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.

Calcium absorption

International Nuclear Information System (INIS)

Carlmark, B.; Reizenstein, P.; Dudley, R.A.

1976-01-01

The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

Radioisotope 45Ca labeling four calcium chemical compounds and tracing calcium bioavailability

International Nuclear Information System (INIS)

Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen

2004-01-01

Objective: To build up a new method of the radioisotope 45 Ca labeling four calcium chemical compounds, observe and tracing bioavailability change of calcium labeled with radioisotope 45 Ca. Methods: The calcium gluconate (Ca-Glu), calcium citrate (Ca-Cit), calcium carbonate (Ca-Car) and calcium L-threonate (Ca-Thr)were labeled by radioisotope 45 Ca. Four calcium chemical compounds of 45 Ca labeling were used of calcium content 200 mg/kg in the rats and measure the absorption content and bioavailability of calcium in tissue of heart, lever spleen, stomach, kidney, brain, intestine, whole blood, urine, faeces. Results: 1) Radioisotope 45 Ca labeling calcium chemical compound has high radio intensity, more steady standard curve and recover rate. 2) The absorption of organic calcium chemical compounds is higher than the inorganic calcium chemical compound in the study of calcium bioavailability. Conclusion: The method of tracing with radioisotope 45 Ca labeling calcium chemical compounds has the characteristic of the sensitive, objective, accurate and steady in the study of calcium bioavailability

The impact of calcium assay change on a local adjusted calcium equation.

Science.gov (United States)

Davies, Sarah L; Hill, Charlotte; Bailey, Lisa M; Davison, Andrew S; Milan, Anna M

2016-03-01

Deriving and validating local adjusted calcium equations is important for ensuring appropriate calcium status classification. We investigated the impact on our local adjusted calcium equation of a change in calcium method by the manufacturer from cresolphthalein complexone to NM-BAPTA. Calcium and albumin results from general practice requests were extracted from the Laboratory Information Management system for a three-month period. Results for which there was evidence of disturbance in calcium homeostasis were excluded leaving 13,482 sets of results for analysis. The adjusted calcium equation was derived following least squares regression analysis of total calcium on albumin and normalized to the mean calcium concentration of the data-set. The revised equation (NM-BAPTA calcium method) was compared with the previous equation (cresolphthalein complexone calcium method). The switch in calcium assay resulted in a small change in the adjusted calcium equation but was not considered to be clinically significant. The calcium reference interval differed from that proposed by Pathology Harmony in the UK. Local adjusted calcium equations should be re-assessed following changes in the calcium method. A locally derived reference interval may differ from the consensus harmonized reference interval. © The Author(s) 2015.

48 CFR 6101.54 - Alternative dispute resolution [Rule 54].

Science.gov (United States)

2010-10-01

... CONTRACT APPEALS, GENERAL SERVICES ADMINISTRATION CONTRACT DISPUTE CASES 6101.54 Alternative dispute resolution [Rule 54]. (a) Availability of alternative dispute resolution (ADR) procedures at the Board. The... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Alternative dispute...

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 ...

Calcium waves.

Science.gov (United States)

Jaffe, Lionel F

2008-04-12

Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

Absorbability of calcium from calcium-bound phosphoryl oligosaccharides in comparison with that from various calcium compounds in the rat ligated jejunum loop.

Science.gov (United States)

To-o, Kenji; Kamasaka, Hiroshi; Nishimura, Takahisa; Kuriki, Takashi; Saeki, Shigeru; Nakabou, Yukihiro

2003-08-01

Calcium-bound phosphoryl oligosaccharides (POs-Ca) were prepared from potato starch. Their solubility and in situ absorbability as a calcium source were investigated by comparing with the soluble calcium compounds, calcium chloride and calcium lactate, or insoluble calcium compounds, calcium carbonate and dibasic calcium phosphate. The solubility of POs-Ca was as high as that of calcium chloride and about 3-fold higher than that of calcium lactate. An in situ experiment showed that the intestinal calcium absorption rate of POs-Ca was almost comparable with that of the soluble calcium compounds, and was significantly higher (pcalcium groups. Moreover, the total absorption rate of a 1:1 mixture of the calcium from POs-Ca and a whey mineral complex (WMC) was significantly higher (psoluble calcium source with relatively high absorption in the intestinal tract.

Get Enough Calcium

Science.gov (United States)

... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... women, don't get enough calcium. How much calcium do I need every day? Women: If you ...

The Effects of Dietary Calcium and/or Iron Deficiency upon Murine Intestinal Calcium Binding Protein Activity and Calcium Absorption

OpenAIRE

McDonald, Catherine M.

1980-01-01

Iron deficiency has been shown to impair calcium absorption, leading to decreased bone mass. Vitamin D3-dependent calcium binding protein (CaBP) has been demonstrated to be necessary for the active transport of calcium in the intestine of numerous species. Iron deficiency might affect the activity of the calcium binding protein. Four experimental diets were formulated as follows: Diet 1, iron adequate, calcium adequate; Diet 2, iron deficient, calcium adequate; Diet 3, iron adequate, calci...

Effects of diphosphonate on kidney calcium content and duodenal absorption of 45calcium

International Nuclear Information System (INIS)

Goulding, A.; Cameron, V.

1978-01-01

In rats the relationships between EHDP-induced changes in serum calcium concentration, kidney calcium content and duodenal transport of 45 calcium were studied. Body weights and kidney weights were similar in all groups. EHDP administration was associated with an increase in serum calcium concentration and kidney calcium content, and a decrease in duodenal 45 calcium transport. In the EHDP-treated rats, there was a significant negative correlation between kidney calcium concentration and duodenal 45 calcium transport but no correlation between either kidney calcium content and serum calcium concentration (r = 0.116) or between serum calcium concentration and duodenal 45 calcium transport (r = 0.02). Further experiments will be needed to determine whether the demonstrated increase in kidney calcium content induced by EHDP administration was the cause of, or was secondary to, inhibition of 1, 25(OH) 2 D 3 synthesis. (orig./AJ) [de

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

International Nuclear Information System (INIS)

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

1988-01-01

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 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

Impaired control of L-type voltage-dependent calcium channels in experimental hypertension

Czech Academy of Sciences Publication Activity Database

Pintérová, Mária; Líšková, Silvia; Dobešová, Zdenka; Behuliak, M.; Kuneš, Jaroslav; Zicha, Josef

2009-01-01

Roč. 58, Suppl.2 (2009), S43-S54 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA305/08/0139; GA ČR(CZ) GA305/09/0336; GA AV ČR(CZ) IAA500110902; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : calcium -activated K+ and Cl- channels * vasoactive systems * EDCF Subject RIV: ED - Physiology Impact factor: 1.430, year: 2009

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

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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.

Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

International Nuclear Information System (INIS)

Jepson, B.E.; Shockey, G.C.

1984-01-01

The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon( 44 Ca/ 40 Ca) = 11 x 10 -4 and epsilon( 48 Ca/ 40 Ca) = 18 x 10 -4 . The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10 -4 . 20 references, 2 figures

Calcium

Science.gov (United States)

... You can get decent amounts of calcium from baked beans, navy beans, white beans, and others. Canned fish. You're in luck if you like sardines and canned salmon with bones. Almond milk. Working Calcium Into Your ...

Influence of dietary calcium on bone calcium utilization

International Nuclear Information System (INIS)

Farmer, M.; Roland, D.A. Sr.; Clark, A.J.

1986-01-01

In Experiment 1, 10 microCi 45 Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of 45 Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and 45 Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on 45 Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and 45 Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly

Physicochemical Approach to Alkaline Flocculation of Chlorella vulgaris Induced by Calcium Phosphate Precipitates.

Czech Academy of Sciences Publication Activity Database

Brányiková, Irena; Filipenská, Monika; Urbanová, K.; Růžička, Marek; Pivokonský, Martin; Brányik, T.

2018-01-01

Roč. 166, 1 June (2018), s. 54-60 ISSN 0927-7765 R&D Projects: GA ČR(CZ) GA18-05007S Institutional support: RVO:67985858 ; RVO:67985874 Keywords : microalgae * calcium phosphate * precipitates * surface interactions Subject RIV: CI - Industrial Chemistry, Chemical Engineering; BK - Fluid Dynamics (UH-J) OBOR OECD: Chemical process engineering; Environmental sciences (social aspects to be 5.7) (UH-J) Impact factor: 3.887, year: 2016

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...

Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes.

Science.gov (United States)

Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

2014-01-01

At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers-which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal-has hitherto been technically impossible. With the aim of quantifying both Ca(2+) currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 pA and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 μM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

CD54-Mediated Interaction with Pro-inflammatory Macrophages Increases the Immunosuppressive Function of Human Mesenchymal Stromal Cells

Directory of Open Access Journals (Sweden)

Nicolas Espagnolle

2017-04-01

Full Text Available Summary: Mesenchymal stromal cells (MSCs sense and modulate inflammation and represent potential clinical treatment for immune disorders. However, many details of the bidirectional interaction of MSCs and the innate immune compartment are still unsolved. Here we describe an unconventional but functional interaction between pro-inflammatory classically activated macrophages (M1MΦ and MSCs, with CD54 playing a central role. CD54 was upregulated and enriched specifically at the contact area between M1MФ and MSCs. Moreover, the specific interaction induced calcium signaling and increased the immunosuppressive capacities of MSCs dependent on CD54 mediation. Our data demonstrate that MSCs can detect an inflammatory microenvironment via a direct and physical interaction with innate immune cells. This finding opens different perspectives for MSC-based cell therapy. : Mesenchymal stromal cells (MSCs are promising for cell-based therapy in inflammatory disorders by switching off the immune response. Varin and colleagues demonstrate that MSCs and inflammatory macrophages communicate via an unconventional but functional interaction that strongly increases the immunosuppressive capacities of MSCs. This new communication between the innate immune system and MSCs opens new perspectives for MSC-based cell therapy. Keywords: macrophages, bone marrow mesenchymal stromal cells, functional interaction, CD54, immunosuppression, indoleamine 2,3-dioxygenase, cell therapy

Research of calcium oxide hydration in calcium nitrate solutions

Directory of Open Access Journals (Sweden)

M.A. Oliynyk

2016-09-01

Full Text Available Mineral fertilizers are one of the important factors of agriculture intensification and increasing of food products quantity. The volume of fertilizers production and its domestic consumption in Ukraine indicate that nitrogen fertilizer using only comes nearer to the required number of science-based. One of the most widespread artificial fertilizers is the calcium nitrate. Aim: The aim is to study and theoretically substantiate the processes occurring in the preparation of suspensions of calcium hydroxide Са(ОН2 in solution of calcium nitrate Ca(NО32. Materials and Methods: The technical calcium oxide (quicklime DSTU BV.2.7-90-99, solutions of calcium nitrate of 15, 20, 25, 30, 35 and 40% Ca(NО32 concentrations were used in the work. The content of lime in the preparation of a suspension in the solution changed (in terms of calcium oxide CaO from 150 g/dm3 to the maximum possible. Each of these solutions saturated at 40°С in lime to maximum concentration. Suitable for use in these experiments and in the technology of calcium nitrate obtaining are considered the solutions (suspensions that within 12 hours did not lose their mobility (transportability. Results: The experimental results show that increasing of the concentration of calcium nitrate in solution within the range 15...40%, the amount of lime that you can put into the solution without loss of transportability decreases. Further increasing of lime quantity in solutions concentrations causes to its solidifying, loss of mobility (transportability. Calculations showed that in the presence of calcium nitrate the solubility of Са(ОН2 is reduced nearly by order that can lead to the formation of calcium oxide CaO the solid phase Са(ОН2 on the surface, which also can form hydrogen bonds with the components of the solution. As the probability of formation of hydrogen bonds in solutions is high, there is a possibility of formation of clusters.

Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.

Science.gov (United States)

Ummadi, Jyothir Ganesh; Downs, Corey J; Joshi, Vrushali S; Ferracane, Jack L; Koley, Dipankar

2016-03-15

Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca(2+)-ISME), 25 μm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca(2+)-ISME has a broad linear response range of 5 μM to 200 mM with a near Nernstian slope of 28 mV/log[a(Ca(2+))]. The calculated detection limit for Ca(2+)-ISME is 1 μM. The selectivity coefficients of this Ca(2+)-ISME are log K(Ca(2+),A) = -5.88, -5.54, and -6.31 for Mg(2+), Na(+), and K(+), respectively. We used this new type of Ca(2+)-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca(2+)] in artificial saliva) to 1.4 mM at 20 μm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca(2+) above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions.

Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

International Nuclear Information System (INIS)

Teir, Sebastian; Eloneva, Sanni; Zevenhoven, Ron

2005-01-01

The possibilities for reducing carbon dioxide emissions from the pulp and paper industry by calcium carbonation are presented. The current precipitated calcium carbonate (PCC) production uses mined, crushed calcium carbonate as raw materials. If calcium silicates were used instead, carbon dioxide emissions from the calcination of carbonates would be eliminated. In Finland, there could, thus, be a potential for eliminating 200 kt of carbon dioxide emissions per year, considering only the PCC used in the pulp and paper industry. A preliminary investigation of the feasibility to produce PCC from calcium silicates and the potential to replace calcium carbonate as the raw material was made. Calcium carbonate can be manufactured from calcium silicates by various methods, but only a few have been experimentally verified. The possibility and feasibility of these methods as a replacement for the current PCC production process was studied by thermodynamic equilibrium calculations using HSC software and process modelling using Aspen Plus[reg]. The results from the process modelling showed that a process that uses acetic acid for extraction of the calcium ions is a high potential option for sequestering carbon dioxide by mineral carbonation. The main obstacle seems to be the limited availability and relatively high price of wollastonite, which is a mineral with high calcium silicate content. An alternative is to use the more common, but also more complex, basalt rock instead

Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

Directory of Open Access Journals (Sweden)

Dmitry eSamigullin

2015-01-01

Full Text Available At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 рА and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 µM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

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

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...

Transcellular transport of calcium

Energy Technology Data Exchange (ETDEWEB)

Terepka, A R; Coleman, J R; Armbrecht, H J; Gunter, T E

1976-01-01

Studies of two calcium transporting epithelia, embryonic chick chorioallantoic membrane and the small intestine of rat and chick, have strongly suggested that the transfer of calcium across a cell involves processes distinctly different from intracellular calcium ion regulation. In the proposed model, transcellular calcium transport is considered as a specialized process developed only by certain cells in those tissues charged with bulk transfer of calcium. The overall effect of the endocytotic mechanism is bulk calcium movement across a cell, protection of mitochondria from exposure to high concentrations of calcium, and the avoidance of wide and potentially toxic fluctuations in cytosol ionic calcium levels. (MFB)

First direct electron microscopic visualization of a tight spatial coupling between GABAA-receptors and voltage-sensitive calcium channels

DEFF Research Database (Denmark)

Hansen, Gert Helge; Belhage, B; Schousboe, A

1992-01-01

Using cerebellar granule neurons in culture it was demonstrated that exposure of the cells to the GABAA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) leads to an increase in the number of voltage-gated calcium channels as revealed by quantitative preembedding indirect imm...

[G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304].

Science.gov (United States)

Lin, L; Zheng, Y; Qu, J; Bao, G

2000-06-01

Observe the effect of tumor necrosis factor-alpha (TNF-alpha) on calcium-activated potassium channel in ECV304 and the possible involvement of G-protein mediation in the action of TNF-alpha. Using the cell-attached configuration of patch clamp technique. (1) the activity of high-conductance calcium-activated potassium channel (BKca) was recorded. Its conductance is (202.54 +/- 16.62) pS; (2) the activity of BKca was potentiated by 200 U/ml TNF-alpha; (3) G-protein would intensify this TNF-alpha activation. TNF-alpha acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKca. Opening of BKca resulted in membrane hyper-polarization which could increase electro-chemical gradient for the resting Ca2+ influx and open leakage calcium channel, thus resting cytoplasmic free Ca2+ concentration could be elevated. G-protein may exert an important regulation in this process.

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 ...

Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

International Nuclear Information System (INIS)

Li, Xuerun; Zhang, Yu; Shen, Xiaodong; Wang, Qianqian; Pan, Zhigang

2014-01-01

The formation kinetics of tricalcium aluminate (C 3 A) and calcium sulfate yielding calcium sulfoaluminate (C 4 A 3 $) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C 3 A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca 3 Al 2 O 6 + CaSO 4 → Ca 4 Al 6 O 12 (SO 4 ) + 6CaO was the primary reaction 4 Al 6 O 12 (SO 4 ) + 10CaO → 6Ca 3 Al 2 O 6 + 2SO 2 ↑ + O 2 ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C 4 A 3 $ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C 4 A 3 $ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca 2+ and SO 4 2− were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C 3 A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion

Why Calcium? How Calcium Became the Best Communicator*

Science.gov (United States)

Carafoli, Ernesto; Krebs, Joachim

2016-01-01

Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these “calcium sensors” are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. PMID:27462077

Codissolution of calcium hydrogenphosphate and sodium hydrogencitrate in water. Spontaneous supersaturation of calcium citrate increasing calcium bioavailability

DEFF Research Database (Denmark)

Hedegaard, Martina Vavrusova; Danielsen, Bente Pia; Garcia, André Castilho

2018-01-01

The sparingly soluble calcium hydrogenphosphate dihydrate, co-dissolving in water during dissolution of freely soluble sodium hydrogencitrate sesquihydrate as caused by proton transfer from hydrogencitrate to hydrogenphosphate, was found to form homogenous solutions supersaturated by a factor up...... to 8 in calcium citrate tetrahydrate. A critical hydrogencitrate concentration for formation of homogeneous solutions was found to depend linearly on dissolved calcium hydrogenphosphate: [HCitr2-] = 14[CaHPO4] - 0.05 at 25 °C. The lag phase for precipitation of calcium citrate tetrahydrate......, as identified from FT-IR spectra, from these spontaneously formed supersaturated solutions was several hours, and the time to reach solubility equilibrium was several days. Initial calcium ion activity was found to be almost independent of the degree of supersaturation as determined electrochemically...

Calcium blood test

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003477.htm Calcium blood test To use the sharing features on this page, please enable JavaScript. The calcium blood test measures the level of calcium in the blood. ...

Calcium carbonate overdose

Science.gov (United States)

Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Products that contain calcium carbonate are certain: Antacids (Tums, Chooz) Mineral supplements Hand lotions Vitamin and mineral supplements Other products may also contain ...

Calcium: the molecular basis of calcium action in biology and medicine

National Research Council Canada - National Science Library

Pochet, Roland; Donato, Rosario

2000-01-01

... of Calcium Calcium Signalling in Excitable Cells Ca2+ Release in Muscle Cells by N. Macrez and J. Mironneau Calcium Signalling in Neurons Exemplified by Rat Sympathetic Ganglion Cells by S.J. M...

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 ...

Calcium ferrite formation from the thermolysis of calcium tris (maleato)

Indian Academy of Sciences (India)

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 ...

Kinetic identification of an intracellular calcium compartment sensitive to phosphate and dinitrophenol in intact isolated rabbit aorta

International Nuclear Information System (INIS)

Hai, C.M.; Phair, R.D.

1986-01-01

Previous work from this laboratory revealed the presence of at least three distinct intracellular calcium compartments in intact segments of rabbit aorta. In this study one of these intracellular compartments is shown to be sensitive to dinitrophenol and to increased extracellular phosphate. Intact aortic segments were loaded with 45 Ca in bicarbonate-buffered physiologic salt solution for 1 hour, and then transferred to a flow-through chamber perfused with physiologic salt solution. Effluent from the chamber was collected for 8 hours, and 45 Ca efflux curves were analyzed using compartmental analysis. When aortic segments were loaded and washed out in dinitrophenol, the slowest component of the efflux curve was less prominent; in high phosphate it was more prominent. The rate constant changes required to account for these data were primarily in the exchange between the cytosolic and slowest intracellular calcium compartment, suggesting that the slowest calcium compartment resolved during the 8-hour washout was mitochondrial. This compartment contained 5.4 +/- 3.2 nmol calcium/g wet wt. tissue. The calcium flux across its membranes was 0.32 +/- 0.04 nmol min-1g-1. Because this flux is much smaller than the plasma-membrane calcium flux, we suggest that, in normal physiological circumstances, plasma-membrane extrusion is more important for the removal of Ca from the smooth muscle cytosol than is uptake into this slow intracellular compartment

The effect of habitat geology on calcium intake and calcium status of wild rodents.

Science.gov (United States)

Shore, R F; Balment, R J; Yalden, D W

1991-12-01

Calcium is essential for normal physiological function, reproduction and growth in mammals but its distribution in the natural environment is heterogeneous. Spatial variation in calcium soil content is especially marked in the Peak District, United Kingdom, where both calcium-rich limestone and calcium-poor gritstone rock types occur. Wood mice Apodemus sylvaticus (L) and bank voles Clethrionomys glareolus (Schreber 1780) from limestone areas had significantly higher calcium concentrations in stomach contents and in faeces compared with their counterparts from gritstone areas. Calcium status was assessed from serum calcium concentration, femur weight, ash content of the body, calcium concentration in the femur and body ash. There was no significant difference in serum calcium concentration, femur calcium concentration and body ash calcium concentration between animals from the limestone and the gritstone. However, on the limestone, bank voles, but not wood mice, had significantly heavier femora and a greater proportion of ash in the body compared with their gritstone counterparts.

Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce

Science.gov (United States)

Kevin T. Smith; Walter C. Shortle; Jon H. Connolly; Rakesh Minocha; Jody Jellison

2009-01-01

Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of...

Why Calcium? How Calcium Became the Best Communicator.

Science.gov (United States)

Carafoli, Ernesto; Krebs, Joachim

2016-09-30

Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these "calcium sensors" are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

The normal range of serum calcium and phosphorus in 20-69 years population of Bushehr Port

Directory of Open Access Journals (Sweden)

Iraj Nabipour

2003-09-01

Full Text Available Serum calcium and phosphorus levels are the important biochemical markers of bone in health and disease. The normal range of these bone biochemical markers belong to the populations with different racial and nutritional states. In order to determine normal range of these elements, fasting sera of 1463 (619 males and 749 females, 20-69 years old healthy subjects were evaluated using Selectra autoanalyser. The subjects had not disorder of bone and predisposing conditions for osteoporosis. The mean of serum calcium level was 9.26 mg/dl (CI: 95%, 9.22-9.31 mg/dl for females and 9.43-9.54 mg/dl for males. The mean of serum phosphorus level was 4.12 mg/dl (CI: 95%, 4.16-4.24 mg/dl for females and 3.97-4.07 for males. Therefore, calcium and phosphorus levels are in concordance to international standard normal range in Bushehr port.

An overview of techniques for the measurement of calcium distribution, calcium fluxes, and cytosolic free calcium in mammalian cells

International Nuclear Information System (INIS)

Borle, A.B.

1990-01-01

An array of techniques can be used to study cell calcium metabolism that comprises several calcium compartments and many types of transport systems such as ion channels, ATP-dependent pumps, and antiporters. The measurement of total call calcium brings little information of value since 60 to 80% of total cell calcium is actually bound to the extracellular glycocalyx. Cell fractionation and differential centrifugation have been used to study intracellular Ca 2+ compartmentalization, but the methods suffer from the possibility of Ca 2+ loss or redistribution among cell fractions. Steady-state kinetic analyses of 45 Ca uptake or desaturation curves have been used to study the distribution of Ca 2+ among various kinetic pools in living cells and their rate of Ca 2+ exchange, but the analyses are constrained by many limitations. Nonsteady-state tracer studies can provide information about rapid changes in calcium influx or efflux in and out of the cell. Zero-time kinetics of 45 Ca uptake can detect instantaneous changes in calcium influx, while 45 Ca fractional efflux ratio, can detect rapid stimulations or inhibitions of calcium efflux out of cells. The best strategy to study cell calcium metabolism is to use several different methods that focus on a specific problem from widely different angles

The role of Candida albicans homologous recombination factors Rad54 and Rdh54 in DNA damage sensitivity

Directory of Open Access Journals (Sweden)

White Theodore C

2011-09-01

Full Text Available Abstract Background The fungal pathogen Candida albicans is frequently seen in immune suppressed patients, and resistance to one of the most widely used antifungals, fluconazole (FLC, can evolve rapidly. In recent years it has become clear that plasticity of the Candida albicans genome contributes to drug resistance through loss of heterozygosity (LOH at resistance genes and gross chromosomal rearrangements that amplify gene copy number of resistance associated genes. This study addresses the role of the homologous recombination factors Rad54 and Rdh54 in cell growth, DNA damage and FLC resistance in Candida albicans. Results The data presented here support a role for homologous recombination in cell growth and DNA damage sensitivity, as Candida albicans rad54Δ/rad54Δ mutants were hypersensitive to MMS and menadione, and had an aberrant cell and nuclear morphology. The Candida albicans rad54Δ/rad54Δ mutant was defective in invasion of Spider agar, presumably due to the altered cellular morphology. In contrast, mutation of the related gene RDH54 did not contribute significantly to DNA damage resistance and cell growth, and deletion of either Candida albicans RAD54 or Candida albicans RDH54 did not alter FLC susceptibility. Conclusions Together, these results support a role for homologous recombination in genome stability under nondamaging conditions. The nuclear morphology defects in the rad54Δ/rad54Δ mutants show that Rad54 performs an essential role during mitotic growth and that in its absence, cells arrest in G2. The viability of the single mutant rad54Δ/rad54Δ and the inability to construct the double mutant rad54Δ/rad54Δ rdh54Δ/rdh54Δ suggests that Rdh54 can partially compensate for Rad54 during mitotic growth.

Calcium dependence of uni-quantal release latencies and quantal content at mouse neuromuscular junction

Czech Academy of Sciences Publication Activity Database

Samigullin, D.; Bukharaeva, E. A.; Vyskočil, František; Nikolsky, E. E.

2005-01-01

Roč. 54, č. 1 (2005), s. 129-132 ISSN 0862-8408 R&D Projects: GA AV ČR(CZ) IAA5011411; GA ČR(CZ) GA305/02/1333 Grant - others:RFBR(RU) 05-04-49723; Russian Science Support Foundation(RU) 1063.2003.4; GA-(RU) MK-2153.2003.04 Institutional research plan: CEZ:AV0Z50110509 Keywords : quantal release * synaptic latency * calcium Subject RIV: ED - Physiology Impact factor: 1.806, year: 2005

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.

Calcium ion binding properties of Medicago truncatula calcium/calmodulin-dependent protein kinase.

Science.gov (United States)

Swainsbury, David J K; Zhou, Liang; Oldroyd, Giles E D; Bornemann, Stephen

2012-09-04

A calcium/calmodulin-dependent protein kinase (CCaMK) is essential in the interpretation of calcium oscillations in plant root cells for the establishment of symbiotic relationships with rhizobia and mycorrhizal fungi. Some of its properties have been studied in detail, but its calcium ion binding properties and subsequent conformational change have not. A biophysical approach was taken with constructs comprising either the visinin-like domain of Medicago truncatula CCaMK, which contains EF-hand motifs, or this domain together with the autoinhibitory domain. The visinin-like domain binds three calcium ions, leading to a conformational change involving the exposure of hydrophobic surfaces and a change in tertiary but not net secondary or quaternary structure. The affinity for calcium ions of visinin-like domain EF-hands 1 and 2 (K(d) = 200 ± 50 nM) was appropriate for the interpretation of calcium oscillations (~125-850 nM), while that of EF-hand 3 (K(d) ≤ 20 nM) implied occupancy at basal calcium ion levels. Calcium dissociation rate constants were determined for the visinin-like domain of CCaMK, M. truncatula calmodulin 1, and the complex between these two proteins (the slowest of which was 0.123 ± 0.002 s(-1)), suggesting the corresponding calcium association rate constants were at or near the diffusion-limited rate. In addition, the dissociation of calmodulin from the protein complex was shown to be on the same time scale as the dissociation of calcium ions. These observations suggest that the formation and dissociation of the complex between calmodulin and CCaMK would substantially mirror calcium oscillations, which typically have a 90 s periodicity.

Calcium Carbonate

Science.gov (United States)

... Calcium is needed by the body for healthy bones, muscles, nervous system, and heart. Calcium carbonate also ... to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in ...

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

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

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.

Calcium - ionized

Science.gov (United States)

... diuretics Thrombocytosis (high platelet count) Tumors Vitamin A excess Vitamin D excess Lower-than-normal levels may be due to: Hypoparathyroidism Malabsorption Osteomalacia Pancreatitis Renal failure Rickets Vitamin D deficiency Alternative Names Free calcium; Ionized calcium ...

Calcium absorption and achlorhydria

International Nuclear Information System (INIS)

Recker, R.R.

1985-01-01

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

Study of calcium chloride and calcium nitrate purification on inorganic sorbents

International Nuclear Information System (INIS)

Vasil'eva, L.V.; Knyazeva, A.N.; Fakeev, A.A.; Belyaeva, N.A.; Morozov, V.I.; Kucherova, V.V.

1986-01-01

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.

Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

International Nuclear Information System (INIS)

Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku

2006-01-01

Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

Calcium sensing in exocytosis

DEFF Research Database (Denmark)

Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

2012-01-01

an increase in intracellular calcium levels. Besides the triggering role, calcium signaling modulates the precise amount and kinetics of vesicle release. Thus, it is a central question to understand the molecular machineries responsible for calcium sensing in exocytosis. Here we provide an overview of our...... current understanding of calcium sensing in neurotransmitter release and hormone secretion....

Time bound changes (in 24 h in human sperm motility and level of calcium and magnesium in seminal plasma

Directory of Open Access Journals (Sweden)

J. Valsa

2016-09-01

Level of calcium (27.2 mg/dl and magnesium (13.54 mg/dl in seminal plasma did not show any significant changes during study period from that of at ½ h. The study concluded that electrolytes under study were not responsible for the decrease in motility during study period.

CALCIUM-RICH GAP TRANSIENTS: SOLVING THE CALCIUM CONUNDRUM IN THE INTRACLUSTER MEDIUM

International Nuclear Information System (INIS)

Mulchaey, John S.; Kollmeier, Juna A.; Kasliwal, Mansi M.

2014-01-01

X-ray measurements suggest that the abundance of calcium in the intracluster medium is higher than can be explained using favored models for core-collapse and Type Ia supernovae alone. We investigate whether the ''calcium conundrum'' in the intracluster medium can be alleviated by including a contribution from the recently discovered subclass of supernovae known as calcium-rich gap transients. Although the calcium-rich gap transients make up only a small fraction of all supernovae events, we find that their high calcium yields are sufficient to reproduce the X-ray measurements found for nearby rich clusters. We find the χ 2 goodness-of-fit metric improves from 84 to 2 by including this new class. Moreover, calcium-rich supernovae preferentially occur in the outskirts of galaxies making it easier for the nucleosynthesis products of these events to be incorporated in the intracluster medium via ram-pressure stripping. The discovery of calcium-rich gap transients in clusters and groups far from any individual galaxy suggests that supernovae associated with intracluster stars may play an important role in enriching the intracluster medium. Calcium-rich gap transients may also help explain anomalous calcium abundances in many other astrophysical systems including individual stars in the Milky Way, the halos of nearby galaxies, and the circumgalactic medium. Our work highlights the importance of considering the diversity of supernovae types and corresponding yields when modeling the abundance of the intracluster medium and other gas reservoirs

Estimation of ionized calcium, total calcium and albumin corrected calcium for the diagnosis of hypocalcaemia of malignancy

International Nuclear Information System (INIS)

Ijaz, A.; Mehmood, T.; Qureshi, A.H.; Anwar, M.; Dilawar, M.; Hussain, I.; Khan, F.A.; Khan, D.A.; Hussain, S.; Khan, I.A.

