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Sample records for calcium 41 target

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

    Science.gov (United States)

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

    2012-05-15

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

  2. Regulation of gamma T-cell antigen receptor expression by intracellular calcium in acute lymphoblastic leukemia cell line DND41.

    Science.gov (United States)

    Peralta-Zaragoza, O; Martínez-Valdez, H; Madrid-Marina, V

    1996-01-01

    The calcium ionophore, ionomycin, promotes an increase of intracellular calcium and regulates mRNA expression of gamma/delta-TcR gene in human T lymphocytes. The mechanism of this regulation is not yet clear. Thus, the regulation by intracellular calcium requires elucidation. We studied the gamma-TcR gene expression in acute lymphoblastic leukemia cell line DND41 (CD4- CD8-) by Northern blot and flow cytometric analysis. The mRNA levels of gamma-TcR increased by ionomycin, anti-CD3, and with TPA. TPA had an antagonistic effect to both ionomycin and anti-CD3. Also, TPA inhibits the increased intracellular calcium promoted by ionomycin but not the increase promoted by anti-CD3 and ionomycin. Our results suggest that intracellular calcium induces mRNA and protein expression of gamma-TcR chain. This effect is antagonized by protein kinase C-activation. Thus, we conclude that the target cells of the differential regulation on gamma-TcR mRNA expression by intracellular calcium modulators are the CD4- CD8- cells, and this is due to cytosolic calcium mobilization. PMID:8854386

  3. Tannin inhibits HIV-1 entry by targeting gp41

    Institute of Scientific and Technical Information of China (English)

    Lin L(U); Shu-wen LIU; Shi-bo JIANG; Shu-guang WU

    2004-01-01

    AIM: To investigate the mechanism by which tannin inhibits HIV-1 entry into target cells. METHODS: The inhibitory activity of tannin on HIV-1 replication and entry was detected by p24 production and HIV-1-mediated cell fusion, respectively. The inhibitory activity on the gp41 six-helix bundle formation was determined by an improved sandwich ELISA. RESULTS: Tannins from different sources showed potent inhibitory activity on HIV-1 replication,HIV-1-mediated cell fusion, and the gp4 six-helix bundle formation. CONCLUSION: Tannin inhibits HIV-1 entry into target cells by interfering with the gp41 six-helix bundle formation, thus blocking HIV-1 fusion with the target cell.

  4. Human calcium metabolism including bone resorption measured with {sup 41}Ca tracer

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, S.P.H.T. [Lawrence Livermore National Lab., CA (United States); King, J.C. [California Univ., Berkeley, CA (United States). Dept. of Nutritional Science; Vieira, N.E. [National Inst. of Child Health and Human Development, Bethesda, MD (United States); Woodhouse, L.R. [California Univ., Berkeley, CA (United States). Dept. of Nutritional Science; Yergey, A.L. [National Inst. of Child Health and Human Development, Bethesda, MD (United States)

    1996-08-01

    Accelerator mass spectrometry is so sensitive to small quantities of {sup 41}Ca that it might be used as a tracer in the study of human calcium kinetics to generate unique kinds of data. In contrast with the use of other Ca isotopic tracers, {sup 41}Ca tracer can be so administered that the tracer movements between the various body pools achieve a quasi steady state. Resorbing bone may thus be directly measured. We have tested such a protocol against a conventional stable isotope experiment with good agreement.

  5. Molecular Structure and Target Recognition of Neuronal Calcium Sensor Proteins

    Directory of Open Access Journals (Sweden)

    James Ames

    2012-02-01

    Full Text Available Neuronal calcium sensor (NCS proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite distinct. Retinal recoverin and guanylate cyclase activating proteins (GCAPs both serve as calcium sensors in retinal rod cells, neuronal frequenin (NCS1 modulates synaptic activity and neuronal secretion, K+ channel interacting proteins (KChIPs regulate ion channels to control neuronal excitability, and DREAM (KChIP3 is a transcriptional repressor that regulates neuronal gene expression. Here we review the molecular structures of myristoylated forms of NCS1, recoverin, and GCAP1 that all look very different, suggesting that the sequestered myristoyl group helps to refold these highly homologous proteins into very different structures. The molecular structure of NCS target complexes have been solved for recoverin bound to rhodopsin kinase, NCS-1 bound to phosphatidylinositol 4-kinase, and KChIP1 bound to A-type K+ channels. We propose that N-terminal myristoylation is critical for shaping each NCS family member into a different structure, which upon Ca2+-induced extrusion of the myristoyl group exposes a unique set of previously masked residues that interact with a particular physiological target.

  6. Computer-Aided Approaches for Targeting HIVgp41

    Directory of Open Access Journals (Sweden)

    William J. Allen

    2012-08-01

    Full Text Available Virus-cell fusion is the primary means by which the human immunodeficiency virus-1 (HIV delivers its genetic material into the human T-cell host. Fusion is mediated in large part by the viral glycoprotein 41 (gp41 which advances through four distinct conformational states: (i native, (ii pre-hairpin intermediate, (iii fusion active (fusogenic, and (iv post-fusion. The pre-hairpin intermediate is a particularly attractive step for therapeutic intervention given that gp41 N-terminal heptad repeat (NHR and C‑terminal heptad repeat (CHR domains are transiently exposed prior to the formation of a six-helix bundle required for fusion. Most peptide-based inhibitors, including the FDA‑approved drug T20, target the intermediate and there are significant efforts to develop small molecule alternatives. Here, we review current approaches to studying interactions of inhibitors with gp41 with an emphasis on atomic-level computer modeling methods including molecular dynamics, free energy analysis, and docking. Atomistic modeling yields a unique level of structural and energetic detail, complementary to experimental approaches, which will be important for the design of improved next generation anti-HIV drugs.

  7. Molecular Structure and Target Recognition of Neuronal Calcium Sensor Proteins

    OpenAIRE

    James Ames; Mitsuhiko Ikura

    2011-01-01

    Neuronal calcium sensor (NCS) proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite distinct. Retinal recoverin and guanylate cyclase activating proteins (GCAPs) both serve as calcium sensors in retinal rod cells, neuronal frequenin (NCS1) modulates synaptic acti...

  8. Molecular structure and target recognition of neuronal calcium sensor proteins

    OpenAIRE

    Ames, James B.; Lim, Sunghyuk; Ikura, Mitsuhiko

    2012-01-01

    Neuronal calcium sensor (NCS) proteins, a sub-branch of the EF-hand superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite distinct. Retinal recoverin and guanylate cyclase activating proteins (GCAPs) both serve as calcium sensors in retinal rod cells, neuronal frequenin (NCS1) modulates synaptic activit...

  9. Targeted cellular ionic calcium chelation by oxalates: Implications for the treatment of tumor cells

    Directory of Open Access Journals (Sweden)

    Embi Abraham

    2012-12-01

    , and extracellular calcium chelation stores of the Astrocytes (which has been shown to slow neural conduction. Implications of the Hypothesis The life expectancy in patients with metastasized malignant melanoma brain tumors could be significantly prolonged if the chemotherapeutic issue of brain metastasis is overcome. Other cancerous tumors can also be treated by this Targeted Chelation Approach. Ionic calcium sequestration using naturally occurring calcium chelators, viz., oxalates, could accomplish this desired outcome.

  10. 44gSc from metal calcium targets for PET

    DEFF Research Database (Denmark)

    Severin, Gregory; Gagnon, K.; Engle, J. W.;

    2012-01-01

    A low-cost and efficient method for producing pre-clinical scale quantities of 44gSc is presented. Production involves proton irradiation of natural unenriched calcium metal followed by rapid separation of radioscandium from the target using hydroxmate functionalized resin.© 2012 American Institu...

  11. Subcellular targeting of nine calcium-dependent protein kinase isoforms from Arabidopsis

    Science.gov (United States)

    Dammann, Christian; Ichida, Audrey; Hong, Bimei; Romanowsky, Shawn M.; Hrabak, Estelle M.; Harmon, Alice C.; Pickard, Barbara G.; Harper, Jeffrey F.; Evans, M. L. (Principal Investigator)

    2003-01-01

    Calcium-dependent protein kinases (CDPKs) are specific to plants and some protists. Their activation by calcium makes them important switches for the transduction of intracellular calcium signals. Here, we identify the subcellular targeting potentials for nine CDPK isoforms from Arabidopsis, as determined by expression of green fluorescent protein (GFP) fusions in transgenic plants. Subcellular locations were determined by fluorescence microscopy in cells near the root tip. Isoforms AtCPK3-GFP and AtCPK4-GFP showed a nuclear and cytosolic distribution similar to that of free GFP. Membrane fractionation experiments confirmed that these isoforms were primarily soluble. A membrane association was observed for AtCPKs 1, 7, 8, 9, 16, 21, and 28, based on imaging and membrane fractionation experiments. This correlates with the presence of potential N-terminal acylation sites, consistent with acylation as an important factor in membrane association. All but one of the membrane-associated isoforms targeted exclusively to the plasma membrane. The exception was AtCPK1-GFP, which targeted to peroxisomes, as determined by covisualization with a peroxisome marker. Peroxisome targeting of AtCPK1-GFP was disrupted by a deletion of two potential N-terminal acylation sites. The observation of a peroxisome-located CDPK suggests a mechanism for calcium regulation of peroxisomal functions involved in oxidative stress and lipid metabolism.

  12. Manufacturing of calcium, lithium and molybdenum targets for use in nuclear physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kheswa, N.Y., E-mail: kheswa@tlabs.ac.z [iThemba Laboratory for Accelerator Based Science, P.O. Box 722, Somerset West 7129, Western Cape (South Africa); Papka, P.; Buthelezi, E.Z.; Lieder, R.M.; Neveling, R.; Newman, R.T. [iThemba Laboratory for Accelerator Based Science, P.O. Box 722, Somerset West 7129, Western Cape (South Africa)

    2010-02-11

    This paper describes methods used in the manufacturing of chemically reactive targets such as calcium ({sup nat}Ca), lithium-6 ({sup 6}Li) and molybdenum-97 ({sup 97}Mo) for nuclear physics experiments at the iThemba LABS cyclotron facility (Faure, South Africa). Due to the chemical properties of these materials a suitable and controlled environment was established in order to minimize oxygen contamination of targets. Calcium was prepared by means of vacuum evaporation while lithium was cold rolled to a desired thickness. In the case of molybdenum, the metallic powder was melted under vacuum using an e-gun followed by cold rolling of the metal bead to a desired thickness. In addition, latest developments toward the establishment of a dedicated nuclear physics target laboratory are discussed.

  13. Labeling the human skeleton with 41Ca to assess changes in bone calcium metabolism

    International Nuclear Information System (INIS)

    Bone research is limited by the methods available for detecting changes in bone metabolism. While dual X-ray absorptiometry is rather insensitive, biochemical markers are subject to significant intra-individual variation. In the study presented here, we evaluated the isotopic labeling of bone using 41Ca, a long-lived radiotracer, as an alternative approach. After successful labeling of the skeleton, changes in the systematics of urinary 41Ca excretion are expected to directly reflect changes in bone Ca metabolism. A minute amount of 41Ca (100 nCi) was administered orally to 22 postmenopausal women. Kinetics of tracer excretion were assessed by monitoring changes in urinary 41Ca/40Ca isotope ratios up to 700 days post-dosing using accelerator mass spectrometry and resonance ionization mass spectrometry. Isotopic labeling of the skeleton was evaluated by two different approaches: (i) urinary 41Ca data were fitted to an established function consisting of an exponential term and a power law term for each individual; (ii) 41Ca data were analyzed by population pharmacokinetic (NONMEM) analysis to identify a compartmental model that describes urinary 41Ca tracer kinetics. A linear three-compartment model with a central compartment and two sequential peripheral compartments was found to best fit the 41Ca data. Fits based on the use of the combined exponential/power law function describing urinary tracer excretion showed substantially higher deviations between predicted and measured values than fits based on the compartmental modeling approach. By establishing the urinary 41Ca excretion pattern using data points up to day 500 and extrapolating these curves up to day 700, it was found that the calculated 41Ca/40Ca isotope ratios in urine were significantly lower than the observed 41Ca/40Ca isotope ratios for both techniques. Compartmental analysis can overcome this limitation. By identifying relative changes in transfer rates between compartments in response to an

  14. Approaches for Identification of HIV-1 Entry Inhibitors Targeting gp41 Pocket

    OpenAIRE

    Debnath, Asim K.; Shibo Jiang; Xiaojie Zhu; Lanying Du; Fei Yu; Lu Lu

    2013-01-01

    The hydrophobic pocket in the HIV-1 gp41 N-terminal heptad repeat (NHR) domain plays an important role in viral fusion and entry into the host cell, and serves as an attractive target for development of HIV-1 fusion/entry inhibitors. The peptide anti-HIV drug targeting gp41 NHR, T-20 (generic name: enfuvirtide; brand name: Fuzeon), was approved by the U.S. FDA in 2003 as the first HIV fusion/entry inhibitor for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral d...

  15. Large-scale calcium metal sample preparation for 41Ca isotope enrichment

    International Nuclear Information System (INIS)

    Experiments are underway at Argonne National Laboratory to measure the 41Ca radioisotope concentration (T1/2 = 100 000 years) in natural samples of terrestrial origin by accelerator mass spectrometry (AMS). Since the concentration of 41Ca in these samples is expected to be very low, enrichment with a Calutron Isotope Separator at Oak Ridge National Laboratory is being used. This separator requires rather large quantities of high-purity Ca metal (typically 100 g/loading) as source material. Details of the methods of obtaining these metallic samples from various materials will be presented. (orig.)

  16. Approaches for Identification of HIV-1 Entry Inhibitors Targeting gp41 Pocket

    Directory of Open Access Journals (Sweden)

    Asim K. Debnath

    2013-01-01

    Full Text Available The hydrophobic pocket in the HIV-1 gp41 N-terminal heptad repeat (NHR domain plays an important role in viral fusion and entry into the host cell, and serves as an attractive target for development of HIV-1 fusion/entry inhibitors. The peptide anti-HIV drug targeting gp41 NHR, T-20 (generic name: enfuvirtide; brand name: Fuzeon, was approved by the U.S. FDA in 2003 as the first HIV fusion/entry inhibitor for treatment of HIV/AIDS patients who fail to respond to the current antiretroviral drugs. However, because T20 lacks the pocket-binding domain (PBD, it exhibits low anti-HIV-1 activity and short half-life. Therefore, several next-generation HIV fusion inhibitory peptides with PBD have been developed. They possess longer half-life and more potent antiviral activity against a broad spectrum of HIV-1 strains, including the T-20-resistant variants. Nonetheless, the clinical application of these peptides is still limited by the lack of oral availability and the high cost of production. Thus, development of small molecule compounds targeting the gp41 pocket with oral availability has been promoted. This review describes the main approaches for identification of HIV fusion/entry inhibitors targeting the gp41 pocket and summarizes the latest progress in developing these inhibitors as a new class of anti-HIV drugs.

  17. Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

    Energy Technology Data Exchange (ETDEWEB)

    Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

    2012-06-15

    Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

  18. Study on Different Forms of Calcium Metabolic Behavior in Normal and Osteoporosis Rats by ~(41)Ca Tracing

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Because of calcium deficiency,there were about 90 million Chinese people suffering from osteoporosis which caused a great calcium supplement boom in 2009. However, recent studies have shown that excess calcium supplement may cause some other diseases

  19. Assessing potential targets of calcium action in light-modulated gravitropism

    Science.gov (United States)

    Roux, S. J.

    1995-01-01

    Light, through the mediation of the pigment phytochrome, modulates the gravitropic response of the shoots and roots of many plants. The transduction of both light and gravity stimuli appears to involve Ca(2+)-regulated steps, one or more of which may represent points of intersection between the two transduction chains. To be confident that Ca2+ plays a critical role in stimulus-response coupling for gravitropism, it will be important to identify specific targets of Ca2+ action whose function can be clearly linked to the regulation of growth. Calcium typically exerts its influence on cell metabolism through binding to and activating key regulatory proteins. The three best characterized of these proteins in plants are the calmodulins, calcium-dependent protein kinases, and annexins. In this review we summarize what is known about the structure and function of these proteins and speculate on how their activation by Ca2+ could influence the differential growth response of gravitropism.

  20. Neutron induced reactions on aluminum-26, chloride-36 and calcium-41 and their astrophysical implications

    Science.gov (United States)

    de Smet, Liesbeth Paula

    In this work (n,p) and (n,a) reactions on 26 A1, 36 Cl and 41 Ca are studied as a function of the neutron energy. The measurements were performed at the high resolution GELINA time-of-flight facility of the IRMM in Geel, Belgium. Besides the nuclear physics information obtained from the resonance analysis of the reaction cross sections, these reactions are of importance in the understanding of the observed 36 S and 26 Al solar abundances. In the case of 26 Al, the 26 A1(n,a) 23 Na cross section up to 45 keV has been determined. Six resonances are observed. For three of them, the total level width and the spin could be calculated. For most of the resonances the obtained resonance parameters are in agreement with previous data. The calculated Maxwellian Averaged Cross Section values (MACS) used in stellar model calculations confirm that 26 Al is indeed severely depleted by neutron captures in AGB stars. In the (n,p) and (n,a) measurements on 36 Cl, eighteen resonances are observed in the energy region up to 250 keV, whereas eight were identified before. Only the lowest energy resonance shows a significant (n,(x)-contribution of (76±7)%, which is in perfect agreement with the value reported before. Furthermore, for four resonances, the resonance strength, spin, total and partial width G p could be determined. They are in good agreement with previous data, but the achieved accuracy is better. The calculated MACS values are used in stellar model calculations to trace the origin of 36 S and reveal that the weak component of the s-process occurring in massive stars accounts for almost the entire production of solar 36 S. The 41 Ca(n,a) 3 8Ar measurement is the first ever reported in the resonance region and affects the 36 S abundance through 41 Ca(n,a) 38 Ar(n,g) 39 Ar(n,a) 36 S. Twelve resonances are observed in the energy region up to 45 keV. For most of them the area, the total width, the spin and a value for G n /G p could be determined. After extension of the energy

  1. Calcium-sensing receptor: A new target for therapy of diarrhea.

    Science.gov (United States)

    Cheng, Sam Xianjun

    2016-03-01

    Management of acute diarrhea remains a global challenge, particularly in resource-limiting countries. Oral rehydration solution (ORS), a passive rehydrating therapy developed approximately 40 years ago, remains the mainstay treatment. Although ORS is effective for hydration, since it does not inhibit enterotoxin-mediated excessive secretion, reduced absorption and compromised barrier function - the primary mechanisms of diarrhea, ORS does not offer a rapid relief of diarrhea symptom. There are a few alternative therapies available, yet the use of these drugs is limited by their expense, lack of availability and/or safety concerns. Novel anti-diarrheal therapeutic approaches, particularly those simple affordable therapies, are needed. This article explores intestinal calcium-sensing receptor (CaSR), a newly uncovered target for therapy of diarrhea. Unlike others, targeting this host antidiarrheal receptor system appears "all-inclusive": it is anti-secretory, pro-absorptive, anti-motility, and anti-inflammatory. Thus, activating CaSR reverses changes of both secretory and inflammatory diarrheas. Considering its unique property of using simple nutrients such as calcium, polyamines, and certain amino acids/oligopeptides as activators, it is possible that through targeting of CaSR with a combination of specific nutrients, novel oral rehydrating solutions that are inexpensive and practical to use in all countries may be developed. PMID:26973410

  2. Why Basic Calcium Phosphate Crystals Should Be Targeted In the Treatment of Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Claire-Louise Murphy

    2014-07-01

    Full Text Available Osteoarthritis (OA is the most common form of arthritis and results in significant social, psychological, and economic costs. It is characterised by progressive cartilage loss, bone remodelling, osteophyte formation, and synovial inflammation with resultant joint pain and disability. Since OA affects the entire joint, it is not surprising that there has been difficulty developing an effective targeted treatment. Treatments available for structural disease modification are limited. Current options appear to mostly reduce symptoms. Basic calcium phosphate (BCP crystals represent a potential therapeutic target in OA; they have been found in 100% of knee and hip cartilages removed at joint replacement. Intra-articular BCP crystals are associated with large joint effusions and dissolution of intra-articular structures, synovial proliferation, and marked degeneration as assessed by diagnostic imaging. While BCP deposition has been considered by many to be simply a consequence of advanced OA, there is substantial evidence to support BCP crystal deposition as an active pathogenic mediator of OA. BCP crystals exhibit a multiplicity of biologic effects in vitro including the ability to stimulate mitogenesis and prostaglandin, cytokine, and matrix metalloproteinase (MMP synthesis in a number of cell types including macrophages, synovial fibroblasts, and chondrocytes. BCP crystals also contribute to inflammation in OA through direct interaction with the innate immune system. Intra-articular BCP crystals can elicit synovial inflammation and cartilage degradation in mice in vivo . Although intra-articular BCP crystals are difficult to detect at the bedside, advances in modern technology should allow improved identification and quantitation of BCP crystals. Our article focuses on why basic calcium crystals are important in the pathogenesis of OA. There is ample evidence that BCP crystals should be explored as a therapeutic target in OA.

  3. Comparison of the calcium release channel of cardiac and skeletal muscle sarcoplasmic reticulum by target inactivation analysis

    International Nuclear Information System (INIS)

    The calcium release channel of sarcoplasmic reticulum which triggers muscle contraction in excitation-contraction coupling has recently been isolated. The channel has been found to be morphologically identical with the feet structures of the junctional face membrane of terminal cisternae and consists of an oligomer of a unique high molecular weight polypeptide. In this study, the authors compare the target size of the calcium release channel from heart and skeletal muscle using target inactivation analysis. The target molecular weights of the calcium release channel estimated by measuring ryanodine binding after irradiation are similar for heart (139,000) and skeletal muscle (143,000) and are smaller than the monomeric unit (estimated to be about 360,000). The target size, estimated by measuring polypeptide remaining after irradiation, was essentially the same for heart and skeletal muscle, 1,061,000 and 1,070,000, respectively, indicating an oligomeric association of protomers. Thus, the calcium release channel of both cardiac and skeletal muscle reacts uniquely with regard to target inactivation analysis in that (1) the size by ryanodine binding is smaller than the monomeric unit and (2) a single hit leads to destruction of more than one polypeptide, by measuring polypeptide remaining. The target inactivation analysis studies indicate that heart and skeletal muscle receptors are structurally very similar

  4. Peptide P5 (residues 628–683, comprising the entire membrane proximal region of HIV-1 gp41 and its calcium-binding site, is a potent inhibitor of HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Clavel François

    2008-10-01

    Full Text Available Abstract The membrane proximal region (MPR of the transmembrane subunit, gp41, of the HIV envelope glycoprotein plays a critical role in HIV-1 infection of CD4+ target cells and CD4-independent mucosal entry. It contains continuous epitopes recognized by neutralizing IgG antibodies 2F5, 4E10 and Z13, and is therefore considered to be a promising target for vaccine design. Moreover, some MPR-derived peptides, such as T20 (enfuvirtide, are in clinical use as HIV-1 inhibitors. We have shown that an extended MPR peptide, P5, harbouring the lectin-like domain of gp41 and a calcium-binding site, is implicated in the interaction of HIV with its mucosal receptor. We now investigate the potential antiviral activities of P5 and other such long MPR-derived peptides. Structural studies of gp41 MPR-derived peptides using circular dichroism showed that the peptides P5 (a.a.628–683, P1 (a.a.648–683, P5L (a.a.613–683 and P7 (a.a.613–746 displayed a well-defined α-helical structure. Peptides P5 inhibited HIV-1 envelope mediated cell-cell fusion and infection of peripheral blood mononuclear cells by both X4- and R5-tropic HIV-1 strains, whereas peptides P5 mutated in the calcium binding site or P1 lacked antiviral activity, when P5L blocked cell fusion in contrast to P7. Strikingly, P5 inhibited CD4-dependent infection by T20-resistant R5-tropic HIV-1 variants. Cell-cell fusion studies indicated that the anti-HIV-1 activity of P5, unlike T20, could not be abrogated in the presence of the N-terminal leucine zipper domain (LZ. These results suggested that P5 could serve as a potent fusion inhibitor.

  5. Calcium-activated potassium channels in insect pacemaker neurons as unexpected target site for the novel fumigant dimethyl disulfide.

