W; Papenbrock, T; Papuga, J; Schwenk, A; Simonis, J; Wendt, K A; Yordanov, D T

    2016-01-01

    Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain ‘magic’ numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known calcium isotopes have been successfully described by nuclear theory, it is still a challenge to predict the evolution of their charge radii. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-...

  11. Unexpectedly large charge radii of neutron-rich calcium isotopes

    Science.gov (United States)

    Garcia Ruiz, R. F.; Bissell, M. L.; Blaum, K.; Ekström, A.; Frömmgen, N.; Hagen, G.; Hammen, M.; Hebeler, K.; Holt, J. D.; Jansen, G. R.; Kowalska, M.; Kreim, K.; Nazarewicz, W.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Papenbrock, T.; Papuga, J.; Schwenk, A.; Simonis, J.; Wendt, K. A.; Yordanov, D. T.

    2016-06-01

    Despite being a complex many-body system, the atomic nucleus exhibits simple structures for certain `magic’ numbers of protons and neutrons. The calcium chain in particular is both unique and puzzling: evidence of doubly magic features are known in 40,48Ca, and recently suggested in two radioactive isotopes, 52,54Ca. Although many properties of experimentally known calcium isotopes have been successfully described by nuclear theory, it is still a challenge to predict the evolution of their charge radii. Here we present the first measurements of the charge radii of 49,51,52Ca, obtained from laser spectroscopy experiments at ISOLDE, CERN. The experimental results are complemented by state-of-the-art theoretical calculations. The large and unexpected increase of the size of the neutron-rich calcium isotopes beyond N = 28 challenges the doubly magic nature of 52Ca and opens new intriguing questions on the evolution of nuclear sizes away from stability, which are of importance for our understanding of neutron-rich atomic nuclei.

  12. Calcium Imaging Perspectives in Plants

    Directory of Open Access Journals (Sweden)

    Chidananda Nagamangala Kanchiswamy

    2014-03-01

    Full Text Available The calcium ion (Ca2+ is a versatile intracellular messenger. It provides dynamic regulation of a vast array of gene transcriptions, protein kinases, transcription factors and other complex downstream signaling cascades. For the past six decades, intracellular Ca2+ concentration has been significantly studied and still many studies are under way. Our understanding of Ca2+ signaling and the corresponding physiological phenomenon is growing exponentially. Here we focus on the improvements made in the development of probes used for Ca2+ imaging and expanding the application of Ca2+ imaging in plant science research.

  13. Calcium Absorption from Fortified Ice Cream Formulations Compared with Calcium Absorption from Milk

    OpenAIRE

    van der Hee, Regine M.; Miret, Silvia; Slettenaar, Marieke; Duchateau, Guus S.M.J.E.; Rietveld, Anton G.; Wilkinson, Joy E.; Quail, Patricia J.; Berry, Mark J.; Dainty, Jack R.; Teucher, Birgit; Fairweather-Tait, Susan J

    2009-01-01

    Objective Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing the important role of calcium-rich food products. We have designed a calcium-fort...

  14. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    OpenAIRE

    A Rathod; Bonny, O; Guessous, I; Suter, P M; Conen, D; Erne, P; Binet, I; Gabutti, L; Gallino, A; Muggli, F; Hayoz, D; Pechere-Bertschi, A; Paccaud, F.; Burnier, M.; Bochud, M

    2015-01-01

    BACKGROUND AND OBJECTIVES: Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dep...

  15. Calcium

    Science.gov (United States)

    ... for lunch; and beans, salsa, taco sauce, and cheese for dinner. Create mini-pizzas by topping whole-wheat English muffins or bagels with pizza sauce and low-fat mozzarella or soy cheese. Try whole-grain crackers with low-fat cheese ...

  16. Calcium

    Science.gov (United States)

    ... tingling in the fingers, convulsions, and abnormal heart rhythms that can lead to death if not corrected. ... that includes weight-bearing physical activity (such as walking and running). Osteoporosis is a disease of the ...

  17. Effect of lowering dietary calcium intake on fractional whole body calcium retention

    Energy Technology Data Exchange (ETDEWEB)

    Dawson-Hughes, B.; Stern, D.T.; Shipp, C.C.; Rasmussen, H.M.

    1988-07-01

    Although fractional calcium absorption is known to vary inversely with calcium intake, the extent and timing of individual hormonal and calcium absorption responses to altered calcium intake have not been defined. We measured fractional whole body retention of orally ingested /sup 47/Ca, an index of calcium absorption, in nine normal women after they had eaten a 2000-mg calcium diet for 8 weeks and a 300-mg calcium diet for 1, 2, 4, and 8 weeks. After the diet change, serum intact PTH (32.2% increase; P = 0.005), serum 1,25-dihydroxyvitamin D (1,25-(OH)2D; 43.8% increase; P = 0.003), and fractional whole body calcium retention (42.8% increase; P = 0.004) increased within 1 week. Although the PTH and calcium retention responses remained fairly constant throughout the low calcium intake period, serum 1,25-(OH)2D concentrations declined toward baseline after week 1. Thus, the late increase in calcium retention may have resulted from calcium absorption that was independent of 1,25-(OH)2D stimulation.

  18. Protein intake and calcium absorption – Potential role of the calcium sensor receptor

    Science.gov (United States)

    Dietary protein induces calcium excretion but the source of this calcium is unclear. Evidence from short-term studies indicates that protein promotes bone resorption, but many epidemiologic studies do not corroborate this. Evidence is also mixed on weather protein promotes calcium absorption. Stud...

  19. Inhibitory efficacy of calcium cyanamide on the pathogens of replant diseases in strawberry

    Institute of Scientific and Technical Information of China (English)

    WANG Lijing; HU Tongle; JI Lijing; CAO Keqiang

    2007-01-01

    Replant diseases in strawberry caused by Rhizoctonia solani,Fusarium oxysporum and Verticillium dahliae are serious problems for its sustainable production under continuous cropping.This research studied the inhibitory effect of calcium cyanamide on pathogenic fungi in Petri dishes and on sterilized soil.Results indicated that calcium cyanamide had an obvious inhibitory effect on three pathogens on potato dextrose agar (PDA) plates.Among them,the inhibitory effect on Rhizoctonia solani was the highest.As the concentrations of calcium cyanamide was increased from 0.1 to 10 mg/mL,the inhibition rate on mycelial growth increased from -1.43% to 100%.Inhibitory effects on Fusarium oxysporum and Verticillium dahliae also existed on Petri dishes but to a lesser extent.Similar results were also observed in sterilized soil.When the concentration of calcium cyanamide in sterilized soil was 0.1%,the inhibitory effect on Fusarium oxysporum and Verticillium dahliae was 68.46% and 54.46%,respectively.The inhibitive effect of calcium cyanamide on Fusariurn oxysporum and Verticillium dahliae increased quickly as the soil moisture changed from 10% to 40% for Verticillium dahliae and from 10% to 60% forFusarium oxysporum.This indicated that the inhibitive effect of calcium cyanamide could be influenced greatly by the moisture content in the soil.

  20. Calcium signaling in pluripotent stem cells.

    Science.gov (United States)

    Apáti, Ágota; Pászty, Katalin; Erdei, Zsuzsa; Szebényi, Kornélia; Homolya, László; Sarkadi, Balázs

    2012-04-28

    Pluripotent stem cells represent a new source of biological material allowing the exploration of signaling phenomena during normal cell development and differentiation. Still, the calcium signaling pathways and intracellular calcium responses to various ligands or stress conditions have not been sufficiently explored as yet in embryonic or induced pluripotent stem cells and in their differentiated offspring. This is partly due to the special culturing conditions of these cell types, the rapid morphological and functional changes in heterogeneous cell populations during early differentiation, and methodological problems in cellular calcium measurements. In this paper, we review the currently available data in the literature on calcium signaling in pluripotent stem cells and discuss the potential shortcomings of these studies. Various assay methods are surveyed for obtaining reliable data both in undifferentiated embryonic stem cells and in specific, stem cell-derived human tissues. In this paper, we present the modulation of calcium signaling in human embryonic stem cells (hESC) and in their derivates; mesenchymal stem cell like (MSCl) cells and cardiac tissues using the fluorescent calcium indicator Fluo-4 and confocal microscopy. LPA, trypsin and angiotensin II were effective in inducing calcium signals both in HUES9 and MSCl cells. Histamine and thrombin induced calcium signal exclusively in the MSCl cells, while ATP was effective only in HUES9 cells. There was no calcium signal evoked by GABA, even at relatively high concentrations. In stem cell-derived cardiomyocytes a rapid increase in the beating rate and an increase of the calcium signal peaks could be observed after the addition of adrenaline, while verapamil led to a strong decrease in cellular calcium and stopped spontaneous contractions in a relaxed state.

  1. Presynaptic calcium signalling in cerebellar mossy fibres

    Directory of Open Access Journals (Sweden)

    Louiza B Thomsen

    2010-02-01

    Full Text Available Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A TTX-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none tetrodotoxin (TTX -sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than one second affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.

  2. Hypercalcemia Associated with Calcium Supplement Use: Prevalence and Characteristics in Hospitalized Patients

    Science.gov (United States)

    Machado, Maria C.; Bruce-Mensah, Araba; Whitmire, Melanie; Rizvi, Ali A.

    2015-01-01

    Background: The ingestion of large amounts of milk and antacids to treat peptic ulcer disease was a common cause of hypercalcemia in the past (the “milk-alkali syndrome”). The current popularity of calcium and supplements has given rise to a similar problem. Objectives: To evaluate the prevalence and characteristics of hypercalcemia induced by calcium intake (“calcium supplement syndrome”; or CSS) in hospitalized patients. Methods: We conducted a retrospective; electronic health record (EHR)-based review of patients with hypercalcemia over a 3-year period. Diagnosis of CSS was based on the presence of hypercalcemia; a normal parathyroid hormone (PTH) level; renal insufficiency; metabolic alkalosis; a history of calcium intake; and documented improvement with treatment. Results: Of the 72 patients with non-PTH mediated hypercalcemia; 15 (20.8%) satisfied all the criteria for the diagnosis of CSS. Calcium; vitamin D; and multivitamin ingestion were significantly associated with the diagnosis (p values < 0.0001; 0.014; and 0.045 respectively); while the presence of hypertension; diabetes; and renal insufficiency showed a trend towards statistical significance. All patients received intravenous fluids; and six (40%) received calcium-lowering drugs. The calcium level at discharge was normal 12 (80%) of patients. The mean serum creatinine and bicarbonate levels decreased from 2.4 and 35 mg/dL on admission respectively; to 1.6 mg/dL and 25.6 mg/dL at discharge respectively. Conclusion: The widespread use of calcium and vitamin D supplementation can manifest as hypercalcemia and worsening of kidney function in susceptible individuals. Awareness among health care professionals can lead to proper patient education regarding these health risks. PMID:26239247

  3. Hypercalcemia Associated with Calcium Supplement Use: Prevalence and Characteristics in Hospitalized Patients

    Directory of Open Access Journals (Sweden)

    Maria C. Machado

    2015-03-01

    Full Text Available Background: The ingestion of large amounts of milk and antacids to treat peptic ulcer disease was a common cause of hypercalcemia in the past (the “milk-alkali syndrome”. The current popularity of calcium and supplements has given rise to a similar problem. Objectives: To evaluate the prevalence and characteristics of hypercalcemia induced by calcium intake (“calcium supplement syndrome”; or CSS in hospitalized patients. Methods: We conducted a retrospective; electronic health record (EHR-based review of patients with hypercalcemia over a 3-year period. Diagnosis of CSS was based on the presence of hypercalcemia; a normal parathyroid hormone (PTH level; renal insufficiency; metabolic alkalosis; a history of calcium intake; and documented improvement with treatment. Results: Of the 72 patients with non-PTH mediated hypercalcemia; 15 (20.8% satisfied all the criteria for the diagnosis of CSS. Calcium; vitamin D; and multivitamin ingestion were significantly associated with the diagnosis (p values < 0.0001; 0.014; and 0.045 respectively; while the presence of hypertension; diabetes; and renal insufficiency showed a trend towards statistical significance. All patients received intravenous fluids; and six (40% received calcium-lowering drugs. The calcium level at discharge was normal 12 (80% of patients. The mean serum creatinine and bicarbonate levels decreased from 2.4 and 35 mg/dL on admission respectively; to 1.6 mg/dL and 25.6 mg/dL at discharge respectively. Conclusion: The widespread use of calcium and vitamin D supplementation can manifest as hypercalcemia and worsening of kidney function in susceptible individuals. Awareness among health care professionals can lead to proper patient education regarding these health risks.

  4. An Intracellular Calcium Oscillations Model Including Mitochondrial Calcium Cycling

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-Min; LIU Zeng-Rong

    2005-01-01

    @@ Calcium is a ubiquitous second messenger. Mitochondria contributes significantly to intracellular Ca2+ dynamics.The experiment of Kaftan et al. [J. Biol. Chem. 275(2000) 25465] demonstrated that inhibiting mitochondrial Ca2+ uptake can reduce the frequency of cytosolic Ca2+ concentration oscillations of gonadotropes. By considering the mitochondrial Ca2+ cycling we develop a three-variable model of intracellular Ca2+ oscillations based on the models of Atri et al. [Biophys. J. 65 (1993) 1727] and Falcke et al. [Biophys. J. 77 (1999) 37]. The model reproduces the fact that mitochondrial Ca2+ cycling increases the frequency of cytosolic Ca2+ oscillations, which accords with Kaftan's results. Moreover the model predicts that when the mitochondria overload with Ca2+, the cytosolic Ca2+ oscillations vanish, which may trigger apoptosis.

  5. Calcium and Vitamin D: Important at Every Age

    Science.gov (United States)

    ... supported by your browser. Home Bone Basics Nutrition Calcium and Vitamin D: Important at Every Age Publication ... Osteoporosis Program For Your Information The Role of Calcium Calcium is needed for our heart, muscles, and ...

  6. Calcium homeostasis and cone signaling are regulated by interactions between calcium stores and plasma membrane ion channels.

    Directory of Open Access Journals (Sweden)

    Tamas Szikra

    Full Text Available Calcium is a messenger ion that controls all aspects of cone photoreceptor function, including synaptic release. The dynamic range of the cone output extends beyond the activation threshold for voltage-operated calcium entry, suggesting another calcium influx mechanism operates in cones hyperpolarized by light. We have used optical imaging and whole-cell voltage clamp to measure the contribution of store-operated Ca(2+ entry (SOCE to Ca(2+ homeostasis and its role in regulation of neurotransmission at cone synapses. Mn(2+ quenching of Fura-2 revealed sustained divalent cation entry in hyperpolarized cones. Ca(2+ influx into cone inner segments was potentiated by hyperpolarization, facilitated by depletion of intracellular Ca(2+ stores, unaffected by pharmacological manipulation of voltage-operated or cyclic nucleotide-gated Ca(2+ channels and suppressed by lanthanides, 2-APB, MRS 1845 and SKF 96365. However, cation influx through store-operated channels crossed the threshold for activation of voltage-operated Ca(2+ entry in a subset of cones, indicating that the operating range of inner segment signals is set by interactions between store- and voltage-operated Ca(2+ channels. Exposure to MRS 1845 resulted in approximately 40% reduction of light-evoked postsynaptic currents in photopic horizontal cells without affecting the light responses or voltage-operated Ca(2+ currents in simultaneously recorded cones. The spatial pattern of store-operated calcium entry in cones matched immunolocalization of the store-operated sensor STIM1. These findings show that store-operated channels regulate spatial and temporal properties of Ca(2+ homeostasis in vertebrate cones and demonstrate their role in generation of sustained excitatory signals across the first retinal synapse.

  7. Bone Up on the Need for Calcium.

    Science.gov (United States)

    Mann, Peggy

    1987-01-01

    Most grade-schoolers drink milk at each meal, but teens, especially girls, often switch to carbonated soda at mealtime just as they should be building up their bone bank of calcium. Why calcium is important and how to get enough of it are covered. (MT)

  8. Stochastic models of intracellular calcium signals

    International Nuclear Information System (INIS)

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed

  9. Stochastic Kinetics of Intracellular Calcium Oscillations

    Institute of Scientific and Technical Information of China (English)

    陈昌胜; 曾仁端

    2003-01-01

    A stochastic model of intracellular calcium oscillations is put forward by taking into account the random opening-closing of Ca2+ channels in endoplasmic reticulum (ER) membrane. The numerical results of the stochastic model show simple and complex calcium oscillations, which accord with the experiment results.

  10. CALCIUM AND THE PREVENTION OF COLON CANCER

    NARCIS (Netherlands)

    WELBERG, JWM; KLEIBEUKER, JH; VANDERMEER, R; MULDER, NH; DEVRIES, EGE

    1991-01-01

    Diet is a major determinant of colon cancer risk. Calcium may protect against colon cancer, presumably by binding cytotoxic bile acids and fatty acids. Numerous studies support this proposition. In subjects at risk for colon cancer oral calcium supplementation has been shown to reduce rectal epithel

  11. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  12. Stochastic models of intracellular calcium signals

    Energy Technology Data Exchange (ETDEWEB)

    Rüdiger, Sten, E-mail: sten.ruediger@physik.hu-berlin.de

    2014-01-10

    Cellular signaling operates in a noisy environment shaped by low molecular concentrations and cellular heterogeneity. For calcium release through intracellular channels–one of the most important cellular signaling mechanisms–feedback by liberated calcium endows fluctuations with critical functions in signal generation and formation. In this review it is first described, under which general conditions the environment makes stochasticity relevant, and which conditions allow approximating or deterministic equations. This analysis provides a framework, in which one can deduce an efficient hybrid description combining stochastic and deterministic evolution laws. Within the hybrid approach, Markov chains model gating of channels, while the concentrations of calcium and calcium binding molecules (buffers) are described by reaction–diffusion equations. The article further focuses on the spatial representation of subcellular calcium domains related to intracellular calcium channels. It presents analysis for single channels and clusters of channels and reviews the effects of buffers on the calcium release. For clustered channels, we discuss the application and validity of coarse-graining as well as approaches based on continuous gating variables (Fokker–Planck and chemical Langevin equations). Comparison with recent experiments substantiates the stochastic and spatial approach, identifies minimal requirements for a realistic modeling, and facilitates an understanding of collective channel behavior. At the end of the review, implications of stochastic and local modeling for the generation and properties of cell-wide release and the integration of calcium dynamics into cellular signaling models are discussed.

  13. Calcium, snails, and birds: a case study

    Directory of Open Access Journals (Sweden)

    R. Mänd

    2000-10-01

    Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

  14. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This...

  15. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    International Nuclear Information System (INIS)

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

  16. Effect of different retarders on the hydration of calcium sulfoaluminate eco-cement pastes

    OpenAIRE

    García-Maté, Marta; De la Torre, Ángeles G.; Aranda, Miguel A. G.; Santacruz, Isabel

    2014-01-01

    The manufacture of Calcium SulfoAluminate (CSA) cements is more environmentally friendly than that of OPC [1] as their production releases up to 40% less CO2 than the latter. The main performances of CSA cements are fast setting time, good-chemical resistance properties and high early strengths. CSA cements are prepared by mixing CSA clinker with different amounts of a calcium sulfate set regulator such as gypsum (CaSO4•2H2O), bassanite (CaSO4•½H2O), or anhydrite (CaSO4), or mixtures of th...

  17. Calcium-sensing receptor: a key target for extracellular calcium signaling in neurons

    Directory of Open Access Journals (Sweden)

    Brian L Jones

    2016-03-01

    Full Text Available Though both clinicians and scientists have long recognized the influence of extracellular calcium on the function of muscle and nervous tissue, recent insights reveal that the mechanisms allowing changes in extracellular calcium to alter cellular excitability have been incompletely understood. For many years the effects of calcium on neuronal signaling were explained only in terms of calcium entry through voltage-gated calcium channels and biophysical charge screening. More recently however, it has been recognized that the calcium-sensing receptor is prevalent in the nervous system and regulates synaptic transmission and neuronal activity via multiple signaling pathways. Here we review the multiplicity of mechanisms by which changes in extracellular calcium alter neuronal signaling and propose that multiple mechanisms are required to describe the full range of experimental observations.

  18. Optogenetic Control of Calcium Oscillation Waveform Defines NFAT as an Integrator of Calcium Load.

    Science.gov (United States)

    Hannanta-Anan, Pimkhuan; Chow, Brian Y

    2016-04-27

    It is known that the calcium-dependent transcription factor NFAT initiates transcription in response to pulsatile loads of calcium signal. However, the relative contributions of calcium oscillation frequency, amplitude, and duty cycle to transcriptional activity remain unclear. Here, we engineer HeLa cells to permit optogenetic control of intracellular calcium concentration using programmable LED arrays. This approach allows us to generate calcium oscillations of constant peak amplitude, in which frequency is varied while holding duty cycle constant, or vice versa. Using this setup and mathematical modeling, we show that NFAT transcriptional activity depends more on duty cycle, defined as the proportion of the integrated calcium concentration over the oscillation period, than on frequency alone. This demonstrates that NFAT acts primarily as a signal integrator of cumulative load rather than a frequency-selective decoder. This approach resolves a fundamental question in calcium encoding and demonstrates the value of optogenetics for isolating individual dynamical components of larger signaling behaviors. PMID:27135540

  19. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani

    2013-01-01

    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  20. Effects of Nickel on Calcium Phosphate Formation

    Science.gov (United States)

    Guerra-López, J.; González, R.; Gómez, A.; Pomés, R.; Punte, G.; Della Védova, C. O.

    2000-05-01

    We have investigated the effect of nickel on calcium phosphate formation from aqueous solutions. The calcium phosphates prepared under different reaction conditions (pH, temperature, and nickel concentration) were characterized by X-ray diffraction, FTIR spectroscopy, and chemical analysis. The apatite compounds were also studied thermogravimetrically. From the combined results of the techniques employed we have determined that nickel favors the formation of brushite and amorphous calcium phosphate. We have found, as well, that the presence of nickel in the solution inhibits calcium hydroxyapatite (CaHAP) and octacalcium phosphate formation. However in the synthesis performed at basic pH and 95°C the apatitic phase (HAP) could be obtained. The present results suggest that the presence of nickel may modify the precipitation of oral calcium phosphate.

  1. Calcium Forms,Subcelluar Distribution and Ultrastructure of Pulp Cells as Influenced by Calcium Deficiency in Apple (Malus pumila) Fruits

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

    Calcium in Red Fuji and Starkrimson apples during storage were fractionated by sequent extracting. Localization and distribution of calcium and influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improved method of potassium pyroantimonate technique. Results indicated that spraying calcium solution on surface of young fruits increased contents of calcium in all forms. During storage, contents of soluble calcium and pectic calcium declined and thosein calcium phosphate, calcium oxalate and calcium silicate increased. Calcium contents of Red Fuji in all forms were higher than those of Starkrimson, indicating that calcium accumulating capability of Red Fuji fruits preceded that of Starkrimson. Under transmission electron microscopy, calcium antimonite precipitates (CaAP) was mainly distributed in cell wall, tonoplast, nuclear membrane and nucleoplasm,much more CaAP deposited in vacuole. Calcium deficiency during storage leads to decrease of CaAP in locations mentioned above, disappearance of compartmentation, and entrance of CaAP to cytoplasm. Transformation from soluble calcium and pectic calcium to calcium phosphate,oxalate and damages of biomembranes structuraly and functionally resulted from calcium deficiency during storage were the crucial causation of physiological disorder.

  2. Expert review on coronary calcium

    Directory of Open Access Journals (Sweden)

    Matthew J Budoff

    2008-04-01

    Full Text Available Matthew J Budoff, Khawar M GulDivision of Cardiology, Saint John’s Cardiovascular Research Center, Los Angeles Biomedical Research Institute at Harbor-UCLA, Torrance, California, USAAbstract: While there is no doubt that high risk patients (those with >20% ten year risk of future cardiovascular event need more aggressive preventive therapy, a majority of cardiovascular events occur in individuals at intermediate risk (10%–20% ten year risk. Accurate risk assessment may be helpful in decreasing cardiovascular events through more appropriate targeting of preventive measures. It has been suggested that traditional risk assessment may be refined with the selective use of coronary artery calcium (CAC or other methods of subclinical atherosclerosis measurement. Coronary calcification is a marker of atherosclerosis that can be quantified with the use of cardiac CT and it is proportional to the extent and severity of atherosclerotic disease. The published studies demonstrate a high sensitivity of CAC for the presence of coronary artery disease but a lower specificity for obstructive CAD depending on the magnitude of the CAC. Several large clinical trials found clear, incremental predictive value of CAC over the Framingham risk score when used in asymptomatic patients. Based on multiple observational studies, patients with increased plaque burdens (increased CAC are approximately ten times more likely to suffer a cardiac event over the next 3–5 years. Coronary calcium scores have outperformed conventional risk factors, highly sensitive C-reactive protein (CRP and carotid intima media thickness (IMT as a predictor of cardiovascular events. The relevant prognostic information obtained may be useful to initiate or intensify appropriate treatment strategies to slow the progression of atherosclerotic vascular disease. Current data suggests intermediate risk patients may benefit most from further risk stratification with cardiac CT, as CAC testing is

  3. Diagnosis and assessment of skeletal related disease using calcium 41

    Science.gov (United States)

    Hillegonds, Darren J.; Vogel, John S.; Fitzgerald, Robert L.; Deftos, Leonard J.; Herold, David; Burton, Douglas W.

    2012-05-15

    A method of determining calcium metabolism in a patient comprises the steps of administering radioactive calcium isotope .sup.41Ca to the patient, allowing a period of time to elapse sufficient for dissemination and reaction of the radioactive calcium isotope .sup.41Ca by the patient, obtaining a sample of the radioactive calcium isotope .sup.41Ca from the patient, isolating the calcium content of the sample in a form suitable for precise measurement of isotopic calcium concentrations, and measuring the calcium content to determine parameters of calcium metabolism in the patient.

  4. Calcium-imaging with Fura-2 in isolated cerebral microvessels

    DEFF Research Database (Denmark)

    Hess, Jörg; Jensen, Claus V.; Diemer, Nils Henrik

    1991-01-01

    Neuropathology, cytoplasmic free calcium, Fura-2 fluorescence, image analysis, blood-brain barrier......Neuropathology, cytoplasmic free calcium, Fura-2 fluorescence, image analysis, blood-brain barrier...

  5. Calcium: a code coupling tool

    International Nuclear Information System (INIS)

    Today, the calculation performances of computers allow the precise and global simulation of complex industrial processes such as the functioning of a nuclear reactor core. One can question the need for the elaboration of new global numerical models in order to make use of the overall capability of computers. Another less time consuming solution consist in the coupling of existing well validated numerical models in order to make them working together. This paper presents the basic principles of the coupling of numerical codes, the tools required, the Calcium tool for codes coupling and an example of application of this tool in the coupling of the THYC (EdF), COCCINELLE (EdF) and CATHARE (CEA-EdF-Framatome) codes for the modeling of the thermal-hydraulic and neutronic behaviour of a reactor core during accidental situation. (J.S.)

  6. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

    Henriksen, Maiken L; Lindhardt Madsen, Kirstine; Skjoedt, Karsten;

    2014-01-01

    Immunoaffinity chromatography is a powerful fractionation technique that has become indispensable for protein purification and characterization. However, it is difficult to retrieve bound proteins without using harsh or denaturing elution conditions, and the purification of scarce antigens...... to homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m...... chromatography was superior to the traditional immunoaffinity chromatographies and resulted in a nine-fold improvement of the purification factor. The technique is applicable for the purification of proteins in complex mixtures by single-step fractionation without the denaturation of eluted antigens...

  7. A calcium isotope test of end-Permian ocean acidification using biogenic apatite

    Science.gov (United States)

    Hinojosa, J.; Brown, S. T.; DePaolo, D. J.; Paytan, A.; Shen, S.; Chen, J.; Payne, J.

    2011-12-01

    Submarine erosional truncation of uppermost Permian carbonate strata has been interpreted to reflect ocean acidification coincident with the end-Permian mass extinction. Although this scenario is consistent with carbon isotope and paleontological data, several alternative scenarios, such as ocean overturn or collapse of the biological pump, can also account for the carbon isotope and paleontological evidence. Calcium isotopes provide a geochemical proxy to test between acidification and alternative scenarios. Specifically, a negative shift in the calcium isotope composition (δ44/40Ca) of seawater is predicted under the acidification scenario but not the alternatives. The δ44/40Ca of carbonate rocks from south China exhibits a negative excursion of approximately 0.3%, but this shift could result from either a change in the δ44/40Ca of seawater or a change in carbonate mineralogy because calcite and aragonite exhibit substantially different fractionation factors relative to seawater. To test whether the negative shift in δ44/40Ca reflects seawater δ44/40Ca or carbonate mineralogy, we measured the δ44/40Ca of conodont microfossils (calcium hydroxyapatite) from the global stratotype section for the Permian-Triassic boundary at Meishan, China. The conodont δ44/40Ca record shows a negative excursion similar in stratigraphic position and magnitude to that previously observed in carbonate rocks. Parallel negative excursions in the δ44/40Ca of carbonate rocks and conodont microfossils cannot be accounted for by a change in carbonate mineralogy but are consistent with a negative shift in the δ44/40Ca of seawater. These data add further support for the ocean acidification scenario, pointing toward strong similarities between the greatest catastrophe in the history of animal life and anticipated global change during the 21st century.

  8. Fast kinetics of calcium signaling and sensor design.

    Science.gov (United States)

    Tang, Shen; Reddish, Florence; Zhuo, You; Yang, Jenny J

    2015-08-01

    Fast calcium signaling is regulated by numerous calcium channels exhibiting high spatiotemporal profiles which are currently measured by fluorescent calcium sensors. There is still a strong need to improve the kinetics of genetically encoded calcium indicators (sensors) to capture calcium dynamics in the millisecond time frame. In this review, we summarize several major fast calcium signaling pathways and discuss the recent developments and application of genetically encoded calcium indicators to detect these pathways. A new class of genetically encoded calcium indicators designed with site-directed mutagenesis on the surface of beta-barrel fluorescent proteins to form a pentagonal bipyramidal-like calcium binding domain dramatically accelerates calcium binding kinetics. Furthermore, novel genetically encoded calcium indicators with significantly increased fluorescent lifetime change are advantageous in deep-field imaging with high light-scattering and notable morphology change.

  9. Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets.

    Science.gov (United States)

    Thacher, Tom D; Abrams, Steven A

    2010-11-01

    Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH)D concentrations, and serum 1,25(OH)(2) D values are markedly elevated. Studies of Nigerian children with rickets demonstrated they have high fractional calcium absorption. A high-phytate diet was demonstrated to increase calcium absorption compared with the fasting state, and enzymatic dephytinization did not significantly improve calcium absorption. When given vitamin D, children with rickets have a marked increase in 1,25(OH)(2) D concentrations without any change in fractional calcium absorption. No positive relationship was found between fractional calcium absorption and serum 25(OH)D concentrations in children on low-calcium diets. More research is needed to understand the interaction between calcium and vitamin D and the role of vitamin D in calcium absorption.

  10. Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.

    2002-01-01

    Full Text Available Dietary calcium lowers the risk of nephrolithiasis due to a decreased absorption of dietary oxalate that is bound by intestinal calcium. The aim of the present study was to evaluate oxaluria in normocalciuric and hypercalciuric lithiasic patients under different calcium intake. Fifty patients (26 females and 24 males, 41 ± 10 years old, whose 4-day dietary records revealed a regular low calcium intake (<=500 mg/day, received an oral calcium load (1 g/day for 7 days. A 24-h urine was obtained before and after load and according to the calciuria under both diets, patients were considered as normocalciuric (NC, N = 15, diet-dependent hypercalciuric (DDHC, N = 9 or diet-independent hypercalciuric (DIHC, N = 26. On regular diet, mean oxaluria was 30 ± 14 mg/24 h for all patients. The 7-day calcium load induced a significant decrease in mean oxaluria compared to the regular diet in NC and DIHC (20 ± 12 vs 26 ± 7 and 27 ± 18 vs 32 ± 15 mg/24 h, respectively, P<0.05 but not in DDHC patients (22 ± 10 vs 23 ± 5 mg/24 h. The lack of an oxalate decrease among DDHC patients after the calcium load might have been due to higher calcium absorption under higher calcium supply, with a consequent lower amount of calcium left in the intestine to bind with oxalate. These data suggest that a long-lasting regular calcium consumption <500 mg was not associated with high oxaluria and that a subpopulation of hypercalciuric patients who presented a higher intestinal calcium absorption (DDHC tended to hyperabsorb oxalate as well, so that oxaluria did not change under different calcium intake.

  11. The influence of calcium on technological properties and micropurity of steel castings

    Directory of Open Access Journals (Sweden)

    J. Hampl

    2016-07-01

    Full Text Available The paper analyzes the technological parameters, micro-purity and mechanical properties of castings of steel alloyed with calcium. The effect of calcium on the steel was analyzed on samples taken in the process of casting heavy castings and ingots of the weight of ranging from 40 000 to 60 000 kg. Samples for the determination of the liquidus temperature and the solidus temperature of cast steels were analysed using differential thermal analysis (DTA. The production of low alloyed steel grades was performed on the EAF - ASEA-SKF facilities and the production of highalloyed steels on the EAF - ASEA-SKF - SS-VOD facilities. The purity calcium was added into the steel by the injection of a stuffed profile.

  12. Simultaneous spectrophotometric determination of atorvastatin calcium and amlodipine besylate in tablets

    Directory of Open Access Journals (Sweden)

    Khan M

    2006-01-01

    Full Text Available Two simple, accurate and precise methods for simultaneous estimation of atorvastatin calcium and amlodipine besylate in combined dosage form have been described. First method employs formation and solving of simultaneous equations using 245 nm and 363 nm as two analytical wavelengths. Second is dual wavelength method, which uses the difference of absorbance value at 259.9 nm and 354 nm for estimation of atorvastatin calcium and absorbance at 363 nm for amlodipine besylate. Fifty percent methanol was used as solvent, in which atorvastatin calcium and amlodipine besylate shows linearity in the range of 0-40 µg/ml and 0-20 µg/ml, respectively. Standard deviation was < 1.5 in the assay of tablets. Methods were validated as per ICH norms and accuracy, precision, repeatability and robustness was found to be with in the acceptable limit.

  13. Calcium signaling in physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    He-ping CHENG; Sheng WEI; Li-ping WEI; Alexei VERKHRATSKY

    2006-01-01

    Calcium ions are the most ubiquitous and pluripotent cellular signaling molecules that control a wide variety of cellular processes.The calcium signaling system is represented by a relatively limited number of highly conserved transporters and channels,which execute Ca2+ movements across biological membranes and by many thousands of Ca2+-sensitive effectors.Molecular cascades,responsible for the generation of calcium signals,are tightly controlled by Ca2+ ions themselves and by genetic factors,which tune the expression of different Ca2+-handling molecules according to adaptational requirements.Ca2+ ions determine normal physiological reactions and the development of many pathological processes.

  14. Calcium Signaling Is Required for Erythroid Enucleation.

    Science.gov (United States)

    Wölwer, Christina B; Pase, Luke B; Russell, Sarah M; Humbert, Patrick O

    2016-01-01

    Although erythroid enucleation, the property of erythroblasts to expel their nucleus, has been known for 7ore than a century, surprisingly little is known regarding the molecular mechanisms governing this unique developmental process. Here we show that similar to cytokinesis, nuclear extrusion requires intracellular calcium signaling and signal transduction through the calmodulin (CaM) pathway. However, in contrast to cytokinesis we found that orthochromatic erythroblasts require uptake of extracellular calcium to enucleate. Together these functional studies highlight a critical role for calcium signaling in the regulation of erythroid enucleation.