2006-01-01

Objective: To measure levels of ionized calcium, total calcium and albumin corrected calcium in patients with different malignant disorders for the diagnosis of hypercalcaemia of malignancy. Design: A case control comparative study. Place and Duration of Study: The study was carried out in the Department of Pathology, Army Medical College Rawalpindi, Armed Forces Institute of Pathology and Department of Oncology CMH, Rawalpindi from March 2003 to December 2003. Subjects and Methods: Ninety-seven patients of various malignant disorders, admitted in the Department of Oncology, CMH, Rawalpindi, and 39 age and gender-matched disease-free persons (as control) were included in the study. Blood ionized calcium (Ca/sup ++/), pH, sodium (Na/sup +/) and potassium (K/sup +/) were analysed by Ion selective electrode (ISE) on Easylyte> auto analyser. Other related parameters were measured by colorimetric methods. Results: Blood Ca/sup ++/ levels in patients suffering from malignant disorders were found significantly high (mean +- j 1.30+017 mmoV/L) as compared to control subjects (mean +- 1.23+0.03 mmoV/L) (p<0.001). The number of patients with hypercalcaemia of malignancy detected by Ca/sup ++/ estimation was significantly higher (38%) as compared to total calcium (8.4%) and albumin corrected calcium ACC (10.6%) (p<0.001). There was no statistically significant difference in other parameters e.g. phosphate, urea, creatinine, pH, Na/sup +/ and K/sup +/ levels in study subjects and controls. Conclusion: Detection of hypercalcaemia can be markedly improved if ionized calcium estimation is used in patients with malignant disorders. (author)

SR calcium handling and calcium after-transients in a rabbit model of heart failure

NARCIS (Netherlands)

Baartscheer, Antonius; Schumacher, Cees A.; Belterman, Charly N. W.; Coronel, Ruben; Fiolet, Jan W. T.

2003-01-01

Objective: After-depolarization associated arrhythmias are frequently observed in heart failure and associated with spontaneous calcium release from sarcoplasmic reticulum (SR), calcium after-transients. We hypothesize that disturbed SR calcium handling underlies calcium after-transients in heart

Calcium absorption from fortified ice cream formulations compared with calcium absorption from milk.

Science.gov (United States)

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

2009-05-01

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-fortified ice cream formulation that is lower in fat than regular ice cream and could provide a useful source of additional dietary calcium. Calcium absorption from two different ice cream formulations was determined in young adults and compared with milk. Sixteen healthy volunteers (25 to 45 years of age), recruited from the general public of The Netherlands, participated in a randomized, reference-controlled, double-blind cross-over study in which two test products and milk were consumed with a light standard breakfast on three separate occasions: a standard portion of ice cream (60 g) fortified with milk minerals and containing a low level (3%) of butter fat, ice cream (60 g) fortified with milk minerals and containing a typical level (9%) of coconut oil, and reduced-fat milk (1.7% milk fat) (200 mL). Calcium absorption was measured by the dual-label stable isotope technique. Effects on calcium absorption were evaluated by analysis of variance. Fractional absorption of calcium from the 3% butterfat ice cream, 9% coconut oil ice cream, and milk was 26%+/-8%, 28%+/-5%, and 31%+/-9%, respectively, and did not differ significantly (P=0.159). Results indicate that calcium bioavailability in the two calcium-fortified ice cream formulations used in this study is as high as milk, indicating that ice cream may be a good vehicle for delivery of calcium.

47 CFR 54.516 - Auditing.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Auditing. 54.516 Section 54.516 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Universal Service Support for Schools and Libraries § 54.516 Auditing. (a) Recordkeeping...

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

28 CFR 54.200 - Application.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Application. 54.200 Section 54.200 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Coverage § 54.200 Application...

7 CFR 54.3 - Authority.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Authority. 54.3 Section 54.3 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections... PRODUCTS (GRADING, CERTIFICATION, AND STANDARDS) Regulations Administration § 54.3 Authority. The Chief is...

An Exploration of the Calcium-Binding Mode of Egg White Peptide, Asp-His-Thr-Lys-Glu, and In Vitro Calcium Absorption Studies of Peptide-Calcium Complex.

Science.gov (United States)

Sun, Na; Jin, Ziqi; Li, Dongmei; Yin, Hongjie; Lin, Songyi

2017-11-08

The binding mode between the pentapeptide (DHTKE) from egg white hydrolysates and calcium ions was elucidated upon its structural and thermodynamics characteristics. The present study demonstrated that the DHTKE peptide could spontaneously bind calcium with a 1:1 stoichiometry, and that the calcium-binding site corresponded to the carboxyl oxygen, amino nitrogen, and imidazole nitrogen atoms of the DHTKE peptide. Moreover, the effect of the DHTKE-calcium complex on improving the calcium absorption was investigated in vitro using Caco-2 cells. Results showed that the DHTKE-calcium complex could facilitate the calcium influx into the cytosol and further improve calcium absorption across Caco-2 cell monolayers by more than 7 times when compared to calcium-free control. This study facilitates the understanding about the binding mechanism between peptides and calcium ions as well as suggests a potential application of egg white peptides as nutraceuticals to improve calcium absorption.

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

Science.gov (United States)

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

2014-01-01

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

The 54Fe(d,t)53Fe reaction and the neutron configuration in 54Fe

International Nuclear Information System (INIS)

England, J.B.A.; Ophel, T.R.; Johnston, A.; Zeller, A.F.

1980-07-01

The 54 Fe(d,t) 53 Fe reaction has been used to study the levels populated in 54 Fe in an attempt to establish the neutron configuration in 54 Fe. The states observed show clear evidence for a 2p-4h admixture in 54 Fe. In particular, the strength of the first 3/2 - level relative to the 7/2 - ground state transition is 3-4 times that in neighbouring N = 28 nuclei

28 CFR 54.310 - Recruitment.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recruitment. 54.310 Section 54.310... in Admission and Recruitment Prohibited § 54.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment efforts...

28 CFR 54.540 - Advertising.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Advertising. 54.540 Section 54.540... in Employment in Education Programs or Activities Prohibited § 54.540 Advertising. A recipient shall not in any advertising related to employment indicate preference, limitation, specification, or...

28 CFR 54.500 - Employment.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Employment. 54.500 Section 54.500... in Employment in Education Programs or Activities Prohibited § 54.500 Employment. (a) General. (1) No... subjected to discrimination in employment, or recruitment, consideration, or selection therefor, whether...

Calcium carbonate scaling kinetics determined from radiotracer experiments with calcium-47

International Nuclear Information System (INIS)

Turner, C.W.; Smith, D.W.

1998-01-01

The deposition rate of calcium carbonate on a heat-transfer surface has been measured using a calcium-47 radiotracer and compared to the measured rate of thermal fouling. The crystalline phase of calcium carbonate that precipitates depends on the degree of supersaturation at the heat-transfer surface, with aragonite precipitating at higher supersaturations and calcite precipitating at lower supersaturations. Whereas the mass deposition rates were constant with time, the thermal fouling rates decreased throughout the course of each experiment as a result of densification of the deposit. It is proposed that the densification was driven by the temperature gradient across the deposit together with the retrograde solubility of calcium carbonate. The temperature dependence of the deposition rate yielded an activation energy of 79 ± 4 kJ/mol for the precipitation of calcium carbonate on a heat-transfer surface. (author)

Calcium Signaling in Taste Cells

Science.gov (United States)

Medler, Kathryn F.

2014-01-01

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. PMID:25450977

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 ...

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 ...

Antenatal calcium intake in Malaysia.

Science.gov (United States)

Mahdy, Zaleha Abdullah; Basri, Hashimah; Md Isa, Zaleha; Ahmad, Shuhaila; Shamsuddin, Khadijah; Mohd Amin, Rahmah

2014-04-01

To determine the adequacy of antenatal calcium intake in Malaysia, and the influencing factors. A cross-sectional study was conducted among postnatal women who delivered in two tertiary hospitals. Data were collected from antenatal cards, hospital documents and diet recall on daily milk and calcium intake during pregnancy. SPSS version 19.0 was used for statistical analyses. A total of 150 women were studied. The total daily calcium intake was 834 ± 43 mg (mean ± standard error of the mean), but the calcium intake distribution curve was skewed to the right with a median intake of 725 mg daily. When calcium intake from milk and calcium supplements was excluded, the daily dietary calcium intake was only 478 ± 25 mg. Even with inclusion of milk and calcium supplements, more than a third (n=55 or 36.7%) of the women consumed less than 600 mg calcium in their daily diet. The adequacy of daily calcium intake was not influenced by maternal age, ethnicity, income or maternal job or educational status as well as parity. The daily dietary calcium intake of the Malaysian antenatal population is far from adequate without the addition of calcium supplements and milk. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

28 CFR 54.510 - Recruitment.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recruitment. 54.510 Section 54.510... in Employment in Education Programs or Activities Prohibited § 54.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the recruitment...

Calcium channel blocker poisoning

Directory of Open Access Journals (Sweden)

Miran Brvar

2005-04-01

Full Text Available Background: Calcium channel blockers act at L-type calcium channels in cardiac and vascular smooth muscles by preventing calcium influx into cells with resultant decrease in vascular tone and cardiac inotropy, chronotropy and dromotropy. Poisoning with calcium channel blockers results in reduced cardiac output, bradycardia, atrioventricular block, hypotension and shock. The findings of hypotension and bradycardia should suggest poisoning with calcium channel blockers.Conclusions: Treatment includes immediate gastric lavage and whole-bowel irrigation in case of ingestion of sustainedrelease products. All patients should receive an activated charcoal orally. Specific treatment includes calcium, glucagone and insulin, which proved especially useful in shocked patients. Supportive care including the use of catecholamines is not always effective. In the setting of failure of pharmacological therapy transvenous pacing, balloon pump and cardiopulmonary by-pass may be necessary.

Energetics of sodium-calcium exchanged zeolite A.

Science.gov (United States)

Sun, H; Wu, D; Guo, X; Shen, B; Navrotsky, A

2015-05-07

A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

Impaired calcium sensing distinguishes primary hyperparathyroidism (PHPT) patients with low bone mineral density.

Science.gov (United States)

Weber, Thomas J; Koh, James; Thomas, Samantha M; Hogue, Joyce A; Scheri, Randall P; Roman, Sanziana A; Sosa, Julie A

2017-09-01

A subset of PHPT patients exhibit a more severe disease phenotype characterized by bone loss, fractures, recurrent nephrolithiasis, and other dysfunctions, but the underlying reasons for this disparity in clinical presentation remain unknown. We sought to identify new mechanistic indices that could inform more personalized management of PHPT. Pre-, peri-, and postoperative data and demographic, clinical, and pathological information from patients undergoing parathyroidectomy for PHPT were collected. Univariate and partial Spearman correlation was used to estimate the association of parathyroid tumor calcium sensing capacity with select variables. An unselected series of 237 patients aged >18years and undergoing parathyroidectomy for PHPT were enrolled. Calcium sensing capacity, expressed as the concentration required for half-maximal biochemical response (EC50), was evaluated in parathyroid tumors from an unselected series of 74 patients and assessed for association with clinical parameters. The hypothesis was that greater disease severity would be associated with attenuated calcium sensitivity and biochemically autonomous parathyroid tumor behavior. Parathyroid tumors segregated into two distinct groups of calcium responsiveness (EC50calcium EC50 value of 2.49mM [95% confidence interval (CI): 2.43-2.54mM], consistent with reference normal activity. In contrast, the high EC50 group (n=47) displayed attenuated calcium sensitivity with a mean EC50 value of 3.48mM [95% CI: 3.41-3.55mM]. Retrospective analysis of the clinical registry data suggested that high calcium EC50 patients presented with a more significant preoperative bone mineral density (BMD) deficit with a t-score of -2.7, (95% CI: -3.4 to -1.9) versus 0.9, (95% CI: -2.1 to -0.4) in low EC50 patients (pcalcium EC50 were inversely correlated, with a partial Spearman correlation coefficient of -0.35 (p=0.02). Impaired calcium sensing in parathyroid tumors is selectively observed in a subset of patients with

The Hepatitis B Virus X Protein Elevates Cytosolic Calcium Signals by Modulating Mitochondrial Calcium Uptake

Science.gov (United States)

Yang, Bei

2012-01-01

Chronic hepatitis B virus (HBV) infections are associated with the development of hepatocellular carcinoma (HCC). The HBV X protein (HBx) is thought to play an important role in the development of HBV-associated HCC. One fundamental HBx function is elevation of cytosolic calcium signals; this HBx activity has been linked to HBx stimulation of cell proliferation and transcription pathways, as well as HBV replication. Exactly how HBx elevates cytosolic calcium signals is not clear. The studies described here show that HBx stimulates calcium entry into cells, resulting in an increased plateau level of inositol 1,4,5-triphosphate (IP3)-linked calcium signals. This increased calcium plateau can be inhibited by blocking mitochondrial calcium uptake and store-operated calcium entry (SOCE). Blocking SOCE also reduced HBV replication. Finally, these studies also demonstrate that there is increased mitochondrial calcium uptake in HBx-expressing cells. Cumulatively, these studies suggest that HBx can increase mitochondrial calcium uptake and promote increased SOCE to sustain higher cytosolic calcium and stimulate HBV replication. PMID:22031934

7 CFR 1030.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54. ...

Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

OpenAIRE

Zenei Taira, Zenei; Ueda,Yukari

2013-01-01

Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

7 CFR 1005.54 - Equivalent price.

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2010-01-01

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7 CFR 1126.54 - Equivalent price.

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2010-01-01

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7 CFR 1001.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential ...

7 CFR 1032.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential ...

7 CFR 1033.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential ...

7 CFR 1131.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices ...

7 CFR 1006.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices ...

7 CFR 1007.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices ...

Voltage-Gated Calcium Channels

Science.gov (United States)

Zamponi, Gerald Werner

Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

7 CFR 701.54 - Oysters.

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2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Oysters. 701.54 Section 701.54 Agriculture Regulations... ADMINISTERED UNDER THIS PART § 701.54 Oysters. (a) Notwithstanding § 701.5(b), but otherwise subject to the... be made available under this section for the eligible cost of refurbishing public or private oyster...

28 CFR 54.405 - Housing.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Housing. 54.405 Section 54.405 Judicial... Activities Prohibited § 54.405 Housing. (a) Generally. A recipient shall not, on the basis of sex, apply... benefits related to housing, except as provided in this section (including housing provided only to married...

47 CFR 54.623 - Cap.

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2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Cap. 54.623 Section 54.623 Telecommunication... Universal Service Support for Health Care Providers § 54.623 Cap. (a) Amount of the annual cap. The annual cap on federal universal service support for health care providers shall be $400 million per funding...

47 CFR 54.507 - Cap.

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2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Cap. 54.507 Section 54.507 Telecommunication... Universal Service Support for Schools and Libraries § 54.507 Cap. (a) Amount of the annual cap. The annual funding cap on federal universal service support for schools and libraries shall be $2.25 billion per...

7 CFR 1124.54 - Equivalent price.

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2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential ...

21 CFR 54.3 - Scope.

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2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Scope. 54.3 Section 54.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL FINANCIAL DISCLOSURE BY CLINICAL INVESTIGATORS § 54.3 Scope. The requirements in this part apply to any applicant who submits a marketing...

The influence of calcium-45 on the inhibitive effect of calcium hexameta-phosphate combination and the electrocapillary effect of calcium-45

International Nuclear Information System (INIS)

Subramanyan, N.; Venkatakrishna Iyer, S.; Kapali, V.

1978-01-01

Corrosion of steel in an aqueous chloride solution is significantly accelerated if calcium (NaHMP)-45 is substituted for ordinary calcium when calcium and sodium metaphosphate combination was investigated for inhibiting action. In this investigation it is seen that the anodic polarisation of steel is brought down when 45 Ca is present in the different solutions containing Ca, non radioactive calcium and (NaHMP) at pH 5.5, 7.5 and 9.0 except in one case when 45 Ca is present alone in the solution of pH 5.5. The uptake of 45 Ca is more at the positive potentials than at the negative. Electrocapillary measurements with calcium chloride solution show that the electrocapillary curve is lifted above that for the base solution particularly on the positive side of the electrocapillary maximum. These interesting observations are explained by the postulate that radioactive calcium behaves like an anion and the acceleration of corrosion is attributed essentially to radiolytically produced hydrogen peroxide. (author)

Calcium binding by dietary fibre

International Nuclear Information System (INIS)

James, W.P.T.; Branch, W.J.; Southgate, D.A.T.

1978-01-01

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)

Dengue and Calcium

OpenAIRE

Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

2014-01-01

Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

International Nuclear Information System (INIS)

Pham Minh, Doan; Lyczko, Nathalie; Sebei, Haroun; Nzihou, Ange; Sharrock, Patrick

2012-01-01

Highlights: ► Calcium hydroxyapatite was synthesized from CaCO 3 and four orthophosphates. ► Only H 3 PO 4 led to the complete precipitation of orthophosphate species. ► H 3 PO 4 was also the most efficient for calcium dissolution. ► Reaction pathway was dissolution-precipitation accompanied by agglomeration step. - Abstract: The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.

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

NARCIS (Netherlands)

Hsu, Y.J.; Dimke, H.; Schoeber, J.P.H.; Hsu, S.C.; Lin, S.H.; Chu, P.; Hoenderop, J.G.J.; Bindels, R.J.M.

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

Calcium metabolism in birds.

Science.gov (United States)

de Matos, Ricardo

2008-01-01

Calcium is one of the most important plasma constituents in mammals and birds. It provides structural strength and support (bones and eggshell) and plays vital roles in many of the biochemical reactions in the body. The control of calcium metabolism in birds is highly efficient and closely regulated in a number of tissues, primarily parathyroid gland, intestine, kidney, and bone. The hormones with the greatest involvement in calcium regulation in birds are parathyroid hormone, 1,25-dihydroxyvitamin D(3) (calcitriol), and estrogen, with calcitonin playing a minor and uncertain role. The special characteristics of calcium metabolism in birds, mainly associated with egg production, are discussed, along with common clinical disorders secondary to derangements in calcium homeostasis.

Calcium Balance in Chronic Kidney Disease.

Science.gov (United States)

Hill Gallant, Kathleen M; Spiegel, David M

2017-06-01

The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balance have important implications in patients with chronic kidney disease, where negative balance may increase risk of osteoporosis and fracture and positive balance may increase risk of vascular calcification and cardiovascular events. Here, we examine the state of current knowledge about calcium balance in adults throughout the stages of chronic kidney disease and discuss recommendations for clinical strategies to maintain balance as well as future research needs in this area. Recent calcium balance studies in adult patients with chronic kidney disease show that neutral calcium balance is achieved with calcium intake near the recommended daily allowance. Increases in calcium through diet or supplements cause high positive calcium balance, which may put patients at risk for vascular calcification. However, heterogeneity in calcium balance exists among these patients. Given the available calcium balance data in this population, it appears clinically prudent to aim for recommended calcium intakes around 1000 mg/day to achieve neutral calcium balance and avoid adverse effects of either negative or positive calcium balance. Assessment of patients' dietary calcium intake could further equip clinicians to make individualized recommendations for meeting recommended intakes.

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 ...

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

Science.gov (United States)

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

1992-01-01

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

Laboratory study on the high-temperature capture of HCl gas by dry-injection of calcium-based sorbents.

Science.gov (United States)

Shemwell, B; Levendis, Y A; Simons, G A

2001-01-01

This is a laboratory study on the reduction of combustion-generated hydrochloric acid (HCl) emissions by in-furnace dry-injection of calcium-based sorbents. HCl is a hazardous gaseous pollutant emitted in significant quantities by municipal and hazardous waste incinerators, coal-fired power plants, and other industrial furnaces. Experiments were conducted in a laboratory furnace at gas temperatures of 600-1000 degrees C. HCl gas diluted with N2, and sorbent powders fluidized in a stream of air were introduced into the furnace concurrently. Chlorination of the sorbents occurred in the hot zone of the furnace at gas residence times approximately 1 s. The sorbents chosen for these experiments were calcium formate (CF), calcium magnesium acetate (CMA), calcium propionate (CP), calcium oxide (CX), and calcium carbonate (CC). Upon release of organic volatiles, sorbents calcine to CaO at approximately 700 degrees C, and react with the HCl according to the reaction CaO + 2HCl CaCl2 + H2O. At the lowest temperature case examined herein, 600 degrees C, direct reaction of HCl with CaCO3 may also be expected. The effectiveness of the sorbents to capture HCl was interpreted using the "pore tree" mathematical model for heterogeneous diffusion reactions. Results show that the thin-walled, highly porous cenospheres formed from the pyrolysis and calcination of CF, CMA, and CP exhibited high relative calcium utilization at the upper temperatures of this study. Relative utilizations under these conditions reached 80%. The less costly low-porosity sorbents, calcium carbonate and calcium oxide also performed well. Calcium carbonate reached a relative utilization of 54% in the mid-temperature range, while the calcium oxide reached an 80% relative utilization at the lowest temperature examined. The data matched theoretical predictions of sorbent utilization using the mathematical model, with activation energy and pre-exponential factors for the calcination reaction of 17,000 K and 300

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.

Live Imaging of Calcium Dynamics during Axon Degeneration Reveals Two Functionally Distinct Phases of Calcium Influx

Science.gov (United States)

Yamagishi, Yuya; Tessier-Lavigne, Marc

2015-01-01

Calcium is a key regulator of axon degeneration caused by trauma and disease, but its specific spatial and temporal dynamics in injured axons remain unclear. To clarify the function of calcium in axon degeneration, we observed calcium dynamics in single injured neurons in live zebrafish larvae and tested the temporal requirement for calcium in zebrafish neurons and cultured mouse DRG neurons. Using laser axotomy to induce Wallerian degeneration (WD) in zebrafish peripheral sensory axons, we monitored calcium dynamics from injury to fragmentation, revealing two stereotyped phases of axonal calcium influx. First, axotomy triggered a transient local calcium wave originating at the injury site. This initial calcium wave only disrupted mitochondria near the injury site and was not altered by expression of the protective WD slow (WldS) protein. Inducing multiple waves with additional axotomies did not change the kinetics of degeneration. In contrast, a second phase of calcium influx occurring minutes before fragmentation spread as a wave throughout the axon, entered mitochondria, and was abolished by WldS expression. In live zebrafish, chelating calcium after the first wave, but before the second wave, delayed the progress of fragmentation. In cultured DRG neurons, chelating calcium early in the process of WD did not alter degeneration, but chelating calcium late in WD delayed fragmentation. We propose that a terminal calcium wave is a key instructive component of the axon degeneration program. SIGNIFICANCE STATEMENT Axon degeneration resulting from trauma or neurodegenerative disease can cause devastating deficits in neural function. Understanding the molecular and cellular events that execute axon degeneration is essential for developing treatments to address these conditions. Calcium is known to contribute to axon degeneration, but its temporal requirements in this process have been unclear. Live calcium imaging in severed zebrafish neurons and temporally controlled

Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates

Science.gov (United States)

Skulan, Joseph; DePaolo, Donald J.

1999-01-01

Calcium from bone and shell is isotopically lighter than calcium of soft tissue from the same organism and isotopically lighter than source (dietary) calcium. When measured as the 44Ca/40Ca isotopic ratio, the total range of variation observed is 5.5‰, and as much as 4‰ variation is found in a single organism. The observed intraorganismal calcium isotopic variations and the isotopic differences between tissues and diet indicate that isotopic fractionation occurs mainly as a result of mineralization. Soft tissue calcium becomes heavier or lighter than source calcium during periods when there is net gain or loss of mineral mass, respectively. These results suggest that variations of natural calcium isotope ratios in tissues may be useful for assessing the calcium and mineral balance of organisms without introducing isotopic tracers. PMID:10570137

41 CFR 105-54.304 - Cost guidelines.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Cost guidelines. 105-54.304 Section 105-54.304 Public Contracts and Property Management Federal Property Management... Administration 54-ADVISORY COMMITTEE MANAGEMENT 54.3-Advisory Committee Procedures § 105-54.304 Cost guidelines...

Cardiovascular Effects of Calcium Supplements

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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.

Dietary Calcium Intake and Calcium Supplementation in Hungarian Patients with Osteoporosis

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Gábor Speer

2013-01-01

Full Text Available Purpose. Adequate calcium intake is the basis of osteoporosis therapy—when this proves insufficient, even specific antiosteoporotic agents cannot exert their actions properly. Methods. Our representative survey analyzed the dietary intake and supplementation of calcium in 8033 Hungarian female and male (mean age: 68 years (68.01 (CI95: 67.81–68.21 patients with osteoporosis. Results. Mean intake from dietary sources was 665±7.9 mg (68.01 (CI95: 67.81–68.21 daily. A significant positive relationship could be detected between total dietary calcium intake and lumbar spine BMD (P=0.045, whereas such correlation could not be demonstrated with femoral T-score. Milk consumption positively correlated with femur (P=0.041, but not with lumbar BMD. The ingestion of one liter of milk daily increased the T-score by 0.133. Average intake from supplementation was 558±6.2 mg (68.01 (CI95: 67.81–68.21 daily. The cumulative dose of calcium—from both dietary intake and supplementation—was significantly associated with lumbar (r=0.024, P=0.049, but not with femur BMD (r=0.021, P=0.107. The currently recommended 1000–1500 mg total daily calcium intake was achieved in 34.5% of patients only. It was lower than recommended in 47.8% of the cases and substantially higher in 17.7% of subjects. Conclusions. We conclude that calcium intake in Hungarian osteoporotic patients is much lower than the current recommendation, while routinely applied calcium supplementation will result in inappropriately high calcium intake in numerous patients.

Calcium oxalate stone and gout.

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Marickar, Y M Fazil

2009-12-01

Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P stones patients. The inhibitor urine citrate (P stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

Lumen and calcium characteristics within calcified coronary lesions. Comparison of computed tomography coronary angiography versus intravascular ultrasound.

Science.gov (United States)

Noll, Dariusz; Kruk, Mariusz; Pręgowski, Jerzy; Kaczmarska, Edyta; Kryczka, Karolina; Pracoń, Radosław; Skwarek, Mirosław; Dzielińska, Zofia; Petryka, Joanna; Spiewak, Mateusz; Lubiszewska, Barbara; Norwa-Otto, Bożena; Opolski, Maksymilian; Witkowski, Adam; Demkow, Marcin; Rużyłło, Witold; Kępka, Cezary

2013-01-01

Computed tomography coronary angiography (CTCA) is a diagnostic method used for exclusion of coronary artery disease. However, lower accuracy of CTCA in assessment of calcified lesions is a significant factor impeding applicability of CTCA for assessment of coronary atherosclerosis. To provide insight into lumen and calcium characteristics assessed with CTCA, we compared these parameters to the reference of intravascular ultrasound (IVUS). Two hundred and fifty-two calcified lesions within 97 arteries of 60 patients (19 women, age 63 ±10 years) underwent assessment with both 2 × 64 slice CT (Somatom Definition, Siemens) and IVUS (s5, Volcano Corp.). Coronary lumen and calcium dimensions within calcified lesions were assessed with CTCA and compared to the reference measurements made with IVUS. On average CTCA underestimated mean lumen diameter (2.8 ±0.7 mm vs. 2.9 ±0.8 mm for IVUS), lumen area (6.4 ±3.4 mm(2) vs. 7.0 ±3.7 mm(2) for IVUS, p < 0.001) and total calcium arc (52 ±35° vs. 83 ±54°). However, analysis of tertiles of the examined parameters revealed that the mean lumen diameter, lumen area and calcium arc did not significantly differ between CTCA and IVUS within the smallest lumens (1(st) tertile of mean lumen diameter at 2.1 mm, and 1(st) tertile of lumen area at 3.7 mm(2)) and lowest calcium arc (mean of 40°). Although, on average, CTCA underestimates lumen diameter and area as well as calcium arc within calcified lesions, the differences are not significant within the smallest vessels and calcium arcs. The low diagnostic accuracy of CTCA within calcified lesions may be attributed to high variance and not to systematic error of measurements.

Purification and reconstitution of the calcium antagonist receptor of the voltage-sensitive calcium channel

International Nuclear Information System (INIS)

Curtis, B.M.

1986-01-01

Treatment with digitonin solubilized the calcium antagonist receptor as a stable complex with [ 3 H]nitrendipine from rat brain membranes. The solubilized complex retains allosteric coupling to binding sites for diltiazem, verapamil, and inorganic calcium antagonist sites. The calcium antagonist receptor from cardiac sarcolemma and the transverse-tubule membrane of skeletal muscle is also efficiently solubilized with digitonin and the receptor in all three tissues is a large glycoprotein with a sedimentation coefficient of 20 S. The T-tubule calcium antagonist receptor complex was extensively purified by a combination of chromatography on WGA-Sepharose, ion exchange chromatography, and sedimentation on sucrose gradients to yield preparations estimated to be 41% homogeneous by specific activity and 63% homogeneous by SDS gel electrophoresis. Analysis of SDS gels detect three polypeptides termed α(Mr 135,000), β(Mr 50,000), and γ(Mr 32,000) as noncovalently associated subunits of the calcium antagonist receptor. The α and γ subunits are glycosylated polypeptides, and the molecular weight of the core polypeptides are 108,000 and 24,000 respectively. The calcium antagonist receptor was reconstituted into a phospholipid bilayer by adding CHAPS and exogeneous lipid to the purified receptor followed by rapid detergent removal. This procedure resulted in the incorporation of 45% of the calcium antagonist receptor into closed phospholipid vesicles. Data suggests that the α, β, and γ subunits of the T-tubule calcium antagonist receptor are sufficient to form a functional calcium channel

Why Calcium? How Calcium Became the Best Communicator*

OpenAIRE

Carafoli, Ernesto; Krebs, Joachim

2016-01-01

Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations,...

Calcium-Induced calcium release during action potential firing in developing inner hair cells.

Science.gov (United States)

Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J

2015-03-10

In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

21 CFR 573.260 - Calcium silicate.

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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 not...

21 CFR 573.240 - Calcium periodate.

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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 in...

Calcium chromate process related investigations

International Nuclear Information System (INIS)

Dillard, B.M.

1979-01-01

A pilot plant for production of calcium chromate has been scaled up to a small production facility at the General Electric Neutron Devices Department. In preparation for this scale-up, the process and final product were studied in order to evaluate problems not considered previously. The variables and processes studied included: (1) the determination of optimum drying temperature and time for product analysis; (2) the effect of the grade of lime used as the precipitating agent on the purity of the calcium chromate; (3) product purity when calcium chromate is precipitated by the addition of ammonium chromate to slaked lime; (4) the reagents best suited for cleaning calcium chromate spills; and (5) methods for determining hydroxide ion concentration in calcium chromate. The optimum drying time for the product before analysis is four hours at 600 0 C. Gases evolved at various temperatures during the drying process were carbon dioxide and water vapor. Technical grade lime produced calcium chromate of the highest purity. Both nitric and acetic acids were efficient dissolvers of calcium chromate spills. Direct titration of hydroxide ion with sulfuric acid gave an average recovery of 93% for samples spiked with calcium hydroxide. 1 figure, 17 tables

[The fasting calcium/creatinine ratio in patients with calcium stones and the relation with hypercalciuria and phosphocalcium metabolism].