    Science.gov (United States)

    Gautier, Hélène; Auger, Jacques; Legros, Christian; Lapied, Bruno

    2008-01-01

    Dimethyl disulfide (DMDS), a plant-derived insecticide, is a promising fumigant as a substitute for methyl bromide. To further understand the mode of action of DMDS, we examined its effect on cockroach octopaminergic neurosecretory cells, called dorsal unpaired median (DUM) neurons, using whole-cell patch-clamp technique, calcium imaging and antisense oligonucleotide strategy. At low concentration (1 microM), DMDS modified spontaneous regular spike discharge into clear bursting activity associated with a decrease of the amplitude of the afterhyperpolarization. This effect led us to suspect alterations of calcium-activated potassium currents (IKCa) and [Ca(2+)](i) changes. We showed that DMDS reduced amplitudes of both peak transient and sustained components of the total potassium current. IKCa was confirmed as a target of DMDS by using iberiotoxin, cadmium chloride, and pSlo antisense oligonucleotide. In addition, we showed that DMDS induced [Ca(2+)](i) rise in Fura-2-loaded DUM neurons. Using calcium-free solution, and (R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-[2-(2,3,4-trimethoxy-phenyl)ethyl]-acetamide (LOE 908) [an inhibitor of transient receptor potential (TRP)gamma], we demonstrated that TRPgamma initiated calcium influx. By contrast, omega-conotoxin GVIA (an inhibitor of N-type high-voltage-activated calcium channels), did not affect the DMDS-induced [Ca(2+)](i) rise. Finally, the participation of the calcium-induced calcium release mechanism was investigated using thapsigargin, caffeine, and ryanodine. Our study revealed that DMDS-induced elevation in [Ca(2+)](i) modulated IKCa in an unexpected bell-shaped manner via intracellular calcium. In conclusion, DMDS affects multiple targets, which could be an effective way to improve pest control efficacy of fumigation. PMID:17942746

  6. PDLIM7 is a novel target of the ubiquitin ligase Nedd4-1 in skeletal muscle.

    Science.gov (United States)

    D'Cruz, Robert; Plant, Pamela J; Pablo, Lesley A; Lin, Shouzhe; Chackowicz, Joshua; Correa, Judy; Bain, James; Batt, Jane

    2016-02-01

    Skeletal muscle atrophy remains a complication occurring both as a natural response to muscle disuse and as a pathophysiological response to illness such as diabetes mellitus and nerve injury, such as traumatic muscle denervation. The ubiquitin-proteasome system (UPS) is the predominant proteolytic machinery responsible for atrophy of skeletal muscle, and Nedd4-1 (neural precursor cell-expressed developmentally down-regulated 4-1) is one of a series of E3 ubiquitin ligases identified to mediate inactivity-induced muscle wasting. Targets of Nedd4-1 mediated ubiquitination in skeletal muscle remain poorly understood. In the present study, we identified PDLIM7 (PDZ and LIM domain 7, Enigma), a member of the PDZ-LIM family of proteins, as a novel target of Nedd4-1 in skeletal muscle. The PDZ-LIM family of proteins is known to regulate muscle development and function. We show that Nedd4-1 expression in muscle atrophied by denervation is co-incident with a decrease in PDLIM7 and that PDLIM7 protein levels are stabilized in denervated muscle of Nedd4-1 skeletal muscle-specific knockout mice (SMS-KO). Exogenous PDLIM7 and Nedd4-1 transfected into human embryonic kidney (HEK)293 cells co-immunoprecipitate through binding between the PY motif of PDLIM7 and the second and third WW domains of Nedd4-1 and endogenous PDLIM7 and Nedd4-1 interact in the cytoplasm of differentiated C2C12 myotubes, leading to PDLIM7 ubiquitination. These results identify PDLIM7 as a bona fide skeletal muscle substrate of Nedd4-1 and suggest that this interaction may underlie the progression of skeletal muscle atrophy. This offers a novel therapeutic target that could be potentially used to attenuate muscle atrophy. PMID:26556890

  7. Development of peptide and small-molecule HIV-1 fusion inhibitors that target gp41.

    Science.gov (United States)

    Cai, Lifeng; Jiang, Shibo

    2010-11-01

    It has been 25 years since the development of the first efficient HIV-1/AIDS treatment. Scientists now know more about the HIV-1 infection life cycle, and more than 30 antiretroviral drugs have been developed, including HIV-1 fusion inhibitors. Fundamental work was begun in the early 1990s and led to the development of a novel class of anti-HIV-1 drugs, culminating in a peptide known as T20, which is currently the only HIV-1 fusion inhibitor approved by the US Food and Drug Administration. However, more work needs to be done to perfect the development of peptide and small-molecule HIV fusion inhibitors, particularly those that target gp41. Herein we present a brief overview of the development of this class of anti-HIV-1 drug by focusing on the achievements, challenges, and lessons learned. We cite hallmark studies of the past and comment on future drug development. PMID:20845360

  8. Calcium/calmodulin-dependent protein kinase IV: A multifunctional enzyme and potential therapeutic target.

    Science.gov (United States)

    Naz, Huma; Islam, Asimul; Ahmad, Faizan; Hassan, Md Imtaiyaz

    2016-05-01

    The calcium/calmodulin-dependent protein kinase IV (CAMKIV) belongs to the serine/threonine protein kinase family, and is primarily involved in transcriptional regulation in lymphocytes, neurons and male germ cells. CAMKIV operates the signaling cascade and regulates activity of several transcription activators by phosphorylation, which in turn plays pivotal roles in immune response, inflammation and memory consolidation. In this review, we tried to focus on different aspects of CAMKIV to understand the significance of this protein in the biological system. This enzyme is associated with varieties of disorders such as cerebral hypoxia, azoospermia, endometrial and ovarian cancer, systemic lupus, etc., and hence it is considered as a potential therapeutic target. Structure of CAMKIV is comprised of five distinct domains in which kinase domain is responsible for enzyme activity. CAMKIV is involved in varieties of cellular functions such as regulation of gene expression, T-cell maturation, regulation of survival phase of dendritic cells, bone growth and metabolism, memory consolidation, sperm motility, regulation of microtubule dynamics, cell-cycle progression and apoptosis. In this review, we performed an extensive analysis on structure, function and regulation of CAMKIV and associated diseases. PMID:26773169

  9. Targeting voltage-gated calcium channels: developments in peptide and small-molecule inhibitors for the treatment of neuropathic pain

    OpenAIRE

    Vink, S.; Alewood, PF

    2012-01-01

    Chronic pain affects approximately 20% of people worldwide and places a large economic and social burden on society. Despite the availability of a range of analgesics, this condition is inadequately treated, with complete alleviation of symptoms rarely occurring. In the past 30 years, the voltage-gated calcium channels (VGCCs) have been recognized as potential targets for analgesic development. Although the majority of the research has been focused on Cav2.2 in particular, other VGCC subtypes...

  10. An amplified promoter system for targeted expression of calcium indicator proteins in the cerebellar cortex

    Directory of Open Access Journals (Sweden)

    Bernd eKuhn

    2012-07-01

    Full Text Available Recording of identified neuronal network activity using genetically encoded calcium indicators (GECIs requires labeling that is cell type-specific and bright enough for the detection of functional signals. However, specificity and strong expression are often not achievable using the same promoter. Here we present a combinatorial approach for targeted expression and single-cell-level quantification in which a weak promoter is used to drive trans-amplification under a strong general promoter. We demonstrated this approach using recombinant adeno-associated viruses (rAAVs to deliver the sequence of the GECI D3cpv in the mouse cerebellar cortex. Direct expression under the human synapsin promoter (hSYN led to high levels of expression (50-100 µM in five interneuron types of the cerebellar cortex but not in Purkinje cells (PCs (≤10 μM, yielding sufficient contrast to allow functional signals to be recorded from somata and processes in awake animals using two-photon microscopy. When the hSYN promoter was used to drive expression of the tetracycline transactivator (tTA, a second rAAV containing the bidirectional TET promoter (Ptetbi could drive strong D3cpv expression in PCs (10-300 µM, enough to allow reliable complex spike detection in the dendritic arbor. An amplified approach should be of use in monitoring neural processing in selected cell types and boosting expression of optogenetic probes. Additionally, we overcome cell toxicity associated with rAAV injection and/or local GECI overexpression by combining the virus injection with systemic pre-injection of hyperosmotic D-mannitol, and by this double the time window for functional imaging.

  11. Structural Insights into Membrane Targeting by the Flagellar Calcium-binding Protein (FCaBP) a Myristoylated and Palmitoylated Calcium Sensor in Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    J Wingard; J Ladner; M Vanarotti; A Fisher; H Robinson; K Buchanan; D Engman; J Ames

    2011-12-31

    The flagellar calcium-binding protein (FCaBP) of the protozoan Trypanosoma cruzi is targeted to the flagellar membrane where it regulates flagellar function and assembly. As a first step toward understanding the Ca{sup 2+}-induced conformational changes important for membrane-targeting, we report here the x-ray crystal structure of FCaBP in the Ca{sup 2+}-free state determined at 2.2{angstrom} resolution. The first 17 residues from the N terminus appear unstructured and solvent-exposed. Residues implicated in membrane targeting (Lys-19, Lys-22, and Lys-25) are flanked by an exposed N-terminal helix (residues 26-37), forming a patch of positive charge on the protein surface that may interact electrostatically with flagellar membrane targets. The four EF-hands in FCaBP each adopt a 'closed conformation' similar to that seen in Ca{sup 2+}-free calmodulin. The overall fold of FCaBP is closest to that of grancalcin and other members of the penta EF-hand superfamily. Unlike the dimeric penta EF-hand proteins, FCaBP lacks a fifth EF-hand and is monomeric. The unstructured N-terminal region of FCaBP suggests that its covalently attached myristoyl group at the N terminus may be solvent-exposed, in contrast to the highly sequestered myristoyl group seen in recoverin and GCAP1. NMR analysis demonstrates that the myristoyl group attached to FCaBP is indeed solvent-exposed in both the Ca{sup 2+}-free and Ca{sup 2+}-bound states, and myristoylation has no effect on protein structure and folding stability. We propose that exposed acyl groups at the N terminus may anchor FCaBP to the flagellar membrane and that Ca{sup 2+}-induced conformational changes may control its binding to membrane-bound protein targets..

  12. Proteomic analysis of imatinib-resistant CML-T1 cells reveals calcium homeostasis as a potential therapeutic target

    Science.gov (United States)

    Toman, O.; Kabickova, T.; Vit, O.; Fiser, R.; Polakova, K. Machova; Zach, J.; Linhartova, J.; Vyoral, D.; Petrak, J.

    2016-01-01

    Chronic myeloid leukemia (CML) therapy has markedly improved patient prognosis after introduction of imatinib mesylate for clinical use. However, a subset of patients develops resistance to imatinib and other tyrosine kinase inhibitors (TKIs), mainly due to point mutations in the region encoding the kinase domain of the fused BCR-ABL oncogene. To identify potential therapeutic targets in imatinib-resistant CML cells, we derived imatinib-resistant CML-T1 human cell line clone (CML-T1/IR) by prolonged exposure to imatinib in growth media. Mutational analysis revealed that the Y235H mutation in BCR-ABL is probably the main cause of CML-T1/IR resistance to imatinib. To identify alternative therapeutic targets for selective elimination of imatinib-resistant cells, we compared the proteome profiles of CML-T1 and CML-T1/IR cells using 2-DE-MS. We identified eight differentially expressed proteins, with strongly upregulated Na+/H+ exchanger regulatory factor 1 (NHERF1) in the resistant cells, suggesting that this protein may influence cytosolic pH, Ca2+ concentration or signaling pathways such as Wnt in CML-T1/IR cells. We tested several compounds including drugs in clinical use that interfere with the aforementioned processes and tested their relative toxicity to CML-T1 and CML-T1/IR cells. Calcium channel blockers, calcium signaling antagonists and modulators of calcium homeostasis, namely thapsigargin, ionomycin, verapamil, carboxyamidotriazole and immunosuppressive drugs cyclosporine A and tacrolimus (FK-506) were selectively toxic to CML-T1/IR cells. The putative cellular targets of these compounds in CML-T1/IR cells are postulated in this study. We propose that Ca2+ homeostasis can be a potential therapeutic target in CML cells resistant to TKIs. We demonstrate that a proteomic approach may be used to characterize a TKI-resistant population of CML cells enabling future individualized treatment options for patients. PMID:27430982

  13. Separation of no-carrier-added 62Zn from 7Li irradiated cobalt target using calcium alginate beads

    International Nuclear Information System (INIS)

    A 59Co target was irradiated with 47 MeV 7Li, which produced NCA 62Zn in the target matrix. NCA 62Zn was separated from the target matrix by adsorption on calcium alginate beads kept in HNO3 solutions of different pH values (1-6). The optimum separation condition was achieved at pH 5, where ∼83% NCA 62Zn was adsorbed on the alginate beads along with some contamination from the bulk Co. The complete separation of 62Zn from the bulk was achieved on desorbing Co from the beads with 0.1 M NaNO2. The remaining 62Zn was separated on re-adsorption under the same condition. (author)

  14. Systemic delivery of siRNA by hyaluronan-functionalized calcium phosphate nanoparticles for tumor-targeted therapy

    Science.gov (United States)

    Qiu, Chong; Wei, Wei; Sun, Jing; Zhang, Hai-Tao; Ding, Jing-Song; Wang, Jian-Cheng; Zhang, Qiang

    2016-06-01

    In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform spherical core-shell morphology with an approximate size of 170 nm and zeta potential of -12 mV. The coating of hydrophilic HA improved the physical stability of nanoparticles over one month due to the strong interactions between phosphonate and calcium. In vitro experiments demonstrated that the negatively charged CaP-AHA/siRNA NPs could effectively deliver EGFR-targeted siRNA into A549 cells through CD44-mediated endocytosis and significantly down-regulate the level of EGFR expression. Also, the internalized CaP-AHA/siRNA NPs exhibited a pH-responsive release of siRNA, indicating that the acidification of lysosomes probably facilitated the disassembling of nanoparticles and the resultant ions sharply increased the inner osmotic pressure and thus expedited the release of siRNA from late lysosomes into the cytoplasm. Furthermore, in vivo tumor therapy demonstrated that high accumulation of CaP-AHA/siEGFR NPs in tumor led to a significant tumor growth inhibition with a specific EGFR gene silencing effect after intravenous administration in nude mice xenografted with A549 tumor, along with a negligible body weight loss. These results suggested that the CaP-AHA/siRNA NPs could be an effective and safe systemic siRNA delivery system for a RNAi-based tumor targeted therapy strategy.In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform

  15. Proteomic analysis of imatinib-resistant CML-T1 cells reveals calcium homeostasis as a potential therapeutic target.

    Science.gov (United States)

    Toman, O; Kabickova, T; Vit, O; Fiser, R; Polakova, K Machova; Zach, J; Linhartova, J; Vyoral, D; Petrak, J

    2016-09-01

    Chronic myeloid leukemia (CML) therapy has markedly improved patient prognosis after introduction of imatinib mesylate for clinical use. However, a subset of patients develops resistance to imatinib and other tyrosine kinase inhibitors (TKIs), mainly due to point mutations in the region encoding the kinase domain of the fused BCR-ABL oncogene. To identify potential therapeutic targets in imatinib‑resistant CML cells, we derived imatinib-resistant CML-T1 human cell line clone (CML-T1/IR) by prolonged exposure to imatinib in growth media. Mutational analysis revealed that the Y235H mutation in BCR-ABL is probably the main cause of CML-T1/IR resistance to imatinib. To identify alternative therapeutic targets for selective elimination of imatinib-resistant cells, we compared the proteome profiles of CML-T1 and CML-T1/IR cells using 2-DE-MS. We identified eight differentially expressed proteins, with strongly upregulated Na+/H+ exchanger regulatory factor 1 (NHERF1) in the resistant cells, suggesting that this protein may influence cytosolic pH, Ca2+ concentration or signaling pathways such as Wnt in CML-T1/IR cells. We tested several compounds including drugs in clinical use that interfere with the aforementioned processes and tested their relative toxicity to CML-T1 and CML-T1/IR cells. Calcium channel blockers, calcium signaling antagonists and modulators of calcium homeostasis, namely thapsigargin, ionomycin, verapamil, carboxyamidotriazole and immunosuppressive drugs cyclosporine A and tacrolimus (FK-506) were selectively toxic to CML-T1/IR cells. The putative cellular targets of these compounds in CML-T1/IR cells are postulated in this study. We propose that Ca2+ homeostasis can be a potential therapeutic target in CML cells resistant to TKIs. We demonstrate that a proteomic approach may be used to characterize a TKI-resistant population of CML cells enabling future individualized treatment options for patients. PMID:27430982

  16. Calcium binding-mediated sustained release of minocycline from hydrophilic multilayer coatings targeting infection and inflammation.

    Directory of Open Access Journals (Sweden)

    Zhiling Zhang

    Full Text Available Infection and inflammation are common complications that seriously affect the functionality and longevity of implanted medical implants. Systemic administration of antibiotics and anti-inflammatory drugs often cannot achieve sufficient local concentration to be effective, and elicits serious side effects. Local delivery of therapeutics from drug-eluting coatings presents a promising solution. However, hydrophobic and thick coatings are commonly used to ensure sufficient drug loading and sustained release, which may limit tissue integration and tissue device communications. A calcium-mediated drug delivery mechanism was developed and characterized in this study. This novel mechanism allows controlled, sustained release of minocycline, an effective antibiotic and anti-inflammatory drug, from nanoscale thin hydrophilic polyelectrolyte multilayers for over 35 days at physiologically relevant concentrations. pH-responsive minocycline release was observed as the chelation between minocycline and Ca(2+ is less stable at acidic pH, enabling 'smart' drug delivery in response to infection and/or inflammation-induced tissue acidosis. The release kinetics of minocycline can be controlled by varying initial loading, Ca(2+ concentration, and Ca(2+ incorporation into different layers, enabling facile development of implant coatings with versatile release kinetics. This drug delivery platform can potentially be used for releasing any drug that has high Ca(2+ binding affinity, enabling its use in a variety of biomedical applications.

  17. New Conotoxin SO-3 Targeting N-type Voltage-Sensitive Calcium Channels

    Directory of Open Access Journals (Sweden)

    Lei Wen

    2006-04-01

    Full Text Available Selective blockers of the N-type voltage-sensitive calcium (CaV channels are useful in the management of severe chronic pain. Here, the structure and function characteristics of a novel N-type CaV channel blocker, SO-3, are reviewed. SO-3 is a 25-amino acid conopeptide originally derived from the venom of Conus striatus, and contains the same 4-loop, 6-cysteine framework (C-C-CC-C-C as O-superfamily conotoxins. The synthetic SO-3 has high analgesic activity similar to ω-conotoxin MVIIA (MVIIA, a selective N-type CaV channel blocker approved in the USA and Europe for the alleviation of persistent pain states. In electrophysiological studies, SO-3 shows more selectivity towards the N-type CaV channels than MVIIA. The dissimilarity between SO-3 and MVIIA in the primary and tertiary structures is further discussed in an attempt to illustrate the difference in selectivity of SO-3 and MVIIA towards N-type CaV channels.

  18. Mitochondria and calcium flux as targets of neuroprotection caused by minocycline in cerebellar granule cells

    OpenAIRE

    Garcia-Martinez, Eva Maria; Sanz-Blasco, Sara; Karachitos, Andonis; Bandez, Miguel J.; Fernandez-Gomez, Francisco J.; Perez-Alvarez, Sergio; Mera, Raquel Maria Melero Fernandez De; Jordan, Maria J.; Aguirre, Norberto; Galindo, Maria F.; Villalobos, Carlos; Navarro, Ana; Kmita, Hanna; Jordán, Joaquín

    2009-01-01

    Abstract Minocycline, an antibiotic of the tetracycline family, has attracted considerable interest for its theoretical therapeutic applications in neurodegenerative diseases. However, the mechanism of action underlying its effect remains elusive. Here we have studied the effect of minocycline under excitotoxic conditions. Fluorescence and bioluminescence imaging studies in rat cerebellar granular neuron cultures using fura-2/AM and mitochondria-targeted aequorin revealed that mino...

  19. Efficiency of calcium phosphate composite nanoparticles in targeting Ehrlich carcinoma cells transplanted in mice

    Directory of Open Access Journals (Sweden)

    Eman I. Abdel-Gawad

    2016-01-01

    Full Text Available The present study aimed to investigate the mode of action of nano-CaPs in vivo as a therapy for solid tumor in mice. To achieve this goal, Ehrlich Ascites Carcinoma (EAC was transplanted into 85 Swiss male albino mice. After nine days, the mice were divided into 9 groups. Groups 1 and 2 were allocated as the EAC control. Groups 3 and 4 were injected once intratumorally (IT by nano-calcium phosphate (nano-CaP. Groups 5 and 6 received once intraperitoneal injection (IP of nano-CaP. Groups 7, 8, and 9 received nano-CaP (IP weekly. Blood samples and thigh skeletal muscle were collected after three weeks from groups 1, 3, 5, and 7 and after four weeks from groups 2, 4, 6, and 8. On the other hand, group 9 received nano-CaP (IP for four weeks and lasted for three months to follow up the recurrence of tumor and to ensure the safety of muscle by histopathological analysis. Tumor growth was monitored twice a week throughout the experiment. DNA fragmentation of tumor cells was evaluated. In thigh tissue, noradrenaline, dopamine, serotonin (5HT, and gamma-aminobutyric acid (GABA were measured. In serum, 8-Hydroxy-deoxyguanosine (8-OHDG, adenosine triphosphate (ATP, and vascular endothelial growth factor (VEGF were analyzed. Histopathological and biochemical results showed a significant therapeutic effect of nano-CaP on implanted solid tumor and this effect was more pronounced in the animals treated IP for four weeks. This improvement was evident from the repair of fragmented DNA, the significant decrease of caspase-3, 8-OHDG, myosin, and VEGF, and the significant increase of neurotransmitters (NA, DA, 5HT, and GABA. Additionally, histopathological examination showed complete recovery of cancer cells in the thigh muscle after three months.

  20. Targeting voltage-gated calcium channels: developments in peptide and small-molecule inhibitors for the treatment of neuropathic pain.

    Science.gov (United States)

    Vink, S; Alewood, P F

    2012-11-01

    Chronic pain affects approximately 20% of people worldwide and places a large economic and social burden on society. Despite the availability of a range of analgesics, this condition is inadequately treated, with complete alleviation of symptoms rarely occurring. In the past 30 years, the voltage-gated calcium channels (VGCCs) have been recognized as potential targets for analgesic development. Although the majority of the research has been focused on Ca(v) 2.2 in particular, other VGCC subtypes such as Ca(v) 3.2 have recently come to the forefront of analgesic research. Venom peptides from marine cone snails have been proven to be a valuable tool in neuroscience, playing a major role in the identification and characterization of VGCC subtypes and producing the first conotoxin-based drug on the market, the ω-conotoxin, ziconotide. This peptide potently and selectively inhibits Ca(v) 2.2, resulting in analgesia in chronic pain states. However, this drug is only available via intrathecal administration, and adverse effects and a narrow therapeutic window have limited its use in the clinic. Other Ca(v) 2.2 inhibitors are currently in development and offer the promise of an improved route of administration and safety profile. This review assesses the potential of targeting VGCCs for analgesic development, with a main focus on conotoxins that block Ca(v) 2.2 and the developments made to transform them into therapeutics. PMID:22725651

  1. Stable Extended Human Immunodeficiency Virus Type 1 gp41 Coiled Coil as an Effective Target in an Assay for High-Affinity Fusion Inhibitors▿

    OpenAIRE

    Cai, Lifeng; Balogh, Edina; Gochin, Miriam

    2009-01-01

    The human immunodeficiency virus type 1 (HIV-1) gp41 coiled-coil domain is an important target for fusion inhibitors, including the peptide T20, which has been approved as a drug against HIV-1. Research into nonpeptide fusion inhibitors has focused primarily on a hydrophobic pocket located within the coiled coil and has so far yielded compounds with relatively weak fusion inhibitory activity. Here, we describe metal ion-assisted stabilization of an extended 39-residue construct of gp41, which...

  2. Calcium-activated potassium channels - a therapeutic target for modulating nitric oxide in cardiovascular disease?

    DEFF Research Database (Denmark)

    Dalsgaard, Thomas; Kroigaard, Christel; Simonsen, Ulf

    2010-01-01

    : Opening of SK and IK channels is associated with EDHF-type vasodilatation, but, through increased endothelial cell Ca(2+) influx, L-arginine uptake, and decreased ROS production, it may also lead to increased NO bioavailability and endothelium-dependent vasodilatation. TAKE HOME MESSAGE: Opening of SK and...... IK channels can increase both EDHF and NO-mediated vasodilatation. Therefore, openers of SK and IK channels may have the potential of improving endothelial cell function in cardiovascular disease.......-dependent vasodilatation is mediated by NO, prostacyclin, and an endothelium-derived hyperpolarising factor (EDHF), and involves small (SK) and intermediate (IK) conductance Ca(2+)-activated K(+) channels. Therefore, SK and IK channels may be drug targets for the treatment of endothelial dysfunction in cardiovascular...

  3. Separation of cyclotron-produced 44Sc from a natural calcium target using a dipentyl pentylphosphonate functionalized extraction resin

    Science.gov (United States)

    Valdovinos, H.F.; Hernandez, R.; Barnhart, T.E.; Graves, S.; Cai, W.; Nickles, R.J.

    2014-01-01

    Significant interest in 44Sc as a radioactive synthon to label small molecules for positron emission tomography (PET) imaging has been recently observed. Despite the efforts of several research groups, the ideal 44Sc production and separation method remains elusive. Herein, we propose a novel separation method to obtain 44Sc from the proton irradiation of calcium targets based on extraction chromatography, which promises to greatly simplify current production methodologies. Using the commercially available Uranium and Tetravalent Actinides (UTEVA) extraction resin we were able to rapidly ( 80% of the activity generated at end of bombardment (EoB) in small ~1 M HCl fractions (400 μL). The chemical purity of the 44Sc eluates was evaluated through chelation with DOTA and DTPA, and by trace metal analysis using microwave induced plasma atomic emission spectrometry. The distribution coefficients (Kd) of Sc(III) and Ca(II) in UTEVA were determined in HCl medium in a range of concentrations from zero to 12.1 M The 44Sc obtained with our method proved to be suitable for the direct labeling of small biomolecules for PET imaging, with excellent specific activities and radiochemical purity. PMID:25464172

  4. Calcium pectinate gel beads obtained from callus cultures pectins as promising systems for colon-targeted drug delivery.

    Science.gov (United States)

    Günter, Elena A; Popeyko, Oxana V

    2016-08-20

    Low methyl-esterified pectins obtained from the cell walls of the campion (SV, SV>300), tansy (TV, TV>300) and duckweed (LM, LM>300) callus cultures and apple pectin (AP, Classic AU 701) were used as the carriers for colon delivery of prednisolone. The pectins with molecular weight more than 300kDa (SV>300, TV>300, LM>300) formed gels which exhibited the higher gel strength. The higher gel strength of these gels appeared to be related to the higher Mw and the lower degree of methylesterification (DE) of these pectins. Release aspects of prednisolone in the simulated gastric (pH 1.25), intestinal (pH 7.0) and colonic (pH 7.0+pectinase) media were investigated. The LM-5%, AP-3% and AP-5% beads destroyed in simulated intestinal medium probably due to the higher DE of the LM and AP pectins. The SV>300-3% and TV>300-3% prednisolone loaded bead systems showed a high stability at pH 1.25 and pH 7.0. Prednisolone release occurred in a larger extent in colonic medium due to the enzymatic erosion of the beads. The SV>300-3% and TV>300-3% particles showed a more controlled release that appeared to be related to the lower DE, rhamnogalacturonan content, rhamnogalacturonan I branching and the higher linearity and Mw of the TV>300 and SV>300 pectins, as well as to the higher gel strength. This in vitro study suggests that calcium pectinate gel beads obtained from callus cultures pectins can be proposed as potential systems for colon-targeted drug delivery. PMID:27178956

  5. Nef decreases HIV-1 sensitivity to neutralizing antibodies that target the membrane-proximal external region of TMgp41.