  15. Calcium Signaling Is Required for Erythroid Enucleation.

    Directory of Open Access Journals (Sweden)

    Christina B Wölwer

    Full Text Available Although erythroid enucleation, the property of erythroblasts to expel their nucleus, has been known for 7ore than a century, surprisingly little is known regarding the molecular mechanisms governing this unique developmental process. Here we show that similar to cytokinesis, nuclear extrusion requires intracellular calcium signaling and signal transduction through the calmodulin (CaM pathway. However, in contrast to cytokinesis we found that orthochromatic erythroblasts require uptake of extracellular calcium to enucleate. Together these functional studies highlight a critical role for calcium signaling in the regulation of erythroid enucleation.

  16. Calcium Signaling Is Required for Erythroid Enucleation

    Science.gov (United States)

    Russell, Sarah M.; Humbert, Patrick O.

    2016-01-01

    Although erythroid enucleation, the property of erythroblasts to expel their nucleus, has been known for 7ore than a century, surprisingly little is known regarding the molecular mechanisms governing this unique developmental process. Here we show that similar to cytokinesis, nuclear extrusion requires intracellular calcium signaling and signal transduction through the calmodulin (CaM) pathway. However, in contrast to cytokinesis we found that orthochromatic erythroblasts require uptake of extracellular calcium to enucleate. Together these functional studies highlight a critical role for calcium signaling in the regulation of erythroid enucleation. PMID:26731108

  17. Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

    2015-06-01

    Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

  18. Thermochemistry of calcium oxide and calcium hydroxide in fluoride slags

    Science.gov (United States)

    Chattopadhyay, S.; Mitchell, A.

    1990-08-01

    Calcium oxide activity in binary CaF2-CaO and ternary CaF2-CaO-Al2O3 and CaF2-CaO-SiO2 slags has been determined by CO2-slag equilibrium experiments at 1400 °C. The carbonate ca-pacity of these slags has also been computed and compared with sulfide capacity data available in the literature. The similarity in trends suggests the possibility of characterizing carbonate capacity as an alternative basicity index for fluoride-base slags. Slag-D2O equilibrium experi-ments are performed at 1400°C with different fluoride-base slags to determine water solubility at two different partial pressures of D2O, employing a new slag sampling technique. A novel isotope tracer detection technique is employed to analyze water in the slags. The water solubility data found show higher values than the previous literature data by an order of magnitude but show a linear relationship with the square root of water vapor partial pressure. The activity of hydroxide computed from the data is shown to be helpful in estimating water solubility in in-dustrial electroslag remelting (ESR) slags.

  19. Modulation of Intracellular Calcium Levels by Calcium Lactate Affects Colon Cancer Cell Motility through Calcium-Dependent Calpain

    OpenAIRE

    Pasupathi Sundaramoorthy; Jae Jun Sim; Yeong-Su Jang; Siddhartha Kumar Mishra; Keun-Yeong Jeong; Poonam Mander; Oh Byung Chul; Won-Sik Shim; Seung Hyun Oh; Ky-Youb Nam; Hwan Mook Kim

    2015-01-01

    Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa), its downstrea...

  20. Tx1, from Phoneutria nigriventer spider venom, interacts with dihydropyridine sensitive-calcium channels in GH3 cells

    International Nuclear Information System (INIS)

    The aim of this work was to use the binding assay of tritiated-dihydropyridine and radioiodinated Tx1, isolated from the Phoneutria nigriventer venom, in order to show the presence of Cav1 calcium channels on pituitary tumour cell (GH3). We showed that GH3 cells have specific sites for 125I-Tx1, which are sensitive to nifedipine (∼20%). Reverse competition assay with 3H-PN200-110 (40% inhibition) and electrophysiological data (50% inhibition) suggest that Cav1 calcium channels are target sites for this toxin. To summarize, Tx1 binds to specific sites on GH3 cells and this interaction results in Cav1 calcium channel blockade. 3H-PN200-110 and 125I-Tx1 binding assays proved to be useful tools to show the presence of calcium channels on GH3 cells. (author)

  1. Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium

    Energy Technology Data Exchange (ETDEWEB)

    Wernimont, Amy K; Artz, Jennifer D.; Jr, Patrick Finerty; Lin, Yu-Hui; Amani, Mehrnaz; Allali-Hassani, Abdellah; Senisterra, Guillermo; Vedadi, Masoud; Tempel, Wolfram; Mackenzie, Farrell; Chau, Irene; Lourido, Sebastian; Sibley, L. David; Hui, Raymond (Toronto); (WU-MED)

    2010-09-21

    Calcium-dependent protein kinases (CDPKs) have pivotal roles in the calcium-signaling pathway in plants, ciliates and apicomplexan parasites and comprise a calmodulin-dependent kinase (CaMK)-like kinase domain regulated by a calcium-binding domain in the C terminus. To understand this intramolecular mechanism of activation, we solved the structures of the autoinhibited (apo) and activated (calcium-bound) conformations of CDPKs from the apicomplexan parasites Toxoplasma gondii and Cryptosporidium parvum. In the apo form, the C-terminal CDPK activation domain (CAD) resembles a calmodulin protein with an unexpected long helix in the N terminus that inhibits the kinase domain in the same manner as CaMKII. Calcium binding triggers the reorganization of the CAD into a highly intricate fold, leading to its relocation around the base of the kinase domain to a site remote from the substrate binding site. This large conformational change constitutes a distinct mechanism in calcium signal-transduction pathways.

  2. Effect of calcium chloride addition on ice cream structure and quality.

    Science.gov (United States)

    Costa, F F; Resende, J V; Abreu, L R; Goff, H D

    2008-06-01

    The influence of calcium fortification by the addition of calcium chloride on quality parameters of ice cream based on physical properties was investigated, as was the effect of kappa-carrageenan at modifying the effects of this calcium fortification. Four ice cream mixes of conventional composition, with added kappa-carrageenan (0 or 0.025%) and added calcium chloride (0 or 4.4 g L(-1) = 40 mM of added Ca(2+)), were prepared. Modulated temperature-differential scanning calorimetry was used to investigate the effect of calcium chloride on the nucleation temperature, enthalpy of melting, and freezing point depression. The protein composition of 15.4% (wt/wt) reconstituted skim milk powder solutions with or without 4.4 g L(-1) added CaCl(2) and in the supernatant after ultracentrifugation was determined. Fat particle size distributions in ice cream were characterized by light scattering. Ice crystal sizes before and after temperature cycling were determined by cold-stage light microscopy. The results demonstrated that the addition of calcium chloride led to a substantial increase in ice crystal sizes and in fat partial coalescence, which were exacerbated by the addition of kappa-carrageenan. These results can be explained by the interaction between Ca(2+) ions and casein micelles, rather than any effects on freezing point depression. The calcium ions led to a more compact micelle, less serum beta-casein, and high fat destabilization, all of which would be expected to reduce macromolecular structure and volume occupancy in the unfrozen phase, which led to increased rates of ice recrystallization. PMID:18487638

  3. Inactivation kinetics and pharmacology distinguish two calcium currents in mouse pancreatic B-cells

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, W.F.; Satin, L.S.; Cook, D.L. (Univ. of Washington School of Medicine, Seattle (USA))

    1991-02-01

    Voltage-dependent calcium currents were studied in cultured adult mouse pancreatic B-cells using the whole-cell voltage-clamp technique. When calcium currents were elicited with 10-sec depolarizing command pulses, the time course of inactivation was well fit by the sum of two exponentials. The more rapidly-inactivating component had a time constant of 75 +/- 5 msec at 0 mV and displayed both calcium influx- and voltage-dependent inactivation, while the more slowly-inactivating component had a time constant of 2750 +/- 280 msec at 0 mV and inactivated primarily via voltage. The fast component was subject to greater steady-state inactivation at holding potentials between -100 and -40 mV and activated at a lower voltage threshold. This component was also significantly reduced by nimodipine (0.5 microM) when a holding potential of -100 mV was used, whereas the slow component was unaffected. In contrast, the slow component was greatly increased by replacing external calcium with barium, while the fast component was unchanged. Cadmium (1-10 microM) displayed a voltage-dependent block of calcium currents consistent with a greater effect on the high-threshold, more-slowly inactivating component. Taken together, the data suggest that cultured mouse B-cells, as with other insulin-secreting cells we have studied, possess at least two distinct calcium currents. The physiological significance of two calcium currents having distinct kinetic and steady-state inactivation characteristics for B-cell burst firing and insulin secretion is discussed.

  4. In vivo Calcium Imaging of Evoked Calcium Waves in the Embryonic Cortex

    OpenAIRE

    Yuryev, Mikhail; Pellegrino, Christophe; Jokinen, Ville; Andriichuk, Liliia; Khirug, Stanislav; Khiroug, Leonard; Rivera, Claudio

    2016-01-01

    The dynamics of intracellular calcium fluxes are instrumental in the proliferation, differentiation, and migration of neuronal cells. Knowledge thus far of the relationship between these calcium changes and physiological processes in the developing brain has derived principally from ex vivo and in vitro experiments. Here, we present a new method to image intracellular calcium flux in the cerebral cortex of live rodent embryos, whilst attached to the dam through the umbilical cord. Using this ...

  5. Technology obtaining of nitrogen fertilizer from the calcium is containing waste of production of calcium saltpetre

    OpenAIRE

    Власян, Світлана Варужанівна; Шестозуб, Анатолій Борисович; Волошин, Микола Дмитрович

    2013-01-01

    The new technology of obtaining nitrogen fertilizer from calcium-containing sludge of calcium saltpeter production is considered in the paper. The main objective of the research is the development of processing technology of sludge of calcium saltpeter production into alkaline nitrogen fertilizer, analysis of the composition of initial material and finished product, testing of fertilizer by means of vegeta­tive studies and determination of expenditure of drying agent that is exhaust gases of ...

  6. Relationship between sealing ability of Activ GP and Gutta Flow and methods of calcium hydroxide removal

    Directory of Open Access Journals (Sweden)

    Vineeta Nikhil

    2012-01-01

    Full Text Available Aim: To evaluate the effect of method of calcium hydroxide intracanal dressing removal, on sealing ability of Gutta Flow and Activ GP. Materials and Methods: Seventy extracted mandibular premolars were sectioned at CEJ and canals were prepared with profile 4% rotary file till #40. Canals were filled with calcium hydroxide, coronally sealed with Cavit G and stored at 37°C. After 7 days, samples were divided on the basis of calcium hydroxide removal method (Master apical file, Navi Tip FX, and F File and obturating material (Activ GP and Gutta Flow. Three coats of nail polish were applied except 2 mm around apical foramen and samples were immersed in India ink dye, sectioned, and observed under stereomicroscope for microleakage. Results: The results were statistically analyzed with one way ANOVA-F with Tukey HSD test with the null hypothesis set as 5%. Conclusions: The seal of the canal system was adversely impacted by residual calcium hydroxide when Activ GP and Gutta Flow were used as obturating material and the sealing ability of Activ GP and Gutta Flow was better when MAF was used for removal of calcium hydroxide than F file or Navi tip FX.

  7. 21 CFR 172.120 - Calcium disodium EDTA.

    Science.gov (United States)

    2010-04-01

    ... Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA (calcium... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium disodium EDTA. 172.120 Section 172.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  8. Selective extraction of calcium on tri-n-butyl phosphate plasticized selective extraction of calcium on tri-n-butyl phosphate plasticized polyurethane foam for its spectrophotometric determination in glass and ceramics.

    Science.gov (United States)

    Mondal, Jayanta K; Kundu, Dipali

    2005-12-01

    The present paper describes the application of a solid phase extraction system in order to separate traces of calcium from glass and ceramics for its spectrophotometric determination. The method is based on the extraction of calcium from sodium hydroxide solution by tri-n-butyl phosphate (TBP) loaded polyurethane foam (PUF), followed by its elution in hydrochloric acid. The spectrophotometric measurement of the absorbance of calcium complex with calconcarboxylic acid (2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid) takes place at pH 12. The following parameters were studied: effects of sodium hydroxide concentration and temperature on the extraction of calcium, time of equilibration for quantitative calcium extraction, effect of TBP concentration, effect of hydrochloric acid concentration for quantitative elution of calcium from PUF, effect of pH and concentration of calconcarboxylic acid for quantitative formation of the complex with calcium, effect of acetone on the stability of calcium-calconcarboxylic acid complex and influence of diverse ions on calcium sorption by TBP-loaded PUF. The results show that calcium traces can be separated onto TBP-loaded PUF from 0.25 mol L(-1) NaOH at 30 +/- 5 degrees C within 30 min. PUF was loaded with TBP in CCl4 (40% v/v). Elution of calcium was done in 1.0 mol l(-1) HCl. The calcium formed a complex with calconcarboxylic acid at pH 12 and absorbance was measured at 560 nm in acetone-water medium. Molar absorptivity was found to be 1.082 x 10(4) l mol(-1) cm(-1). The method obeys Beer's law from 0.10 to 5.0 microg ml(-1) Ca. The validity of the method was established by its successful application in NIST standard reference materials. The method proposed was applied to determine calcium in glass and ceramic materials. The results of the proposed method are comparable with the results of ICP-AES analysis and they are found to be in good agreement. PMID:16379392

  9. Astrocyte calcium signaling: the third wave.

    Science.gov (United States)

    Bazargani, Narges; Attwell, David

    2016-02-01

    The discovery that transient elevations of calcium concentration occur in astrocytes, and release 'gliotransmitters' which act on neurons and vascular smooth muscle, led to the idea that astrocytes are powerful regulators of neuronal spiking, synaptic plasticity and brain blood flow. These findings were challenged by a second wave of reports that astrocyte calcium transients did not mediate functions attributed to gliotransmitters and were too slow to generate blood flow increases. Remarkably, the tide has now turned again: the most important calcium transients occur in fine astrocyte processes not resolved in earlier studies, and new mechanisms have been discovered by which astrocyte [Ca(2+)]i is raised and exerts its effects. Here we review how this third wave of discoveries has changed our understanding of astrocyte calcium signaling and its consequences for neuronal function.

  10. Discrete stochastic modeling of calcium channel dynamics

    CERN Document Server

    Baer, M E; Levine, H; Tsimring, L S; Baer, Markus; Falcke, Martin; Levine, Herbert; Tsimring, Lev S.

    1999-01-01

    We propose a simple discrete stochastic model for calcium dynamics in living cells. Specifically, the calcium concentration distribution is assumed to give rise to a set of probabilities for the opening/closing of channels which release calcium thereby changing those probabilities. We study this model in one dimension, analytically in the mean-field limit of large number of channels per site N, and numerically for small N. As the number of channels per site is increased, the transition from a non-propagating region of activity to a propagating one changes in nature from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state, in a parameter range where the limiting deterministic model exhibits only single pulse propagation.

  11. Discrete Stochastic Modeling of Calcium Channel Dynamics

    International Nuclear Information System (INIS)

    We propose a discrete stochastic model for calcium dynamics in living cells. A set of probabilities for the opening/closing of calcium channels is assumed to depend on the calcium concentration. We study this model in one dimension, analytically in the limit of a large number of channels per site N , and numerically for small N . As the number of channels per site is increased, the transition from a nonpropagating region of activity to a propagating one changes from one described by directed percolation to that of deterministic depinning in a spatially discrete system. Also, for a small number of channels a propagating calcium wave can leave behind a novel fluctuation-driven state. (c) 2000 The American Physical Society

  12. 21 CFR 184.1195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

    ... with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available from the National Academy Press, 2101... four moles of water per mole of calcium citrate. (b) The ingredient meets the specifications of...

  13. Calcium signaling in neocortical development.

    Science.gov (United States)

    Uhlén, Per; Fritz, Nicolas; Smedler, Erik; Malmersjö, Seth; Kanatani, Shigeaki

    2015-04-01

    The calcium ion (Ca(2+) ) is an essential second messenger that plays a pivotal role in neurogenesis. In the ventricular zone (VZ) of the neocortex, neural stem cells linger to produce progenitor cells and subsequently neurons and glial cells, which together build up the entire adult brain. The radial glial cells, with their characteristic radial fibers that stretch from the inner ventricular wall to the outer cortex, are known to be the neural stem cells of the neocortex. Migrating neurons use these radial fibers to climb from the proliferative VZ in the inner part of the brain to the outer layers of the cortex, where differentiation processes continue. To establish the complex structures that constitute the adult cerebral cortex, proliferation, migration, and differentiation must be tightly controlled by various signaling events, including cytosolic Ca(2+) signaling. During development, cells regularly exhibit spontaneous Ca(2+) activity that stimulates downstream effectors, which can elicit these fundamental cell processes. Spontaneous Ca(2+) activity during early neocortical development depends heavily on gap junctions and voltage dependent Ca(2+) channels, whereas later in development neurotransmitters and synapses exert an influence. Here, we provide an overview of the literature on Ca(2+) signaling and its impact on cell proliferation, migration, and differentiation in the neocortex. We point out important historical studies and review recent progress in determining the role of Ca(2+) signaling in neocortical development.

  14. Effect of albumin and free calcium concentrations on calcium binding in vitro.

    OpenAIRE

    Besarab, A; DeGuzman, A; Swanson, J W

    1981-01-01

    In vivo equilibrium dialysis studies were performed to define further the characteristics of calcium binding to bovine albumin. The concentration range for albumin (1 to 9 g/dl) as well as ultrafilterable calcium (0.5 to 2.5 mM) studied encompassed those that might be ordinarily encountered in most clinical situations. Major differences in the regressions of total calcium on ultrafilterable calcium occurred at albumin concentrations of 1, 2, and 9 g/dl but only small differences at albumin co...

  15. Characterization of Calcium Compounds in Opuntia ficus indica as a Source of Calcium for Human Diet

    OpenAIRE

    Isela Rojas-Molina; Elsa Gutiérrez-Cortez; Moustapha Bah; Alejandra Rojas-Molina; César Ibarra-Alvarado; Eric Rivera-Muñoz; Alicia del Real; Ma. de los Angeles Aguilera-Barreiro

    2015-01-01

    Analyses of calcium compounds in cladodes, soluble dietary fiber (SDF), and insoluble dietary fiber (IDF) of Opuntia ficus indica are reported. The characterization of calcium compounds was performed by using Scanning Electron Microscopy, Energy Dispersive Spectrometry, X-ray diffraction, and infrared spectroscopy. Atomic Absorption Spectroscopy and titrimetric methods were used for quantification of total calcium and calcium compounds. Whewellite (CaC2O4·H2O), weddellite (CaC2O4·(H2O)2.375),...

  16. Relating a calcium indicator signal to the unperturbed calcium concentration time-course

    Directory of Open Access Journals (Sweden)

    Abarbanel Henry DI

    2007-02-01

    Full Text Available Abstract Background Optical indicators of cytosolic calcium levels have become important experimental tools in systems and cellular neuroscience. Indicators are known to interfere with intracellular calcium levels by acting as additional buffers, and this may strongly alter the time-course of various dynamical variables to be measured. Results By investigating the underlying reaction kinetics, we show that in some ranges of kinetic parameters one can explicitly link the time dependent indicator signal to the time-course of the calcium influx, and thus, to the unperturbed calcium level had there been no indicator in the cell.

  17. Diagnosis and clinical manifestations of calcium pyrophosphate and basic calcium phosphate crystal deposition diseases.

    Science.gov (United States)

    Ea, Hang-Korng; Lioté, Frédéric

    2014-05-01

    Basic calcium phosphate and pyrophosphate calcium crystals are the 2 main calcium-containing crystals that can deposit in all skeletal tissues. These calcium crystals give rise to numerous manifestations, including acute inflammatory attacks that can mimic alarming and threatening differential diagnoses, osteoarthritis-like lesions, destructive arthropathies, and calcific tendinitis. Awareness of uncommon localizations and manifestations such as intraspinal deposition (eg, crowned dens syndrome, tendinitis of longus colli muscle, massive cervical myelopathy compression) prevents inappropriate procedures and cares. Coupling plain radiography, ultrasonography, computed tomography, and synovial fluid analysis allow accurate diagnosis by directly or indirectly identifying the GRAAL of microcrystal-related symptoms.

  18. Effect of Calcium on the Vanadium Extraction from High Calcium Type Stone Coal

    Institute of Scientific and Technical Information of China (English)

    BAO Shenxu; LIANG Liang; ZHANG Yimin; HAN Shihua; HU Yangjia

    2015-01-01

    The high calcium type stone coal from Hubei province was leached by water and dilute acid separately after being roasted with different dosage of NaCl. The water leaching rate of vanadium (WLRV) was low and only 26.8%of vanadium can be leached by water when 4%NaCl was added, but the acid leaching rate of vanadium (ALRV) was relatively high. Calcium in the high calcium type stone coal is greatly superfluous relative to vanadium, hence, the calcium reacts with vanadium to form Ca(VO3)2, Ca2V2O7 and Ca3(VO4)2 orderly during the stone coal roasting process and high temperature is beneficial to the reactions between calcium and vanadium, which was validated by simulated reactions between pure calcium carbonate and vanadium pentoxide. These calcium vanadates are all water insoluble but acid soluble and this causes the low WLRV and relatively high ALRV. After calcium removal by HCl, the WLRV is highly enhanced and reaches about 50%when only 2%NaCl was added. If the HCl content is too high, the stone coal is easily sintered and the formed glass structure can enwrap vanadium, which leads the WLRV to decline. Single water leaching process is not appropriate to extract vanadium from high calcium type stone coal.

  19. Study of calcium chloride and calcium nitrate purification on inorganic sorbents

    International Nuclear Information System (INIS)

    Purification of calcium chloride and calcium nitrate from iron, chromium, manganese and cobalt impurities by sorption on some inorganic collectors are considered in this article. Study was conducted by means of radioactive-tracer technique at concurrent use of several γ-radioactive isotopes. As a collectors were used hydrated aluminium and zirconium oxides. Dependence of effectiveness of precipitation by collectors on ph-value of medium, quantity of collector, nature and concentration of components is studied. Optimal parameters of purification of calcium chloride and calcium nitrate are defined.

  20. ERp57 modulates mitochondrial calcium uptake through the MCU.

    Science.gov (United States)

    He, Jingquan; Shi, Weikang; Guo, Yu; Chai, Zhen

    2014-06-01

    ERp57 participates in the regulation of calcium homeostasis. Although ERp57 modulates calcium flux across the plasma membrane and the endoplasmic reticulum membrane, its functions on mitochondria are largely unknown. Here, we found that ERp57 can regulate the expression of the mitochondrial calcium uniporter (MCU) and modulate mitochondrial calcium uptake. In ERp57-silenced HeLa cells, MCU was downregulated, and the mitochondrial calcium uptake was inhibited, consistent with the effect of MCU knockdown. When MCU was re-expressed in the ERp57 knockdown cells, mitochondrial calcium uptake was restored. Thus, ERp57 is a potent regulator of mitochondrial calcium homeostasis.

  1. Understanding calcium dynamics experiments and theory

    CERN Document Server

    Malchow, Dieter

    2003-01-01

    Intracellular Calcium is an important messenger in living cells. Calcium dynamics display complex temporal and spatial structures created by the concentration patterns which are characteristic for a nonlinear system operating far from thermodynamic equilibrium. Written as a set of tutorial reviews on both experimental facts and theoretical modelling, this volume is intended as an introduction and modern reference in the field for graduate students and researchers in biophysics, biochemistry and applied mathematics.

  2. DETERMINATION OF CALCIUM CONTENT IN DIETARY SUPPLEMENTS

    OpenAIRE

    Marjanović-Balaban, Željka R.; Antunović, Vesna R.; Jelić, Dijana R.; Živković, Tanja M.

    2015-01-01

    Calcium is a macro element that is very important for the human body: its content and circulation in the body is large, it serves as the electrolyte, it has a building role and participates in the process of metabolism. The European Union, the World Health Organization (WHO) and the Ministry of Food and Drug (Food and Drug Administration, FDA) gave the RDA (Recommended Dietary Allowances,) for this macro element. The absorption and bioavailability of the calcium may vary depending on a number...

  3. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula. PMID:15236477

  4. Gel time of calcium acrylate grouting material

    Institute of Scientific and Technical Information of China (English)

    韩同春

    2004-01-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerization reaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reaction kinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time of calcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and an example is provided to verify the proposed formula.

  5. Rickets induced by calcium or phosphate depletion.

    OpenAIRE

    Abugassa, S.; Svensson, O.

    1990-01-01

    We studied the effects of calciopenia and phosphopenia on longitudinal growth, skeletal mineralization, and development of rickets in young Sprague-Dawley rats. At an age of 21 days, two experimental groups were given diets containing 0.02% calcium or 0.02% phosphorus; otherwise the diets were nutritionally adequate. After 7, 14, and 21 days, five animals from each group were randomly chosen. The animals were anaesthetized and blood samples were drawn for analysis of calcium, phosphorus, and ...

  6. A calcium-induced calcium release mechanism mediated by calsequestrin.

    Science.gov (United States)

    Lee, Young-Seon; Keener, James P

    2008-08-21

    Calcium (Ca(2+))-induced Ca(2+) release (CICR) is widely accepted as the principal mechanism linking electrical excitation and mechanical contraction in cardiac cells. The CICR mechanism has been understood mainly based on binding of cytosolic Ca(2+) with ryanodine receptors (RyRs) and inducing Ca(2+) release from the sarcoplasmic reticulum (SR). However, recent experiments suggest that SR lumenal Ca(2+) may also participate in regulating RyR gating through calsequestrin (CSQ), the SR lumenal Ca(2+) buffer. We investigate how SR Ca(2+) release via RyR is regulated by Ca(2+) and calsequestrin (CSQ). First, a mathematical model of RyR kinetics is derived based on experimental evidence. We assume that the RyR has three binding sites, two cytosolic sites for Ca(2+) activation and inactivation, and one SR lumenal site for CSQ binding. The open probability (P(o)) of the RyR is found by simulation under controlled cytosolic and SR lumenal Ca(2+). Both peak and steady-state P(o) effectively increase as SR lumenal Ca(2+) increases. Second, we incorporate the RyR model into a CICR model that has both a diadic space and the junctional SR (jSR). At low jSR Ca(2+) loads, CSQs are more likely to bind with the RyR and act to inhibit jSR Ca(2+) release, while at high SR loads CSQs are more likely to detach from the RyR, thereby increasing jSR Ca(2+) release. Furthermore, this CICR model produces a nonlinear relationship between fractional jSR Ca(2+) release and jSR load. These findings agree with experimental observations in lipid bilayers and cardiac myocytes. PMID:18538346

  7. Contribution of calcium oxalate to soil-exchangeable calcium

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2013-01-01

    Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that is not detected in standard measures of soil-exchangeable Ca. We asked whether several standard method extractants for soil-exchangeable Ca could also access Ca held in Ca oxalate crystals using spike recovery tests in both pure solutions and soil extractions. In solutions of the extractants ammonium chloride, ammonium acetate, and barium chloride, we observed 2% to 104% dissolution of Ca oxalate crystals, with dissolution increasing with both solution molarity and ionic potential of cation extractant. In spike recovery tests using a low-Ca soil, we estimate that 1 M ammonium acetate extraction dissolved sufficient Ca oxalate to contribute an additional 52% to standard measurements of soil-exchangeable Ca. However, in a high-Ca soil, the amount of Ca oxalate spike that would dissolve in 1 M ammonium acetate extraction was difficult to detect against the large pool of exchangeable Ca. We conclude that Ca oxalate can contribute substantially to standard estimates of soil-exchangeable Ca in acid forest soils with low soil-exchangeable Ca. Consequently, measures of exchangeable Ca are unlikely to fully resolve discrepancies in ecosystem Ca mass balance unless the contribution of Ca oxalate to exchangeable Ca is also assessed.

  8. Effect of the smear layer in the removal of calcium hydroxide from root canal walls

    Directory of Open Access Journals (Sweden)

    Hakan Arslan

    2012-01-01

    Full Text Available Background: The aim of this study was to investigate whether the smear layer influences the removal of calcium hydroxide from the root canal with manual or rotary instruments. Materials and Methods: The root canals of 48 freshly extracted single-rooted maxillary incisors were prepared to apical size 40 (n=40 and finally irrigated with sodium hypochlorite (group A, or ethylene diamine tetra acetic acid (EDTA followed by sodium hypo chlorite (group B. 20 teeth were assigned to each group, while the remaining eight teeth served as positive and negative controls. Each group was divided into two subgroups of 10 teeth (subgroup I - calcium hydroxide was removed with master apical file; subgroup II - with profile file; and, in all removal procedures, citric acid was used for irrigation. The percentage of calcium hydroxide-[Ca(OH [Ca(OH 2 ] coated surface area was calculated by image processing analysis. Results: Considering the root canal as a whole, the removal of Ca(OH 2 from the dentinal walls in group B showed significantly better results (P<0.05 as compared to group A. Conclusions: Under the conditions of this study, it can be concluded that the smear layer is important in the removal of calcium hydroxide.

  9. The effect of calcium and phosphorus supplementation on metabolic bone disorders in premature infants

    International Nuclear Information System (INIS)

    Objective: To determine the impact of calcium and phosphorus on radiological and biochemical characteristics of osteopenia in premature infants. Methods: The randomised clinical trial study was conducted at Valie-e-Asr Hospital of Zanjan city, Iran, from December 2010 to June 2011. It involved monitoring 40 premature neonates over a period of six months. The babies, who were fed with breast milk and 400 units of vitamin D daily, were randomly divided into two equal groups. One group received supplement of calcium and phosphorus. Serum calcium, phosphorus and alkaline phosphatase levels as well as growth parameters (including weight, height, and head circumference) were measured every two weeks. At the end of the study, wrist X-ray was done for evaluation of osteopenia. Data was analysed using SPSS 16. Results: Radiological changes, characteristic of osteopenia, were found in 8(40%) cases and 13(65%) controls (p<0.113). The mean of weight, length and head circumference increased significantly from second to sixth week during follow-up (p<0.0001). Phosphorus and alkaline phosphatase activity decreased significantly from second to sixth week of follow-up (p<0.02, p<0.01 respectively). However, repeated measurement analyses did not show significant effect of intervention in biochemical and growth parameters in the trial group. Conclusion: The study didn't show significant effect of calcium and phosphorus on prevention of osteopenia and improvement of growth. Further studies of longer duration and with different doses of supplement are recommended. (author)

  10. A theory of Plasma Membrane Calcium Pump stimulation and activity

    CERN Document Server

    Graupner, M; Meyer-Hermann, M; Erler, Frido; Graupner, Michael; Meyer-Hermann, Michael

    2003-01-01

    The ATP-driven Plasma Membrane Calcium (PMCA) pump is characterized by a high affinity to calcium and a low transport rate compared to other transmembrane calcium transport proteins. It plays a crucial role for calcium extrusion from cells. Calmodulin is an intracellular calcium buffering protein which is capable in its Calcium-liganded form to stimulate the PMCA pump by increasing both, the affinity to calcium and the maximum calcium transport rate. We introduce a new model of this stimulation process and deduce analytical expressions for experimental observables in order to determine the model parameter on the basis of specific experiments. Furthermore a model for the pumping activity is developed. In contrast to the biological process we have to describe the pumping rate behavior by assuming a ATP:Calcium stoichiometry of 2 in order to reproduce experimental data. The conjunction of the description of calcium pumping and the stimulation model fully and correctly simulates PMCA pump function. Therewith the ...

  11. The Incredible, Embryological Egg: Calcium and Strontium Isotopes Recapitulate Ontogeny

    Science.gov (United States)

    Gordon, G. W.; Skulan, J. L.

    2011-12-01

    Embryological development reflects evolutionary history. Understanding the processes of fetal growth is important for curing human birth defects and predicting damage to ecosystems from environmental insults. Tracing enzymatic and hormonal gradients during development, and correlating them to genetic cues dominate modern embryology. Previous work done tracing the mass transfer of elements has generally been limited to isotope spikes in vitro. Natural mass-dependent Ca and Sr isotopic ratios and radiogenic Sr isotopes have the potential to reveal both source and biochemical mechanism information about processes in vivo, but have not previously been extensively explored. The process when a hen lays a fertilized egg that becomes a chick includes formation and dissolution of calcium phosphate (bone) and calcium carbonate (shell). Skulan and DePaolo (1999) showed that chickens have 2% δ44/42Ca between a hen's bones and an egg white; this span represents more than 80% of the entire range of natural Ca isotope variation and illustrates there is significant variation to investigate. A striking feature of archosaurian development that also occurs in many mammals, including humans, is mass transfer of calcium from mother to embryo. The yolk of the domestic hen matures over 7-9 days, but the albumen, shell membranes and shell form in less than 20 hours. Domestic laying hens are at the physiological limit of egg production and selective breeding is no longer an effective method of increasing egg production. 60-75% of the shell's ~1.5 g of calcium comes from dietary sources, while 25-40% comes from the hen's medullary bone. Medullary bone is spicules formed in the marrow of long bones, and is a store of dietary calcium rapidly available for eggshell secretion. During in ovo development, the embryo's skeleton is formed from calcium in the yolk and by bulk dissolution of the eggshell's inner aspect via carbonic anhydrase in a process that has an effect on bone density similar to

  12. Oyster shell calcium induced parotid swelling

    Directory of Open Access Journals (Sweden)

    Muthiah Palaniappan

    2014-01-01

    Full Text Available A 59 year old female consumer was started on therapy with oyster shell calcium in combination with vitamin D3 and she presented with swelling below the ear, after two doses. She stopped the drug by herself and the swelling disappeared in one day. She started the drug one day after recovery and again she developed the swelling. She was advised to stop the drug with a suggestion to take lemon to enhance parotid secretion and the swelling subsided. Calcium plays major role in salivary secretion and studies have shown reduced parotid secretion in rats, deficient of vitamin D. But in humans involvement of calcium and vitamin D3 in parotid secretion is unknown. However, the patient had no history of reaction though she had previously taken vitamin D3 with calcium carbonate which was not from oyster shell. Hence, we ruled out vitamin D3 in this reaction and suspecting oyster shell calcium as a culprit. This adverse drug reaction (ADR was assessed using World Health Organization (WHO causality assessment, Naranjo′s and Hartwig severity scales. As per WHO causality assessment scale, the ADR was classified as "certain". This reaction was analyzed as per Naranjo′s algorithm and was classified as probable. According to Hartwig′s severity scale the reaction was rated as mild. Our case is an example of a mild but rare adverse effect of oyster shell calcium carbonate which is widely used.

  13. Membrane associated complexes in calcium dynamics modelling

    International Nuclear Information System (INIS)

    Mitochondria not only govern energy production, but are also involved in crucial cellular signalling processes. They are one of the most important organelles determining the Ca2+ regulatory pathway in the cell. Several mathematical models explaining these mechanisms were constructed, but only few of them describe interplay between calcium concentrations in endoplasmic reticulum (ER), cytoplasm and mitochondria. Experiments measuring calcium concentrations in mitochondria and ER suggested the existence of cytosolic microdomains with locally elevated calcium concentration in the nearest vicinity of the outer mitochondrial membrane. These intermediate physical connections between ER and mitochondria are called MAM (mitochondria-associated ER membrane) complexes. We propose a model with a direct calcium flow from ER to mitochondria, which may be justified by the existence of MAMs, and perform detailed numerical analysis of the effect of this flow on the type and shape of calcium oscillations. The model is partially based on the Marhl et al model. We have numerically found that the stable oscillations exist for a considerable set of parameter values. However, for some parameter sets the oscillations disappear and the trajectories of the model tend to a steady state with very high calcium level in mitochondria. This can be interpreted as an early step in an apoptotic pathway. (paper)

  14. Increased absolute calcium binding to albumin in hypoalbuminaemia.

    OpenAIRE

    Besarab, A; Caro, J F

    1981-01-01

    The amount of calcium bound to protein was measured in 30 patients with differing diseases and varying degrees of hypoalbuminaemia. Total serum calcium increased directly with both serum albumin and ultrafilterable calcium concentrations. The estimated amount of calcium bound per gram of albumin varied inversely with the albumin concentration, decreasing from 2.1 to 1.0 mg calcium/g albumin as albumin concentration increased from 1.7 to 3.1 g/dl. Circulating parathyroid hormone (PTH) concentr...