Science.gov (United States)

Arrabal-Polo, Miguel Ángel; del Carmen Cano-García, María; Arrabal-Martín, Miguel

2016-04-01

To determine the importance of fasting calcium/creatinine ratio in patients with calcium stones and its relation with hypercalciuria and phospho-calcium metabolism. Cross-sectional study including 143 patients divided into two groups according to fasting calcium/creatinine. Group 1: 66 patients (calcium/ creatininecreatinine>0.11). A comparative study is performed between groups including phospho-calcium metabolism parameters and excretion of urinary lithogenic markers. Linear correlation studying calciuria and fasting calcium/ creatinine was performed. SPSS 17.0 statistical analysis software was used, considering p≤0.05. It is noteworthy that group 2 had increased 24 h urine calcium excretion in comparison to group 1 (229.3 vs 158.1; p=0.0001) and calcium/citrate (0.47 vs 0.34; p=0.001). There is a positive and significant correlation between calcium levels in 24 h urine and fasting calcium/creatinine (R=0.455; p=0.0001) and a cutoff is set at 0.127 (sensitivity 72%, specificity 66%) to determine hypercalciuria (>260 mg in 24 h). Increased fasting calcium/creatinine determines increased 24 hours calcium excretion, although the sensitivity and specificity to determine hypercalciuria is not high.

At-Home and Away-from-Home Eating Patterns Influencing Preadolescents' Intake of Calcium-Rich Food as Perceived by Asian, Hispanic and Non-Hispanic White Parents

Science.gov (United States)

Cluskey, Mary; Edlefsen, Miriam; Olson, Beth; Reicks, Marla; Auld, Garry; Bock, Margaret A.; Boushey, Carol J.; Bruhn, Christine; Goldberg, Dena; Misner, Scottie; Wang, Changzheng; Zaghloul, Sahar

2008-01-01

Objective: To explore at-home and away-from-home eating patterns influencing Asian, Hispanic, and non-Hispanic white preadolescents' intake of calcium-rich food from a parental perspective. Design: Individual semistructured interviews. Setting: Home or community site. Participants: Convenience sample (n = 201) of self-reported Asian (n = 54),…

Calcium regulation and Alzheimer’s disease

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Deepthi Rapaka

2014-09-01

Full Text Available Activation of the neuron induces transient fluctuations in [Ca2+]i. This transient rise in [Ca2+]i is dependent on calcium entry via calcium channels and release of calcium from intracellular stores, finally resulting in increase in calcium levels, which activates calcium regulatory proteins to restore the resting calcium levels by binding to the calcium-binding proteins, sequestration into the endoplasmic reticulum and the mitochondria, and finally extrusion of calcium spike potential from the cell by adenosine triphosphate-driven Ca2+ pumps and the Na+/Ca2+ exchanger. Improper regulation of calcium signaling, sequentially, likely contributes to synaptic dysfunction and excitotoxic and/or apoptotic death of the vulnerable neuronal populations. The cognitive decline associated with normal aging is not only due to neuronal loss, but is fairly the result of synaptic connectivity. Many evidences support that Ca2+ dyshomeostasis is implicated in normal brain aging. Thus the chief factor associated with Alzheimer’s disease was found to be increase in the levels of free intracellular calcium, demonstrating that the excessive levels might lead to cell death, which provides a key target for the calcium channel blockers might be used as the neuroprotective agents in Alzheimer’s disease.

21 CFR 184.1207 - Calcium lactate.

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2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactate. 184.1207 Section 184.1207 Food and... Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any... calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of the Food Chemicals...

7 CFR 1780.54 - Technical services.

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2010-01-01

... 7 Agriculture 12 2010-01-01 2010-01-01 false Technical services. 1780.54 Section 1780.54 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF..., Constructing and Inspections § 1780.54 Technical services. Owners are responsible for providing the engineering...

Calcium Occupancy of N-terminal Sites within Calmodulin Induces Inhibition of the Ryanodine Receptor Calcium Release Channel

Energy Technology Data Exchange (ETDEWEB)

Boschek, Curt B; Jones, Terry E; Squier, Thomas C; Bigelow, Diana J

2007-08-01

Calmodulin (CaM) regulates calcium release from intracellular stores in skeletal muscle through its association with the ryanodine receptor (RyR1) calcium release channel, where CaM association enhances channel opening at resting calcium levels and its closing at micromolar calcium levels associated with muscle contraction. A high-affinity CaM-binding sequence (RyRp) has been identified in RyR1, which corresponds to a 30-residue sequence (i.e., K3614 – N3643) located within the central portion of the primary sequence. However, it is currently unclear whether the identified CaM-binding sequence a) senses calcium over the physiological range of calcium-concentrations associated with RyR1 regulation or b) plays a structural role unrelated to the calcium-dependent modulation of RyR1 function. Therefore, we have measured the calcium-dependent activation of the individual domains of CaM in association with RyRp and their relationship to the CaM-dependent regulation of RyR1. These measurements utilize an engineered CaM, permitting the site-specific incorporation of N-(1-pyrene) maleimide at either T34C (PyN-CaM) or T110C (PyC-CaM) in the N- and C-domains, respectively. Consistent with prior measurements, we observe a high-affinity association between both apo- and calcium-activated CaM and RyRp. Upon association with RyRp, fluorescence changes in PyN-CaM or PyC-CaM permit the measurement of the calcium-activation of these individual domains. Fluorescence changes upon calcium-activation of PyC-CaM in association with RyRp are indicative of high-affinity calcium-dependent activation of the C-terminal domain of CaM bound to RyRp at resting calcium levels and the activation of the N-terminal domain at levels of calcium associated cellular activation. In comparison, occupancy of calcium-binding sites in the N-domain of CaM mirrors the calcium-dependence of RyR1 inhibition observed at activating calcium levels, where [Ca]1/2 = 4.3 0.4 μM, suggesting a direct regulation of Ry

28 CFR 54.410 - Comparable facilities.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Comparable facilities. 54.410 Section 54... in Education Programs or Activities Prohibited § 54.410 Comparable facilities. A recipient may provide separate toilet, locker room, and shower facilities on the basis of sex, but such facilities...

7 CFR 989.54 - Marketing policy.

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2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Marketing policy. 989.54 Section 989.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... CALIFORNIA Order Regulating Handling Marketing Policy § 989.54 Marketing policy. (a) Trade demand. On or...

46 CFR 54.30-3 - Introduction.

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2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Introduction. 54.30-3 Section 54.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Mechanical Stress Relief § 54.30-3 Introduction. (a) Large conventional pressure vessels used to transport liquefied...

42 CFR 54.10 - Fiscal accountability.

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2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Fiscal accountability. 54.10 Section 54.10 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS CHARITABLE CHOICE... PROJECTS FOR ASSISTANCE IN TRANSITION FROM HOMELESSNESS GRANTS § 54.10 Fiscal accountability. (a) Religious...

40 CFR 205.54 - Test procedures.

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2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test procedures. 205.54 Section 205.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Medium and Heavy Trucks § 205.54 Test procedures. The procedures described...

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 inhibi...

Calcium microdomains near R-type calcium channels control the induction of presynaptic LTP at parallel fiber to Purkinje cell synapses

Science.gov (United States)

Myoga, Michael H.; Regehr, Wade G.

2011-01-01

R-type calcium channels in postsynaptic spines signal through functional calcium microdomains to regulate a calcium-calmodulin sensitive potassium channel that in turn regulates postsynaptic hippocampal LTP. Here we ask whether R-type calcium channels in presynaptic terminals also signal through calcium microdomains to control presynaptic LTP. We focus on presynaptic LTP at parallel fiber to Purkinje cell synapses in the cerebellum (PF-LTP), which is mediated by calcium/calmodulin-stimulated adenylyl cyclases. Although most presynaptic calcium influx is through N-type and P/Q-type calcium channels, blocking these channels does not disrupt PF-LTP, but blocking R-type calcium channels does. Moreover, global calcium signaling cannot account for the calcium dependence of PF-LTP because R-type channels contribute modestly to overall calcium entry. These findings indicate that within presynaptic terminals, R-type calcium channels produce calcium microdomains that evoke presynaptic LTP at moderate frequencies that do not greatly increase global calcium levels,. PMID:21471358

Cross sections for the reactions 54Fe(n,α)51Cr, 54Fe(n,p)54Mn, and 56Fe(n,p)56Mn

International Nuclear Information System (INIS)

Paulsen, A.; Widera, R.; Arnotte, F.; Liskien, H.

1979-01-01

Ratios of cross sections for the reactions 54 Fe(n,α) 51 Cr, 54 Fe(n,p) 54 Mn, and 56 Fe(n,p) 56 Mn were measured by the activation technique. In the 6- to 10-MeV energy range, quasi-monoenergetic neutrons produced by the D(d,n) source reaction were used, while additional data were obtained between 12 and 17 MeV by use of the T(d,n) source reaction. The cross-section ratios have accuracies between 1.5 and 4.5%. 1 figure, 3 tables

The role of calcium utilization of intestinal flora on urinary calcium excretion

International Nuclear Information System (INIS)

Yurt Lambrecht, F.; Uenak, P.; Kavukcu, S.; Soylu, A.; Tuerkmen, M.; Kasap, B.; Yucesoy, M.; Esen, N.

2005-01-01

Aim: To investigate whether calcium utilization of intestinal flora has any effect on urinary calcium excretion, like oxalate degrading effect of Oxalobacter formigenes. Materials and Methods: The data of urinary calcium excretion examinations were evaluated. 0.1 g/ml of feces samples were implanted in broths. 5 μL of 45 Ca solution was added to the samples and they were incubated for 24 hours at 37 degree C. The amount of bacteriae in the samples was determined as colony forming unit (CFU). 200 μL of the samples were filtrated by 0.45 μm membrane and rinsed by 200 μL pure water. 45 Ca activity ( 45 Ca) of bacteria in the membrane was counted by GM detector for 100 seconds. Then, activity per CFU ( 45 Ca/CFU) was calculated and compared in hypercalciuric (calciuria >4; mg/kg/hour and/or calcium/creatinine ratio>0.21; Group I) and normocalciuric (Group II) patients. Results: Samples of 29 patients with a mean age of 7.50±4.28 (1.5-16) years were evaluated. 11 of them were female (M/F: 18/11). There were 14 patients in Group I and 15 patients in Group II, 45 Ca/CFU was not different for neither aerobic nor anaerobic bacteries between the two groups (p:0.983, p:0.601, respectively). 24-hour urine calcium levels were negatively but not significantly correlated to aerobic and anaerobic 45 Ca/CFU (p:0.079, r:-0.145; p:0.260, r:-0.420, respectively) in hypercalciuric patients. Besides, in normocalciuric patients, 24-hour urine calcium levels were correlated positively to aerobic and negatively to anaerobic 45 Ca/CFU again in an insignificant manner (p:0.509, r: 0.223; p:0623, r:-0.257, respectively). Conclusion: In this, study, similar 45 Ca/CFU levels in both hypercalciuric and normocalciuric patients imply that calcium utilization of intestinal flora does not have a distinct effect on urinary calcium excretion but, although not significant, there was a negative correlation between urine calcium levels and bacterial 45 Ca/CFU levels especially in hypercalciuric

40 CFR 30.54 - Quality assurance.

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2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Quality assurance. 30.54 Section 30.54... NON-PROFIT ORGANIZATIONS Post-Award Requirements Reports and Records § 30.54 Quality assurance. If the... data generation, the grantee shall develop and implement quality assurance practices consisting of...

7 CFR 1700.54 - Electric Program.

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2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false Electric Program. 1700.54 Section 1700.54 Agriculture... GENERAL INFORMATION Loan and Grant Approval Authorities § 1700.54 Electric Program. (a) Administrator: The... Administrator, Electric Program, has the authority to approve the following loans, loan guarantees, and lien...

28 CFR 54.525 - Fringe benefits.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

46 CFR 503.54 - Original classification.

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2010-10-01

... 46 Shipping 9 2010-10-01 2010-10-01 false Original classification. 503.54 Section 503.54 Shipping... Program § 503.54 Original classification. (a) No Commission Member or employee has the authority to... classification, it shall be sent to the appropriate agency with original classification authority over the...

Movement of calcium signals and calcium-binding proteins: firewalls, traps and tunnels.

Science.gov (United States)

Barrow, S L; Sherwood, M W; Dolman, N J; Gerasimenko, O V; Voronina, S G; Tepikin, A V

2006-06-01

In the board game 'Snakes and Ladders', placed on the image of a pancreatic acinar cell, calcium ions have to move from release sites in the secretory region to the nucleus. There is another important contraflow - from calcium entry channels in the basal part of the cell to ER (endoplasmic reticulum) terminals in the secretory granule region. Both transport routes are perilous as the messenger can disappear in any place on the game board. It can be grabbed by calcium ATPases of the ER (masquerading as a snake but functioning like a ladder) and tunnelled through its low buffering environment, it can be lured into the whirlpools of mitochondria uniporters and forced to regulate the tricarboxylic acid cycle, and it can be permanently placed inside the matrix of secretory granules and released only outside the cell. The organelles could trade calcium (e.g. from the ER to mitochondria and vice versa) almost depriving this ion the light of the cytosol and noble company of cytosolic calcium buffers. Altogether it is a rich and colourful story.

7 CFR 906.54 - Effective time.

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2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Effective time. 906.54 Section 906.54 Agriculture... RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Miscellaneous Provisions § 906.54 Effective time. The provisions of this subpart, or any amendment thereto, shall become effective at such time as the...

Vitamin D, PTH, and calcium in relation to survival following prostate cancer.

Science.gov (United States)

Brändstedt, Johan; Almquist, Martin; Manjer, Jonas; Malm, Johan

2016-05-01

Epidemiological studies suggest that low levels of vitamin D constitute a risk factor for prostate cancer. However, the results are conflicting, perhaps because prostate cancer is a very heterogeneous disease. More recent studies have focused on cancer progression and mortality. Vitamin D is closely related to both calcium metabolism and parathyroid hormone (PTH) levels, and all three factors have been implicated in prostate cancer. We examined the associations between pre-diagnostic serum levels of vitamin D (25OHD), PTH, and calcium and mortality among 943 participants within the Malmö Diet and Cancer Study, who were diagnosed with prostate cancer. The mean time from diagnosis until the end of followup was 9.1 years (SD 4.5), and the mean time from inclusion until end of follow-up was 16.6 years (SD 4.9). The analytes were divided into quartiles, and the risk of death from prostate cancer was analyzed using Cox proportional hazard analysis, yielding hazards ratios (HR) with 95 % confidence intervals. The models were adjusted for season and year of inclusion, age at baseline, age at diagnosis, body mass index (BMI), and tumor characteristics (TNM and Gleason score). We observed a trend toward a lower prostate-specific mortality with 25OHD >85 nmol/L in the unadjusted analysis. This became statistically significantly in the third quartile of 25OHD (85-102 nmol/L) compared to the first (L), HR 0.54 (0.34-0.85) when adjusting for age, time of inclusion, and BMI. The association was further strengthened when adjusted for age at diagnosis, Gleason score, and TNM classification with a HR in Q3 0.36 (0.22-0.60). p for trend was 0.03. Regarding calcium, there was a significantly lower HR for the second quartile (2.35-2.39 mmol/L) compared to the first (≤2.34 mmol/L) with a HR of 0.54 (0.32-0.86) in the unadjusted analysis. However, this association disappeared when adjusting for tumor characteristics. There were no associations between levels of PTH and prostate cancer

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

Science.gov (United States)

Dixit, Ajay Kumar; Jayabaskaran, Chelliah

2015-05-01

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

29 CFR 1918.54 - Rigging gear.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees from...

7 CFR 1000.54 - Equivalent price.

Science.gov (United States)

2010-01-01

... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price or...

Calcium transport in turtle bladder

International Nuclear Information System (INIS)

Sabatini, S.; Kurtzman, N.A.

1987-01-01

Unidirectional 45 Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J net Ca ) was secretory (serosa to mucosa). Ouabain reversed J net Ca to an absorptive flux. Amiloride reduced both fluxes such that J net Ca was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J net Ca decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J net Ca was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45 Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca 2+ -ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na + -K + -ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

Calcium in Urine Test

Science.gov (United States)

... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Calcium, Serum; Calcium and Phosphates, Urine; ...

Effects of extracellular calcium on calcium transport during hyperthermia of tumor cells.

Science.gov (United States)

Anghileri, L J; Marcha, C; Crone-Escanyé, M C; Robert, J

1985-08-01

The effects of different concentrations of extracellular ion calcium on the transport of calcium by tumor cells have been studied by means of the uptake of radiocalcium. Tumor cells incubated at 45 degrees C take up 4-10 times the amount of radioactivity incorporated by cells incubated at 37 degrees C. The difference is still greater (up to 100 times) for the intracellular incorporation as assessed by elimination of the membrane-bound calcium by EGTA treatment. The possible mechanisms involved in this differential behavior are discussed.

21 CFR 172.410 - Calcium silicate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely...

Relative biological activity of amorphous calcium and calcium-magnesium phosphates

International Nuclear Information System (INIS)

Silina, E.N.; Kunitsa, T.N.; Shuslikova, E.S.; Griggs, J.; Levchenko, L.V.; Karjaubaeva, R.A.; Sinyayev, V.A.

2005-01-01

Three amorphous calcium and calcium-magnesium phosphates that are close on composition to mineral basis of the bone tissues are compared on bioactivity in the given article. Properties of the hydrated substances produced from water solutions and their derivations, which are formed due to thermal treatment, are discussed here. As a detector of bioactivity was used microbial culture E-Coli. [author

40 CFR 68.54 - Training.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Training. 68.54 Section 68.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CHEMICAL... operator may certify in writing that the employee has the required knowledge, skills, and abilities to...

The effects of excess calcium on the handling and mechanical properties of hydrothermal derived calcium phosphate bone cement

Science.gov (United States)

Razali, N. N.; Sukardi, M. A.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.

2018-01-01

The objective of this study is to determine the effects of excess calcium on the handling and mechanical properties of hydrothermal derived calcium phosphate cement (CPC) for bone filling applications. Hydroxyapatite powder was synthesized via hydrothermal method using calcium oxide, CaO and ammonium dihydrogen phosphate, NH4H2PO4 as the calcium and phosphorus precursors respectively. The effects of calcium excess were evaluated by varying the CaO content at 0, 5 and 15 mole %. The precursors were then refluxed in distilled water at 90-100°C and dried overnight until the calcium phosphate powder was formed. CPC was then produced by mixing the synthesized powder with distilled water at the powder-to-liquid (P/L) ratio of 1.5. The result from the morphological properties of CPC shows the increase in agglomeration and particles size with 5 mole % of calcium excess but decreased with 15 mole % of calcium excess in CPC. This result was in agreement with the compressive strength result where the CPC increased its strength with 5 mole % of calcium excess but reduced with 15 mole % of calcium excess. The excess in calcium precursor also significantly improved the setting time but reduced the injectability of CPC.

Association of calcium sensing receptor polymorphisms at rs1801725 with circulating calcium in breast cancer patients.

Science.gov (United States)

Wang, Li; Widatalla, Sarrah E; Whalen, Diva S; Ochieng, Josiah; Sakwe, Amos M

2017-08-02

Breast cancer (BC) patients with late-stage and/or rapidly growing tumors are prone to develop high serum calcium levels which have been shown to be associated with larger and aggressive breast tumors in post and premenopausal women respectively. Given the pivotal role of the calcium sensing receptor (CaSR) in calcium homeostasis, we evaluated whether polymorphisms of the CASR gene at rs1801725 and rs1801726 SNPs in exon 7, are associated with circulating calcium levels in African American and Caucasian control subjects and BC cases. In this retrospective case-control study, we assessed the mean circulating calcium levels, the distribution of two inactivating CaSR SNPs at rs1801725 and rs1801726 in 199 cases and 384 age-matched controls, and used multivariable regression analysis to determine whether these SNPs are associated with circulating calcium in control subjects and BC cases. We found that the mean circulating calcium levels in African American subjects were higher than those in Caucasian subjects (p calcium levels were higher in BC cases compared to control subjects (p calcium levels in BC patients were independent of race. We also show that in BC cases and control subjects, the major alleles at rs1801725 (G/T, A986S) and at rs1801726 (C/G, Q1011E) were common among Caucasians and African Americans respectively. Compared to the wild type alleles, polymorphisms at the rs1801725 SNP were associated with higher calcium levels (p = 0.006) while those at rs1801726 were not. Using multivariable linear mixed-effects models and adjusting for age and race, we show that circulating calcium levels in BC cases were associated with tumor grade (p = 0.009), clinical stage (p = 0.003) and more importantly, with inactivating mutations of the CASR at the rs1801725 SNP (p = 0.038). These data suggest that decreased sensitivity of the CaSR to calcium due to inactivating polymorphisms at rs1801725, may predispose up to 20% of BC cases to high circulating calcium

Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

International Nuclear Information System (INIS)

Christensen, Hilbert

1962-12-01

By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca 9 Sr(PO 4 ) 6 (OH) 2 - CaSr 9 (PO 4 ) 6 (OH) 2 . The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

9 CFR 3.54 - Feeding.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feeding. 3.54 Section 3.54 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE ANIMAL WELFARE STANDARDS Specifications for the Humane Handling, Care, Treatment and Transportation of Rabbits Animal...

32 CFR 651.54 - Introduction.

Science.gov (United States)

2010-07-01

... 32 National Defense 4 2010-07-01 2010-07-01 true Introduction. 651.54 Section 651.54 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY... Introduction. (a) Protection of the environment is an Army priority, no matter where the Army actions are...

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

Science.gov (United States)

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

2017-12-13

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

Dietary calcium but not elemental calcium from supplements is associated with body composition and obesity in Chinese women.

Directory of Open Access Journals (Sweden)

Lina Huang

Full Text Available We assessed whether dietary calcium intake or calcium supplements associated with body composition and obesity in a Chinese population.A cross-sectional survey was performed in a population of 8940, aged 20 to 74 y. 8127 participants responded (90.9%. Height, weight, fat mass (FM, waist circumference (WC and hip circumference were measured. Obesity definition: body mass index (BMI ≥28 kg/m(2 (overall obesity; WC ≥85 cm for men or ≥80 cm for women (abdominal obesity І and waist hip ratio (WHR ≥0.90 for men or ≥0.85 for women (abdominal obesity П. The data on dietary calcium and calcium supplements were collected using food-frequency questionnaire and self-report questionnaire. Multivariate linear and multivariable logistic regressions were used to examine the associations between dietary calcium intake or calcium supplements and body composition and obesity.The average dietary calcium intake of all subjects was 430 mg/d. After adjusting for potential confounding factors, among women only, negative associations were observed between habitual dietary calcium intake and four measures of body composition (β, -0.086, P0.05. Similarly, among both men and women, we did not observe significant associations between calcium supplements and any measures of body composition or abdominal obesity (P>0.05.Dietary calcium from food rather than elemental calcium from calcium supplements has beneficial effects on the maintenance of body composition and preventing abdominal obesity in Chinese women.

Calcium levels and calcium: available phosphorus ratios in diets for white egg layers from 42 to 58 weeks of age

Directory of Open Access Journals (Sweden)

Silvana Marques Pastore

2012-12-01

Full Text Available The experiment was conducted to determine the nutritional requirement of calcium and the best calcium:available phosphorus ratio for commercial layers at the post-laying peak. A total of 324 Hy-Line W-36 laying hens were utilized in the period from 42 to 58 weeks of age, distributed in a completely randomized design in a 3 × 3 factorial arrangement, composed of three levels of calcium (39, 42 and 45 g/kg and three calcium:phosphorus ratios (12.12:1; 10.53:1; and 9.30:1, totaling nine treatments with six replications and six birds per experimental unit. There was no significant effect from the calcium levels × calcium:phosphorus ratio interaction for any of the variables studied. The calcium levels and the calcium:phosphorus ratios did not affect the variables performance or egg and bone quality. At the evaluation of the calcium:phosphorus balance, as the levels of calcium of the diet were raised, the intake of calcium and phosphorus and the contents of mineral matter and calcium in the excreta increased linearly, and the retention of calcium by birds decreased linearly. With the reduction of the calcium:phosphorus ratios of the diet, intake, retention and excretion of phosphorus by layers increased. Diets containing calcium at 39 g/kg and a calcium:phosphorus ratio of 12.12:1, corresponding to an increase in calcium of 3.51 g/bird/day and available phosphorus of 289 mg/bird/day, meet the requirements of calcium and available phosphorus of white egg layers in the period from 42 to 58 weeks of age.

Exopolysaccharides regulate calcium flow in cariogenic biofilms

Science.gov (United States)

Varenganayil, Muth M.; Decho, Alan W.

2017-01-01

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

Exopolysaccharides regulate calcium flow in cariogenic biofilms.

Directory of Open Access Journals (Sweden)

Monika Astasov-Frauenhoffer

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

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 ...

The Plasma Membrane Calcium Pump

Science.gov (United States)

Rasmussen, H.

1983-01-01

Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

The Role of Calcium in Osteoporosis

Science.gov (United States)

Arnaud, C. D.; Sanchez, S. D.

1991-01-01

Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25 to 30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years). Starting at age 40 to 50, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D2. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. Generally, the strongest risk factors for osteoporosis are uncontrollable (e.g., sex, age, and race) or less controllable (e.g., disease and medications). However, several factors such as diet, physical activity, cigarette smoking, and alcohol use are lifestyle related and can be modified to help reduce the risk of osteoporosis.

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

28 CFR 54.220 - Admissions.

Science.gov (United States)

2010-07-01

... Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN...) Admissions to educational institutions prior to June 24, 1973, are not covered by these Title IX regulations... §§ 54.300 through 54.310, each administratively separate unit shall be deemed to be an educational...

Calcium and magnesium determination

International Nuclear Information System (INIS)

Bhattacharya, S.K.

1982-01-01

The roles of calcium and magnesium in human health and disease have been extensively studied. Calcium and magnesium have been determined in biological specimens by atomic absorption spectroscopy using stiochiometric nitrous oxide-acetylene flame

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

International Nuclear Information System (INIS)

Ribovich, M.L.; DeLuca, H.F.

1978-01-01

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 D 3 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 D 3 , 24,25-dihydroxyvitamin D 3 , 1,25-dihydroxyvitamin D 3 , 25,26-dihydroxyvitamin D 3 , and 1,24,25-trihydroxyvitamin D 3 ), several new and unidentified metabolites were found. In addition to 1,25-dihydroxyvitamin D 3 and 1,24,25-trihydroxyvitamin D 3 , 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

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...

Hydrolytic conversion of amorphous calcium phosphate into apatite accompanied by sustained calcium and orthophosphate ions release

Energy Technology Data Exchange (ETDEWEB)

Niu, Xufeng, E-mail: nxf@buaa.edu.cn [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China); BUAA Research Institute, Guangzhou 510530 (China); Research Institute of Beihang University in Shenzhen, Shenzhen 518057 (China); Chen, Siqian; Tian, Feng; Wang, Lizhen [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China); Feng, Qingling [State Key Laboratory of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Fan, Yubo, E-mail: yubofan@buaa.edu.cn [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China)

2017-01-01

The aim of this study is to investigate the calcium and orthophosphate ions release during the transformation of amorphous calcium phosphate (ACP) to hydroxyapatite (HA) in aqueous solution. The ACP is prepared by a wet chemical method and further immersed in the distilled water for various time points till 14 d. The release of calcium and orthophosphate ions is measured with calcium and phosphate colorimetric assay kits, respectively. The transition of ACP towards HA is detected by x-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR). The results indicate that the morphological conversion of ACP to HA occurs within the first 9 h, whereas the calcium and orthophosphate ions releases last for over 7 d. Such sustained calcium and orthophosphate ions release is very useful for ACP as a candidate material for hard tissue regeneration. - Highlights: • ACP is prepared using a wet chemical method. • The conversion of crystal morphology and structure occurs mainly within the initial 9 h. • The calcium and orthophosphate ions release sustains over 14 d.

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

21 CFR 184.1229 - Calcium stearate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as...

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, or...

21 CFR 184.1193 - Calcium chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium chloride. 184.1193 Section 184.1193 Food... Specific Substances Affirmed as GRAS § 184.1193 Calcium chloride. (a) Calcium chloride (CaCl2·2H2O, CAS Reg. No. 10035-04-8) or anhydrous calcium chloride (CaCl2, CAS Reg. No. 10043-52-4) may be commercially...

A Crash Course in Calcium Channels.

Science.gov (United States)

Zamponi, Gerald W

2017-12-20

Much progress has been made in understanding the molecular physiology and pharmacology of calcium channels. Recently, there have been tremendous advances in learning about calcium channel structure and function through crystallography and cryo-electron microscopy studies. Here, I will give an overview of our knowledge about calcium channels, and highlight two recent studies that give important insights into calcium channel structure.

Fermentation of calcium-fortified soymilk with Lactobacillus: effects on calcium solubility, isoflavone conversion, and production of organic acids.

Science.gov (United States)

Tang, A L; Shah, N P; Wilcox, G; Walker, K Z; Stojanovska, L

2007-11-01

The objective of this study was to enhance calcium solubility and bioavailability from calcium-fortified soymilk by fermentation with 7 strains of Lactobacillus, namely, L. acidophilus ATCC 4962, ATCC33200, ATCC 4356, ATCC 4461, L. casei ASCC 290, L. plantarum ASCC 276, and L. fermentum VRI-003. The parameters that were used are viability, pH, calcium solubility, organic acid, and biologically active isoflavone aglycone content. Calcium-fortified soymilk made from soy protein isolate was inoculated with these probiotic strains, incubated for 24 h at 37 degrees C, then stored for 14 d at 4 degrees C. Soluble calcium was measured using atomic absorption spectrophotometry (AA). Organic acids and bioactive isoflavone aglycones, including diadzein, genistein, and glycetein, were measured using HPLC. Viability of the strains in the fermented calcium-fortified soymilk was > 8.5 log(10) CFU/g after 24 h fermentation and this was maintained for 14-d storage at 4 degrees C. After 24 h, there was a significant increase (P casei ASCC 290 demonstrated the highest increase with 89.3% and 87.0% soluble calcium after 24 h, respectively. The increase in calcium solubility observed was related to lowered pH associated with production of lactic and acetic acids. Fermentation significantly increased (P < 0.05) the level of conversion of isoflavones into biologically active aglycones, including diadzein, genistein, and glycetein. Our results show that fermenting calcium-fortified soymilk with the selected probiotics can potentially enhance the calcium bioavailability of calcium-fortified soymilk due to increased calcium solubility and bioactive isoflavone aglycone enrichment.

Intracellular sphingosine releases calcium from lysosomes.

Science.gov (United States)

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

2015-11-27

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

21 CFR 640.54 - Processing.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Processing. 640.54 Section 640.54 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) BIOLOGICS ADDITIONAL... storage system. A combination of dry ice and organic solvent may be used for freezing: Provided, That the...