    Directory of Open Access Journals (Sweden)

    Rachel P J Lai

    2011-12-01

    Full Text Available Primate lentivirus nef is required for sustained virus replication in vivo and accelerated progression to AIDS. While exploring the mechanism by which Nef increases the infectivity of cell-free virions, we investigated a functional link between Nef and Env. Since we failed to detect an effect of Nef on the quantity of virion-associated Env, we searched for qualitative changes by examining whether Nef alters HIV-1 sensitivity to agents that target distinct features of Env. Nef conferred as much as 50-fold resistance to 2F5 and 4E10, two potent neutralizing monoclonal antibodies (nAbs that target the membrane proximal external region (MPER of TMgp41. In contrast, Nef had no effect on HIV-1 neutralization by MPER-specific nAb Z13e1, by the peptide inhibitor T20, nor by a panel of nAbs and other reagents targeting gp120. Resistance to neutralization by 2F5 and 4E10 was observed with Nef from a diverse range of HIV-1 and SIV isolates, as well as with HIV-1 virions bearing Env from CCR5- and CXCR4-tropic viruses, clade B and C viruses, or primary isolates. Functional analysis of a panel of Nef mutants revealed that this activity requires Nef myristoylation but that it is genetically separable from other Nef functions such as the ability to enhance virus infectivity and to downregulate CD4. Glycosylated-Gag from MoMLV substituted for Nef in conferring resistance to 2F5 and 4E10, indicating that this activity is conserved in a retrovirus that does not encode Nef. Given the reported membrane-dependence of MPER-recognition by 2F5 and 4E10, in contrast to the membrane-independence of Z13e1, the data here is consistent with a model in which Nef alters MPER recognition in the context of the virion membrane. Indeed, Nef and Glycosylated-Gag decreased the efficiency of virion capture by 2F5 and 4E10, but not by other nAbs. These studies demonstrate that Nef protects lentiviruses from one of the most broadly-acting classes of neutralizing antibodies. This newly

  6. Structure and selectivity of novel ω-conotoxins and conus catus that target neuronal calcium channel subtypes

    International Nuclear Information System (INIS)

    Full text: ω-Conotoxins selective for N-type voltage-sensitive calcium channels have promising therapeutic applications in conditions such as pain and neurodegeneration following cerebral ischaemia. Here we report the discovery of novel conotoxins from the piscivorous snail Conus carus using 125I-GVIA binding to rat brain membrane to guide fractionation of crude venom, and cloning to identify the expressed gene products from the venom duct tissue. Four peptides were isolated and named ω-conotoxins CVIA-D (CVIA-D) on the basis of their pharmacology and structure. CVIA-D had varying extents of homology to other ω-conotoxins, with loop 4 of CVID showing significant sequence divergence. From binding studies in rat brain, the rank order of potency to displace 125I-GVIA from N-type calcium channel (CVID = GVIA=MVIIA > CVIA > CVIC = CVIB > MVIIC) was reversed at the P/Q-type calcium channel (defined by 125I-MVIIC). CVID was most selective for N-type vs P/Q-type calcium channels, being 1.5 to 2-orders of magnitude more selective than GVIA and MVIIA, respectively. CVIA-D each inhibited neurally-evoked contractions in rat vas deferens in a reversible manner, with potencies that correlated with their ability to inhibit 125I-GVIA binding. Compared with GVIA, CVID was a more potent inhibitor of central N-type calcium channels (α1,B-dexpressed in Xenopus oocytes) than of peripheral N-type calcium channels (rat vas deferens). 1H NMR studies revealed that CVID adopts a similar 3D fold to other ω-conotoxins. However, in contrast to GVIA, MVIIA or MVIIC, CVID has two hydrogen bonds that hold loops 2 and 4 proximal, a factor that may contribute to the enhanced ability of CVID to discriminate among neuronal calcium channels

  7. Butyrate increases intracellular calcium levels and enhances growth hormone release from rat anterior pituitary cells via the G-protein-coupled receptors GPR41 and 43.

    Directory of Open Access Journals (Sweden)

    Maria Consolata Miletta

    Full Text Available Butyrate is a short-chain fatty acid (SCFA closely related to the ketone body ß-hydroxybutyrate (BHB, which is considered to be the major energy substrate during prolonged exercise or starvation. During fasting, serum growth hormone (GH rises concomitantly with the accumulation of BHB and butyrate. Interactions between GH, ketone bodies and SCFA during the metabolic adaptation to fasting have been poorly investigated to date. In this study, we examined the effect of butyrate, an endogenous agonist for the two G-protein-coupled receptors (GPCR, GPR41 and 43, on non-stimulated and GH-releasing hormone (GHRH-stimulated hGH secretion. Furthermore, we investigated the potential role of GPR41 and 43 on the generation of butyrate-induced intracellular Ca2+ signal and its ultimate impact on hGH secretion. To study this, wt-hGH was transfected into a rat pituitary tumour cell line stably expressing the human GHRH receptor. Treatment with butyrate promoted hGH synthesis and improved basal and GHRH-induced hGH-secretion. By acting through GPR41 and 43, butyrate enhanced intracellular free cytosolic Ca2+. Gene-specific silencing of these receptors led to a partial inhibition of the butyrate-induced intracellular Ca2+ rise resulting in a decrease of hGH secretion. This study suggests that butyrate is a metabolic intermediary, which contributes to the secretion and, therefore, to the metabolic actions of GH during fasting.

  8. Calcium - urine

    Science.gov (United States)

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

  9. 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 ...

  10. Calcium Oscillations

    OpenAIRE

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  11. Analysis of Noncanonical Calcium-Dependent Protein Kinases in Toxoplasma gondii by Targeted Gene Deletion Using CRISPR/Cas9.

    Science.gov (United States)

    Long, Shaojun; Wang, Qiuling; Sibley, L David

    2016-05-01

    Calcium-dependent protein kinases (CDPKs) are expanded in apicomplexan parasites, especially in Toxoplasma gondii where 14 separate genes encoding these enzymes are found. Although previous studies have shown that several CDPKs play a role in controlling invasion, egress, and cell division in T. gondii, the roles of most of these genes are unexplored. Here we developed a more efficient method for gene disruption using CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9) that was modified to completely delete large, multiexonic genes from the genome and to allow serial replacement by recycling of the selectable marker using Cre-loxP. Using this system, we generated a total of 24 mutants in type 1 and 2 genetic backgrounds to ascertain the functions of noncanonical CDPKs. Remarkably, although we were able to confirm the essentiality of CDPK1 and CDPK7, the majority of CDPKs had no discernible phenotype for growth in vitro or infection in the mouse model. The exception to this was CDPK6, loss of which leads to reduced plaquing, fitness defect in a competition assay, and reduced tissue cyst formation in chronically infected mice. Our findings highlight the utility of CRISPR/Cas9 for rapid serial gene deletion and also suggest that additional models are needed to reveal the functions of many genes in T. gondii. PMID:26755159

  12. Broad neutralization of calcium-permeable amyloid pore channels with a chimeric Alzheimer/Parkinson peptide targeting brain gangliosides.

    Science.gov (United States)

    Di Scala, Coralie; Yahi, Nouara; Flores, Alessandra; Boutemeur, Sonia; Kourdougli, Nazim; Chahinian, Henri; Fantini, Jacques

    2016-02-01

    Growing evidence supports a role for brain gangliosides in the pathogenesis of neurodegenerative diseases including Alzheimer's and Parkinson's. Recently we deciphered the ganglioside-recognition code controlling specific ganglioside binding to Alzheimer's β-amyloid (Aβ1-42) peptide and Parkinson's disease-associated protein α-synuclein. Cracking this code allowed us to engineer a short chimeric Aβ/α-synuclein peptide that recognizes all brain gangliosides. Here we show that ganglioside-deprived neural cells do no longer sustain the formation of zinc-sensitive amyloid pore channels induced by either Aβ1-42 or α-synuclein, as assessed by single-cell Ca(2+) fluorescence microscopy. Thus, amyloid channel formation, now considered a key step in neurodegeneration, is a ganglioside-dependent process. Nanomolar concentrations of chimeric peptide competitively inhibited amyloid pore formation induced by Aβ1-42 or α-synuclein in cultured neural cells. Moreover, this peptide abrogated the intracellular calcium increases induced by Parkinson's-associated mutant forms of α-synuclein (A30P, E46K and A53T). The chimeric peptide also prevented the deleterious effects of Aβ1-42 on synaptic vesicle trafficking and decreased the Aβ1-42-induced impairment of spontaneous activity in rat hippocampal slices. Taken together, these data show that the chimeric peptide has broad anti-amyloid pore activity, suggesting that a common therapeutic strategy based on the prevention of amyloid-ganglioside interactions is a reachable goal for both Alzheimer's and Parkinson's diseases. PMID:26655601

  13. The small conductance calcium-activated potassium channel 3 (SK3) is a molecular target for Edelfosine to reduce the invasive potential of urothelial carcinoma cells.

    Science.gov (United States)

    Steinestel, Konrad; Eder, Stefan; Ehinger, Konstantin; Schneider, Juliane; Genze, Felicitas; Winkler, Eva; Wardelmann, Eva; Schrader, Andres J; Steinestel, Julie

    2016-05-01

    Metastasis is the survival-determining factor in urothelial carcinoma (UC) of the urinary bladder. The small conductance calcium-activated potassium channel 3 (SK3) enhances tumor cell invasion in breast cancer and malignant melanoma. Since Edelfosine, a glycerophospholipid with antitumoral properties, effectively inhibits SK3 channel activity, our goal was to evaluate SK3 as a potential molecular target to inhibit the gain of an invasive phenotype in UC. SK3 protein expression was analyzed in 208 tissue samples and UC cell lines. Effects of Edelfosine on SK3 expression and intracellular calcium levels as well as on cell morphology, cell survival and proliferation were assessed using immunoblotting, potentiometric fluorescence microscopy, and clonogenic/cell survival assay; furthermore, we analyzed the effect of Edelfosine and SK3 RNAi knockdown on tumor cell migration and invasion in vitro and in vivo. We found that SK3 is strongly expressed in muscle-invasive UC and in the RT112 cellular tumor model. Higher concentrations of Edelfosine have a strong antitumoral effect on UC cells, while 1 μM effectively inhibits migration/invasion of UC cells in vitro and in vivo comparable to the SK3 knockdown phenotype. Taken together, our results show strong expression of SK3 in muscle-invasive UC, consistent with the postulated role of the protein in tumor cell invasion. Edelfosine is able to effectively inhibit migration and invasion of UC cells in vitro and in vivo in an SK3-dependent way, pointing towards a possible role for Edelfosine as an antiinvasive drug to effectively inhibit UC cell invasion and metastasis. PMID:26619845

  14. A bivalent recombinant protein inactivates HIV-1 by targeting the gp41 prehairpin fusion intermediate induced by CD4 D1D2 domains

    Directory of Open Access Journals (Sweden)

    Lu Lu

    2012-12-01

    Full Text Available Abstract Background Most currently approved anti-HIV drugs (e.g., reverse transcriptase inhibitors, protease inhibitors and fusion/entry inhibitors must act inside or on surface of the target cell to inhibit HIV infection, but none can directly inactivate virions away from cells. Although soluble CD4 (sCD4 can inactivate laboratory-adapted HIV-1 strains, it fails to reduce the viral loads in clinical trials because of its low potency against primary isolates and tendency to enhance HIV-1 infection at low concentration. Thus, it is essential to design a better HIV inactivator with improved potency for developing new anti-HIV therapeutics that can actively attack the virus in the circulation before it attaches to and enter into the target cell. Results We engineered a bivalent HIV-1 inactivator, designated 2DLT, by linking the D1D2 domain of CD4 to T1144, the next generation HIV fusion inhibitor, with a 35-mer linker. The D1D2 domain in this soluble 2DLT protein could bind to the CD4-binding site and induce the formation of the gp41 prehairpin fusion-intermediate (PFI, but showed no sCD4-mediated enhancement of HIV-1 infection. The T1144 domain in 2DLT then bound to the exposed PFI, resulting in rapid inactivation of HIV-1 virions in the absence of the target cell. Beside, 2DLT could also inhibit fusion of the virus with the target cell if the virion escapes the first attack of 2DLT. Conclusion This bivalent molecule can serve as a dual barrier against HIV infection by first inactivating HIV-1 virions away from cells and then blocking HIV-1 entry on the target cell surface, indicating its potential for development as a new class of anti-HIV drug.

  15. Calcium Influx of Mast Cells Is Inhibited by Aptamers Targeting the First Extracellular Domain of Orai1

    Science.gov (United States)

    Sun, Renshan; Yang, Yongqiang; Ran, Xinze; Yang, Tao

    2016-01-01

    Using the systematic evolution of ligands by exponential enrichment (SELEX) method, we identified oligonucleotides that bind to the first extracellular domain of the Orai1 protein with high affinities and high specificities. These ligands were isolated from a random single-strand DNA (ssDNA) library with 40 randomized sequence positions, using synthesized peptides with amino acid sequences identical to the first extracellular domain of the Orai1 protein as the targets for SELEX selection. Seven aptamers were obtained after 12 rounds of SELEX. An enzyme-linked oligonucleotide assay (ELONA) was performed to determine the affinities of the aptamers. Aptamer Y1 had the highest affinity (Kd = 1.72×10−8 mol/L) and was selected for functional experiments in mast cells. Using LAD2 cells with the human high-affinity IgE receptor and Ca2+ release activation channel (CRAC), we demonstrated that Aptamer Y1 blocked IgE-mediated β-hexosaminidase release from cells triggered by biotin-IgE and streptavidin. A specific binding assay showed that Aptamer Y1 not only bound the Orai1 peptide specifically but also that the Orai1 peptide did not bind significantly to other random oligonucleotide molecules. Furthermore, Aptamer Y1 regulation of intracellular Ca2+ mobilization was investigated by probing intracellular Ca2+ with a Fluo-4-AM fluorescent probe. We found that Aptamer Y1 inhibits Ca2+ influx into antigen-activated mast cells. These results indicate that the target of Aptamer Y1 in the degranulation pathway is upstream of Ca2+ influx. Therefore, these oligonucleotide agents represent a novel class of CRAC inhibitors that may be useful in the fight against allergic diseases. PMID:27390850

  16. Short-chain free fatty acid receptors FFA2/GPR43 and FFA3/GPR41 as new potential therapeutic targets

    Directory of Open Access Journals (Sweden)

    Trond eUlven

    2012-10-01

    Full Text Available The deorphanization of the free fatty acid (FFA receptors FFA1 (GPR40, FFA2 (GPR43, FFA3 (GPR41, GPR84 and GPR120 made clear that the body is capable of recognizing and responding directly to nonesterified fatty acid of virtually any chain length. Colonic fermentation of dietary fiber produces high concentrations of the short-chain fatty acids (SCFAs acetate, propionate and butyrate, a process which is important to health. The phylogenetically related 7-transmembrane receptors free fatty acid receptor 2 (FFA2 and FFA3 are activated by these SCFAs, and several lines of evidence indicate that FFA2 and FFA3 mediate beneficial effects associated with a fiber-rich diet, and that they may be of interest as targets for treatment of inflammatory and metabolic diseases. FFA2 is highly expressed on immune cells, in particular neutrophils, and several studies suggest that the receptor plays a role in diseases involving a dysfunctional neutrophil response, such as inflammatory bowel disease (IBD. Both FFA2 and FFA3 have been implicated in metabolic diseases such as type 2 diabetes and regulation of appetite. More research is however required to clarify potential of the receptors as drug targets and establish if activation or inhibition would be the preferred mode of action. The availability of potent and selective receptor modulators is a prerequisite for these studies. The few modulators of FFA2 or FFA3 that have been published hitherto in the peer-reviewed literature in general have properties that make them less than ideal as such tools, but published patent applications indicate that the situation may soon improve, and that proper tool compounds will enable studies critical to validate the receptors as new drug targets.

  17. Diagnostic Phase of Calcium Scoring Scan Applied as the Center of Acquisition Window of Coronary Computed Tomography Angiography Improves Image Quality in Minimal Acquisition Window Scan (Target CTA Mode) Using the Second Generation 320-Row CT

    OpenAIRE

    Eriko Maeda; Kodai Yamamoto; Shigeaki Kanno; Kenji Ino; Nobuo Tomizawa; Masaaki Akahane; Rumiko Torigoe; Kuni Ohtomo

    2016-01-01

    Objective. To compare the image quality of coronary computed tomography angiography (CCTA) acquired under two conditions: 75% fixed as the acquisition window center (Group 75%) and the diagnostic phase for calcium scoring scan as the center (CS; Group CS). Methods. 320-row cardiac CT with a minimal acquisition window (scanned using “Target CTA” mode) was performed on 81 patients. In Group 75% (n = 40), CS was obtained and reconstructed at 75% and the center of the CCTA acquisition window was ...

  18. 4-(1-Ethyl-4-anisyl-imidazol-5-yl)-N-hydroxycinnamide – A new pleiotropic HDAC inhibitor targeting cancer cell signalling and cytoskeletal organisation

    Energy Technology Data Exchange (ETDEWEB)

    Mahal, Katharina, E-mail: katharina.mahal@uni-bayreuth.de [Organic Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth (Germany); Kahlen, Philip, E-mail: philip.kahlen@uni-bayreuth.de [Department of Genetics, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth (Germany); Biersack, Bernhard, E-mail: bernhard.biersack@yahoo.com [Organic Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth (Germany); Schobert, Rainer, E-mail: rainer.schobert@uni-bayreuth.de [Organic Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, 95440 Bayreuth (Germany)

    2015-08-15

    Histone deacetylases (HDAC) which play a crucial role in cancer cell proliferation are promising drug targets. However, HDAC inhibitors (HDACi) modelled on natural hydroxamic acids such as trichostatin A frequently lead to resistance or even an increased agressiveness of tumours. As a workaround we developed 4-(1-ethyl-4-anisyl-imidazol-5-yl)-N-hydroxycinnamide (etacrox), a hydroxamic acid that combines HDAC inhibition with synergistic effects of the 4,5-diarylimidazole residue. Etacrox proved highly cytotoxic against a panel of metastatic and resistant cancer cell lines while showing greater specificity for cancer over non-malignant cells when compared to the approved HDACi vorinostat. Like the latter, etacrox and the closely related imidazoles bimacroxam and animacroxam acted as pan-HDACi yet showed some specificity for HDAC6. Akt signalling and interference with nuclear beta-catenin localisation were elicited by etacrox at lower concentrations when compared to vorinostat. Moreover, etacrox disrupted the microtubule and focal adhesion dynamics of cancer cells and inhibited the proteolytic activity of prometastatic and proangiogenic matrix metalloproteinases. As a consequence, etacrox acted strongly antimigratory and antiinvasive against various cancer cell lines in three-dimensional transwell invasion assays and also antiangiogenic in vivo with respect to blood vessel formation in the chorioallantoic membrane assay. These pleiotropic effects and its water-solubility and tolerance by mice render etacrox a promising new HDACi candidate. - Graphical abstract: A novel histone deacetylase inhibitor with pleiotropic anticancer effects. - Highlights: • Etacrox is a new HDACi with cytotoxic, antiangiogenic and antiinvasive activity. • Etacrox causes aberrant cancer cell signalling and cytoskeletal reorganisation. • Pro-metastatic and angiogenic matrix metalloproteinases are inhibited by etacrox. • Etacrox impairs blood vessel maturation in vivo and cancer cell

  19. 4-(1-Ethyl-4-anisyl-imidazol-5-yl)-N-hydroxycinnamide – A new pleiotropic HDAC inhibitor targeting cancer cell signalling and cytoskeletal organisation

    International Nuclear Information System (INIS)

    Histone deacetylases (HDAC) which play a crucial role in cancer cell proliferation are promising drug targets. However, HDAC inhibitors (HDACi) modelled on natural hydroxamic acids such as trichostatin A frequently lead to resistance or even an increased agressiveness of tumours. As a workaround we developed 4-(1-ethyl-4-anisyl-imidazol-5-yl)-N-hydroxycinnamide (etacrox), a hydroxamic acid that combines HDAC inhibition with synergistic effects of the 4,5-diarylimidazole residue. Etacrox proved highly cytotoxic against a panel of metastatic and resistant cancer cell lines while showing greater specificity for cancer over non-malignant cells when compared to the approved HDACi vorinostat. Like the latter, etacrox and the closely related imidazoles bimacroxam and animacroxam acted as pan-HDACi yet showed some specificity for HDAC6. Akt signalling and interference with nuclear beta-catenin localisation were elicited by etacrox at lower concentrations when compared to vorinostat. Moreover, etacrox disrupted the microtubule and focal adhesion dynamics of cancer cells and inhibited the proteolytic activity of prometastatic and proangiogenic matrix metalloproteinases. As a consequence, etacrox acted strongly antimigratory and antiinvasive against various cancer cell lines in three-dimensional transwell invasion assays and also antiangiogenic in vivo with respect to blood vessel formation in the chorioallantoic membrane assay. These pleiotropic effects and its water-solubility and tolerance by mice render etacrox a promising new HDACi candidate. - Graphical abstract: A novel histone deacetylase inhibitor with pleiotropic anticancer effects. - Highlights: • Etacrox is a new HDACi with cytotoxic, antiangiogenic and antiinvasive activity. • Etacrox causes aberrant cancer cell signalling and cytoskeletal reorganisation. • Pro-metastatic and angiogenic matrix metalloproteinases are inhibited by etacrox. • Etacrox impairs blood vessel maturation in vivo and cancer cell

  20. Calcium Carbonate

    Science.gov (United States)

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

  1. 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<0.0001) or...

  2. Calcium Calculator

    Science.gov (United States)

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

  3. Amifostine-conjugated pH-sensitive calcium phosphate-covered magnetic-amphiphilic gelatin nanoparticles for controlled intracellular dual drug release for dual-targeting in HER-2-overexpressing breast cancer.

    Science.gov (United States)

    Li, Wei-Ming; Chiang, Chih-Sheng; Huang, Wei-Chen; Su, Chia-Wei; Chiang, Min-Yu; Chen, Jian-Yi; Chen, San-Yuan

    2015-12-28

    We developed a surfactant-free method utilizing amifostine to stably link a targeting ligand (Herceptin) to amphiphilic gelatin (AG)-iron oxide@calcium phosphate (CaP) nanoparticles with hydrophobic curcumin (CUR) and hydrophilic doxorubicin (DOX) encapsulated in the AG core and CaP shell (AGIO@CaP-CD), respectively. This multi-functional nanoparticle system has a pH-sensitive CaP shell and degradable amphiphilic gelatin (AG) core, which enables controllable sequential release of the two drugs. The dual-targeting system of AGIO@CaP-CD (HER-AGIO@CaP-CD) with a bioligand and magnetic targeting resulted in significantly elevated cellular uptake in HER2-overexpressing SKBr3 cells and more efficacious therapy than delivery of targeting ligand alone due to the synergistic cell multi-drug resistance/apoptosis-inducing effect of the CUR and DOX combination. This nanoparticle combined with Herceptin and iron oxide nanoparticles not only provided a dual-targeting functionality, but also encapsulated CUR and DOX as a dual-drug delivery system for the combination therapy. This study further demonstrated that the therapeutic efficacy of this dual-targeting co-delivery system can be improved by modifying the application duration of magnetic targeting, which makes this combination therapy system a powerful new tool for in vitro/in vivo cancer therapy, especially for HER2-positive cancers. PMID:26478017

  4. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  5. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

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

    2014-01-01

    homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m......Ab. This antibody was characterized by binding to CL-LK at hypo- and physiological calcium concentrations and dissociated from CK-LK at hyperphysiological concentrations of calcium. We purified CL-LK from plasma to a purity of 41% and a yield of 38%, resulting in a purification factor of more than 88......,000 in a single step. To evaluate the efficiency of this new purification scheme, we purified CL-LK using the same calcium-sensitive mAb in combination with acidic elution buffer and by using calcium-dependent anti-CL-K1 mAbs in combination with EDTA elution buffer. We found that calcium...

  6. Calcium and bones

    Science.gov (United States)

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

  7. Get Enough Calcium

    Science.gov (United States)

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

  8. Calcium carbonate overdose

    Science.gov (United States)

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

  9. Design, synthesis and activity assessment of aryl-substituent benzyl acid targeting HIV gp41%以艾滋病病毒gp41为靶点的芳基苯甲酸类化合物的设计、合成及活性评价

    Institute of Scientific and Technical Information of China (English)

    王海波; 陈之朋; 裘佳寅; 余小玲; 谢扬; 刘叔文

    2013-01-01

    目的 以艾滋病病毒(HIV)gp41为作用靶点,设计合成了12个含芳基取代的苯甲酸类化合物,并对其进行抗HIV活性测试.方法 以卤代苯甲酸或间羧基苯硼酸为原料,通过Suzuki-Miyaura偶连反应及Knoevenagel缩合反应,引入含取代基的芳环及芳杂环.ELISA法检测其抑制HIV gp41六螺旋束形成的活性.荧光素酶法检测化合物抗HIV活性.结果 化合物结构经NMR、MS得到确认,其中5个化合物(7b、7c、7d、7e、7g)具有抑制HIV gp41六螺旋束形成的活性,其中7d活性最强.该化合物能抑制HIV-1 SF33病毒株的复制,其IC50为20 μmol/L.结论 合成的芳基苯甲酸类化合物7d能通过抑制HIV gp41六螺旋束结构的形成来抑制HIV的复制.%Objective To synthesize novel aryl-substituent benzyl acid compounds targeting HIV gp41 and characterize their anti-HIV activities. Methods Twelve analogues of aryl-substituent benzyl acid were designed and synthesized by Suzuki-Miyaura cross-coupling and Knoevenagel condensation reactions using halo-benzyl acid or 3-carboxybenzeneboronic acid as the raw material. The inhibitory activities of these compounds on gp41 six-helix bundle formation were tested by ELISA, and their anti-HIV activities were determined using a luciferase assay. Results The structures of the compounds were characterized by nuclear magnetic resonance and mass spectrography. Among the 12 compounds, 5 (7b, 7c, 7d, 7e, and 7g) could inhibit the gp41 six-helix bundle formation, and 7d showed the most potent effect, and could also inhibit the replication of HIV-1 SF33 strain with an IC50 of 20 μmol/L. Conclusion The synthesized aryl-substituent benzyl acid compound 7d could inhibit HIV replication by blocking the gp41 six-helix bundle formation.