  15. The effect of dimethylsulfoxide on the calcium paradox.

    OpenAIRE

    Ruigrok, T. J.; Moes, D.; Slade, A.M.; Nayler, W. G.

    1981-01-01

    Reperfusion of isolated rat hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). Experiments were undertaken to study the effect of dimethylsulfoxide (DMSO) on the occurrence of the calcium paradox in rat heart muscle. DMSO (1.4 mol/l) was added to the calcium-free or the reperfusion medium. Cell damage was quantitated in terms of creatine kinase (CK) release, cardiac electrogram (CEG) changes, and ultras...

  16. Factors to consider in the selection of a calcium supplement.

    OpenAIRE

    Shangraw, R F

    1989-01-01

    Calcium supplements are widely used, yet many questions remain as to the absorption of various calcium salts. Because the solubility of many calcium salts is dependent upon pH, the type of salt used, the condition of the patient, and the time of administration should be considered. Studies show that many calcium supplements on the market today do not meet standards of quality established in the "U.S. Pharmacopeia" (USP). Consumers must be discerning about the products they purchase. Calcium s...

  17. Effect of calcium on adsorptive removal of As(III) and As(V) by iron oxide-based adsorbents

    KAUST Repository

    Uwamariya, V.

    2014-06-25

    The effects of calcium on the equilibrium adsorption capacity of As(III) and As(V) onto iron oxide-coated sand (IOCS) and granular ferric hydroxide (GFH) were investigated through batch experiments, rapid small-scale column tests (RSSCT) and kinetics modelling. Batch experiments showed that at calcium concentrations≤20 mg/L, high As(III) and As(V) removal efficiencies by IOCS and GFH are achieved at pH 6. An increase of the calcium concentration to 40 and 80 mg/L reversed this trend, giving higher removal efficiencies at higher pH (8). The adsorption capacities of IOCS and GFH at an equilibrium arsenic concentration of 10 g/L were found to be between 2.0 and 3.1 mg/g for synthetic water without calcium and between 2.8 and 5.3 mg/g when 80 mg/L of calcium was present at the studied pH values. After 10 hours of filter run in RSSCT, approximately 1000 empty bed volumes, the ratios of C/Co for As(V) were 26% and 18% for calcium-free model water; and only 1% and 0.2% after addition of 80 mg/L of Ca for filter columns with IOCS and GFH, respectively. The adsorption of As(III) and As(V) onto GFH follows a second-order reaction, with and without addition of calcium. The adsorption of As(III) and As(V) onto IOCS follows a first-order reaction without calcium addition, and moves to the second-reaction-order kinetics when calcium is added. Based on the intraparticle diffusion model, the main controlling mechanism for As(III) adsorption is intraparticle diffusion, while surface diffusion contributes greatly to the adsorption of As(V).

  18. Effect of combining different calcium concentration dialysate on calcium balance in peritoneal dialysis patients

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hui-ping; WU Bei; LU Li-xia; QIAO Jie; WU Xiang-lan; WANG Mei

    2012-01-01

    Background Calcium and phosphorus metabolic disturbance are common in dialysis patients and associated with increased morbidity and mortality.Therefore,maintaining the balance of calcium and phosphate metabolism and suitable intact parathyroid hormone(iPTH)level has become the focus of attention.We investigated the effects of different peritoneal dialysate calcium concentrations on calcium phosphate metabolism and iPTH in continuous ambulatory peritoneal dialysis(CAPD)patients.Methods Forty stable CAPD patients with normal serum calcium were followed for six months of treatment with 1.25 mmol/L calcium dialysate(DCa1.25,PD4,22 patients)or a combination of 1.75 mmol/L calcium dialysate(DCa1.75,PD2)and PD4(18 patients)twice a day respectively.Total serum calcium(after albumin correction),serum phosphorus,iPTH,alkaline phosphatase(ALP)and blood pressure were recorded before and 1,3 and 6 months after treatment commenced.Results No significant difference was found in baseline serum calcium,phosphorus between the two patient groups,but the levels of iPTH were significantly different.No significant changes were found in the dosage of calcium carbonate and active vitamin D during 6 months.In the PD4 group,serum calcium level at the 1st,3rd,6th months were significantly lower than the baseline(P<0.05).There was no significant difference in serum phosphorus after 6 months treatment.iPTH was significantly higher(P<0.001)at the 1st,3rd,and 6th months compared with the baseline.No differences were seen in ALP and blood pressure.In the PD4+PD2 group,no significant changes in serum calcium,phosphorus,iPTH,ALP and BP during the 6-month follow-up period.Conclusions Treatment with 1.25 mmol/L calcium dialysate for six months can decrease serum calcium,increase iPTH,without change in serum phosphorus,ALP,and BP.The combining of PD4 and PD2 can stabilize the serum calcium and avoid fluctuations in iPTH levels.

  19. Expanding the neuron's calcium signaling repertoire: intracellular calcium release via voltage-induced PLC and IP3R activation.

    Directory of Open Access Journals (Sweden)

    Stefanie Ryglewski

    2007-04-01

    Full Text Available Neuronal calcium acts as a charge carrier during information processing and as a ubiquitous intracellular messenger. Calcium signals are fundamental to numerous aspects of neuronal development and plasticity. Specific and independent regulation of these vital cellular processes is achieved by a rich bouquet of different calcium signaling mechanisms within the neuron, which either can operate independently or may act in concert. This study demonstrates the existence of a novel calcium signaling mechanism by simultaneous patch clamping and calcium imaging from acutely isolated central neurons. These neurons possess a membrane voltage sensor that, independent of calcium influx, causes G-protein activation, which subsequently leads to calcium release from intracellular stores via phospholipase C and inositol 1,4,5-trisphosphate receptor activation. This allows neurons to monitor activity by intracellular calcium release without relying on calcium as the input signal and opens up new insights into intracellular signaling, developmental regulation, and information processing in neuronal compartments lacking calcium channels.

  20. 40 CFR 418.11 - Specialized definitions.

    Science.gov (United States)

    2010-07-01

    ... in effect, as of the effective date of this regulation. (f) The term calcium sulfate storage pile..., abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart. (b) The term... regulation. (e) The term 25-year 24-hour rainfall event shall mean the maximum 24-hour precipitation...

  1. 40 CFR 415.34 - [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true 415.34 Section 415.34 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.34...

  2. Calcium homeostasis in barley aleurone

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.L.

    1990-02-21

    Under the auspices of the Department of Energy we investigated calcium homeostasis in aleurone cells of barley. This investigation was initiated to explore the role played by extracellular Ca{sup 2+} in gibberellic acid (GA)-induced synthesis and secretion of hydrolases in the aleurone layer. We have focused our attention on four topics that relate to the role of Ca{sup 2+} in regulating the synthesis of {alpha}-amylase. First, we determined the stoichiometry of Ca{sup 2+} binding to the two principal classes of barley {alpha}-amylase and examined some of the biochemical and physical properties of the native and Ca{sup 2+}-depleted forms of the enzyme. Second, since {alpha}-amylase is a Ca{sup 2+} containing metalloenzyme that binds one atom of Ca{sup 2+} per molecule, we developed methods to determine the concentration of Ca{sup 2+} in the cytosol of the aleurone cell. We developed a technique for introducing Ca{sup 2+}-sensitive dyes into aleurone protoplasts that allows the measurement of Ca{sup 2+} in both cytosol and endoplasmic reticulum (ER). Third, because the results of our Ca{sup 2+} measurements showed higher levels of Ca{sup 2+} in the ER than in the cytosol, we examined Ca{sup 2+} transport into the ER of control and GA-treated aleurone tissue. And fourth, we applied the technique of patch-clamping to the barley aleurone protoplast to examine ion transport at the plasma membrane. Our results with the patch-clamp technique established the presence of K{sup +} channels in the plasma membrane of the aleurone protoplast, and they showed that this cell is ideally suited for the application of this methodology for studying ion transport. 34 refs.

  3. Update on calcium pyrophosphate deposition.

    Science.gov (United States)

    Abhishek, Abhishek; Doherty, Michael

    2016-01-01

    Calcium pyrophosphate crystal deposition (CPPD) associates with ageing, osteoarthritis (OA), uncommon metabolic diseases, mutations and polymorphisms in the ankylosis human gene (ANKH). CPPD is frequently polyarticular, occurs due to a generalised articular predisposition, and the association between CPPD and OA is joint specific, for example CPPD associates with knee OA, but not with hip OA. Other recently identified associations include knee malalignment (knee CC), low cortical BMD and soft-tissue calcification. CPPD is generally asymptomatic. A recent study reported that knees with OA plus CC at the index joint, or at distant joints (in absence of index joint CC), were more likely to have attrition. CPPD can cause acute CPP crystal arthritis, chronic CPP crystal inflammatory arthritis, and is frequently present in joints with OA. Joint aspiration remains the gold standard for diagnosing CPPD, although other promising techniques are emerging. Patients with polyarticular or young onset CPPD should be screened for underlying metabolic abnormalities, however, such testing can be unrewarding. The treatment of CPPD is symptomatic. Acute CPP crystal arthritis is treated with rest, local application of ice-packs, joint aspiration, colchicine and/or intra-articular corticosteroid injection (once infection is excluded). Colchicine, low-dose corticosteroids, hydroxychloroquine and radiosynovectomy are recommended for the treatment of chronic or recurrent acute CPP crystal arthritis. Recent RCTs did not confirm any benefit from methotrexate, and although there is increasing interest in the use of anti-IL1 agents for acute or chronic CPP crystal arthritis, their efficacy has not been formally examined. Unlike gout, currently there are no treatments to eliminate CPP crystal deposits. PMID:27586801

  4. The L-Type Calcium Channel Blocker Nifedipine Impairs Extinction, but Not Reduced Contingency Effects, in Mice

    Science.gov (United States)

    Jami, Shekib; Barad, Mark; Cain, Christopher K.; Godsil, Bill P.

    2005-01-01

    We recently reported that fear extinction, a form of inhibitory learning, is selectively blocked by systemic administration of L-type voltage-gated calcium channel (LVGCC) antagonists, including nifedipine, in mice. We here replicate this finding and examine three reduced contingency effects after vehicle or nifedipine (40 mg/kg) administration.…

  5. The effect of GlycoPEGylation on the physical stability of human rFVIIa with increasing calcium chloride concentration

    DEFF Research Database (Denmark)

    Plesner, Bitten; Westh, Peter; Hvidt, Søren;

    2011-01-01

    The effects of calcium chloride on the structural, kinetic and thermal stability of recombinant human factor VIIa (rFVIIa) were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10 kDa PEG and a branched 40 kDa PEG, respectively. Three different CaCl(2...

  6. Eggshell powder, a comparable or better source of calcium than purified calcium carbonate: Piglet studies

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.

    1999-01-01

    Powdered chicken eggshells might be an interesting and widely available source of calcium. In two studies using piglets we determined the digestibility of calcium from different diets. The first study compared casein-based diets with CaCO3 (CasCC) or eggshell powder (CasES). The second study compare

  7. Calcium spikes and calcium plateaux evoked by differential polarization in dendrites of turtle motoneurones in vitro

    DEFF Research Database (Denmark)

    Hounsgaard, J; Kiehn, O

    1993-01-01

    The ability of dendrites in turtle motoneurones to support calcium spikes and calcium plateaux was investigated using differential polarization by applied electric fields. 2. Electric fields were generated by passing current through transverse slices of the turtle spinal cord between two plate......+ spikes and Ca2+ plateaux are present in dendrites of spinal motoneurones of the turtle....

  8. Characterization of dihydropyridine-sensitive calcium channels

    International Nuclear Information System (INIS)

    The structural and regulatory properties of the dihydropyridine-sensitive calcium channel were studied by isolating protein components of the channel complex from both cardiac and skeletal muscle. Hydrodynamic characterization of the (+)-(3H)PN200-110-labeled cardiac calcium channel revealed that the protein components of the complex had a total molecular mass of 370,000 daltons, a Stokes radius of 86 angstrom, and a frictional ratio of 1.3. A technique is described for the rapid incorporation of the CHAPS solubilized skeletal muscle calcium channel complex into phospholipid vesicles. 45Ca2+ uptake into phospholipid vesicles containing calcium channels was inhibited by phenylalkalamine calcium antagonists. Wheat germ lectin followed by DEAE chromatography of the CHAPS solubilized complex resulted in the dissociation of regulatory components of the complex from channel components. The DEAE preparation gave rise to 45Ca2+ uptake that was not inhibited by verapamil but was inhibited by GTPgS activated G0. The inhibition of 45Ca2+ uptake by verapamil was restored by co-reconstitution of wash fractions from wheat germ lectin chromatography. Phosphorylation of polypeptides in this fraction by polypeptide-dependent protein kinase prevented the restoration of verapamil sensitivity. The partial purification of an endogenous skeletal muscle ADP-ribosyltransferase is also described. ADP-ribosylation of the α2 subunit of the calcium channel complex is enhanced by polylysine and inhibited by GTPγS, suggesting that regulation of this enzyme is under the control of GTP binding proteins. These results suggest a complex model, involving a number of different protein components, for calcium channel regulation in skeletal muscle

  9. Papillary and Nonpapillary Calcium Oxalate Monohydrate Renal Calculi: Comparative Study of Etiologic Factors

    OpenAIRE

    Enrique Pieras; Antonia Costa-Bauz; Margarita Ramis; Felix Grases

    2006-01-01

    Calcium oxalate monohydrate (COM) renal calculi can be classified into two groups: papillary and nonpapillary. In this paper, a comparative study between etiologic factors of COM papillary and nonpapillary calculi is performed. The study included 40 patients with COM renal calculi. The urine of these individuals was analyzed. Case history, lifestyle, and dietetic habits were obtained.No significant differences between urinary biochemical data of both groups were observed; 50% of COM papillary...

  10. Synthesis and Sintering Character of Nanophase Calcium-deficient Apatite

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Nanophase calcium-deficient hydroxyapatite( CDHA ) with a Ca/P ratio about 1.5 synthesized by chemical wet method was sintered at different temperatures, and then its chemical composition, phase structure and morphology were analyzed with methods of FT- IR spectroscopy, X- ray diffraction (XRD) and field emission scanning microscopy (FESEM), respectively. Results shaw that when the sintering temperature is below 500 ℃ ,apatite crystal keeps a stable size with a diameter of 12-26 nm and a length of 30-66 nm. After being sintered at600 ℃ for 2 h, apatite crystal grows much larger with a diameter of 25-40 nm and a length of 75-100 nm. At the temperature of 700-800 ℃, this powder decomposes into Ca3 ( PO4 )2 - The crystal size of the Ca3 ( PO4 )2surpasses 200 nm in diameter and length. NH4+ ion can be removed at terrperature beyond 300 ℃ .

  11. Removal of Pb (II from Aqueous Solutions Using Mixtures of Bamboo Biochar and Calcium Sulphate, and Hydroxyapatite and Calcium Sulphate

    Directory of Open Access Journals (Sweden)

    Ahmed Hassan

    2016-01-01

    Full Text Available Sorption characteristics of Pb(II from aqueous solutions through a low-cost adsorbent mixture comprising of Bamboo biochar (BB and Calcium Sulphate (CS, and a more expensive mixture of Hydroxyapatite (HAP and Calcium Sulphate (CS, were investigated. The effects of equilibrium contact time, and adsorbate concentration conducted in batch experiments were studied. Adsorption equilibrium was established in 40 (min. The adsorption mechanism of Pb(II from these two adsorbent mixtures was carried out through a kinetic rate order. A pseudo second-order kinetic model was applied for the adsorption processes. The model yielded good correlation (R2 >0.999 of the experimental data. Adsorption of Pb(II using (BB&CS and (HAP&CS correlated well (R2 >0.99 with both the Langmuir and Freundlich isotherm equations under the concentration range studied. Hence, the effectiveness of an inexpensive natural material (BB&CS mixture in Pb(II removal is established, and is promising for use in other heavy metal adsorptions.

  12. Calcium ferrite formation from the thermolysis of calcium tris (maleato) ferrate(III)

    Indian Academy of Sciences (India)

    B S Randhawa; Kamaljeet Sweety

    2000-08-01

    For preparing calcium ferrite, calcium tris (maleato) ferrate(III) precursor was prepared by mixing aqueous solutions of iron(III) maleate, calcium maleate and maleic acid. Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to 900°C and ferrite formation. Three consecutive decomposition steps leading to the formation of -Fe2O3 and calcium carbonate have been observed at various stages of thermolysis. In the final stage the ferrite, Ca2Fe2O5, is obtained as a result of solid state reaction between -Fe2O3 and calcium carbonate at 788°C, a temperature much lower than for ceramic method. The results have been compared with those of the oxalate precursor.

  13. The physiological role of mitochondrial calcium revealed by mice lacking the mitochondrial calcium uniporter.

    Science.gov (United States)

    Pan, Xin; Liu, Jie; Nguyen, Tiffany; Liu, Chengyu; Sun, Junhui; Teng, Yanjie; Fergusson, Maria M; Rovira, Ilsa I; Allen, Michele; Springer, Danielle A; Aponte, Angel M; Gucek, Marjan; Balaban, Robert S; Murphy, Elizabeth; Finkel, Toren

    2013-12-01

    Mitochondrial calcium has been postulated to regulate a wide range of processes from bioenergetics to cell death. Here, we characterize a mouse model that lacks expression of the recently discovered mitochondrial calcium uniporter (MCU). Mitochondria derived from MCU(-/-) mice have no apparent capacity to rapidly uptake calcium. Whereas basal metabolism seems unaffected, the skeletal muscle of MCU(-/-) mice exhibited alterations in the phosphorylation and activity of pyruvate dehydrogenase. In addition, MCU(-/-) mice exhibited marked impairment in their ability to perform strenuous work. We further show that mitochondria from MCU(-/-) mice lacked evidence for calcium-induced permeability transition pore (PTP) opening. The lack of PTP opening does not seem to protect MCU(-/-) cells and tissues from cell death, although MCU(-/-) hearts fail to respond to the PTP inhibitor cyclosporin A. Taken together, these results clarify how acute alterations in mitochondrial matrix calcium can regulate mammalian physiology.

  14. Effect of dietary calcium and phosphorus on intestinal calcium absorption and vitamin D metabolism

    International Nuclear Information System (INIS)

    To understand better dietary regulation of intestinal calcium absorption, a quantitative assessment of the metabolites in plasma and duodenum of rats given daily doses of radioactive vitamin D3 and diets differing in calcium and phosphorus content was made. All known vitamin D metabolites were ultimately identified by high-pressure liquid chromatography. In addition to the known metabolites (25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D3, 25,26-dihydroxyvitamin D3, and 1,24,25-trihydroxyvitamin D3), several new and unidentified metabolites were found. In addition to 1,25-dihydroxyvitamin D3 and 1,24,25-trihydroxyvitamin D3, the levels of some of the unknown metabolites could be correlated with intestinal calcium transport. However, whether or not any of these metabolites plays a role in the stimulation of intestinal calcium absorption by low dietary calcium or low dietary phosphorus remains unknown

  15. Effects of Adding Chymosin to Milk on Calcium Homeostasis

    DEFF Research Database (Denmark)

    Møller, Ulla Kristine; Jensen, Lars Thorbjørn; Mosekilde, Leif;

    2014-01-01

    Calcium intake and absorption is important for bone health. In a randomized double-blind cross-over trial, we investigated effects of adding chymosin to milk on the intestinal calcium absorption as measured by renal calcium excretion and indices of calcium homeostasis. The primary outcome...... of the study was 24-h renal calcium excretion that is considered a proxy measure of the amount of calcium absorbed from the intestine. We studied 125 healthy men and women, aged 34 (25-45) years on two separate days. On each day, a light breakfast was served together with 500 ml of semi-skimmed milk to which...... not depend on plasma 25-hydroxyvitamin D levels. Chymosin added to milk increases renal calcium excretion in the hours following intake without affecting plasma levels of calcium or calciotropic hormones. The effect most likely represents enhanced intestinal calcium absorption shortly after intake. Further...

  16. Role of mitochondria and network connectivity in intercellular calcium oscillations

    CERN Document Server

    Dokukina, I V; Grachev, E A; Gunton, J D; Dokukina, Irina V.; Gracheva, Maria E.; Grachev, Eugene A.; Gunton, James D.

    2005-01-01

    Mitochondria are large-scale regulators of cytosolic calcium under normal cellular conditions. In this paper we model the complex behavior of mitochondrial calcium during the action of inositol 1,4,5-trisphosphate on a single cell and find results that are in good agreement with recent experimental studies. We also study the influence of the cellular network connectivity on intercellular signalling via gap junction diffusion. We include in our model the dependence of the junctional conductivity on the cytosolic calcium concentrations in adjacent cells. We consider three different mechanisms of calcium wave propagation through gap junctions: via calcium diffusion, inositol 1,4,5-trisphosphate diffusion, and both calcium and inositol 1,4,5-trisphosphate diffusion. We show that inositol 1,4,5-trisphosphate diffusion is the mechanism of calcium wave propagation and that calcium diffusion is the mechanism of synchronization of cytosolic calcium oscillations in adjacent cells. We also study the role of different to...

  17. THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

    Institute of Scientific and Technical Information of China (English)

    Qing-shan Kong; Bing-bing Wang; Quan Ji; Yan-zhi Xia; Zhao-xia Guo; Jian Yu

    2009-01-01

    Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride. The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry (TG), X-ray diffraction (XRD), limiting oxygen index (LOI) and cone calorimeter (CONE). The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34, and the heat release rate (HRR), total heat release (THR), CO and CO_2 concentrations during combustion are much lower compared with those of viscose fibers. Calcium carbonate and calcium oxide were formed during thermal degradation of calcium alginate fibers at different temperatures. The shape of calcium alginate fibers is well kept after LOI test. The rigid combustion residue char acts as an effective barrier to the outward diffusion of flame and heat. The combustion process and flame retardant mechanism of calcium alginate fibers are also discussed.

  18. Role of calcium in gravity perception of plant roots

    Science.gov (United States)

    Evans, Michael L.

    1986-01-01

    Calcium ions may play a key role in linking graviperception by the root cap to the asymmetric growth which occurs in the elongation zone of gravistimulated roots. Application of calcium-chelating agents to the root cap inhibits gravitropic curvature without affecting growth. Asymmetric application of calcium to one side of the root cap induces curvature toward the calcium source, and gravistimulation induces polar movement of applied (Ca-45)(2+) across the root cap toward the lower side. The action of calcium may be linked to auxin movement in roots since: (1) auxin transport inhibitors interfere both with gravitropic curvature and graviinduced polar calcium movement and (2) asymmetric application of calcium enhances auxin movement across the elongation zone of gravistimulated roots. Indirect evidence indicates that the calcium-modulated regulator protein, calmodulin, may be involved in either the transport or action of calcium in the gravitropic response mechanism of roots.

  19. Role of calcium in gravity perception of plant roots

    Science.gov (United States)

    Evans, Michael L.

    Calcium ions may play a key role in linking graviperception by the root cap to the asymmetric growth which occurs in the elongation zone of gravistimulated roots. Application of calcium-chelating agents to the root cap inhibits gravitropic curvature without affecting growth. Asymmetric application of calcium to one side of the root cap induces curvature toward the calcium source, and gravistimulation induces polar movement of applied 45Ca2+ across the root cap toward the lower side. The action of calcium may be linked to auxin movement in roots since 1) auxin transport inhibitors interfere both with gravitropic curvature and gravi-induced polar calcium movement and 2) asymmetric application of calcium enhances auxin movement across the elongation zone of gravistimulated roots. Indirect evidence indicates that the calcium-modulated regulator protein, calmodulin, may be involved in either the transport or action of calcium in the gravitropic response mechanism of roots.

  20. Effects of calcium gluconate on the utilization of magnesium and the nephrocalcinosis in rats fed excess dietary phosphorus and calcium.

    Science.gov (United States)

    Chonan, O; Takahashi, R; Kado, S; Nagata, Y; Kimura, H; Uchida, K; Watanuki, M

    1996-08-01

    The effects of calcium gluconate on the utilization of magnesium and nephrocalcinosis in male Wistar rats made magnesium-deficient by adding excess dietary phosphorus (1.195 g of phosphorus/100 g of diet) and calcium (1.04 g of calcium/100 g of diet) were compared with the effects of calcium carbonate. The effects of dietary magnesium concentration on the magnesium status and nephrocalcinosis were also examined. Adding excess dietary phosphorus and calcium decreased the apparent magnesium absorption ratios and the concentrations of magnesium in the serum and femur and increased the deposition of calcium in the kidney, and the low magnesium condition (0.024 g of magnesium/100 g of diet) aggravated the deposition of calcium and the low magnesium status. The apparent magnesium absorption ratios and femur magnesium concentration in the rats fed a calcium gluconate diet (an equimolar mixture of calcium gluconate and calcium carbonate was used as a source of calcium) were significantly higher than in the rats fed a calcium carbonate diet (only calcium carbonate was used as a source of calcium), irrespective of dietary magnesium concentration. Dietary calcium gluconate lessened the accumulation of calcium in the kidney and increased the serum magnesium concentration compared with dietary calcium carbonate, when the rats were fed the normal magnesium diet (0.049 g of magnesium/100 g of diet) but not the low magnesium diet. We speculate that the increased utilization of magnesium by feeding the calcium gluconate diet to a limited extent prevented the low magnesium status and the severity of nephrocalcinosis caused by adding excess dietary phosphorus and calcium.

  1. Information flow through calcium binding proteins

    Science.gov (United States)

    Bak, Ji Hyun; Bialek, William

    2013-03-01

    Calcium signaling is a ubiquitous mode of biological communication, which regulates a great variety of vital processes in living systems. Such a signal typically begins with an elementary event, in which calcium ions bind to a protein, inducing a change in the protein's structure. Information can only be lost, from what was conveyed through this initial event, as the signal is further transduced through the downstream networks. In the present work we analyze and optimize the information flow in the calcium binding process. We explicitly calculate the mutual information between the calcium concentration and the states of the protein, using a simple model for allosteric regulation in a dimeric protein. The optimal solution depends on the dynamic range of the input as well as on the timescale of signal integration. According to our result, the optimizing strategy involves allowing the calcium-binding protein to be ``activated'' by a partial occupation of its sites, and tuning independently the strengths of cooperative interactions in the binding and unbinding processes.

  2. Calcium's Role in Mechanotransduction during Muscle Development

    Directory of Open Access Journals (Sweden)

    Tatiana Benavides Damm

    2014-01-01

    Full Text Available Mechanotransduction is a process where cells sense their surroundings and convert the physical forces in their environment into an appropriate response. Calcium plays a crucial role in the translation of such forces to biochemical signals that control various biological processes fundamental in muscle development. The mechanical stimulation of muscle cells may for example result from stretch, electric and magnetic stimulation, shear stress, and altered gravity exposure. The response, mainly involving changes in intracellular calcium concentration then leads to a cascade of events by the activation of downstream signaling pathways. The key calcium-dependent pathways described here include the nuclear factor of activated T cells (NFAT and mitogen-activated protein kinase (MAPK activation. The subsequent effects in cellular homeostasis consist of cytoskeletal remodeling, cell cycle progression, growth, differentiation, and apoptosis, all necessary for healthy muscle development, repair, and regeneration. A deregulation from the normal process due to disuse, trauma, or disease can result in a clinical condition such as muscle atrophy, which entails a significant loss of muscle mass. In order to develop therapies against such diseased states, we need to better understand the relevance of calcium signaling and the downstream responses to mechanical forces in skeletal muscle. The purpose of this review is to discuss in detail how diverse mechanical stimuli cause changes in calcium homeostasis by affecting membrane channels and the intracellular stores, which in turn regulate multiple pathways that impart these effects and control the fate of muscle tissue.

  3. Calcium and bone disorders in pregnancy

    Directory of Open Access Journals (Sweden)

    Shriraam Mahadevan

    2012-01-01

    Full Text Available Significant transplacental calcium transfer occurs during pregnancy, especially during the last trimester, to meet the demands of the rapidly mineralizing fetal skeleton. Similarly, there is an obligate loss of calcium in the breast milk during lactation. Both these result in considerable stress on the bone mineral homeostasis in the mother. The maternal adaptive mechanisms to conserve calcium are different in pregnancy and lactation. During pregnancy, increased intestinal absorption of calcium from the gut mainly due to higher generation of calcitriol (1,25 dihydroxy vitamin D helps in maintaining maternal calcium levels. On the other hand, during lactation, the main compensatory mechanism is skeletal resorption due to increased generation of parathormone related peptide (PTHrP from the breast. Previous studies suggest that in spite of considerable changes in bone mineral metabolism during pregnancy, parity and lactation are not significantly associated with future risk for osteoporosis. However, in India, the situation may not be the same as a significant proportion of pregnancies occur in the early twenties when peak bone mass is not yet achieved. Further, malnutrition, anemia and vitamin D deficiency are commonly encountered in this age group. This may have an impact on future bone health of the mother. It may also probably provide an opportunity for health care providers for prevention. Other metabolic bone diseases like hypoparathyroidism, hyperparathyroidism and pseudohypoparathyroidism are rarely encountered in pregnancy. Their clinical implications and management are also discussed.

  4. Calcium And Zinc Deficiency In Preeclamptic Women

    Directory of Open Access Journals (Sweden)

    Sultana Ferdousi

    2011-12-01

    Full Text Available Background: Pre-eclampsia is the most common medical complication of pregnancy associated withincreased maternal and infant mortality and morbidity. Reduced serum calcium and zinc levels arefound associated with elevated blood pressure in preeclampsia. Objective: To observe serum calciumand zinc levels in preeclamptic women. Methods: This cross sectional study was carried out in theDepartment of Physiology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka betweenJuly 2009 to June 2010. In this study, 60 pregnant women of preeclampsia, aged 18-39 years withgestational period more than 20th weeks were included as the study (group B. For comparison ageand gestational period matched 30 normotensive pregnant women control (group A were also studied.All the subjects were selected from Obstetric and Gynae In and Out patient Department of BSMMUand Dhaka Medical College Hospital. Serum calcium was measured by Colorimetric method and serumzinc was measured by Spectrophotometric method. Data were analysed by independent sample t testand Pearson’s correlation coefficient test. Results: Mean serum calcium and zinc levels weresignificantly (p<0.001 lower in study group than those of control group. Again, serum calcium andzinc showed significant negative correlation with SBP and DBP in preeclamptic women. Conclusion:This study concludes that serum calcium and zinc deficiency may be one of the risk factor ofpreeclampsia. Therefore, early detection and supplementation to treat this deficiency may reduce theincidence of preeclampsia.

  5. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    Science.gov (United States)

    Rathod, Anita; Bonny, Olivier; Guessous, Idris; Suter, Paolo M.; Conen, David; Erne, Paul; Binet, Isabelle; Gabutti, Luca; Gallino, Augusto; Muggli, Franco; Hayoz, Daniel; Péchère-Bertschi, Antoinette; Paccaud, Fred

    2015-01-01

    Background and objectives Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. Design, settings, participants, & measurements Multivariable linear regression was used to explore factors associated with square root–transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dependent variable with a focus on month-specific vitamin D tertiles and serum calcium in the Swiss Survey on Salt Study. Results In total, 624 men and 669 women were studied with mean ages of 49.2 and 47.0 years, respectively (age range=15–95 years). Mean urinary calcium excretion was higher in men than in women (183.05 versus 144.60 mg/24 h; P<0.001). In adjusted models, the association (95% confidence interval) of square root urinary calcium excretion with protein–corrected serum calcium was 1.78 (95% confidence interval, 1.21 to 2.34) mg/24 h per milligram per deciliter in women and 0.59 (95% confidence interval, −0.11 to 1.29) mg/24 h per milligram per deciliter in men. Men in the third 25(OH)D3 tertile had higher square root urinary calcium excretion than men in the first tertile (0.99; 95% confidence interval, 0.36 to 1.63 mg/24 h per nanogram per milliliter), and the corresponding association was 0.32 (95% confidence interval, −0.22 to 0.85) mg/24 h per nanogram per milliliter in women. These sex differences were more marked under conditions of high urinary sodium or urea excretions. Conclusions There was a positive association of serum calcium with urinary calcium excretion in women but not men. Vitamin 25(OH)D3 was associated with urinary calcium excretion in men but not women. These results suggest important sex differences in the hormonal and dietary control of urinary calcium excretion. PMID:25518946

  6. Single atom detection of calcium isotopes by atom trap trace analysis

    CERN Document Server

    Hoekstra, S; Morgenstern, R; Wilschut, H W; Hoekstra, R

    2005-01-01

    We demonstrate a combination of an isotopically purified atom beam and a magneto-optical trap which enables the single atom detection of all stable isotopes of calcium (40, 42, 43, 44, 46 and 48). These isotopes range in abundance from 96.9 % (40Ca) to 0.004 (46Ca). The trap is loaded from an atomic beam which is decelerated in a Zeeman slower and subsequently deflected over an angle of 30 degrees by optical molasses. The isotope selectivity of the Zeeman slower and the deflection stage is investigated experimentally and compared with Monte Carlo simulations.

  7. OSTEOPOROSIS IN CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITION DISEASE

    Directory of Open Access Journals (Sweden)

    S A Vladimirov

    2013-01-01

    Full Text Available Objective: to study the incidence of osteoporosis (OP in patients with calcium pyrophosphate crystal deposition disease (CPCDD. Subjects and methods. Eighty patients with CPCDD were examined. Bone mineral density (BMD of the forearm, lumbar spine, and femoral neck was determined by dual-energy X-ray absorptiometry. Laboratory diagnosis involved determination of the blood levels of C-reactive protein, parathyroid hormone, calcium, magnesium, and phosphorus and the daily urinary excretion of calcium and phosphates. Results. The patients with OP were significantly older than those with normal BMD and osteopenia. Forearm bones were the most common isolated location of OP and osteopenia. Injuries in the history, traumatic fractures, and the intake of diuretics were somewhat more common in the patients diagnosed with OP. The incidence of hyperparathyroidism did not differ significantly in the groups.

  8. Glial calcium signaling in physiology and pathophysioilogy

    Institute of Scientific and Technical Information of China (English)

    Alexei VERKHRASKY

    2006-01-01

    Neuronal-glial circuits underlie integrative processes in the nervous system.Function of glial syncytium is,to a very large extent,regulated by the intracellular calcium signaling system.Glial calcium signals are triggered by activation of multiple receptors,expressed in glial membrane,which regulate both Ca2+ entry and Ca2+ release from the endoplasmic reticulum.The endoplasmic reticulum also endows glial cells with intracellular excitable media,which is able to produce and maintain long-ranging signaling in a form of propagating Ca2+ waves.In pathological conditions,calcium signals regulate glial response to injury,which might have both protective and detrimental effects on the nervous tissue.

  9. Calcium carbide poisoning via food in childhood.

    Science.gov (United States)

    Per, Hüseyin; Kurtoğlu, Selim; Yağmur, Fatih; Gümüş, Hakan; Kumandaş, Sefer; Poyrazoğlu, M Hakan

    2007-02-01

    The fast ripening of fruits means they may contain various harmful properties. A commonly used agent in the ripening process is calcium carbide, a material most commonly used for welding purposes. Calcium carbide treatment of food is extremely hazardous because it contains traces of arsenic and phosphorous. Once dissolved in water, the carbide produces acetylene gas. Acetylene gas may affect the neurological system by inducing prolonged hypoxia. The findings are headache, dizziness, mood disturbances, sleepiness, mental confusion, memory loss, cerebral edema and seizures. We report the case of a previously healthy 5 year-old girl with no chronic disease history who was transferred to our Emergency Department with an 8-h history of coma and delirium. A careful history from her father revealed that the patient ate unripe dates treated with calcium carbide.