15 CFR 923.54 - Mediation.

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Mediation. 923.54 Section 923.54... Mediation. (a) Section 307(h) of the Act provides for mediation of serious disagreement between any Federal... cases, mediation by the Secretary, with the assistance of the Executive Office of the President, may be...

Impaired body calcium metabolism with low bone density and compensatory colonic calcium absorption in cecectomized rats

NARCIS (Netherlands)

Jongwattanapisan, P.; Suntornsaratoon, P.; Wongdee, K.; Dorkkam, N.; Krishnamra, N.; Charoenphandhu, N.

2012-01-01

An earlier study reported that cecal calcium absorption contributes less than 10% of total calcium absorbed by the intestine, although the cecum has the highest calcium transport rate compared with other intestinal segments. Thus, the physiological significance of the cecum pertaining to body

BLENDED CALCIUM ALUMINATE-CALCIUM SULFATE CEMENT-BASED GROUT FOR P-REACTOR VESSEL IN-SITU DECOMMISSIONING

Energy Technology Data Exchange (ETDEWEB)

Langton, C.; Stefanko, D.

2011-03-10

The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

Timing of the calcium intake and effect of calcium deficiency on behaviour and egg laying in captive great tits, Parus major.

Science.gov (United States)

Graveland, J; Berends, A E

1997-01-01

The calcium demand of egg-laying birds is much higher than in other vertebrates during reproduction. We showed elsewhere that a low level of calcium availability can greatly affect the eggshell quality and reproduction of free-living passerines. However, there are few data on calcium demand and calcium intake in relation to egg laying and behaviour and egg-laying performance under conditions of calcium shortage in nondomesticated birds. We examined these aspects in an experiment with captive great tits, Parus major, on a diet deficient in calcium, with or without snail shells as an additional calcium source. More than 90% of the calcium intake for egg production took place during the egg-laying period. Females ingested about 1.7 times as much calcium as they deposited in eggshells. Removing the snail shells after the first egg resulted in eggshell defects and interruptions of laying after 1-3 d. Females without snail shells doubled their searching effort and started to burrow in the soil and to eat sand, small stones, and their own eggs. Most calcium was consumed in the evening, probably to supplement the calcium available from the medullary bone with an additional calcium source in the gut during eggshell formation. The results demonstrated that eggshell formation requires accurate timing of the calcium intake and that obtaining sufficient calcium is time-consuming, even in calcium-rich environments. These factors pertaining to calcium intake greatly affect the ability of birds to collect sufficient calcium for eggshell formation in calcium-poor areas.

Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

Directory of Open Access Journals (Sweden)

Łuczka Kinga

2016-06-01

Full Text Available Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

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 ...

Calcium-sensing beyond neurotransmitters

DEFF Research Database (Denmark)

Gustavsson, Natalia; Han, Weiping

2009-01-01

Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most....... Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems....... synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin-calcium-sensor paradigm, that is, members of the synaptotagmin family function...... as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion...

Calcium carboorthovanadate - a new compound with the apa

International Nuclear Information System (INIS)

Slobodin, B.V.; Dmitrieva, O.I.; Fotiev, A.A.

1977-01-01

Data on calcium carboorthovanadate, Ca 10 (VO 4 ) 6 CO 3 , a new compound with an appatite structure based on calcium orthovanadate, are reported. The synthesis has been conducted in a stoichiometric mixture of finely ground calcium carbonate and calcium orthovanadate. It is found that calcium carboorthovanadate belongs to the hexagonal syngony and has an apatite structure. An analysis of the infrared spectra of initial compounds and calcium carboorthovanadate confirmed the presence of carbonate (CO 3 ) 2- and orthovanadate (VO 4 ) 3 groupings in the latter. On heating in air, beginning with 450 deg C calcium carboorthovanadate decomposes at a slow rate into calcium oxide, calcium orthovanadate, and carbon dioxide

21 CFR 54.2 - Definitions.

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2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Definitions. 54.2 Section 54.2 Food and Drugs FOOD... or device in humans submitted in a marketing application or reclassification petition subject to this... $25,000, exclusive of the costs of conducting the clinical study or other clinical studies, (e.g., a...

17 CFR 201.54 - Settlement.

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2010-04-01

... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Settlement. 201.54 Section 201... Regulations Pertaining to the Equal Access to Justice Act § 201.54 Settlement. The applicant and counsel for the Office or Division of the Commission may agree on a proposed settlement of the award before final...

Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

Energy Technology Data Exchange (ETDEWEB)

Christensen, Hilbert

1962-12-15

By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca{sub 9}Sr(PO{sub 4}){sub 6}(OH){sub 2} - CaSr{sub 9}(PO{sub 4}){sub 6}(OH){sub 2}. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice.

21 CFR 184.1195 - Calcium citrate.

Science.gov (United States)

2010-04-01

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

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

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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.

Electrophoretic mobility shift in native gels indicates calcium-dependent structural changes of neuronal calcium sensor proteins.

Science.gov (United States)

Viviano, Jeffrey; Krishnan, Anuradha; Wu, Hao; Venkataraman, Venkat

2016-02-01

In proteins of the neuronal calcium sensor (NCS) family, changes in structure as well as function are brought about by the binding of calcium. In this article, we demonstrate that these structural changes, solely due to calcium binding, can be assessed through electrophoresis in native gels. The results demonstrate that the NCS proteins undergo ligand-dependent conformational changes that are detectable in native gels as a gradual decrease in mobility with increasing calcium but not other tested divalent cations such as magnesium, strontium, and barium. Surprisingly, such a gradual change over the entire tested range is exhibited only by the NCS proteins but not by other tested calcium-binding proteins such as calmodulin and S100B, indicating that the change in mobility may be linked to a unique NCS family feature--the calcium-myristoyl switch. Even within the NCS family, the changes in mobility are characteristic of the protein, indicating that the technique is sensitive to the individual features of the protein. Thus, electrophoretic mobility on native gels provides a simple and elegant method to investigate calcium (small ligand)-induced structural changes at least in the superfamily of NCS proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

The Risks and Benefits of Calcium Supplementation

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Chan Soo Shin

2015-03-01

Full Text Available The association between calcium supplementation and adverse cardiovascular events has recently become a topic of debate due to the publication of two epidemiological studies and one meta-analysis of randomized controlled clinical trials. The reports indicate that there is a significant increase in adverse cardiovascular events following supplementation with calcium; however, a number of experts have raised several issues with these reports such as inconsistencies in attempts to reproduce the findings in other populations and questions concerning the validity of the data due to low compliance, biases in case ascertainment, and/or a lack of adjustment. Additionally, the Auckland Calcium Study, the Women's Health Initiative, and many other studies included in the meta-analysis obtained data from calcium-replete subjects and it is not clear whether the same risk profile would be observed in populations with low calcium intakes. Dietary calcium intake varies widely throughout the world and it is especially low in East Asia, although the risk of cardiovascular events is less prominent in this region. Therefore, clarification is necessary regarding the occurrence of adverse cardiovascular events following calcium supplementation and whether this relationship can be generalized to populations with low calcium intakes. Additionally, the skeletal benefits from calcium supplementation are greater in subjects with low calcium intakes and, therefore, the risk-benefit ratio of calcium supplementation is likely to differ based on the dietary calcium intake and risks of osteoporosis and cardiovascular diseases of various populations. Further studies investigating the risk-benefit profiles of calcium supplementation in various populations are required to develop population-specific guidelines for individuals of different genders, ages, ethnicities, and risk profiles around the world.

Does dietary calcium interact with dietary fiber against colorectal cancer? A case-control study in Central Europe.

Science.gov (United States)

Galas, Aleksander; Augustyniak, Malgorzata; Sochacka-Tatara, Elzbieta

2013-10-04

An unfavorable trend of increasing rates of colorectal cancer has been observed across modern societies. In general, dietary factors are understood to be responsible for up to 70% of the disease's incidence, though there are still many inconsistencies regarding the impact of specific dietary items. Among the dietary minerals, calcium intake may play a crucial role in the prevention. The purpose of this study was to assess the effect of intake of higher levels of dietary calcium on the risk of developing of colorectal cancer, and to evaluate dose dependent effect and to investigate possible effect modification. A hospital based case-control study of 1556 patients (703 histologically confirmed colon and rectal incident cases and 853 hospital-based controls) was performed between 2000-2012 in Krakow, Poland. The 148-item semi-quantitative Food Frequency Questionnaire to assess dietary habits and level of nutrients intake was used. Data regarding possible covariates was also collected. After adjustment for age, gender, education, consumption of fruits, raw and cooked vegetables, fish, and alcohol, as well as for intake of fiber, vitamin C, dietary iron, lifetime recreational physical activity, BMI, smoking status, and taking mineral supplements, an increase in the consumption of calcium was associated with the decrease of colon cancer risk (OR = 0.93, 95% CI: 0.89-0.98 for every 100 mg Ca/day increase). Subjects consumed >1000 mg/day showed 46% decrease of colon cancer risk (OR = 0.54, 95% CI: 0.35-0.83). The effect of dietary calcium was modified by dietary fiber (p for interaction =0.015). Finally, consistent decrease of colon cancer risk was observed across increasing levels of dietary calcium and fiber intake. These relationships were not proved for rectal cancer. The study confirmed the effect of high doses of dietary calcium against the risk of colon cancer development. This relationship was observed across different levels of dietary fiber, and the

Thermoluminescence of calcium-based phosphors

International Nuclear Information System (INIS)

Sunta, C.M.

1985-01-01

The paper reviews the thermoluminescence (TL) properties of calcium fluoride, calcium sulphate and calcium carbonate phosphors. In the case of the calcium fluoride mineral phosphor the main emitter of TL is the cerium impurity. Based on the TL emission spectra, two types of Ce 3+ centres can be easily distinguished; those associated with O 2- compensating ion and those which have either no local compensators or are associated with F - interstitial ions at the adjacent vacant body centre position. The spectra undergo remarkable changes at high doses. Such changes are associated with the probabilities of charge trapping at different types of traps and also with the probabilities of recombination at different types of luminescent centres. Some of the traps and recombination centres are spatially associated while others are distributed randomly. In calcium carbonate mineral, Mn 2+ is invariably the emitting impurity. Mn 2+ can be used as an efficient dopant for TL emission in all the three calcium based TL phosphors. A co-dopant like Ce 3+ intensifies the luminescence yield from Mn 2+ . Models of different types of electron and hole trapping centres are given. (author)

40 CFR 262.54 - Special manifest requirements.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Special manifest requirements. 262.54 Section 262.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Exports of Hazardous Waste § 262.54 Special...

Calcium channel blockers and Alzheimer's disease★

Science.gov (United States)

Tan, Yi; Deng, Yulin; Qing, Hong

2012-01-01

Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary 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 involved in Alzheimer's disease therapy. PMID:25767489

Short communication: Urinary oxalate and calcium excretion by dogs and cats diagnosed with calcium oxalate urolithiasis

NARCIS (Netherlands)

Dijcker, J.C.; Kummeling, A.; Hagen-Plantinga, E.A.; Hendriks, W.H.

2012-01-01

Introduction Urine concentrations of oxalate and calcium play an important role in calcium oxalate (CaOx) urolith formation in dogs and cats, with high excretions of both substances increasing the chance of CaOx urolithiasis. In 17 CaOx-forming dogs, urine calcium:creatinine ratio (Ca:Cr) was found

Contracture of Slow Striated Muscle during Calcium Deprivation

Science.gov (United States)

Irwin, Richard L.; Hein, Manfred M.

1963-01-01

When deprived of calcium the slow striated muscle fibers of the frog develop reversible contractures in either hypertonic or isotonic solutions. While calcium deprivation continues because of a flowing calcium-free solution the muscles relax slowly and completely. Restoration of calcium during contracture relaxes the muscle promptly to initial tension. When relaxed during calcium lack the return of calcium does not change tension and the muscle stays relaxed. When contractures are induced by solutions containing small amounts of calcium relaxation does not occur or requires several hours. The rate of tension development depends upon the rate at which calcium moves outward since the contractures develop slower in low concentrations of calcium and are absent or greatly slowed in a stagnant calcium-free solution. Withdrawal of calcium prevents the contractile responses to ACh, KCl, or electrical stimulation through the nerve. Muscles return to their original excitability after calcium is restored. Origin of the contractures is unrelated to nerve activity since they are maximal during transmission failure from calcium lack, occur in denervated muscles, and are not blocked by high concentrations of d-tubocurarine, procaine, or atropine. The experiments also indicate that the contractures do not originate from repetitive activity of muscle membranes. The findings are most simply explained by relating the outward movement of calcium as a link for initiating contraction in slow type striated muscle. PMID:14065284

Rapid screening assay for calcium bioavailability studies

International Nuclear Information System (INIS)

Luhrsen, K.R.; Hudepohl, G.R.; Smith, K.T.

1986-01-01

Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium ( 47 Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO 3 . In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47 Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

Calcium movements and the cellular basis of gravitropism

Science.gov (United States)

Roux, S. J.; Biro, R. L.; Hale, C. C.

An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.

Plasma concentration of ionized calcium in healthy iguanas.

Science.gov (United States)

Dennis, P M; Bennett, R A; Harr, K E; Lock, B A

2001-08-01

To measure plasma concentration of ionized calcium in healthy green iguanas. Prospective study. 9 juvenile and 21 (10 male, 11 female) adult iguanas. Blood samples were obtained from each iguana, and plasma calcium, glucose, phosphorus, uric acid, total protein, albumin, globulin, potassium, and ionized calcium concentrations, aspartate transaminase (AST) activity, and pH were measured. Heparinized blood was used for measurement of ionized calcium concentration and blood pH. A CBC was also performed to assess the health of the iguanas. Significant differences were not detected among the 3 groups (juveniles, males, and females) with regard to ionized calcium concentration. Mean ionized calcium concentration measured in blood was 1.47 +/- 0.105 mmol/L. Significant differences were detected between juveniles and adults for values of phosphorus, glucose, total protein, albumin, globulin, and AST activity. Ionized calcium concentration provides a clinical measurement of the physiologically active calcium in circulation. Evaluation of physiologically active calcium in animals with suspected calcium imbalance that have total plasma calcium concentrations within reference range or in gravid animals with considerably increased total plasma calcium concentrations is vital for determining a therapeutic plan. Accurate evaluation of calcium status will provide assistance in the diagnosis of renal disease and seizures and allow for better evaluation of the health status of gravid female iguanas.

Effect of calcium chloride treatments on calcium content, anthracnose severity and antioxidant activity in papaya fruit during ambient storage.

Science.gov (United States)

Madani, Babak; Mirshekari, Amin; Yahia, Elhadi

2016-07-01

There have been no reports on the effects of preharvest calcium application on anthracnose disease severity, antioxidant activity and cellular changes during ambient storage of papaya, and therefore the objective of this study was to investigate these effects. Higher calcium concentrations (1.5 and 2% w/v) increased calcium concentration in the peel and pulp tissues, maintained firmness, and reduced anthracnose incidence and severity. While leakage of calcium-treated fruit was lower for 1.5 and 2% calcium treatments compared to the control, microscopic results confirmed that pulp cell wall thickness was higher after 6 days in storage, for the 2% calcium treatment compared to the control. Calcium-treated fruit also had higher total antioxidant activity and total phenolic compounds during storage. Calcium chloride, especially at higher concentrations, is effective in maintaining papaya fruit quality during ambient storage. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

46 CFR 54.25-5 - Corrosion allowance.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Corrosion allowance. 54.25-5 Section 54.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-5 Corrosion allowance. The corrosion allowance...

42 CFR 54a.10 - Fiscal accountability.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Fiscal accountability. 54a.10 Section 54a.10 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS CHARITABLE CHOICE... PREVENTION AND TREATMENT SERVICES § 54a.10 Fiscal accountability. (a) Religious organizations that receive...

46 CFR 111.54-3 - Remote control.

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2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Remote control. 111.54-3 Section 111.54-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Circuit Breakers § 111.54-3 Remote control. Remotely controlled circuit breakers must have local...

47 CFR 54.519 - State telecommunications networks.

Science.gov (United States)

2010-10-01

... § 54.502) on behalf of eligible schools and libraries (as described in § 54.501) or consortia that... providing such services to eligible schools, libraries, and consortia including those entities. [63 FR 2131... (CONTINUED) UNIVERSAL SERVICE Universal Service Support for Schools and Libraries § 54.519 State...

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

Science.gov (United States)

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

2017-10-01

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

Presynaptic calcium signalling in cerebellar mossy fibres

DEFF Research Database (Denmark)

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

2010-01-01

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 tetrodotoxin (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 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...

Calcium Chloride and Calcium Gluconate in Neonatal Parenteral Nutrition Solutions without Cysteine: Compatibility Studies Using Laser Light Obscuration Methodology

Directory of Open Access Journals (Sweden)

Robert K. Huston

2018-02-01

Full Text Available There are no compatibility studies for neonatal parenteral nutrition solutions without cysteine containing calcium chloride or calcium gluconate using light obscuration as recommended by the United States Pharmacopeia (USP. The purpose of this study was to do compatibility testing for solutions containing calcium chloride and calcium gluconate without cysteine. Solutions of TrophAmine and Premasol (2.5% amino acids, containing calcium chloride or calcium gluconate were compounded without cysteine. Solutions were analyzed for particle counts using light obscuration. Maximum concentrations tested were 15 mmol/L of calcium and 12.5 mmol/L of phosphate. If the average particle count of three replicates exceeded USP guidelines, the solution was determined to be incompatible. This study found that 12.5 and 10 mmol/L of calcium and phosphate, respectively, are compatible in neonatal parenteral nutrition solutions compounded with 2.5% amino acids of either TrophAmine or Premasol. There did not appear to be significant differences in compatibility for solutions containing TrophAmine or Premasol when solutions were compounded with either CaCl2 or CaGlu-Pl. This study presents data in order to evaluate options for adding calcium and phosphate to neonatal parenteral nutrition solutions during shortages of calcium and cysteine.

Effect of calcium lactate in erosion and S. mutans in rats when added to Coca-Cola.

Science.gov (United States)

Beiraghi, S; Atkins, S; Rosen, S; Wilson, S; Odom, J; Beck, M

1989-12-01

Thirty-six Sprague Dawley rats, 22 days of age, were divided randomly into three groups of 12 each and housed in a programmable feeder. The three experimental groups received either Coca-Cola (CC), Coca-Cola with calcium lactate (CC-CaL), or distilled water. The programmable feeder was set to deliver 17 equal volumes of fluid per day with each feeding period lasting between 80-90 min. All groups were given Diet MIT 305 in one premeasured amount per 24 hr period (ad libitum). The pH of the CC with calcium lactate was adjusted to match the CC without calcium lactate by the addition of citric and phosphoric acids. The test period lasted five weeks. Each week, the food and fluid consumed and the weight gain were measured. Erosion of the teeth was scored by the method of Restarski et al. (1945). ANOVA indicated that there was a significant difference in the amount of erosion among groups. A Newman-Keuls analysis showed that the mean erosion score of the CC group was significantly greater (P less than 0.05) than that of the CC-CaL and distilled water groups (54.2 +/- 0.12; 0.0275 +/- 0.0123; 0.132 +/- 0.070, respectively). There was no significant difference in erosion between the CC-CaL and distilled water groups. There was no difference in the amount of food and fluid consumed among the group of rats. In conclusion, calcium lactate added to CC resulted in significantly reduced tooth erosion in rats.

49 CFR 386.54 - Administrative Law Judge.

Science.gov (United States)

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Administrative Law Judge. 386.54 Section 386.54... General Rules and Hearings § 386.54 Administrative Law Judge. (a) Powers of an Administrative Law Judge. The Administrative Law Judge may take any action and may prescribe all necessary rules and regulations...

47 CFR 54.800 - Terms and definitions.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Terms and definitions. 54.800 Section 54.800... SERVICE Interstate Access Universal Service Support Mechanism § 54.800 Terms and definitions. (a) Average... § 61.3(d) of this chapter, except that it includes exogenous changes in effect prior to the effective...

High calcium concentration in bones promotes bone metastasis in renal cell carcinomas expressing calcium-sensing receptor.

Science.gov (United States)

Joeckel, Elke; Haber, Tobias; Prawitt, Dirk; Junker, Kerstin; Hampel, Christian; Thüroff, Joachim W; Roos, Frederik C; Brenner, Walburgis

2014-02-28

The prognosis for renal cell carcinoma (RCC) is related to a high rate of metastasis, including 30% of bone metastasis. Characteristic for bone tissue is a high concentration of calcium ions. In this study, we show a promoting effect of an enhanced extracellular calcium concentration on mechanisms of bone metastasis via the calcium-sensing receptor (CaSR) and its downstream signaling molecules. Our analyses were performed using 33 (11/category) matched specimens of normal and tumor tissue and 9 (3/category) primary cells derived from RCC patients of the 3 categories: non-metastasized, metastasized into the lung and metastasized into bones during a five-year period after nephrectomy. Expression of CaSR was determined by RT-PCR, Western blot analyses and flow cytometry, respectively. Cells were treated by calcium and the CaSR inhibitor NPS 2143. Cell migration was measured in a Boyden chamber with calcium (10 μM) as chemotaxin and proliferation by BrdU incorporation. The activity of intracellular signaling mediators was quantified by a phospho-kinase array and Western blot. The expression of CaSR was highest in specimens and cells of patients with bone metastases. Calcium treatment induced an increased migration (19-fold) and proliferation (2.3-fold) exclusively in RCC cells from patients with bone metastases. The CaSR inhibitor NPS 2143 elucidated the role of CaSR on the calcium-dependent effects. After treatment with calcium, the activity of AKT, PLCγ-1, p38α and JNK was clearly enhanced and PTEN expression was almost completely abolished in bone metastasizing RCC cells. Our results indicate a promoting effect of extracellular calcium on cell migration and proliferation of bone metastasizing RCC cells via highly expressed CaSR and its downstream signaling pathways. Consequently, CaSR may be regarded as a new prognostic marker predicting RCC bone metastasis.

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.

7 CFR 58.434 - Calcium chloride.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Calcium chloride. 58.434 Section 58.434 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.434 Calcium chloride. Calcium chloride, when used, shall meet the requirements of the Food...

Seasonal Variations in Mercury's Dayside Calcium Exosphere

Science.gov (United States)

Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee W.; Vervack, Ronald J., Jr.; Cassidy, Timothy A.; Sarantos, Menelaos

2014-01-01

The Mercury Atmospheric and Surface Composition Spectrometer on the MESSENGER spacecraft has observed calcium emission in Mercury's exosphere on a near-daily basis since March 2011. During MESSENGER's primary and first extended missions (March 2011 - March 2013) the dayside calcium exosphere was measured over eight Mercury years. We have simulated these data with a Monte Carlo model of exospheric source processes to show that (a) there is a persistent source of energetic calcium located in the dawn equatorial region, (b) there is a seasonal dependence in the calcium source rate, and (c) there are no obvious year-to-year variations in the near-surface dayside calcium exosphere. Although the precise mechanism responsible for ejecting the calcium has not yet been determined, the most likely process is the dissociation of Ca-bearing molecules produced in micrometeoroid impact plumes to form energetic, escaping calcium atoms.

Altered Elementary Calcium Release Events and Enhanced Calcium Release by Thymol in Rat Skeletal Muscle

OpenAIRE

Szentesi, Péter; Szappanos, Henrietta; Szegedi, Csaba; Gönczi, Monika; Jona, István; Cseri, Julianna; Kovács, László; Csernoch, László

2004-01-01

The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine bind...

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

Science.gov (United States)

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

2017-07-01

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

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... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally recognized as...

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 generally...

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....3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally...

21 CFR 582.6195 - Calcium citrate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.6195 Section 582.6195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance is generally...

21 CFR 582.6219 - Calcium phytate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phytate. 582.6219 Section 582.6219 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium phytate. (a) Product. Calcium phytate. (b) Conditions of use. This substance is generally...

21 CFR 582.7187 - Calcium alginate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

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) Limitations...

Mechanism of store-operated calcium entry

Indian Academy of Sciences (India)

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 ...

21 CFR 582.6193 - Calcium chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.6193 Section 582.6193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This substance is generally...

Genome-wide analysis of wheat calcium ATPases and potential role of selected ACAs and ECAs in calcium stress.

Science.gov (United States)

Aslam, Roohi; Williams, Lorraine E; Bhatti, Muhammad Faraz; Virk, Nasar

2017-10-27

P 2 - type calcium ATPases (ACAs-auto inhibited calcium ATPases and ECAs-endoplasmic reticulum calcium ATPases) belong to the P- type ATPase family of active membrane transporters and are significantly involved in maintaining accurate levels of Ca 2+ , Mn 2+ and Zn 2+ in the cytosol as well as playing a very important role in stress signaling, stomatal opening and closing and pollen tube growth. Here we report the identification and possible role of some of these ATPases from wheat. In this study, ACA and ECA sequences of six species (belonging to Poaceae) were retrieved from different databases and a phylogenetic tree was constructed. A high degree of evolutionary relatedness was observed among P 2 sequences characterized in this study. Members of the respective groups from different plant species were observed to fall under the same clade. This pattern highlights the common ancestry of P 2- type calcium ATPases. Furthermore, qRT-PCR was used to analyse the expression of selected ACAs and ECAs from Triticum aestivum (wheat) under calcium toxicity and calcium deficiency. The data indicated that expression of ECAs is enhanced under calcium stress, suggesting possible roles of these ATPases in calcium homeostasis in wheat. Similarly, the expression of ACAs was significantly different in plants grown under calcium stress as compared to plants grown under control conditions. This gives clues to the role of ACAs in signal transduction during calcium stress in wheat. Here we concluded that wheat genome consists of nine P 2B and three P 2A -type calcium ATPases. Moreover, gene loss events in wheat ancestors lead to the loss of a particular homoeolog of a gene in wheat. To elaborate the role of these wheat ATPases, qRT-PCR was performed. The results indicated that when plants are exposed to calcium stress, both P 2A and P 2B gene expression get enhanced. This further gives clues about the possible role of these ATPases in wheat in calcium management. These findings can be

In vitro calcium availability in bakery products fortified with tuna bone powder as a natural calcium source.

Science.gov (United States)

Nemati, Mahnaz; Kamilah, Hanisah; Huda, Nurul; Ariffin, Fazilah

2015-08-01

Avoidance of dairy products due to lactose intolerance can lead to insufficiency of calcium (Ca) in the body. In an approach to address this problem, tuna bone powder (TBP) was formulated as a calcium supplement to fortify bakery products. In a study, TBP recovered by alkaline treatment contained 38.16 g/100 g of calcium and 23.31 g/100 g of phosphorus. The ratio of Ca:P that was close to 2:1 was hence comparable to that in human bones. The availability of calcium in TBP was 53.93%, which was significantly higher than most calcium salts, tricalcium phosphate (TCP) being the exception. In vitro availability of calcium in TBP-fortified cookies or TCP-fortified cookies were comparable at 38.9% and 39.5%, respectively. These values were higher than the readings from TBP-fortified bread (36.7%) or TCP-fortified bread (37.4%). Sensory evaluation of bakery products containing TBP or TCP elicited comparable scores for the two additives from test panels. Hence, TBP could be used in the production of high calcium bakery products that would enjoy consumer acceptance.

Medical uses of radioactive calcium. Review of an IAEA programme to promote the applications of calcium-47

International Nuclear Information System (INIS)

1963-01-01

Calcium plays a number of biologically essential roles, which have long been under investigation by various techniques available to medical science. One of the most important of these techniques is radioactive tracer analysis, i. e. study of the functions of calcium within the body with the help of a radioactive isotope of the element. The calcium-47 programme of the International Atomic Energy Agency is intended to promote these investigations by facilitating the production and use of this isotope. The importance attached to calcium- 47 is due to the special properties of this isotope, which make it the most valuable tool for many calcium studies by the radioactive tracer method. The Agency has for four years been engaged in a comprehensive effort to bring calcium- 47 into routine medical use. To this end, it has surveyed the need for this isotope, stimulated its cheaper production, encouraged the investigation of its medical possibilities, and arranged for the dissemination of the information thus obtained. The fact that calcium-47 is no longer considered an exotic isotope is at least partly due to the Agency's efforts, in co-operation with interested scientists throughout the world

42 CFR 433.54 - Bona fide donations.

Science.gov (United States)

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Bona fide donations. 433.54 Section 433.54 Public... Financial Participation § 433.54 Bona fide donations. (a) A bona fide donation means a provider-related donation, as defined in § 433.52, made to the State or unit of local government, that has no direct or...

7 CFR 54.1001 - Meaning of words.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Meaning of words. 54.1001 Section 54.1001 Agriculture... and Poultry Products § 54.1001 Meaning of words. For the purposes of the regulations in this subpart, words in the singular form shall be deemed to impart the plural and vice versa, as the case may demand. ...

A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration.

Science.gov (United States)

Zhang, Qinghao; Schmelzer, Eva; Gerlach, Jörg C; Nettleship, Ian

2017-04-01

Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH) 2 and CaCO 3 . The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of exhausting exercise and calcium supplementation on potassium, magnesium, copper, zinc and calcium levels in athletes

International Nuclear Information System (INIS)

Cinar, V.; Baltaci, A.K.; Mogulkoc, R.

2009-01-01

Present study was performed to determine four week calcium supplementation and athleticism exercise on plasma potassium, calcium, magnesium, cupper and zinc levels in resting and exhaustion. Research was carried out on 30 healthy male people. Group 1; Exercise, Group 2; Exercise + Calcium supplementation, Group 3; Sedentary + Calcium supplemented. All elements levels increased by exhausting exercise (P<0.05). Plasma K and Ca levels increased in exercise group after supplementation (P<0.05). Ca levels increased in exercise + supplemented group (P<0.05). This increase was much more in group three (P<0.05). Plasma Cu levels increased by Ca supplementation in sedentary (P<0.05). Exhausting exercise increased Zn levels in sedentary after supplementation (P<0.05). The results of present study show that calcium supplementation for 4 week does not have clear affect on potassium and Mg. However, calcium levels were increased by supplementation and Cu after the supplementation. It was also exhausting exercise that caused increase in all parameters. (author)

Inhibition of metastin (kisspeptin-54)-GPR54 signaling in the arcuate nucleus-median eminence region during lactation in rats.

Science.gov (United States)

Yamada, S; Uenoyama, Y; Kinoshita, M; Iwata, K; Takase, K; Matsui, H; Adachi, S; Inoue, K; Maeda, K-I; Tsukamura, H

2007-05-01

Follicular development and ovulation are suppressed during lactation in various mammalian species, mainly due to the suppression of pulsatile GnRH/LH secretion. Metastin (kisspeptin-54), a KiSS-1 gene product, is an endogenous ligand for GPR54, a G-protein-coupled receptor, and suggested to play a critical role in regulating the gonadal axis. The present study therefore aims to determine whether metastin (kisspeptin-54)-GPR54 signaling in discrete brain areas is inhibited by the suckling stimulus that causes suppression of LH secretion in lactating rats. Quantitative RT-PCR revealed that the KiSS-1 mRNA level was significantly lower in the arcuate nucleus (ARC)-median eminence region in lactating ovariectomized (OVX) and estrogen-treated OVX rats than in nonlactating controls. KiSS-1 mRNA in the anteroventral periventricular nucleus was kept at a low level in both lactating and nonlactating rats despite estrogen treatment. GPR54 mRNA levels were significantly lower in lactating than nonlactating rats in the anteroventral periventricular nucleus, but the levels in lactating mothers of the preoptic area and ARC-median eminence were comparable with nonlactating controls. Although KiSS-1 mRNA-expressing cells or metastin (kisspeptin-54) immunoreactivities were densely located in the ARC of nonlactating controls, few were found in the ARC of lactating OVX animals. Various doses of metastin (kisspeptin-54) (0.02, 0.2, and 2 nmol) injected into the third ventricle caused a significant increase in LH secretion in both lactating and nonlactating OVX rats, suggesting that lactating rats are responsive to metastin (kisspeptin-54) stimulus. Thus, the present study demonstrated that KiSS-1 mRNA/metastin (kisspeptin-54) expression is inhibited in the ARC by the suckling stimulus, suggesting that the inhibition is most probably involved in suppressing LH secretion in lactating rats.