  10. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  11. Short-chain free fatty acid receptors FFA2/GPR43 and FFA3/GPR41 as new potential therapeutic targets

    OpenAIRE

    Ulven, Trond

    2012-01-01

    The deorphanization of the free fatty acid (FFA) receptors FFA1 (GPR40), FFA2 (GPR43), FFA3 (GPR41), GPR84, and GPR120 has made clear that the body is capable of recognizing and responding directly to nonesterified fatty acid of virtually any chain length. Colonic fermentation of dietary fiber produces high concentrations of the short-chain fatty acids (SCFAs) acetate, propionate and butyrate, a process which is important to health. The phylogenetically related 7-transmembrane (7TM) receptors...

  12. Short-chain free fatty acid receptors FFA2/GPR43 and FFA3/GPR41 as new potential therapeutic targets

    OpenAIRE

    Trond eUlven

    2012-01-01

    The deorphanization of the free fatty acid (FFA) receptors FFA1 (GPR40), FFA2 (GPR43), FFA3 (GPR41), GPR84 and GPR120 made clear that the body is capable of recognizing and responding directly to nonesterified fatty acid of virtually any chain length. Colonic fermentation of dietary fiber produces high concentrations of the short-chain fatty acids (SCFAs) acetate, propionate and butyrate, a process which is important to health. The phylogenetically related 7-transmembrane receptors free fatty...

  13. Zero-valent Fe confined mesoporous silica nanocarriers (Fe(0) @ MCM-41) for targeting experimental orthotopic glioma in rats.

    Science.gov (United States)

    Shevtsov, M A; Parr, M A; Ryzhov, V A; Zemtsova, E G; Arbenin, A Yu; Ponomareva, A N; Smirnov, V M; Multhoff, G

    2016-01-01

    Mesoporous silica nanoparticles (MSNs) impregnated with zero-valent Fe (Fe(0) @ MCM-41) represent an attractive nanocarrier system for drug delivery into tumor cells. The major goal of this work was to assess whether MSNs can penetrate the blood-brain barrier in a glioblastoma rat model. Synthesized MSNs nanomaterials were characterized by energy dispersive X-ray spectroscopy, measurements of X-ray diffraction, scanning electron microscopy and Mössbauer spectroscopy. For the detection of the MSNs by MR and for biodistribution studies MSNs were labeled with zero-valent Fe. Subsequent magnetometry and nonlinear-longitudinal-response-M2 (NLR-M2) measurements confirmed the MR negative contrast enhancement properties of the nanoparticles. After incubation of different tumor (C6 glioma, U87 glioma, K562 erythroleukemia, HeLa cervix carcinoma) and normal cells such as fibroblasts and peripheral blood mononuclear cells (PBMCs) MSNs rapidly get internalized into the cytosol. Intracellular residing MSNs result in an enhanced cytotoxicity as Fe(0) @ MCM-41 promote the reactive oxygen species production. MRI and histological studies indicated an accumulation of intravenously injected Fe(0) @ MCM-41 MSNs in orthotopic C6 glioma model. Biodistribution studies with measurements of second harmonic of magnetization demonstrated an increased and dose-dependent retention of MSNs in tumor tissues. Taken together, this study demonstrates that MSNs can enter the blood-brain barrier and accumulate in tumorous tissues. PMID:27386761

  14. Human cytomegalovirus microRNA miR-US4-1 inhibits CD8+ T cell response by targeting the aminopeptidase ERAP1

    OpenAIRE

    Kim, Sungchul; Lee, Sanghyun; Shin, Jinwook; Kim, Youngkyun; Evnouchidou, Irini; Kim, Donghyun; Kim, Young-Kook; Kim, Young-Eui; Ahn, Jin-Hyun; Riddell, Stanley R; Stratikos, Efstratios; Kim, V. Narry; Ahn, Kwangseog

    2011-01-01

    The major histocompatibility complex (MHC) class I molecules present peptides on the cell surface by CD8+ T cells, which is critical for killing of virally infected or transformed cells. Precursors of MHC class I-presented peptides are trimmed to mature epitopes by endoplasmic reticulum aminopeptidase 1 (ERAP1). The US2-US11 genomic region of human cytomegalovirus (HCMV) is dispensable for viral replication and harbors 3 microRNAs (miRNAs). We show here the HCMV miR-US4-1 specifically down-re...

  15. 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 ...

  16. Coronary Calcium Scan

    Science.gov (United States)

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

  17. 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 ...

  18. 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 ...

  19. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  20. 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 ...

  1. 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.

  2. Intracellular calcium is a target of modulation of apoptosis in MCF-7 cells in the presence of IgA adsorbed to polyethylene glycol

    Science.gov (United States)

    Honorio-França, Adenilda Cristina; Nunes, Gabriel Triches; Fagundes, Danny Laura Gomes; de Marchi, Patrícia Gelli Feres; Fernandes, Rubian Trindade da Silva; França, Juliana Luzia; França-Botelho, Aline do Carmo; Moraes, Lucélia Campelo Albuquerque; Varotti, Fernando de Pilla; França, Eduardo Luzía

    2016-01-01

    Purpose Clinical and epidemiological studies have indicated that breastfeeding has a protective effect on breast cancer risk. Protein-based drugs, including antibodies, are being developed to attain better forms of cancer therapy. Secretory IgA (SIgA) is the antibody class in human breast milk, and its activity can be linked to the protective effect of breastfeeding. The aim of this study was to investigate the effect of polyethylene glycol (PEG) microspheres with adsorbed SIgA on MCF-7 human breast cancer cells. Methods The PEG microspheres were characterized by flow cytometry and fluorescence microscopy. The MCF-7 cells were obtained from American Type Culture Collection. MCF-7 cells were pre-incubated for 24 hours with or without SIgA (100 ng/mL), PEG microspheres or SIgA adsorbed in PEG microspheres (100 ng/mL). Viability, intracellular calcium release, and apoptosis in MCF-7 cells were determined by flow cytometry. Results Fluorescence microscopy and flow cytometry analyses revealed that SIgA was able to adsorb to the PEG microspheres. The MCF-7 cells that were incubated with PEG microspheres with adsorbed SIgA showed decreased viability. MCF-7 cells that were incubated with SIgA or PEG microspheres with adsorbed SIgA had increased intracellular Ca2+ levels. In the presence of SIgA, an increase in the percentage of apoptotic cells was observed. The highest apoptosis index was observed when the cells were treated with PEG microspheres with adsorbed SIgA. Conclusion These data suggest that colostral SIgA adsorbed to PEG microspheres has antitumor effects on human MCF-7 breast cancer cells and that the presence of large amounts of this protein in secreted breast milk may provide protection against breast tumors in women who breastfed. PMID:26893571

  3. Calcium and Vitamin D

    Science.gov (United States)

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

  4. A bivalent recombinant protein inactivates HIV-1 by targeting the gp41 prehairpin fusion intermediate induced by CD4 D1D2 domains

    OpenAIRE

    Lu Lu; Pan Chungen; Li Yuan; Lu Hong; He Wu; Jiang Shibo

    2012-01-01

    Abstract Background Most currently approved anti-HIV drugs (e.g., reverse transcriptase inhibitors, protease inhibitors and fusion/entry inhibitors) must act inside or on surface of the target cell to inhibit HIV infection, but none can directly inactivate virions away from cells. Although soluble CD4 (sCD4) can inactivate laboratory-adapted HIV-1 strains, it fails to reduce the viral loads in clinical trials because of its low potency against primary isolates and tendency to enhance HIV-1 in...

  5. Short-chain free fatty acid receptors FFA2/GPR43 and FFA3/GPR41 as new potential therapeutic targets

    DEFF Research Database (Denmark)

    Ulven, Trond

    2012-01-01

    plays a role in diseases involving a dysfunctional neutrophil response, such as inflammatory bowel disease (IBD). Both FFA2 and FFA3 have been implicated in metabolic diseases such as type 2 diabetes and in regulation of appetite. More research is however required to clarify the potential of the...... general have properties that make them less than ideal as such tools, but published patent applications indicate that better tool compounds might soon become available which should enable studies critical to validate the receptors as new drug targets....

  6. Intracellular calcium is a target of modulation of apoptosis in MCF-7 cells in the presence of IgA adsorbed to polyethylene glycol

    Directory of Open Access Journals (Sweden)

    Honorio-França AC

    2016-02-01

    Full Text Available Adenilda Cristina Honorio-França,1 Gabriel Triches Nunes,1 Danny Laura Gomes Fagundes,1 Patrícia Gelli Feres de Marchi,1 Rubian Trindade da Silva Fernandes,1 Juliana Luzia França,1,2 Aline do Carmo França-Botelho,2 Lucélia Campelo Albuquerque Moraes,1 Fernando de Pilla Varotti,3 Eduardo Luzía França1,3 1Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil; 2Institute of Health Sciences, University Center of Planalto de Araxá, Araxá, Minas Gerais, Brazil; 3Campus Centro Oeste Dona Lindu – Federal University of São João Del Rei, Divinópolis, Minas Gerais, Brazil Purpose: Clinical and epidemiological studies have indicated that breastfeeding has a protective effect on breast cancer risk. Protein-based drugs, including antibodies, are being developed to attain better forms of cancer therapy. Secretory IgA (SIgA is the antibody class in human breast milk, and its activity can be linked to the protective effect of breastfeeding. The aim of this study was to investigate the effect of polyethylene glycol (PEG microspheres with adsorbed SIgA on MCF-7 human breast cancer cells.  Methods: The PEG microspheres were characterized by flow cytometry and fluorescence microscopy. The MCF-7 cells were obtained from American Type Culture Collection. MCF-7 cells were pre-incubated for 24 hours with or without SIgA (100 ng/mL, PEG microspheres or SIgA adsorbed in PEG microspheres (100 ng/mL. Viability, intracellular calcium release, and apoptosis in MCF-7 cells were determined by flow cytometry.  Results: Fluorescence microscopy and flow cytometry analyses revealed that SIgA was able to adsorb to the PEG microspheres. The MCF-7 cells that were incubated with PEG microspheres with adsorbed SIgA showed decreased viability. MCF-7 cells that were incubated with SIgA or PEG microspheres with adsorbed SIgA had increased intracellular Ca2+ levels. In the presence of SIgA, an increase in the

  7. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  8. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  9. Fenoprofen calcium overdose

    Science.gov (United States)

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  10. 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 ...

  11. 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 ...

  12. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  13. 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.

  14. Calcium en cardioplegie

    NARCIS (Netherlands)

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

    1985-01-01

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

  15. Calcium-Dependent Physiologic and Pathologic Stimulus-Metabolic Response Coupling in Hepatocytes

    OpenAIRE

    Gaspers, Lawrence D.; Mémin, Elisabeth; Thomas, Andrew P.

    2012-01-01

    A recurrent paradigm in calcium signaling is the coordination of the target response of the calcium signal with activation of metabolic energy production to support that response. This occurs in many tissues, including cardiac and skeletal muscle where contractile activity and ATP production are coordinately regulated by the frequency and amplitude of calcium transients, endocrine and exocrine cells that use calcium to drive the secretory process, and hepatocytes where the downstream targets ...

  16. In vitro calcium imaging of spinal cord dorsal horn neurons

    Czech Academy of Sciences Publication Activity Database

    Sojka, David; Paleček, Jiří

    Praha : The Czech Neuroscience Society, 2007. s. 41-41. [Conference of the Czech Neuroscience Society /6./. 19.11.2007-20.11.2007, Praha] R&D Projects: GA ČR(CZ) GA305/06/1115; GA MŠk(CZ) LC554; GA ČR(CZ) GD305/03/H148 Grant ostatní: MYORES(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : spo2 * calcium imaging * internal calcium stores * pain Subject RIV: FH - Neurology

  17. 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.

  18. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

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

    2001-01-01

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

  19. Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

    Directory of Open Access Journals (Sweden)

    Zhi Pan

    2014-02-01

    Full Text Available Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis.

  20. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

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

  1. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  2. 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...

  3. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

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

  4. Development and validation of fluorescence-based and automated patch clamp-based functional assays for the inward rectifier potassium channel Kir4.1.

    Science.gov (United States)

    Raphemot, Rene; Kadakia, Rishin J; Olsen, Michelle L; Banerjee, Sreedatta; Days, Emily; Smith, Stephen S; Weaver, C David; Denton, Jerod S

    2013-01-01

    The inward rectifier potassium (Kir) channel Kir4.1 plays essential roles in modulation of neurotransmission and renal sodium transport and may represent a novel drug target for temporal lobe epilepsy and hypertension. The molecular pharmacology of Kir4.1 is limited to neurological drugs, such as fluoxetine (Prozac(©)), exhibiting weak and nonspecific activity toward the channel. The development of potent and selective small-molecule probes would provide critically needed tools for exploring the integrative physiology and therapeutic potential of Kir4.1. A fluorescence-based thallium (Tl(+)) flux assay that utilizes a tetracycline-inducible T-Rex-HEK293-Kir4.1 cell line to enable high-throughput screening (HTS) of small-molecule libraries was developed. The assay is dimethyl sulfoxide tolerant and exhibits robust screening statistics (Z'=0.75±0.06). A pilot screen of 3,655 small molecules and lipids revealed 16 Kir4.1 inhibitors (0.4% hit rate). 3,3-Diphenyl-N-(1-phenylethyl)propan-1-amine, termed VU717, inhibits Kir4.1-mediated thallium flux with an IC50 of ∼6 μM. An automated patch clamp assay using the IonFlux HT workbench was developed to facilitate compound characterization. Leak-subtracted ensemble "loose patch" recordings revealed robust tetracycline-inducible and Kir4.1 currents that were inhibited by fluoxetine (IC50=10 μM), VU717 (IC50=6 μM), and structurally related calcium channel blocker prenylamine (IC50=6 μM). Finally, we demonstrate that VU717 inhibits Kir4.1 channel activity in cultured rat astrocytes, providing proof-of-concept that the Tl(+) flux and IonFlux HT assays can enable the discovery of antagonists that are active against native Kir4.1 channels. PMID:24266659

  5. Calcium D-saccharate

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  6. Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

    OpenAIRE

    Zhi Pan; Andrew Avila; Lauren Gollahon

    2014-01-01

    Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and...

  7. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  8. THE GENERATION,EVOLUTION AND PHYSIOLOGICAL RESPONSES OF INTRACELLUAR CALCIUM OSCILLATIONS AND WAVES

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-min

    2004-01-01

    The Atri intracellular calcium oscillations model was extended, and two new models were established. Furthermore, a unified model of the protein phosphorylation driven by cytosolic calcium oscillations was constructed. The numerical results obtained verified related experimental conclusions. And the analytical expressions of intracellular calcium spiral and target waves in the Xenopus laevis oocyte were obtained, resulting in velocity and waveform of calcium solitary pulse wave were found.

  9. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

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

    1993-01-01

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

  10. Revised Safety Instruction 41 (IS41 REV.)

    CERN Multimedia

    SC Secretariat

    2005-01-01

    Please note that the Revised Safety Instruction No. 41 (IS41 REV.), entitled 'The use of plastic and other non-metallic materials at CERN with respect to fire safety and radiation resistance' is available on the web at the following url: https://edms.cern.ch/document/335806/LAST_RELEASED Paper copies can also be obtained from the SC Unit Secretariat, e-mail: sc.secretariat@cern.ch SC Secretariat

  11. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  12. Should we prescribe calcium supplements for osteoporosis prevention?

    Science.gov (United States)

    Reid, Ian R

    2014-02-01

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

  13. 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...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  14. Voltage-Gated Calcium Channels in Nociception

    Science.gov (United States)

    Yasuda, Takahiro; Adams, David J.

    Voltage-gated calcium channels (VGCCs) are a large and functionally diverse group of membrane ion channels ubiquitously expressed throughout the central and peripheral nervous systems. VGCCs contribute to various physiological processes and transduce electrical activity into other cellular functions. This chapter provides an overview of biophysical properties of VGCCs, including regulation by auxiliary subunits, and their physiological role in neuronal functions. Subsequently, then we focus on N-type calcium (Cav2.2) channels, in particular their diversity and specific antagonists. We also discuss the role of N-type calcium channels in nociception and pain transmission through primary sensory dorsal root ganglion neurons (nociceptors). It has been shown that these channels are expressed predominantly in nerve terminals of the nociceptors and that they control neurotransmitter release. To date, important roles of N-type calcium channels in pain sensation have been elucidated genetically and pharmacologically, indicating that specific N-type calcium channel antagonists or modulators are particularly useful as therapeutic drugs targeting chronic and neuropathic pain.

  15. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

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

  16. The Effect of Calcium on the Binding of Calmodulin to Calcium/Calmodulin Protein Kinase II.

    Science.gov (United States)

    Porta, Angela R.

    2000-01-01

    Introduces a follow-up laboratory experiment demonstrating the formation change when calcium binds to calmodulin. This conformation change allows this complex to bind to a target protein. Presents the necessary information to conduct the experiment and discusses the results. (YDS)

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  18. The Availability of a Functional Tumor Targeting T-Cell Repertoire Determines the Anti-Tumor Efficiency of Combination Therapy with Anti-CTLA-4 and Anti-4-1BB Antibodies

    DEFF Research Database (Denmark)

    Jensen, Benjamin Anderschou Holbech; Pedersen, Sara R; Christensen, Jan P; Thomsen, Allan Randrup

    2013-01-01

    It has previously been found that combination therapy with anti-CTLA-4 and anti-4-1BB antibodies may enhance tumor immunity. However, this treatment is not efficient against all tumors, and it has been suggested that variations in tumor control may reflect differences in the immunogenicity of dif...

  19. Calcium wave of Brain Astrocytes

    Science.gov (United States)

    Cornell Bell, A. H.

    1997-03-01

    Time lapse confocal scanning laser microscopy was used to study hippocampal astrocyte cultures loaded with a calcium indicator, Fluo3-AM (4 uM). kThe neurotransmitter kainate (100uM) overwhelms the Na+-buffering capacity of astrocytes within 100 sec resulting in reversal of the Na+/Ca2+ exchanger. This results in a subcellular site where Ca2+ entering the cytoplasm contributes to a long-distance Ca2+ wave which travels at 20 um/sec without decrement. Image analysis has shown calcium waves not only at a high Kainate dose, but also at a low Kainate dose, e.g. 10uM. These are, however, shortlived and burried in an extremely noisy background and only detectable by analyzing the calcium waves images for spatio-temporal coherence. As the kainate dose increases, more large scale coherent structures with visible geometric features (spiral waves and target waves) can be observed. Multiple spiral waves are produced when the Kainate dose increases to 100 uM. These waves travel at a constant velocity across entire microscope fields for long time periods (>30 mins). Na+ channels have no effect on the Kainate wave. Voltage-gated Ca2+ channels are not involved and Ca2+ enters through reversal of the exchanger. Ca2+ release from stores does not contribute to the kainate wave. Removal of Na+ or Ca2+ from outside and the specific Na+/Ca2+ exchange inhibitor benzamil (10 uM) inhibit the kainate wave. A functional antibody to alpha6-Integrin which is localized to membrane regions between cells inhibits the spread of the kainate wave in a dose and time-dependent manner. Fluorescence Recovery after Photobleach (FRAP) techniques indicate that gap junctions remain open between cells. This would imply that Ca2+ or IP3 need not pass through the gap junction, but reversal of the exchanger would propel the Ca2+ wave at the cell surface.

  20. 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

  1. Strength of the $E_{\\text{p}}$=1.842 MeV resonance in the $^{40}$Ca(p,$\\gamma$)$^{41}$Sc reaction revisited

    CERN Document Server

    Schmidt, Konrad; Anders, Michael; Bemmerer, Daniel; Caciolli, Antonio; Dietz, Mirco; Elekes, Zoltán; Junghans, Arnd R; Menzel, Marie-Luise; Schwengner, Ronald; Wagner, Andreas; Zuber, Kai

    2014-01-01

    The strength of the $E_{\\rm p} = 1.842$ MeV resonance in the $^{40}$Ca(p,$\\gamma$)$^{41}$Sc reaction is determined with two different methods: First, by an absolute strength measurement using calcium hydroxide targets, and second, relative to the well-determined strength of the resonance triplet at $E_\\alpha$ = 4.5 MeV in the $^{40}$Ca($\\alpha$,$\\gamma$)$^{44}$Ti reaction. The present new value of $\\omega\\gamma=(0.192\\pm0.017)$ eV is 37% (equivalent to $3.5\\sigma$) higher than the evaluated literature value. In addition, the ratio of the strengths of the 1.842 MeV $^{40}$Ca(p,$\\gamma$)$^{41}$Sc and 4.5 MeV $^{40}$Ca($\\alpha$,$\\gamma$)$^{44}$Ti resonances has been determined to be $0.0229\\pm0.0018$. The newly corrected strength of the 1.842-MeV resonance can be used in the future as a normalization point for experiments with calcium targets.

  2. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  3. CALCIUM SOAP LUBRICANTS

    OpenAIRE

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

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

    Science.gov (United States)

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

  5. SERCA1 truncated proteins unable to pump calcium reduce the endoplasmic reticulum calcium concentration and induce apoptosis.

    Science.gov (United States)

    Chami, M; Gozuacik, D; Lagorce, D; Brini, M; Falson, P; Peaucellier, G; Pinton, P; Lecoeur, H; Gougeon, M L; le Maire, M; Rizzuto, R; Bréchot, C; Paterlini-Bréchot, P

    2001-06-11

    By pumping calcium from the cytosol to the ER, sarco/endoplasmic reticulum calcium ATPases (SERCAs) play a major role in the control of calcium signaling. We describe two SERCA1 splice variants (S1Ts) characterized by exon 4 and/or exon 11 splicing, encoding COOH terminally truncated proteins, having only one of the seven calcium-binding residues, and thus unable to pump calcium. As shown by semiquantitative RT-PCR, S1T transcripts are differentially expressed in several adult and fetal human tissues, but not in skeletal muscle and heart. S1T proteins expression was detected by Western blot in nontransfected cell lines. In transiently transfected cells, S1T homodimers were revealed by Western blot using mildly denaturing conditions. S1T proteins were shown, by confocal scanning microscopy, to colocalize with endogenous SERCA2b into the ER membrane. Using ER-targeted aequorin (erAEQ), we have found that S1T proteins reduce ER calcium and reverse elevation of ER calcium loading induced by SERCA1 and SERCA2b. Our results also show that SERCA1 variants increase ER calcium leakage and are consistent with the hypothesis of a cation channel formed by S1T homodimers. Finally, when overexpressed in liver-derived cells, S1T proteins significantly induce apoptosis. These data reveal a further mechanism modulating Ca(2+) accumulation into the ER of nonmuscle cells and highlight the relevance of S1T proteins to the control of apoptosis. PMID:11402072

  6. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

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

  7. Children's Bone Health and Calcium

    Science.gov (United States)

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

  8. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

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

  9. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

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

  10. Calcium deposits in the common carotid artery

    International Nuclear Information System (INIS)

    Complete text of publication follows. Arterial calcification consists mainly of calcium apatite and takes place at two sites in the vessel wall: the intima and the media. Intimal calcification occurs exclusively within atherosclerotic plaques, while medial calcification may develop independently [1]. Ultrasound examination of the carotid arteries is performed routinely to assess pathological alterations. Large calcified plaques in the carotid arteries can be detected by B-mode ultrasonography easily as high frequency ultrasound does not penetrate calcium and have been investigated extensively. In this study our aim was to determine the calcium distribution in the vessel wall itself, excluding large plaques, and to make the first step towards investigating the relationship between the calcium distributional maps and the respective ultrasonic images. The carotid arteries of five elderly (age 71±9 years) and one young (age 27 years) deceased patients were excised at autopsy and were investigated with a medical ultrasound equipment in a tank containing saline solution. Scan sequences were videotaped and images of previously marked cross-sections were transferred to a computer. Small pieces of the arteries were cut and quench frozen. Sections of 60μm from the middle of the scanned segments (30mm proximal to the bifurcation) were cut in a cryostat. The cryosections were transferred to microprobe target holders. The elemental distribution of the samples were determined by particle induced X-ray emission (PIXE) at the Debrecen microprobe [2]. True elemental maps and absolute concentration values were evaluated with a new software (True Pixe Imaging) [3]. The average calcium content of the scanned areas varied between 1000 and 9000μg/g in the slices of the common carotid arteries of the elderly patients. In contrast, scanned areas in the slices from the young subject contained only 600-800μg/g calcium. The concentration of calcium could reach even 3.75% along the wide

  11. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  12. 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...... renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis....

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

    Directory of Open Access Journals (Sweden)

    Haiyan eLi

    2011-11-01

    Full Text Available Synaptic transmission involves the calcium-dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-shifted reporter of vesicle recycling based on a vesicular glutamate transporter, VGLUT1-mOrange2 (VGLUT1-mOr2, and a presynaptically-localized green calcium indicator, synaptophysin-GCaMP3 (SyGCaMP3 with a large dynamic range. The fluorescence of VGLUT1-mOr2 is quenched by the low pH of synaptic vesicles. Exocytosis upon electrical stimulation exposes the luminal mOr2 to the neutral extracellular pH and relieves fluorescence quenching. Re-acidification of the vesicle upon endocytosis again reduces fluorescence intensity. Changes in fluorescence intensity thus monitor synaptic vesicle exo- and endocytosis, as demonstrated previously for the green VGLUT1-pHluorin. To monitor changes in calcium, we fused the synaptic vesicle protein synaptophysin to the recently improved calcium indicator GCaMP3. SyGCaMP3 is targeted to presynaptic varicosities, and exhibits changes in fluorescence in response to electrical stimulation consistent with changes in calcium concentration. Using real-time imaging of both reporters expressed in the same synapses, we determine the time course of changes in VGLUT1 recycling in relation to changes in presynaptic calcium concentration. Inhibition of P/Q- and N-type calcium channels reduces calcium levels, as well as the rate of synaptic vesicle exocytosis and the fraction of vesicles released.