  10. Impairment of ciprofloxacin absorption by calcium polycarbophil.

    Science.gov (United States)

    Kato, Ryuji; Ueno, Kazuyuki; Imano, Hideki; Kawai, Masayuki; Kuwahara, Shiro; Tsuchishita, Yoshimasa; Yonezawa, Emi; Tanaka, Kazuhiko

    2002-07-01

    The effect of calcium polycarbophil on the absorption of ciprofloxacin, a broad-spectrum antibacterial agent, was evaluated in an in vitro and in vivo study. In the in vitro study, the release of ciprofloxacin from the cellulose membrane in the presence or absence of metal cations was measured using the dissolution test procedure. In the in vivo study, male ST Wistar rats and male volunteers were employed. First, 20 mg/kg of ciprofloxacin alone (Rat Study 1) or 20 mg/kg of ciprofloxacin in combination with 64 mg/kg of calcium chloride (Rat Study 2) was administered orally to 3 rats. Second, a volunteer study was employed and a randomized crossover design with twophases was used. In onephase, volunteers received 400 mg of ciprofloxacin alone (Study 1); in the other phase, they received 400 mg of ciprofloxacin and 1200 mg of fine calcium polycarbophil granules concomitantly (Study 2). The plasma and serum concentrations of ciprofloxacin were measured by high-performance liquid chromatography. The release of ciprofloxacin from the cellulose membrane in the presence of aluminum, calcium, or iron ions was slower than that in the absence of these metal ions. The AUC0-4 and Cmax in Rat Study 2 were lower than those respective values in Rat Study 1. AUC0-4 was approximately 60% lower in Rat Study 2 than Rat Study 1. In the volunteer study, the AUC0-12 and Cmax in Study 2 were lower than those respective values in Study 1. In particular, AUC0-12 was approximately 50% lowerin Study 2 than in Study 1. These findings suggest that when ciprofloxacin and calcium polycarbophil were coadministered concomitantly, a decrease of ciprofloxacin absorption was observed, and this action was caused by the formation of chelate complexes. Therefore, it seems clear that we should avoid the concomitant administration of ciprofloxacin and calcium polycarbophil.

  11. Characterization of Calcium Compounds in Opuntia ficus indica as a Source of Calcium for Human Diet

    Directory of Open Access Journals (Sweden)

    Isela Rojas-Molina

    2015-01-01

    Full Text Available Analyses of calcium compounds in cladodes, soluble dietary fiber (SDF, and insoluble dietary fiber (IDF of Opuntia ficus indica are reported. The characterization of calcium compounds was performed by using Scanning Electron Microscopy, Energy Dispersive Spectrometry, X-ray diffraction, and infrared spectroscopy. Atomic Absorption Spectroscopy and titrimetric methods were used for quantification of total calcium and calcium compounds. Whewellite (CaC2O4·H2O, weddellite (CaC2O4·(H2O2.375, and calcite (CaCO3 were identified in all samples. Significant differences (P≤0.05 in the total calcium contents were detected between samples. CaC2O4·H2O content in cladodes and IDF was significantly higher (P≤0.05 in comparison to that observed in SDF, whereas minimum concentration of CaCO3 was detected in IDF with regard to CaCO3 contents observed in cladodes and SDF. Additionally, molar ratio oxalate : Ca2+ in all samples changed in a range from 0.03 to 0.23. These results support that calcium bioavailability in O. ficus indica modifies according to calcium compounds distribution.

  12. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    Science.gov (United States)

    Komar, Nemanja; Zeebe, Richard

    2016-04-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here, we identify the deficiencies of a simplified calcium model employed in several previous studies and we demonstrate the importance of a fully coupled carbon-cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the LOSCAR model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6oC.

  13. ALG-2, a multifunctional calcium binding protein?

    DEFF Research Database (Denmark)

    Tarabykina, Svetlana; Mollerup, Jens; Winding Gojkovic, P.;

    2004-01-01

    ALG-2 was originally discovered as a pro-apoptotic protein in a genetic screen. Due to its ability to bind calcium with high affinity it was postulated to provide a link between the known effect of calcium in programmed cell death and the molecular death execution machinery. This review article...... discusses the current knowledge on the structure and potential function of this protein. Several putative binding partners of ALG-2 have been identified hinting to functions of ALG-2 in apoptosis and possibly also in proliferation, endocytosis and transcriptional regulation during development. Gene deletion...

  14. NMR study of hydrated calcium silicates

    International Nuclear Information System (INIS)

    Radioactive wastes storage methods are developed by the CEA. As cements are important materials as well for hours living radioisotopes than for years living radioisotopes, a better knowledge of this material will allow to anticipate its behaviour and to obtain safer storage methods. The structure of calcium silicates (C-S-H) (main constituent of cements) have then been determined in this thesis by nuclear magnetic resonance. This method has allow to explain in structural terms, the different calcium rates that can be measured in the C-S-H too. (O.M.)

  15. Calcium and weight control-Publications summaries

    Directory of Open Access Journals (Sweden)

    Feride Çelebi

    2011-08-01

    Full Text Available Obesity is a public health problem. And it is known that both energy balance and nutritional factors are effective on it. The effects of dietary calcium on bone health are known however with recent studies, it has become a food item that focused on the effect on body weight control. Most epidemiyolojik studies claim that there is a relationship between long-term consumption of diary milk and milk products and the decrease of body weight and fat mass. In this article, there are different studies that support or do not support this idea. However the effect mechanism of calcium on weight control is tried to be explained.

  16. Dietary calcium intake and Renin Angiotensin System polymorphisms alter the blood pressure response to aerobic exercise: a randomized control design

    Directory of Open Access Journals (Sweden)

    Tsongalis Gregory J

    2007-01-01

    Full Text Available Abstract Background Dietary calcium intake and the renin angiotensin system (RAS regulate blood pressure (BP by modulating calcium homeostasis. Despite similar BP regulatory effects, the influence of dietary calcium intake alone and combined with RAS polymorphisms on the BP response following acute aerobic exercise (i.e., postexercise hypotension has not been studied. Thus, we examined the effect of dietary calcium intake and selected RAS polymorphisms on postexercise hypotension. Methods Subjects were men (n = 50, 43.8 ± 1.3 yr with high BP (145.3 ± 1.5/85.9 ± 1.1 mm Hg. They completed three experiments: non-exercise control and two cycle bouts at 40% and 60% of maximal oxygen consumption (VO2max. Subjects provided 3 d food records on five protocol-specific occasions. Dietary calcium intake was averaged and categorized as low (1R A/C were analyzed with molecular methods. Genotypes were reduced from three to two: ACE II/ID and ACE DD; or AT1R AA and AT1R CC/AC. Repeated measure ANCOVA tested if BP differed among experiments, dietary calcium intake level and RAS polymorphisms. Results Systolic BP (SBP decreased 6 mm Hg after 40% and 60% VO2max compared to non-exercise control for 10 h with LowCa (p 2max versus non-exercise control for 10 h among ACE II/ID (6 mm Hg and AT1R AA (8 mm Hg; and by 8 mm Hg after 40% VO2max among ACE DD and AT1R CC/CA (p 2max compared to non-exercise control for 10 h (p 2max (p ≥ 0.05. Conclusion SBP decreased after exercise compared to non-exercise control among men with low but not high dietary calcium intake. Dietary calcium intake interacted with the ACE I/D and AT1R A/C polymorphisms to further modulate postexercise hypotension. Interactions among dietary calcium intake, exercise intensity and RAS polymorphisms account for some of the variability in the BP response to exercise.

  17. Avian eggshell formation in calcium-rich and calcium-poor habitats: Importance of snail shells and anthropogenic calcium sources

    NARCIS (Netherlands)

    Graveland, J.

    1996-01-01

    Most passerines depend on the intake of calcium-rich material in addition to their normal food for proper eggshell formation and skeletal growth. A large proportion of Great Tits (Pants major) in forests on nutrient-poor soils in the Netherlands produce eggs with defective shells as a result of calc

  18. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins

    DEFF Research Database (Denmark)

    Hsu, Yu-Juei; Dimke, Henrik Anthony; Schoeber, Joost P H;

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had....... Androgen deficiency increased the abundance of the renal mRNA and protein of both the luminal transient receptor potential vanilloid-subtype 5 (TRPV5) and intracellular calbindin-D(28K) transporters, which in turn were suppressed by testosterone treatment. There were no significant differences in serum...

  19. Light particle coincidences with gross structure in energy spectra from the 40Ca+40Ca collision

    International Nuclear Information System (INIS)

    Angular correlations between light charged particles and heavy ion fragments from the 40Ca + 40Ca collision have been investigated. The high excitation energy structure previously observed in inclusive experiments is strongly populated in coincidence with protons for calcium and potassium fragments, with alphas for argon fragments. Particles emitted in coincidence with the structure are strongly focused and have a velocity close to the velocity of the beam, whereas the yield of evaporation decay is very small

  20. Calcium Supplements Might Raise Older Women's Dementia Risk

    Science.gov (United States)

    ... nutrient," she said. "For example, calcium, phosphorus and magnesium all are typically looked at for their effects ... which was not originally designed to assess calcium intake," MacKay noted. "Further, the new analysis included only ...

  1. Intolerance to oral and intravenous calcium supplements in atopic eczema.

    OpenAIRE

    Devlin, J; David, T J

    1990-01-01

    Children treated with dietary restriction for food intolerance may require calcium supplementation, particularly if cows' milk and milk substitutes are not tolerated. We report two children with atopic eczema who reacted adversely to a number of calcium supplement formulations.

  2. A sequential injection system for the spectrophotometric determination of calcium, magnesium and alkalinity in water samples.

    Science.gov (United States)

    Mesquita, Raquel B R; Rangel, António O S S

    2004-08-01

    A sequential injection methodology for the spectrophotometric determination of calcium, magnesium and alkalinity in water samples is proposed. A single manifold is used for the determination of the three analytes, and the same protocol sequence allows the sequential determination of calcium and magnesium (the sum corresponds to the water hardness). The determination of both metals is based on their reaction with cresolphtalein complexone; mutual interference is minimized by using 8-hydroxyquinoline for the determination of calcium and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) for the determination of magnesium. Alkalinity determination is based on a reaction with acetic acid, and corresponding color change of Bromcresol Green. Working ranges of 0.5 - 5 mg dm(-3) for Ca, 0.5 - 10 mg dm(-3) for Mg, and 10 - 100 mg HCO3- dm(-3), for alkalinity have been achieved. The results for water samples were comparable to those of the reference methods and to a certified reference water sample. RSDs lower than 5% were obtained, a low reagent consumption and a reduced volume of effluent have been accomplished. The determination rate for calcium and magnesium is 80 h(-1), corresponding to 40 h(-1) per element, while 65 determinations of alkalinity per hour could be carried out.

  3. Biomimetic Nanocomposites of Calcium Phosphate and Self-Assembling Triblock and Pentablock Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Drew Lenzen Enlow

    2006-08-09

    In an effort to mimic the growth of natural bone, self-assembling, micelle and gel-forming copolymers were used as a template for calcium phosphate precipitation. Because of the cationic characteristics imparted by PDEAEM end group additions to commercially available Pluronic{reg_sign} Fl27, a direct ionic attraction mechanism was utilized and a polymer-brushite nanocomposite spheres were produced. Brushite coated spherical micelles with diameters of {approx}40 nm, and agglomerates of these particles (on the order of 0.5 {mu}m) were obtained. Thickness and durability of the calcium phosphate coating, and the extent of agglomeration were studied. The coating has been shown to be robust enough to retain its integrity even below polymer critical micelle concentration and/or temperature. Calcium phosphate-polymer gel nanocomposites were also prepared. Gel samples appeared as a single phase network of agglomerated spherical micelles, and had a final calcium phosphate concentration of up to 15 wt%. Analysis with x-ray diffraction and NMR indicated a disordered brushite phase with the phosphate groups linking inorganic phase to the polymer.

  4. Calcium transport, thiol status, and hepatotoxicity following N-nitrosodimethylamine exposure in mice

    Energy Technology Data Exchange (ETDEWEB)

    Reitman, F.A.; Berger, M.L.; Minnema, D.J.; Shertzer, H.G.

    1988-01-01

    The hepatotoxicant N-nitrosodimethylamine (NDMA) is presumed to exert toxicity through reactive metabolites. NDMA is similar in this respect to numerous other hepatotoxicants, for which hepatotoxicity is also associated with a rapid depletion of soluble and/or protein thiols, and an inhibition of calcium transport systems. The authors examined the hypothesis that hepatotoxicity for NDMA is preceded by thiol depletion and/or inhibition of calcium transport in isolated liver subcellular fractions. Centrizonal liver necrosis in mice was evident at 24 but not at 12 h subsequent to intraperitoneal administration of 40 mg NDMA/kg. Hepatotoxicity was not preceded by depletion of liver protein-free sulfhydryls, nor by protein sulfhydryl depletion in liver whole homogenate, microsomal, or plasma membrane fractions. NDMA-mediated toxicity was also not preceded by inhibition of calcium uptake capability by microsomal, mitochondrial, or plasma membrane fractions. In contrast, carbon tetrachloride produced the expected rapid decrease in microsomal calcium uptake capability, followed by a centrizonal necrosis that was maximal at about 24 h. These studies suggest that the mechanism of NDMA hepatotoxicity may differ from that of a number of other hepatotoxicants (e.g., carbon tetrachloride, acetaminophen, bromobenzene) for which toxicity is also mediated through reactive metabolites.

  5. Biomimetic Nanocomposites of Calcium Phosphate and Self-Assembling Triblock and Pentablock Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Enlow, Drew Lenzen [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    In an effort to mimic the growth of natural bone, self-assembling, micelle and gel-forming copolymers were used as a template for calcium phosphate precipitation. Because of the cationic characteristics imparted by PDEAEM end group additions to commercially available Pluronic{reg_sign} Fl27, a direct ionic attraction mechanism was utilized and a polymer-brushite nanocomposite spheres were produced. Brushite coated spherical micelles with diameters of ~40 nm, and agglomerates of these particles (on the order of 0.5 μm) were obtained. Thickness and durability of the calcium phosphate coating, and the extent of agglomeration were studied. The coating has been shown to be robust enough to retain its integrity even below polymer critical micelle concentration and/or temperature. Calcium phosphate-polymer gel nanocomposites were also prepared. Gel samples appeared as a single phase network of agglomerated spherical micelles, and had a final calcium phosphate concentration of up to 15 wt%. Analysis with x-ray diffraction and NMR indicated a disordered brushite phase with the phosphate groups linking inorganic phase to the polymer.

  6. Inulin and fructooligosaccharide affect in vitro calcium uptake and absorption from calcium-enriched gluten-free bread.

    Science.gov (United States)

    Krupa-Kozak, U; Swiątecka, D; Bączek, N; Brzóska, M M

    2016-04-01

    Compromised intestinal calcium absorption affecting a deterioration of bone state is a sign of coeliac disease. Experimental calcium-fortified gluten-free bread (GFB) of improved calcium bioavailability could increase calcium content in the diets of coeliac disease patients, allowing them to obtain the amount of calcium they need for therapeutic use. Prebiotics, including inulin-type fructans (IFs) have a beneficial effect on calcium bioavailability. In the present study, the in vitro model composed of the intestinal-like Caco-2 cells and the human intestinal bacteria (Lactobacillus, Enterococcus and Enterobacteriaceae) were used to analyse the effect of inulin and fructooligosaccharide (FOS) of different chain lengths, on calcium uptake and absorption from experimental GFB. Analysed IFs, especially short-chain FOS, significantly (p < 0.05) increased cellular calcium uptake from GFB digest and stimulated the intestinal bacteria applied in the cultures to the intensive synthesis of organic acids. In particular, the concentration of butyric, valeric and lactic acids increased significantly. Similarly, in the calcium absorption experiment, IFs increased the cellular calcium retention but concomitantly reduced its content in basolateral filtrates. The results obtained suggest that the applied IFs affected differentially calcium uptake and absorption from the experimental calcium-enriched GFB, therefore a further study is needed to assess whether these observations made in vitro contribute to IF effects on calcium absorption from experimental GFB in vivo.

  7. Inulin and fructooligosaccharide affect in vitro calcium uptake and absorption from calcium-enriched gluten-free bread.

    Science.gov (United States)

    Krupa-Kozak, U; Swiątecka, D; Bączek, N; Brzóska, M M

    2016-04-20

    Compromised intestinal calcium absorption affecting a deterioration of bone state is a sign of coeliac disease. Experimental calcium-fortified gluten-free bread (GFB) of improved calcium bioavailability could increase calcium content in the diets of coeliac disease patients, allowing them to obtain the amount of calcium they need for therapeutic use. Prebiotics, including inulin-type fructans (IFs) have a beneficial effect on calcium bioavailability. In the present study, the in vitro model composed of the intestinal-like Caco-2 cells and the human intestinal bacteria (Lactobacillus, Enterococcus and Enterobacteriaceae) were used to analyse the effect of inulin and fructooligosaccharide (FOS) of different chain lengths, on calcium uptake and absorption from experimental GFB. Analysed IFs, especially short-chain FOS, significantly (p < 0.05) increased cellular calcium uptake from GFB digest and stimulated the intestinal bacteria applied in the cultures to the intensive synthesis of organic acids. In particular, the concentration of butyric, valeric and lactic acids increased significantly. Similarly, in the calcium absorption experiment, IFs increased the cellular calcium retention but concomitantly reduced its content in basolateral filtrates. The results obtained suggest that the applied IFs affected differentially calcium uptake and absorption from the experimental calcium-enriched GFB, therefore a further study is needed to assess whether these observations made in vitro contribute to IF effects on calcium absorption from experimental GFB in vivo. PMID:26965706

  8. Boron influences immune and antioxidant responses by modulating hepatic superoxide dismutase activity under calcium deficit abiotic stress in Wistar rats.

    Science.gov (United States)

    Bhasker, T Vijay; Gowda, N K S; Mondal, S; Krishnamoorthy, P; Pal, D T; Mor, A; Bhat, S Karthik; Pattanaik, A K

    2016-07-01

    The influence of Boron (B) supplementation on immune and antioxidant status of rats with or without abiotic stress induced by dietary calcium (Ca) restriction was studied in a feeding trial of 90 days. Wistar strain rats (3-4 wk age, n=84) were divided into 7 dietary groups (4 replicates of 3 each) viz., normal-calcium (100%) basal diet alone (NC, control) or supplemented with B at 5 (NCB-5), 10 (NCB-10), 20 (NCB-20) and 40ppm (NCB-40) levels; low-calcium (50%) basal diet alone (LC) or supplemented with 40ppm B (LCB-40). After 75 days of experimental feeding, rats were challenged with intraperitoneal injection of sheep RBCs to assess their humoral immunity. At the end of the trial, cell-mediated immunity was assessed as foot pad reaction to sheep RBCs injected into the hind leg paws. Eight rats from each group were sacrificed to collect blood for estimation of minerals and total antioxidant activity, and liver for superoxide dismutase gene expression analysis. Supplementation of graded levels of B (5, 10, 20 and 40ppm) as borax in NC diets significantly increased (Pcopper (Cu) and zinc (Zn) remained similar among the dietary groups, while the manganese (Mn) content was significantly decreased (P<0.01) with increased levels of dietary B. In conclusion, B supplementation increased the hepatic mRNA expression levels of both SOD isoenzymes, thereby improving the immune and antioxidant status. PMID:27259355

  9. Calcium Intake in Elderly Australian Women Is Inadequate

    Directory of Open Access Journals (Sweden)

    Colin W. Binns

    2010-09-01

    Full Text Available 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.

  10. Calcium phosphate mineralization is widely applied in crustacean mandibles

    OpenAIRE

    Shmuel Bentov; Aflalo, Eliahu D.; Jenny Tynyakov; Lilah Glazer; Amir Sagi

    2016-01-01

    Crustaceans, like most mineralized invertebrates, adopted calcium carbonate mineralization for bulk skeleton reinforcement. Here, we show that a major part of the crustacean class Malacostraca (which includes lobsters, crayfishes, prawns and shrimps) shifted toward the formation of calcium phosphate as the main mineral at specified locations of the mandibular teeth. In these structures, calcium phosphate is not merely co-precipitated with the bulk calcium carbonate but rather creates speciali...

  11. The stability mechanisms of an injectable calcium phosphate ceramic suspension.

    OpenAIRE

    Fatimi, Ahmed; Tassin, Jean-François; Axelos, Monique,; Weiss, Pierre

    2010-01-01

    International audience Calcium phosphate ceramics are widely used as bone substitutes in dentistry and orthopedic applications. For minimally invasive surgery an injectable calcium phosphate ceramic suspension (ICPCS) was developed. It consists in a biopolymer (hydroxypropylmethylcellulose: HPMC) as matrix and bioactive calcium phosphate ceramics (biphasic calcium phosphate: BCP) as fillers. The stability of the suspension is essential to this generation of "ready to use" injectable biomat...

  12. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    International Nuclear Information System (INIS)

    Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster, and for either homogeneous or heterogeneous coupled clusters, the synchronization of clusters, which is important to calcium signalling, is enhanced by the coupling effect

  13. Calcium Intake in Elderly Australian Women Is Inadequate

    OpenAIRE

    Colin W. Binns; Xingqiong Meng; Kerr, Deborah A; Kun Zhu; Amanda Devine; Vicky Solah; Richard L. Prince

    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...

  14. Beyond-root calcium fertilization of apple trees

    Directory of Open Access Journals (Sweden)

    Kazimierz Słowik

    2013-12-01

    Full Text Available Investigations were performed in the period 1977-1979 on the apple tree cultivar 'Fantazja', on rootstock A 2, M 7 and MM 106 on the effect of spraying with solution containing calcium on the incidence of bitter pit, breakdown, calcium content in the fruit flesh and other features of the fruits. Threefold spraying with calcium nitrate, calcium chloride or Anti-Stipp significantly limited the appearance of bitter pit and breakdown.

  15. Coupling Effect of Ion Channel Clusters on Calcium Signalling

    Institute of Scientific and Technical Information of China (English)

    TANG Jun; JIA Ya; YI Ming; MA Jun; YU Guang

    2008-01-01

    @@ Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters,the effects of coupling on calcium signalling are numerically investigated.The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster,and for either homogeneous or heterogeneous coupled clusters,the synchronization of clusters,which is important to calcium signalling,is enhanced by the coupling effect.

  16. Stability of calcium silicate in basic solution

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 李小斌; 彭志宏; 周秋生

    2003-01-01

    Mixture of CaO and SiO2 was sintered at 1 200 or 1 400 ℃ according to the mole ratio of CaO/SiO2 of 1 or 2, and then calcium silicate was leached in pure caustic or soda solution. The results indicated that calcium silicate exists much more stably in caustic solution than that in soda solution, and CaO*SiO2 is more stable than β-2CaO*SiO2 whether in caustic solution or in soda solution. The increase of sintering temperature favored the stability of calcium silicate in the leaching process. When β-2CaO*SiO2 was leached in soda solution, the increase of leaching temperature and time resulted in decomposing of more calcium silicate. And when β-2CaO*SiO2 was leached in caustic solution at high temperature, much 2CaO*SiO2*H2O but little CaO*SiO2*H2O appeared in slag.

  17. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

    2010-01-01

    )-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers...

  18. 21 CFR 184.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium hydroxide. 184.1205 Section 184.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS...

  19. Three-dimensionally Perforated Calcium Phosphate Ceramics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Porous calcium phosphate ceramics were produced by compression molding using a special mold followed by sintering. The porous calcium phosphate ceramics have three-dimensional and penetrated open pores380-400μm in diameter spaced at intervals of 200μm. The layers of the linear penetration pores alternately lay perpendicular to pore direction. The porosity was 59%-65% . The Ca/P molar ratios of the porous calcium phosphate ceramics range from 1.5 to 1.85. A binder containing methyl cellulose was most effective for preparing the powder compact among vinyl acetate, polyvinyl alcohol, starch, stearic acid, methyl cellulose and their mixtures. Stainless steel, polystyrene, nylon and bamboo were used as the long columnar male dies for the penetrated open pores. When polystyrene, nylon and bamboo were used as the long columnar male dies, the dies were burned out during the sintering process. Using stainless steel as the male dies with the removal of the dies before heat treatment resulted in a higher level of densification of the calcium phosphate ceramic.

  20. The rate of calcium turnover in bone

    International Nuclear Information System (INIS)

    This paper reports an analysis of the clearance of calcium-47 tracer from the plasma of human patients. Nine subjects have so far been analysed, and the results all deviate somewhat from those predicted from the conventional simple kinetic scheme. 3 figs

  1. Calcium flux assay in Xenopus oocytes.

    Science.gov (United States)

    Murphy, P M

    2001-05-01

    Many G protein-coupled receptors of interest to neuroscientists induce transient increases in [Ca(2+)](i), which can be used as a convenient measure of receptor activation in a variety of applications. This unit describes a simple calcium flux assay applied to Xenopus oocytes. PMID:18428482

  2. The Thermal Decomposition of Calcium Carbonate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The thermogravimetry(TG) and derivative thermogravimetry(DTG) curves of the thermal decomposition reaction of calcium carbonate have been measured at five different heating rates. The kinetic parameters and the reaction mechanism of the reaction were evaluated from analysis of the TG and DTG curves by using the Ozawa method, the combined integral and differential methods and the reduced equations derived by us.

  3. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking... agent in food in an amount not in excess of that reasonably required to produce its intended effect. (b... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food...

  4. 21 CFR 582.3189 - Calcium ascorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium ascorbate. 582.3189 Section 582.3189 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  5. 21 CFR 182.3189 - Calcium ascorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium ascorbate. 182.3189 Section 182.3189 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  6. 21 CFR 582.3225 - Calcium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sorbate. 582.3225 Section 582.3225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  7. 21 CFR 182.3225 - Calcium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sorbate. 182.3225 Section 182.3225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3225...

  8. 21 CFR 582.3221 - Calcium propionate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium propionate. 582.3221 Section 582.3221 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives §...

  9. 21 CFR 201.70 - Calcium labeling.

    Science.gov (United States)

    2010-04-01

    ... diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201.72(c) may be combined, if applicable, provided the ingredients are listed in alphabetical order, e.g., a calcium or sodium restricted diet. 1...

  10. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Science.gov (United States)

    2010-04-01

    ... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate... (racemic) form. (b) To assure safe use of the additive, the label and labeling of the food...

  11. Free-calcium distribution and calcium pulses in rat peripheral macrophages

    Science.gov (United States)

    Yu, Yanhua; Xing, Da; Tang, Yonghong; Jin, Ying

    2000-10-01

    With Laser Confocal Scanning Microscope (LCSM) system, three aspects of characteristics of free cytoplasmic calcium in rat peripheral macrophages are studied. One is the Ca2+ concentration in different area in the same cell. Second is the Ca2+ concentration in the same area in different dividing stage. Third is the feature of calcium pulses evoked by Kcl or pH changing. The results show that even in one cell, the evolution of the Ca2+ concentration is not the same in a different area. In the same area, the nucleolus Ca2+ concentration in division breaking stage is much higher than that in division stage. From the experiment phenomena, we conclude that Kcl itself can not evoke calcium pulses in the unexcitable macrophage, but the change of pH can trig calcium pulses in the same cells.

  12. Photodissociation studies of calcium-coronene and calcium-pyrene cation clusters

    Science.gov (United States)

    Scott, A. C.; Buchanan, J. W.; Flynn, N. D.; Duncan, M. A.

    2008-01-01

    Gas-phase cluster cations combining calcium atoms and the polycyclic aromatic hydrocarbons (PAHs) coronene (C24H12) and pyrene (C16H10) are produced in a molecular beam using laser vaporization in a pulsed nozzle cluster source. Time-of-flight mass spectrometry reveals the formation of clusters of the form Cax(coronene)y+ for up to x = 4 and y = 3 and Cax(pyrene)y+ for up to x = 2 and y = 3. Mass-selected photodissociation studies show that the calcium cation is the most prominent fragment for each system. Photoinduced calcium carbide formation is prominent when two or more calcium atoms are present. Additionally, there is evidence that these clusters can form sandwich structures.

  13. Mortar and concrete based on calcium sulphate binders

    NARCIS (Netherlands)

    Bakker, J.J.F.; Brouwers, H.J.H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For

  14. 21 CFR 182.2122 - Aluminum calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  15. 21 CFR 582.2122 - Aluminum calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent....

  16. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B;

    1996-01-01

    Indirect evidence supports a protective role of some EF-hand calcium-binding proteins against calcium-induced neurotoxicity. Little is known about how these proteins influence cytosolic calcium levels. After cloning the parvalbumin cDNA into an expression vector, teratocarcinoma cells (PCC7) were...

  17. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B;

    1996-01-01

    transfected. Parvalbumin-transfected and mock-transfected cells were loaded with the calcium indicator fura-2 and were exposed, in the same dish, to different concentrations of the calcium ionophore A23187 or to KCI. The results show that parvalbumin-transfected PCC7 cells had much better calcium buffering...

  18. 21 CFR 182.6215 - Monobasic calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Monobasic calcium phosphate. 182.6215 Section 182.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  19. 21 CFR 582.6215 - Monobasic calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Monobasic calcium phosphate. 582.6215 Section 582.6215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6215 Monobasic calcium phosphate. (a) Product. Monobasic calcium phosphate. (b) Conditions of use....

  20. Influence of the calcium sulfate source on the rheological behaviour of calcium sulfoaluminate cement pastes

    OpenAIRE

    Santacruz, Isabel; García-Maté, Marta; G. Aranda, Miguel Ángel; De la Torre, Ángeles G.

    2013-01-01

    Calcium sulfoaluminate (CSA) cements are receiving increasing attention since their manufacture produces much less CO2 than ordinary Portland cement (OPC) [1]. In addition, they show interesting properties such as high early-age strengths, short setting times and impermeability. The main uses of these CSA cements are for quick repairs and pre-cast products or floor concrete applications. They are prepared by mixing the clinker with different amounts of a calcium sulfate set regulator such as ...

  1. Hardening of calcium hydroxide and calcium silicate binders due to carbonation and hydration

    OpenAIRE

    Cizer, Özlem; Campforts, J; Balen, Koenraad Van; Elsen, Jan; Gemert, Dionys van

    2006-01-01

    Hardening of calcium hydroxide and calcium silicate binders composed of cement, rice husk ash (RHA) and lime in different compositions were studied with mechanical strength, mercury intrusion porosimetry, thermal analysis and SEM. When cement is partially replaced with RHA and lime, hardening occurs as a result of combined hydration, pozzolanic reaction and carbonation reaction. While hydration of cement contributes to the early strength development of the mortars, carbonation is much more pr...

  2. Degree of vinyl conversion in experimental amorphous calcium phosphate composites

    Science.gov (United States)

    Tarle, Z.; Knežević, A.; Matošević, D.; Škrtić, D.; Ristić, M.; Prskalo, K.; Musić, S.

    2009-04-01

    An experimental dental composite, based on amorphous calcium phosphate (ACP) with the potential to arrest caries development and regenerate mineral-deficient tooth structures has recently been developed. The aim of this study was to assess the degree of vinyl conversion (DVC) attained in experimental composites based on zirconia-modified ACP. Photo-activated resins were based on ethoxylated bisphenol A dimethacrylate (EBPADMA) [ETHM series with varying EBPADMA/triethylene glycol dimethacrylate (TEGDMA) molar ratios assigned 0.5-ETHM I, 0.85-ETHM II and 1.35-ETHM III], or 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]-propane (Bis-GMA) [BTHZ series]. To asses a possible effect of filler particle size on DVC, composites containing 60 mass % resin and 40 mass % of either milled ACP (mACP; median diameter d m = 0.9 μm) or coarse ACP (cACP; d m = 6.0 μm) were prepared, and irradiated with LED curing unit for 40 s. The DVC was calculated as the % change in the ratio of the integrated peak areas between the aliphatic and aromatic absorption bands determined by Fourier transform infrared spectroscopy (FTIR). The highest DVCs values were attained in mACP-BTHZ, cACP-BTHZ and mACP-ETHM III formulations. DVC of tested ACP composites (on average (76.76 ± 4.43)%) compares well with or exceeds DVCs values reported for the majority of commercial materials.

  3. A comparative study of calcium absorption following a single serving administration of calcium carbonate powder versus calcium citrate tablets in healthy premenopausal women

    Directory of Open Access Journals (Sweden)

    Haiyuan Wang

    2014-04-01

    Full Text Available Background: Calcium is an essential mineral often taken as a daily, long-term nutritional supplement. Data suggests that once-daily dosing is important with regard to long-term compliance of both drugs and nutritional supplements. Objective: This study was undertaken to compare the bioavailability of a single serving of two calcium supplements in healthy, premenopausal women. Design: A two-period, crossover bioavailability study of a single serving of calcium citrate tablets (two tablets=500 mg calcium versus a single serving of calcium carbonate powder (one packet of powder=1,000 mg calcium was performed in healthy women aged between 25 and 45. All subjects were on a calcium-restricted diet 7 days prior to testing and fasted for 12 h before being evaluated at 0, 1, 2, and 4 h after oral administration of the test agents. Blood measurements for total and ionized calcium and parathyroid hormone were performed and adverse events were monitored. Results: Twenty-three women were evaluable with a mean age of 33.2±8.71. Results showed that administration of a single serving of a calcium carbonate powder resulted in greater absorption in total and ionized calcium versus a single serving of calcium citrate tablets at 4 h (4.25±0.21 vs. 4.16±0.16, p=0.001. There were minimal side effects and no reported serious adverse events. Conclusions: This study shows that a single serving of a calcium carbonate powder is more bioavailable than a single serving of calcium citrate tablets. This may be beneficial for long-term compliance.

  4. Preparation and Characterization of Calcium Carbonate Nanoparticles

    Science.gov (United States)

    Hassim, Aqilah; Rachmawati, Heni

    2010-10-01

    Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In this study, we prepared and characterized calcium carbonate nanoparticle to improve the solubility by using bottom-up method. The experiment was done by titrating calcium chloride with sodium carbonate with the addition of polyvinylpyrrolidone (PVP) as stabilizer, using ultra-turrax. Various concentrations of calcium chloride and sodium carbonate as well as various speed of stirring were used to prepare the calcium carbonate nanoparticles. Evaluations studied were including particle size, polydispersity index (PI) and zeta potential with particle analyzer, surface morphology with scanning electron microscope, and saturated solubility. In addition, to test the ability of PVP to prevent particles growth, short stability study was performed by storing nano CaCO3 suspension at room temperature for 2 weeks. Results show that using 8000 rpm speed of stirring, the particle size tends to be bigger with the range of 500-600 nm (PI between 0.2-0.4) whereas with stirring speed of 4000 rpm, the particle size tends to be smaller with 300-400 nm (PI between 0.2-0.4). Stirring speed of 6000 rpm produced particle size within the range of 400-500 nm (PI between 0.2-0.4). SEM photograph shows that particles are monodisperse confirming that particles were physically stable without any agglomeration within 2 weeks storage. Taken together, nano CaCO3 is successfully prepared by bottom-up method and PVP is a good stabilizer to prevent the particle growth.

  5. Optogenetic measurement of presynaptic calcium transients using conditional genetically encoded calcium indicator expression in dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Carmelo Sgobio

    Full Text Available Calcium triggers dopamine release from presynaptic terminals of midbrain dopaminergic (mDA neurons in the striatum. However, calcium transients within mDA axons and axon terminals are difficult to study and little is known about how they are regulated. Here we use a newly-developed method to measure presynaptic calcium transients (PreCaTs in axons and terminals of mDA neurons with a genetically encoded calcium indicator (GECI GCaMP3 expressed in transgenic mice. Using a photomultiplier tube-based system, we measured electrical stimulation-induced PreCaTs of mDA neurons in dorsolateral striatum slices from these mice. Single-pulse stimulation produced a transient increase in fluorescence that was completely blocked by a combination of N- and P/Q-type calcium channel blockers. DA and cholinergic, but not serotoninergic, signaling pathways modulated the PreCaTs in mDA fibers. These findings reveal heretofore unexplored dynamic modulation of presynaptic calcium in nigrostriatal terminals.