21 CFR 582.5230 - Calcium sulfate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sulfate. 582.5230 Section 582.5230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This substance...

21 CFR 582.5195 - Calcium citrate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.5195 Section 582.5195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance...

21 CFR 582.1207 - Calcium lactate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium lactate. 582.1207 Section 582.1207 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1207 Calcium lactate. (a) Product. Calcium lactate. (b) Conditions of use. This substance is...

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... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c) Limitations...

21 CFR 582.1195 - Calcium citrate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.1195 Section 582.1195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance is...

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 generally...

21 CFR 582.1193 - Calcium chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.1193 Section 582.1193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1193 Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This substance...

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

Directory of Open Access Journals (Sweden)

Xixi Cai

2016-12-01

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

How calcium makes endocytic receptors attractive

DEFF Research Database (Denmark)

Andersen, Christian B F; Moestrup, Søren K

2014-01-01

of the receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect...... the receptor calcium sites....

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

Transgenic plants with increased calcium stores

Science.gov (United States)

Wyatt, Sarah (Inventor); Tsou, Pei-Lan (Inventor); Robertson, Dominique (Inventor); Boss, Wendy (Inventor)

2004-01-01

The present invention provides transgenic plants over-expressing a transgene encoding a calcium-binding protein or peptide (CaBP). Preferably, the CaBP is a calcium storage protein and over-expression thereof does not have undue adverse effects on calcium homeostasis or biochemical pathways that are regulated by calcium. In preferred embodiments, the CaBP is calreticulin (CRT) or calsequestrin. In more preferred embodiments, the CaBP is the C-domain of CRT, a fragment of the C-domain, or multimers of the foregoing. In other preferred embodiments, the CaBP is localized to the endoplasmic reticulum by operatively associating the transgene encoding the CaBP with an endoplasmic reticulum localization peptide. Alternatively, the CaBP is targeted to any other sub-cellular compartment that permits the calcium to be stored in a form that is biologically available to the plant. Also provided are methods of producing plants with desirable phenotypic traits by transformation of the plant with a transgene encoding a CaBP. Such phenotypic traits include increased calcium storage, enhanced resistance to calcium-limiting conditions, enhanced growth and viability, increased disease and stress resistance, enhanced flower and fruit production, reduced senescence, and a decreased need for fertilizer production. Further provided are plants with enhanced nutritional value as human food or animal feed.

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 is...

Calcium Orthophosphate Cements and Concretes

Directory of Open Access Journals (Sweden)

Sergey V. Dorozhkin

2009-03-01

Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

Discrete-State Stochastic Models of Calcium-Regulated Calcium Influx and Subspace Dynamics Are Not Well-Approximated by ODEs That Neglect Concentration Fluctuations

Science.gov (United States)

Weinberg, Seth H.; Smith, Gregory D.

2012-01-01

Cardiac myocyte calcium signaling is often modeled using deterministic ordinary differential equations (ODEs) and mass-action kinetics. However, spatially restricted “domains” associated with calcium influx are small enough (e.g., 10−17 liters) that local signaling may involve 1–100 calcium ions. Is it appropriate to model the dynamics of subspace calcium using deterministic ODEs or, alternatively, do we require stochastic descriptions that account for the fundamentally discrete nature of these local calcium signals? To address this question, we constructed a minimal Markov model of a calcium-regulated calcium channel and associated subspace. We compared the expected value of fluctuating subspace calcium concentration (a result that accounts for the small subspace volume) with the corresponding deterministic model (an approximation that assumes large system size). When subspace calcium did not regulate calcium influx, the deterministic and stochastic descriptions agreed. However, when calcium binding altered channel activity in the model, the continuous deterministic description often deviated significantly from the discrete stochastic model, unless the subspace volume is unrealistically large and/or the kinetics of the calcium binding are sufficiently fast. This principle was also demonstrated using a physiologically realistic model of calmodulin regulation of L-type calcium channels introduced by Yue and coworkers. PMID:23509597

Voltage-gated calcium flux mediates Escherichia coli mechanosensation.

Science.gov (United States)

Bruni, Giancarlo N; Weekley, R Andrew; Dodd, Benjamin J T; Kralj, Joel M

2017-08-29

Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tools. Only recently were bacteria shown to modulate their membrane potential on the timescale of seconds, and little is known about the downstream effects from this modulation. In this paper, we report on the effects of electrophysiology in individual bacteria. A genetically encoded calcium sensor expressed in Escherichia coli revealed calcium transients in single cells. A fusion sensor that simultaneously reports voltage and calcium indicated that calcium influx is induced by voltage depolarizations, similar to metazoan action potentials. Cytoplasmic calcium levels and transients increased upon mechanical stimulation with a hydrogel, and single cells altered protein concentrations dependent on the mechanical environment. Blocking voltage and calcium flux altered mechanically induced changes in protein concentration, while inducing calcium flux reproduced these changes. Thus, voltage and calcium relay a bacterial sense of touch and alter cellular lifestyle. Although the calcium effectors remain unknown, these data open a host of new questions about E. coli , including the identity of the underlying molecular players, as well as other signals conveyed by voltage and calcium. These data also provide evidence that dynamic voltage and calcium exists as a signaling modality in the oldest domain of life, and therefore studying electrophysiology beyond canonical electrically excitable cells could yield exciting new findings.

Diffusion of calcium in pure and doped NaCl; Diffusion du calcium dans NaCl pur et dope

Energy Technology Data Exchange (ETDEWEB)

Slifkin, L; Brebec, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

We have determined, by diffusion experiments of Ca in pure and doped NaCl, the activation energy for the calcium jumps and the binding energy between calcium ion and vacancy. (authors) [French] Nous avons determine, par des mesures de diffusion du Ca dans NaCl pur et NaCl dope avec CaCl{sub 2}, l'energie d'activation relative aux sauts du calcium et l'energie de liaison lacune-calcium. (auteurs)

21 CFR 201.70 - Calcium labeling.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Calcium labeling. 201.70 Section 201.70 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.70 Calcium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the calcium content per...

Calcium supplementation in osteoporosis: useful or harmful?

Science.gov (United States)

Chiodini, Iacopo; Bolland, Mark J

2018-04-01

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

A sensor for calcium uptake

Science.gov (United States)

Collins, Sean; Meyer, Tobias

2011-01-01

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. PMID:20844529

Children's Bone Health and Calcium

Science.gov (United States)

... Twitter Pinterest Email Print Children's Bone Health and Calcium: Condition Information What is bone health and how ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

Role of polyhydroxybutyrate in mitochondrial calcium uptake

Science.gov (United States)

Smithen, Matthew; Elustondo, Pia A.; Winkfein, Robert; Zakharian, Eleonora; Abramov, Andrey Y.; Pavlov, Evgeny

2013-01-01

Polyhydroxybutyrate (PHB) is a biological polymer which belongs to the class of polyesters and is ubiquitously present in all living organisms. Mammalian mitochondrial membranes contain PHB consisting of up to 120 hydroxybutyrate residues. Roles played by PHB in mammalian mitochondria remain obscure. It was previously demonstrated that PHB of the size similar to one found in mitochondria mediates calcium transport in lipid bilayer membranes. We hypothesized that the presence of PHB in mitochondrial membrane might play a significant role in mitochondrial calcium transport. To test this, we investigated how the induction of PHB hydrolysis affects mitochondrial calcium transport. Mitochondrial PHB was altered enzymatically by targeted expression of bacterial PHB hydrolyzing enzyme (PhaZ7) in mitochondria of mammalian cultured cells. The expression of PhaZ7 induced changes in mitochondrial metabolism resulting in decreased mitochondrial membrane potential in HepG2 but not in U87 and HeLa cells. Furthermore, it significantly inhibited mitochondrial calcium uptake in intact HepG2, U87 and HeLa cells stimulated by the ATP or by the application of increased concentrations of calcium to the digitonin permeabilized cells. Calcium uptake in PhaZ7 expressing cells was restored by mimicking calcium uniporter properties with natural electrogenic calcium ionophore - ferutinin. We propose that PHB is a previously unrecognized important component of the mitochondrial calcium uptake system. PMID:23702223

Trace mineral interactions during elevated calcium consumption

International Nuclear Information System (INIS)

Smith, K.T.; Luhrsen, K.R.

1986-01-01

Elevated calcium consumption is reported to affect trace mineral bioavailability. The authors examined this phenomenon in both single dose radio-label test meals and an eight week feeding trial in rats. In the single dose studies, human milk, cows milk, and various calcium sources were examined in relation to radio-iron and radio-zinc retention. 59 Fe retention was greater from human milk than cows milk. However, when the calcium content of human milk was adjusted (with CaHPO 4 or CaCO 3 ) to equal the level in cows milk, iron retention was depressed. Similarly, when calcium sources (CaCO 3 , CaHPO 4 , hydroxy-apatite, bone meal) were examined at different calcium:metal molar ratios, the degree of inhibition on metal retention varied. In general, phosphate salts were more inhibiting than carbonates. In the feeding trial, calcium was fed in diets at normal (0.5%) or elevated (1.5%) levels. Serum, liver, kidney, and bone trace mineral profiles were obtained. In general, most trace elements showed decreased levels in the tissues. Zinc and iron were most striking, followed by magnesium with minor changes in copper. A high calcium:high mineral supplemented group was also fed. Mixed mineral supplementation prevented all calcium interactions. These data indicate the importance of calcium mineral interactions in bioavailability considerations in both milk sources and in mineral supplementation

Oxalic acid decreases calcium absorption in rats

International Nuclear Information System (INIS)

Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

1987-01-01

Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

Preparation and properties of calcium zirconate

International Nuclear Information System (INIS)

Dudek, M.; Bucko, M.; Rog, G.

2001-01-01

Dense samples of calcium zirconate were prepared. Electrical conductivity of the samples were measured in the temperature range 873 - 1273 K by both the d.c. four probe and the impedance spectroscopy methods. Calcium zirconate with small excess of calcium oxide appeared to be oxygen ion conductor. It was applied as an electrolyte in solid-state galvanic cells. (author)

Signal Recognition Particle 54 kD Protein (SRP54 from the Marine Sponge Geodia cydonium

Directory of Open Access Journals (Sweden)

Sonja Durajlija-Žinić

2002-01-01

Full Text Available In the systematic search for phylogenetically conserved proteins in the simplest and most ancient extant metazoan phylum – Porifera, we have identified and analyzed a cDNA encoding the signal recognition particle 54 kD protein (SRP54 from the marine sponge Geodia cydonium (Demospongiae. The signal recognition particle (SRP is a universally conserved ribonucleoprotein complex of a very ancient origin, comprising SRP RNA and several proteins (six in mammals. The nucleotide sequence of the sponge cDNA predicts a protein of 499 amino acid residues with a calculated Mr of 55175. G. cydonium SRP54 displays unusually high overall similarity (90 % with human/mammalian SRP54 proteins, higher than with Drosophila melanogaster (88 %, or Caenorhabditis elegans (82 %. The same was found for the majority of known and phylogenetically conserved proteins from sponges, indicating that the molecular evolutionary rates in protein coding genes in Porifera as well as in highly developed mammals (vertebrates are slower, when compared with the rates in homologous genes from invertebrates (insects, nematodes. Therefore, genes/proteins from sponges might be the best candidates for the reconstruction of ancient structures of proteins and genome/proteome complexity in the ancestral organism, common to all multicellular animals.

Calcium Supplements: Do Men Need Them Too?

Science.gov (United States)

... Lifestyle Nutrition and healthy eating Should men take calcium supplements? Answers from Katherine Zeratsky, R.D., L. ... Most healthy men don't need to take calcium supplements. Calcium is important for men for optimal ...

The effect of brushing with nano calcium carbonate and calcium carbonate toothpaste on the surface roughness of nano-ionomer

Science.gov (United States)

Anisja, D. H.; Indrani, D. J.; Herda, E.

2017-08-01

Nanotechnology developments in dentistry have resulted in the development of nano-ionomer, a new restorative material. The surface roughness of restorative materials can increase bacteria adhesion and lead to poor oral hygiene. Abrasive agents in toothpaste can alter tooth and restorative material surfaces. The aim of this study is to identify the effect of brushing with nano calcium carbonate, and calcium carbonate toothpaste on surface roughness of nano-ionomer. Eighteen nano-ionomer specimens were brushed with Aquabidest (doubledistilled water), nano calcium carbonate and calcium carbonate toothpaste. Brushing lasted 30 minutes, and the roughness value (Ra) was measured after each 10 minute segment using a surface roughness tester. The data was analyzed using repeated ANOVA and one-way ANOVA test. The value of nano-ionomer surface roughness increased significantly (p<0.05) after 20 minutes of brushing with the nano calcium carbonate toothpaste. Brushing with calcium carbonate toothpaste leaves nano-ionomer surfaces more rugged than brushing with nano calcium carbonate toothpaste.

Regulation of cardiomyocyte autophagy by calcium.

Science.gov (United States)

Shaikh, Soni; Troncoso, Rodrigo; Criollo, Alfredo; Bravo-Sagua, Roberto; García, Lorena; Morselli, Eugenia; Cifuentes, Mariana; Quest, Andrew F G; Hill, Joseph A; Lavandero, Sergio

2016-04-15

Calcium signaling plays a crucial role in a multitude of events within the cardiomyocyte, including cell cycle control, growth, apoptosis, and autophagy. With respect to calcium-dependent regulation of autophagy, ion channels and exchangers, receptors, and intracellular mediators play fundamental roles. In this review, we discuss calcium-dependent regulation of cardiomyocyte autophagy, a lysosomal mechanism that is often cytoprotective, serving to defend against disease-related stress and nutrient insufficiency. We also highlight the importance of the subcellular distribution of calcium and related proteins, interorganelle communication, and other key signaling events that govern cardiomyocyte autophagy. Copyright © 2016 the American Physiological Society.

Diuretics and disorders of calcium homeostasis.

Science.gov (United States)

Grieff, Marvin; Bushinsky, David A

2011-11-01

Diuretics commonly are administered in disorders of sodium balance. Loop diuretics inhibit the Na-K-2Cl transporter and also increase calcium excretion. They are often used in the treatment of hypercalcemia. Thiazide diuretics block the thiazide-sensitive NaCl transporter in the distal convoluted tubule, and can decrease calcium excretion. They are often used in the treatment of nephrolithiasis. Carbonic anhydrase inhibitors decrease bicarbonate absorption and the resultant metabolic acidosis can increase calcium excretion. Their use can promote nephrocalcinosis and nephrolithiasis. This review will address the use of diuretics on disorders of calcium homeostasis. Copyright © 2011 Elsevier Inc. All rights reserved.

38 CFR 3.54 - Marriage dates.

Science.gov (United States)

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Marriage dates. 3.54..., Compensation, and Dependency and Indemnity Compensation Relationship § 3.54 Marriage dates. A surviving spouse may qualify for pension, compensation, or dependency and indemnity compensation if the marriage to the...

Chapter 15. Measurement of the main calcium metabolism processes

International Nuclear Information System (INIS)

Milhaud, G.

1975-01-01

A method of measuring the chief calcium metabolism processes in man is described and is based on the following techniques and theory: intraveinous injection of 45 Ca; determination of the specific radioactivity of serum calcium, total radioactivity of urine and stools, ingested and excreted calcium; mathematical analysis of the specific radioactivity decay curve for serum calcium. The following data were obtained in this way: intestinal absorption fraction of calcium in the chemical state in which it is found in foods; quantity of calcium excreted by the intestin, as distinct from the non-absorbed fraction; physiological turnover rates in the skeleton by osteolysis and osteoblastosis; mass of rapidly exchangeable calcium in the organism, i.e. the calcium pool; rates of exchange with serum calcium of calcium from the different pool components, mass of bone calcium subjected to recrystallisation. Some applications of the method in man and the verification of the theory in rats are reported [fr

Calcium phosphates: what is the evidence?

Science.gov (United States)

Larsson, Sune

2010-03-01

A number of different calcium phosphate compounds such as calcium phosphate cements and solid beta-tricalcium phosphate products have been introduced during the last decade. The chemical composition mimics the mineral phase of bone and as a result of this likeness, the materials seem to be remodeled as for normal bone through a cell-mediated process that involves osteoclastic activity. This is a major difference when compared with, for instance, calcium sulphate compounds that after implantation dissolve irrespective of the new bone formation rate. Calcium phosphates are highly biocompatible and in addition, they act as synthetic osteoconductive scaffolds after implantation in bone. When placed adjacent to bone, osteoid is formed directly on the surface of the calcium phosphate with no soft tissue interposed. Remodeling is slow and incomplete, but by adding more and larger pores, like in ultraporous beta-tricalcium phosphate, complete or nearly complete resorption can be achieved. The indications explored so far include filling of metaphyseal fracture voids or bone cysts, a volume expander in conjunction with inductive products, and as a carrier for various growth factors and antibiotics. Calcium phosphate compounds such as calcium phosphate cement and beta-tricalcium phosphate will most certainly be part of the future armamentarium when dealing with fracture treatment. It is reasonable to believe that we have so far only seen the beginning when it comes to clinical applications.

Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation

NARCIS (Netherlands)

Afdhal, N. H.; Ostrow, J. D.; Koehler, R.; Niu, N.; Groen, A. K.; Veis, A.; Nunes, D. P.; Offner, G. D.

1995-01-01

Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4

The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

International Nuclear Information System (INIS)

Vatolin, N.A.; Volkova, P.I.; Sapozhnikova, T.V.; Ovchinnikova, L.A.

1988-01-01

The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

Glass-water interphase reactivity with calcium rich solutions

International Nuclear Information System (INIS)

Chave, T.; Frugier, P.; Gin, S.; Chave, T.; Ayral, A.

2011-01-01

The effect of calcium on synthetic glass alteration mechanisms has been studied. It is known that the higher the calcium content in the glass, the higher the forward rate. However, in a confined medium reaching apparent saturation state and a pH (90 degrees C) around 9, synthetic calcium-bearing glasses are those with the lowest alteration rates. This work brings new and fundamental evidence toward understanding the alteration mechanisms: the rate-decreasing effect of calcium exists even if the calcium comes from the solution. Calcium from solution reacts with silica network in the hydrated layer at the glass surface. The calcium effect on the alteration kinetics is explained by the condensation of a passivating reactive interphase (PRI) whose passivating properties are strongly enhanced when calcium participates in its construction. These experiments provide new evidence of the role of condensation mechanisms in glass alteration. This better understanding of the calcium effect on glass long-term behavior will be useful both for improving glass formulations and for understanding the influence of the water composition. (authors)

Calcium – how and why?

Indian Academy of Sciences (India)

Unknown

biological processes because of its unusual physical and chemical properties. 1. History of calcium ... cellular roles of calcium has established the importance of this ion ..... Ca2+ ion, for example in regulating enzyme activity (Price. 1975 ...

Effect of calcium chloride and calcium lactate on quality and shelf-life of fresh-cut guava slices

International Nuclear Information System (INIS)

Raheem, M.I.U.; Huma, N.; Anjum, F.M.

2013-01-01

Present study was conducted to investigate the effectiveness of chemical treatments at low temperature on the quality of fresh-cut guava slices during 2011-12. Uniform sized guava slices were made free from seeds and treated with calcium chloride and calcium lactate with concentration 0.9%, 1.8%, 2.7% or 3.6%. After packing in plastic boxes, all treated samples were stored at 5 degree C + 2 degree C in a refrigerator for 24 days with 6 day interval between different removals. The results obtained from physico-chemical analysis showed decrease in firmness (111.67-12.67gf) and increase in browning (1.19-1.93nm) of guava slices compared to control with the passage of storage interval. Moreover, scores in taste (7.33-1.00), flavour (7.33-1.00), colour (7.50-1.00) and texture (7.67-1.00) of guava slices was also decreased with respect to interaction of treatments and storage period. Calcium chloride at the rate 2.7% showed significantly higher stability than other concentrations of calcium chloride and calcium lactate in delaying firmness and browning of fresh-cut guava slices along with maintaining their organoleptic properties for longer storage period. However, calcium chloride imparted undesirable bitterness to fresh-cut guava slices at the concentration of 3.6%. Based on the overall quality performance, 2.7% calcium chloride and 3.6% calcium lactate exhibited better results than other concentrations and control with storage life of 8 days at 5 degree C + 2 degree C. (author)

Bcl-2 overexpression: effects on transmembrane calcium movement

International Nuclear Information System (INIS)

Rangaswami, Arun A.; Premack, Brett; Walleczek, Jan; Killoran, Pamela; Gardner, Phyllis; Knox, Susan J.

1996-01-01

Purpose/Objective: High levels of expression of the proto-oncogene bcl-2 and its 26 kD protein product Bcl-2 have been correlated with the inhibition of apoptosis and the increased resistance of tumor cells to cytotoxic drugs and ionizing radiation. Unfortunately, the specific mechanism of action of Bcl-2 remains poorly understood. In the studies described here, the role of intracellular calcium fluxes and plasma membrane calcium cycling in the induction of apoptosis, and the effect of Bcl-2 expression on the modulation of transmembrane calcium fluxes following treatment of cells with cytotoxic agents were studied. The relationship between intracellular calcium release, capacitive calcium entry, and the plasma membrane potential were also investigated. Materials and Methods: Human B-cell lymphoma (PW) and human promyelocytic leukemia (HL60) cell lines were transfected with Bcl-2 and a control vector. The Bcl-2 transfectants over expressed the Bcl-2 onco-protein and were more resistant to irradiation than the control cells. Cells were loaded with fluorescent indicators indo-1 and fura-2 AM to quantify the cytosolic calcium concentration and subsequent calcium responses to a variety of cytotoxic stimuli, including the microsomal ATPase inhibitor, thapsigargin, using fluorometric measurements. Comparisons of resting and stimulated cytosolic calcium concentrations were made between the parental, neomycin control, and bcl-2 transfected cells. In order to determine the actual calcium influx rate, cells were loaded with either indo-1 or fura-2 and then exposed to 0.1 mM extracellular manganese, which enters the cells through calcium influx channels and quenches the fluorescent signal in proportion to the calcium influx rate. In order to determine the role of the membrane potential in driving calcium influx, cells were treated with either 0.1 μM Valinomycin or isotonic potassium chloride to either hyper polarize or depolarize the resting membrane potential, and the

21 CFR 184.1206 - Calcium iodate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium iodate. 184.1206 Section 184.1206 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1206 Calcium iodate. (a) Calcium iodate [Ca(IO3)2·H2O, CAS Reg. No. 7789-80...

The total synthesis of calcium atorvastatin.

Science.gov (United States)

Dias, Luiz C; Vieira, Adriano S; Barreiro, Eliezer J

2016-02-21

A practical and convergent asymmetric route to calcium atorvastatin (1) is reported. The synthesis of calcium atorvastatin (1) was performed using the remote 1,5-anti asymmetric induction in the boron-mediated aldol reaction of β-alkoxy methylketone (4) with pyrrolic aldehyde (3) as a key step. Calcium atorvastatin was obtained from aldehyde (3) after 6 steps, with a 41% overall yield.

Calcium dynamics in vascular smooth muscle

OpenAIRE

Amberg, Gregory C.; Navedo, Manuel F.

2013-01-01

Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves

OpenAIRE

Tuan, Hoang-Trong Minh; Williams, George S. B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet

2011-01-01

A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

Immobilization of calcium sulfate contained in demolition waste

International Nuclear Information System (INIS)

Ambroise, J.; Pera, J.

2008-01-01

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

Calcium intake and risk of fracture: systematic review.

Science.gov (United States)

Bolland, Mark J; Leung, William; Tai, Vicky; Bastin, Sonja; Gamble, Greg D; Grey, Andrew; Reid, Ian R

2015-09-29

To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures. Systematic review of randomised controlled trials and observational studies of calcium intake with fracture as an endpoint. Results from trials were pooled with random effects meta-analyses. Ovid Medline, Embase, PubMed, and references from relevant systematic reviews. Initial searches undertaken in July 2013 and updated in September 2014. Randomised controlled trials or cohort studies of dietary calcium, milk or dairy intake, or calcium supplements (with or without vitamin D) with fracture as an outcome and participants aged >50. There were only two eligible randomised controlled trials of dietary sources of calcium (n=262), but 50 reports from 44 cohort studies of relations between dietary calcium (n=37), milk (n=14), or dairy intake (n=8) and fracture outcomes. For dietary calcium, most studies reported no association between calcium intake and fracture (14/22 for total, 17/21 for hip, 7/8 for vertebral, and 5/7 for forearm fracture). For milk (25/28) and dairy intake (11/13), most studies also reported no associations. In 26 randomised controlled trials, calcium supplements reduced the risk of total fracture (20 studies, n=58,573; relative risk 0.89, 95% confidence interval 0.81 to 0.96) and vertebral fracture (12 studies, n=48,967. 0.86, 0.74 to 1.00) but not hip (13 studies, n=56,648; 0.95, 0.76 to 1.18) or forearm fracture (eight studies, n=51,775; 0.96, 0.85 to 1.09). Funnel plot inspection and Egger's regression suggested bias toward calcium supplements in the published data. In randomised controlled trials at lowest risk of bias (four studies, n=44,505), there was no effect on risk of fracture at any site. Results were similar for trials of calcium monotherapy and co-administered calcium and vitamin D. Only one trial in frail elderly women in residential care with low dietary calcium intake and vitamin D

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.

L-Type Calcium Channels Modulation by Estradiol.

Science.gov (United States)

Vega-Vela, Nelson E; Osorio, Daniel; Avila-Rodriguez, Marco; Gonzalez, Janneth; García-Segura, Luis Miguel; Echeverria, Valentina; Barreto, George E

2017-09-01

Voltage-gated calcium channels are key regulators of brain function, and their dysfunction has been associated with multiple conditions and neurodegenerative diseases because they couple membrane depolarization to the influx of calcium-and other processes such as gene expression-in excitable cells. L-type calcium channels, one of the three major classes and probably the best characterized of the voltage-gated calcium channels, act as an essential calcium binding proteins with a significant biological relevance. It is well known that estradiol can activate rapidly brain signaling pathways and modulatory/regulatory proteins through non-genomic (or non-transcriptional) mechanisms, which lead to an increase of intracellular calcium that activate multiple kinases and signaling cascades, in the same way as L-type calcium channels responses. In this context, estrogens-L-type calcium channels signaling raises intracellular calcium levels and activates the same signaling cascades in the brain probably through estrogen receptor-independent modulatory mechanisms. In this review, we discuss the available literature on this area, which seems to suggest that estradiol exerts dual effects/modulation on these channels in a concentration-dependent manner (as a potentiator of these channels in pM concentrations and as an inhibitor in nM concentrations). Indeed, estradiol may orchestrate multiple neurotrophic responses, which open a new avenue for the development of novel estrogen-based therapies to alleviate different neuropathologies. We also highlight that it is essential to determine through computational and/or experimental approaches the interaction between estradiol and L-type calcium channels to assist these developments, which is an interesting area of research that deserves a closer look in future biomedical research.

Parents' Calcium Knowledge Is Associated with Parental Practices to Promote Calcium Intake among Parents of Early Adolescent Children

Science.gov (United States)

Gunther, Carolyn W.; Rose, Angela M.; Bruhn, Christine; Cluskey, Mary; Reicks, Marla; Richards, Rickelle; Wong, Siew Sun; Boushey, Carol J.; Misner, Scottie; Olson, Beth

2015-01-01

The study reported here aimed to identify the relationship of parents' calcium knowledge with diet-related parental practices and determinants of calcium knowledge. A cross-sectional survey was conducted measuring parental practices, calcium knowledge, and demographics. A convenience sample of 599 racially/ethnically diverse parents of children…

Depletion of intracellular calcium stores facilitates the influx of extracellular calcium in platelet derived growth factor stimulated A172 glioblastoma cells.

Science.gov (United States)

Vereb, G; Szöllösi, J; Mátyus, L; Balázs, M; Hyun, W C; Feuerstein, B G

1996-05-01

Calcium signaling in non-excitable cells is the consequence of calcium release from intracellular stores, at times followed by entry of extracellular calcium through the plasma membrane. To study whether entry of calcium depends upon the level of saturation of intracellular stores, we measured calcium channel opening in the plasma membrane of single confluent A172 glioblastoma cells stimulated with platelet derived growth factor (PDGF) and/or bradykinin (BK). We monitored the entry of extracellular calcium by measuring manganese quenching of Indo-1 fluorescence. PDGF raised intracellular calcium concentration ([Ca2+]i) after a dose-dependent delay (tdel) and then opened calcium channels after a dose-independent delay (tch). At higher doses (> 3 nM), BK increased [Ca2+]i after a tdel approximately 0 s, and tch decreased inversely with both dose and peak [Ca2+]i. Experiments with thapsigargin (TG), BK, and PDGF indicated that BK and PDGF share intracellular Ca2+ pools that are sensitive to TG. When these stores were depleted by treatment with BK and intracellular BAPTA, tdel did not change, but tch fell to almost 0 s in PDGF stimulated cells, indicating that depletion of calcium stores affects calcium channel opening in the plasma membrane. Our data support the capacitative model for calcium channel opening and the steady-state model describing quantal Ca2+ release from intracellular stores.

Calcium supplementation and cardiovascular risk: A rising concern.

Science.gov (United States)

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

2017-06-01

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

Calcium signals in olfactory neurons.

Science.gov (United States)

Tareilus, E; Noé, J; Breer, H

1995-11-09

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.

The increasing of enamel calcium level after casein phosphopeptideamorphous calcium phosphate covering

OpenAIRE

Widyasri Prananingrum; Puguh Bayu Prabowo

2012-01-01

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 an...