  14. Concurrent Imaging of Synaptic Vesicle Recycling and Calcium Dynamics

    Science.gov (United States)

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

    2011-01-01

    Synaptic transmission involves the calcium dependent release of neurotransmitter from synaptic vesicles. Genetically encoded optical probes emitting different wavelengths of fluorescent light in response to neuronal activity offer a powerful approach to understand the spatial and temporal relationship of calcium dynamics to the release of neurotransmitter in defined neuronal populations. To simultaneously image synaptic vesicle recycling and changes in cytosolic calcium, we developed a red-shifted reporter of vesicle recycling based on a vesicular glutamate transporter, VGLUT1-mOrange2 (VGLUT1-mOr2), and a presynaptically localized green calcium indicator, synaptophysin-GCaMP3 (SyGCaMP3) with a large dynamic range. The fluorescence of VGLUT1-mOr2 is quenched by the low pH of synaptic vesicles. Exocytosis upon electrical stimulation exposes the luminal mOr2 to the neutral extracellular pH and relieves fluorescence quenching. Reacidification of the vesicle upon endocytosis again reduces fluorescence intensity. Changes in fluorescence intensity thus monitor synaptic vesicle exo- and endocytosis, as demonstrated previously for the green VGLUT1-pHluorin. To monitor changes in calcium, we fused the synaptic vesicle protein synaptophysin to the recently improved calcium indicator GCaMP3. SyGCaMP3 is targeted to presynaptic varicosities, and exhibits changes in fluorescence in response to electrical stimulation consistent with changes in calcium concentration. Using real time imaging of both reporters expressed in the same synapses, we determine the time course of changes in VGLUT1 recycling in relation to changes in presynaptic calcium concentration. Inhibition of P/Q- and N-type calcium channels reduces calcium levels, as well as the rate of synaptic vesicle exocytosis and the fraction of vesicles released. PMID:22065946

  15. Biological sample preparation and 41Ca AMS measurement at LLNL

    International Nuclear Information System (INIS)

    Calcium metabolism in biology may be better understood by the use of 41Ca tracer, although requiring detection by accelerator mass spectrometry (AMS). Methodologies for preparation of urine samples and subsequent AMS measurement were investigated. Novel attempts at preparing CaH2 were unsuccessful, but CaF2 of sufficient purity could be produced by precipitation of calcium from urine as oxalate, followed by separation of calcium by cation exchange chromatography and washing the CaF2 precipitate. The presence of some remaining impurities could be compensated for by selecting the appropriate accelerated ion charge state for AMS. The use of projectile X-rays for isobar discrimination was explored as an alternative to the co nventional dE/dx detector. (orig.)

  16. Interaction of H2S with Calcium Permeable Channels and Transporters

    Directory of Open Access Journals (Sweden)

    Weihua Zhang

    2015-01-01

    Full Text Available A growing amount of evidence has suggested that hydrogen sulfide (H2S, as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC, T-type calcium channels (TTCC, sodium/calcium exchangers (NCX, transient receptor potential (TRP channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms.

  17. Fruit Calcium: Transport and Physiology

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

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

  18. Fruit Calcium: Transport and Physiology.

    Science.gov (United States)

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

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

  19. Lipid body accumulation alters calcium signaling dynamics in immune cells

    Science.gov (United States)

    Greineisen, William E.; Speck, Mark; Shimoda, Lori M.N.; Sung, Carl; Phan, Nolwenn; Maaetoft-Udsen, Kristina; Stokes, Alexander J.; Turner, Helen

    2014-01-01

    Summary There is well-established variability in the numbers of lipid bodies (LB) in macrophages, eosinophils, and neutrophils. Similarly to the steatosis observed in adipocytes and hepatocytes during hyperinsulinemia and nutrient overload, immune cell LB hyper-accumulate in response to bacterial and parasitic infection and inflammatory presentations. Recently we described that hyperinsulinemia, both in vitro and in vivo, drives steatosis and phenotypic changes in primary and transformed mast cells and basophils. LB reach high numbers in these steatotic cytosols, and here we propose that they could dramatically impact the transcytoplasmic signaling pathways. We compared calcium release and influx responses at the population and single cell level in normal and steatotic model mast cells. At the population level, all aspects of FcεRI-dependent calcium mobilization, as well as activation of calcium-dependent downstream signalling targets such as NFATC1 phosphorylation are suppressed. At the single cell level, we demonstrate that LB are both sources and sinks of calcium following FcεRI cross-linking. Unbiased analysis of the impact of the presence of LB on the rate of trans-cytoplasmic calcium signals suggest that LB enrichment accelerates calcium propagation, which may reflect a Bernoulli effect. LB abundance thus impacts this fundamental signalling pathway and its downstream targets. PMID:25016314

  20. The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential

    OpenAIRE

    Gerald W Zamponi; Striessnig, Joerg; Koschak, Alexandra; Dolphin, Annette C.

    2015-01-01

    Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type ...

  1. Calcium and calcitonin responses to calcium infusion in type I diabetes mellitus.

    OpenAIRE

    Amado, J. A.; C. Gomez; Obaya, S.; Otero, M; Gonzalez-Macias, J

    1987-01-01

    We studied calcium and calcium and calcitonin responses to intravenous calcium infusion (3 mg of elemental calcium/kg of body weight in 10 minutes) in 21 type I diabetic males and 17 age-matched normal males. Baseline total calcium, parathyroid hormone and calcitonin levels were normal in the diabetic group, but ionized calcium was lowered. Cortical bone status and osteocalcin levels were normal, suggesting a normal osteoblastic function. Total calcium and ionized calcium responses to calcium...

  2. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

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

  3. 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...

  4. Direct Imaging of Hippocampal Epileptiform Calcium Motifs Following Kainic Acid Administration in Freely Behaving Mice.

    Science.gov (United States)

    Berdyyeva, Tamara K; Frady, E Paxon; Nassi, Jonathan J; Aluisio, Leah; Cherkas, Yauheniya; Otte, Stephani; Wyatt, Ryan M; Dugovic, Christine; Ghosh, Kunal K; Schnitzer, Mark J; Lovenberg, Timothy; Bonaventure, Pascal

    2016-01-01

    novel drug screening paradigms and therapeutics designed to target and abolish abnormal patterns of both electrical and calcium excitation. PMID:26973444

  5. Reverse calcium affinity purification of Fab with calcium derivatized hydroxyapatite

    OpenAIRE

    Gagnon, Pete; Cheung, Chia-wei; Yazaki, Paul J.

    2009-01-01

    This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell culture supernatants. Alternatively, Fab can be concentrated on native hydroxyapatite then eluted s...

  6. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    OpenAIRE

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  7. 4.1 Introduction

    Science.gov (United States)

    Noßke, D.; Mattsson, S.; Johansson, L.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '4.1 Introduction' of the Chapter '4 Dosimetry in Nuclear Medicine Diagnosis and Therapy' with the contents:

  8. Calcium-dependent activation of Pyk2 by hypoxia.

    Science.gov (United States)

    Beitner-Johnson, Dana; Ferguson, Tsuneo; Rust, Randy T; Kobayashi, Shuichi; Millhorn, David E

    2002-02-01

    The Pyk2 tyrosine kinase can be activated by both calcium-dependent and calcium-independent mechanisms. Exposure to moderate hypoxia (5% O(2)) induced a rapid and persistent tyrosine phosphorylation of Pyk2 in pheochromocytoma (PC12) cells. Hypoxia and KCl-depolarization increased the phosphotyrosine content of Pyk2 by twofold and fourfold, respectively. Both of these effects were abolished in the absence of extracellular calcium. There was a modest activation of MAPK in parallel with the onset of Pyk2 phosphorylation. However, there was no detectable activation of either JNK or c-src, two other known downstream targets of Pyk2. Thus, exposure to hypoxia may selectively target specific subsets of Pyk2 signalling pathways. PMID:11781137

  9. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

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

  10. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Moilanen, A.; Norby, P.; Papadakis, K.; Posselt, D.; Sørensen, L. H.

    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...

  11. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

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

  12. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

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

  13. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  14. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

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

  15. PYRETHROID INDUCED ALTERATIONS IN TRANSCRIPTION OF CALCIUM RESPONSIVE AND IMMEDIATE EARLY GENES IN VIVO.

    Science.gov (United States)

    Multiple molecular targets for pyrethroid insecticides have been evaluated in in vitro preparations, including but not limited to voltage-sensitive sodium channels (VSSCs), voltage-sensitive calcium channels (VSCCs), GABAergic receptors, ATPases and mitochondrial respiratory chai...

  16. Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.

    OpenAIRE

    Simon, S M; Llinás, R R

    1985-01-01

    Quantitative modeling indicates that, in presynaptic terminals, the intracellular calcium concentration profile during inward calcium current is characterized by discrete peaks of calcium immediately adjacent to the calcium channels. This restriction of intracellular calcium concentration suggests a remarkably well specified intracellular architecture such that calcium, as a second messenger, may regulate particular intracellular domains with a great degree of specificity.

  17. Fibroblast-Like Synoviocytes Induce Calcium Mineral Formation and Deposition

    Directory of Open Access Journals (Sweden)

    Yubo Sun

    2014-01-01

    Full Text Available Calcium crystals are present in the synovial fluid of 65%–100% patients with osteoarthritis (OA and 20%–39% patients with rheumatoid arthritis (RA. This study sought to investigate the role of fibroblast-like synoviocytes (FLSs in calcium mineral formation. We found that numerous genes classified in the biomineral formation process, including bone gamma-carboxyglutamate (gla protein/osteocalcin, runt-related transcription factor 2, ankylosis progressive homolog, and parathyroid hormone-like hormone, were differentially expressed in the OA and RA FLSs. Calcium deposits were detected in FLSs cultured in regular medium in the presence of ATP and FLSs cultured in chondrogenesis medium in the absence of ATP. More calcium minerals were deposited in the cultures of OA FLSs than in the cultures of RA FLSs. Examination of the micromass stained with nonaqueous alcoholic eosin indicated the presence of birefringent crystals. Phosphocitrate inhibited the OA FLSs-mediated calcium mineral deposition. These findings together suggest that OA FLSs are not passive bystanders but are active players in the pathological calcification process occurring in OA and that potential calcification stimuli for OA FLSs-mediated calcium deposition include ATP and certain unidentified differentiation-inducing factor(s. The OA FLSs-mediated pathological calcification process is a valid target for the development of disease-modifying drug for OA therapy.

  18. A Convenient Approach to Heterocyclic Building Blocks: Synthesis of Novel Ring Systems Containing a [5,6]Pyrano[2,3-c]pyrazol-4(1H-one Moiety

    Directory of Open Access Journals (Sweden)

    Wolfgang Holzer

    2007-01-01

    Full Text Available Starting from commercially available educts, a straightforward synthetic route to new heterocyclic building blocks is exemplified with the one- or two-step synthesis of tri-, tetra-, or pentacyclic ring systems. Representatives of the following novel ring systems are prepared from 3-methyl-1-phenyl-2-pyrazolin-5-one and the corresponding o-halo-arenecarbonyl chloride using calcium hydroxide in refluxing 1,4-dioxane: pyrimidino[4',5':5,6]pyrano[2,3-c]pyrazol-4(1H-one, thieno[3',2':5,6]pyrano[2,3c]pyrazol- 4-(1H-one, thieno[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H-one, thieno[3'',2'':4',5']thieno[2',3':5,6]-pyrano[2,3-c]pyrazol-4(1H-one, [1,3]dioxolo[5',6'][1]benzothieno[2',3':5,6]pyrano-[2,3-c]- pyrazol-4(1H-one, pyridazino[4',3':5,6]pyrano[2,3-c]pyrazol-4(1H-one and pyrazolo-[4'',3'':5',6']pyrido[3',4':5,6]pyrano[2,3-c]pyrazol-4(1H-one. While the latter two ring systems are directly obtained due to a spontaneous intramolecular substitution reaction, in the other reactions uncyclised 4-aroylpyrazol-5-ols are produced, which are cyclised into the target heterocycles in a subsequent synthetic step (i.e. treatment with NaH in DMF. Detailed NMR spectroscopic investigations (1H-, 13C-, 15N- with the obtained compounds were undertaken to unambiguously prove the new structures.

  19. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

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

  20. 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 ...

  1. Melittin binding causes a large calcium-dependent conformational change in calmodulin.

    OpenAIRE

    Kataoka, M.(LAPP, CNRS/IN2P3 and Université de Savoie, Annecy-le-Vieux, France); Head, J F; Seaton, B A; Engelman, D M

    1989-01-01

    The interaction between calmodulin and its target protein is a key step in many calcium-regulated cellular functions. Melittin binds tightly to calmodulin in the presence of calcium and is a competitive inhibitor of calmodulin function. Using melittin as a model for the target peptide of calmodulin, we have found a large Ca2+-dependent conformational change of calmodulin in solution induced by peptide binding. Mg2+ does not substitute for Ca2+ in producing the conformation change. Small-angle...

  2. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa). Ouabain reversed JnetCa to an absorptive flux. Amiloride reduced both fluxes such that JnetCa 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, JnetCa decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca 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 Ca2+-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

  3. An Improved Calcium Flame Test.

    Science.gov (United States)

    Pearson, Robert S.

    1985-01-01

    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  4. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    OpenAIRE

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

  6. Antiviral properties of two trimeric recombinant gp41 proteins

    Directory of Open Access Journals (Sweden)

    Nisole Sébastien

    2006-03-01

    Full Text Available Abstract Background As it is the very first step of the HIV replication cycle, HIV entry represents an attractive target for the development of new antiviral drugs. In this context, fusion inhibitors are the third class of anti-HIV drugs to be used for treatment, in combination with nucleoside analogues and antiproteases. But the precise mechanism of HIV fusion mechanism is still unclear. Gp41 ectodomain-derived synthetic peptides represent ideal tools for clarifying this mechanism, in order to design more potent anti-HIV drugs. Results Two soluble trimeric recombinant gp41 proteins, termed Rgp41B and Rgp41A were designed. Both comprise the N- and C-terminal heptad repeat regions of the ectodomain of HIV-1 gp41, connected by a 7-residue hydrophilic linker, in order to mimic the trimeric fusogenic state of the transmembrane glycoprotein. Both recombinant proteins were found to inhibit HIV-1 entry into target cells in a dose-dependent manner. Rgp41A, the most potent inhibitor, was able to inhibit both X4 and R5 isolates into HeLa cells and primary T lymphocytes. X4 viruses were found to be more susceptible than R5 isolates to inhibition by Rgp41A. In order to elucidate how the trimeric recombinant gp41 protein can interfere with HIV-1 entry into target cells, we further investigated its mode of action. Rgp41A was able to bind gp120 but did not induce gp120-gp41 dissociation. Furthermore, this inhibitor could also interfere with a late step of the fusion process, following the mixing of lipids. Conclusion Taken together, our results suggest that Rgp41A can bind to gp120 and also interfere with a late event of the fusion process. Interestingly, Rgp41A can block membrane fusion without preventing lipid mixing. Although further work will be required to fully understand its mode of action, our results already suggest that Rgp41A can interfere with multiple steps of the HIV entry process.

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

    Institute of Scientific and Technical Information of China (English)

    Nasrin NFJATBAKHSH; Zhong-ping FENG

    2011-01-01

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

  8. Documentation of spectrom-41

    International Nuclear Information System (INIS)

    SPECTROM-41 is a finite element heat transfer computer program developed to analyze thermal problems related to nuclear waste disposal. The code is part of the SPECTROM (Special Purpose Engineering Codes for Thermal/ROck Mechanics) series of special purpose finite element programs that are continually being developed by RE/SPEC Inc. (RSI) to address the many unique formations. This document presents the theoretical basis for the mathematical model, the finite element formulation of the program, and a description of the input data for the program, along with details about program support and continuing documentation. The documentation is intended to satisfy the requirements and guidelines outlined in NUREG-0856. The principal component model used in the programs based on Fourier's law of conductance. Numerous program options provide the capability of considering various boundary conditions, material stratification and anisotropy, and time-dependent heat generation that are characteristic of problems involving the disposal of nuclear waste in geologic formation. Numerous verification problems are included in the documentation in addition to highlights of past and ongoing verification and validation efforts. A typical repository problem is solving using SPECTROM-41 to demonstrate the use of the program in addressing problems related to the disposal of nuclear waste

  9. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

    Gooding, J. L.; Wentworth, S. J.

    1987-01-01

    Chips of glassy Lithology C of EETA79001 were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy to determine the mineralogy and petrogenesis of the glass that was shown by others to contain trapped Mars-like gases. Calcium carbonite was identified as massive to acicular crystals for which Ca, C, and O were the major elements. Calcium sulfate was identified as prismatic-acicular crystals with Ca and S as the major elements.

  10. Calcium channel blocking activity of fruits of callistemon citrinus

    International Nuclear Information System (INIS)

    Callistemon citrinus is a plant of family myrtaceae that has a great medicinal importance. Traditional uses of the aerial parts of Callistemon citrinus in ethnic tribal communities are in practice, and very little are known about its importance on scientific grounds. Therefore, the crude methanolic extract of fruits of Callistemon citrinus (C.c) was screened for possible spasmolytic activity on isolated rabbit's jejunum preparations. The extract produced a relaxing effect on spontaneous contraction of rabbit's jejunum. Explaining the mode of action, the extract produced a dose dependent relaxant effect and shifted the calcium response curves to the rightward (EC50 +- SEM = -2.05 +- 0.05 vs. control EC50 +- SEM = -2.5 +- 0.05). The effect of extract was comparable with the effect of verapamil, a standard calcium channel blocker and therefore, the plant specie could be a potential target for isolation of calcium antagonist(s). (author)

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

    OpenAIRE

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

    2015-01-01

    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 Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dy...

  12. Urine risk factors in children with calcium kidney stones and their siblings.

    Science.gov (United States)

    Bergsland, Kristin J; Coe, Fredric L; White, Mark D; Erhard, Michael J; DeFoor, William R; Mahan, John D; Schwaderer, Andrew L; Asplin, John R

    2012-06-01

    Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. PMID:22358148

  13. Serum Calcium Concentration Is Inversely Associated With Radiographic Knee Osteoarthritis

    OpenAIRE

    Li, Hui; ZENG, CHAO; Wei, Jie; Yang, Tuo; GAO, SHU-GUANG; Li, Yu-Sheng; Luo, Wei; Xiao, Wen-feng; Xiong, Yi-lin; LEI, GUANG-HUA

    2016-01-01

    Abstract To examine the relationship between serum calcium (Ca) concentration and radiographic knee osteoarthritis (OA). This study covered a total of 2855 subjects. The serum Ca concentration was detected by the Arsenazo III method. The radiographic OA of the knee was defined as changes equivalent to Kellgren–Lawrence grade 2 on 1 side at least. The serum Ca concentration was categorized into 4 quartiles, which are ≤2.27, 2.28–2.34, 2.35–2.41, and ≥2.42 mmol/L, respectively. The relationship...

  14. Variability of calcium absorption

    International Nuclear Information System (INIS)

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

  15. Evolution and functional diversity of the Calcium Binding Proteins (CaBPs

    Directory of Open Access Journals (Sweden)

    Lee P Haynes

    2012-02-01

    Full Text Available The mammalian central nervous system (CNS exhibits a remarkable ability to process, store and transfer information. Key to these activities is the use of highly regulated and unique patterns of calcium signals encoded by calcium channels and decoded by families of specific calcium-sensing proteins. The largest family of eukaryotic calcium sensors are those related to the small EF-hand containing protein calmodulin (CaM. In order to maximise the usefulness of calcium as a signalling species and to permit the evolution and fine tuning of the mammalian CNS, families of related proteins have arisen that exhibit characteristic calcium binding properties and tissue-, cellular- and sub-cellular distribution profiles. The Calcium Binding Proteins (CaBPs represent one such family of vertebrate specific calmodulin like proteins that have emerged in recent years as important regulators of essential neuronal target proteins. Bioinformatic analyses indicate that the CaBPs consist of two subfamilies and that the ancestral members of these are CaBP1 and CaBP8. The CaBPs have distinct intracellular localisations based on different targeting mechanisms including a novel type-II transmembrane domain in CaBPs 7 and 8. Recent work has led to the identification of new target interactions and possible functions for the CaBPs suggesting that they have multiple physiological roles with relevance for the normal functioning of the CNS.

  16. Emanuel Strehler’s work on calcium pumps and calcium signaling

    Institute of Scientific and Technical Information of China (English)

    Emanuel; E; Strehler

    2011-01-01

    Cells are equipped with mechanisms to control tightly the influx, efflux and resting level of free calcium (Ca 2+ ). Inappropriate Ca 2+ signaling and abnormal Ca 2+ levels are involved in many clinical disorders including heart disease, Alzheimer’s disease and stroke. Ca 2+ also plays a major role in cell growth, differentiation and motility; disturbances in these processes underlie cell transformation and the progression of cancer. Accordingly, research in the Strehler laboratory is focused on a better understanding of the molecular "toolkit" needed to ensure proper Ca 2+ homeostasis in the cell, as well as on the mechanisms of localized Ca 2+ signaling. A longterm focus has been on the plasma membrane calcium pumps (PMCAs), which are linked to multiple disorders including hearing loss, neurodegeneration, and heart disease. Our work over the past 20 years or more has revealed a surprising complexity of PMCA isoforms with different functional characteristics, regulation, and cellular localization. Emerging evidence shows how specific PMCAs contribute not only to setting basal intracellular Ca 2+ levels, but also to local Ca 2+ signaling and vectorial Ca 2+ transport. A second major research arearevolves around the calcium sensor protein calmodulin and an enigmatic calmodulin-like protein (CALML3) that is linked to epithelial differentiation. One of the cellular targets of CALML3 is the unconventional motor protein myosin-10, which raises new questions about the role of CALML3 and myosin-10 in cell adhesion and migration in normal cell differentiation and cancer.

  17. "Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

    OpenAIRE

    1989-01-01

    We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to...

  18. Effect of Preharvest Calcium Treatments on Sweet Cherry Fruit Quality

    OpenAIRE

    Deniz EROGUL

    2014-01-01

    In this study, the effects of different foliar calcium compounds on fruit cracking and quality of sweet cherry variety ‘0900 Ziraat’ were investigated. Calcium caseinate, calcium chloride, calcium hydroxide and calcium nitrate were used as foliar sprays. Calcium applications reduced the cracking index 38% to 66% compared to cherries that did not receive foliar treatment. The most efficient applications for decreasing cracking were calcium hydroxide and calcium chloride. Calcium chloride and c...

  19. 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 ...

  20. Isotope targets prepared by vapor deposition

    International Nuclear Information System (INIS)

    As the state of the art for producing thin films has developed, the parameters set by the experiments have in turn become more stringent. Often these targets must be of high purity, extremely thin, self-supporting, and of accurately determined thickness. In addition, the target material may be an expensive isotope which must be reduced to elemental form at the time of vapor deposition. Methods of producing some of these targets will be discussed with such examples as calcium, magnesium and boron

  1. Aging and calcium as an environmental factor.

    Science.gov (United States)

    Fujita, T

    1985-12-01

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

  2. Transport of Calcium Ions into Mitochondria.

    Science.gov (United States)

    Xu, Zhaolong; Zhang, Dayong; He, Xiaolan; Huang, Yihong; Shao, Hongbo

    2016-06-01

    To uptake calcium ions of mitochondria is of significant functional connotation for cells, because calcium ions in mitochondria are involved in energy production, regulatory signals transfer, and mitochondrial permeability transition pore opening and even programmed cell death of apoptosis, further playing more roles in plant productivity and quality. Cytoplasmic calcium ions access into outer mitochondrial membrane (OMM) from voltage dependent anion-selective channel (VDAC) and were absorbed into inner mitochondrial membrane (IMM) by mitochondrial calcium uniporter (MCU), rapid mitochondrial calcium uptake (RaM) or mitochondrial ryanodine receptor (mRyR). Although both mitochondria and the mechanisms of calcium transport have been extensively studied, but there are still long-standing or even new challenges. Here we review the history and recent discoveries of the mitochondria calcium ions channel complex involved calcium assimilation, and discuss the role of calcium ions into mitochondria. PMID:27252588

  3. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

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

    2015-11-01

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

  4. The genetic background affects the vascular response in T-type calcium channels 3.2 deficient mice

    DEFF Research Database (Denmark)

    Svenningsen, Per; Hansen, Pernille B L

    2016-01-01

    -type channels are the dominant Ca(2+) entry pathway in vascular smooth muscle cells, however, T-type calcium channels are also expressed in the cardiovascular system where they play a functional role in the regulation of both contraction and vasodilation in (Chen et al. 2003; Hansen et al. 2001). This article......Voltage-gated calcium channels (Cav ) are important regulators of vascular tone and are attractive targets for pharmacological treatment of hypertension. The clinical used calcium blockers are often not selective for one channel but affect several types of calcium channels (Hansen 2015). L...

  5. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    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 Ca9Sr(PO4)6(OH)2 - CaSr9(PO4)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

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

    OpenAIRE

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    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 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intes...

  7. moco: Fast Motion Correction for Calcium Imaging.

    Science.gov (United States)

    Dubbs, Alexander; Guevara, James; Yuste, Rafael

    2016-01-01

    Motion correction is the first step in a pipeline of algorithms to analyze calcium imaging videos and extract biologically relevant information, for example the network structure of the neurons therein. Fast motion correction is especially critical for closed-loop activity triggered stimulation experiments, where accurate detection and targeting of specific cells in necessary. We introduce a novel motion-correction algorithm which uses a Fourier-transform approach, and a combination of judicious downsampling and the accelerated computation of many L 2 norms using dynamic programming and two-dimensional, fft-accelerated convolutions, to enhance its efficiency. Its accuracy is comparable to that of established community-used algorithms, and it is more stable to large translational motions. It is programmed in Java and is compatible with ImageJ. PMID:26909035

  8. Multimodal encoding in a simplified model of intracellular calcium signaling

    OpenAIRE

    De Pitta`, Maurizio; Volman, Vladislav; Levine, Herbert; Ben-Jacob, Eshel

    2009-01-01

    Many cells use calcium signalling to carry information from the extracellular side of the plasma membrane to targets in their interior. Since virtually all cells employ a network of biochemical reactions for Ca2+ signalling, much effort has been devoted to understand the functional role of Ca2+ responses and to decipher how their complex dynamics is regulated by the biochemical network of Ca2+-related signal transduction pathways. Experimental observations show that Ca2+ signals in response t...