  6. Calcium signaling and T-type calcium channels in cancer cell cycling

    Institute of Scientific and Technical Information of China (English)

    James T Taylor; Xiang-Bin Zeng; Jonathan E Pottle; Kevin Lee; Alun R Wang; Stephenie G Yi; Jennifer A S Scruggs; Suresh S Sikka; Ming Li

    2008-01-01

    Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells,free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear;however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.

  7. In vivo calcium imaging of evoked calcium waves in the embryonic cortex

    Directory of Open Access Journals (Sweden)

    Mikhail eYuryev

    2016-01-01

    Full Text Available The dynamics of intracellular calcium fluxes are instrumental in the proliferation, differentiation and migration of neuronal cells. Knowledge thus far of the relationship between these calcium changes and physiological processes in the developing brain has derived principally from ex vivo and in vitro experiments. Here, we present a new method to image intracellular calcium flux in the cerebral cortex of live rodent embryos, whilst attached to the dam through the umbilical cord. Using this approach we demonstrate induction of calcium waves by laser stimulation. These waves are sensitive to ATP-receptor blockade and are significantly increased by pharmacological facilitation of intracellular-calcium release. This approach is the closest to physiological conditions yet achieved for imaging of calcium in the embryonic brain and as such opens new avenues for the study of prenatal brain development. Furthermore, the developed method could open the possibilities of preclinical translational studies in embryos particularly important for developmentally related diseases such as schizophrenia and autism.

  8. Effect of three different calcium hydroxide mixtures (calcium hydroxide with glycerine, normal saline and distilled water) on root dentin microhardness

    OpenAIRE

    Hasheminia SM; Norouzynasab S

    2007-01-01

    Background and Aim: During root canal therapy, it is necessary to remove as many bacteria as possible from the root canal. The use of medicaments is recommended to reduce the microbial population prior to root filling. Calcium hydroxide pastes have been used because of their antibacterial effects and the ability of tissue dissolving. The aim of this study was to evaluate the effect of calcium hydroxide/glycerine mixture, calcium hydroxide/normal saline mixture and calcium hydroxide/distilled ...

  9. Calcium homeostasis in low and high calcium water acclimatized Oreochromis mossambicus exposed to ambient and dietary cadmium

    NARCIS (Netherlands)

    Pratap, H.B.; Wendelaar Bonga, S.E.

    2007-01-01

    The effects of cadmium administered via ambient water (10 mg/l) or food (10 mgCd/fish/day) on plasma calcium, corpuscles of Stannius and bony tissues of Oreochromis mossambicus acclimated to low calcium (0.2 mM) and high calcium (0.8 mM) water were studied for 2, 4, 14 and 35 days. In low calcium wa

  10. Effects of modulation of calcium levels and calcium fluxes on ABA- induced gene expression in barley aleurone

    NARCIS (Netherlands)

    Meulen, R.M. van der; Visser, K.; Wang, M.

    1996-01-01

    We present data to elucidate the involvement of calcium ions in abscisic acid (ABA)-induced gene expression. Modulation of external calcium concentrations was able to affect ABA-induced specific RAB gene expression. At a constant ABA level with increasing extracellular calcium level, an increasing R

  11. Continuous Modeling of Calcium Transport Through Biological Membranes

    Science.gov (United States)

    Jasielec, J. J.; Filipek, R.; Szyszkiewicz, K.; Sokalski, T.; Lewenstam, A.

    2016-08-01

    In this work an approach to the modeling of the biological membranes where a membrane is treated as a continuous medium is presented. The Nernst-Planck-Poisson model including Poisson equation for electric potential is used to describe transport of ions in the mitochondrial membrane—the interface which joins mitochondrial matrix with cellular cytosis. The transport of calcium ions is considered. Concentration of calcium inside the mitochondrion is not known accurately because different analytical methods give dramatically different results. We explain mathematically these differences assuming the complexing reaction inside mitochondrion and the existence of the calcium set-point (concentration of calcium in cytosis below which calcium stops entering the mitochondrion).

  12. Identification of quantitative trait loci controlling high Calcium response in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Wenlong Li

    Full Text Available Natural variation for primary root growth response to high Ca stress in Arabidopsis thaliana was studied by screening a series of accessions (ecotypes under high Calcium (40 mM CaCl2 conditions. The genetic basis of this variation was further investigated by QTL analysis using recombinant inbred lines from Landsberg erecta (Ler × Cape Verde Islands (Cvi cross. Four QTLs were identified in chromosome 1, 2 and 5,and named response to high Calcium (RHCA 1-4. The three QTLs (RHCA1, RHCA2 and RHCA4 were further confirmed by analysis of near isogenic lines harboring Cvi introgression fragments in Ler background. Real-time PCR analysis showed that several genes associated with high Ca response including SMT1 and XHT25 have changed expression pattern between Ler and near isogenic lines. These results were useful for detecting molecular mechanisms of plants for high Ca adaption.

  13. THE EFFECT OF PHOTOTHERAPY ON SERUM IONIZED CALCIUM LEVELS IN NEONATES WITH UNCONJUGATED HYPER BILIRUBINEMIA

    Directory of Open Access Journals (Sweden)

    Durga

    2015-04-01

    Full Text Available AIM : T o study the occurance of hypocalcemia in neonates with hyperbilirubinemia after 48 hours of continuous phototherapy and to compare the results between term and preterm neonates. METHODS : T his study was performed on 100 neonates with unconjugated hyper bilirubinemia , 55 term and 45 preterm , who were given photo phototherapy in neonatal intensive care unit . serum ionized calcium levels were checked and after 48 hours of phototherapy . The prevalence of hypo calcemia after 48 hrs. of phototherapy was observed and compared between full term and preterm neonates. Neonates who had hyperbilirubinemia , asphyxia , respiratory distress , haemolytic anaemia sepsis were excluded from the study . RESULTS: 46/100 NEONATES, THAT IS 46 % developed hypocalcemia. 22/55 full term neonates , that is 40% and 24/45 preterm neonates that is 53% developed hypocalcemia after 48 hrs. of phototherapy. CONCLUSION: significant decline in serum calcium level is observed in neonates receiving phototherapy for hyperbilirubinemia

  14. [Characteristics of calcium-phosphorus metabolism and vitamin D allowance in the Far North].

    Science.gov (United States)

    Blazheevich, N V; Spirichev, V B; Pereverzeva, O G; Tenditnaia, L V; Fanchenko, N D

    1983-01-01

    Examination of children aged 3 to 17 years and adult population including parturients living in Naryan-Mar and northern settlements of the Nenets national district revealed the reduced calcium and elevated phosphorus concentrations in the blood serum of the examinees as compared with respective parameters in analogous population groups living in the middle zone of Russia (Moscow and Kazan). These changes, particularly marked in winter and spring, are determined by national and local features of the diet poor in calcium and containing excess amount of phosphorus. The concentration of 25-hydroxyvitamin D in the blood serum of the population living in the Extreme North was 2 times lower than that in the population of the middle zone, constituting 15-20 and 30-40 ng/ml, respectively. The reason for a lower vitamin D supply in the North is insufficient insulation.

  15. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction. PMID:23827538

  16. A construction of novel iron-foam-based calcium phosphate/chitosan coating biodegradable scaffold material.

    Science.gov (United States)

    Wen, Zhaohui; Zhang, Liming; Chen, Chao; Liu, Yibo; Wu, Changjun; Dai, Changsong

    2013-04-01

    Slow corrosion rate and poor bioactivity restrict iron-based implants in biomedical application. In this study, we design a new iron-foam-based calcium phosphate/chitosan coating biodegradable composites offering a priority mechanical and bioactive property for bone tissue engineering through electrophoretic deposition (EPD) followed by a conversion process into a phosphate buffer solution (PBS). Tensile test results showed that the mechanical property of iron foam could be regulated through altering the construction of polyurethane foam. The priority coatings were deposited from 40% nano hydroxyapatite (nHA)/ethanol suspension mixed with 60% nHA/chitosan-acetic acid aqueous solution. In vitro immersion test showed that oxidation-iron foam as the matrix decreased the amount of iron implanted and had not influence on the bioactivity of this implant, obviously. So, this method could also be a promising method for the preparation of a new calcium phosphate/chitosan coating on foam construction.

  17. OSMOTIC DEHYDRATION KINETICS OF GUAVAS IN MALTOSE SOLUTIONS WITH CALCIUM SALT*

    Directory of Open Access Journals (Sweden)

    S. DI S. MASTRANTONIO

    2009-03-01

    Full Text Available

    The osmotic dehydration kinetics of guavas in maltose solutions at 40 and 60ºBrix, with addition of 0, 0.6 and 1.2% of calcium lactate was studied in this paper and the final product quality was evaluated. The experiments were carried out up to 60 hours and samples were taken for analysis at different times to evaluate guavas weight reduction, water loss and sugar gain and to characterize the product according to its texture and color. After 24 hours of process the mass transfer of water and sugar between the osmotic solution and the fruit was negligible, showing that process equilibrium was reached. The increase of sugar concentration in the osmotic solution showed strong influence on the dehydration process, increasing the water loss and reducing sugar gain. The presence of calcium ions in the osmotic solution also influenced the kinetics of mass transfer and showed a strong influence on fruit texture. Higher values of stress and strain at failure were obtained when calcium lactate was employed. The effect of the different osmotic treatments on the color parameters was also investigated and significant changes were observed in the values of chroma C* and hue H* due to sugar concentration and calcium addition.

    KEYWORDS: Osmotic dehydration; kinetics; guava; maltose; calcium lactate.

  18. Improvement of in vitro physicochemical properties and osteogenic activity of calcium sulfate cement for bone repair by dicalcium silicate

    International Nuclear Information System (INIS)

    Highlights: • Dicalcium silicate can improve osteogenic activity of calcium sulfate cement. • The higher the calcium sulfate content, the shorter the setting time in the composite cement. • The results were useful for designing calcium-based cement with optimal properties. -- Abstract: An ideal bone graft substitute should have the same speed of degradation as formation of new bone tissue. To improve the properties of calcium sulfate hemihydrate (CSH) featured for its rapid resorption, a low degradation material of dicalcium silicate (DCS) was added to the CSH cement. This study examined the effect of DCS (20, 40, 60 and 80 wt%) on the in vitro physicochemical properties and osteogenic activities of the calcium-based composite cements. The diametral tensile strength, porosity and weight loss of the composite cements were evaluated before and after soaking in a simulated body fluid (SBF). The osteogenic activities, such as proliferation, differentiation and mineralization, of human mesenchymal stem cells (hMSCs) seeded on cement surfaces were also examined. As a result, the greater the DCS amount, the higher the setting time was in the cement. Before soaking in SBF, the diametral tensile strength of the composite cements was decreased due to the introduction of DCS. On 180-day soaking, the composite cements containing 20, 40, 60 and 80 wt% DCS lost 80%, 69%, 61% and 44% in strength, respectively. Regarding in vitro bioactivity, the DCS-rich cements were covered with clusters of apatite spherulites after soaking for 7 days, while there was no formation of apatite spherulites on the CSH-rich cement surfaces. The presence of DCS could reduce the degradation of the CSH cements, as evidenced in the results of weight loss and porosity. More importantly, DCS may promote effectively the cell proliferation, proliferation and mineralization. The combination of osteogenesis of DCS and degradation of CSH made the calcium-based composite cements an attractive choice for

  19. Calcium-Mediated Abiotic Stress Signaling in Roots.

    Science.gov (United States)

    Wilkins, Katie A; Matthus, Elsa; Swarbreck, Stéphanie M; Davies, Julia M

    2016-01-01

    Roots are subjected to a range of abiotic stresses as they forage for water and nutrients. Cytosolic free calcium is a common second messenger in the signaling of abiotic stress. In addition, roots take up calcium both as a nutrient and to stimulate exocytosis in growth. For calcium to fulfill its multiple roles must require strict spatio-temporal regulation of its uptake and efflux across the plasma membrane, its buffering in the cytosol and its sequestration or release from internal stores. This prompts the question of how specificity of signaling output can be achieved against the background of calcium's other uses. Threats to agriculture such as salinity, water availability and hypoxia are signaled through calcium. Nutrient deficiency is also emerging as a stress that is signaled through cytosolic free calcium, with progress in potassium, nitrate and boron deficiency signaling now being made. Heavy metals have the capacity to trigger or modulate root calcium signaling depending on their dose and their capacity to catalyze production of hydroxyl radicals. Mechanical stress and cold stress can both trigger an increase in root cytosolic free calcium, with the possibility of membrane deformation playing a part in initiating the calcium signal. This review addresses progress in identifying the calcium transporting proteins (particularly channels such as annexins and cyclic nucleotide-gated channels) that effect stress-induced calcium increases in roots and explores links to reactive oxygen species, lipid signaling, and the unfolded protein response. PMID:27621742

  20. Consumption of calcium-fortified cereal bars to improve dietary calcium intake of healthy women: randomized controlled feasibility study.

    Directory of Open Access Journals (Sweden)

    Jennifer T Lee

    Full Text Available Calcium is an important structural component of the skeletal system. Although an adequate intake of calcium helps to maintain bone health and reduce the risk of osteoporosis, many women do not meet recommended daily intakes of calcium. Previous interventions studies designed to increase dietary intake of women have utilized primarily dairy sources of calcium or supplements. However, lactose intolerance, milk protein allergies, or food preferences may lead many women to exclude important dairy sources of dietary calcium. Therefore, we undertook a 9 week randomized crossover design trial to examine the potential benefit of including a non-dairy source of calcium in the diet of women. Following a 3 week run-in baseline period, 35 healthy women > 18 years were randomized by crossover design into either Group I or Group II. Group I added 2 calcium-fortified cereal bars daily (total of 400 mg calcium/day (intervention to their usual diet and Group II continued their usual diet (control. At the end of 3 weeks, diets were switched for another 3 weeks. Intakes of calcium and energy were estimated from 3-day diet and supplemental diaries. Wilcoxon signed-rank tests were used for within group comparisons and Mann Whitney U tests were used for between group comparisons of calcium and energy intake. Dietary calcium was significantly higher during intervention (1071 mg/d when participants consumed 2 calcium-fortified cereal bars daily than during the baseline (720 mg/d, P <0.0001 or control diets (775 mg/d, P = 0.0001 periods. Furthermore, the addition of 2 calcium-fortified cereal bars daily for the 3 week intervention did not significantly increase total energy intake or result in weight gain. In conclusion, consumption of calcium-fortified cereal bars significantly increased calcium intake of women. Further research examining the potential ability of fortified cereal bars to help maintain and improve bone health of women is warranted.ClinicalTrials.gov NCT

  1. Immobilization of calcium sulfate contained in demolition waste

    International Nuclear Information System (INIS)

    This paper presents the results of a laboratory study undertaken to examine the treatment of demolition waste containing calcium sulfate by means of calcium sulfoaluminate clinker (CSA). The quantity of CSA necessary to entirely consume calcium sulfate was determined. Using infrared spectrometry analysis and X-ray diffraction, it was shown that calcium sulfate was entirely consumed when the ratio between CSA and calcium sulfate was 4. Standard sand was polluted by 4% calcium sulfate. Two solutions were investigated: ·either global treatment of sand by CSA, ·or immobilization of calcium sulfate by CSA, followed by the introduction of this milled mixture in standard sand. Regardless of the type of treatment, swelling was almost stabilized after 28 days of immersion in water

  2. Calcium-dependent and calcium-sensitizing pathways in the mature and immature ductus arteriosus.

    Science.gov (United States)

    Clyman, Ronald I; Waleh, Nahid; Kajino, Hiroki; Roman, Christine; Mauray, Francoise

    2007-10-01

    Studies performed in sheep and baboons have shown that after birth, the normoxic muscle media of ductus arteriosus (DA) becomes profoundly hypoxic as it constricts and undergoes anatomic remodeling. We used isolated fetal lamb DA (pretreated with inhibitors of prostaglandin and nitric oxide production) to determine why the immature DA fails to remain tightly constricted during the hypoxic phase of remodeling. Under normoxic conditions, mature DA constricts to 70% of its maximal active tension (MAT). Half of its normoxic tension is due to Ca(2+) entry through calcium L-channels and store-operated calcium (SOC) channels. The other half is independent of extracellular Ca(2+) and is unaffected by inhibitors of sarcoplasmic reticulum (SR) Ca(2+) release (ryanodine) or reuptake [cyclopiazonic acid (CPA)]. The mature DA relaxes slightly during hypoxia (to 60% MAT) due to decreases in calcium L-channel-mediated Ca(2+) entry. Inhibitors of Rho kinase and tyrosine kinase inhibit both Ca(2+)-dependent and Ca(2+)-independent DA tension. Although Rho kinase activity may increase during gestation, immature DA develop lower tensions than mature DA, primarily because of differences in the way they process Ca(2+). Calcium L-channel expression increases with advancing gestation. Under normoxic conditions, differences in calcium L-channel-mediated Ca(2+) entry account for differences in tension between immature (60% MAT) and mature (70% MAT) DA. Under hypoxic conditions, differences in both calcium L-channel-dependent and calcium L-channel-independent Ca(2+) entry, account for differences in tension between immature (33% MAT) and mature (60% MAT) DA. Stimulation of Ca(2+) entry through reverse-mode Na(+)/Ca(2+) exchange or CPA-induced SOC channel activity constrict the DA and eliminate differences between immature and mature DA during both hypoxia and normoxia.

  3. Effectiveness of a theory-driven nutritional education program in improving calcium intake among older Mauritian adults.

    Science.gov (United States)

    Bhurosy, Trishnee; Jeewon, Rajesh

    2013-01-01

    Background. Low calcium intake, a risk factor of osteoporosis and subsequent fractures, has been previously reported among post-menopausal women in Mauritius. Objective. To assess the effectiveness of a theory-based educational intervention in improving the calcium intake, self-efficacy, and knowledge of older Mauritians. Methodology. The study was conducted as a pre- and post-test design which was evaluated through a baseline, immediate postintervention, and 2-month follow-up assessments. Participants were adults (n = 189) aged ≥40 years old from 2 urban community-based centres. The intervention group (IG) (n = 98) participated in 6 weekly interactive lessons based on the health belief model (HBM). The main outcome measures were calcium intake, HB scale scores, knowledge scores, and physical activity level (PAL). Anthropometric measurements were also assessed. Results. The IG significantly increased its baseline calcium intake, knowledge and self-efficacy (P educational intervention is effective in improving the dietary calcium intake, knowledge, self-efficacy, and PAL of older community-based Mauritian adults.

  4. Aggregation of Calcium Silicate Hydrate Nanoplatelets.

    Science.gov (United States)

    Delhorme, Maxime; Labbez, Christophe; Turesson, Martin; Lesniewska, Eric; Woodward, Cliff E; Jönsson, Bo

    2016-03-01

    We study the aggregation of calcium silicate hydrate nanoplatelets on a surface by means of Monte Carlo and molecular dynamics simulations at thermodynamic equilibrium. Calcium silicate hydrate (C-S-H) is the main component formed in cement and is responsible for the strength of the material. The hydrate is formed in early cement paste and grows to form platelets on the nanoscale, which aggregate either on dissolving cement particles or on auxiliary particles. The general result is that the experimentally observed variations in these dynamic processes generically called growth can be rationalized from interaction free energies, that is, from pure thermodynamic arguments. We further show that the surface charge density of the particles determines the aggregate structures formed by C-S-H and thus their growth modes. PMID:26859614

  5. Sensory analysis of calcium-biofortified lettuce.

    Science.gov (United States)

    Park, Sunghun; Elless, Mark P; Park, Jungeun; Jenkins, Alicia; Lim, Wansang; Chambers, Edgar; Hirschi, Kendal D

    2009-01-01

    Vegetables represent an attractive means of providing increased calcium nutrition to the public. In this study, it was demonstrated that lettuce expressing the deregulated Arabidopsis H(+)/Ca(2+) transporter sCAX1 (cation exchanger 1) contained 25%-32% more calcium than controls. These biofortified lettuce lines were fertile and demonstrated robust growth in glasshouse growth conditions. Using a panel of highly trained descriptive panellists, biofortified lettuce plants were evaluated and no significant differences were detected in flavour, bitterness or crispness when compared with controls. Sensory analysis studies are critical if claims are to be made regarding the efficacy of biofortified foods, and may be an important component in the public acceptance of genetically modified foods. PMID:19021875

  6. Electronic Structure of Gadolinium Calcium Oxoborate

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A; Adams, J; Schaffers, K

    2004-07-01

    Gadolinium calcium oxoborate (GdCOB) is a nonlinear optical material that belongs to the calcium--rare-earth (R) oxoborate family, with general composition Ca{sub 4}RO(BO{sub 3}){sub 3} (R{sup 3+} = La, Sm, Gd, Lu, Y). X-ray photoemission was applied to study the valence band electronic structure and surface chemistry of this material. High resolution photoemission measurements on the valence band electronic structure and Gd 3d and 4d, Ca 2p, B 1s and O 1s core lines were used to evaluate the surface and near surface chemistry. These results provide measurements of the valence band electronic structure and surface chemistry of this rare-earth oxoborate.

  7. Ceramics based on calcium pyrophosphate nanopowders

    Directory of Open Access Journals (Sweden)

    Tatiana V. Safronova

    2013-03-01

    Full Text Available Present work is aimed at the fabrication of resorbable bioceramics based on calcium pyrophosphate (CPP from the synthesized powders of amorphous hydrated calcium pyrophosphate (AHCPP. Amorphous hydratedcalcium pyrophosphate in the form of nanopowders was precipitated from Ca(NO3 2 and (NH4 4P2O7 solutions at room temperature in the presence of PO3– ions. Crystalline CPP powder was fabricated from AHCPP by its thermal decomposition at 600 °C and consisted of β- and α- phase. Small particles, with the size less than 200 nm, were formed promoting sintering of the ceramic material. The final sample, sintered at 900 °C, exhibits microstructure with submicron grains, apparent density of 87% of theoretical density (TD and demonstrates tensile strength of 70 MPa.

  8. Kinetics of Leaching Calcium from Dolomite

    Directory of Open Access Journals (Sweden)

    Azizi, A.

    2011-06-01

    Full Text Available Magnesia is obtained from magnesite ore and the production process applied should remove accompanying minerals that reduce its refractoriness. Given that magnesite reservoirs are more exploited and largely exhausted, there is a growing need for production of magnesia on the basis of other magnesium minerals. Dolomite is a promising source of magnesia because it forms large deposits, is easy to exploit, and generally contains a small quantity of impurities.The kinetics of calcium leaching from dolomite by magnesium-nitrate solution has been studied. The research program included the influence of temperature, mass fraction of magnesium nitrate in solution, dolomite particle size and leaching time. Time dependence of calcium leaching is described by relevant kinetic equations. Rate coefficients, their temperature dependence and Arrhenius activation energy have been determined.

  9. Characterization of ionomycin as a calcium ionophore.

    Science.gov (United States)

    Liu, C; Hermann, T E

    1978-09-10

    The ionophorous properties of a new antibiotic, ionomycin, have been studied. It was found that the antibiotic is capable of extracting calcium ion from the bulk of an aqueous phase into an organic phase. The antibiotic also acts as a mobile ion carrier to transport the cation across a solvent barrier. The divalent cation selectivity order for ionomycin as determined by ion competition experiments was found to be: Ca greater than Mg greater than Sr = Ba, where the binding of strontium and barium by the antibiotic is insignificant. The antibiotic also binds La3+ to some extent, but its complexation with monovalent alkali metal ions is negligible. Measurement of the binding of ionomycin with Ca2+ indicates that ionomycin complexes and transports calcium ion in a one to one stoichiometry. PMID:28319

  10. Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    GUO Xiu-lin; MA Yuan-yuan; LIU Zi-hui; LIU Bin-hui

    2008-01-01

    In this study, the direct effects of exterior abscisic acid (ABA) on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca2+ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), verapamil (Vp), and trifluoperazine (TFP). The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca2+ concentration of mesophyll cells was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 min after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca2+ concentration induced by ABA were involved in the stomatal movements of maize seedlings.

  11. Viscosity estimation for slags containing calcium fluoride

    Institute of Scientific and Technical Information of China (English)

    Qifeng Shu; Jiayun Zhang

    2005-01-01

    Based on recently published experimental data, the Riboud model was modified for viscosity estimation of the slags containing calcium fluoride. The estimated values were in good agreement with measured data. Reasonable estimation can be achieved using the modified Riboud model for mould fluxes and ESR (eletro slag remelting) slags. Especially for ESR slags, the modified Riboud model can provide much more precise values than the original Riboud model.

  12. Premixed calcium silicate cement for endodontic applications

    OpenAIRE

    Persson, Cecilia; Engqvist, Håkan

    2011-01-01

    Calcium silicate-based materials (also called MTA) are increasingly being used in endodontic applications. However, the handling properties of MTA are not optimal when it comes to injectability and cohesion. Premixing the cements using glycerol avoids these issues. However, there is a lack of data on the effect of common cement variables on important properties of premixed cements for endodontic applications. In this study, the effects of liquid-to-powder ratio, amount of radiopacifier and am...

  13. Coronary artery calcium scoring in myocardial infarction

    International Nuclear Information System (INIS)

    Background. The aim of this study was to evaluate coronary artery calcium scoring and the assessment of the risk factors in patients with myocardial infarction (MI). Methods. During the period of three years, 27 patients with MI were analyzed. The average age of patients was 66.1 years (46 to 81). Coronary arteries calcium was evaluated by multi row detector computed tomography (MTDC) Somatom Volume Zoom Siemens, and, retrospectively by ECG gating data acquisition. Semi automated calcium quantification to calculate Agatston calcium score (CS) was performed with 4 x 2.5 mm collimation, using 130 ml of contrast medium, injected with an automatic injector, with the flow rate of 4 ml/sec. The delay time was determined empirically. At the same time several risk factors were evaluated. Results. Out of 27 patients with MI, 3 (11.1%) patients had low CS (10- 100), 5 (18.5%) moderate CS (101- 499), and 19 (70.4%) patients high CS (>500). Of risk factors, smoking was confirmed in 17 (63.0%), high blood pressure (HTA) in 10 (57.0%), diabetes mellitus in 7 (25.9%), positive family history in 5 (18.5%), pathological lipids in 5 (18.5%), alcohol abuse in 4 (1.8%) patients. Six (22.2%) patients had symptoms of angina pectoris. Conclusions. The research showed high correlation of MI and high CS (>500). Smoking, HTA, diabetes mellitus, positive family history and hypercholesterolemia are significant risk factors. Symptoms are relatively poor in large number of patients. (author)

  14. Calcium metabolism in lithium-treated patients

    International Nuclear Information System (INIS)

    The bone mineral content (BMC) together with biochemical indices of calcium metabolism were measured in 83 manic-depressive patients on long-term lithium therapy. The patients were diagnosed and divided into a unipolar and a bipolar group according to strict symptomatic course criteria. The patients with bipolar course had a significantly decreased BMC (88% of normal, P < 0.001), while the unipolar patients had normal BMC. Both groups had biochemical changes consistent with primary hyperparathyroidism. (author)

  15. Bone disease in calcium stone forming patients.

    Science.gov (United States)

    Heilberg, I P; Martini, L A; Szejnfeld, V L; Carvalho, A B; Draibe, S A; Ajzen, H; Ramos, O L; Schor, N

    1994-09-01

    The association between idiopathic hypercalciuria and osteopenia (OP) has been recently recognized. It is not established whether or not calcium intake plays a critical role in the loss of bone mass. Fifty-five calcium stone forming patients with either absorptive hypercalciuria (AH) or fasting hypercalciuria (FH), 29 males and 26 premenopausal females, were submitted to dual photon absorptiometry at lumbar spine. Calcium intake was assessed by a 72 hr dietary record. OP was detected in 20% (11/55) of patients, being more common among men, 9/26 (35%) than in women, 2/29 (7%), p < 0.05. Male FH patients presented lower mean bone mineral density (BMD) than sex, weight and age-matched control (1.058 +/- 0.18 vs 1.209 +/- 0.13 g/cm2, X +/- SD, p < 0.05). OP was more frequent in FH patients, 7/20 (35%) than in AH patients 4/35 (11%), albeit the difference was not statistically significant. There was no correlation between calcium intake and BMD measurement. Six osteopenic male FH patients were further submitted to histomorphometric evaluation with tetracycline double labeling. Bone volume was lower than the controls (13.2 +/- 3.0 vs 27.2 +/- 3.7%, p < 0.05). Osteoid surfaces were reduced, although not significantly (10.1 +/- 8.2% vs 15.9 +/- 6.7%). Eroded surfaces were markedly increased (23.9 +/- 13.4 vs 4.2 +/- 1.4%, p < 0.05). The bone formation rate was very low with a complete lack of tetracycline double labeling in 4 patients. These data suggest low bone volume, tendency to low bone formation, increased bone resorption and a severe mineralization defect, consistent with normal or low bone turnover osteoporosis. PMID:7994936

  16. Gel time of calcium acrylate grouting material

    Institute of Scientific and Technical Information of China (English)

    韩同春

    2004-01-01

    Calcium acrylate is a polymerized grout, and can polymerize in an aqueous solution. The polymerizationreaction utilizes ammonium persulfate as a catalyst and sodium thiosulfate as the activator. Based on the theory of reactionkinetics, this study on the relation between gel time and concentration of activator and catalyst showed that gel time ofcalcium acrylate is inversely proportional to activator and catalyst concentration. A formula of gel time is proposed, and anexample is provided to verify the proposed formula.

  17. Biomimetic mineralization: encapsulation in calcium carbonate shells

    OpenAIRE

    Oliveira, Susana Costa de

    2015-01-01

    Calcium carbonate biomineralization is a self-assembly process that has been studied to be applied in the biomedical field to encapsulate biomolecules. Advantages of engineering mineral capsules include improved drug loading efficiencies and protection against external environment. However, common production methods result in heterogeneous capsules and subject biomolecules to heat and vibration which cause irreversible damage. To overcome these issues, a microfluidic device was designed, m...

  18. Recording of calcium transient and analysis of calcium removal mechanisms in cardiac myocytes from rats and ground squirrels

    Institute of Scientific and Technical Information of China (English)

    王世强; 周曾铨; 钱洪

    2000-01-01

    With confocal microscopy, we recorded calcium transients and analyzed calcium removal rate at different temperatures in cardiac myocytes from the rat, a non-hibernator, and the ground squirrel, a hibernator. The results showed a remarkable increase of the diastolic level of calcium transients in the rat but no detectable change in the ground squirrel. Calcium transient of the ground squirrel, compared with that of the rat at the same temperature, had a shorter duration and showed a faster calcium removal. As indicated by the pharmacological effect of cyclopiazonic acid, calcium uptake by sarcoplasmic reticulum (SR) was the major mechanism of calcium removal, and was faster in the ground squirrel than in the rat. Our results confirmed the essential role of SR in hypothermia-tolerant adaptation, and negated the importance of Na-Ca exchange. We postulated the possibility to improve hypothermia-tolerance of the cardiac tissue of non-hibernating mammals.

  19. T-Type Calcium Channel: A Privileged Gate for Calcium Entry and Control of Adrenal Steroidogenesis.

    Science.gov (United States)

    Rossier, Michel F

    2016-01-01

    Intracellular calcium plays a crucial role in modulating a variety of functions such as muscle contraction, hormone secretion, gene expression, or cell growth. Calcium signaling has been however shown to be more complex than initially thought. Indeed, it is confined within cell microdomains, and different calcium channels are associated with different functions, as shown by various channelopathies. Sporadic mutations on voltage-operated L-type calcium channels in adrenal glomerulosa cells have been shown recently to be the second most prevalent genetic abnormalities present in human aldosterone-producing adenoma. The observed modification of the threshold of activation of the mutated channels not only provides an explanation for this gain of function but also reminds us on the importance of maintaining adequate electrophysiological characteristics to make channels able to exert specific cellular functions. Indeed, the contribution to steroid production of the various calcium channels expressed in adrenocortical cells is not equal, and the reason has been investigated for a long time. Given the very negative resting potential of these cells, and the small membrane depolarization induced by their physiological agonists, low threshold T-type calcium channels are particularly well suited for responding under these conditions and conveying calcium into the cell, at the right place for controlling steroidogenesis. In contrast, high threshold L-type channels are normally activated by much stronger cell depolarizations. The fact that dihydropyridine calcium antagonists, specific for L-type channels, are poorly efficient for reducing aldosterone secretion either in vivo or in vitro, strongly supports the view that these two types of channels differently affect steroid biosynthesis. Whether a similar analysis is transposable to fasciculata cells and cortisol secretion is one of the questions addressed in the present review. No similar mutations on L-type or T-type channels

  20. T-type calcium channel: a privileged gate for calcium entry and control of adrenal steroidogenesis

    Directory of Open Access Journals (Sweden)

    Michel Florian Rossier

    2016-05-01

    Full Text Available Intracellular calcium plays a crucial role in modulating a variety of functions such as muscle contraction, hormone secretion, gene expression or cell growth. Calcium signaling has been however shown to be more complex than initially thought. Indeed, it is confined within cell microdomains and different calcium channels are associated with different functions, as shown by various channelopathies.Sporadic mutations on voltage-operated L-type calcium channels in adrenal glomerulosa cells have been shown recently to be the second most prevalent genetic abnormalities present in human aldosterone-producing adenoma. The observed modification of the threshold of activation of the mutated channels not only provides an explanation for this gain of function but reminds us on the importance of maintaining adequate electrophysiological characteristics to make channels able to exert specific cellular functions. Indeed, the contribution to steroid production of the various calcium channels expressed in adrenocortical cells is not equal and the reason has been investigated for a long time. Given the very negative resting potential of these cells, and the small membrane depolarization induced by their physiological agonists, low threshold T-type calcium channels are particularly well suited for responding under these conditions and conveying calcium into the cell, at the right place for controlling steroidogenesis. In contrast, high threshold L-type channels are normally activated by much stronger cell depolarizations. The fact that dihydropyridine calcium antagonists, specific for L-type channels, are poorly efficient for reducing aldosterone secretion either in vivo or in vitro, strongly supports the view that these two types of channels differently affect steroid biosynthesis.Whether a similar analysis is transposable to fasciculata cells and cortisol secretion is one of the questions addressed in the present review. No similar mutations on L-type or T

  1. Calcium and ROS: A mutual interplay.

    Science.gov (United States)

    Görlach, Agnes; Bertram, Katharina; Hudecova, Sona; Krizanova, Olga

    2015-12-01

    Calcium is an important second messenger involved in intra- and extracellular signaling cascades and plays an essential role in cell life and death decisions. The Ca(2+) signaling network works in many different ways to regulate cellular processes that function over a wide dynamic range due to the action of buffers, pumps and exchangers on the plasma membrane as well as in internal stores. Calcium signaling pathways interact with other cellular signaling systems such as reactive oxygen species (ROS). Although initially considered to be potentially detrimental byproducts of aerobic metabolism, it is now clear that ROS generated in sub-toxic levels by different intracellular systems act as signaling molecules involved in various cellular processes including growth and cell death. Increasing evidence suggests a mutual interplay between calcium and ROS signaling systems which seems to have important implications for fine tuning cellular signaling networks. However, dysfunction in either of the systems might affect the other system thus potentiating harmful effects which might contribute to the pathogenesis of various disorders. PMID:26296072

  2. Collective Calcium Signaling of Defective Multicellular Networks

    Science.gov (United States)

    Potter, Garrett; Sun, Bo

    2015-03-01

    A communicating multicellular network processes environmental cues into collective cellular dynamics. We have previously demonstrated that, when excited by extracellular ATP, fibroblast monolayers generate correlated calcium dynamics modulated by both the stimuli and gap junction communication between the cells. However, just as a well-connected neural network may be compromised by abnormal neurons, a tissue monolayer can also be defective with cancer cells, which typically have down regulated gap junctions. To understand the collective cellular dynamics in a defective multicellular network we have studied the calcium signaling of co-cultured breast cancer cells and fibroblast cells in various concentrations of ATP delivered through microfluidic devices. Our results demonstrate that cancer cells respond faster, generate singular spikes, and are more synchronous across all stimuli concentrations. Additionally, fibroblast cells exhibit persistent calcium oscillations that increase in regularity with greater stimuli. To interpret these results we quantitatively analyzed the immunostaining of purigenic receptors and gap junction channels. The results confirm our hypothesis that collective dynamics are mainly determined by the availability of gap junction communications.