Modulation of intestinal absorption of calcium

Energy Technology Data Exchange (ETDEWEB)

Fournier, P; Dupuis, Y [Ecole Pratique des Hautes Etudes, 75 - Paris (France); Paris-11 Univ., 92 - Chatenay-Malabry (France))

1975-01-01

Absorption of ingested calcium (2ml of a 10mM CaCl/sub 2/ solution + /sup 45/Ca) by the adult rat was shown to be facilitated by the simultaneous ingestion of an active carbohydrate, L-arabinose. As the carbohydrate concentration is increased from 10 to 200mM, the absorption of calcium is maximised at a level corresponding to about twice the control absorption level. A similar doubling of calcium absorption is obtained when a 100mM concentration of any one of a number of other carbohydrates is ingested simultaneously with a 10mM CaCl/sub 2/ solution. Conversely, the simultaneous ingestion of increasing doses (10 to 100mM) of phosphate (NaH/sub 2/PO/sub 4/) with a 10mM CaCl/sub 2/ solution results in decreased /sup 45/Ca absorption and retention by the adult rat. The maximum inhibition of calcium absorption by phosphate is independent of the concentration of the ingested calcium solution (from 5 to 50mM CaCl/sub 2/). The simultaneous ingestion of CaCl/sub 2/ (10mM) with lactose and sodium phosphate (50 and 10mM respectively) shows that the activation effect of lactose upon /sup 45/Ca absorption may be partly dissimulated by the presence of phosphate. These various observations indicate that, within a large concentration range (2 to 50mM CaCl/sub 2/) calcium absorption appears to be a precisely modulated diffusion process. Calcium absorption varies (between minimum and maximum levels) as a function of the state of saturation by the activators (carbohydrates) and inhibitors (phosphate) of the calcium transport system.

Intracellular free calcium concentration and calcium transport in human erythrocytes of lead-exposed workers

International Nuclear Information System (INIS)

Quintanar-Escorza, M.A.; Gonzalez-Martinez, M.T.; Navarro, L.; Maldonado, M.; Arevalo, B.; Calderon-Salinas, J.V.

2007-01-01

Erythrocytes are the route of lead distribution to organs and tissues. The effect of lead on calcium homeostasis in human erythrocytes and other excitable cells is not known. In the present work we studied the effect of lead intoxication on the uptake and efflux (measured as (Ca 2+ -Mg 2+ )-ATPase activity) of calcium were studied in erythrocytes obtained from lead-exposed workers. Blood samples were taken from 15 workers exposed to lead (blood lead concentration 74.4 ± 21.9 μg/dl) and 15 non-exposed workers (9.9 ± 2 μg/dl). In erythrocytes of lead-exposed workers, the intracellular free calcium was 79 ± 13 nM, a significantly higher concentration (ANOVA, P 2+ -Mg 2+ )-ATPase activity. Lipid peroxidation was 1.7-fold higher in erythrocytes of lead-exposed workers as compared with control. The alteration on calcium equilibrium in erythrocytes is discussed in light of the toxicological effects in lead-exposed workers

Solubility of calcium in CaO-CaCl2

International Nuclear Information System (INIS)

Perry, G.S.; Shaw, S.J.

1991-06-01

The Direct Oxide Reduction (DOR) process is well established as a process to produce plutonium metal from plutonium dioxide by reaction with calcium. Calcium chloride is added to dissolve the calcium oxide produced, allowing the metal to coalesce into a button. Since calcium metal melts at 840 0 C and DOR can take place successfully below this temperature, it is likely calcium dissolved in calcium chloride reacts with the plutonium dioxide. The solubility of calcium in calcium chloride is reasonably well established but the effect of the CaO formed during the DOR process on the solubility of calcium has not been previously determined. For this reason the solubility of calcium in CaCl 2 -CaO melts at 800 o C has been studied. The solubility decreases from 2.7 mol % in CaCl 2 to 0.4 mol % in 9 mol % CaO-CaCl 2 . (author)

Hydrocarbon-soluble calcium hydride: a "worker-bee" in calcium chemistry.

Science.gov (United States)

Spielmann, Jan; Harder, Sjoerd

2007-01-01

The reactivity of the hydrocarbon-soluble calcium hydride complex [{CaH(dipp-nacnac)(thf)}(2)] (1; dipp-nacnac=CH{(CMe)(2,6-iPr(2)C(6)H(3)N)}(2)) with a large variety of substrates has been investigated. Addition of 1 to C=O and C=N functionalities gave easy access to calcium alkoxide and amide complexes. Similarly, reduction of the C[triple chemical bond]N bond in a cyanide or an isocyanide resulted in the first calcium aldimide complexes [Ca{N=C(H)R}(dipp-nacnac)] and [Ca{C(H)=NR}(dipp-nacnac)], respectively. Complexation of 1 with borane or alane Lewis acids gave the borates and alanates as contact ion pairs. In reaction with epoxides, nucleophilic ring-opening is observed as the major reaction. The high reactivity of hydrocarbon-soluble 1 with most functional groups contrasts strongly with that of insoluble CaH(2), which is essentially inert and is used as a common drying agent. Crystal structures of the following products are presented: [{Ca{OC(H)Ph(2)}(dipp-nacnac)}(2)], [{Ca{N=C(H)Ph}(dipp-nacnac)}(2)], [{Ca{C(H)=NC(Me)(2)CH(2)C(Me)(3)}(dipp-nacnac)}(2)], [{Ca{C(H)=NCy}(dipp-nacnac)}(2)], [Ca(dipp-nacnac)(thf)](+)[H(2)BC(8)H(14)](-) and [{Ca(OCy)(dipp-nacnac)}(2)]. The generally smooth and clean conversions of 1 with a variety of substrates and the stability of most intermediates against ligand exchange make 1 a valuable key precursor in the syntheses of a wide variety of beta-diketiminate calcium complexes.

The calcium and vitamin D controversy

DEFF Research Database (Denmark)

Abrahamsen, Bo

2017-01-01

Areas of the world where vitamin D levels are low for months of the year and intakes of calcium are high have a high prevalence of osteoporosis and cardiovascular disease. This suggests a public health message of avoiding calcium supplements and increasing vitamin D intake. No message could be more...... welcome as vitamin D can be given as a bolus while calcium must be taken daily and may be poorly tolerated. This approach is based on no evidence from intervention studies. Randomized controlled trials (RCTs) suggest that vitamin D given with calcium elicits a small reduction in fracture risk and deaths....... This has not been demonstrated for D given alone. The cardiovascular safety of calcium and vitamin D (CaD) supplements is difficult to ascertain due to weaknesses in RCT designs and adjudication that cannot be remedied by subanalysis. Moreover, no major new RCTs are in process to provide better evidence...

Calcium as a cardiovascular toxin in CKD-MBD.

Science.gov (United States)

Moe, Sharon M

2017-07-01

Disordered calcium balance and homeostasis are common in patients with chronic kidney disease. Such alterations are commonly associated with abnormal bone remodeling, directly and indirectly. Similarly, positive calcium balance may also be a factor in the pathogenesis of extra skeletal soft tissue and arterial calcification. Calcium may directly affect cardiac structure and function through direct effects to alter cell signaling due to abnormal intracellular calcium homeostasis 2) extra-skeletal deposition of calcium and phosphate in the myocardium and small cardiac arterioles, 3) inducing cardiomyocyte hypertrophy through calcium and hormone activation of NFAT signaling mechanisms, and 4) increased aorta calcification resulting in chronic increased afterload leading to hypertrophy. Similarly, calcium may alter vascular smooth muscle cell function and affect cell signaling which may predispose to a proliferative phenotype important in arteriosclerosis and arterial calcification. Thus, disorders of calcium balance and homeostasis due to CKD-MBD may play a role in the high cardiovascular burden observed in patients with CKD. Published by Elsevier Inc.

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

Effects of Oxcarbazepine and Levetiracetam on Calcium, Ionized Calcium, and 25-OH Vitamin-D3 Levels in Patients with Epilepsy.

Science.gov (United States)

Aksoy, Duygu; Güveli, Betül Tekin; Ak, Pelin Doğan; Sarı, Hüseyin; Ataklı, Dilek; Arpacı, Baki

2016-02-29

The primary objective of the present study was to further elucidate the effects of oxcarbazepine (OXC) and levetiracetam (LEV) monotherapies on the bone health status of patients with epilepsy. This study included 48 patients who attended our epilepsy outpatient clinic, had a diagnosis of epilepsy, and were undergoing either OXC or LEV monotherapy and 42 healthy control subjects. The demographic and clinical features of the patients, including gender, age, onset of disease, daily drug dosage, and duration of disease, were noted. Additionally, the calcium, ionized calcium, and 25-OH vitamin-D3 levels of the participants were prospectively evaluated. The 25-OH vitamin-D3, calcium, and ionized calcium levels of the patients taking OXC were significantly lower than those of the control group. These levels did not significantly differ between the patients taking LEV and the control group, but there was a significant negative relationship between daily drug dose and ionized calcium levels in the LEV patients. In the present study, anti-epileptic drugs altered the calcium, ionized calcium, and 25-OH vitamin-D3 levels of epilepsy patients and resulted in bone loss, abnormal mineralization, and fractures. These findings suggest that the calcium, ionized calcium, and 25-OH vitamin-D3 levels of patients with epilepsy should be regularly assessed.

Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells.

Science.gov (United States)

Carr, Lynn; Bardet, Sylvia M; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P

2018-02-01

Cytosolic, synthetic chemical calcium indicators are typically used to visualise the rapid increase in intracellular calcium ion concentration that follows nanosecond pulsed electric field (nsPEF) application. This study looks at the application of genetically encoded calcium indicators (GECIs) to investigate the spatiotemporal nature of nsPEF-induced calcium signals using fluorescent live cell imaging. Calcium responses to 44kV/cm, 10ns pulses were observed in U87-MG cells expressing either a plasma membrane targeted GECI (GCaMP5-G), or one cytosolically expressed (GCaMP6-S), and compared to the response of cells loaded with cytosolic or plasma membrane targeted chemical calcium indicators. Application of 100 pulses, to cells containing plasma membrane targeted indicators, revealed a wave of calcium across the cell initiating at the cathode side. A similar spatial wave was not observed with cytosolic indicators with mobile calcium buffering properties. The speed of the wave was related to pulse application frequency and it was not propagated by calcium induced calcium release. Copyright © 2017 Elsevier B.V. All rights reserved.

Monitoring the progression of calcium and protein solubilisation as affected by calcium chelators during small-scale manufacture of casein-based food matrices.

Science.gov (United States)

McIntyre, Irene; O'Sullivan, Michael; O'Riordan, Dolores

2017-12-15

Calcium and protein solubilisation during small-scale manufacture of semi-solid casein-based food matrices was investigated and found to be very different in the presence or absence of calcium chelating salts. Calcium concentrations in the dispersed phase increased and calcium-ion activity (A Ca ++ ) decreased during manufacture of the matrices containing calcium chelating salts; with ∼23% of total calcium solubilised by the end of manufacture. In the absence of calcium chelating salts, these concentrations were significantly lower at equivalent processing times and remained unchanged as did A Ca ++ , throughout manufacture. The protein content of the dispersed phase was low (≤3% of total protein), but was significantly higher for matrices containing calcium chelating salts. This study elucidates the critical role of calcium chelating salts in modulating casein hydration and dispersion and gives an indication of the levels of soluble calcium and protein required to allow matrix formation during manufacture of casein-based food structures e.g. processed and analogue cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of nano calcium carbonate and nano calcium citrate on toxicity in ICR mice and on bone mineral density in an ovariectomized mice model

Energy Technology Data Exchange (ETDEWEB)

Huang, Sherry; Chen, Jin Ching; Hsu, Chin Wei; Chang, Walter H, E-mail: whchang@cycu.edu.t [Center for Nano Bioengineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Department of Biomedical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

2009-09-16

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 the present study, we examined whether the bioavailability of calcium carbonate and calcium citrate can be improved by reducing the particle size. The morphology of nano calcium carbonate and nano calcium citrate was characterized by dynamic laser-light scattering (DLS), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The measurements obtained from DLS, FE-SEM and TEM were comparable. Acute and sub-chronic toxicity tests were performed to establish the safety of these products after oral administration. The no-observed-adverse-effect levels of nano calcium carbonate and nano calcium citrate were 1.3 and 2.3 g kg{sup -1} body weight, respectively. The results of our in vivo studies indicate that administering nano calcium carbonate and nano calcium citrate can enhance the serum calcium concentration and maintain the whole-body bone mineral density in ovariectomized mice. These data suggest that nano calcium carbonate and nano calcium citrate are more bioavailable than micro calcium carbonate and micro calcium citrate, respectively.

Calcium and Calcium Supplements: Achieving the Right Balance

Science.gov (United States)

... may have on heart attack risk. A similar controversy surrounds calcium and prostate cancer. Some studies have ... your agreement to the Terms and Conditions and Privacy Policy linked below. Terms and Conditions Privacy Policy ...

External validity of a cardiovascular screening including a coronary artery calcium examination in middle-aged individuals from the general population

DEFF Research Database (Denmark)

Grønhøj, Mette H; Gerke, Oke; Mickley, Hans

2018-01-01

, and the association between coronary artery calcium and cardiovascular events. Design Multi-centre population based study. Methods Randomly selected middle-aged men and women ( N = 1751) free of cardiovascular disease were invited to the examination during 2009-2010. Participation rate in the examination was 70......%. Participants ( n = 1227) and non-participants ( n = 524) were compared regarding: cardiovascular medical treatment, Charlson comorbidity index and socioeconomic status (evaluated by cohabitation, gross income and education). Study endpoints were cardiovascular events and mortality. Results Non-participants had......). Adjusted hazard ratio was 0.90 (95% confidence interval (CI) 0.63-1.37). Among participants, the extent of coronary artery calcium was significantly associated with increased risk of cardiovascular events (hazard ratio 1.92, 95% CI 1.03-3.54, hazard ratio 3.66, 95% CI 1.82-7.32, hazard ratio 6.51, 95% CI 3...

2018-04-25T12:54:54Z https://www.ajol.info/index.php/all/oai oai:ojs ...

African Journals Online (AJOL)

article/33595 2018-04-25T12:54:54Z nifoj:ART Chemical constituents of the solvent extracted and hydrodistilled essential oils of African nutmeg (Monodora myristica) and turmeric (Curcuma domestica) from South West Nigeria Igwe, CC; Essential ...

40 CFR 264.54 - Amendment of contingency plan.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Amendment of contingency plan. 264.54 Section 264.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Contingency Plan and Emergency Procedures § 264.54 Amendment of contingency plan. The contingency plan must be...

Calcium and Bone Metabolism Indices.

Science.gov (United States)

Song, Lu

2017-01-01

Calcium and inorganic phosphate are of critical importance for many body functions, thus the regulations of their plasma concentrations are tightly controlled by the concerted actions of reabsorption/excretion in the kidney, absorption in the intestines, and exchange from bone, the major reservoir for calcium and phosphate in the body. Parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (1,25(OH) 2 D) control calcium homeostasis, whereas PTH, 1,25(OH) 2 D, and bone-derived fibroblast growth factor 23 (FGF 23) control phosphate homeostasis. Hypoparathyroidism can cause hypocalcemia and hyperphosphatemia, whereas deficient vitamin D actions can cause osteomalacia in adults and rickets in children. Hyperparathyroidism, alternatively, can cause hypercalcemia and hypophosphatemia. Laboratory tests of calcium, phosphate, PTH, and 25-hydroxyvitamin D are very useful in the diagnosis of abnormalities associated with calcium and/or phosphate metabolisms. Bone is constantly remodeled throughout life in response to mechanical stress and a need for calcium in extracellular fluids. Metabolic bone diseases such as osteoporosis, osteomalacia in adults or rickets in children, and renal osteodystrophy develop when bone resorption exceeds bone formation. Bone turnover markers (BTM) such as serum N-terminal propeptide of type I procollagen (P1NP) and C-terminal collagen cross-link (CTX) may be useful in predicting future fracture risk or monitoring the response to anti-resorptive therapy. There is a need to standardize sample collection protocols because certain BTMs exhibit large circadian variations and tend to be influenced by food intakes. In the United States, a project to standardize BTM sample collection protocols and to establish the reference intervals for serum P1NP and serum CTX is ongoing. We anticipate the outcome of this project to shine lights on the standardization of BTM assays, sample collection protocols, reference intervals in relation to age, sex, and ethnic

Does calcium constrain reproductive activity in insectivorous bats ...

African Journals Online (AJOL)

Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in ...

Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

Science.gov (United States)

Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

2015-01-01

Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

Calcium phosphates for biomedical applications

Directory of Open Access Journals (Sweden)

Maria Canillas

2017-05-01

Full Text Available The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies.

Calcium phosphates for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.

2017-07-01

The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

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.

40 CFR 61.54 - Sludge sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Sludge sampling. 61.54 Section 61.54... sampling. (a) As an alternative means for demonstrating compliance with § 61.52(b), an owner or operator... days prior to a sludge sampling test, so that he may at his option observe the test. (c) Sludge shall...

Dietary calcium intake and risk of cardiovascular disease, stroke, and fracture in a population with low calcium intake.

Science.gov (United States)

Kong, Sung Hye; Kim, Jung Hee; Hong, A Ram; Cho, Nam H; Shin, Chan Soo

2017-07-01

Background: The role of dietary calcium intake in cardiovascular disease (CVD), stroke, and fracture is controversial. Most previous reports have evaluated populations with high calcium intake. Objective: We aimed to evaluate whether high dietary calcium intake was associated with the risk of CVD, stroke, and fracture in a population with low calcium intake. Design: In a prospective cohort study beginning in 2001 in Ansung-Ansan, Korea, 2158 men and 2153 women aged >50 y were evaluated for all-cause mortality, CVD, stroke, and fractures over a median 9-y follow-up. Results: During follow-up, 242 and 100 deaths, 149 and 150 CVD events, 58 and 82 stroke events, and 211 and 292 incident fractures occurred in men and women, respectively. The first quartiles of energy-adjusted dietary calcium intake were 249 mg/d (IQR: 169 mg/d) in men and 209 mg/d (IQR: 161 mg/d) in women. Both men and women with higher dietary calcium intake tended to have higher fat, protein, sodium, phosphorus, fruit, and vegetable intakes. In men, outcomes were not significantly associated with dietary calcium intake with or without adjustments, and CVD risk tended to increase with increasing energy-adjusted dietary calcium intake, but this was not statistically significant ( P = 0.078 and P = 0.093 with and without adjustment, respectively). In women, CVD risk and dietary calcium intake showed a U-shaped association; the HRs (95% CIs) without adjustment relative to the first quartile were 0.71 (0.47, 1.07), 0.57 (0.36, 0.88), and 0.52 (0.33, 0.83) for quartiles 2, 3, and 4, respectively, and the values after adjustment were 0.70 (0.45, 1.07), 0.51 (0.31, 0.81), and 0.49 (0.29, 0.83) for quartiles 2, 3, and 4, respectively. Conclusion: In Korean women, increased dietary calcium intake was associated with a decreased CVD risk, but it did not influence the risk of stroke or fracture. © 2017 American Society for Nutrition.

Brain calcium - Role in temperature regulation.

Science.gov (United States)

Hanegan, J. L.; Williams, B. A.

1973-01-01

Perfusion of the preoptic-anterior hypothalamus with excess calcium ion in ground squirrels produces a drop in core temperature. The magnitude of the drop is directly dependent on ambient temperature. Respiration, heart rate, and oxygen consumption are also reduced during perfusion of calcium ion. It is concluded that the depression of body temperature during calcium ion perfusion is due to generalized depression of the neurons of the preoptic-anterior hypothalamus.

Solubility and bioavailability of stabilized amorphous calcium carbonate.

Science.gov (United States)

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

2011-02-01

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

Calcium and Nuclear Signaling in Prostate Cancer

OpenAIRE

Ivan V. Maly; Wilma A. Hofmann

2018-01-01

Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR) and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the un...

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

International Nuclear Information System (INIS)

Wolters, G.H.J.; Wiegman, J.B.; Konijnendijk, W.

1982-01-01

Glucose-stimulated 45 calcium uptake and total calcium content of rat pancreatic islets has been studied, using a new fluorometric micro-method to estimate total calcium. Extracellular calcium was separated from incubated tissue by a rapid micro-filtration procedure. Islets incubated up to 60 min with calcium chloride 2.5 mmol/l and glucose 2.5 mmol/l maintained the same calcium content (670 +- 7.5 pmol/μg DNA). When the glucose concentration was raised to 15 mmol/l no change in the total calcium content could be detected. On incubation with glucose 2.5 mmol/l in the absence of calcium, the calcium content decreased to 488 +- 27 pmol/μg DNA. On incubation with 45 calcium chloride 2.5 mmol/l for 5 or 30 min at 2.5 mmol/l glucose, islets exchanged 21 +- 2 and 28 +- 1% of their total calcium content and, at 15 mmol/l glucose, 30 +- 3 and 45 +- 2%, respectively. Thus, islet calcium has a high turn-over rate. Glucose stimulation results in an increase of the calcium uptake without enhancing the total calcium content and hence must increase the calcium-exchangeable pool. (orig.)

Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer.

Science.gov (United States)

Kuga, Milton Carlos; Duarte, Marco Antonio Hungaro; Sant'anna-Júnior, Arnaldo; Keine, Kátia Cristina; Faria, Gisele; Dantas, Andrea Abi Rached; Guiotti, Flávia Angélica

2014-06-01

Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.

First quantification of calcium intake from calcium-dense dairy products in Dutch fracture patients (the Delft cohort study).

Science.gov (United States)

van den Berg, Peter; van Haard, Paul M M; van den Bergh, Joop P W; Niesten, Dieu Donné; van der Elst, Maarten; Schweitzer, Dave H

2014-06-23

Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians). An observational study analyzed dairy calcium intakes of 1526 female and 372 male Dutch fracture patients older than 50. On average, participants reported three dairy servings per day, independently of age, gender or population density. Median calcium intake from dairy was 790 mg/day in females and males. Based on dairy products alone, 11.3% of women and 14.2% of men complied with Dutch recommendations for calcium intake (adults ≤ 70 years: 1100 mg/day and >70 years: 1200 mg/day). After including 450 mg calcium from basic nutrition, compliance raised to 60.5% and 59.1%, respectively, compared to 53.2% in the U.S. cohort. Daily dairy calcium intake is not associated with femoral neck bone mineral density (BMD) T-scores or WHO Fracture Assessment Tool (FRAX) risk scores for major fracture or hip fracture. However, when sub analyzing the male cohort, these associations were weakly negative. The prevalence of maternal hip fracture was a factor for current fracture risks, both in women and men. While daily dairy calcium intake of Dutch fracture patients was well below the recommended dietary intake, it was comparable to intakes in a healthy U.S. cohort. This questions recommendations for adding more additional dairy products to preserve adult skeletal health, particularly when sufficient additional calcium is derived from adequate non-dairy nutrition.

First Quantification of Calcium Intake from Calcium-Dense Dairy Products in Dutch Fracture Patients (The Delft Cohort Study

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Peter van den Berg

2014-06-01

Full Text Available Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians. An observational study analyzed dairy calcium intakes of 1526 female and 372 male Dutch fracture patients older than 50. On average, participants reported three dairy servings per day, independently of age, gender or population density. Median calcium intake from dairy was 790 mg/day in females and males. Based on dairy products alone, 11.3% of women and 14.2% of men complied with Dutch recommendations for calcium intake (adults ≤ 70 years: 1100 mg/day and >70 years: 1200 mg/day. After including 450 mg calcium from basic nutrition, compliance raised to 60.5% and 59.1%, respectively, compared to 53.2% in the U.S. cohort. Daily dairy calcium intake is not associated with femoral neck bone mineral density (BMD T-scores or WHO Fracture Assessment Tool (FRAX risk scores for major fracture or hip fracture. However, when sub analyzing the male cohort, these associations were weakly negative. The prevalence of maternal hip fracture was a factor for current fracture risks, both in women and men. While daily dairy calcium intake of Dutch fracture patients was well below the recommended dietary intake, it was comparable to intakes in a healthy U.S. cohort. This questions recommendations for adding more additional dairy products to preserve adult skeletal health, particularly when sufficient additional calcium is derived from adequate non-dairy nutrition.

19 CFR 151.54 - Testing by Customs laboratory.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Testing by Customs laboratory. 151.54 Section 151.54 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF... Other Metal-Bearing Materials § 151.54 Testing by Customs laboratory. Samples taken in accordance with...

Calcium-sensing receptor gene polymorphism (rs7652589) is associated with calcium nephrolithiasis in the population of Yi nationality in Southwestern China.

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Li, Hao; Zhang, Jianhua; Long, Jiang; Shi, Jiarun; Luo, Yuhui

2018-04-16

The calcium-sensing receptor (CaSR) gene plays an important role in regulating the Ca 2+ balance and reducing the risk for calcium stones. In this study, we evaluated the association of CaSR polymorphisms with calcium nephrolithiasis in the population of Yi nationality in Southwestern China. Biochemical variables were evaluated in 624 calcium nephrolithiasis patients and 470 age-matched healthy controls without a history of nephrolithiasis. CaSR polymorphisms rs7652589, rs1501899, rs1801725 (Ala986Ser), rs1042636 (Arg990Gly) and rs1801726 (Gln1011Glu) were investigated between the calcium nephrolithiasis patients and healthy controls, using direct sequencing. Compared with the healthy controls, serum creatinine and 24-hour urine calcium levels were significantly higher in calcium nephrolithiasis patients. Among these five polymorphisms, the genotypic and allelic frequency distributions of rs7652589 SNP was significantly associated with the risk of calcium nephrolithiasis. However, there were no genotypic or allelic distribution differences for rs1501899, rs1801725, rs1042636, and rs1801726 polymorphisms between calcium nephrolithiasis patients and healthy controls. Moreover, the association between rs7652589 SNP genotypes and the biochemical variables was not found. Our study showed that CaSR rs7652589 polymorphism had a significant effect on the risk of developing calcium nephrolithiasis in the population of Yi nationality in Southwestern China. © 2018 John Wiley & Sons Ltd/University College London.

Lead in calcium supplements (abstract)

International Nuclear Information System (INIS)

Rehman, S.; Khalid, N.

2011-01-01

Lead present in calcium supplements is of grave concern as some lead levels have been measured up to the extent of regulatory limit set by the United States. Calcium supplements inevitably get contaminated with lead as both are naturally occurring elements. Therefore, it is imperative to indicate its level in these supplements in order to create awareness among consumers. In this study, a sophisticated analytical technique, atomic absorption spectrometry was used to analyze Pb contents in 27 commonly consumed Ca supplements manufactured by different national and multinational companies. The daily intake of lead through these supplements was calculated. Only 10% of the calcium supplements analyzed met the criteria of acceptable Pb levels (1.5 mu g/daily dose) in supplements/consumer products set by the United States. It was also found that Pb intake was highest in chelated calcium supplements 28.5 mu g/daily dose, whereas lowest 0.47 mu g/daily dose through calcium supplements with vitamin D formulation. In order to validate our results from the study conducted, IAEA-certified reference material (animal bone, H-5) was analyzed for its Pb levels. The levels of Pb determined were quite in good agreement with the certified values. (author)

Effect of calcium supplements on osteoporosis by using nuclear analytical techniques

International Nuclear Information System (INIS)

Sumin Hu; Xueying Mao; Hong Ouyang

2004-01-01

Neutron activation analysis (NAA) and dual energy X-ray absorptiometry (DEXA) have been used to study the effects of different calcium supplements on osteoporosis, including calcium carbonate, calcium threonate, calcium gluconate, calcium lactate, calcium acetate and a traditional Chinese medicine. Animal test results showed that calcium carbonate, calcium gluconate, calcium acetate and the Chinese medicine notably increased osteoporotic rat's femoral bone mineral density (BMD). Also, calcium carbonate, calcium acetate and the Chinese medicine significantly increased osteoporotic rat's vertebral BMD. But calcium L-threonate and calcium lactate had no such effects. Calcium gluconate, calcium acetate and the Chinese medicine improved the bone mechanical intensity of osteoporotic rats. The results of NAA showed that the loss of elements in spongy bones was more seriously than that in compact bone and was difficult to be improved. (author)

Calcium and Egg Activation in Drosophila

Science.gov (United States)

Sartain, Caroline V.; Wolfner, Mariana F.

2012-01-01

Summary In many animals, a rise in intracellular calcium levels is the trigger for egg activation, the process by which an arrested mature oocyte transitions to prepare for embryogenesis. In nearly all animals studied to date, this calcium rise, and thus egg activation, is triggered by the fertilizing sperm. However in the insects that have been examined, fertilization is not necessary to activate their oocytes. Rather, these insects’ eggs activate as they transit through the female’s reproductive tract, regardless of male contribution. Recent studies in Drosophila have shown that egg activation nevertheless requires calcium and that the downstream events and molecules of egg activation are also conserved, despite the difference in initial trigger. Genetic studies have uncovered essential roles for the calcium-dependent enzyme calcineurin and its regulator calcipressin, and have hinted at roles for calmodulin, in Drosophila egg activation. Physiological and in vitro studies have led to a model in which mechanical forces that impact the Drosophila oocyte as it moves through the reproductive tract triggers the influx of calcium from the external environment, thereby initiating egg activation. Future research will aim to test this model, as well as to determine the spatiotemporal dynamics of cytoplasmic calcium flux and mode of signal propagation in this unique system. PMID:23218670

Effect of different calcium sources on the antioxidant stability of tortilla chips from extruded and nixtamalized blue corn (Zea mays L. flours

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Miguel Ángel Sánchez-Madrigal

2014-03-01

Full Text Available This research aimed to develop tortilla chips (TC high in antioxidants from extruded and nixtamalized blue corn flours prepared with calcium hydroxide Ca(OH2 and calcium lactate C6H10O6Ca. Tortilla chips were made with extruded flours [0.1% Ca(OH2; 0.9% C6H10O6Ca; without calcium] and nixtamalized flours [1% Ca(OH2; 2.95% C6H10O6Ca] using the frying process. Total anthocyanin, total phenolics content, antioxidant activity, color, texture, and oil content were determined. The color of tortilla chips from extruded flours (TCEF showed high values of the parameters a* and b* indicating a reduction in the blue color. These color parameters were significantly different from those observed in tortilla chips from nixtamalized flours (TCNF, which tended to be more blue. The TCEF retained 15% anthocyanins, 34% phenolics, and 54% antioxidant activity. Pearson's correlation analysis indicated that anthocyanins and phenolics correlated significantly with antioxidant activity and color. TCEF with both calcium sources showed higher fracturability compared with that of TCNF. Oil absorption showed an opposite effect, with lower oil content in TCEF. Nixtamalization and extrusion with C6H10O6Ca resulted in flours and TC high in anthocyanins and antioxidant activity, representing an alternative production process for corn snack high in antioxidants.

A study of calcium intake and sources of calcium in adolescent boys and girls from two socioeconomic strata, in Pune, India.

Science.gov (United States)

Sanwalka, Neha J; Khadilkar, Anuradha V; Mughal, M Zulf; Sayyad, Mehmood G; Khadilkar, Vaman V; Shirole, Shilpa C; Divate, Uma P; Bhandari, Dhanshari R

2010-01-01

Adequate intake of calcium is important for skeletal growth. Low calcium intake during childhood and adolescence may lead to decreased bone mass accrual thereby increasing the risk of osteoporotic fractures. Our aim was to study dietary calcium intake and sources of calcium in adolescents from lower and upper economic strata in Pune, India. We hypothesized that children from lower economic strata would have lower intakes of calcium, which would predominantly be derived from non-dairy sources. Two hundred male and female adolescents, from lower and upper economic stratum were studied. Semiquantitative food frequency questionnaire was used to evaluate intakes of calcium, phosphorus, oxalic acid, phytin, energy and protein. The median calcium intake was significantly different in all four groups, with maximum intake in the upper economic strata boys (893 mg, 689-1295) and lowest intake in lower economic strata girls (506 mg, 380-674). The median calcium intake in lower economic strata boys was 767 mg (585-1043) and that in upper economic strata girls was 764 mg (541-959). The main source of calcium was dairy products in upper economic strata adolescents while it was dark green leafy vegetables in lower economic strata adolescents. The median calcium intake was much lower in lower economic strata than in the upper economic strata both in boys and girls. Girls from both groups had less access to dairy products as compared to boys. Measures need to be taken to rectify low calcium intake in lower economic strata adolescents and to address gender inequality in distribution of dairy products in India.