  9. Virus and calcium : an unexpected tandem to optimize insecticide efficacy

    OpenAIRE

    Apaire-Marchais, V; Ogliastro, M.; Chandre, Fabrice; Pennetier, Cédric; Raymond, V; Lapied, B

    2016-01-01

    The effective control of insect pests is based on the rational use of the most efficient and safe insecticide treatments. To increase the effects of classical insecticides and to avoid the ability of certain pest insects to develop resistance, it is essential to propose novel strategies. Previous studies have shown that calcium-dependent phosphorylation/dephosphorylation is now considered as a new cellular mechanism for increasing the target sensitivity to insecticides. Because it is known th...

  10. Remodeling of Calcium Handling in Human Heart Failure

    OpenAIRE

    Lou, Qing; Janardhan, Ajit; Efimov, Igor R.

    2012-01-01

    Heart failure (HF) is an increasing public health problem accelerated by a rapidly aging global population. Despite considerable progress in managing the disease, the development of new therapies for effective treatment of HF remains a challenge. To identify targets for early diagnosis and therapeutic intervention, it is essential to understand the molecular and cellular basis of calcium handling and the signaling pathways governing the functional remodeling associated with HF in humans. Calc...

  11. Octupole strength in the neutron-rich calcium isotopes

    CERN Document Server

    Riley, L A; Agiorgousis, M L; Baugher, T R; Bazin, D; Bowry, M; Cottle, P D; DeVone, F G; Gade, A; Glowacki, M T; Gregory, S D; Haldeman, E B; Kemper, K W; Lunderberg, E; Noji, S; Recchia, F; Sadler, B V; Scott, M; Weisshaar, D; Zegers, R G T

    2016-01-01

    Low-lying excited states of the neutron-rich calcium isotopes $^{48-52}$Ca have been studied via $\\gamma$-ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA $\\gamma$-ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.

  12. Calcium Supplementation to Prevent Preeclampsia: Translating Guidelines into Practice in Low-Income Countries.

    Science.gov (United States)

    Omotayo, Moshood O; Dickin, Katherine L; O'Brien, Kimberly O; Neufeld, Lynnette M; De Regil, Luz Maria; Stoltzfus, Rebecca J

    2016-03-01

    The WHO issued a strong recommendation that pregnant women be provided calcium supplements to prevent preeclampsia. This is the first recommended nutritional intervention to prevent this condition, a leading cause of maternal mortality globally. As health systems seek to implement this new intervention, a number of issues require further clarification and guidance, including dosage regimen, supplement formulation, and alignment with other antenatal nutritional interventions. We summarize key evidence on the above points and offer our views on good practices. Most developing countries have low calcium intake, so where habitual calcium intake is unknown, calcium supplements are likely beneficial. In our view, policymakers and program planners should consider adopting doses between 1.0 and 1.5 g elemental calcium/d, depending on the local average and variation in dietary calcium intake, logistical feasibility, and acceptability in the target population. Prudent practice would entail daily administration as calcium carbonate administered in divided doses of not >500 mg elemental calcium per dose. For ease of prescribing and adherence, calcium [as with iron and folic acid (IFA)] should be administered routinely to pregnant women from the earliest contact in pregnancy until delivery. Calcium's acute inhibitory effect on iron absorption translates to minimal effects in clinical studies. Therefore, to simplify the regimen and facilitate adherence, providers should not counsel that calcium and IFA pills must be taken separately. Although further research will shed more light on clinical and programmatic issues, policies can be implemented with ongoing revision as we continue to learn what works to improve maternal and newborn health. PMID:26980810

  13. Biodiesel from sunflower oil in supercritical methanol with calcium oxide

    International Nuclear Information System (INIS)

    In this study, sunflower seed oil was subjected to the transesterification reaction with calcium oxide (CaO) in supercritical methanol for obtaining biodiesel. Methanol is used most frequently as the alcohol in the transesterification process. Calcium oxide (CaO) can considerably improve the transesterification reaction of sunflower seed oil in supercritical methanol. The variables affecting the methyl ester yield during the transesterification reaction, such as the catalyst content, reaction temperature and the molar ratio of soybean oil to alcohol, were investigated and compared with those of non-catalyst runs. The catalytic transesterification ability of CaO is quite weak under ambient temperature. At a temperature of 335 K, the yield of methyl ester is only about 5% in 3 h. When CaO was added from 1.0% to 3.0%, the transesterification speed increased evidently, while when the catalyst content was further enhanced to 5%, the yield of methyl ester slowly reached to a plateau. It was observed that increasing the reaction temperature had a favorable influence on the methyl ester yield. In addition, for molar ratios ranging from 1 to 41, as the higher molar ratios of methanol to oil were charged, the greater transesterification speed was obtained. When the temperature was increased to 525 K, the transesterification reaction was essentially completed within 6 min with 3 wt% CaO and 41:1 methanol/oil molar ratio

  14. Calcium and lithium ion production for laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M.; Palm, K.; Stifler, C.; Steski, D.; Ikeda, S.; Kumaki, M.; Kanesue, T.

    2015-08-23

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) to simulate the effects of cosmic radiation. To find out difficulties to provide such high reactive material as laser targets, the both species were experimentally tested. Plate-shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6ns, 1064nm Nd:YAG laser. We found significant oxygen contamination in both the Ca and Li high-charge-state beams due to the rapid oxidation of the surfaces. A large-spot-size, low-power-density laser was then used to analyze the low-charge-state beams without scanning the targets. The low-charge-state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely with a low-power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low-power shot. To measure the rate of oxidation, we shot the low-power laser at the target repeatedly at 10sec, 30sec, 60sec, and 120sec interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

  15. Calcium and lithium ion production for laser ion source

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, M., E-mail: okamura@bnl.gov [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Palm, K. [Department of Physics, Cornell University, Ithaca, New York 14853-2501 (United States); Stifler, C. [Engineering Physics Systems Department, Providence College, Providence, Rhode Island 02918 (United States); Steski, D.; Kanesue, T. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa (Japan); Kumaki, M. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo (Japan)

    2016-02-15

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

  16. Calcium and lithium ion production for laser ion source

    International Nuclear Information System (INIS)

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam

  17. Calcium and lithium ion production for laser ion source

    Science.gov (United States)

    Okamura, M.; Palm, K.; Stifler, C.; Steski, D.; Ikeda, S.; Kumaki, M.; Kanesue, T.

    2016-02-01

    Calcium and lithium ion beams are required by NASA Space Radiation Laboratory at Brookhaven National Laboratory to simulate the effects of cosmic radiation. To identify the difficulties in providing such highly reactive materials as laser targets, both species were experimentally tested. Plate shaped lithium and calcium targets were fabricated to create ablation plasmas with a 6 ns 1064 nm neodymium-doped yttrium aluminum garnet laser. We found significant oxygen contamination in both the Ca and Li high charge state beams due to the rapid oxidation of the surfaces. A large spot size, low power density laser was used to create low charge state beams without scanning the targets. The low charge state Ca beam did not have any apparent oxygen contamination, showing the potential to clean the target entirely of oxide with a low power beam once in the chamber. The Li target was clearly still oxidizing in the chamber after each low power shot. To measure the rate of oxidation, we shot the low power laser at the target repeatedly at 10 s, 30 s, 60 s, and 120 s interval lengths, showing a linear relation between the interval time and the amount of oxygen in the beam.

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

    Science.gov (United States)

    Hoth, M; Penner, R

    1993-06-01

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

  19. Microanalyses of the hydroxyl—poly—calcium sodium phosphate coatings produced by ion beam assisted deposition

    Institute of Scientific and Technical Information of China (English)

    LIUZhong-Yang; WANGChang-Xing; 等

    2002-01-01

    Thin calcium phosphate catings on titanium alloy substrates were prepared by Ar+ ion beam assisted deposition(IBAD) from hydroxyl-poly-calcium sodium phosphate(HPPA) target.The coatings were analyzed by XRD,FTIR,XPS,These analyses revealed that the as-deposited films were amorphous or no apparent crystallinity.No distinct absorption band of the hydroxyl group was observed in FTIR spectra of the coatings but new absorption bands were presented for CO3-2,The calcium to phosphorous ratio of these catings in different IBAD conditions varied from 0.46 to 3.36.

  20. Calcium phosphate in catheter encrustation.

    Science.gov (United States)

    Cox, A J; Harries, J E; Hukins, D W; Kennedy, A P; Sutton, T M

    1987-02-01

    Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline. PMID:3030487

  1. Calcium Binding by Ro 60 Multiple Antigenic Peptides on PVDF Membrane.

    Science.gov (United States)

    Kurien, Biji T; Bachmann, Michael P

    2015-01-01

    Antibodies directed against ribonucleoprotein (RNP) particles are observed in systemic lupus erythematosus. Ro RNP particle is one such target. It is composed of a 60 kDa protein (Ro 60 or SS-A) that is non-covalently associated with at least one of the four short uridine-rich RNAs (the hY RNAs). Previously, we showed that multiple antigenic peptides (MAPs) made from the sequence of the Ro 60 autoantigen could be used, using double-immunodiffusion studies, enzyme-linked immunosorbant assay, affinity chromatography, and surface plasmon resonance, to show intramolecular and intermolecular protein-protein interaction within the Ro 60 RNP particle. We also observed that calcium is important in mediating this interaction. We hypothesized, therefore, that 60 kDa Ro is a calcium-binding protein. To investigate this, we electrophoresed 60 kDa Ro MAPs, transferred them to PVDF membrane, and assayed calcium binding using the Quin-2 system. Several Ro 60 MAPs were found to bind calcium using this assay, as well as bovine serum albumin, another calcium-binding protein. However, a MAP constructed from the Sm autoantigen did not bind to calcium. These data, along with our observation regarding the involvement of calcium in protein-protein interaction occurring between Ro 60 antigen and Ro 60 MAPs, makes us propose that Ro 60 antigen is a calcium-binding protein. PMID:26139264

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

    Science.gov (United States)

    Chu, J.

    1971-01-01

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

  3. Preparation of calcium carbonate particles coated with titanium dioxide

    Institute of Scientific and Technical Information of China (English)

    Hai Lin; Ying-bo Dong; Le-yong Jiang

    2009-01-01

    The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was stud-ied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanochemi-eal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5:3.5. The mass ratios of two different types of titanium dioxide (anatase to rutile) and grinding media to grinded materials were 8:2 and 4:1 respec-tively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification.The hiding power and oil absorption of this new material were 29.12 g/m~2 and 23.30%, respectively. The results show that the modi-fication is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be im-proved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.

  4. Tumoral calcium pyrophosphate deposition disease

    International Nuclear Information System (INIS)

    A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a women aged 71 years, the lesion involved the tissues adjacent to the right hip. Each lesion consisted of a mass of highly cellular tissue containing deposits of calcium pyrophosphate dihydrate crystals. The clinical, radiological, and pathological features of the two cases are compared with those of seven similar cases reported in the literature. (orig.)

  5. Particle physics using nuclear targets

    Energy Technology Data Exchange (ETDEWEB)

    Ferbel, T.

    1978-01-01

    The use of nuclear targets in particle physics is discussed and some recent results obtained in studies of hadronic interactions on nuclei summarized. In particular experimental findings on inclusive production and on coherent dissociation of mesons and baryons at high energies are presented. 41 references.

  6. Particle physics using nuclear targets

    International Nuclear Information System (INIS)

    The use of nuclear targets in particle physics is discussed and some recent results obtained in studies of hadronic interactions on nuclei summarized. In particular experimental findings on inclusive production and on coherent dissociation of mesons and baryons at high energies are presented. 41 references

  7. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  8. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

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

  9. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

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

  10. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  11. Structure elucidation of alkaline earth impregnated MCM-41 type mesoporous materials obtained by direct synthesis: An experimental and theoretical study

    Science.gov (United States)

    Paz, Gizeuda L.; Silva, Francisco das Chagas M.; Araújo, Maciel M.; Lima, Francisco das Chagas A.; Luz, Geraldo E.

    2014-06-01

    In this work, MCM-41 were synthesized hydrothermally and functionalized with calcium and strontium salts by direct method, using the Si/M = 50 molar ratio, in order to elucidate the way as the alkaline earth is incorporated on MCM-41 molecular sieve. The materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, nitrogen adsorption-desorption and theoretical calculations by DFT method. Experimental results and computer simulations showed that the alkaline earths were incorporated on MCM-41 through a complex structure, which negatively influences on basic sites formation.

  12. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

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

  13. Calcium channel blockers and Alzheimer's disease★

    OpenAIRE

    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...

  14. ISS Expedition 41 Press Kit

    Data.gov (United States)

    National Aeronautics and Space Administration — Press kit for ISS mission Expedition 41 from 05/2014-11/2014. Press kits contain information about each mission overview, crew, mission timeline, benefits, and...

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

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

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

  16. Electrophysical properties of calcium orthovanadate

    International Nuclear Information System (INIS)

    The electron conductivity, dielectric permeability and magnetic susceptibility of calcium orthovanadate are studied. It is shown that structural transformations bring about changes in the nature of electrophysical properties of Ca3(VO4)2 and cause the charge redistribution in VO43- anion groups

  17. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  18. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  19. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  20. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  1. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.5191 Section 582.5191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  2. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine,...

  3. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

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

  4. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  5. 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)...

  6. 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....

  7. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

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

    1999-01-01

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

  8. Virus and calcium: an unexpected tandem to optimize insecticide efficacy.

    Science.gov (United States)

    Apaire-Marchais, Véronique; Ogliastro, Mylène; Chandre, Fabrice; Pennetier, Cédric; Raymond, Valérie; Lapied, Bruno

    2016-04-01

    The effective control of insect pests is based on the rational use of the most efficient and safe insecticide treatments. To increase the effects of classical insecticides and to avoid the ability of certain pest insects to develop resistance, it is essential to propose novel strategies. Previous studies have shown that calcium-dependent phosphorylation/dephosphorylation is now considered as a new cellular mechanism for increasing the target sensitivity to insecticides. Because it is known that virus entry is correlated with intracellular calcium concentration rise, this report attempts to present the most important data relevant to the feasibility of combining an insect virus such as baculovirus or densovirus with an insecticide. In this case, the insect virus is not used as a bioinsecticide but acts as a synergistic agent able to trigger calcium rise and to activate calcium-dependent intracellular signalling pathways involved in the increase of the membrane receptors and/or ion channels sensitivity to insecticides. This virus-insecticide mixture represents a promising alternative to optimize the efficacy of insecticides against insect pests while reducing the doses. PMID:26743399

  9. The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential.

    Science.gov (United States)

    Zamponi, Gerald W; Striessnig, Joerg; Koschak, Alexandra; Dolphin, Annette C

    2015-10-01

    Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Ca(V)1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension. T-type (Ca(V)3) channels are a target of ethosuximide, widely used in absence epilepsy. The auxiliary subunit α2δ-1 is the therapeutic target of the gabapentinoid drugs, which are of value in certain epilepsies and chronic neuropathic pain. The limited use of intrathecal ziconotide, a peptide blocker of N-type (Ca(V)2.2) calcium channels, as a treatment of intractable pain, gives an indication that these channels represent excellent drug targets for various pain conditions. We describe how selectivity for different subtypes of calcium channels (e.g., Ca(V)1.2 and Ca(V)1.3 L-type channels) may be achieved in the future by exploiting differences between channel isoforms in terms of sequence and biophysical properties, variation in splicing in different target tissues, and differences in the properties of the target tissues themselves in terms of membrane potential or firing frequency. Thus, use-dependent blockers of the different isoforms could selectively block calcium channels in particular pathologies, such as nociceptive neurons in pain states or in epileptic brain circuits. Of important future potential are selective Ca(V)1.3 blockers for neuropsychiatric diseases, neuroprotection in Parkinson's disease, and resistant hypertension. In addition, selective or nonselective T-type channel blockers are considered potential therapeutic targets in epilepsy, pain, obesity, sleep

  10. Sodium/Calcium Exchangers Selectively Regulate Calcium Signaling in Mouse Taste Receptor Cells

    OpenAIRE

    Szebenyi, Steven A.; Laskowski, Agnieszka I.; Medler, Kathryn F.

    2010-01-01

    Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contrib...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    OpenAIRE

    Zenei Taira, Zenei

    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 ...

  13. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

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

    1998-01-01

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

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

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

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

  15. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  16. Calcium channel-dependent molecular maturation of photoreceptor synapses.

    Directory of Open Access Journals (Sweden)

    Nawal Zabouri

    Full Text Available Several studies have shown the importance of calcium channels in the development and/or maturation of synapses. The Ca(V1.4(α(1F knockout mouse is a unique model to study the role of calcium channels in photoreceptor synapse formation. It features abnormal ribbon synapses and aberrant cone morphology. We investigated the expression and targeting of several key elements of ribbon synapses and analyzed the cone morphology in the Ca(V1.4(α(1F knockout retina. Our data demonstrate that most abnormalities occur after eye opening. Indeed, scaffolding proteins such as Bassoon and RIM2 are properly targeted at first, but their expression and localization are not maintained in adulthood. This indicates that either calcium or the Ca(V1.4 channel, or both are necessary for the maintenance of their normal expression and distribution in photoreceptors. Other proteins, such as Veli3 and PSD-95, also display abnormal expression in rods prior to eye opening. Conversely, vesicle related proteins appear normal. Our data demonstrate that the Ca(V1.4 channel is important for maintaining scaffolding proteins in the ribbon synapse but less vital for proteins related to vesicular release. This study also confirms that in adult retinae, cones show developmental features such as sprouting and synaptogenesis. Overall we present evidence that in the absence of the Ca(V1.4 channel, photoreceptor synapses remain immature and are unable to stabilize.

  17. USING CALCIUM CARBONATE WHISKERS AS PAPERMAKING FILLER

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2011-05-01

    Full Text Available Whiskers, having large length/diameter ratio, are fiber-shaped single crystals. The technical possibility of using calcium carbonate whiskers as papermaking filler to replace conventional powder-like calcium carbonate was investigated. The results showed that it may be feasible to use calcium carbonate whisker as papermaking filler. Compared with conventional precipitated calcium carbonate, calcium carbonate whisker had higher retention efficiency. The use of calcium carbonate whisker also favorably affected the strength properties of paper sheets. A model was proposed to suggest the mechanism for paper strength improvement. The whiskers filled in paper sheets could increase the friction between fibers, thus increasing bonding strength. Moreover, the strength properties of paper were further improved because calcium carbonate whiskers were partly embedded in pulp fiber walls.

  18. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

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

  19. Molecular Interactions between Tarantula Toxins and Low-Voltage-Activated Calcium Channels

    OpenAIRE

    Autoosa Salari; Benjamin S. Vega; Milescu, Lorin S.; Mirela Milescu

    2016-01-01

    Few gating-modifier toxins have been reported to target low-voltage-activated (LVA) calcium channels, and the structural basis of toxin sensitivity remains incompletely understood. Studies of voltage-gated potassium (Kv) channels have identified the S3b–S4 “paddle motif,” which moves at the protein-lipid interface to drive channel opening, as the target for these amphipathic neurotoxins. Voltage-gated calcium (Cav) channels contain four homologous voltage sensor domains, suggesting multiple t...

  20. CERN: Fixed target targets

    International Nuclear Information System (INIS)

    Full text: While the immediate priority of CERN's research programme is to exploit to the full the world's largest accelerator, the LEP electron-positron collider and its concomitant LEP200 energy upgrade (January, page 1), CERN is also mindful of its long tradition of diversified research. Away from LEP and preparations for the LHC proton-proton collider to be built above LEP in the same 27-kilometre tunnel, CERN is also preparing for a new generation of heavy ion experiments using a new source, providing heavier ions (April 1992, page 8), with first physics expected next year. CERN's smallest accelerator, the LEAR Low Energy Antiproton Ring continues to cover a wide range of research topics, and saw a record number of hours of operation in 1992. The new ISOLDE on-line isotope separator was inaugurated last year (July, page 5) and physics is already underway. The remaining effort concentrates around fixed target experiments at the SPS synchrotron, which formed the main thrust of CERN's research during the late 1970s. With the SPS and LEAR now approaching middle age, their research future was extensively studied last year. Broadly, a vigorous SPS programme looks assured until at least the end of 1995. Decisions for the longer term future of the West Experimental Area of the SPS will have to take into account the heavy demand for test beams from work towards experiments at big colliders, both at CERN and elsewhere. The North Experimental Area is the scene of larger experiments with longer lead times. Several more years of LEAR exploitation are already in the pipeline, but for the longer term, the ambitious Superlear project for a superconducting ring (January 1992, page 7) did not catch on. Neutrino physics has a long tradition at CERN, and this continues with the preparations for two major projects, the Chorus and Nomad experiments (November 1991, page 7), to start next year in the West Area. Delicate neutrino oscillation effects could become

  1. Calcium sensitizers: What have we learned over the last 25 years?

    Science.gov (United States)

    Pollesello, P; Papp, Z; Papp, J Gy

    2016-01-15

    The use of inotropes for correcting hemodynamic dysfunction in patients with congestive heart failure has been described over many decades. Drugs such as cardiac glycosides, cathecolamines, phosphodiestherase inhibitors, and calcium sensitizers have been in turn proposed. However, the number of new chemical entities in this therapeutic field has been surprisingly low, and the current selection of drugs is limited. One of the paradigm shifts in the discovery for new inotropes was to focus on 'calcium sensitizers' instead of 'calcium mobilizers'. This was designed to lead to the development of safer inotropes, devoid of the complications that arise due to increased intracellular calcium levels. However, only three such calcium sensitizers have been fully developed over the latest 30 years. Moreover, two of these, levosimendan and pimobendan, have multiple molecular targets and other pharmacologic effects in addition to inotropy, such as peripheral vasodilation. More recently, omecamtiv mecarbil was described, which is believed to have a pure inotropy action that is devoid of pleiotropic effects. When the clinical data of these three calcium sensitizers are compared, it appears that the less pure inotropes have the cutting edge over the purer inotrope, due to additional effects during the treatment of a complex syndrome such as acute congested heart failure. This review aims to answer the question whether calcium sensitization per se is a sufficient strategy for bringing required clinical benefits to patients with heart failure. This review is dedicated to the memory of Heimo Haikala, a true and passionate innovator in this challenging field. PMID:26580334

  2. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

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

  3. 4 CFR 4.1 - Training.

    Science.gov (United States)

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Training. 4.1 Section 4.1 Accounts GOVERNMENT ACCOUNTABILITY OFFICE PERSONNEL SYSTEM EMPLOYEE PERFORMANCE AND UTILIZATION § 4.1 Training. The provisions of chapter 41, of title 5, United States Code, and Office of Personnel Management implementing...

  4. Sputter target

    Science.gov (United States)

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had...... higher urinary calcium excretion than female mice and their renal calcium transporters were expressed at a lower level. We also found that orchidectomized mice excreted less calcium in their urine than sham-operated control mice and that the hypocalciuria was normalized after testosterone replacement...... calcium transport. Thus, our study shows that gender differences in renal calcium handling are, in part, mediated by the inhibitory actions of androgens on TRPV5-mediated active renal calcium transport....

  6. Production Target Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-28

    The Northstar 99Mo production target, a cylindrical length of 100Mo rod, has evolved considerably since its first conception.  The cylinder was very early sliced into disks to increase the heat transfer area, first to 1 mm thick disks then to the current 0.5 mm thick.  The coolant was changed early in the target development from water to helium to eliminate corrosion and dissolution.  The diameter has increased from initially 6 mm to 12 mm, the current diameter of the test target now at ANL, to nominally 28 mm (26-30.6 mm, depending upon optimal beam spot size and shape).  The length has also changed to improve the production to cost ratio, so now the target is nominally 41 mm long (excluding coolant gaps between disks), and irradiated on both ends.  This report summarizes the current status of the plant target design.

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

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

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

  8. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

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

  9. Drying dichloromethane over calcium hydride

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of dichloromethane by a simple 10 step procedure. One can implement this protocol using common lab glass and lab equipment. First, dichloromethane is refluxed with calcium hydride to remove water. Then, dichloromethane is distilled to separate it from the byproducts of the reflux reaction. This procedure can be implemented in 1 day. ### Introduction In many instances i...