  3. Fractional Dynamics in Calcium Oscillation Model

    Directory of Open Access Journals (Sweden)

    Yoothana Suansook

    2015-01-01

    Full Text Available The calcium oscillations have many important roles to perform many specific functions ranging from fertilization to cell death. The oscillation mechanisms have been observed in many cell types including cardiac cells, oocytes, and hepatocytes. There are many mathematical models proposed to describe the oscillatory changes of cytosolic calcium concentration in cytosol. Many experiments were observed in various kinds of living cells. Most of the experimental data show simple periodic oscillations. In certain type of cell, there exists the complex periodic bursting behavior. In this paper, we have studied further the fractional chaotic behavior in calcium oscillations model based on experimental study of hepatocytes proposed by Kummer et al. Our aim is to explore fractional-order chaotic pattern in this oscillation model. Numerical calculation of bifurcation parameters is carried out using modified trapezoidal rule for fractional integral. Fractional-order phase space and time series at fractional order are present. Numerical results are characterizing the dynamical behavior at different fractional order. Chaotic behavior of the model can be analyzed from the bifurcation pattern.

  4. Mitochondrial calcium uptake capacity modulates neocortical excitability.

    Science.gov (United States)

    Sanganahalli, Basavaraju G; Herman, Peter; Hyder, Fahmeed; Kannurpatti, Sridhar S

    2013-07-01

    Local calcium (Ca(2+)) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca(2+) uptake. Mitochondria take up Ca(2+) through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca(2+). Known only in vitro, the in vivo impact of mCU activity may reveal Ca(2+)-mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca(2+) sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca(2+) distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca(2+)-dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca(2+) uptake-mediated integrative role of in vivo mitochondria on neocortical activity.

  5. Arterial Stiffness and Dialysis Calcium Concentration

    Directory of Open Access Journals (Sweden)

    Fabrice Mac-Way

    2011-01-01

    Full Text Available Arterial stiffness is the major determinant of isolated systolic hypertension and increased pulse pressure. Aortic stiffness is also associated with increased cardiovascular morbidity and mortality in patients with chronic kidney disease, hypertension, and general population. Hemodynamically, arterial stiffness results in earlier aortic pulse wave reflection leading to increased cardiac workload and decreased myocardial perfusion. Although the clinical consequence of aortic stiffness has been clearly established, its pathophysiology in various clinical conditions still remains poorly understood. The aim of the present paper is to review the studies that have looked at the impact of dialysis calcium concentration on arterial stiffness. Overall, the results of small short-term studies suggest that higher dialysis calcium is associated with a transient but significant increase in arterial stiffness. This calcium dependant increase in arterial stiffness is potentially explained by increased vascular smooth muscle tone of the conduit arteries and is not solely explained by changes in mean blood pressure. However, the optimal DCa remains to be determined, and long term studies are required to evaluate its impact on the progression of arterial stiffness.

  6. Modeling Calcium Wave Based on Anomalous Subdiffusion of Calcium Sparks in Cardiac Myocytes

    Science.gov (United States)

    Chen, Xi; Kang, Jianhong; Fu, Ceji; Tan, Wenchang

    2013-01-01

    sparks and waves play important roles in calcium release and calcium propagation during the excitation-contraction (EC) coupling process in cardiac myocytes. Although the classical Fick’s law is widely used to model sparks and waves in cardiac myocytes, it fails to reasonably explain the full-width at half maximum(FWHM) paradox. However, the anomalous subdiffusion model successfully reproduces sparks of experimental results. In this paper, in the light of anomalous subdiffusion of sparks, we develop a mathematical model of calcium wave in cardiac myocytes by using stochastic release of release units (CRUs). Our model successfully reproduces calcium waves with physiological parameters. The results reveal how concentration waves propagate from an initial firing of one CRU at a corner or in the middle of considered region, answer how large in magnitude of an anomalous spark can induce a wave. With physiological currents (2pA) through CRUs, it is shown that an initial firing of four adjacent CRUs can form a wave. Furthermore, the phenomenon of calcium waves collision is also investigated. PMID:23483894

  7. 40 CFR 415.32 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Science.gov (United States)

    2010-07-01

    ... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.32 Effluent limitations guidelines... technology currently available (BPT). Except as provided in 40 CFR 125.30 through 125.32, any existing...

  8. Simulation of calcium oxalate stone in vitro

    Institute of Scientific and Technical Information of China (English)

    欧阳健明; 姚秀琼; 苏泽轩; 崔福斋

    2003-01-01

    Crystallization of calcium oxalate is studied mainly in the diluted healthy urine using scanning electron microscopy (SEM), and is compared with the crystallization in the diluted pathological urine. It suggests that the average sizes of calcium oxalate crystals are not in direct proportion to the concentrations of Ca2+ and Ox2- ions. Only in the concentration range of 0.60-0.90 mmol/L can larger size of CaOx crystals appear. When the concentrations of Ca2+ and Ox2- ions are 1.20, 0.80, 0.60, 0.30 and 0.15 mmol/L in the healthy urine, the average sizes of calcium oxalate crystallites are 9.5 × 6.5, 20.0 × 13.5 and 15.0 μm × 10.0 μm, respectively, for the former three samples after 6 d crystallization. No crystal appears even after 30 d crystallization for the samples of concentrations of 0.30 and 0.15 mmol/L due to their low supersaturations. The results theoretically explain why the probability of stone forming is clinically not in direct proportion to the concentrations of Ca 2+ and Ox2- ions. Laser scattering technology also confirms this point. The reason why healthy human has no risk of urinary stone but stone-formers have is that there are more urinary macromolecules in healthy human urines than that in stone-forming urines. These macromolecules may control the transformation in CaOx crystal structure from monohydrate calcium oxalate (COM) to dihydrate calcium oxalate (COD). COD has a weaker affinity for renal tubule cell membranes than COM. No remarkable effect of the crystallization time is observed on the crystal morphology of CaOx. All the crystals are obtuse hexagon. However, the sizes and the number of CaOx crystals can be affected by the crystallization time. In the early stage of crystallization (1-6 d), the sizes of CaOx crystals increase and the number of crystal particles changes little as increasing the crystallization time due to growth control. In the middle and late stages (6-30 d), the number of crystals increases markedly while the

  9. Effect of calcium on moving-bed biofilm reactor biofilms.

    Science.gov (United States)

    Goode, C; Allen, D G

    2011-03-01

    The effect of calcium concentration on the biofilm structure, microbiology, and treatment performance was evaluated in a moving-bed biofilm reactor. Three experiments were conducted in replicate laboratory-scale reactors to determine if wastewater calcium is an important variable for the design and optimization of these reactors. Biofilm structural properties, such as thickness, oxygen microprofiles, and the composition of extracellular polymeric substances (EPS) were affected by increasing calcium concentrations. Above a threshold concentration of calcium between 1 and 50 mg/L, biofilms became thicker and denser, with a shift toward increasingly proteinaceous EPS at higher calcium concentrations up to 200 mgCa2+/L. At 300 mgCa2+/L, biofilms were found to become primarily composed of inorganic calcium precipitates. Microbiology was assessed through microscopy, denaturing grade gel electrophoresis, and enumeration of higher organisms. Higher calcium concentrations were found to change the bacterial community and promote the abundant growth of filamentous organisms and various protazoa and metazoan populations. The chemical oxygen demand removal efficiency was improved for reactors at calcium concentrations of 50 mg/L and above. Reactor effluents for the lowest calcium concentration (1 mgCa2+/L) were found to be turbid (>50 NTU), as a result of the detachment of small and poorly settling planktonic biomass, whereas higher concentrations promoted settling of the suspended phase. In general, calcium was found to be an important variable causing significant changes in biofilm structure and reactor function.

  10. Calcium and iron absorption: mechanism of action and nutritional importance.

    Science.gov (United States)

    Hallberg, L; Rossander-Hultén, L; Brune, M; Gleerup, A

    1992-05-01

    We investigated the inhibitory effect of calcium on iron absorption in 57 human subjects. Three studies suggested that the effect is not located in the gastrointestinal tract. The presence of phytate in a meal and formation of calcium-iron-phytate complexes is not a prerequisite for the inhibition. The relative increase in iron absorption by ascorbic acid was the same in meals with and without calcium, suggesting that calcium did not influence the balance between enhancing and inhibiting ligands in the gastrointestinal lumen. No inhibiting effect on iron absorption was seen when adding 3 mg calcium to 0.01 mg iron (molar ratio Ca/Fe = 420). Previous studies showing a marked inhibition by calcium had a lower molar ratio, but greater amounts of calcium were given. This suggests that a minimal concentration of calcium is needed to achieve an effect. The present results indirectly support our original hypothesis that the inhibitory effect of calcium on iron absorption is situated within the intestinal mucosal cells. The practical nutritional implications of the inhibitory effect of calcium are considerable since addition of milk, milkshake or cheese to common meals such as pizza or hamburger meals reduced iron absorption by 50-60%. It is recommended to reduce the intake of dairy products with the main meals providing most of the dietary iron, especially for those having the highest iron requirements i.e. children, teenagers and women at childbearing age. PMID:1600930

  11. Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

    OpenAIRE

    Punit Fulzele; Sudhindra Baliga; Nilima Thosar; Debaprya Pradhan

    2011-01-01

    Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized wat...

  12. Homer regulates calcium signalling in growth cone turning

    Directory of Open Access Journals (Sweden)

    Thompson Michael JW

    2009-08-01

    Full Text Available Abstract Background Homer proteins are post-synaptic density proteins with known functions in receptor trafficking and calcium homeostasis. While they are key mediators of synaptic plasticity, they are also known to function in axon guidance, albeit by mechanisms that are yet to be elucidated. Homer proteins couple extracellular receptors – such as metabotropic glutamate receptors and the transient receptor potential canonical family of cation channels – to intracellular receptors such as inositol triphosphate and ryanodine receptors on intracellular calcium stores and, therefore, are well placed to regulate calcium dynamics within the neural growth cone. Here we used growth cones from dorsal root ganglia, a well established model in the field of axon guidance, and a growth cone turning assay to examine Homer1 function in axon guidance. Results Homer1 knockdown reversed growth cone turning from attraction to repulsion in response to the calcium-dependent guidance cues brain derived neurotrophic factor and netrin-1. Conversely, Homer1 knockdown had no effect on repulsion to the calcium-independent guidance cue Semaphorin-3A. This reversal of attractive turning suggested a requirement for Homer1 in a molecular switch. Pharmacological experiments confirmed that the operational state of a calcium-calmodulin dependent protein kinase II/calcineurin phosphatase molecular switch was dependent on Homer1 expression. Calcium imaging of motile growth cones revealed that Homer1 is required for guidance-cue-induced rise of cytosolic calcium and the attenuation of spontaneous cytosolic calcium transients. Homer1 knockdown-induced calcium transients and turning were inhibited by antagonists of store-operated channels. In addition, immunocytochemistry revealed the close association of Homer1 with the store-operated proteins TRPC1 and STIM1 within dorsal root ganglia growth cones. Conclusion These experiments provide evidence that Homer1 is an essential

  13. Synthesis of Calcium Silicate (Casio3 Using Calcium Fluoride, Quartz and Microbes

    Directory of Open Access Journals (Sweden)

    B. Gopal Krishna

    2015-09-01

    Full Text Available Microbes like bacteria, algae, fungi and virus play an important role to catalyst chemical reactions. In Nature, ores or minerals of different compounds are formed due to microbial environment and other factors like weathering. Microbial environment is also instrumental in forming calcium containing silicate minerals. Chemical reactions occur under microbial environment because microbes have the ability to control or modify different factors like pH, chemical potential and temperature during reactions. In this paper, synthesis of calcium silicate (CaSiO3 using calcium fluoride (CaF2 and quartz (SiO2 under microbial environment in a laboratory is being adopted to produce the required material. XRD technique is used to confirm the formation of CaSiO3.

  14. Assembly and Calcium Binding Properties of Quantum Dot-Calmodulin Calcium Sensor.

    Science.gov (United States)

    Eun, Su-yong; Nguyen-ta, Kim; Yoo, Hoon; Silva, Gabriel A; Kim, Soon-jong

    2016-02-01

    We have developed the first nanoengineered quantum dot molecular complex designed to measure changes of calcium ion (Ca2+) concentration at high spatial and temporal resolutions in real time. The sensor is ratiometric and composed of three components: a quantum dot (QD) emitting at 620 nm as a fluorescence donor, an organic dye (Alexa Fluor 647) as a fluorescence acceptor, and a calmodulin-M13 (CaM-M13) protein part as a calcium sensing component. In this work, we have determined the maximal number of CaM-M13 required for saturating a single QD particle to be approximately 16. The dissociation constant, Kd of the QD-based calcium ion sensor was also estimated to be around 30 microM. PMID:27433729

  15. Nuclear symmetry energy in calcium-calcium collisions (INDRA-VAMOS

    Directory of Open Access Journals (Sweden)

    Chartier M.

    2012-07-01

    Full Text Available The density dependence of the symmetry energy is of great interest to many fields of nuclear physics and nuclear astro-physics. The E503 INDRA-VAMOS experiment performed at GANIL in 2007 is intended to provide further sub-saturation constraints using calcium-calcium collisions around the Fermi energy (35AMeV. In these proceedings this experiment will be discussed in the context of the physics it is aiming to study and will give a brief summary of the current progress of the data analysis.

  16. Precipitation of calcium carbonate from a calcium acetate and ammonium carbamate batch system

    Science.gov (United States)

    Prah, J.; Maček, J.; Dražič, G.

    2011-06-01

    In this paper, we report a novel approach for preparing precipitated calcium carbonate using solutions of ammonium carbamate and calcium acetate as the sources of calcium and carbon dioxide, respectively. Two different concentrations of the starting solutions at three different temperatures (15, 25 and 50 °C) were used for the reaction. The influence of temperature and concentration on the polymorphism and the resulting morphology of calcium carbonate are discussed. The most important parameter for controlling a particular crystal structure and precipitate morphology were the concentrations of the initial solutions. When initial solutions with lower concentrations were used, the crystal form of the precipitate changed with time. Regardless the different polymorphism at different temperatures, after one day only the calcite form was detected in all samples, regardless of at which temperature the samples were prepared. At higher concentrations, pure vaterite or a mixture of vaterite and calcite were present at the beginning of the experiment. After one day, pure vaterite was found in the samples that were prepared at 15 and 25 °C. If calcium carbonate precipitated at 50 °C, the XRD results showed a mixture of calcite and vaterite regardless of the time at which the sample was taken. The morphology of calcium carbonate particles prepared at various conditions changed from calcite cubes to spherical particles of vaterite and aragonite needles. When a low starting concentration was used, the morphology at the initial stage was strongly affected by the temperature at which the experiments were conducted. However, after one day only, cubes were present in all cases at low initial concentrations. In contrast, at high concentrations spherical particles precipitated at all three temperatures at the beginning of the reaction. Spherical particles were made up from smaller particles. Over time, the size of the particles was diminishing due to their disintegration into

  17. Construction of calcium release sites in cardiac myocytes

    Directory of Open Access Journals (Sweden)

    Alexandra eZahradnikova

    2012-08-01

    Full Text Available Local character of calcium release in cardiac myocytes, as defined by confocal recordings of calcium sparks, implies independent activation of individual calcium release sites based on ryanodine receptor (RyR channel recruitment. We constructed virtual calcium release sites (vCRSs composed of a variable number of RyR channels distributed in clusters in accordance with the experimentally observed cluster size distribution. The vCRSs consisted either of a single virtual calcium release unit, in which all clusters shared a common dyadic space, or of multiple virtual calcium release units containing one cluster each and having separate dyadic spaces. We explored the stochastic behavior of vCRSs to understand the activation and recruitment of RyRs during calcium sparks. RyRs were represented by the published allosteric gating model that included regulation by cytosolic Ca2+ and Mg2+. The interaction of Mg2+ with the RyR Ca2+-binding sites and the refractory period of vCRSs were optimized to accord with the experimentally observed calcium dependence of calcium spark frequency. The Mg2+-binding parameters of RyRs that provided the best description of spark frequency depended on the number of RyRs assembled in the virtual calcium release sites. Adequate inhibitory effect of Mg2+ on the calcium dependence of RyR open probability was achieved if the virtual calcium release sites contained at least three clusters. For the distribution of the number of open RyRs in evoked calcium sparks to correspond to the experimentally observed distribution of spark calcium release fluxes, at least 3 clusters had to share a common virtual calcium release unit, in which ~ 3 RyRs open to form an average spark. These results reconcile the small cluster size and stochastic placement of RyRs in the release sites with the estimates of the amount of RyR protein, volume density of calcium release sites, and the size of calcium release sites in rat cardiac myocytes.

  18. Yeast respond to hypotonic shock with a calcium pulse

    Science.gov (United States)

    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.

  19. Adaptative diversity of calcium metabolism in gammarus fossarum populations

    Energy Technology Data Exchange (ETDEWEB)

    Meyran, J.C. [Grenoble-1 Univ., 38 (France)

    1994-11-01

    Analysis of Gammarus fossarum populations from mountain torrents in the Grenoble region reveals some morphological and eco physiological diversity which appears to be related to the calcium concentration of the water after both field and laboratory experimentation. Animals from waters with a high calcium concentration (located in Chartreuse and Vercors) show larger size and a longer molt cycle than those from low calcium concentrated waters (located in Belledonne); their calcium balance during the molt cycle is different. Translocation experiments confirm these differences: a significant increase of the duration of the molt cycle is observed in animals translocated to lower calcium concentrated waters and vice-versa whereas no significant difference is observed between controls and animals translocated within comparably calcium concentrated waters. The causes of such an adaptative diversity between Gammarus fossarum populations will be researched at the genetic level, namely through mitochondrial DNA investigations. (author). 25 refs., 2 tabs., 2 figs.

  20. Adaptative diversity of calcium metabolism in gammarus fossarum populations

    International Nuclear Information System (INIS)

    Analysis of Gammarus fossarum populations from mountain torrents in the Grenoble region reveals some morphological and eco physiological diversity which appears to be related to the calcium concentration of the water after both field and laboratory experimentation. Animals from waters with a high calcium concentration (located in Chartreuse and Vercors) show larger size and a longer molt cycle than those from low calcium concentrated waters (located in Belledonne); their calcium balance during the molt cycle is different. Translocation experiments confirm these differences: a significant increase of the duration of the molt cycle is observed in animals translocated to lower calcium concentrated waters and vice-versa whereas no significant difference is observed between controls and animals translocated within comparably calcium concentrated waters. The causes of such an adaptative diversity between Gammarus fossarum populations will be researched at the genetic level, namely through mitochondrial DNA investigations. (author). 25 refs., 2 tabs., 2 figs

  1. Intracellular calcium ions as regulators of renal tubular sodium transport.

    Science.gov (United States)

    Windhager, E; Frindt, G; Yang, J M; Lee, C O

    1986-09-15

    This review addresses the putative role of intracellular calcium ions in the regulation of sodium transport by renal tubules. Cytoplasmic calcium-ion activities in proximal tubules of Necturus are less than 10(-7) M and can be increased by lowering the electrochemical potential gradient for sodium ions across the peritubular cell membrane, or by addition of quinidine or ionomycin to peritubular fluid. Whereas lowering of the peritubular Na concentration increases cytosolic [Ca++] and [H+], ionomycin, a calcium ionophore, raises intracellular [Ca++] without decreasing pHi. The intracellular calcium-ion level is maintained by transport processes in the plasma membrane and membranes of intracellular organelles, as well as by calcium-binding proteins. Calcium ions inhibit net transport of sodium by reducing the rate of sodium entry across the luminal cell membrane. In the collecting tubule this inhibition is caused, at least in part, by an indirect reduction in the activity of the amiloride-sensitive sodium channel. PMID:2430134

  2. Responses of milk quality to roasted soybeans, calcium soap and organic mineral supplementation in dairy cattle diets

    OpenAIRE

    Adawiah; Toha Sutardi; Toto Toharmat; Wasmen Manalu; Nahrowi

    2006-01-01

    Milk quality is affected by feed nutrient either macronutrient or micronutrient. Roasted soayabeans and calcium soap were to increase supply by pas protein and fat to dairy cattle. Thus, organic mineral was to increase bioavailability of feed mineral to animal. The objective of this study was to evaluate roasted soybean, mineral soap and organic mineral supplementation on milk quality of dairy cattle. Twenty lactating Frisian Holstein cows (initial weight 361.4 ± 40.39 kg) were assigned in...

  3. Inositol trisphosphate and thapsigargin discriminate endoplasmic reticulum stores of calcium in rat brain

    DEFF Research Database (Denmark)

    Verma, A; Hirsch, D J; Hanley, M R;

    1990-01-01

    ATP dependent Ca2+ accumulation into oxalate-loaded rat brain microsomes is potently inhibited by thapsigargin with an IC50 of 2 nM and maximal inhibition at 10 nM. Approximately 15% of the total A23187-releasable microsomal calcium store is insensitive to thapsigargin concentrations up to 100...... microM. Inositol-1,4,5-trisphosphate (IP3) maximally inhibits 40% of the net Ca2+ accumulation by whole brain microsomes. Its effects are non-additive with thapsigargin suggesting that the IP3-sensitive Ca2+ pool is a subset of the thapsigargin sensitive Ca2+ pool. Marked regional differences occur...

  4. [Effects of the treatment of coffee pulp, fresh or ensilaged, with calcium hydroxide, on its nutritive value].

    Science.gov (United States)

    Gómez-Brenes, R; Bendaña, G; González, J M; Jarquín, R; Braham, J E; Bressani, R

    1988-03-01

    This study was carried out to determine the effects of the addition of calcium hydroxide on the chemical composition and nutritive value of fresh or ensilaged coffee pulp. Fresh or ensilaged pulp were mixed with 1, 2 and 3% of calcium hydroxide. The process was carried out during 0 and 16 hr, after which time the treated pulp was sun-dried for 36 hr until moisture content reached 12%. These samples were then analyzed for their proximate chemical composition and for some minerals (Ca, P, Na, K), as well as for caffeine, tannins and chlorogenic and caffeic acids content. Diets were then prepared from these materials, containing 15% protein and 15 or 30% fresh or ensilaged coffee pulp, and offered to weanling rats during six weeks. Information required on weight gain, food conversion, apparent digestibility and toxicity of the diets was recorded. Results of the chemical analysis revealed that the main changes found in both types of pulp as a result of the calcium hydroxide treatment were the following: a decrease in ether extract (from 4.0 to 2.5 g/100 g), crude fiber (from 18.3 to 11.9 g/100 g) and protein content (from 12.3 to 8.6 g/100 g) in an inverse relation to the amount of calcium hydroxide used. The amount of ash increased, fluctuated between 5.5 and 15.4%, depending on the amount of calcium hydroxide used. The latter affected the Ca:P ratio in the diets, where an average ratio of 7.2:1 was found in the control pulp (0% calcium hydroxide) and 59.0:1 in those treated with the highest amount of calcium hydroxide (3%). Regarding the caffeine, tannins and chlorogenic and caffeic acids contents, calcium hydroxide was effective in decreasing only tannins, more so in the fresh than in the ensilaged pulp; the decrease was in direct proportion to the amount of calcium hydroxide added and to the length of the Ca(OH)2 treatment. The results of the biological assays showed that the addition of Ca(OH)2 in either of the two time periods used and at either of the

  5. Mortar and concrete based on calcium sulphate binders

    OpenAIRE

    Bakker, J.J.F.; Brouwers, H. J. H.

    2006-01-01

    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For the calcinations of Portland cement, temperatures up to 1480 oC are needed, while the calcination of for instance hemihydrate requires a temperature of 170 oC

  6. Exocrine pancreatic enzyme and calcium secretion in health and pancreatitis.

    OpenAIRE

    Clain, J E; Barbezat, G O; Marks, I N

    1981-01-01

    Calcium, enzyme, and total protein secretion were measured in secretin stimulated pancreatic juice in health, "early" chronic pancreatitis, and in chronic calcific pancreatitis. Increased concentrations of trypsin, total protein, and calcium, and increased outputs of calcium and protein were shown to be present in the "early" stages of the disease, indicating that an environment conducive to the formation of protein plugs and possibly later calcification already exists.

  7. Concurrent Imaging of Synaptic Vesicle Recycling and Calcium Dynamics

    OpenAIRE

    Li, Haiyan; Foss, Sarah M.; Dobryy, Yuriy L.; Park, C. Kevin; Hires, Samuel Andrew; Shaner, Nathan C.; Tsien, Roger Y.; Osborne, Leslie C.; Voglmaier, Susan M.

    2011-01-01

    Synaptic transmission involves the calcium dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-sh...

  8. Concurrent imaging of synaptic vesicle recycling and calcium dynamics.

    OpenAIRE

    Haiyan eLi; Foss, Sarah M.; Yuriy eDobryy; C. Kevin ePark; Samuel Andrew Hires; Shaner, Nathan C.; Tsien, Roger Y.; Osborne, Leslie C.; Voglmaier, Susan M.

    2011-01-01

    Synaptic transmission involves the calcium-dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-...

  9. Control of calcium carbonate precipitation in anaerobic reactors.

    OpenAIRE

    Langerak, van, B.

    1998-01-01

    Anaerobic treatment of waste waters with a high calcium content may lead to excessive precipitation of calcium carbonate. So far, no proper methods were available to predict or reduce the extent of precipitation in an anaerobic treatment system. Moreover, it also was not clear to what extent precipitation in an anaerobic reactor can be tolerated because adequate knowledge on the structure and quality of methanogenic sludges with high calcium carbonate content was lacking. In this thesis, the ...

  10. Validation of two food frequency questionnaires for dietary calcium assessment

    OpenAIRE

    Andrea, Hacker-Thompson; Robertson, Trina P.; Sellmeyer, Deborah E.

    2009-01-01

    Easily utilized questionnaires estimating dietary calcium intake would be a valuable asset to promoting skeletal health and a helpful research tool. Two calcium questionnaires, one online and one printed, were each compared to dietary calcium intake measured by a three-day diet record. Women completed the questionnaires in a randomized order and kept a 3-day food record at home, returning it by mail. The ethnicity of the 140 study participants was 102 Caucasian, 12 African American, 16 Asian,...

  11. Radially expanding transglial calcium waves in the intact cerebellum

    OpenAIRE

    Hoogland, Tycho M; Kuhn, Bernd; Göbel, Werner; Huang, Wenying; Nakai, Junichi; HELMCHEN, Fritjof; Flint, Jane; Wang, Samuel S.-H.

    2009-01-01

    Multicellular glial calcium waves may locally regulate neural activity or brain energetics. Here, we report a diffusion-driven astrocytic signal in the normal, intact brain that spans many astrocytic processes in a confined volume without fully encompassing any one cell. By using 2-photon microscopy in rodent cerebellar cortex labeled with fluorescent indicator dyes or the calcium-sensor protein G-CaMP2, we discovered spontaneous calcium waves that filled approximately ellipsoidal domains of ...

  12. Preparation and biological efficacy of haddock bone calcium tablets

    Institute of Scientific and Technical Information of China (English)

    霍健聪; 邓尚贵; 谢超; 童国忠

    2010-01-01

    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...

  13. Should We Prescribe Calcium Supplements For Osteoporosis Prevention?

    OpenAIRE

    Reid, Ian R

    2014-01-01

    Advocacy for the use of calcium supplements arose at a time when there were no other effective interventions for the prevention of osteoporosis. Their promotion was based on the belief that increasing calcium intake would increase bone formation. Our current understandings of the biology of bone suggest that this does not occur, though calcium does act as a weak antiresorptive. Thus, it slows postmenopausal bone loss but, despite this, recent meta-analyses suggest no significant prevention of...

  14. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    OpenAIRE

    Mohammadi, Z; Shalavi, S.; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5...

  15. Treatment for calcium channel blocker poisoning: A systematic review

    OpenAIRE

    St-Onge, M.; Dubé, P.-A.; Gosselin, S.; Guimont, C; Godwin, J; Archambault, P. M.; Chauny, J.-M.; Frenette, A. J.; Darveau, M.; Le sage, N.; Poitras, J.; Provencher, J.; Juurlink, D. N.; Blais, R

    2014-01-01

    Context Calcium channel blocker poisoning is a common and sometimes life-threatening ingestion. Objective To evaluate the reported effects of treatments for calcium channel blocker poisoning. The primary outcomes of interest were mortality and hemodynamic parameters. The secondary outcomes included length of stay in hospital, length of stay in intensive care unit, duration of vasopressor use, functional outcomes, and serum calcium channel blocker concentrations. Methods Medline/Ovid, PubMed, ...

  16. An atlas of Calcium triplet spectra of active galaxies

    CERN Document Server

    Garcia-Rissmann, A; Asari, N V; Fernandes, R C; Schmitt, H; González-Delgado, R M; Storchi-Bergmann, T

    2005-01-01

    We present a spectroscopic atlas of active galactic nuclei covering the region around the 8498, 8542, 8662 Calcium triplet (CaT) lines. The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, 3 Starburst and 6 normal galaxies. The spectra pertain to the inner ~300 pc in radius, and thus sample the central kinematics and stellar populations of active galaxies. The data are used to measure stellar velocity dispersions (sigma_star) both with cross-correlation and direct fitting methods. These measurements are found to be in good agreement with each-other and with those in previous studies for objects in common. The CaT equivalent width is also measured. We find average values and sample dispersions of W_CaT of 4.6+/-2.0, 7.0 and 7.7+/-1.0 angstrons for Seyfert 1s, Seyfert 2s and normal galaxies, respectively. We further present an atlas of [SIII]\\lambda 9069 emission line profiles for a subset of 40 galaxies. These data are analyzed in a companion paper which addresses the connection between ...

  17. Calcium pentosan polysulfate is a multifaceted exosite inhibitor of aggrecanases.

    Science.gov (United States)

    Troeberg, Linda; Fushimi, Kazunari; Khokha, Rama; Emonard, Hervé; Ghosh, Peter; Nagase, Hideaki

    2008-10-01

    Degradation of the cartilage proteoglycan aggrecan is a key early event in the development of osteoarthritis. Adamalysin with thrombospondin motifs (ADAMTS) -4 and ADAMTS-5 are considered to be the main enzymes responsible for aggrecan breakdown, making them attractive drugs targets. Here we show that calcium pentosan polysulfate (CaPPS), a chemically sulfated xylanopyranose from beechwood, is a multifaceted exosite inhibitor of the aggrecanases and protects cartilage against aggrecan degradation. CaPPS interacts with the noncatalytic spacer domain of ADAMTS-4 and the cysteine-rich domain of ADAMTS-5, blocking activity against their natural substrate aggrecan with inhibitory concentration 50 values of 10-40 nM but only weakly inhibiting hydrolysis of a nonglycosylated recombinant protein substrate. In addition, CaPPS increased cartilage levels of tissue inhibitor of metalloproteinases-3 (TIMP-3), an endogenous inhibitor of ADAMTS-4 and -5. This was due to the ability of CaPPS to block endocytosis of TIMP-3 mediated by low-density lipoprotein receptor-related protein. CaPPS also increased the affinity of TIMP-3 for ADAMTS-4 and -5 by more than 100-fold, improving the efficacy of TIMP-3 as an aggrecanase inhibitor. Studies with TIMP-3-null mouse cartilage indicated that CaPPS inhibition of aggrecan degradation is TIMP-3 dependent. These unique properties make CaPPS a prototypic disease-modifying agent for osteoarthritis.

  18. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Ganesan Lavanya

    2015-01-01

    Full Text Available This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were 150×150×150 mm cubes, 100×200 mm cylinders, and 100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

  19. Calcium isotope analysis by mass spectrometry.

    Science.gov (United States)

    Boulyga, Sergei F

    2010-01-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of (41)Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use

  20. Calcium regulates caveolin-1 expression at the transcriptional level

    International Nuclear Information System (INIS)

    Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca2+/calcineurin/NFAT.

  1. Effect of galactooligosaccharides on calcium absorption in rats.

    Science.gov (United States)

    Chonan, O; Watanuki, M

    1995-02-01

    The effect of transgalactosylated oligosaccharides (TOS), which are oligosaccharides that are unhydrolyzed in the small intestine and are fermented by the intestinal bacteria, on calcium absorption was examined in male Wistar rats for 10 days. The apparent calcium absorption ratios and the apparent retention ratios were significantly higher in the rats fed TOS-containing diets (5 or 10 g/100 g of diet). In the second experiment, the cecum was ligated in situ and calcium absorption from the cecum was observed after injecting TOS into the cecal lumen. Four hours after the injection, the calcium concentration in the cecal vein of the rats given TOS was significantly higher than that of the control. The calcium content in the liquid phase of the cecal lumen and the liquid phase weight were also increased by the injection of TOS into the cecum. Although the extent of calcium absorption from the cecum of rats fed TOS is due to overall calcium absorption is not known, under the experimental conditions used in the present study the stimulatory effect of TOS on calcium absorption may be partly associated with increased solubility of calcium and the fluid content in the intestinal lumen.

  2. On the growth of calcium tartrate tetrahydrate single crystals

    Indian Academy of Sciences (India)

    X Sahaya Shajan; C Mahadevan

    2004-08-01

    Calcium tartrate single crystals were grown using silica gel as the growth medium. Calcium formate mixed with formic acid was taken as the supernatant solution. It was observed that the nucleation density was reduced and the size of the crystals was improved to a large extent compared to the conventional way of growing calcium tartrate crystals with calcium chloride. The role played by formate–formic acid on the growth of crystals is discussed. The grown crystals were characterized by atomic absorption spectroscopy (AAS), X-ray diffraction analysis (XRD), microhardness measurement, Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and differential thermal analysis (DTA). The results obtained are compared with the previous work.

  3. Should we prescribe calcium supplements for osteoporosis prevention?

    Science.gov (United States)

    Reid, Ian R

    2014-02-01

    Advocacy for the use of calcium supplements arose at a time when there were no other effective interventions for the prevention of osteoporosis. Their promotion was based on the belief that increasing calcium intake would increase bone formation. Our current understandings of the biology of bone suggest that this does not occur, though calcium does act as a weak antiresorptive. Thus, it slows postmenopausal bone loss but, despite this, recent meta-analyses suggest no significant prevention of fractures. In sum, there is little substantive evidence of benefit to bone health from the use of calcium supplements. Against this needs to be balanced the likelihood that calcium supplement use increases cardiovascular events, kidney stones, gastrointestinal symptoms, and admissions to hospital with acute gastrointestinal problems. Thus, the balance of risk and benefit seems to be consistently negative. As a result, current recommendations are to obtain calcium from the diet in preference to supplements. Dietary calcium intake has not been associated with the adverse effects associated with supplements, probably because calcium is provided in smaller boluses, which are absorbed more slowly since they come together with quantities of protein and fat, resulting in a slower gastric transit time. These findings suggest that calcium supplements have little role to play in the modern therapeutics of osteoporosis, which is based around the targeting of safe and effective anti-resorptive drugs to individuals demonstrated to be at increased risk of future fractures. PMID:24707464

  4. FLIPR assays of intracellular calcium in GPCR drug discovery

    DEFF Research Database (Denmark)

    Hansen, Kasper Bø; Bräuner-Osborne, Hans

    2009-01-01

    Fluorescent dyes sensitive to changes in intracellular calcium have become increasingly popular in G protein-coupled receptor (GPCR) drug discovery for several reasons. First of all, the assays using the dyes are easy to perform and are of low cost compared to other assays. Second, most non......-Galpha(q)-coupled GPCRs can be tweaked to modulate intracellular calcium by co-transfection with promiscuous or chimeric/mutated G proteins making the calcium assays broadly applicable in GPCR research. Third, the price of instruments capable of measuring fluorescent-based calcium indicators has become significantly less...