Calcium content of different compositions of gallstones and pathogenesis of calcium carbonate gallstones

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Ji-Kuen Yu

2013-01-01

Conclusion: From our study, we found chronic and/or intermittent cystic duct obstructions and low-grade GB wall inflammation lead to GB epithelium hydrogen secretion dysfunction. Increased calcium ion efflux into the GB lumen combined with increased carbonate anion presence increases SI_CaCO3 from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate.

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. (c...

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. (c...

Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture.

Science.gov (United States)

Mauceri, Daniela; Hagenston, Anna M; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

2015-09-18

Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Calcium homeostasis in diabetes mellitus.

Science.gov (United States)

Ahn, Changhwan; Kang, Ji-Houn; Jeung, Eui-Bae

2017-09-30

Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

Energy Technology Data Exchange (ETDEWEB)

Mishelevich, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail: apelblat@bgu.ac.il

2008-05-15

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution.

Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

International Nuclear Information System (INIS)

Mishelevich, Alexander; Apelblat, Alexander

2008-01-01

The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution

Magnesium-to-calcium ratio in tap water, and its relationship to geological features and the incidence of calcium-containing urinary stones.

Science.gov (United States)

Kohri, K; Kodama, M; Ishikawa, Y; Katayama, Y; Takada, M; Katoh, Y; Kataoka, K; Iguchi, M; Kurita, T

1989-11-01

We examined the relationship among magnesium and calcium content in tap water, the geological features and urinary stone incidence in Japan. The magnesium-to-calcium ratio in tap water correlated negatively with the incidence of urolithiasis. There was no correlation between calcium and magnesium concentration in tap water and urinary stone incidence. Geological features in Japan were classified into 5 groups. The magnesium-to-calcium ratio in the basalt areas was higher than in the other areas, while ratio in the granite areas was low. In the sedimentary rock areas calcium and magnesium concentrations were high; the magnesium-to-calcium ratio in these areas was between those of the basalt and granite areas. The limestone areas had a much higher calcium concentration. The incidence of urinary stones in the sedimentary rock and basalt areas was lower than that of the granite areas, while that in the limestone areas was the highest. Thus, the incidence of urinary stone is related to the magnesium-to-calcium ratio in tap water and the geological area.

Calcium response to vitamin D supplementation

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Francisco R. Spivacow

2018-01-01

Full Text Available Several studies show the importance of serum vitamin D sufficient levels to prevent multiple chronic diseases. However, vitamin D supplementation and its effects on urine calcium excretion remain controversial. The objective of this prospective and interventional study was to evaluate urine calcium excretion in women with normal calciuria or hypercalciuria, once serum vitamin D sufficiency was achieved. We studied 63 women with idiopathic hypercalciuria, (9 with renal lithiasis and 50 normocalciuric women. Both groups had serum vitamin D levels low (deficiency or insufficiency. Baseline urine calcium excretion was measured before being supplemented with vitamin D2 or D3 weekly or vitamin D3 100.000 IU monthly. Once serum vitamin D levels were corrected achieving at least 30 ng/ml, a second urine calcium excretion was obtained. Although in the whole sample we did not observe significant changes in urine calcium excretion according to the way of supplementation, some of those with weekly supplementation had significant higher urine calcium excretion, 19% (n = 12 of hypercalciuric women and 12% (n = 6 of the normocalciuric group. Monthly doses, also showed higher urine calcium excretion in 40% of hypercalciuric women (n = 4/10 and in 44% (n = 4/9 of the renal lithiasis hypercalciuric patients. In conclusion, different ways of vitamin D supplementation and adequate serum levels are safe in most patients, although it should be taken into account a subgroup, mainly with monthly loading doses, that could increase the calciuria significantly eventually rising renal lithiasis risk or bone mass loss, if genetically predisposed.

46 CFR 54.05-16 - Production toughness testing.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Production toughness testing. 54.05-16 Section 54.05-16... Toughness Tests § 54.05-16 Production toughness testing. (a) For vessels of welded construction, production... welding procedures shall be the same as used in the fabrication of the vessel. From each test plate, one...

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

Science.gov (United States)

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

2014-10-01

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

Studies on endogenous circulating calcium entry blocker and stimulator

International Nuclear Information System (INIS)

Pang, P.K.T.; Yang, M.C.M.

1986-01-01

Several synthetic compounds have been studied extensively for their calcium entry blockade and stimulation in smooth muscles. It is hypothesized that there should be endogenous substances which control calcium entry into cells. We recently investigated the effect of some vasoactive hormones on calcium entry. Our studies on rat tail artery helical strip showed that the in vitro vasoconstriction produced by arginine vasopressin (AVP) decreased stepwise with decreasing concentration of both calcium. After exposure of the tail artery to calcium-free Ringer's solution for 1 minute or longer, the tissue lost its ability to respond to AVP. Subsequent addition of calcium to the medium produced immediate contraction. Measurements of low affinity lanthanum resistant pool of calcium with 45 Ca showed that AVP increased calcium uptake by tail artery in a dose-dependent manner. In another study rat tail artery helical strip indicated that the vasorelaxing action of parathyroid hormone (PTH) was related to an inhibition of calcium uptake. AVP or 60 mM potassium chloride increased the low affinity lanthanum resistant pool of calcium in rate tail artery and PTH inhibited the increase. In conclusion, AVP and PTH may behave like endogenous calcium entry stimulator and inhibitor respectively in vascular tissues

47 CFR 54.502 - Supported telecommunications services.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 3 2010-10-01 2010-10-01 false Supported telecommunications services. 54.502 Section 54.502 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES... telecommunications services. For purposes of this subpart, supported telecommunications services provided by...

Diagnosis and assessment of skeletal related disease using calcium 41

Science.gov (United States)

Hillegonds, Darren J [Oakland, CA; Vogel, John S [San Jose, CA; Fitzgerald, Robert L [Encinitas, CA; Deftos, Leonard J [Del Mar, CA; Herold, David [Del Mar, CA; Burton, Douglas W [San Diego, CA

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.

Preliminary characterization of calcium chemical environment in apatitic and non-apatitic calcium phosphates of biological interest by X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Eichert, D.; Salome, M.; Banu, M.; Susini, J.; Rey, C.

2005-01-01

Several reports have mentioned the existence of non-apatitic environments of phosphate and carbonate ions in synthetic and biological poorly crystalline apatites. However there were no direct spectroscopic evidences for the existence of non-apatitic environment of calcium ions. X-ray Absorption Spectroscopy, at the K-edge of calcium, allows the discrimination between different calcium phosphates of biological interest despite great spectral similarities. A primary analysis of the spectra reveals the existence, in synthetic poorly crystalline apatites, of variable features related to the maturation stage of the sample and corresponding to the existence of non-apatitic environments of calcium ions. Although these features can also be found in several other calcium phosphate salts, and do not allow a clear identification of the ionic environments of calcium ions, they give a possibility to directly determine the maturity of poorly crystalline apatite from calcium X-ray Absorption Near Edge Structure spectra

Bell-shaped calcium-response curves of lns(l,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum

Science.gov (United States)

Bezprozvanny, Llya; Watras, James; Ehrlich, Barbara E.

1991-06-01

RELEASE of calcium from intracellular stores occurs by two pathways, an inositol 1,4,5-trisphosphate (InsP3)-gated channel1-3 and a calcium-gated channel (ryanodine receptor)4-6. Using specific antibodies, both receptors were found in Purkinje cells of cerebellum7,8. We have now compared the functional properties of the channels corresponding to the two receptors by incorporating endoplasmic reticulum vesicles from canine cerebellum into planar bilayers. InsP3-gated channels were observed most frequently. Another channel type was activated by adenine nucleotides or caffeine, inhibited by ruthenium red, and modified by ryanodine, characteristics of the ryanodine receptor/channel6. The open probability of both channel types displayed a bell-shaped curve for dependence on calcium. For the InsP3-gated channel, the maximum probability of opening occurred at 0.2 µM free calcium, with sharp decreases on either side of the maximum. Maximum activity for the ryanodine receptor/channel was maintained between 1 and 100 µM calcium. Thus, within the physiological range of cytoplasmic calcium, the InsP3-gated channel itself allows positive feed-back and then negative feedback for calcium release, whereas the ryanodine receptor/channel behaves solely as a calcium-activated channel. The existence in the same cell of two channels with different responses to calcium and different ligand sensitivities provides a basis for complex patterns of intracellular calcium regulation.

Association of estrogen receptor-alpha and vitamin D receptor genotypes with therapeutic response to calcium in postmenopausal Chinese women

Institute of Scientific and Technical Information of China (English)

Zhen-lin ZHANG; Yue-juan QIN; Qi-ren HUANG; Jin-wei HE; Miao LI; Qi ZHOU; Yun-qiu HU; Yu-juan LIU

2004-01-01

AIM: To investigate the correlation between calcium treatment in postmenopausal women and estrogen receptoralpha (ER-alpha) Xba Ⅰ and Pvu Ⅱ genotype and vitamin D receptor (VDR) Apa Ⅰ genotype. METHODS: One hundred fifteen postmenopausal Chinese women of Han population were enrolled and treated with calcichew-D3(1000 mg calcium and 400 U vitamin D3) daily for 1 year. At entry and after 1 year treatment, the bone mineral density (BMD), serum and urinary bone turnover biochemical markers were evaluated. ER-alpha and VDR genotype were analyzed using PCR-restriction fragment length polymorphism. RESULTS: After 1 year of calcium supplementation, a significant increase of BMD and a marked reduction in serum ALP and PTH levels, and a significant increase of serum 25-(OH) vitamin D level were observed (P＜0.01 or P＜0.05). At entry and after 1 year of treatment, no significant association was found between Xba Ⅰ, Pvu Ⅱ, and Apa Ⅰ genotypes and BMD in L1-4,Neck, and Troch, and all bone turnover marker levels. However, the percentage of change (median, QR) in Neck BMD was significantly different in homozygous XX [-4.14 (from -6.54 to -1.34)] in comparison with Xx [1.72(from -1.12 to 3.20)] (P＜0.001) or xx [1.22 (from -1.74 to 3.06)] Xba Ⅰ ER-alpha genotype (P=0.001).CONCLUSION: Women with ER-α Xba Ⅰ genotype XX may have a higher risk of relatively fast bone mass loss in femoral neck after menopause and that they may have a poor responsiveness to calcium supplementation. The changes in BMD are not associated with ER-alpha Pvu Ⅱ genotype and VDR Apa Ⅰ genotype after 1 year of calcium supplementation.

40 CFR 273.54 - Response to releases.

Science.gov (United States)

2010-07-01

... 273.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR UNIVERSAL WASTE MANAGEMENT Standards for Universal Waste Transporters § 273.54 Response to... other residues from universal wastes. (b) A universal waste transporter must determine whether any...

Short-range intercellular calcium signaling in bone

DEFF Research Database (Denmark)

Jørgensen, Niklas Rye

2005-01-01

into biological effects in bone. Intercellular calcium waves are increases in intracellular calcium concentration in single cells, subsequently propagating to adjacent cells, and can be a possible mechanism for the coupling of bone formation to bone resorption. The aim of the present studies was to investigate...... whether bone cells are capable of communicating via intercellular calcium signals, and determine by which mechanisms the cells propagate the signals. First, we found that osteoblastic cells can propagate intercellular calcium transients upon mechanical stimulation, and that there are two principally...... different mechanisms for this propagation. One mechanism involves the secretion of a nucleotide, possibly ATP, acting in an autocrine action to purinergic P2Y2 receptors on the neighboring cells, leading to intracellular IP3 generation and subsequent release of calcium from intracellular stores. The other...

Δ(54) flavor phenomenology and strings

Energy Technology Data Exchange (ETDEWEB)

Carballo-Pérez, Brenda [Instituto de Física, Universidad Nacional Autónoma de México,Apartado Postal 20-364, Ciudad de México 01000 (Mexico); HEBA Ideas S.A. de C.V.,Calculistas 37, Cd. Mx. 09400 (Mexico); Peinado, Eduardo; Ramos-Sánchez, Saúl [Instituto de Física, Universidad Nacional Autónoma de México,Apartado Postal 20-364, Ciudad de México 01000 (Mexico)

2016-12-23

Δ(54) can serve as a flavor symmetry in particle physics, but remains almost unexplored. We show that in a classification of semi-realistic ℤ{sub 3}×ℤ{sub 3} heterotic string orbifolds, Δ(54) turns out to be the most natural flavor symmetry, providing additional motivation for its study. We revisit its phenomenological potential from a low-energy perspective and subject to the constraints of string models. We find a model with Δ(54) arising from heterotic orbifolds that leads to the Gatto-Sartori-Tonin relation for quarks and charged-leptons. Additionally, in the neutrino sector, it leads to a normal hierarchy for neutrino masses and a correlation between the reactor and the atmospheric mixing angles, the latter taking values in the second octant and being compatible at three sigmas with experimental data.

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

Science.gov (United States)

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 c...

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

Relation of thoracic aortic and aortic valve calcium to coronary artery calcium and risk assessment.

Science.gov (United States)

Wong, Nathan D; Sciammarella, Maria; Arad, Yadon; Miranda-Peats, Romalisa; Polk, Donna; Hachamovich, Rory; Friedman, John; Hayes, Sean; Daniell, Anthony; Berman, Daniel S

2003-10-15

Aortic calcium, aortic valve calcium (AVC), and coronary artery calcium (CAC) have been associated with cardiovascular event risk. We examined the prevalence of thoracic aortic calcium (TAC) and AVC in relation to the presence and extent of CAC, cardiovascular risk factors, and estimated risk of coronary heart disease (CHD). In 2,740 persons without known CHD aged 20 to 79 years, CAC was assessed by electron beam- or multidetector-computed tomography. We determined the prevalence of TAC and AVC in relation to CAC, CHD risk factors, and predicted 10-year risk of CHD. A close correspondence of TAC and AVC was observed with CAC. TAC and AVC increased with age; by the eighth decade of life, the prevalence of TAC was similar to that of CAC (>80%), and 36% of men and 24% of women had AVC. Age, male gender, and low-density lipoprotein cholesterol were directly related to the likelihood of CAC, TAC, and AVC; higher diastolic blood pressure and cigarette smoking additionally predicted CAC. Body mass index and higher systolic and lower diastolic blood pressures were also related to TAC, and higher body mass index and lower diastolic blood pressure were related to AVC. Calculated risk of CHD increased with the presence of AVC and TAC across levels of CAC. TAC and AVC provided incremental value over CAC in association with the 10-year calculated risk of CHD. If longitudinal studies show an incremental value of aortic and aortic valve calcium over that of CAC for prediction of cardiovascular events, future guidelines for risk assessment incorporating CAC assessment may additionally incorporate the measurement of aortic and/or aortic valve calcium.

Impact of calcium overload on bone and mineral metabolism at 55 hemodialysis centers in Lima

Directory of Open Access Journals (Sweden)

Pedro Méndez-Chacón

2018-05-01

Full Text Available Background: Mineral and bone metabolism disorders are common complications in hemodialysis patients that present significant geographical variability. Objectives: The objective of this study was to assess these disorders for the first time in hemodialysis patients from Peru. Methods: The study included 1551 hemodialysis patients from 55 centers affiliated with the Social Health System of Peru in the city of Lima. Demographic data, comorbidities, treatments and biochemical parameters were collected from each patient. Serum calcium, phosphorus and PTH levels were categorized according to the recommended ranges in the KDOQI and KDIGO guidelines. Results: The mean age of the patients was 59.5 ± 15.6 years, with a mean time on hemodialysis of 58.0 ± 54.2 months. All patients were dialyzed with a calcium concentration in the dialysis fluid of 3.5 mEq/l and 68.9% of patients were prescribed phosphate-binding agents (98.4% of them calcium carbonate. A high percentage of patients showed serum calcium above, and serum phosphorus below, the recommended ranges in the KDOQI guidelines (32.8% and 37.3%, respectively. More than half of the patients had serum PTH values below the recommended ranges of both the KDOQI and KDIGO guidelines (56.4% and 51.6%, respectively. Conclusions: Patients included in this study were younger than those from other studies and showed both hypophosphataemia and suppressed PTH, probably due to an excessive calcium overload through dialysis fluid and the use of calcium-containing phosphate binding agents. Resumen: Antecedentes: Las alteraciones del metabolismo óseo y mineral son complicaciones frecuentes de los pacientes de hemodiálisis que presentan una gran variabilidad geográfica. Objetivos: El objetivo del presente estudio fue evaluar por primera vez dichas alteraciones en pacientes de hemodiálisis de Perú. Métodos: El estudio incluyó 1.551 pacientes de hemodiálisis de 55 centros concertados con el seguro social

Direct transformation of calcium sulfite to {alpha}-calcium sulfate hemihydrate in a concentrated Ca-Mg-Mn chloride solution under atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Baohong Guan; Hailu Fu; Jie Yu; Guangming Jiang; Bao Kong; Zhongbiao Wu [Zhejiang University, Hangzhou (China). Department of Environmental Engineering

2011-01-15

Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing {alpha}-calcium sulfate hemihydrate ({alpha}-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to {alpha}-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl{sub 2} solution containing Mg{sup 2+} and Mn{sup 2+} at 95{sup o}C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of {alpha}-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with {alpha}-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of {alpha}-HH. 36 refs., 10 figs., 1 tab.

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.

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

Science.gov (United States)

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

2014-01-01

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

Vitamin D, Calcium, and Bone Health

Science.gov (United States)

... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health Download PDFs English ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

Properties of calcium silicate-monobasic calcium phosphate materials for endodontics containing tantalum pentoxide and zirconium oxide.

Science.gov (United States)

Zamparini, Fausto; Siboni, Francesco; Prati, Carlo; Taddei, Paola; Gandolfi, Maria Giovanna

2018-05-08

The aim of the study was to evaluate chemical-physical properties and apatite-forming ability of three premixed calcium silicate materials containing monobasic calcium phosphate (CaH 4 P 2 O 8 ) bioceramic, tantalum pentoxide and zirconium oxide, recently marketed for endodontics (TotalFill BC-Sealer, BC-RRM-Paste, BC-RRM-Putty). Microchemical and micromorphological analyses, radiopacity, initial and final setting times, calcium release and alkalising activity were tested. The nucleation of calcium phosphates (CaPs) and/or apatite after 28 days ageing was evaluated by ESEM-EDX and micro-Raman spectroscopy. BC-Sealer and BC-RRM-Paste showed similar initial (23 h), prolonged final (52 h) setting times and good radiopacity (> 7 mm Al); BC-RRM-Putty showed fast initial (2 h) and final setting times (27 h) and excellent radiopacity (> 9 mm Al). All materials induced a marked alkalisation (pH 11-12) up to 28 days and showed the release of calcium ions throughout the entire test period (cumulative calcium release 641-806 ppm). After 28 days ageing, a well-distributed mineral layer was present on all samples surface; EDX demonstrated relevant calcium and phosphorous peaks. B-type carbonated apatite and calcite deposits were identified by micro-Raman spectroscopy on all the 28-day-aged samples; the deposit thickness was higher on BC-RRM-Paste and BC-RRM-Putty, in agreement with calcium release data. These materials met the required chemical and physical standards and released biologically relevant ions. The CaSi-CaH 4 P 2 O 8 system present in the materials provided Ca and OH ions release with marked abilities to nucleate a layer of B-type carbonated apatite favoured/accelerated by the bioceramic presence. The ability to nucleate apatite may lead many clinical advantages: In orthograde endodontics, it may improve the sealing ability by the deposition of CaPs at the material-root dentine interface, and in endodontic surgery, it could promote bone and

Antagonist effects of calcium on borosilicate glass alteration

Energy Technology Data Exchange (ETDEWEB)

Mercado-Depierre, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Angeli, F., E-mail: frederic.angeli@cea.fr [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Frizon, F. [CEA Marcoule, DTCD SECM LP2C, 30207 Bagnols sur Cèze (France); Gin, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France)

2013-10-15

Graphical abstract: Display Omitted -- Highlights: •Kinetic study of glass alteration is investigated in calcium-enriched solutions. •New insights into silicon–calcium interactions in glass/cement systems are proposed. •Glass alteration is controlled by pH, Ca concentration and reaction progress. •Evidence of antagonist effects according to the importance of these parameters. -- Abstract: Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon–calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass–cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C–S–H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon–calcium interactions on glass durability and open the way for a better understanding of glass–cement mixing in civil engineering applications as well as in nuclear waste storage.

Antagonist effects of calcium on borosilicate glass alteration

International Nuclear Information System (INIS)

Mercado-Depierre, S.; Angeli, F.; Frizon, F.; Gin, S.

2013-01-01

Graphical abstract: Display Omitted -- Highlights: •Kinetic study of glass alteration is investigated in calcium-enriched solutions. •New insights into silicon–calcium interactions in glass/cement systems are proposed. •Glass alteration is controlled by pH, Ca concentration and reaction progress. •Evidence of antagonist effects according to the importance of these parameters. -- Abstract: Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon–calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass–cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C–S–H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon–calcium interactions on glass durability and open the way for a better understanding of glass–cement mixing in civil engineering applications as well as in nuclear waste storage

An improved kilogram-scale preparation of atorvastatin calcium.

Science.gov (United States)

Novozhilov, Yuri V; Dorogov, Mikhail V; Blumina, Maria V; Smirnov, Alexey V; Krasavin, Mikhail

2015-01-01

If literature protocols are followed, conversion of an advanced ketal ester intermediate (available in kilogram quantities via a published Paal-Knorr synthesis) to cholesterol-lowering drug atorvastatin calcium is hampered by several process issues, particularly at the final stage where the hemi-calcium salt is obtained. We developed a high-yielding synthesis of atorvastatin calcium salt on 7 kg scale that affords >99.5% product purities by introducing the following key improvements: i. isolating the pure product of the ketal deprotection step as crystalline solid, and ii. using a convenient ethyl acetate extraction procedure to isolate the pure atorvastatin calcium at the ester hydrolysis and counter-ion exchange step. The convenient and operationally simple conversion of an advanced intermediate of atorvastatin to the clinically used hemi-calcium salt form of the drug that is superior to the methods obtainable from the literature is now available to facilitate the production of atorvastatin calcium on industrial scale. Graphical abstractStepwise ketal and tert-butyl ester group hydrolysis and a modified work-up protocol lead to a more convenient preparation of API-grade atorvastatin calcium.

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

28 CFR 90.54 - Allocation of funds.

Science.gov (United States)

2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Allocation of funds. 90.54 Section 90.54 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) VIOLENCE AGAINST WOMEN Indian Tribal Governments... number of awards. The selection process will be sensitive to the differences among tribal governments and...

7 CFR 925.54 - Special purpose shipments.

Science.gov (United States)

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Special purpose shipments. 925.54 Section 925.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing... entering the channels of trade for other than the specific purposes authorized by this section. Inspection...

47 CFR 54.504 - Requests for services.

Science.gov (United States)

2010-10-01

... acknowledge that failure to do so may result in denial of discount funding and/or recovery of funding. (ix... 47 Telecommunication 3 2010-10-01 2010-10-01 false Requests for services. 54.504 Section 54.504 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL...

Analysis of calcium-induced conformational changes in calcium-binding allergens and quantitative determination of their IgE binding properties.

Science.gov (United States)

Parody, Nuria; Fuertes, Miguel Angel; Alonso, Carlos; Pico de Coaña, Yago

2013-01-01

The polcalcin family is one of the most epidemiologically relevant families of calcium-binding allergens. Polcalcins are potent plant allergens that contain one or several EF-hand motifs and their allergenicity is primarily associated with the Ca(2+)-bound form of the protein. Conformation, stability, as well as IgE recognition of calcium-binding allergens greatly depend on the presence of protein-bound calcium ions. We describe a protocol that uses three techniques (SDS-PAGE, circular dichroism spectroscopy, and ELISA) to describe the effects that calcium has on the structural changes in an allergen and its IgE binding properties.

Comparison of clastogen-induced gene expression profiles in wild-type and DNA repair-deficient Rad54/Rad54B cells

Directory of Open Access Journals (Sweden)

van Benthem Jan

2010-01-01

Full Text Available Abstract Background Previously we found that Rad54/Rad54B cells are more sensitive towards mitomycin C (MMC as compared to wild-type (WT cells. This difference in sensitivity was absent upon exposure to other clastogens like bleomycin (BLM and γ-radiation. In order to get further insight into possible underlying mechanisms, gene expression changes in WT and Rad54/Rad54B MEFs (mouse embryonic fibroblasts after exposure to the clastogens MMC and BLM were investigated. Exposures of these cells to mutagens (N-ac-AAF and ENU and vehicle were taken as controls. Results Most exposures resulted in an induction of DNA damage signaling and apoptosis genes and a reduced expression of cell division genes in cells of both genotypes. As expected, responses to N-ac-AAF were very similar in both genotypes. ENU exposure did not lead to significant gene expression changes in cells of both genotypes, presumably due to its short half-life. Gene expression responses to clastogens, however, showed a genotype-dependent effect for BLM and MMC. MMC treated Rad54/Rad54B MEFs showed no induction of p53-signaling, DNA damage response and apoptosis as seen for all the other treatments. Conclusion These data support our finding that different types of clastogens exist and that responses to these types depend on the DNA repair status of the cells.

Calcium and vitamin D for bone health in adults

Science.gov (United States)

The calcium intake requirement is challenging to determine, and the IOM recommendations are based largely on calcium balance studies. The IOM recommends a calcium intake of 1000-1200 mg per day for older adults to support the preservation of bone mass. Food sources of calcium are preferred because h...

Inotropic effect, binding properties, and calcium flux effects of the calcium channel agonist CGP 28392 in intact cultured embryonic chick ventricular cells

International Nuclear Information System (INIS)

Laurent, S.; Kim, D.; Smith, T.W.; Marsh, J.D.

1985-01-01

CGP 28392 is a recently described dihydropyridine derivative with positive inotropic properties. To study the mechanism of action of this putative calcium channel agonist, we have related the effects of CGP 28392 on contraction (measured with an optical video system) and radioactive calcium uptake to ligand-binding studies in cultured, spontaneously beating chick embryo ventricular cells. CGP 28392 produced a concentration-dependent increase in amplitude and velocity of contraction (EC 50 = 2 x 10(-7) M; maximum contractile effect = 85% of the calcium 3.6 mM response). Nifedipine produced a shift to the right of the concentration-effect curve for CGP 28392 without decreasing the maximum contractile response, suggesting competitive antagonism (pA2 = 8.3). Computer analysis of displacement of [ 3 H]nitrendipine binding to intact heart cells by unlabeled CGP 28392 indicated a K /sub D/ = 2.2 +/- 0.95 x 10(-7) M, in good agreement with the EC 50 for the inotropic effect. CGP 28392 increased the rate of radioactive calcium influx (+39% at 10 seconds) without altering beating rate, while nifedipine decreased radioactive calcium influx and antagonized the CGP 28392-induced increase in calcium influx. Our results indicate that, in intact cultured myocytes, CGP 28392 acts as a calcium channel agonist and competes for the dihydropyridine-binding site of the slow calcium channel. In contrast to calcium channel blockers, CGP 28392 increases calcium influx and enhances the contractile state

The effect of radiopacifiers agents on pH, calcium release, radiopacity, and antimicrobial properties of different calcium hydroxide dressings.

Science.gov (United States)

Ordinola-Zapata, Ronald; Bramante, Clovis Monteiro; García-Godoy, Franklin; Moldauer, Bertram Ivan; Gagliardi Minotti, Paloma; Tercília Grizzo, Larissa; Duarte, Marco Antonio Hungaro

2015-07-01

The aim of this study was to evaluate the antimicrobial activity, pH level, calcium ion release, and radiopacity of calcium hydroxide pastes associated with three radiopacifying agents (iodoform, zinc oxide, and barium sulfate). For the pH and calcium release tests, 45 acrylic teeth were utilized and immersed in ultrapure water. After 24 h, 72 h, and 7 days the solution was analyzed by using a pH meter and an atomic absorption spectrophotometer. Polyethylene tubes filled with the pastes were used to perform the radiopacity test. For the antimicrobial test, 25 dentin specimens were infected intraorally in order to induce the biofilm colonization and treated with the pastes for 7 days. The Live/Dead technique and a confocal microscope were used to obtain the ratio of live cells. Parametric and nonparametric statistical tests were performed to show differences among the groups (P calcium release test on the 7th day (P > 0.05). The calcium hydroxide/iodoform samples had the highest radiopacity and antimicrobial activity against the biofilm-infected dentin in comparison to the other pastes (P Calcium hydroxide mixed with 17% iodoform and 35% propylene glycol into a paste had the highest pH, calcium ion release, radiopacity, and the greatest antimicrobial action versus similar samples mixed with BaSO4 or ZnO. © 2015 Wiley Periodicals, Inc.

9 CFR 54.5 - Certification by owners.

Science.gov (United States)

2010-01-01

... review upon request by a State or APHIS representative all bills of sale, pedigree registration... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Certification by owners. 54.5 Section 54.5 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF...

First Quantification of Calcium Intake from Calcium-Dense Dairy Products in Dutch Fracture Patients (The Delft Cohort Study)

OpenAIRE

van den Berg, Peter; van Haard, Paul M. M.; van den Bergh, Joop P. W.; Niesten, Dieu Donné; van der Elst, Maarten; Schweitzer, Dave H.

2014-01-01

Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians). An observational study analyzed dairy calcium intakes of 1526 female and 372 ...

47 CFR 17.54 - Rated lamp voltage.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Rated lamp voltage. 17.54 Section 17.54... voltage. To insure the necessary lumen output by obstruction lights, the rated voltage of incandescent lamps used shall correspond to be within 3 percent higher than the voltage across the lamp socket during...

Retention of zinc and calcium from the human colon

International Nuclear Information System (INIS)

Sandstroem, B.C.; Cederblad, A.; Kivistoe, B.S.; Stenquist, B.; Andersson, H.

1986-01-01

Colonic retention of zinc and calcium was studied after installation during colonoscopy of 30 mumol of zinc and 6.4 mmol of calcium labeled with 65 Zn and 47 Ca, and measurement of the whole-body retention of the radionuclides. After cecal installation in nine patients, retention (day 13) of zinc was 3.5 +/- 2.1% (mean +/- SD) and of calcium 3.5 +/- 2.7%. The calculated mean absorption was 4.1% for zinc and 14.1% for calcium. Application at the hepatic flexure in four patients resulted in a mean retention (day 13) of 1.2% for zinc and 0.6% for calcium. Under prevailing conditions, colonic absorption of zinc is relatively small, compared to the uptake after oral administration. Colonic absorption of calcium could, however, account for a substantial part of the total calcium uptake

Deposition of strontium and calcium in snail shell

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, Jr, G M; Nelson, D J; Gardiner, D A

1965-07-03

The relative effects of strontium and calcium concentrations in the environment on their uptake and incorporation into snail shell were investigated. /sup 45/Ca and /sup 85/Sr were used as tracers and specific activities were used to determine deposition. Data are presented in tables and graphs. Deposition of both calcium and strontium in the snail shell depended primarily on the respective concentrations of these elements in the immediate environment. A slight effect of strontium on calcium deposition was observed. There was found to be a minimum strontium deposition for various combinations of strontium and calcium in the environment. It was concluded that strontium uptake is more closely associated with environmental strontium concentrations than with calcium concentrations.