  10. Calmodulin-binding domains in Alzheimer's disease proteins: extending the calcium hypothesis.

    Science.gov (United States)

    O'Day, Danton H; Myre, Michael A

    2004-08-01

    The calcium hypothesis of Alzheimer's disease (AD) invokes the disruption of calcium signaling as the underlying cause of neuronal dysfunction and ultimately apoptosis. As a primary calcium signal transducer, calmodulin (CaM) responds to cytosolic calcium fluxes by binding to and regulating the activity of target CaM-binding proteins (CaMBPs). Ca(2+)-dependent CaMBPs primarily contain domains (CaMBDs) that can be classified into motifs based upon variations on the basic amphiphilic alpha-helix domain involving conserved hydrophobic residues at positions 1-10, 1-14 or 1-16. In contrast, an IQ or IQ-like domain often mediates Ca(2+)-independent CaM-binding. Based on these attributes, a search for CaMBDs reveals that many of the proteins intimately linked to AD may be calmodulin-binding proteins, opening new avenues for research on this devastating disease. PMID:15249195

  11. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

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

  12. Serotonin and calcium homeostasis during the transition period.

    Science.gov (United States)

    Weaver, S R; Laporta, J; Moore, S A E; Hernandez, L L

    2016-07-01

    The transition from pregnancy to lactation puts significant, sudden demands on maternal energy and calcium reserves. Although most mammals are able to effectively manage these metabolic adaptations, the lactating dairy cow is acutely susceptible to transition-related disorders because of the high amounts of milk being produced. Hypocalcemia is a common metabolic disorder that occurs at the onset of lactation. Hypocalcemia is also known to result in poor animal welfare conditions. In addition, cows that develop hypocalcemia are more susceptible to a host of other negative health outcomes. Different feeding tactics, including manipulating the dietary cation-anion difference and administering low-calcium diets, are commonly used preventative strategies. Despite these interventions, the incidence of hypocalcemia in the subclinical form is still as high as 25% to 30% in the United States dairy cow population, with a 5% to 10% incidence of clinical hypocalcemia. In addition, although there are various effective treatments in place, they are administered only after the cow has become noticeably ill, at which point there is already significant metabolic damage. This emphasizes the need for developing alternative prevention strategies, with the monoamine serotonin implicated as a potential therapeutic target. Our research in rodents has shown that serotonin is critical for the induction of mammary parathyroid hormone-related protein, which is necessary for the mobilization of bone tissue and subsequent restoration of maternal calcium stores during lactation. We have shown that circulating serotonin concentrations are positively correlated with serum total calcium on the first day of lactation in dairy cattle. Administration of serotonin's immediate precursor through feeding, injection, or infusion to various mammalian species has been shown to increase circulating serotonin concentrations, with positive effects on other components of maternal metabolism. Most recently

  13. The role of calcium in human aging.

    Science.gov (United States)

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  14. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (47Ca) 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 CaCO3. 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 47Ca. 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

  15. Characterization of HIV-1 envelope gp41 genetic diversity and functional domains following perinatal transmission

    Directory of Open Access Journals (Sweden)

    Davis Tiffany

    2006-07-01

    Full Text Available Abstract Background HIV-1 envelope gp41 is a transmembrane protein that promotes fusion of the virus with the plasma membrane of the host cells required for virus entry. In addition, gp41 is an important target for the immune response and development of antiviral and vaccine strategies, especially when targeting the highly variable envelope gp120 has not met with resounding success. Mutations in gp41 may affect HIV-1 entry, replication, pathogenesis, and transmission. We, therefore, characterized the molecular properties of gp41, including genetic diversity, functional motifs, and evolutionary dynamics from five mother-infant pairs following perinatal transmission. Results The gp41 open reading frame (ORF was maintained with a frequency of 84.17% in five mother-infant pairs' sequences following perinatal transmission. There was a low degree of viral heterogeneity and estimates of genetic diversity in gp41 sequences. Both mother and infant gp41 sequences were under positive selection pressure, as determined by ratios of non-synonymous to synonymous substitutions. Phylogenetic analysis of 157 mother-infant gp41 sequences revealed distinct clusters for each mother-infant pair, suggesting that the epidemiologically linked mother-infant pairs were evolutionarily closer to each other as compared with epidemiologically unlinked sequences. The functional domains of gp41, including fusion peptide, heptad repeats, glycosylation sites and lentiviral lytic peptides were mostly conserved in gp41 sequences analyzed in this study. The CTL recognition epitopes and motifs recognized by fusion inhibitors were also conserved in the five mother-infant pairs. Conclusion The maintenance of an intact envelope gp41 ORF with conserved functional domains and a low degree of genetic variability as well as positive selection pressure for adaptive evolution following perinatal transmission is consistent with an indispensable role of envelope gp41 in HIV-1 replication and

  16. STIM1 is a Calcium Sensor Specialized for Digital Signaling

    OpenAIRE

    Bird, Gary S.; Hwang, Sung-Yong; Smyth, Jeremy T.; Fukushima, Miwako; Boyles, Rebecca R.; Putney, James W.

    2009-01-01

    When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as representing a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occ...

  17. A study on hormonal control of calcium homeostasis in egyptian women

    International Nuclear Information System (INIS)

    This investigation was conducted to study the possible role of circulating hormones that regulate the calcium flux, in addition to serum levels of the inorganic mineral contents, calcium and phosphorus, on the pathogenesis of post-menopausal osteoporosis in egyptian women. The investigation studied also the response of these variables to both of estradiol withdrawal and age progress. Five groups of 11 postmenopausal osteoporotic (mean age 73 -+ 2.3 years), 26 postmenopausal women (mean age 56.2 -+ 2.4 years), 17 premenopausal women (mean age 48.8 -+ 0.7 years), 26 premenopausal women (mean age 41.5 -+ o.7 years) and 11 young adult premenopausal women(mean age 27.3 -+ 0.9 years) were recruited for this study. The post-peri- and pre- groups were further classified into subgroups according to their chronological age. Serum was assayed for parathyroid hormone (PTH), 25-hydroxyvitamin D, (25-OHD3), calcitonin (CT) total calcium (Ca), and inorganic phosphorus (ph), concentrations of estradiol (E2) in all subjects were also assayed for further correlation. The obtained data showed that the levels of hormones were not significantly changed among the different groups and subgroups leading to normal calcium homeostasis. PTH and total calcium were significantly correlated with both estrodial levels and chronological age

  18. Effect of calcium triphosphate cement on proximal humeral fracture osteosynthesis: a finite element analysis.

    Science.gov (United States)

    Kennedy, Jim; Feerick, Emer; McGarry, Patrick; FitzPatrick, David; Mullett, Hannan

    2013-08-01

    PURPOSE. To measure the effect of void-filling calcium triphosphate cement on the loads at the implant-bone interface of a proximal humeral fracture osteosynthesis using a finite element analysis. METHODS. Finite element models of a 3-part proximal humeral fracture fixed with a plate with and without calcium triphosphate cement augmentation were generated from a quantitative computed tomography dataset of an intact proximal humerus. Material properties were assigned to bone fragments using published expressions relating Young's modulus to local Hounsfield number. Boundary conditions were then applied to the model to replicate the physiological loads. The effect of void-filling calcium triphosphate cement was analysed. RESULTS. When the void was filled with calcium triphosphate cement, the pressure gradient of the bone surrounding the screws in the medial fracture fragment decreased 97% from up to 21.41 to 0.66 MPa. Peak pressure of the fracture planes decreased 95% from 6.10 to 0.30 MPa and occurred along the medial aspect. The mean stress in the screw locking mechanisms decreased 78% from 71.23 to 15.92 MPa. The angled proximal metaphyseal screw had the highest stress. CONCLUSION. Augmentation with calcium triphosphate cement improves initial stability and reduces stress on the implant-bone interface. PMID:24014777

  19. Sources of calcium in agonist-induced contraction of rat distal colon smooth muscle in vitro

    Institute of Scientific and Technical Information of China (English)

    Hua Zhou; De-Hu Kong; QunWan Pan; HaiHua Wang

    2008-01-01

    AIM:To study the origin of calcium necessary foragonist-induced contraction of the distal colon in rats.METHODS:The change in intracellular calcium concentration ([Ca2+]i)evoked by elevating external Ca2+was detected by fura 2/AM fluorescence.Contractile activity was measured with a force displacement transducer.Tension was continuously monitored and recorded using a Powerlab 4/25T data acquisition system with an ML110 bridge bioelectric physiographic amplifier.RESULTS:Store depletion induced Ca2+ influx had an effect on [Ca2+]i.In nominally Ca2+-free medium,the sarco-endoplasmic reticulum Ca2+-ATPase inhibitor thapsigargin (1 μmol/L) increased [Ca2+]i from 68 to 241 nmol/L,and to 458 (P<0.01) and 1006 nmol/L (P<0.01),respectively,when 1.5 mmol/L and 3.0 mmol/L extracellular Ca2+ was reintroduced.Furthermore,the change in [Ca2+]1.was observed with verapamil (5 μmol/L),La3+(1 mmol/L) or KCI (40 mmol/L) in the bathing solution.These channels were sensitive to La3+(P<0.01),insensitive to verapamil,and voltage independent.In isolated distal colons we found that in normal Krebs solution,contraction induced by acetylcholine (ACh) was partially inhibited by verapamil,and the inhibitory rate was 41% (P<0.05).On the other hand,in Ca2+-free Krebs solution,ACh induced transient contraction due to Ca2+ release from the inLracellular stores.The transient contraction lasted until the Ca2+ store was depleted.Restoration of extracellular Ca2+ in the presence of atropine produced contraction,mainly due to Ca2+ influx.Such contraction was not inhibited by verapamil,but was decreased by La3+ (50 μmol/L) from 0.96 to 0.72 g (P<0.01).CONCLUSION:The predominant source of activator Ca2+ for the contractile response to agonist is extracellular Ca2+,and intracellular Caz+ has little role to play in mediating excitation-contraction coupling by agonists in rat distal colon smooth muscle in vitro.The influx of extracellular Ca2+ is mainly mediated through voltage-,receptor- and

  20. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    Science.gov (United States)

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (Ptortillas or those fortified with calcium carbonate was preferred over the control (Ptortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  1. 41st Aerospace Mechanisms Symposium

    Science.gov (United States)

    Boesiger, Edward A. (Editor)

    2012-01-01

    The proceedings of the 41st Aerospace Mechanisms Symposium are reported. JPL hosted the conference, which was held in Pasadena Hilton, Pasadena, California on May 16-18, 2012. Lockheed Martin Space Systems cosponsored the symposium. Technology areas covered include gimbals and positioning mechanisms, components such as hinges and motors, CubeSats, tribology, and Mars Science Laboratory mechanisms.

  2. Target capture and target ghosts

    Science.gov (United States)

    Auerbach, Steven P.

    1996-05-01

    Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.

  3. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

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

    2009-05-21

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

  4. Biphasic calcium phosphate in periapical surgery

    OpenAIRE

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

    2008-01-01

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

  5. Gravity, Calcium, And Bone: Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1992-01-01

    Report reviews short-term flight and ground-based experiments on effects of 1 g and 0 g on skeletal adaptation, calcium metabolism, and growth processes. Results indicate two principal components of calcium metabolism-calcium endocrine system and bone - respond within days to changes in orientation of body in gravitation and to weightlessness. Effects of spaceflight or bed rest on biomechanics of bones more severe than on total body bone mass.

  6. Gravity, calcium, and bone - Update, 1989

    Science.gov (United States)

    Arnaud, Sara B.; Morey-Holton, Emily

    1990-01-01

    Recent results obtained on skeletal adaptation, calcium metabolism, and bone browth during short-term flights and ground simulated-microgravity experiments are presented. Results demonstrate that two principal components of calcium metabolism respond within days to changes in body position and to weightlessness: the calcium endocrine system and bone characteristics. Furthermore, results of recent studies imply that bone biomechanics are more severely affected by spaceflight exposures than is the bone mass.

  7. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim

    2014-01-01

    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results in...... FHH, while in homozygous patients as well as in compound heterozygous or dominant negative heterozygous patients, it may result in neonatal severe hyperparathyroidism (NSHPT). Parathyroid surgery is not indicated in FHH and does not lower plasma calcium unless total parathyroidectomy is performed, in...

  8. Overbased Calcium sulfonate Detergent Technology Overview

    Institute of Scientific and Technical Information of China (English)

    MA Qing-gao; MUIR Ronald J.

    2009-01-01

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

  9. Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    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(/sup 44/Ca//sup 40/Ca) = 11 x 10 /sup -4/ and epsilon(/sup 48/Ca//sup 40/Ca) = 18 x 10/sup -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/sup -4/. 20 references, 2 figures.

  10. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

    Data on calcium carboorthovanadate, Ca10(VO4)6CO3, 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 (CO3)2- and orthovanadate (VO4)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

  11. Calcium supplements: do they help or harm?

    Science.gov (United States)

    Manson, Joann E; Bassuk, Shari S

    2014-01-01

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

  12. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

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

    2010-01-01

    appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1 s...... affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be...

  13. Peroxisome is a reservoir of intracellular calcium.

    Science.gov (United States)

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

    2006-07-01

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

  14. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    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....

  15. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca2+ (1.1 Angstrom) compared to Mg2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

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

    OpenAIRE

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

    2009-01-01

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

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

    OpenAIRE

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

    2015-01-01

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

  18. Drosophila mushroom body Kenyon cells generate spontaneous calcium transients mediated by PLTX-sensitive calcium channels.

    OpenAIRE

    Jiang, Shaojuan Amy; Campusano, Jorge M.; Su, Hailing; O'Dowd, Diane K.

    2005-01-01

    Spontaneous calcium oscillations in mushroom bodies of late stage pupal and adult Drosophila brains have been implicated in memory consolidation during olfactory associative learning. This study explores the cellular mechanisms regulating calcium dynamics in Kenyon cells, principal neurons in mushroom bodies. Fura-2 imaging shows that Kenyon cells cultured from late stage Drosophila pupae generate spontaneous calcium transients in a cell autonomous fashion, at a frequency similar to calcium o...

  19. The Electronic Structure of Calcium

    DEFF Research Database (Denmark)

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

    1981-01-01

    The electronic structure of calcium under pressure is re-examined by means of self-consistent energy band calculations based on the local density approximation and using the linear muffin-tin orbitals (LMTO) method with corrections to the atomic sphere approximation included. At zero pressure.......149 Ryd, respectively, relative to the s band, give the best possible agreement. Under increasing pressure the s and p electrons are found to transfer into the d band, and Ca undergoes metal-semimetal-metal electronic transitions. Calculations of the bandstructure and the electronic pressure, including...

  20. Physicochemical investigation of calcium bromtechnetate

    International Nuclear Information System (INIS)

    Calcium hexabromotechnetate is extracted for the first time and its composition corresponding to the CaTcBr6 formula is determined. Using the thermal analysis method the anhydrous salt stability boundaries are found. The X-ray phase analysis has shown the compound to be isostructural with (NH4)2TcI6 and has a rhombic b.c.c. crystal lattice with the following parameters: a=10.39+-0.01, b=7.34+-0.01 and c=7.45+-0.001A. At 380-420 deg C CaTcBr6 decomposes to Tc, CaBr2 and Br

  1. Calcium Imaging Perspectives in Plants

    Directory of Open Access Journals (Sweden)

    Chidananda Nagamangala Kanchiswamy

    2014-03-01

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

  2. Barium calcium hydroxyapatite solid solutions

    International Nuclear Information System (INIS)

    The replacement of calcium by barium in the hydroxyapatite structure by solid-state reaction at different temperatures and by precipitation from an aqueous system has been investigated by X-ray diffraction and i.r. absorption analyses. The products obtained by solid-state reaction at 1200 deg C are solid solutions over the range of barium concentration 60 to 100 atom %. The lattice dimensions and the i.r. frequencies of the solid solutions vary linearly with the atom % of barium. Only small amounts of barium can be incorporated in hydroxyapatite by precipitation from the aqueous system. (author)

  3. Calcium

    Science.gov (United States)

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

  4. Calcium

    Science.gov (United States)

    ... eliminates in urine, feces, and sweat. These include consumption of alcohol- and caffeine-containing beverages as well as intake ... and older 2,000 mg Pregnant and breastfeeding teens 3,000 mg Pregnant and breastfeeding adults 2, ...

  5. Store-operated calcium channels and pro-inflammatory signals

    Institute of Scientific and Technical Information of China (English)

    Wei-chiao CHANG

    2006-01-01

    In non-excitable cells such as T lymphocytes,hepatocytes,mast cells,endothelia and epithelia,the major pathway for calcium(Ca2+)entry is through store-operated Ca2+ channels in the plasma membrane.These channels are activated by the emptying of intracellular Ca2+ stores,however,neither the gating mechanism nor the downstream targets of these channels has been clear established.Here,I review some of the proposed gating mechanisms of store-operated Ca2+ channels and the functional implications in regulating pro-inflammatory signals.

  6. ANTIHYPERTENSIVE TREATMENT IN ELDERLY PATIENTS WITH DIHYDROPYRIDINE CALCIUM ANTAGONISTS

    Directory of Open Access Journals (Sweden)

    Y. A. Karpov

    2016-01-01

    Full Text Available The proofs of necessity of active arterial hypertension (AH treatment in elderly patients are given. Peculiarities of pathogenesis of AH in elderly patients, connected predominantly with loss of big arteries elasticity and reasoning widely spread of isolated systolic AH in these patients, are discussed. Advantages of dihydropyridine calcium antagonists (DPCA for AH treatment in elderly patients are proved, safety of treatment with DPCA is discussed. Data of clinical studies is analyzed. Analysis of target levels of blood pressure for antihypertensive treatment in elderly hypertensive patients is made. As a conclusion DPCA are the medicines of choice for AH treatment in elderly patients.

  7. The Calcium Triplet metallicity calibration for galactic bulge stars

    CERN Document Server

    Vasquez, S; Hill, V; Gonzalez, O A; Saviane, I; Rejkuba, M; Battaglia, G

    2015-01-01

    We present a new calibration of the Calcium II Triplet equivalent widths versus [Fe/H], constructed upon K giant stars in the Galactic bulge. This calibration will be used to derive iron abundances for the targets of the GIBS survey, and in general it is especially suited for solar and supersolar metallicity giants, typical of external massive galaxies. About 150 bulge K giants were observed with the GIRAFFE spectrograph at VLT, both at resolution R~20,000 and at R~6,000. In the first case, the spectra allowed us to perform direct determination of Fe abundances from several unblended Fe lines, deriving what we call here high resolution [Fe/H] measurements. The low resolution spectra allowed us to measure equivalent widths of the two strongest lines of the near infrared Calcium II triplet at 8542 and 8662 A. By comparing the two measurements we derived a relation between Calcium equivalent widths and [Fe/H] that is linear over the metallicity range probed here, -1<[Fe/H]<+0.7. By adding a small second or...

  8. Effect of calcium on adsorption capacity of powdered activated carbon.

    Science.gov (United States)

    Li, Gang; Shang, Junteng; Wang, Ying; Li, Yansheng; Gao, Hong

    2013-12-01

    We investigated the effect of calcium ion on the adsorption of humic acid (HA) (as a target pollutant) by powered activated carbon. The HA adsorption isotherms at different pH and kinetics of two different solutions including HA alone and HA doped Ca(2+), were performed. It was showed that the adsorption capacity of powdered activated carbon (PAC) for HA was markedly enhanced when Ca(2+) was doped into HA. Also, HA and Ca(2+) taken as nitrate were tested on the uptake of each other respectively and it was showed that the adsorbed amounts of both of them were significantly promoted when HA and calcium co-existed. Furthermore, the adsorbed amount of HA slightly decreased with the increasing of Ca(2+) concentration, whereas the amount of calcium increased with the increasing of HA concentration, but all above the amounts without addition. Finally, the change of pH before and after adsorption process is studied. In the two different solutions including HA alone and HA doped Ca(2+), pH had a small rise, but the extent of pH of later solution was bigger. PMID:25078809

  9. Translocation and bonding of calcium (45Ca) in two-year-old seedlings of spruce (Picea abies[L.] Karst.) and pine (Pinus sylvestris L.)

    International Nuclear Information System (INIS)

    Within the framework of the project ''Effect of liming and magnesium fertilization on the uptake, transport, and chemical bonding form of calcium and magnesium in conifers'', experiments regarding the calcium budget of two-year-old spruce and pine seedlings under conditions of controlled nutrition in a gravel culture were carried out. Two variants of calcium nutrition demonstrated which of the mechanisms in the calcium metabolism of trees are dependent on changes in element availability. Root labelling using the radioactive tracer 45Ca permitted aimed investigation of the uptake and translocation of calcium during shoot formation in May. The functional importance of the investigated nutritive element was characterized by breaking up the total calcium contents (45Ca) into the three essential chemical bonding forms (water-soluble Ca, Ca-pectate, Ca-oxalate) for the different tree fractions.- The culture experiments led to the conclusion that the root tips are most important as sites of calcium uptake. Translocation within the roots to the shoot took place via diffusion and exchange displacement as a function of calcium supply in the nutritive solution. There is no clue to support the assumption of a regulation of calcium uptake in spruces; in pines, by contrast, it cannot be excluded.- From a nutrition-physiological viewpoint, a total calcium content of 2 mg per gramme of dry mass is to be considered as sufficient. As this target is always attained, even where calcium supply is scarce, it is not appropriate to equate increased calcium availability with enhanced nutrient supply. Rather, the results discussed seem to support the theory that the trees now need to detoxicate excessively high calcium concentrations, which are liable to endanger the physiological cell metabolism, by a reaction with oxalic acid resulting in the formation of calcium oxalate. (orig.)

  10. Functional and pharmacological consequences of the distribution of voltage-gated calcium channels in the renal blood vessels

    DEFF Research Database (Denmark)

    Hansen, P B L

    2013-01-01

    usually associated with vascular contractility. However, the L-, T- and P-/Q-types of calcium channels are present in the renal vasculature and are differentially involved in controlling vascular contractility, thereby contributing to regulation of kidney function and blood pressure. In the preglomerular...... to preferential efferent vasodilation, reduction of glomerular pressure and proteinuria. Therefore, renovascular T-type channels might provide novel therapeutic targets, and may have superior renoprotective effects compared to conventional calcium blockers....

  11. Elevated Intracellular Calcium Increases Ferritin H Expression Through an NFAT-Independent Posttranscriptional Mechanism Involving mRNA Stabilization

    OpenAIRE

    MacKenzie, Elizabeth L.; Tsuji, Yoshiaki

    2008-01-01

    An increase in intracellular Ca2+ is one of the initiating events in T cell activation. A calcium-mediated signaling cascade in T cells involves activation of calcineurin and the dephosphorylation and translocation of Nuclear Factor of Activated T-cells (NFAT), resulting in the transcriptional activation of target genes such as IL-2. In the present study, we found that increased intracellular calcium leads to induction of the antioxidant protein ferritin H. We previously reported that the fer...

  12. Differential regulation of calcium signalling pathways by components of Piper methysticum (‘Awa)

    Science.gov (United States)

    Shimoda, L.M.N; Showman, A.; Baker, J.D.; Lange, I.; Koomoa, D.L.; Stokes, A.J.; Borris, R.P.; Turner, H.

    2015-01-01

    Kava is a soporific, anxiolytic and relaxant in widespread ritual and recreational use throughout the Pacific. Traditional uses of kava by indigenous Pacific Island peoples reflect a complex pharmacopeia, centered on GABA-ergic effects of the well-characterized kavalactones. However, peripheral effects of kava suggest active components other than the CNS-targeted kavalactones. We have previously shown that immunocytes exhibit calcium mobilization in response to traditionally-prepared kava extracts, and that the kavalactones do not induce these calcium responses. Here, we characterize the complex calcium-mobilizing activity of traditionally-prepared and partially HPLC-purified kava extracts, noting induction of both calcium entry and store release pathways. Kava components activate intracellular store depletion of thapsigargin-sensitive and –insensitive stores that are coupled to the calcium release activated (CRAC) current, and cause calcium entry through non-store-operated pathways. Together with the pepper-like potency reported by kava users, these studies lead us to hypothesize that kava extracts contain one or more ligands for the transient receptor potential (TRP) family of ion channels. Indeed, TRP-like conductances are observed in kava-treated cells under patch clamp. Thus TRP-mediated cellular effects may be responsible for some of the reported pharmacology of kava. PMID:25640812

  13. Comparison of radioisotopic studied calcium metabolism in the orally administered and inhaled cadmium rat

    International Nuclear Information System (INIS)

    The radioisotopic study of calcium metabolism in the rat after oral administration of cadmium, 8 mg/kg during 13 weeks, has shown two different effects of this ion: 1) in the intestine, cadmium inhibits the absorption of calcium by active transport; 2) in the deep bone compartment, the decrease of the bone calcium used for the crystallization and slowly exchangeable with the calcium central pool (serum, extracellular and soft tissues calcium) is combined with a reduction of the exchange rates between the two compartments. When administered through a microparticle aerosol inhalation (1 mg/m3 of air, 30 mn a day, during 12 weeks), cadmium's main target organ is the deep bone compartment. For both modes of administration, the slowing down of osteogenesis is confirmed by a drop in serum alkaline phosphatase after a four weeks period which reflects a decrease of the osteoblastic activity. Therefore it appears that the effects on bones observed during the chronic oral cadmium administration, do not result from a malabsorption of intestine calcium but also from the very action the Cd++ ion on the bone crystallization process

  14. Plasma membrane calcium ATPase proteins as novel regulators of signal transduction pathways

    Institute of Scientific and Technical Information of China (English)

    Mary; Louisa; Holton; Michael; Emerson; Ludwig; Neyses; Angel; L; Armesilla

    2010-01-01

    Emerging evidence suggests that plasma membrane calcium ATPases (PMCAs) play a key role as regulators of calcium-triggered signal transduction pathways via interaction with partner proteins. PMCAs regulate these pathways by targeting specific proteins to cellular sub-domains where the levels of intracellular freecalcium are kept low by the calcium ejection properties of PMCAs. According to this model, PMCAs have been shown to interact functionally with the calcium-sensitive proteins neuronal nitric oxide synthase, calmodulindependent serine protein kinase, calcineurin and endothelial nitric oxidase synthase. Transgenic animals with altered expression of PMCAs are being used to evaluate the physiological significance of these interactions. To date, PMCA interactions with calcium-dependent partner proteins have been demonstrated to play a crucial role in the pathophysiology of the cardiovascular system via regulation of the nitric oxide and calcineurin/nuclear factor of activated T cells pathways. This new evidence suggests that PMCAs play a more sophisticated role than the mere ejection of calcium from the cells, by acting as modulators of signaling transduction pathways.

  15. Calcium and Vitamin D: Important at Every Age

    Science.gov (United States)

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

  16. Clinical validation of dialysable calcium in relation to other methods of serum calcium measurement.

    OpenAIRE

    Prince, R. L.; Langton, S R

    1985-01-01

    Dialysable calcium (CaD) values were measured by a simple technique not interfered with by protein bound calcium and validation attempted by comparison with concentrations of ionised calcium (CaI) and clinical categorisation. CaD values were also compared with total calcium (CaT) and albumin adjusted calcium (CaA) concentrations. The normal ranges for CaD, CaT, CaA, and CaI were calculated from the results in healthy blood donors. In 50 normal subjects CaD was more highly correlated with CaI ...