  5. THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

    Institute of Scientific and Technical Information of China (English)

    于建; 夏延致

    2009-01-01

    Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during ...

  6. Serum calcium levels are not associated with coronary heart disease

    Directory of Open Access Journals (Sweden)

    Jin Y

    2013-09-01

    Full Text Available Yuelong Jin,* Lianping He,* Quanhai Wang, Yan Chen, Xiaohua Ren, Hui Tang, Xiuli Song, Lingling Ding, Qin Qi, Zhiwei Huang, Jiegen Yu, Yingshui Yao Department of Preventive Medicine, Wannan Medical College, Wuhu, People's Republic of China *These authors contributed equally to this work Background: Numerous studies have reported that low calcium intake is related to a higher prevalence of cardiovascular disease. However, the relationship between serum calcium and coronary heart disease is unclear. The purpose of this study was to compare serum calcium levels in patients with coronary heart disease and those in healthy individuals. Methods: This retrospective, case-control study conducted in the People's Republic of China comprised 380 cases and 379 controls. Serum calcium levels, blood lipids, and anthropometric measurements were measured in both groups. The Student's unpaired t-test or Chi-square test was used to compare differences between cases and controls. Pearson's partial correlation coefficient was used to determine the association between serum calcium, blood lipids, and blood pressure in both groups. Results: Our results indicate that the average level of serum calcium in cases was higher than in controls. Serum calcium levels showed no correlation with any parameter except for triglycerides in either group. Conclusion: Overall, these data suggest that serum calcium has no influence on coronary heart disease or triglyceride levels in the general population. Keywords: serum calcium, hypertension, blood lipids

  7. Calcium spray dryer waste management: Design guidelines: Final report

    Energy Technology Data Exchange (ETDEWEB)

    1987-09-01

    Calcium spray drying is a commercially available and applied technology used to control SO/sub 2/ emissions. This process is rapidly gaining utility acceptance. Because physical and chemical properties of wastes generated by calcium spray drying differ from those of conventional coal combustion by-products (fly ash and scrubber sludge) typical waste management practices may need to be altered. This report presents technical guidelines for designing and operating a calcium spray drying waste management system. Waste transfer, storage, pretreatment/conditioning, transport and disposal are addressed. The report briefly describes eighteen existing or planned calcium spray drying waste management systems. Results of waste property tests conducted as part of this study, and test data from other studies are reported and compared. Conceptual designs of both new and retrofit calcium spray drying waste management systems also are presented to demonstrate the economic impact of spray drying on waste management. Parametric cost sensitivity analyses illustrate the impact of significant design parameters on waste management costs. Existing calcium spray drying waste management experiences, as well as spray drying waste property data provided the basis for guideline development. Because existing calcium spray drying facilities burn low sulfur coal, this report is considered applicable only to calcium spray drying wastes produced from low sulfur coal. At this time, calcium spray drying is not expected to be feasible for high sulfur coal applications.

  8. Diagram of Calcium Movement in the Human Body

    Science.gov (United States)

    2002-01-01

    This diagram shows the normal pathways of calcium movement in the body and indicates changes (green arrows) seen during preliminary space flight experiments. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. To better understand how and why weightlessness induces bone loss, astronauts have participated in a study of calcium kinetics -- that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  9. Vitamin D and Calcium Supplementation to Prevent Fractures

    Science.gov (United States)

    Understanding Task Force Recommendations Vitamin D and Calcium Supplementation to Prevent Fractures The U.S. Preventive Services Task Force (Task Force) has issued final recommendations on Vitamin ...

  10. 40 CFR 424.54-424.56 - [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true 424.54-424.56 Section 424.54-424.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Other Calcium Carbide Furnaces Subcategory §§ 424.54-424.56...

  11. 40 CFR 415.35 - New source performance standards (NSPS).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true New source performance standards (NSPS). 415.35 Section 415.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Carbide...

  12. 40 CFR 415.31 - Specialized definitions. [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Specialized definitions. 415.31 Section 415.31 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Calcium Carbide Production...

  13. 40 CFR 52.920 - Identification of plan.

    Science.gov (United States)

    2010-07-01

    ... 6.46 Standards of Performance for Existing Ferroalloy and Calcium Carbide Production Facilities 10... of the Clean Air Act, 42 U.S.C. 7401, and 40 CFR part 51 to meet national ambient air quality... of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Material...

  14. 40 CFR 424.44-424.46 - [Reserved

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true 424.44-424.46 Section 424.44-424.46 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Covered Calcium Carbide Furnaces With Wet Air...

  15. Wheat bread enriched with organic calcium salts and inulin. A bread quality study.

    Science.gov (United States)

    Salinas, María V; Zuleta, Angela; Ronayne, Patricia; Puppo, María C

    2016-01-01

    The objective of this work was to study quality parameters of enriched wheat bread with calcium citrate (Ca3CI2) or lactate (CaLA2) and inulin (In), also to optimize bread formulation. Fermentation time (tf), specific volume (Vs), browning index of crust (BI) and crumb properties (moisture, alveolus, texture) were studied. Generally, tf and Vs decreased with prebiotic increment. Ca3CI2 did not change Vs at equal inulin quantity, whereas with CaLA2 smaller breads were obtained (at 6.5 % In). Moisture of crumbs decreased with an increase in Ca3CI2 (at ≤ 6.5 %); while for CaLA2 was more influenced by the prebiotic. Up to 6.5 % In, the addition of both salts decreased crumb firmness and increased cohesiveness. Using a desirability function, the optimum calcium-prebiotic bread obtained with Ca3CI2 contained 2.40 g/kg Ca and 7.49 % In and with CaLA2 presented 1.33 g/kg Ca and 4.68 % In. Breads of high-quality with higher calcium and prebiotic quantity were able to obtain with Ca3CI2.

  16. Hydrothermal and mechanochemical reactions of rice husk ash with calcium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Sugita, S.; Isojima, Y. [Hachinohe Institute of Technology, Aomori (Japan); Yu, Q. [Wuhan University of Technology, (Taiwan, Province of China)

    1998-05-01

    It is well known that a calcium silicate hydrate, commonly referred to as C-S-H gel, is important for cement to exhibit strength. Silica is present in rice husk ash to around 90%. When sufficiently sintered and crushed, rice husk ash mostly comprises amorphous silica having a large surface area. It is reactive, and is considered to contribute to improvement of concrete strength and durability. In this study, rice husk ash is reacted with calcium hydroxide under hydrothermal conditions or mechanochemical conditions at normal temperature, to synthesize Ca(1.5)SiO(3.5){center_dot}xH2O as one of the calcium silicate hydrates. It has an average particle size of 10{mu}m or smaller, which varies depending on synthesis method and condition. The compound synthesized at 40degC is composed of flocs having a porous structure and large specific surface area, as is the case with a C-S-H gel present in Portland cement paste. It loses the above structure and moisture in the fine pores gradually, when heated, but remains amorphous at up to 750degC. It is transformed into wollastonite, when heated to 780degC. 7 refs., 8 figs., 3 tabs.

  17. Environmental Problems From Tea Cultivation in Japan and a Control Measure Using Calcium Cyanamide

    Institute of Scientific and Technical Information of China (English)

    K.OH; T.KATO; LI Zhong-Pei; LI Fa-Yun

    2006-01-01

    A field experiment, involving lime N (calcium cyanamide, CaCN2) fertilization as a control measure, was conducted to study environmental problems induced by long-term heavy N application in Japanese tea fields. Long-term tea cultivation caused serious soil acidification. Seventy-seven percent of the 70 tea fields investigated had soil pH values below 4.0, and9% below 3.0, with the lowest value of 2.7. Moreover, excess N application in tea fields put a threat to plant growth,induced serious nitrate contamination to local water, and caused high nitrous oxide loss. Compared with the conventional high N application treatment (1 100 kg N ha-1) without lime N, the low N application (400 kg N ha-1) with calcium cyanamide effectively stopped soil acidification as well as achieved the same or slightly higher levels in tea yield and in total N and amino acid contents of tea shoots. The application of calcium cyanamide could be a suitable fertilization for the prevention of environmental problems in tea cultivation.

  18. Adaptation of two different calcium hydroxide bases under a composite restoration.

    Science.gov (United States)

    Papadakou, M; Barnes, I E; Wassell, R W; McCabe, J F

    1990-10-01

    A preliminary scanning electron microscope (SEM) study was carried out to investigate how the adaptation of two calcium hydroxide bases (one chemically cured, one light cured) was affected by the polymerization contraction of a supervening light-cured composite resin restoration. Occlusal cavities were prepared in 40 sound extracted human premolars, divided into two equal groups. In the first group a chemically cured calcium hydroxide (Dycal, De Trey Dentsply, Konstanz, FRG) was placed as a base. In the second group a new light-cured calcium hydroxide product (Prisma VLC Dycal, De Trey Dentsply) was used. The restorations were completed with an acid-etched, incrementally placed composite resin. The specimens were sectioned vertically and debrided. A replica was made of each half-tooth. The interfaces between composite resin/base and base/dentine were viewed and photographed in the SEM. The marginal adaptation at these two interfaces was classified into three categories according to the extent of the gaps that were observed. Prisma VLC Dycal base was found to be pulled away from the dentine floor of the cavity as a result of an apparent adhesion to the composite resin during polymerization contraction. Dycal was better adapted to the cavity floor than Prisma VLC Dycal. Disorganization of the resin-bonded Prisma VLC Dycal was minimal even after acid etching the enamel, sectioning and ultrasonic debridement. Dycal appeared to be more friable, and occasionally exhibited marked disorganization as a result of these procedures.

  19. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor

    International Nuclear Information System (INIS)

    The gas-solid reaction and breakthrough curve of CO2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO2 capture at 550 deg. C. Calcium oxide sorbent after reaction can be easily regenerated at 900 deg. C by pure N2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO2 were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  20. Nanostructure of Calcium Silicate Hydrates in Cements

    KAUST Repository

    Skinner, L. B.

    2010-05-11

    Calcium silicate hydrate (CSH) is the major volume phase in the matrix of Portland cement concrete. Total x-ray scattering measurements with synchrotron x rays on synthetic CSH(I) shows nanocrystalline ordering with a particle diameter of 3.5(5) nm, similar to a size-broadened 1.1 nm tobermorite crystal structure. The CSH component in hydrated tricalcium silicate is found to be similar to CSH(I). Only a slight bend and additional disorder within the CaO sheets is required to explain its nanocrystalline structure. © 2010 The American Physical Society.

  1. Distal Renal Tubular Acidosis and Calcium Nephrolithiasis

    Science.gov (United States)

    Moe, Orson W.; Fuster, Daniel G.; Xie, Xiao-Song

    2008-09-01

    Calcium stones are commonly encountered in patients with congenital distal renal tubular acidosis, a disease of renal acidification caused by mutations in either the vacuolar H+-ATPase (B1 or a4 subunit), anion exchanger-1, or carbonic anhydrase II. Based on the existing database, we present two hypotheses. First, heterozygotes with mutations in B1 subunit of H+-ATPase are not normal but may harbor biochemical abnormalities such as renal acidification defects, hypercalciuria, and hypocitraturia which can predispose them to kidney stone formation. Second, we propose at least two mechanisms by which mutant B1 subunit can impair H+-ATPase: defective pump assembly and defective pump activity.

  2. Calcium phosphate ceramics in drug delivery

    Science.gov (United States)

    Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

    2011-04-01

    Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

  3. High Performance Calcium Titanate Nanoparticle ER Fluids

    Science.gov (United States)

    Wang, Xuezhao; Shen, Rong; Wen, Weijia; Lu, Kunquan

    A type of calcium titanate (CTO) nanoparticles was synthesized by means of wet chemical method [1] without coating on the particles. The CTO/silicone oil ER fluid exhibits excellent electrorheological properties: high shear stress (~50-100 kPa) under dc electric field, a low current density (less than 2μA/cm2 at 5kV/mm), and long term stability against sedimentation. Although there are not special additives in the ER fluids, it is found from the chemical analysis that a trace of alkyl group, hydroxyl group, carbonyl group and some ions is remained in the particles which may dominate the ER response.

  4. Effect of dairy calcium or supplementary calcium intake on postprandial fat metabolism, appetite, and subsequent energy intake

    DEFF Research Database (Denmark)

    Lorenzen, J.K.; Nielsen, S.; Holst, J.J.;

    2007-01-01

    Background: High calcium intake has been shown to increase fecal fat excretion. Objective: Our aim was to examine whether a high calcium intake from dairy products or from supplements affects postprandial fat metabolism and appetite through fat malabsorption. Design: Four different isocaloric meals...... were tested in 18 subjects according to a randomized crossover design. The test meals contained high (HC meal: 172 mg/MJ), medium (MC meal: 84 mg/MJ), or low (LC meal: 15 mg/MJ) amounts of calcium from dairy products or a high amount of calcium given as a calcium carbonate supplement (Suppl meal: 183...... and approximate to 15% lower after the MC meal (P = 0.0495) and approximate to 17% lower after the HC meal (P = 0.02) than after the Suppl meal. No consistent effects of calcium on appetite sensation, or on energy intake at the subsequent meal, or on the postprandial responses of cholecystokinin, glucagon...

  5. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis

    DEFF Research Database (Denmark)

    Bro, S; Rasmussen, R A; Handberg, J;

    1998-01-01

    into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium carbonate (US$6.00/d v US$0.65/d). Calcium ketoglutarate may be an effective and safe alternative to treatment with aluminum......The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main...... outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate...

  6. 21 CFR 101.72 - Health claims: calcium, vitamin D, and osteoporosis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Health claims: calcium, vitamin D, and....72 Health claims: calcium, vitamin D, and osteoporosis. (a) Relationship between calcium, vitamin D, and osteoporosis. An inadequate intake of calcium or calcium and vitamin D contributes to low...

  7. Effect of resorbable calcium aluminate ceramics on regulation of calcium and phosphorus in rats.

    Science.gov (United States)

    Carvalho, B A; Bajpai, P K; Graves, G A

    1976-06-01

    Ions released from resorbable ceramics could be toxic to the animal. Experiments were designed to study the effect of implanting three different weights of porous resorbable calcium aluminate ceramics (0.172, 0.332, and 0.504 g) in rats for a total duration of 300 days. Gross and microscopic examination of heart, liver, kidneys, trachea with thyroid, and muscle adjacent to the implant did not show any pathological changes. Calcium and inorganic phosphate content of bone, serum and urine were not affected by the implants. Urine hydroxyproline excretion did not change in the animals implanted with ceramics. Animals implanted with 0.332 g of ceramics had a significantly higher serum alkaline phosphatase activity than the control animals. Resorption of calcium and depositon of inorganic phosphates in the implanted ceramics suggested that ions were being exchanged with the body fluids. Implantation of 0.172 to 0.332 g porous resorbable calcium aluminate ceramic was not toxic to the animal.

  8. Tree species effects on calcium cycling: The role of calcium uptake in deep soils

    NARCIS (Netherlands)

    Dijkstra, F.A.; Smits, M.M.

    2002-01-01

    Soil acidity and calcium (Ca) availability in the surface soil differ substantially beneath sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) trees in a mixed forest in northwestern Connecticut. We determined the effect of pumping of Ca from deep soil (rooting zone below 20-cm mine

  9. Effect of nano-calcium-enriched milk on calcium metabolism in ovariectomized rats.

    Science.gov (United States)

    Park, Heung-Sik; Ahn, Joungjwa; Kwak, Hae-Soo

    2008-09-01

    This study was designed to examine the effect of different kinds of calcium enrichment on serum and urine indices of mineral status in ovariectomized rats. Twenty-four 7-week-old Sprague-Dawley female rats were divided into four groups, ovariectomized, and fed diets containing the following: (1) Control, non-Ca-enriched milk; (2) OVX1, calcium carbonate-enriched milk; (3) OVX2, ionized Ca-enriched milk; and (4) OVX3, nano-Ca-enriched milk. After 18 weeks of feeding, the food efficiency ratio in the nano-Ca-fed group was significantly lower compared with those in the Control and OVX2 groups. There was no difference in serum and fecal Ca among the groups. The bone/total alkaline phosphatase ratio was significantly higher in rats fed milk enriched with nano-Ca (59%) and calcium carbonate (62%) than in control (44%) animals. Urinary Ca was the highest in the nano-Ca-enriched group; however, urinary excretions of deoxypyridinoline and hydroxyproline were significantly decreased in the nano-Ca-enriched group. The present results indicate that consumption of nano-Ca-enriched milk resulted in an increase of urinary excretion of calcium and a decrease in deoxypyridinoline and hydroxyproline in ovariectomized rats.

  10. The Effect of Calcium on the Binding of Calmodulin to Calcium/Calmodulin Protein Kinase II.

    Science.gov (United States)

    Porta, Angela R.

    2000-01-01

    Introduces a follow-up laboratory experiment demonstrating the formation change when calcium binds to calmodulin. This conformation change allows this complex to bind to a target protein. Presents the necessary information to conduct the experiment and discusses the results. (YDS)

  11. Ionized calcium measurements are influenced by albumin - should ionized calcium be corrected?

    DEFF Research Database (Denmark)

    Larsen, Trine R; Galthen-Sørensen, Mathias; Antonsen, Steen

    2014-01-01

    Abstract Measurement of ionized calcium (CaI) has been reported to be dependent on albumin concentration. We examined the correlation between albumin and CaI measured on different ion selective electrode analyzers and in different groups of patients in a large dataset, extracted from the laboratory...

  12. [Dynamics of calcium metabolism and calcium-regulating hormones in pregnancy-induced hypertension].

    Science.gov (United States)

    Ohara, N; Yamasaki, M; Morikawa, H; Ueda, Y; Mochizuki, M

    1986-08-20

    Serum concentrations of total calcium, ionized calcium and inorganic phosphorus in severe PIH were significantly lower than those in normal pregnancy during the 3rd trimester of pregnancy and continued to be low even at puerperium. On the other hand, serum concentrations of parathyroid hormone in severe PIH were significantly higher during the 3rd trimester of pregnancy and decreased at puerperium. Any remarkable differences in serum calcitonin levels were not found between severe PIH and normal pregnancy through the last trimester of pregnancy and puerperium. Serum concentrations of 1 alpha, 25-(OH)2 vitamin D3 increased significantly in the 3rd trimester of normal pregnancy, but in severe PIH, their increase was not observed, remaining at the normal levels of non-pregnant women. The kidney functions in the both groups were within the normal limits of non-pregnant women, but placental dysfunction was observed in severe PIH. These results suggest that the decrease in serum calcium and phosphorus levels might have occurred as a result of the decrease in the absorption of calcium and phosphorus from the intestine due to the decrease in serum 1 alpha, 25-(OH)2 vitamin D3 levels and that low serum 1 alpha, 25-(OH)2 vitamin D3 concentrations might be caused by the disturbance of the synthesis in the placenta rather than in the kidney. PMID:3781066

  13. Constraining the cause of the end-Guadalupian extinction with coupled records of carbon and calcium isotopes

    Science.gov (United States)

    Jost, Adam B.; Mundil, Roland; He, Bin; Brown, Shaun T.; Altiner, Demir; Sun, Yadong; DePaolo, Donald J.; Payne, Jonathan L.

    2014-06-01

    A negative δC13 excursion in carbonate sediments near the Guadalupian/Lopingian (Middle/Late Permian) boundary has been interpreted to have resulted from a large carbon cycle disturbance during the end-Guadalupian extinction event (ca. 260 Ma). However, the carbon isotope data alone are insufficient to uniquely determine the type and magnitude of perturbation to the global carbon cycle. Calcium isotopes can be used to further constrain the cause of a carbon isotope excursion because the carbon and calcium cycles are coupled via CaCO3 burial. In this study, we present coupled carbon and calcium isotope records from three Guadalupian-Lopingian (G/L) sections in China (Penglaitan and Chaotian) and Turkey (Köserelik Tepe). The δC13 and δCa44/40 records differ among our studied sections and do not co-vary in the same manner. No section shows δC13 and δCa44/40 changes consistent with massive, rapid volcanic CO2 emissions or methane clathrate destabilization. Additionally, many sections with large (>3‰) changes in δC13 exhibit δO18 evidence for diagenetic alteration. Only one section exhibits a large excursion in the δCa44/40 of limestone but the absence of a similar excursion in the δCa44/40 of conodont apatite suggests that the limestone excursion reflects a mineralogical control rather than a perturbation to the global calcium cycle. Hence, we interpret the large isotopic changes observed in some sections to have resulted from local burial conditions or diagenetic effects, rather than from a large carbon and calcium cycle disturbance. Perturbations to the global carbon and calcium cycles across the G/L transition were much less intense than the disturbances that occurred across the subsequent Permian-Triassic boundary. This finding is consistent with the much smaller magnitude of the end-Guadalupian extinction relative to the end-Permian.

  14. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling

    OpenAIRE

    Kornélia Szebényi; András Füredi; Orsolya Kolacsek; Enikő Pergel; Zsuzsanna Bősze; Balázs Bender; Péter Vajdovich; József Tóvári; László Homolya; Gergely Szakács; László Héja; Ágnes Enyedi; Balázs Sarkadi; Ágota Apáti; Orbán, Tamás I.

    2015-01-01

    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, an...

  15. Calcium-sensing receptor regulates stomatal closure through hydrogen peroxide and nitric oxide in response to extracellular calcium in Arabidopsis

    OpenAIRE

    Wang, Wen-Hua; Yi, Xiao-Qian; Han, Ai-Dong; Liu, Ting-Wu; Chen, Juan; Wu, Fei-Hua; Dong, Xue-Jun; He, Jun-Xian; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-01-01

    The Arabidopsis calcium-sensing receptor CAS is a crucial regulator of extracellular calcium-induced stomatal closure. Free cytosolic Ca2+ (Ca2+ i) increases in response to a high extracellular calcium (Ca2+ o) level through a CAS signalling pathway and finally leads to stomatal closure. Multidisciplinary approaches including histochemical, pharmacological, fluorescent, electrochemical, and molecular biological methods were used to discuss the relationship of hydrogen peroxide (H2O2) and nitr...

  16. The increasing of enamel calcium level after casein phosphopeptideamorphous calcium phosphate covering

    Directory of Open Access Journals (Sweden)

    Widyasri Prananingrum

    2012-06-01

    Full Text Available Background: Caries process is characterized by the presence of demineralization. Demineralization is caused by organic acids as a result of carbohydrate substrate fermentation. Remineralization is a natural repair process for non-cavitated lesions. Remineralization occurs if there are Ca2+ and PO43- ions in sufficient quantities. Casein-amorphous calcium phosphate phosphopeptide (CPP-ACP is a paste material containing milk protein (casein, that actually contains minerals, such as calcium and phosphate. The casein ability to stabilize calcium phosphate and enhance mineral solubility and bioavailability confers upon CPP potential to be biological delivery vehicles for calcium and phosphate. Purpose: The aim of this study was to determine the calcium levels in tooth enamel after being covered with CPP-ACP 2 times a day for 3, 14 and 28 days. Methods: Sample were bovine incisors of 3 year old cows divided into 4 groups, namely group I as control group, group II, III and IV as treatment groups covered with CPP-ACP 2 times a day. All of those teeth were then immersed in artificial saliva. Group II was immersed for 3 days, while group III was immersed for 14 days, and group IV was immersed for 28 days. One drop of CPP-ACP was used to cover the entire labial surface of teeth. The measurement of the calcium levels was then conducted by using titration method. All data were analyzed by One- Way ANOVA test with 5% degree of confidence. Results: The results showed significant difference of the calcium levels in tooth enamel of those groups after covered with CPP-ACP 2 times a day for 3, 14 and 28 days (p = 0.001. There is also significant difference of the calcium levels in tooth enamel of those treatment groups and the control group (p = 0.001. Conclusion: The calcium levels of tooth enamel are increased after covered with CPP-ACP 2 times a day for 3, 14 and 28 days.Latar belakang: Proses terjadinya karies gigi ditandai oleh adanya demineralisasi

  17. Calcium citrate: a new biomaterial that can enhance bone formation in situ

    Institute of Scientific and Technical Information of China (English)

    WANG Li-ming; WANG Wei; LI Xiu-cui; PENG Lei; LIN Zhong-qin; X(ü) Hua-zi

    2012-01-01

    Objective: To investigate the effect of a new biomaterial combining calcium citrate and recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone regeneration in a bone defect rabbit model.Methods: Totally 30 male New Zealand white rabbits were randomly and equally divided into calcium citraterhBMP-2 (CC-rhBMP-2) group and rhBMP-2 only group.Two 10 mm-long and 5 mm-deep bone defects were respectively created in the left and right femoral condyles of the rabbits.Subsequently 5 pellets of calcium citrate (10 mg)combined with rhBMP-2 (2 mg) or rhBMP-2 alone were implanted into the bone defects and compressed with cotton swab.Bone granules were obtained at 2,4 and 6 weeks after procedure and received histological analysis.LSD t-test and a subsequent t-test were adopted for statistical analysis.Results: Histomorphometric analysis revealed newly formed bones,and calcium citrate has been absorbed in the treatment group.The percent of newly formed bone area in femoral condyle in control group and CC-rhBMP-2 group was respectively 31.73%±1.26% vs 48.21%±2.37% at 2 weeks; 43.40%±1.65% vs 57.32%±1.47% at 4 weeks,and 51.32%±7.80% vs 66.74%±4.05% at 6 weeks (P<0.05 for all).At 2 weeks,mature cancellous bone was observed to be already formed in the treatment group.Conclusion: From this study,it can be concluded that calcium citrate combined with rhBMP-2 signifcantly enhances bone regeneration in bone defects.This synthetic gelatin matrix stimulates formation of new bone and bone marrow in the defect areas by releasing calcium ions.

  18. Analysis of the effects of calcium or magnesium on voltage-clamp currents in perfused squid axons bathed in solutions of high potassium.

    Science.gov (United States)

    Rojas, E; Taylor, R E; Atwater, I; Bezanilla, F

    1969-10-01

    Isolated axons from the squid, Dosidicus gigas, were internally perfused with potassium fluoride solutions. Membrane currents were measured following step changes of membrane potential in a voltage-clamp arrangement with external isosmotic solution changes in the order: potassium-free artificial seawater; potassium chloride; potassium chloride containing 10, 25, 40 or 50, mM calcium or magnesium; and potassium-free artificial seawater. The following results suggest that the currents measured under voltage clamp with potassium outside and inside can be separated into two components and that one of them, the predominant one, is carried through the potassium system. (a) Outward currents in isosmotic potassium were strongly and reversibly reduced by tetraethylammonium chloride. (b) Without calcium or magnesium a progressive increase in the nontime-dependent component of the currents (leakage) occurred. (c) The restoration of calcium or magnesium within 15-30 min decreases this leakage. (d) With 50 mM divalent ions the steady-state current-voltage curve was nonlinear with negative resistance as observed in intact axons in isosmotic potassium. (e) The time-dependent components of the membrane currents were not clearly affected by calcium or magnesium. These results show a strong dependence of the leakage currents on external calcium or magnesium concentration but provide no support for the involvement of calcium or magnesium in the kinetics of the potassium system. PMID:5823216

  19. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis.

    Science.gov (United States)

    Bro, S; Rasmussen, R A; Handberg, J; Olgaard, K; Feldt-Rasmussen, B

    1998-02-01

    The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate calcium concentration of 1.25 mmol/L and a fixed alfacalcidol dose for at least 2 months. All had previously tolerated therapy with calcium carbonate. Of the 19 patients included, 10 completed both treatment arms. After 12 weeks of therapy, the mean (+/-SEM) plasma ionized calcium level was significantly lower in the ketoglutarate arm compared with the calcium carbonate arm (4.8+/-0.1 mg/dL v 5.2+/-0.1 mg/dL; P = 0.004), whereas the mean plasma phosphate (4.5+/-0.3 mg/dL v 5.1+/-0.1 mg/dL) and PTH levels (266+/-125 pg/mL v 301+/-148 pg/mL) did not differ significantly between the two treatment arms. Supplemental aluminum-aminoacetate was not required during calcium ketoglutarate treatment, while two patients needed this supplement when treated with calcium carbonate. Five of 17 (29%) patients were withdrawn from calcium ketoglutarate therapy within 1 to 2 weeks due to intolerance (anorexia, vomiting, diarrhea, general uneasiness), whereas the remaining 12 patients did not experience any side effects at all. The five patients with calcium ketoglutarate intolerance all had pre-existing gastrointestinal symptoms; four of them had received treatment with cimetidine or omeprazol before inclusion into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium

  20. Calcium homeostasis in low and high calcium water acclimatized Oreochromis mossambicus exposed to ambient and dietary cadmium

    OpenAIRE

    Pratap, H.B.; Wendelaar Bonga, S.E.

    2007-01-01

    The effects of cadmium administered via ambient water (10 mg/l) or food (10 mgCd/fish/day) on plasma calcium, corpuscles of Stannius and bony tissues of Oreochromis mossambicus acclimated to low calcium (0.2 mM) and high calcium (0.8 mM) water were studied for 2, 4, 14 and 35 days. In low calcium water acclimated fish, ambient cadmium induced significant hypocalcemia, while the structure and morphometry of type-1 and type-2 cells of corpuscles of Stannius were not affected on day 2 and 4. Sub...

  1. Effects of dietary clinoptilolite and calcium levels on uric acid and calcium blood concentrations and bone quality of commercial layers

    Directory of Open Access Journals (Sweden)

    DA Berto

    2013-06-01

    Full Text Available The objective of the present study was to evaluate the effect of clinoptilolite and calcium levels on uric acid and calcium blood profile and bone quality of commercial layers. A total of 576 birds were distributed according to a completely randomized experimental design in a 3x4 factorial arrangement (calcium levels of 2.5, 3.1, or 3.7% and clinoptilolite levels of 0.0, 0.15, 0.25, or 0.50%, into 12 treatments with six replicates of eight birds per cage (experimental unit. The experimental period was 112 days. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. Blood uric acid was significantly influenced by the interaction of the evaluated factors. Clinoptilolite levels significantly increased blood calcium levels. There was no effect of dietary calcium levels on any of the evaluated characteristics. It was concluded that feeding layers with up to 0.50% clinoptilolite does not benefit blood uric acid and calcium concentrations and does not affect their bone quality. When layers at the end of the first laying cycle are fed ad libitum and present 119.50g/hen/day average feed intake, 3.1% dietary calcium promotes 3.7g/hen/day calcium intake, which is sufficient to maintain adequate calcium blood levels and bone quality.

  2. Biochemical and functional interactions of a selective kappa opioid agonist with calcium

    Energy Technology Data Exchange (ETDEWEB)

    VonVoigtlander, P.F.; Ochoa, M.C.; Lewis, R.A.

    1987-01-01

    The discovery of the selective kappa opioid receptor agonist, U-50488H, has provided a tool for the study of the mechanisms and function of the kappa receptor-effector. We have investigated the interactions of this compound with calcium in several biochemical and functional studies to assess the involvement of calcium mechanisms in the kappa receptor-linked effector. In rat brain synaptosomes, U-50488H attenuated the uptake of /sup 45/Ca++ induced by K+ (40 mM) depolarization. This effect was concentration-related (U-50488H 10(-5) to 10(-7) M), was apparent in short (8-second) but not longer (1-minute) term incubations, and did not occur in the presence of a non-polarizing concentration (5.6 mM) of K+. Naloxone (10(-7) M) did not block this effect of U-50488H (10(-6) M), and higher concentrations (10(-5) M) alone blocked calcium uptake. We have found that the binding of the depolarizing amino acid analog, kainic acid, is enhanced by CaCl2. U-50488H (10(-4) to 10(-6) M) blocks this enhancement of /sup 3/H-kainic acid binding in vitro and also blocks the in vivo effects of kainic acid. In mice, intravenous injection of kainic acid causes scratching, convulsions, and death, depending on the dose administered. U-50488H blocks all of these effects (ED50 = 4.5 mg/kg for antagonism of convulsions induced by 27.5 mg/kg kainic acid). The convulsions induced by intracerebroventricularly administered kainic acid are also blocked by U-50488H as are those induced by similarly administered Bay K 8644, a calcium channel activator. All of these anticonvulsant effects of U-50488H were antagonized by naltrexone. Together these data indicate that the kappa agonist U-50488H has functionally relevant interactions with depolarization-related Ca++ mechanisms in the central nervous system.

  3. Glass forming ability of calcium aluminosilicate melts

    DEFF Research Database (Denmark)

    Moesgaard, Mette; Yue, Yuanzheng

    2011-01-01

    The glass forming ability (GFA) of two series of calcium aluminosilicate melts is studied by measuring their viscous behavior and crystallization tendency. The first series consists of five compositions on the joining line between the eutectic point of anorthite-wollastonite-tridymite and that of......The glass forming ability (GFA) of two series of calcium aluminosilicate melts is studied by measuring their viscous behavior and crystallization tendency. The first series consists of five compositions on the joining line between the eutectic point of anorthite...... to resist crystallization during reheating. In addition, the fragility index (m) is derived by fitting the viscosity data with the Avramov-Milchev equation. The results show that m is inversely proportional to the glass stability for the two series of melts, implying that m is an indirect measure of GFA....... However, this proportionality is only valid for comparison of the glasses in the same series of compositions. The eutectic composition of anorthite-wollastonite-tridymite is found to exhibit the highest GFA of the melts under investigation....

  4. Calcium signaling in UV-induced damage

    Science.gov (United States)

    Sun, Dan; Zhang, Su-juan; Li, Yuan-yuan; Qu, Ying; Ren, Zhao-Yu

    2007-05-01

    Hepa1-6 cells were irradiated with UV and incubated for varying periods of time. [Ca 2+] i (intracellular calcium concentration) of UV-irradiated cell was measured by ratio fluorescence imaging system. The comet assay was used to determine DNA damage. During the UVB-irradiation, [Ca 2+] i had an ascending tendency from 0.88 J/m2 to 92.4J/m2. Comet assay instant test indicated that when the irradiation dosage was above 0.88J/m2, DNA damage was observed. Even after approximate 2 h of incubation, DNA damage was still not detected by 0.88J/m2 of UVB irradiation. During UVA-irradiation, the elevation of [Ca 2+] i was not dose-dependent in a range of 1200 J/m2-6000J/m2 and DNA damage was not observed by comet assay. These results suggested that several intracellular UV receptors might induce [Ca 2+] i rising by absorption of the UV energy. Just [Ca 2+] i rising can't induce DNA damage certainly, it is very likely that the breakdown of calcium steady state induces DNA damage.u

  5. Aggregation of Phosphoinositides at Phisiological Calcium Concentrations

    Science.gov (United States)

    Kazadi Badiambile, Adolphe; Forstner, Martin B.