Oligofructose stimulates calcium absorption in adolescents

NARCIS (Netherlands)

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

1999-01-01

Background: In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects. Objective: The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents. Design:

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...

Intact calcium signaling in adrenergic-deficient embryonic mouse hearts.

Science.gov (United States)

Peoples, Jessica N; Taylor, David G; Katchman, Alexander N; Ebert, Steven N

2018-01-22

Mouse embryos that lack the ability to produce the adrenergic hormones, norepinephrine (NE) and epinephrine (EPI), due to disruption of the dopamine beta-hydroxylase (Dbh -/- ) gene inevitably perish from heart failure during mid-gestation. Since adrenergic stimulation is well-known to enhance calcium signaling in developing as well as adult myocardium, and impairments in calcium signaling are typically associated with heart failure, we hypothesized that adrenergic-deficient embryonic hearts would display deficiencies in cardiac calcium signaling relative to adrenergic-competent controls at a developmental stage immediately preceding the onset of heart failure, which first appears beginning or shortly after mouse embryonic day 10.5 (E10.5). To test this hypothesis, we used ratiometric fluorescent calcium imaging techniques to measure cytosolic calcium transients, [Ca 2+ ] i in isolated E10.5 mouse hearts. Our results show that spontaneous [Ca 2+ ] i oscillations were intact and robustly responded to a variety of stimuli including extracellular calcium (5 mM), caffeine (5 mM), and NE (100 nM) in a manner that was indistinguishable from controls. Further, we show similar patterns of distribution (via immunofluorescent histochemical staining) and activity (via patch-clamp recording techniques) for the major voltage-gated plasma membrane calcium channel responsible for the L-type calcium current, I Ca,L , in adrenergic-deficient and control embryonic cardiac cells. These results demonstrate that despite the absence of vital adrenergic hormones that consistently leads to embryonic lethality in vivo, intracellular and extracellular calcium signaling remain essentially intact and functional in embryonic mouse hearts through E10.5. These findings suggest that adrenergic stimulation is not required for the development of intracellular calcium oscillations or extracellular calcium signaling through I Ca,L and that aberrant calcium signaling does not likely contribute

Calcium binding to low molecular weight compounds and health promoting products

DEFF Research Database (Denmark)

Vavrusova, Martina

absorption. Therefore, calcium as an essential nutrient should not be underestimated in our diet. Milk and dairy products are good sources of bioavailable calcium due to specific protein binding. Other sources of calcium, apart from a balanced and healthy diet, are calcium supplements and calcium fortified...... food. Therefore, an understanding of the basic chemistry of calcium binding to low molecular weight compounds can contribute to a general knowledge about calcium bioavailability and also to product improvement. Calcium precipitation with palmitate was described by a first-order reaction for conditions...... of excess calcium in neutral aqueous solutions with a stoichiometry Ca:Pal lower than 1:2. Increasing pH during aging of the precipitate and solubility product determination lead to a suggestion of an initial precipitation of calcium hydroxy palmitate as a possible precursor phase. The binding of calcium...

40 CFR 205.54-2 - Sound data acquisition system.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Sound data acquisition system. 205.54-2 Section 205.54-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Medium and Heavy Trucks § 205.54-2 Sound...

Roles of calcium and IP3 in impaired colon contractility of rats following multiple organ dysfunction syndrome

Directory of Open Access Journals (Sweden)

C. Zheyu

2007-10-01

Full Text Available The purpose of the present study was to explore changes in rat colon motility, and determine the roles of calcium and inositol (1,4,5-triphosphate (IP3 in colon dysmotility induced by multiple organ dysfunction syndrome (MODS caused by bacteria peritonitis. The number of stools, the contractility of the muscle strips and the length of smooth muscle cells (SMC in the colon, the concentration of calcium and IP3 in SMC, and serum nitric oxide were measured. Number of stools, fecal weight, IP3 concentration in SMC and serum nitric oxide concentration were 0.77 ± 0.52 pellets, 2.51 ± 0.39 g, 4.14 ± 2.07 pmol/tube, and 113.95 ± 37.89 µmol/L, respectively, for the MODS group (N = 11 vs 1.54 ± 0.64 pellets, 4.32 ± 0.57 g, 8.19 ± 3.11 pmol/tube, and 37.42 ± 19.56 µmol/L for the control group (N = 20; P < 0.05. After treatment with 0.1 mM acetylcholine and 0.1 M potassium chloride, the maximum contraction stress of smooth muscle strips, the length of SMC and the changes of calcium concentration were 593 ± 81 and 458 ± 69 g/cm³, 48.1 ± 11.8 and 69.2 ± 15.7 µM, 250 ± 70 and 167 ± 48%, respectively, for the control group vs 321 ± 53 and 284 ± 56 g/cm³, 65.1 ± 18.5 and 87.2 ± 23.7 µM, 127 ± 35 and 112 ± 35% for the MODS group (P < 0.05. Thus, colon contractility was decreased in MODS, a result possibly related to reduced calcium concentration and IP3 in SMC.

226Ra, 210Pb and calcium in eyes of long-term radium cases

International Nuclear Information System (INIS)

Holtzman, R.B.; Sha, J.Y.; Plondke, N.J.

1978-01-01

It is known that dogs injected with radium accumulate a significant fraction of this element in the eye, with consequent radiation damage. We are interested in looking for similar concentrations in the human eye. An eye from each of two radium cases (01-144 and 01-017) with body burdens of 690 and 1210 nCi 226 Ra, respectively, was analyzed for 226 Ra, 210 Pb and calcium. The total amounts in the eyes were 1.80 pCi 226 Ra, 1.3 pCi 210 Pb and 2.3 mg of calcium in Case 01-144 and 5.4 pCi 226 Ra, 3.6 pCi 210 Pb and 14.2 mg of calcium in Case 01-017. For the latter case the eye was dissected and showed the highest 226 Ra concentrations (on a wet weight basis) in the choroid (3.8 pCi/g), sclera (3.4 pCi/g) and iris (2.9 pCi/g). The radium content was 2.7 x 10 -4 % to 4.7 x 10 -4 % of the total body content at 50 to 55 years after first exposure. The 226 Ra/Ca ratios in the whole eye were 1/3 to 1/4 those in the whole body, but that for the choroid from the dissected eye was identical to that of the whole body. For 210 Pb the concentrations in the various parts of the eye were similar to and correlated with those of the 226 Ra. The 210 Pb/Ca ratios in the eye are comparable to those of the whole body, which indicates that the eye concentrates 210 Pb relative to 226 Ra. These data will be compared to those from the dog and the differences will be discussed. (author)

Calmodulin immunolocalization to cortical microtubules is calcium independent

Energy Technology Data Exchange (ETDEWEB)

Fisher, D.D.; Cyr, R.J.

1992-12-31

Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 {mu}M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 {mu}M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

Calmodulin immunolocalization to cortical microtubules is calcium independent

Energy Technology Data Exchange (ETDEWEB)

Fisher, D.D.; Cyr, R.J.

1992-01-01

Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 [mu]M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 [mu]M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

Electrophysical properties of calcium vanadates

International Nuclear Information System (INIS)

Krasnenko, T.I.; Fotiev, A.A.

1983-01-01

Electrophysical properties of calcium vanadates are studied for the case of alteration of external parameters of the medium (PO 2 , T). It is lshown that structural transformations bring about changes in the nature of electrophysical properties of Ca 2 V 2 O 7 , Ca 3 (VO 4 ) 2 , this being the reason for charge redistribution in anion groupings. It is obvious, that the general conductivity of calcium methavanadate is mainly caused by ion transport. Ca(VO 3 ) 2 possesses amphoteric character of semiconducting properties: the type of conductivity changes from ''p'' to ''n'' with temperature increase. Polytherms of conductivity and sums of ion numbers of Ca 2 V 2 O 7 transition are given. It is established that calcium pyrovanadate has a mixed electron-ion conductivity

1 CFR 5.4 - Publication not authorized.

Science.gov (United States)

2010-01-01

... 1 General Provisions 1 2010-01-01 2010-01-01 false Publication not authorized. 5.4 Section 5.4... Publication not authorized. (a) Chapter 15 of title 44, United States Code, does not apply to treaties...) Chapter 15 of title 44, United States Code, prohibits the publication in the Federal Register of comments...

Effect of zinc supplements on the intestinal absorption of calcium

International Nuclear Information System (INIS)

Spencer, H.; Rubio, N.; Kramer, L.; Norris, C.; Osis, D.

1987-01-01

Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca-47 and determining plasma levels and urinary and fecal excretions of Ca-47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake

Disponibilidade biológica e exigências de cálcio em eqüinos em crescimento recebendo dietas com diferentes níveis de cálcio Biological availability and calcium requirements of growing equines receiving diets with different calcium levels

Directory of Open Access Journals (Sweden)

Carlos Eduardo Furtado

2009-03-01

Full Text Available Estudou-se o metabolismo de cálcio em eqüinos em crescimento recebendo dietas com diversos níveis desse mineral. Utilizaram-se 12 machos, com média de 12 meses de idade e peso vivo médio de 221,0 kg, mantidos com três dietas com 0,15; 0,45; ou 0,75 de cálcio e 0,23% de fósforo, constituindo um delineamento inteiramente casualizado, com três níveis de cálcio e quatro repetições. Foram injetados em cada animal, via jugular direita, os volumes de uma seringa, correspondentes a 7,4 MBq de 45Ca (CaCl2. Após a injeção, foram colhidas amostras (10 mL de sangue, via jugular esquerda, aos 5 minutos, 1, 2, 4, 6, 24, 48, 72, 96, 120 e 144 horas. As fezes foram colhidas diariamente pela manhã, a partir de 24 horas após a aplicação do radionuclídeo até o sétimo dia e uma alíquota de 5% do total diário excretado foi colhida e armazenada em congelador para posterior análise. O mesmo procedimento das fezes foi adotado para a urina, quando foram colhidas amostras de 1% do volume total diário. Os níveis de cálcio plasmático, cálcio total na urina e cálcio endógeno nas fezes não diferiram entre os níveis de cálcio com valores médios de 11,76; 5,54 e 20,86 mg/kgPV/dia, respectivamente. A disponibilidade biológica de cálcio (média de 81,71% também não diferiu entre os níveis de cálcio. As regressões lineares entre níveis de cálcio na dieta e cálcio total ingerido, cálcio absorvido, cálcio total nas fezes e cálcio retido foram expressas, respectivamente pelas equações: y=10,7+2,78x r²=1,0; y=12,41+2,24x r²=0,99; y=5,97+0,92x r²=0,93 e y=6,4+1,70x r²=0,94, com médias de, respectivamente, 135,80; 113,21; 47,37 e 82,90 mg/kgPV/dia.The objective of this work was to study the calcium metabolism in growing equines receiving diets with different calcium levels. Twelve male were used, with average age of twelve months and average alive weight of 221,0 kg. The treatments consisted of three diets, composed for

Evaluation of ear skin temperature as a cow-side test to predict postpartum calcium status in dairy cows.

Science.gov (United States)

Venjakob, P L; Borchardt, S; Thiele, G; Heuwieser, W

2016-08-01

Subclinical hypocalcemia is considered a gateway disease that increases susceptibility to other metabolic and infectious diseases in transition dairy cows. In the absence of a cow-side test, however, it is difficult to identify hypocalcemic cows. The objective of this study was to evaluate ear skin temperature as a diagnostic predictor of serum calcium concentration. We conducted a cross-sectional study on 7 commercial dairy farms, involving 251 cows 0 to 48h after calving. Skin temperature of the ears (STEar) was scored manually by palpating both ears. An infrared thermometer was used to measure ear temperature, skin temperature on the coxal tuber (STCox), and ambient temperature. Rectal temperature was measured using a digital thermometer. A blood sample was drawn to determine serum calcium concentration. Hypocalcemia was defined as serum calcium below 2.0mmol/L, irrespective of clinical symptoms. Serum calcium concentration cows in first, second, third, and fourth or greater lactation, respectively. None of the cows in first and second lactation had clinical milk fever. The prevalence of clinical milk fever was 6.0 and 20.3% for cows in their third and fourth or greater lactation, respectively. A decrease in ear temperature of 0.39°C [95% confidence interval (CI): 0.25-0.54] was associated with a decrease of 0.1mmol/L in serum calcium concentration. Ambient temperature, however, was a major confounder for ear temperature. With an increase in ambient temperature of 1°C, STEar rose by 0.78°C (95% CI: 0.67-0.90). Hypothermia was more pronounced in clinical milk fever (median 21.8°C; interquartile range 14.7-27.0°C) compared with subclinical hypocalcemia (median 27.6°C, interquartile range 22.1-30.8°C). All temperature estimates had only accurate test characteristics based on their area under the curve for prediction of subclinical hypocalcemia (area under the curve for STEar, STCox, and rectal temperature were 0.641, 0.668, and 0.606, respectively) when cows

21 CFR 172.715 - Calcium lignosulfonate.

Science.gov (United States)

2010-04-01

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.715 Calcium lignosulfonate. Calcium lignosulfonate may be...

In vivo calcium metabolism by IRMS

Science.gov (United States)

Public policy initiatives related to enhancing the health of populations, increasingly seek to identify meaningful biological outcomes on which to determine age-related nutritional requirements. For calcium, the primary outcome of interest is the availability of calcium in the diet for bone formatio...

9 CFR 54.3 - Animals eligible for indemnity payments.

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2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Animals eligible for indemnity payments. 54.3 Section 54.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... SCRAPIE Scrapie Indemnification Program § 54.3 Animals eligible for indemnity payments. (a) Indemnity may...

9 CFR 54.7 - Procedures for destruction of animals.

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2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Procedures for destruction of animals. 54.7 Section 54.7 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT... SCRAPIE Scrapie Indemnification Program § 54.7 Procedures for destruction of animals. (a) Scrapie-positive...

Calcium - urine

Science.gov (United States)

... Female urinary tract Male urinary tract Calcium urine test References Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology . 13th ed. Philadelphia, PA: Elsevier; ...

Calcium-dependent but calmodulin-independent protein kinase from soybean

International Nuclear Information System (INIS)

Harmon, A.C.; Putnam-Evans, C.; Cormier, M.J.

1987-01-01

A calcium-dependent protein kinase activity from suspension-cultured soybean cells (Glycine max L. Wayne) was shown to be dependent on calcium but not calmodulin. The concentrations of free calcium required for half-maximal histone H1 phosphorylation and autophosphorylation were similar (≥ 2 micromolar). The protein kinase activity was stimulated 100-fold by ≥ 10 micromolar-free calcium. When exogenous soybean or bovine brain calmodulin was added in high concentration (1 micromolar) to the purified kinase, calcium-dependent and -independent activities were weakly stimulated (≤ 2-fold). Bovine serum albumin had a similar effect on both activities. The kinase was separated from a small amount of contaminating calmodulin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. After renaturation the protein kinase autophosphorylated and phosphorylated histone H1 in a calcium-dependent manner. Following electroblotting onto nitrocellulose, the kinase bound 45 Ca 2+ in the presence of KCl and MgCl 2 , which indicated that the kinase itself is a high-affinity calcium-binding protein. Also, the mobility of one of two kinase bands in SDS gels was dependent on the presence of calcium. Autophosphorylation of the calmodulin-free kinase was inhibited by the calmodulin-binding compound N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7), showing that the inhibition of activity by W-7 is independent of calmodulin. These results show that soybean calcium-dependent protein kinase represents a new class of protein kinase which requires calcium but not calmodulin for activity

50 CFR 648.54 - State waters exemption.

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2010-10-01

... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false State waters exemption. 648.54 Section 648... Atlantic Sea Scallop Fishery § 648.54 State waters exemption. (a) State eligibility for exemption. (1) A state may be eligible for a state waters exemption if it has a scallop fishery and a scallop...

40 CFR 279.54 - Used oil management.

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2010-07-01

... the requirements of this subpart. (a) Management units. Used oil processors/re-refiners may not store... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Used oil management. 279.54 Section...) STANDARDS FOR THE MANAGEMENT OF USED OIL Standards for Used Oil Processors and Re-Refiners § 279.54 Used oil...

9 CFR 54.10 - Tests for scrapie.

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2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Tests for scrapie. 54.10 Section 54.10... tests may be approved for the identification of suspect animals, for the identification of scrapie-positive animals, or for other purposes such as flock certification. For a test to be approved for the...

Control of nuclear-cytoplasmic shuttling of Ankrd54 by PKCδ

Institute of Scientific and Technical Information of China (English)

Amy L Samuels; Alison Louw; Reza Zareie; Evan Ingley

2017-01-01

AIM To identify and characterize the effect of phosphorylation on the subcellular localization of Ankrd54.METHODS HEK293 T cells were treated with calyculin A, staurosporin or phorbol 12-myristate 13-acetate(PMA). Cells were transfected with eG FP-tagged Ankrd54 with or without Lyn tyrosine kinase(wild-type, Y397 F mutant, or Y508 F mutant). The subcellular localization was assessed by immunofluorescence imaging of cells, immunoblotting of subcellular fractionations. The phosphorylation of Ankrd54 was monitored using Phos-tagT M gel retardation. Phosphorylated peptides were analysed by multiplereaction-monitoring(MRM) proteomic analysis.RESULTS Activation of PKC kinases using PMA promoted nuclear export of Ankrd54 and correlated with increased Ankrd54 phosphorylation, assayed using Phos-tag TM gel retardation. Co-expression of an active form of the PKCδisoform specifically promoted both phosphorylation and cytoplasmic localization of Ankrd54, while PKCδ, Akt and PKA did not. Alanine mutation of several serine residues in the amino-terminal region of Ankrd54(Ser14, Ser17, Ser18, Ser19) reduced both PMA induced cytoplasmic localization and phosphorylation of Ankrd54. Using MRM proteomic analysis, phosphorylation of the Ser18 residue of Ankrd54 was readily detectable in response to PMA stimulation. PMA stimulation of cells co-expressing Ankrd54 and Lyn tyrosine kinase displayed increased coimmunoprecipitation and enhanced co-localization in the cytoplasm.CONCLUSION We identify phosphorylation by PKCδ as a major regulator of nuclear-cytoplasmic shuttling of Ankrd54, and its interaction with the tyrosine kinase Lyn.

Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation.

Science.gov (United States)

Afdhal, N H; Ostrow, J D; Koehler, R; Niu, N; Groen, A K; Veis, A; Nunes, D P; Offner, G D

1995-11-01

Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4 precipitation were studied. Binding of CBP to GBM was assessed by inhibition of the fluorescence of the complex of GBM with bis-1,8-anilinonaphthalene sulfonic acid (bis-ANS). The effects of the proteins on precipitation of CaHPO4 were assessed by nephelometry and gravimetry. Precipitates were analyzed for calcium, phosphate, and protein. CBP and bis-ANS competitively displaced each other from 30 binding sites on mucin, with a 1:1 stoichiometry and similar affinity. The rate of precipitation of CaHPO4 was retarded by mucin and CBP. Precipitate mass was unaffected by GBM alone but decreased with the addition of CBP. Complexing CBP with GBM abolished or moderated this latter effect, altered precipitate morphology, and changed the stoichiometric ratios of Ca to PO4 in the precipitates from 1:1 to 3:2. Mucin and CBP were incorporated into the precipitates. These studies suggest that the formation of calcium-containing gallstones is a biomineralization process regulated by both GBM and CBP.

Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status

Science.gov (United States)

Dauer, Jenny M.; Perakis, Steven S.

2014-01-01

Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

Mortar and concrete based on calcium sulphate binders

NARCIS (Netherlands)

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

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

46 CFR 54.01-35 - Corrosion (modifies UG- 25).

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Corrosion (modifies UG- 25). 54.01-35 Section 54.01-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS General Requirements § 54.01-35 Corrosion (modifies UG- 25). (a) Vessels or portions of vessels subject to...

Effect of lactose on intestinal absorption of calcium; Effet du lactose sur l'absorption intestinale du calcium

Energy Technology Data Exchange (ETDEWEB)

Labat, Marie-Louise

1972-06-15

Calcium absorption was immediately increased when lactose was administered in large amounts in the intestine of standard rats fed on a vitamin D diet. The same effect could be reproduced with lactulose, a glucid un-hydrolyzed by lactase and unabsorbed. The occurrence of a saturation process for high doses of calcium agrees with a biochemical process through a carrier; this process was not inhibited by actinomycin D, which does not agree with a 'de novo' synthesis of a calcium binding protein; yet activation of the preexisting protein cannot be excluded. The intestinal effect of lactose resulted in an inhibition of bone catabolism in the adult normocalcemic rat indicating a possible interference of thyrocalcitonin. Finally in the young rat, hypocalcemic by lack of vitamin D, on account of the lactose effect, calcium can be considered as a 'third messenger' in the chain of intracellular events between the interaction of the parathyroid hormone with the bone receptor and the expression of its activity. (author) [French] Le lactose introduit en quantite importante dans l'intestin augmente immediatement l'absorption du calcium chez le rat normal recevant par ailleurs de la vitamine D. Cet effet peut etre reproduit par le lactulose, glucide non hydrolyse par la lactase et non absorbe. L'apparition d'un phenomene de saturation pour les doses elevees de calcium s'accorde avec un mecanisme biochimique mettant en jeu un transporteur. Ce mecanisme n'est pas inhibe par l'actinomycine D, ce qui ne s'accorde pas avec une synthese 'de novo' de proteine transporteuse liant le calcium; on ne peut toutefois exclure une activation de cette proteine preexistante. L'effet intestinal du lactose a pour consequence l'inhibition du catabolisme osseux chez le rat adulte normocalcemique; ceci pose le probleme d'une intervention eventuelle de la thyrocalcitonine. Enfin, l'effet lactose nous permet d'attribuer au calcium le role de 'troisieme messager' dans la chaine d

Sensory analysis of calcium-biofortified lettuce

Science.gov (United States)

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 l...

Phagocytosis-induced /sup 45/calcium efflux in polymorphonuclear leucocytes

Energy Technology Data Exchange (ETDEWEB)

Barthelemy, A; Schell-Frederick, E [Brussels Univ. (Belgium). Institut de Recherche Interdisciplinaire; Paridaens, R [Brussels Univ. (Belgium). Faculte de Medicine

1977-10-15

The role of calcium ions in regulating the structure and function of non-muscle cells is a subject of intense study. Several lines of evidence that calcium may be essential in the function of polymorphonuclear leuocytes (PMNL) and an important control element in the process of phagocytosis. Direct studies of calcium distribution and fluxes have only recently been undertaken. To our knowledge, no report of calcium movements during normal phagocytosis has been published. In the context of an overall study of calcium dynamics in the PMNL, we report here initial studies on /sup 45/Ca efflux in prelabelled guinea pig PMNL. The results demonstrate the energy-dependence of resting calcium efflux and an increased efflux upon addition of phagocytic particles which is not dependent on particle internalization.

Angiotensin effects on calcium and steroidogenesis in adrenal glomerulosa cells

International Nuclear Information System (INIS)

Elliott, M.E.; Siegel, F.L.; Hadjokas, N.E.; Goodfriend, T.L.

1985-01-01

We investigated the role of cellular calcium pools in angiotensin II-stimulated aldosterone synthesis in bovine adrenal glomerulosa cells. Angiotensin II decreased the size of the exchangeable cell calcium pool by 34%, consistent with previous observations that angiotensin II causes decreased uptake of 45 Ca+2 into cells and increased efflux of 45 Ca+2 from preloaded cells. Atomic absorption spectroscopy showed that angiotension II caused a decrease of 21% in total cellular calcium. Angiotensin II caused efflux of 45 Ca+2 in the presence of EGTA and retarded uptake of 45 Ca+2 when choline was substituted for sodium, suggesting that hormone effects on calcium pools do not involve influx of trigger calcium or sodium. Cells incubated in calcium-free buffer and 0.1 mM or 0.5 mM EGTA synthesized reduced (but still significant) amounts of the steroid in response to hormone. Cells incubated in increasing concentrations of extracellular calcium contained increasing amounts of intracellular calcium and synthesized increasing amounts of aldosterone in response to angiotensin II. These results point to the participation of intracellular calcium pools in angiotensin II-stimulated steroidogenesis and the importance of extracellular calcium in maintaining these pools

The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

Directory of Open Access Journals (Sweden)

Yajin Liao

2017-02-01

Full Text Available The mitochondrial calcium uniporter (MCU—a calcium uniporter on the inner membrane of mitochondria—controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP; however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.

Activation of L-type calcium channels is required for gap junction-mediated intercellular calcium signaling in osteoblastic cells

DEFF Research Database (Denmark)

Jørgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne

2003-01-01

The propagation of mechanically induced intercellular calcium waves (ICW) among osteoblastic cells occurs both by activation of P2Y (purinergic) receptors by extracellular nucleotides, resulting in "fast" ICW, and by gap junctional communication in cells that express connexin43 (Cx43), resulting...... in "slow" ICW. Human osteoblastic cells transmit intercellular calcium signals by both of these mechanisms. In the current studies we have examined the mechanism of slow gap junction-dependent ICW in osteoblastic cells. In ROS rat osteoblastic cells, gap junction-dependent ICW were inhibited by removal...... of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx...

Tyrosine Residues Regulate Multiple Nuclear Functions of P54nrb.

Science.gov (United States)

Lee, Ahn R; Hung, Wayne; Xie, Ning; Liu, Liangliang; He, Leye; Dong, Xuesen

2017-04-01

The non-POU-domain-containing octamer binding protein (NONO; also known as p54nrb) has various nuclear functions ranging from transcription, RNA splicing, DNA synthesis and repair. Although tyrosine phosphorylation has been proposed to account for the multi-functional properties of p54nrb, direct evidence on p54nrb as a phosphotyrosine protein remains unclear. To investigate the tyrosine phosphorylation status of p54nrb, we performed site-directed mutagenesis on the five tyrosine residues of p54nrb, replacing the tyrosine residues with phenylalanine or alanine, and immunoblotted for tyrosine phosphorylation. We then preceded with luciferase reporter assays, RNA splicing minigene assays, co-immunoprecipitation, and confocal microscopy to study the function of p54nrb tyrosine residues on transcription, RNA splicing, protein-protein interaction, and cellular localization. We found that p54nrb was not phosphorylated at tyrosine residues. Rather, it has non-specific binding affinity to anti-phosphotyrosine antibodies. However, replacement of tyrosine with phenylalanine altered p54nrb activities in transcription co-repression and RNA splicing in gene context-dependent fashions by means of differential regulation of p54nrb protein association with its interacting partners and co-regulators of transcription and splicing. These results demonstrate that tyrosine residues, regardless of phosphorylation status, are important for p54nrb function. J. Cell. Physiol. 232: 852-861, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

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.

Calcium Channel Blockers

Science.gov (United States)

... Certain calcium channel blockers interact with grapefruit products. Kaplan NM, et al. Treatment of hypertension: Drug therapy. In: Kaplan's Clinical Hypertension. 11th ed. Philadelphia, Pa.: Wolters Kluwer ...

10 CFR 430.54 - Referral to the Attorney General.

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Referral to the Attorney General. 430.54 Section 430.54... Business Exemptions § 430.54 Referral to the Attorney General. Notice of the application for exemption under this subpart shall be transmitted to the Attorney General by the Secretary and shall contain (a) a...

The Relation between Calcium Supplement Consumption and Calcific Shoulder Tendonitis

Directory of Open Access Journals (Sweden)

Alireza Rouhani

2015-10-01

Full Text Available Background: Calcific tendonitis is a common cause of non-traumatic shoulder pain. Previous studies have suggested a relation between minerals and endocrine and calcium deposition. Thus, hypercalcemia is probably related to calcific tendonitis. This study aims at evaluating the relation found between calcium supplement consumption and calcific shoulder tendonitis. Methods: This analytical-descriptive study was conducted on 250 patients with shoulder pain referring to clinics and emergency department of Shohada Orthopedics Hospital during one year for considering calcific shoulder tendonitis and calcium supplement consumption. Patients with calcific tendonitis were treated and their functional ability was evaluated using DASH questionnaire, pain severity and range of motion (ROM before and after treatment and their correlation with calcium supplement consumption. Results: Calcific tendonitis and calcium consumption were generally seen in 30 (12% and 73 (29.2% cases, respectively. Calcium consumption frequency in patients with calcific tendonitis was significantly higher than the patients who did not consume calcium supplements (76.7% vs. 22.7%. Patients with calcific tendonitis who did not consume calcium supplements suffered from significantly longer periods of shoulder pain. All patients having consumed calcium supplement were female. The group who consumed calcium supplement had significantly severe pain and higher DASH score before and after treatment, while there was no significant difference in number of impaired ROM before and after treatment. Also, there was a negative correlation between calcium supplement consumption, pain severity and DASH score before and after treatment. Conclusion: Calcium supplement consumption is related to calcific tendonitis and is also accompanied with more pain and lower functional ability in patients with calcific tendonitis.    Keywords: Calcific tendonitis; Shoulder; Calcium supplement; Pain

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

Enhanced expression of a calcium-dependent protein kinase

Indian Academy of Sciences (India)

Among the downstream targets of calcium in plants, calcium-dependent protein kinases (CDPKs) form an interesting class of kinases which are activated by calcium binding. They have been implicated in a diverse array of responses to hormonal and environmental stimuli. In order to dissect the role of CDPKs in the moss ...

Research of pharmacokinetics of L-threonate calcium with 45Ca radiotrace

International Nuclear Information System (INIS)

Tong Jian; Niu Huisheng; Li Huaifen

2001-01-01

The pharmacokinetics of calcium in L-threonate calcium is studied by radiotrace method. The results show the relationship between drug-time curve, pharmacokinetics parameters and dosage are positive correlation, and calcium distributes in important tissues such as stomach, intestines, blood and bone. In 24 hours, about 40% calcium is drained in urine, 30% calcium is evacuated in feces, 10%-20% calcium deposit in blood or bone. The radiotrace method is a kind of special, sensitive, accurate method of testing calcium metabolism

Measurements of the Fe-54 (n,p) Mn-54 Reaction Cross Section in the Neutron Energy Range 2.3-3.8 MeV

International Nuclear Information System (INIS)

Lauber, A.; Malmskog, S.

1964-10-01

We have measured the 54 Fe (n, p) 54 Mn reaction cross section using a surface barrier detector to record the number of protons released in the reaction. The neutron flux was determined by means of a hydrogenous radiator, detecting the scattered protons with the solid state detector, and calculating the number of impinging neutrons from the well known n-p scattering cross section. The 54 Fe (n, p) 54 Mn reaction cross section is found to increase from 25 mb at 2.3 MeV to 208 mb at 3.5 MeV

Obtainment of calcium carbonate from mussels shell

International Nuclear Information System (INIS)

Hamester, M.R.R.; Becker, D.

2010-01-01

The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

Calcium and Vitamin D Supplementation in Men

Directory of Open Access Journals (Sweden)