    2012-02-01

    Phosphoinositides play a crucial role in many cellular functions such as calcium signaling, endocytosis, exocytosis and the targeting of proteins to specific membrane sites. To maintain functional specificity, it has been suggested that phosphoinositides are spatially organized in ``pools'' in the cellular plasma membrane. A possible mechanism that could induce and regulate such organization of phosphoinositides is their interaction with Ca2+ ions. Understanding the physicochemical mechanism that can regulate membrane structure is a crucial step in the development of adaptive biomimetic membrane systems. Using Langmuir monolayers, we investigated the effect of bivalent calcium and magnesium cations on the surface pressure-area/lipid isotherm of monolayers of phosphatidylinositol (PI), phosphatidylinositol bisphosphate (PIP2) and dioleoylphosphatidylglycerol (DOPG) and dipalmitoylphosphatidylcholine (DPPC). It is found that the decrease of area per lipid, i.e. the increase in aggregation, is dependent on both the lipid's head group charge, the bivalent cation and temperature. However, electrostatics are not sufficient to account for all experimental observations. Thus additional interactions between ions and phosphoinositides need to be considered.

  6. Engineering crystal growth of calcium hydrogenphosphate dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Sikiric, M.; Babic-Ivancic, V. [Institut Rudjer Boskovic, Zagreb (Croatia); Milat, O. [Zagreb Univ. (Croatia). Inst. za Fiziku; Sarig, S.; Fueredi-Milhofer, H. [Hebrew Univ., Jerusalem (Israel). Inst. of Applied Chemistry

    2001-07-01

    The factors underlying calcium hydrogenphosphate dihydrate (CaHPO{sub 4}.2H{sub 2}O, DCPD) interactions with several structurally different additives: glutamic and aspartic acid, sodium citrate, hexaammonium tetrapolyphosphate, calcium phytate and polyaspartic acid were studied. DCPD crystals were prepared under controlled conditions by fast mixing of the anionic and cationic reactant solutions and subsequent growth without further stirring in the course of 24 hours at 37 C. The initial conditions were c(CaCl{sub 2}) = c(Na{sub 2}HPO{sub 4}) = 0.021 mol dm{sup -3}, c(NaCl) = 0.3 mol dm{sup -3}, pH{sub i} 5.5. The respective additive was added to the anionic component prior to pH adjustment. Crystals were characterized by X-ray diffraction, while their morphology was observed by optical and scanning electron microscopy (SEM). The Miller indices of the crystal faces were determined from SEM micrographs, after the orientation of the most prominent face was ascertained by the Weissenberg method. Mechanism of additive-DCPD crystals interaction depends on size and structure of additive molecule, structural fit between organic molecule and the ionic structure of particular crystal face. Small molecules (ions) specifically adsorb on lateral faces by electrostatic interactions, while macromolecules and molecules with hindered structure specifically adsorb on dominant (010) face, for which certain degree of structural fit is necessary. (orig.)

  7. Microhardness studies of nanocrystalline calcium tungstate

    Energy Technology Data Exchange (ETDEWEB)

    Anandakumar, V.M. [Department of Physics, Mahatma Gandhi College, Thiruvananthapuram (India); Khadar, M.A. [Centre for Nanoscience and Nanotechnology and Department of Physics, University of Kerala, Thiruvananthapuram (India)

    2008-02-15

    Nanocrystals of calcium tungstate (CaWO{sub 4}) of three different grain sizes were synthesized through chemical precipitation technique and the grain sizes and crystal structure were determined using the broadening of X-ray diffraction patterns and transmission electron microscopy. The microhardness of compacted pellets of nanocrystalline calcium tungstate (CaWO{sub 4}) with different grain sizes were measured using a Vickers microhardness tester for various applied loads ranging from 0.049 N to 1.96 N. The values of microhardness showed significant reverse indentation size effect at low indentation loads. The microhardness data obtained for samples of different grain sizes showed grain size dependent strengthening obeying normal Hall-Petch relation. The dependence of compacting pressure and annealing temperature on microhardness of the nanostructured sample with grain size of 13 nm were also studied. The samples showed significant increase in microhardness as the compacting pressure and annealing time were increased. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Calcium in edible insects and its use in human nutrition

    Directory of Open Access Journals (Sweden)

    Anna Adámková

    2014-11-01

    Full Text Available Calcium is one of the most problematic substances in human nutrition. Nutrition in the present population is not optimal, because of insufficient consumption of milk and dairy products. Due to the expanding interest of specialists and the general public about entomophagy, as well as increase of the EU interest in this type of food, there is a need to consider the use of edible insects as an alternative source of nutrition. From the perspective of edible insects as a source of calcium, edible insects could be considered as a possible source of calcium for enriching the diet and also as a substitute for people with lactose intolerance and allergies to other categories of foods rich in calcium. Of the six analysed species of edible insect, Bombyx mori had the highest calcium content, almost comparable to semi-skimmed cow's milk. Gryllus assimillis can also be a rich source of calcium as well as other analysed species. The lowest content of calcium was detected in Zophobas morio. Common meat (chicken, beef, pork has lower calcium content comparing with all analysed species of edible insect (Apis mellifera, Bombyx mori, Gryllus assimillis, Locusta migratoria, Tenebrio molitor, Zophobas morio. Therefore, the selected species of edible insect could serve as an alternative source of calcium for people with lactose intolerance and allergies to soy. Phosphorus level in human body is closely related to calcium in the calcium-phosphate metabolism, therefore phosphorus level was detected in these samples too. Bombyx mori had the highest phosphorus content and the lowest content of phosphorus was measured in Zophobas morio samples.

  9. Circulating calcium concentrations, vascular disease and mortality: a systematic review.

    Science.gov (United States)

    Reid, I R; Gamble, G D; Bolland, M J

    2016-06-01

    Associations between serum calcium and vascular disease have been reported, but the consistency of these findings is unknown. We conducted a systematic review to determine whether circulating calcium concentrations are associated with risks of cardiovascular disease and death in normocalcaemic populations. We conducted PubMed searches up to 18 December 2014 and scrutinized reference lists of papers. Eligible studies related serum calcium to mortality or cardiovascular events in humans. A follow-up of at least one year was required for longitudinal studies. Studies in populations selected on the basis of renal disease or abnormal serum calcium were excluded. Two investigators performed independent data extraction. The results were tabulated and, where possible, meta-analysed. Five of 11 studies reported a statistically significant positive association between serum calcium and mortality. Meta-analysis of eight of these studies showed a hazard ratio of death of 1.13 (1.09, 1.18) per standard deviation of serum calcium. Eight of 13 studies reported a statistically significant positive association between serum calcium and cardiovascular disease. Meta-analysis of eight studies showed a hazard ratio of cardiovascular disease of 1.08 (1.04, 1.13) per standard deviation of serum calcium. For two studies reporting odds ratios, the pooled odds ratio per standard deviation was 1.22 (1.11, 1.32). When hazard ratios adjusted for cardiovascular risk factors were meta-analysed, the pooled hazard ratio was 1.04 (1.01, 1.08). Other studies demonstrated associations between serum calcium and stroke and between serum calcium and direct measurements of arterial disease and calcification. These observational data indicate that serum calcium is associated with vascular disease and death, but they cannot determine causality. PMID:26749423

  10. Asante Calcium Green and Asante Calcium Red--novel calcium indicators for two-photon fluorescence lifetime imaging.

    Directory of Open Access Journals (Sweden)

    Karolina Jahn

    Full Text Available For a comprehensive understanding of cellular processes and potential dysfunctions therein, an analysis of the ubiquitous intracellular second messenger calcium is of particular interest. This study examined the suitability of the novel Ca2+-sensitive fluorescent dyes Asante Calcium Red (ACR and Asante Calcium Green (ACG for two-photon (2P-excited time-resolved fluorescence measurements. Both dyes displayed sufficient 2P fluorescence excitation in a range of 720-900 nm. In vitro, ACR and ACG exhibited a biexponential fluorescence decay behavior and the two decay time components in the ns-range could be attributed to the Ca(2+-free and Ca(2+-bound dye species. The amplitude-weighted average fluorescence decay time changed in a Ca(2+-dependent way, unraveling in vitro dissociation constants K(D of 114 nM and 15 nM for ACR and ACG, respectively. In the presence of bovine serum albumin, the absorption and steady-state fluorescence behavior of ACR was altered and its biexponential fluorescence decay showed about 5-times longer decay time components indicating dye-protein interactions. Since no ester derivative of ACG was commercially available, only ACR was evaluated for 2P-excited fluorescence lifetime imaging microscopy (2P-FLIM in living cells of American cockroach salivary glands. In living cells, ACR also exhibited a biexponential fluorescence decay with clearly resolvable short (0.56 ns and long (2.44 ns decay time components attributable to the Ca(2+-free and Ca(2+-bound ACR species. From the amplitude-weighted average fluorescence decay times, an in situ K(D of 180 nM was determined. Thus, quantitative [Ca(2+]i recordings were realized, unraveling a reversible dopamine-induced [Ca(2+]i elevation from 21 nM to 590 nM in salivary duct cells. It was concluded that ACR is a promising new Ca(2+ indicator dye for 2P-FLIM recordings applicable in diverse biological systems.

  11. Serum calcium level is related to both intima-media thickness and carotid atherosclerosis: a neglect risk factor in obese/overweight subjects

    Directory of Open Access Journals (Sweden)

    Montalcini Tiziana

    2012-06-01

    Full Text Available Abstract Background Experimental studies suggested that high serum calcium may be important in the pathogenesis of vascular diseases. Since calcium seems to affect specifically the cerebrovascular district, aim of this study was to determine the relation between serum calcium levels, within normal range, and subclinical atherosclerosis in the carotid arteries, in a population of obese/overweight subjects. Methods In our retrospective study we included 472 subjects (59% female with body mass index equal to or more than 25 kg/m2. They underwent a physical examination, a biochemical assessment (including calcium evaluation and a B-mode ultrasonography of the extracranial carotid arteries to detect carotid atherosclerosis presence and to measure intima-media thickness. Results Mean age of the population was 50 ±12 years. Prevalence of the Carotid atherosclerosis was 40%. Mean carotid intima-media thickness was 0,66 ± 0,18 mm. The univariate and multivariate analysis showed an association between calcium and carotid intima-media thickness (p = 0,035. We divided the population in serum calcium tertiles. We found an higher carotid atherosclerosis prevalence in the III tertile in comparison to that of the I tertile (p = 0,039. Conclusions In this study we found a positive relation between serum calcium levels, within normal range, and subclinical atherosclerosis in the carotid arteries, in a population of obese/overweight subjects. It is important to consider the impact of the serum calcium levels in the overall risk assessment of patients, at least in obese subjects.

  12. Localization and pharmacological characterization of voltage dependent calcium channels in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Timmermann, D B; Lund, Trine Meldgaard; Belhage, B;

    2001-01-01

    The physiological significance and subcellular distribution of voltage dependent calcium channels was defined using calcium channel blockers to inhibit potassium induced rises in cytosolic calcium concentration in cultured mouse neocortical neurons. The cytosolic calcium concentration was measured...... using the fluorescent calcium chelator fura-2. The types of calcium channels present at the synaptic terminal were determined by the inhibitory action of calcium channel blockers on potassium-induced [3H]GABA release in the same cell preparation. L-, N-, P-, Q- and R-/T-type voltage dependent calcium...... most important voltage dependent calcium channel in all parts of the neuron. After treatment with thapsigargin the increase in cytosolic calcium was halved, indicating that calcium release from thapsigargin sensitive intracellular calcium stores is an important component of the potassium induced rise...

  13. Treating High Blood Pressure: Is a Calcium Channel Blocker Drug Right for You?

    Science.gov (United States)

    ... Blood Pressure: Is a Calcium Channel Blocker Drug Right for You? What are calcium channel blockers? Calcium ... talk with your doctor about which drugs are right for you. If your blood pressure is slightly ...

  14. Calcium Imaging of Pheromone Responses in the Insect Antennal Lobe

    OpenAIRE

    Kim, Susy M.; Wang, Jing W.

    2013-01-01

    Calcium imaging is a powerful technique that permits the visual monitoring of neural responses to pheromones and other odors in large ensembles of neurons. Here, we describe a method that permits the monitoring of Drosophila antennal lobe responses to odors using the genetically encoded calcium monitor GCaMP.

  15. Calcium binding to cardiac myocytes protected from proteolytic enzyme activity.

    Science.gov (United States)

    Bailey, L E; Fawzi, A B

    1985-04-17

    Excitation-contraction coupling in cardiac muscle is dependent on extracellular calcium and calcium bound to the surface of the myocardial cell. In this study, we examined the physical characteristics of calcium binding to adult guinea pig ventricular myocytes disaggregated mechanically in oxygenated tissue culture medium containing a proteinase inhibitor (aprotinin), and separated from cellular debris by Cytodex beads. Cells prepared in this manner excluded Trypan blue and showed no evidence of spontaneous contraction or contracture. Scatchard plots of calcium binding determined by continuous flow equilibrium dialysis revealed a high-affinity, low-capacity pool, Ka = 65 X 10(3) M-1 and Bt = 1.3 nmol X mg-1 and a low-affinity, high-capacity pool, Ka = 141 M-1 and Bt = 138 nmol X mg-1. The low-affinity pool was not detectable after lanthanum, trypsin or collagenase treatment or in cells prepared without aprotinin in the isolation medium. Both neuraminidase and phospholipase C reduced Bt of the low-affinity pool by one half, but only neuraminidase affected the affinity constant of this pool. Ka was increased to 516.7 M-1, similar to the apparent affinity constant for calcium binding estimated from dP/dtmax measured at several extracellular calcium concentrations (470 M-1). The results suggest that calcium bound to sarcolemmal phospholipids represents the superficial calcium involved in excitation-contraction coupling in the heart.

  16. Calcium score of small coronary calcifications on multidetector computed tomography

    DEFF Research Database (Denmark)

    Groen, J M; Kofoed, K F; Zacho, M;

    2013-01-01

    Multi detector computed tomography (MDCT) underestimates the coronary calcium score as compared to electron beam tomography (EBT). Therefore clinical risk stratification based on MDCT calcium scoring may be inaccurate. The aim of this study was to assess the feasibility of a new phantom which ena...

  17. Mitochondrial DNA mutations affect calcium handling in differentiated neurons.

    NARCIS (Netherlands)

    Trevelyan, A.J.; Kirby, D.M.; Smulders-Srinivasan, T.K.; Nooteboom, M.; Acin-Perez, R.; Enriquez, J.A.; Whittington, M.A.; Lightowlers, R.N.; Turnbull, D.M.

    2010-01-01

    Mutations in the mitochondrial genome are associated with a wide range of neurological symptoms, but many aspects of the basic neuronal pathology are not understood. One candidate mechanism, given the well-established role of mitochondria in calcium buffering, is a deficit in neuronal calcium homoeo

  18. Control of calcium carbonate precipitation in anaerobic reactors.

    NARCIS (Netherlands)

    Langerak, van E.P.A.

    1998-01-01

    Anaerobic treatment of waste waters with a high calcium content may lead to excessive precipitation of calcium carbonate. So far, no proper methods were available to predict or reduce the extent of precipitation in an anaerobic treatment system. Moreover, it also was not clear to what extent precipi

  19. Impact of iterative reconstruction on CT coronary calcium quantification

    DEFF Research Database (Denmark)

    Kurata, Akira; Dharampal, Anoeshka; Dedic, Admir;

    2013-01-01

    We evaluated the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on the coronary artery calcium (CAC) score by computed tomography (CT).......We evaluated the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on the coronary artery calcium (CAC) score by computed tomography (CT)....

  20. Role of Calcium Hydroxide in Endodontics: A Review

    OpenAIRE

    Arun A; Sangameshwar Sajjanshetty; Deepak Jain; Saujanya KP; Mohammed Mustafa; Laxmi Uppin; Mahnoor Kadri

    2012-01-01

    Calcium hydroxide is a multipurpose agent, and there have been an increasing number of indications for its use in endodontics. Some of its indications include inter-appointment intracanal medicaments, endodontic sealers, pulp capping agents, apexification, pulpotomy and weeping canals. The purpose of this article is to review the properties, advantages, disadvantages and various indications for the use of calcium hydroxide in endodontics.

  1. Calcium electrotransfer for termination of transgene expression in muscle

    DEFF Research Database (Denmark)

    Hojman, Pernille; Spanggaard, Iben; Olsen, Caroline Holkman;

    2011-01-01

    Gene electrotransfer is expanding in clinical use, thus we have searched for an emergency procedure to stop transgene expression in case of serious adverse events. Calcium is cytotoxic at high intracellular levels, so we tested effects of calcium electrotransfer on transgene expression in muscle....

  2. Vitamin D deficiency and calcium absorption during childhood

    Science.gov (United States)

    Although the importance of providing adequate calcium and vitamin D during childhood and adolescent growth is well known, there remain important gaps in our understanding regarding the process of calcium absorption and utilization in childhood. Certain time periods in development appear to be critic...

  3. Differential mitochondrial calcium responses in different cell types detected with a mitochondrial calcium fluorescent indicator, mito-GCaMP2

    Institute of Scientific and Technical Information of China (English)

    Min Chen; Yanru Wang; Tingting Hou; Huiliang Zhang; Aijuan Qu; Xianhua Wang

    2011-01-01

    Mitochondrial calcium plays a crucial role in mitochondriai metabolism,cell calcium handling,and cell death.However,some mechanisms concerning mitochondrial calcium regulation are still unknown,especially how mitochondrial calcium couples with cytosolic calcium.In this work,we constructed a novel mitochondrial calcium fluorescent indicator (mito-GCaMP2) by genetic manipulation.Mito-GCaMP2 was imported into mitochondria with high efficiency and the fluorescent signals co-localized with that of tetramethyl rhodamine methyl ester,a mitochondrial membrane potential indicator.The mitochondrial inhibitors specifically decreased the signals of mito-GCaMP2.The apparent Kd of mito-GCaMP2 was 195.0 nmol/L at pH 8.0 in adult rat cardiomyocytes.Furthermore,we observed that mito-GCaMP2 preferred the alkaline pH surrounding of mitochondria.In HeLa cells,we found that mitochondrial calcium ([Ca2+]mito)responded to the changes of cytosolic calcium ([Ca2+]cyto)induced by histamine or thapasigargin.Moreover,external Ca2+ (100 μmol/L) directly induced an increase of [Ca2+]mito in permeabilized HeLa cells.However,in rat cardiomyocytes [Ca2+]mito did not respond to cytosolic calcium transients stimulated by electric pacing or caffeine.In permeabilized cardiomyocytes,600 nmol/L free Ca2+ repeatedly increased the fluorescent signals of mito-GCaMP2,which excluded the possibility that mito-GCaMP2 lost its function in cardiomyocytes mitochondria.These results showed that the response of mitochondrial calcium is diverse in different cell lineages and suggested that mitochondria in cardiomyocytes may have a special defense mechanism to control calcium flux.

  4. Transformation mechanism of amorphous calcium carbonate into calcite in the sea urchin larval spicule.

    Science.gov (United States)

    Politi, Yael; Metzler, Rebecca A; Abrecht, Mike; Gilbert, Benjamin; Wilt, Fred H; Sagi, Irit; Addadi, Lia; Weiner, Steve; Gilbert, P U P A; Gilbert, Pupa

    2008-11-11

    Sea urchin larval spicules transform amorphous calcium carbonate (ACC) into calcite single crystals. The mechanism of transformation is enigmatic: the transforming spicule displays both amorphous and crystalline properties, with no defined crystallization front. Here, we use X-ray photoelectron emission spectromicroscopy with probing size of 40-200 nm. We resolve 3 distinct mineral phases: An initial short-lived, presumably hydrated ACC phase, followed by an intermediate transient form of ACC, and finally the biogenic crystalline calcite phase. The amorphous and crystalline phases are juxtaposed, often appearing in adjacent sites at a scale of tens of nanometers. We propose that the amorphous-crystal transformation propagates in a tortuous path through preexisting 40- to 100-nm amorphous units, via a secondary nucleation mechanism.

  5. Papillary and Nonpapillary Calcium Oxalate Monohydrate Renal Calculi: Comparative Study of Etiologic Factors

    Directory of Open Access Journals (Sweden)

    Enrique Pieras

    2006-01-01

    Full Text Available Calcium oxalate monohydrate (COM renal calculi can be classified into two groups: papillary and nonpapillary. In this paper, a comparative study between etiologic factors of COM papillary and nonpapillary calculi is performed. The study included 40 patients with COM renal calculi. The urine of these individuals was analyzed. Case history, lifestyle, and dietetic habits were obtained.No significant differences between urinary biochemical data of both groups were observed; 50% of COM papillary stone formers and 40% of COM nonpapillary stone formers had urolithiasis family history. A low consumption of phytate-rich products was observed for both groups. A relationship between profession with occupational exposure to cytotoxic products and COM papillary renal lithiasis was detected.The results suggest that COM papillary calculi would be associated to papillary epithelium alterations together with a crystallization inhibitors deficit, whereas COM nonpapillary calculi would be associated to the presence of heterogeneous nucleants and a crystallization inhibitors deficit.

  6. Modulation of intracellular calcium levels by calcium lactate affects colon cancer cell motility through calcium-dependent calpain.

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    Pasupathi Sundaramoorthy

    Full Text Available Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca2+ supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca2+ bound lactate (CaLa, its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca2+ (iCa2+ levels for a prolonged period of time. Ca2+ influx induced cleavage of FAK into an N-terminal FAK (FERM domain in a dose-dependent manner. Phosphorylated FAK (p-FAK was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca2+ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca2+ supplementation to patient undergoing treatment for metastatic cancer.

  7. Both serum 25-hydroxyvitamin D and calcium levels may increase the risk of incident prostate cancer in Caribbean men of African ancestry

    OpenAIRE

    Jackson, Maria D; Marshall K. Tulloch-Reid; Lindsay, Carole M; Smith, Garrett; Bennett, Franklyn I.; McFarlane-Anderson, Norma; Aiken, William; Coard, Kathleen C. M.

    2015-01-01

    Circulating 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with both higher and lower risk of prostate cancer (PCa), whereas elevated levels of circulating calcium has been related to higher risks. However, there are few studies that account for effects of both calcium and 25(OH)D concentrations on incident PCa in a black population. We examined these relationships in a case–control study of men 40–80 years old with newly diagnosed, histologically confirmed PCa in Jamaica, ...

  8. Calcium pump kinetics determined in single erythrocyte ghosts by microphotolysis and confocal imaging.

    OpenAIRE

    Kubitscheck, U; Pratsch, L; Passow, H; Peters, R.

    1995-01-01

    The activity of the plasma membrane calcium pump was measured in single cells. Human red blood cell ghosts were loaded with a fluorescent calcium indicator and either caged calcium and ATP (protocol A) or caged ATP and calcium (protocol B). In a suitably modified laser scanning microscope either calcium or ATP were released by a short UV light pulse. The time-dependent fluorescence intensity of the calcium indicator was then followed in single ghosts by repetitive confocal imaging. The fluore...

  9. Pharmacokinetic interactions with calcium channel antagonists (Part I).

    Science.gov (United States)

    Schlanz, K D; Myre, S A; Bottorff, M B

    1991-11-01

    Calcium channel antagonists are a diverse class of drugs widely used in combination with other therapeutic agents. The potential exists for many clinically significant pharmacokinetic interactions between these and other concurrently administered drugs. The mechanisms of calcium channel antagonist-induced changes in drug metabolism include altered hepatic blood flow and impaired hepatic enzyme metabolising activity. Increases in serum concentrations and/or reductions in clearance have been reported for several drugs used with a number of calcium channel antagonists. A number of reports and studies of calcium channel antagonist interactions have yielded contradictory results and the clinical significance of pharmacokinetic changes seen with these agents is ill-defined. The first part of this article deals with interactions between calcium antagonists and marker compounds, theophylline, midazolam, lithium, doxorubicin, oral hypoglycaemics and cardiac drugs. PMID:1773549

  10. Studies on calcium oxalate monohydrate crystallization: influence of inhibitors.

    Science.gov (United States)

    Grases, F; Kroupa, M; Costa-Bauzá, A

    1994-01-01

    A simple model to study calcium oxalate monohydrate (COM) crystallization on different substrates is presented and the action of different potential inhibitors is evaluated and discussed. COM heterogeneous nucleation was assayed on solid surfaces as calcium phosphate, mixtures of mucin with calcium phosphate, and wax. In the presence of a non-protected non-renewed solid surface in contact with normal urine, COM crystal formation could be detected at short intervals (3 h). The most active heterogeneous nucleation capacity corresponded to calcium phosphate. In the presence of 10% mucin, owing to the renewal of the surface layer no COM crystal were detected on the pellet's surface. The study of citrate and pentosan polysulphate (a semisynthetic polysaccharide) on COM heterogeneous nucleation demonstrated some important inhibitory effects when concentration increased and time decreased. Maximum effects were selectively manifested on calcium phosphate surfaces. Only phytic acid at adequate concentration exhibited a total inhibitory capacity of COM formation, even during longer intervals (15 h). PMID:7521089

  11. Calcium Signaling and Meiotic Exit at Fertilization in Xenopus Egg

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    Alexander A. Tokmakov

    2014-10-01

    Full Text Available Calcium is a universal messenger that mediates egg activation at fertilization in all sexually reproducing species studied. However, signaling pathways leading to calcium generation and the mechanisms of calcium-induced exit from meiotic arrest vary substantially among species. Here, we review the pathways of calcium signaling and the mechanisms of meiotic exit at fertilization in the eggs of the established developmental model, African clawed frog, Xenopus laevis. We also discuss calcium involvement in the early fertilization-induced events in Xenopus egg, such as membrane depolarization, the increase in intracellular pH, cortical granule exocytosis, cortical contraction, contraction wave, cortical rotation, reformation of the nuclear envelope, sperm chromatin decondensation and sister chromatid segregation.

  12. Conversion coatings prepared or treated with calcium hydroxide solutions

    Science.gov (United States)

    Minevski, Zoran (Inventor); Clarke, Eric (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  13. Pyrochemical recovery of plutonium from calcium fluoride reduction slag

    Science.gov (United States)

    Christensen, D.C.

    A pyrochemical method of recovering finely dispersed plutonium metal from calcium fluoride reduction slag is claimed. The plutonium-bearing slag is crushed and melted in the presence of at least an equimolar amount of calcium chloride and a few percent metallic calcium. The calcium chloride reduces the melting point and thereby decreases the viscosity of the molten mixture. The calcium reduces any oxidized plutonium in the mixture and also causes the dispersed plutonium metal to coalesce and settle out as a separate metallic phase at the bottom of the reaction vessel. Upon cooling the mixture to room temperature, the solid plutonium can be cleanly separated from the overlying solid slag, with an average recovery yield on the order of 96 percent.

  14. Calcium regulation of oxidative phosphorylation in rat skeletal muscle mitochondria.

    Science.gov (United States)

    Kavanagh, N I; Ainscow, E K; Brand, M D

    2000-02-24

    Activation of oxidative phosphorylation by physiological levels of calcium in mitochondria from rat skeletal muscle was analysed using top-down elasticity and regulation analysis. Oxidative phosphorylation was conceptually divided into three subsystems (substrate oxidation, proton leak and phosphorylation) connected by the membrane potential or the protonmotive force. Calcium directly activated the phosphorylation subsystem and (with sub-saturating 2-oxoglutarate) the substrate oxidation subsystem but had no effect on the proton leak kinetics. The response of mitochondria respiring on 2-oxoglutarate at two physiological concentrations of free calcium was quantified using control and regulation analysis. The partial integrated response coefficients showed that direct stimulation of substrate oxidation contributed 86% of the effect of calcium on state 3 oxygen consumption, and direct activation of the phosphorylation reactions caused 37% of the increase in phosphorylation flux. Calcium directly activated phosphorylation more strongly than substrate oxidation (78% compared to 45%) to achieve homeostasis of mitochondrial membrane potential during large increases in flux.

  15. Influence of calcium carbonate on extraction yield and quality of extra virgin oil from olive (Olea europaea L. cv. Coratina).

    Science.gov (United States)

    Squeo, G; Silletti, R; Summo, C; Paradiso, V M; Pasqualone, A; Caponio, F

    2016-10-15

    The aim of the research was to evaluate the effect of calcium carbonate (1%, 2%, and 4% of addition) at two different particle sizes (2.7μm and 5.7μm), added at the beginning of the malaxation phase, on both the extraction yield and the quality of oil obtained from Coratina olives at different ripening index. The results showed that calcium carbonate significantly increased the extraction yield of olive oil, more than affecting chemical indices. In particular, for less ripened olives, 1-2% of larger particle size calcium carbonate addiction determined a significant increase of the extraction effectiveness, ranging from 4.0 to 4.9%, while more ripened olives required higher amounts of coadjuvant (2-4% when using the larger particle size and 4% when using the smaller one), with a significant increase of the extraction yield up to 5%. Moreover, an increase of pungent perception was observed in some cases when adding calcium carbonate to more ripened olives.

  16. Calcium-binding capacity of centrin2 is required for linear POC5 assembly but not for nucleotide excision repair.

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    Tiago J Dantas

    Full Text Available Centrosomes, the principal microtubule-organising centres in animal cells, contain centrins, small, conserved calcium-binding proteins unique to eukaryotes. Centrin2 binds to xeroderma pigmentosum group C protein (XPC, stabilising it, and its presence slightly increases nucleotide excision repair (NER activity in vitro. In previous work, we deleted all three centrin isoforms present in chicken DT40 cells and observed delayed repair of UV-induced DNA lesions, but no centrosome abnormalities. Here, we explore how centrin2 controls NER. In the centrin null cells, we expressed centrin2 mutants that cannot bind calcium or that lack sites for phosphorylation by regulatory kinases. Expression of any of these mutants restored the UV sensitivity of centrin null cells to normal as effectively as expression of wild-type centrin. However, calcium-binding-deficient and T118A mutants showed greatly compromised localisation to centrosomes. XPC recruitment to laser-induced UV-like lesions was only slightly slower in centrin-deficient cells than in controls, and levels of XPC and its partner HRAD23B were unaffected by centrin deficiency. Interestingly, we found that overexpression of the centrin interactor POC5 leads to the assembly of linear, centrin-dependent structures that recruit other centrosomal proteins such as PCM-1 and NEDD1. Together, these observations suggest that assembly of centrins into complex structures requires calcium binding capacity, but that such assembly is not required for centrin activity in NER.

  17. Effect of Combined Use of Calcium and Vitamin B6 on Premenstrual Syndrome Symptoms: a Randomized Clinical Trial

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    Seyedeh Zahra Masoumi

    2016-03-01

    Full Text Available Introduction: Premenstrual syndrome is one of the most common disorders in women, which includes a group of psychological and physical symptoms. The aim of this study was to examine the impact of combined use of calcium and vitamin B6 on premenstrual syndrome symptoms. Methods: This double blind randomized controlled was carried out on 76 students of Hamadan University of Medical Sciences. Students were randomly allocated to two groups. (38 people in each group. Student in intervention groups received calcium tablet (500mg and vitamin B6 (40 mg and student in intervention groups received only vitamin B6 twice a day for two consecutive months. The symptoms were assessed by Beck depression inventory (BDI and daily symptom records (DSR questionnaires. Analyses were carried out by test-retest method, Chi-square, Mann-Whitney, Independent t-test, and paired t-test using SPSS software ver.13. Results: The result showed that although the severity of symptoms decreased in both groups, but this reduction was more significant in the combined calcium and vitamin B6 group. Conclusion: According to the result, using of combination of calcium and vitamin B6 leads to better controlling of the premenstrual syndrome symptoms. Therefore it is recommended for women who suffer from these syndromes.

  18. Influence of calcium carbonate on extraction yield and quality of extra virgin oil from olive (Olea europaea L. cv. Coratina).

    Science.gov (United States)

    Squeo, G; Silletti, R; Summo, C; Paradiso, V M; Pasqualone, A; Caponio, F

    2016-10-15

    The aim of the research was to evaluate the effect of calcium carbonate (1%, 2%, and 4% of addition) at two different particle sizes (2.7μm and 5.7μm), added at the beginning of the malaxation phase, on both the extraction yield and the quality of oil obtained from Coratina olives at different ripening index. The results showed that calcium carbonate significantly increased the extraction yield of olive oil, more than affecting chemical indices. In particular, for less ripened olives, 1-2% of larger particle size calcium carbonate addiction determined a significant increase of the extraction effectiveness, ranging from 4.0 to 4.9%, while more ripened olives required higher amounts of coadjuvant (2-4% when using the larger particle size and 4% when using the smaller one), with a significant increase of the extraction yield up to 5%. Moreover, an increase of pungent perception was observed in some cases when adding calcium carbonate to more ripened olives. PMID:27173535

  19. Calcium in Mercury's Exosphere: Modeling MESSENGER Data

    Science.gov (United States)

    Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee; Vervack, Ronald J.; Sarantos, Menelaos; Sprague, Ann L.

    2011-01-01

    Mercury is surrounded by a surface-bounded exosphere comprised of atomic species including hydrogen, sodium, potassium, calcium, magnesium, and likely oxygen. Because it is collisionless. the exosphere's composition represents a balance of the active source and loss processes. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface. Space ENvironment. GEochemistry. and Ranging (MESSENGER) spacecraft has made high spatial-resolution observations of sodium, calcium, and magnesium near Mercury's surface and in the extended, anti-sunward direction. The most striking feature of these data has been the substantial differences in the spatial distribution of each species, Our modeling demonstrates that these differences cannot be due to post-ejection dynamics such as differences in photo-ionization rate and radiation pressure. but instead point to differences in the source mechanisms and regions on the surface from which each is ejected. The observations of calcium have revealed a strong dawn/dusk asymmetry. with the abundance over the dawn hemisphere significantly greater than over the dusk. To understand this asymmetry, we use a Monte Carlo model of Mercury's exosphere that we developed to track the motions of exospheric neutrals under the influence of gravity and radiation pressure. Ca atoms can be ejected directly from the surface or produced in a molecular exosphere (e.g., one consisting of CaO). Particles are removed from the system if they stick to the surface or escape from the model region of interest (within 15 Mercury radii). Photoionization reduces the final weighting given to each particle when simulating the Ca radiance. Preliminary results suggest a high temperature ( I-2x 10(exp 4) K) source of atomic Ca concentrated over the dawn hemisphere. The high temperature is consistent with the dissociation of CaO in a near-surface exosphere with scale height <= 100 km, which imparts 2 eV to the freshly produced Ca atom. This

  20. Calcium in Mercury's Exosphere: Modeling MESSENGER Data

    Science.gov (United States)

    Burger, M. H.; Killen, R. M.; McClintock, W. E.; Merkel, A. W.; Vervack, R. J.; Sarantos, M.; Sprague, A. L.

    2011-12-01

    Mercury is surrounded by a surface-bounded exosphere known to contain hydrogen, sodium, potassium, calcium, and magnesium. Because the exosphere is collisionless, its composition represents a balance of active source and loss processes. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has made high-spatial-resolution observations of sodium, calcium, and magnesium near Mercury's surface and in the extended, anti-sunward direction. The most striking feature of these data is the substantial differences among species, which was detected during three close flybys of the planet and has been persistantly present during MESSENGER's orbital phase. Our modeling demonstrates that these differences are not because of post-ejection dynamics such as differences in photo-ionization rate and radiation pressure, but rather result from differences in the source mechanisms and regions on the surface from which each species is ejected. The observations of calcium have revealed a strong dawn/dusk asymmetry, with the abundance over the dawn hemisphere substantially greater than that on the dusk side. To understand this asymmetry, we use a Monte Carlo model of Mercury's exosphere that we developed to track the motions of exospheric neutrals under the influence of gravity and radiation pressure. In this model, Ca atoms can be ejected directly from the surface or produced by ejection of CaO followed by dissociation to produce Ca and O. Particles are removed from the system if they stick to the surface or escape from the model region of interest (within 15 Mercury radii). Photoionization reduces the final weighting given to each particle when simulating the Ca radiance. Data from the flybys are consistent with a high temperature (~1-2 x 104 K) source of atomic Ca concentrated over the dawn hemisphere. Such a high temperature resutls from dissociation of CaO in a near