  17. An Intracellular Calcium Oscillations Model Including Mitochondrial Calcium Cycling

    Institute of Scientific and Technical Information of China (English)

    SHI Xiao-Min; LIU Zeng-Rong

    2005-01-01

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

  18. Low-energy electron scattering from calcium

    International Nuclear Information System (INIS)

    Full text: The B-spline R-matrix method (BSR) is used to investigate the integrated cross sections (ICS) of elastic electron scattering from neutral calcium in the ultra-low energy range from threshold to 0.5 eV. The close-coupling expansion includes 39 bound states of neutral calcium, covering all states from the ground state to 4s8s 1S. The computational model was described in detail. Briefly, we generate an accurate target description by using multiconfiguration expansions, accounting for both valence and core-valence correlations. Very importantly, we use term-dependent valence orbitals, which are optimized individually for the various states of interest. We also account for relaxation of the core orbitals, due to the deep penetration of the 3d orbital. As a result, we have a set of normalized orthogonal one-electron orbitals for each state, but the orbitals from different sets do not form an orthonormal basis. In this work we compared the total and partial electron-impact cross sections from Ca in the ultra-low energy region, calculated in two different R-matrix approaches: the present BSR method and R-matrix with pseudostates method (RMPS). As seen from our calculations, basic difference between the cross sections in two R-matrix approaches comes mainly from the dominated 2Po partial wave. In the same time, partial cross sections for the 2Se and 2De partial waves in these two methods practically coincide. In the present work we also have compared the total BSR39 and RMPS cross sections with experimental data of Romaniuk et al.. Overall, the agreement between both R-matrix (BSR39 and RMPS) results and the experimental data is satisfactory, although a few discrepancies remain. We have compared 2Se, 2Po and 2De partial eigen-phases of electron-impact scattering from Ca at low energies region between most recent calculations: BSR39 (the present calculation), RMPS and the method of static-exchange formalism. Again, the largest discrepancy between different methods

  19. Bone Up on the Need for Calcium.

    Science.gov (United States)

    Mann, Peggy

    1987-01-01

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

  20. 21 CFR 182.8217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  1. 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.

  2. Calcium Free Asbestos for Fuel Cells

    Science.gov (United States)

    Snitzer, B. A.

    1983-01-01

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

  3. Stochastic models of intracellular calcium signals

    International Nuclear Information System (INIS)

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

  4. Stochastic Kinetics of Intracellular Calcium Oscillations

    Institute of Scientific and Technical Information of China (English)

    陈昌胜; 曾仁端

    2003-01-01

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

  5. 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 CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium...

  6. Engineering calcium oxalate crystal formation in Arabidopsis

    Science.gov (United States)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  7. Stochastic models of intracellular calcium signals

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-10

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

  8. Particularities of thermal expansion of calcium vanadates

    International Nuclear Information System (INIS)

    Temperature dependence of unit cell parameters of calcium vanadates Ca(VO3)2, Ca2V2O7 and Ca3(VO4)2 is studied. It is shown that lattice parameters of meta- and pyrovanadates change monotonously. Lattice parameters of calcium orthovanadate change sharply and unmonotonously at 400-500 deg C

  9. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

    ALG-2 was originally discovered as a pro-apoptotic protein in a genetic screen. Due to its ability to bind calcium with high affinity it was postulated to provide a link between the known effect of calcium in programmed cell death and the molecular death execution machinery. This review article...

  11. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  12. Alpha-1 giardin is an annexin with highly unusual calcium-regulated mechanisms.

    Science.gov (United States)

    Weeratunga, Saroja K; Osman, Asiah; Hu, Nien-Jen; Wang, Conan K; Mason, Lyndel; Svärd, Staffan; Hope, Greg; Jones, Malcolm K; Hofmann, Andreas

    2012-10-19

    Alpha-giardins constitute the annexin proteome (group E annexins) in the intestinal protozoan parasite Giardia and, as such, represent the evolutionary oldest eukaryotic annexins. The dominance of alpha-giardins in the cytoskeleton of Giardia with its greatly reduced actin content emphasises the importance of the alpha-giardins for the structural integrity of the parasite, which is particularly critical in the transformation stage between cyst and trophozoite. In this study, we report the crystal structures of the apo- and calcium-bound forms of α1-giardin, a protein localised to the plasma membrane of Giardia trophozoites that has recently been identified as a vaccine target. The calcium-bound crystal structure of α1-giardin revealed the presence of a type III site in the first repeat as known from other annexin structures, as well as a novel calcium binding site situated between repeats I and IV. By means of comparison, the crystal structures of three different alpha-giardins known to date indicate that these proteins engage different calcium coordination schemes, among each other, as well as compared to annexins of groups A-D. Evaluation of the calcium-dependent binding to acidic phosphoplipid membranes revealed that this process is not only mediated but also regulated by the environmental calcium concentration. Uniquely within the large family of annexins, α1-giardin disengages from the phospholipid membrane at high calcium concentrations possibly due to formation of a dimeric species. The observed behaviour is in line with changing calcium levels experienced by the parasite during excystation and may thus provide first insights into the molecular mechanisms underpinning the transformation and survival of the parasite in the host. PMID:22796298

  13. MicroRNA-30 family members regulate calcium/calcineurin signaling in podocytes

    Science.gov (United States)

    Wu, Junnan; Zheng, Chunxia; Wang, Xiao; Yun, Shifeng; Zhao, Yue; Liu, Lin; Lu, Yuqiu; Ye, Yuting; Zhu, Xiaodong; Zhang, Changming; Shi, Shaolin; Liu, Zhihong

    2015-01-01

    Calcium/calcineurin signaling is critical for normal cellular physiology. Abnormalities in this pathway cause many diseases, including podocytopathy; therefore, understanding the mechanisms that underlie the regulation of calcium/calcineurin signaling is essential. Here, we showed that critical components of calcium/calcineurin signaling, including TRPC6, PPP3CA, PPP3CB, PPP3R1, and NFATC3, are the targets of the microRNA-30 family (miR-30s). We found that these 5 genes are highly expressed as mRNA, but the level of the proteins is low in normal podocytes. Conversely, protein levels were markedly elevated in podocytes from rats treated with puromycin aminonucleoside (PAN) and from patients with focal segmental glomerulosclerosis (FSGS). In both FSGS patients and PAN-treated rats, miR-30s were downregulated in podocytes. In cultured podocytes, PAN or a miR-30 sponge increased TRPC6, PPP3CA, PPP3CB, PPP3R1, and NFATC3 expression; calcium influx; intracellular Ca2+ concentration; and calcineurin activity. Moreover, NFATC3 nuclear translocation, synaptopodin degradation, integrin β3 (ITGB3) activation, and actin fiber loss, which are downstream of calcium/calcineurin signaling, were induced by miR-30 reduction but blocked by the calcineurin inhibitor FK506. Podocyte-specific expression of the miR-30 sponge in mice increased calcium/calcineurin pathway component protein expression and calcineurin activity. The mice developed podocyte foot process effacement and proteinuria, which were prevented by FK506. miR-30s also regulated calcium/calcineurin signaling in cardiomyocytes. Together, our results identify miR-30s as essential regulators of calcium/calcineurin signaling. PMID:26436650

  14. 28 CFR 2.41 - Travel approval.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Travel approval. 2.41 Section 2.41..., YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.41 Travel approval. (a) The probation officer may approve travel outside the district without approval of...

  15. 46 CFR 356.41 - Management agreements.

    Science.gov (United States)

    2010-10-01

    ... which the management company provides marketing services, consulting services or other services that are... 46 Shipping 8 2010-10-01 2010-10-01 false Management agreements. 356.41 Section 356.41 Shipping..., Management Agreements and Exclusive or Long-Term Contracts § 356.41 Management agreements. (a) An owner...

  16. 43 CFR 41.405 - Housing.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Housing. 41.405 Section 41.405 Public... in Education Programs or Activities Prohibited § 41.405 Housing. (a) Generally. A recipient shall not... offer different services or benefits related to housing, except as provided in this section...

  17. 7 CFR 993.41 - Marketing policy.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Marketing policy. 993.41 Section 993.41 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Marketing Policy § 993.41 Marketing policy. (a) On or before the first...

  18. 7 CFR 1215.41 - Contracts.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Contracts. 1215.41 Section 1215.41 Agriculture..., Consumer Information, and Industry Information § 1215.41 Contracts. The Board shall not contract with any... and approved by the Secretary. Any contract or agreement shall provide that: (a) The contractor...

  19. 43 CFR 41.500 - Employment.

    Science.gov (United States)

    2010-10-01

    ... in Employment in Education Programs or Activities Prohibited § 41.500 Employment. (a) General. (1) No... Federal financial assistance. (2) A recipient shall make all employment decisions in any education program... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Employment. 41.500 Section 41.500...

  20. 45 CFR 92.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Financial reporting. 92.41 Section 92.41 Public... Reports, Records Retention, and Enforcement § 92.41 Financial reporting. (a) General. (1) Except as... authorized by OMB, for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  1. 21 CFR 1403.41 - Financial reporting.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Financial reporting. 1403.41 Section 1403.41 Food... Enforcement § 1403.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  2. 29 CFR 97.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Financial reporting. 97.41 Section 97.41 Labor Office of the... LOCAL GOVERNMENTS Post-Award Requirements Reports, Records Retention, and Enforcement § 97.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a)(2) and (5) of this section, grantees...

  3. 34 CFR 80.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Financial reporting. 80.41 Section 80.41 Education... Enforcement § 80.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  4. 45 CFR 602.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Financial reporting. 602.41 Section 602.41 Public... Requirements § 602.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  5. 32 CFR 33.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Financial reporting. 33.41 Section 33.41... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.41 Financial reporting... forms as may from time to time be authorized by OMB, for: (i) Submitting financial reports to...

  6. 45 CFR 1157.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Financial reporting. 1157.41 Section 1157.41... Enforcement § 1157.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  7. 49 CFR 18.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Financial reporting. 18.41 Section 18.41... Enforcement § 18.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  8. 22 CFR 135.41 - Financial reporting.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Financial reporting. 135.41 Section 135.41... Enforcement § 135.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  9. 28 CFR 66.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Financial reporting. 66.41 Section 66.41..., Retention, and Enforcement § 66.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a..., for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  10. 29 CFR 1470.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Financial reporting. 1470.41 Section 1470.41 Labor... Reports, Records Retention, and Enforcement § 1470.41 Financial reporting. (a) General. (1) Except as... authorized by OMB, for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  11. 45 CFR 1174.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Financial reporting. 1174.41 Section 1174.41... Enforcement § 1174.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  12. 45 CFR 1183.41 - Financial reporting.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Financial reporting. 1183.41 Section 1183.41... Enforcement § 1183.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a)(2) and (5) of...) Submitting financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when...

  13. 20 CFR 437.41 - Financial reporting.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Financial reporting. 437.41 Section 437.41... Enforcement § 437.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a)(2) and (5) of...) Submitting financial reports to SSA, or (ii) Requesting advances or reimbursements when letters of credit...

  14. 30 CFR 36.41 - Testing methods.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Testing methods. 36.41 Section 36.41 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF... Requirements § 36.41 Testing methods. Mobile diesel-powered transportation equipment submitted...

  15. 39 CFR 3060.41 - Supporting documentation.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Supporting documentation. 3060.41 Section 3060.41 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL ACCOUNTING PRACTICES AND TAX RULES FOR THE THEORETICAL COMPETITIVE PRODUCTS ENTERPRISE § 3060.41 Supporting documentation. (a) In support of...

  16. 14 CFR 137.41 - Personnel.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Personnel. 137.41 Section 137.41 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS... Operating Rules § 137.41 Personnel. (a) Information. The holder of an agricultural aircraft...

  17. 43 CFR 41.310 - Recruitment.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Recruitment. 41.310 Section 41.310 Public... in Admission and Recruitment Prohibited § 41.310 Recruitment. (a) Nondiscriminatory recruitment. A... recruitment and admission of students. A recipient may be required to undertake additional recruitment...

  18. 43 CFR 41.510 - Recruitment.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Recruitment. 41.510 Section 41.510 Public... in Employment in Education Programs or Activities Prohibited § 41.510 Recruitment. (a) Nondiscriminatory recruitment and hiring. A recipient shall not discriminate on the basis of sex in the...

  19. 19 CFR 12.41 - Prohibited films.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Prohibited films. 12.41 Section 12.41 Customs... SPECIAL CLASSES OF MERCHANDISE Immoral Articles § 12.41 Prohibited films. (a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any...

  20. 29 CFR 1912.41 - Legal services.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Legal services. 1912.41 Section 1912.41 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADVISORY COMMITTEES ON STANDARDS Miscellaneous § 1912.41 Legal services. The Solicitor of Labor...

  1. 27 CFR 41.112 - Tax return.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Tax return. 41.112 Section 41.112 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF... States Deferred Payment of Tax in Puerto Rico on Tobacco Products § 41.112 Tax return. The...

  2. 15 CFR 265.41 - Gambling.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Gambling. 265.41 Section 265.41..., GAITHERSBURG, MARYLAND, AND BOULDER AND FORT COLLINS, COLORADO Buildings and Grounds § 265.41 Gambling. No... gambling devices, the conduct of lotteries or pools, or in the selling or purchasing of numbers tickets,...

  3. 32 CFR 2103.41 - Reproduction controls.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Reproduction controls. 2103.41 Section 2103.41... Safeguarding § 2103.41 Reproduction controls. The Staff Secretary shall maintain records to show the number and... dissemination or reproduction limitations....

  4. 42 CFR 35.41 - Inventory.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inventory. 35.41 Section 35.41 Public Health PUBLIC... STATION MANAGEMENT Disposal of Money and Effects of Deceased Patients § 35.41 Inventory. Promptly after the death of a patient in a station or hospital of the Service, an inventory of his money and...

  5. 22 CFR 41.71 - Transit aliens.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Transit aliens. 41.71 Section 41.71 Foreign... NATIONALITY ACT, AS AMENDED Transit Aliens § 41.71 Transit aliens. (a) Transit aliens—general. An alien is classifiable as a nonimmigrant transit alien under INA 101(a) (15) (C) if the consular officer is...

  6. 22 CFR 41.108 - Medical examination.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Medical examination. 41.108 Section 41.108... AND NATIONALITY ACT, AS AMENDED Application for Nonimmigrant Visa § 41.108 Medical examination. (a) Requirements for medical examination. An applicant for a nonimmigrant visa shall be required to take a...

  7. 27 CFR 4.1 - General.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false General. 4.1 Section 4.1 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE Scope § 4.1 General. The regulations in this part...

  8. 14 CFR 431.41 - Communications plan.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Communications plan. 431.41 Section 431.41... Launch and Reentry of a Reusable Launch Vehicle § 431.41 Communications plan. (a) An applicant shall submit a plan providing vehicle safety operations personnel communications procedures during the...

  9. 43 CFR 41.525 - Fringe benefits.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical,...

  10. 24 CFR 206.41 - Counseling.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Counseling. 206.41 Section 206.41... CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Mortgagors § 206.41 Counseling. (a) List... receive counseling. (b) Information to be provided. A counselor must discuss with the mortgagor: (1)...

  11. 22 CFR 221.41 - Arbitration.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Arbitration. 221.41 Section 221.41 Foreign... Administration § 221.41 Arbitration. Any controversy or claim between A.I.D. and any noteholder arising out of this Guarantee shall be settled by arbitration to be held in Washington, DC in accordance with the...

  12. 22 CFR 204.41 - Arbitration.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Arbitration. 204.41 Section 204.41 Foreign... § 204.41 Arbitration. Any controversy or claim between A.I.D. and the Lender or any Assignee arising out of this Guaranty shall be settled by arbitration to be held in Washington, DC in accordance with...

  13. 28 CFR 527.41 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Definitions. 527.41 Section 527.41 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INMATE ADMISSION, CLASSIFICATION, AND TRANSFER TRANSFERS Transfer of Offenders To or From Foreign Countries § 527.41 Definitions. For the purpose of this rule the following definitions...

  14. 8 CFR 1240.41 - Immigration judges.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Immigration judges. 1240.41 Section 1240.41 Aliens and Nationality EXECUTIVE OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION..., 1997) § 1240.41 Immigration judges. (a) Authority. In any proceeding conducted under this part...

  15. 29 CFR 1917.41 - House falls.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false House falls. 1917.41 Section 1917.41 Labor Regulations...) MARINE TERMINALS Cargo Handling Gear and Equipment § 1917.41 House falls. (a) Span beams shall be secured... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles,...

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

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

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

  17. 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.

  18. O-GlcNAc regulates NEDD4-1 stability via caspase-mediated pathway.

    Science.gov (United States)

    Jiang, Kuan; Bai, Bingyang; Ta, Yajie; Zhang, Tingling; Xiao, Zikang; Wang, Peng George; Zhang, Lianwen

    2016-03-18

    O-GlcNAc modification of cytosolic and nuclear proteins regulates essential cellular processes such as stress responses, transcription, translation, and protein degradation. Emerging evidence indicates O-GlcNAcylation has a dynamic interplay with ubiquitination in cellular regulation. Here, we report that O-GlcNAc indirectly targets a vital E3 ubiquitin ligase enzyme of NEDD4-1. The protein level of NEDD4-1 is accordingly decreased following an increase of overall O-GlcNAc level upon PUGNAc or glucosamine stimulation. O-GlcNAc transferase (OGT) knockdown, overexpression and mutation results confirm that the stability of NEDD4-1 is negatively regulated by cellular O-GlcNAc. Moreover, the NEDD4-1 degradation induced by PUGNAc or GlcN is significantly inhibited by the caspase inhibitor. Our study reveals a regulation mechanism of NEDD4-1 stability by O-GlcNAcylation. PMID:26876577

  19. Tyroserleutide tripeptide affects calcium homeostasis of human hepatocarcinoma BEL-7402 cells

    Institute of Scientific and Technical Information of China (English)

    FU Zheng; LU Rong; LI Guoli; ZHAO Lan; GAO Weizhen; CHE Xuchun; JIAN Xu; ZHOU Chunlei; YAO Zhi

    2005-01-01

    This study aimed to observe the effects of tyroserleutide (tyrosyl-seryl-leucine, YSL) on the growth of human hepatocarcinoma BEL-7402 that was transplanted into nude mice, and explore its anti-tumor mechanism preliminarily. YSL, at doses of 80 μg·kg-1·d-1, 160μg·kg-1·d-1 and 320μg·kg-1·d-1 significantly inhibited the growth of the human hepatocarcinoma BEL-7402 tumor in nude mice, producing inhibition of 21.66%, 41.34%, and 34.78%, respectively. Ultra structure of BEL-7402 tumor in nude mice showed that YSL could induce tumor cells apoptosis and necrosis, cell organelle mitochondria and endoplasmic reticulum damage, and calcium overload. By confocal laser scanning microscopy and flow cytometry, we found that 10 μg/mL YSL rapidly induced an increase of the concentration of cytoplasmic free calcium in BEL-7402 cells in vitro, and maintained high concentrations of cytoplasmic free calcium for 1 h. Then the calcium concentration began to decrease after 2 h, and was lower than that of the control group at 4 h and 24 h (p<0.05). YSL also decreased the mitochondrial transmembrane potential of BEL-7402 cells in vitro, but had no effect on the calcium homeostasis or mitochondrial transmembrane potential of Chang liver hepatocytes. So affecting calcium homeostasis, then inducing apoptosis and necrosis may be a mechanism by which YSL inhibits the tumor growth in animal model.

  20. 41 CFR 102-41.235 - May we sell forfeited drug paraphernalia?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false May we sell forfeited drug paraphernalia? 102-41.235 Section 102-41.235 Public Contracts and Property Management Federal... Requiring Special Handling Drug Paraphernalia § 102-41.235 May we sell forfeited drug paraphernalia? No,...

  1. 41 CFR 102-41.175 - May we sell unclaimed personal property?

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false May we sell unclaimed personal property? 102-41.175 Section 102-41.175 Public Contracts and Property Management Federal Property... § 102-41.175 May we sell unclaimed personal property? Yes, you may sell unclaimed personal...

  2. Calcium: a code coupling tool

    International Nuclear Information System (INIS)

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

  3. Molecular aspects of intestinal calcium absorption.

    Science.gov (United States)

    Diaz de Barboza, Gabriela; Guizzardi, Solange; Tolosa de Talamoni, Nori

    2015-06-21

    Intestinal Ca(2+) absorption is a crucial physiological process for maintaining bone mineralization and Ca(2+) homeostasis. It occurs through the transcellular and paracellular pathways. The first route comprises 3 steps: the entrance of Ca(2+) across the brush border membranes (BBM) of enterocytes through epithelial Ca(2+) channels TRPV6, TRPV5, and Cav1.3; Ca(2+) movement from the BBM to the basolateral membranes by binding proteins with high Ca(2+) affinity (such as CB9k); and Ca(2+) extrusion into the blood. Plasma membrane Ca(2+) ATPase (PMCA1b) and sodium calcium exchanger (NCX1) are mainly involved in the exit of Ca(2+) from enterocytes. A novel molecule, the 4.1R protein, seems to be a partner of PMCA1b, since both molecules co-localize and interact. The paracellular pathway consists of Ca(2+) transport through transmembrane proteins of tight junction structures, such as claudins 2, 12, and 15. There is evidence of crosstalk between the transcellular and paracellular pathways in intestinal Ca(2+) transport. When intestinal oxidative stress is triggered, there is a decrease in the expression of several molecules of both pathways that inhibit intestinal Ca(2+) absorption. Normalization of redox status in the intestine with drugs such as quercetin, ursodeoxycholic acid, or melatonin return intestinal Ca(2+) transport to control values. Calcitriol [1,25(OH)₂D₃] is the major controlling hormone of intestinal Ca(2+) transport. It increases the gene and protein expression of most of the molecules involved in both pathways. PTH, thyroid hormones, estrogens, prolactin, growth hormone, and glucocorticoids apparently also regulate Ca(2+) transport by direct action, indirect mechanism mediated by the increase of renal 1,25(OH)₂D₃ production, or both. Different physiological conditions, such as growth, pregnancy, lactation, and aging, adjust intestinal Ca(2+) absorption according to Ca(2+) demands. Better knowledge of the molecular details of intestinal Ca(2

  4. Reversible adsorption of calcium ions by imprinted temperature sensitive gels

    Science.gov (United States)

    Alvarez-Lorenzo, Carmen; Guney, Orhan; Oya, Taro; Sakai, Yasuzo; Kobayashi, Masatoshi; Enoki, Takashi; Takeoka, Yukikazu; Ishibashi, Toru; Kuroda, Kenichi; Tanaka, Kazunori; Wang, Guoqiang; Grosberg, Alexander Yu.; Masamune, Satoru; Tanaka, Toyoichi

    2001-02-01

    With the aim of developing polymeric gels sensitive to external stimuli and able to reversibly adsorb and release divalent ions, copolymer gels of N-isopropylacrylamide (NIPA) and methacrylic (MAA) monomers were prepared. We chose calcium as a target divalent ion. Two MAAs form a complex with a calcium ion, and the NIPA component allows the polymers to swell and shrink reversibly in response to temperature. The adsorbing site develops an affinity to target ions when the adsorbing molecules come into proximity, but when they are separated, the affinity diminishes. To enhance the affinity to calcium, an imprinting technique was applied using Ca2+ and Pb2+ ions as templates in methylsulfoxide and dioxane media, respectively. The adsorption capacity of the imprinted gels was compared with that of the nonimprinted gels, and the effects of the templates, the solvents, and the amount of methacrylic monomers used in the synthesis and the medium temperature over the Ca2+ adsorption capacity of the gels from aqueous solutions were evaluated. The analysis of the adsorption revealed that (a) the adsorption can be described by the Langmuir isotherms; (b) there is an approximately linear relationship between saturation and methacrylic monomer concentration; (c) the affinity depends on the degree of gel swelling or shrinkage that can be switched on and off by temperature; (d) in the shrunken state, the affinity depends approximately linearly on the MAA concentration in the imprinted gels, whereas in the nonimprinted gels it is proportional to the square of MAA concentration; (e) the imprinted gels adsorb more than the nonimprinted gels when MAA concentration is less than that of permanent cross linkers. The success of imprinting of CaMAA2 and PbMAA2 complex is evidence for memory of such complex onto the weakly cross-linked gel.

  5. Effects of inositol trisphosphate on calcium mobilization in high-voltage and saponin-permeabilized platelets

    International Nuclear Information System (INIS)

    Interest in phosphatidylinositol metabolism has been greatly stimulated by the findings that diglyceride and inositol phosphates may serve as second messengers in modulating cellular function. Formation of 1,4,5-inositol trisphosphate (IP3), in particular, has been linked to mobilization of intracellular calcium in a number of cell types. The authors have examined the ability of IP3 to mobilize calcium in human platelets permeabilized by either saponin or high-voltage discharge. Saponin at 15 μg/ml effectively permeabilized platelets to exogenous inositol 1,4,5-trisphosphate which released bound [45Ca] within 1 min and with a Ka of 7.4 +/- 4.1 μM. A small (25%) azide-sensitive pool was also responsive to inositol trisphosphate. The calcium pools were completely discharged by A-23187 and the ATP-dependent uptake was prevented by dinitrophenol. In contrast to the result with saponin, platelets accessed by high-voltage discharge were insensitive to challenge by inositol 1,4,5-trisphosphate. The data suggest that while inositol 1,4,5-trisphosphate can rapidly mobilize platelet calcium, the ability to demonstrate this depends on the method of permeabilization

  6. TRPV4 and AQP4 Channels Synergistically Regulate Cell Volume and Calcium Homeostasis in Retinal Müller Glia

    DEFF Research Database (Denmark)

    Jo, Andrew O; Ryskamp, Daniel A; Phuong, Tam T T;

    2015-01-01

    facilitates the time course and amplitude of hypotonicity-induced swelling and regulatory volume decrease. We confirm the crucial facets of the signaling mechanism in heterologously expressing oocytes. These results identify the molecular mechanism that contributes to dynamic regulation of glial volume but...... Ca(2+) entry through TRPV4 channels reciprocally modulates volume regulation, swelling, and Aqp4 gene expression. Therefore, TRPV4-AQP4 interactions constitute a molecular system that fine-tunes astroglial volume regulation by integrating osmosensing, calcium signaling, and water transport and, when...... complex set of mechanisms involving reciprocal interactions at the level of glial gene expression, calcium homeostasis, swelling, and volume regulation. Specifically, water influx through AQP4 drives calcium influx via TRPV4 in the glial end foot, which regulates expression of Aqp4 and Kir4.1 genes and...

  7. Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

    International Nuclear Information System (INIS)

    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

  8. Lenalidomide Stabilizes the Erythropoietin Receptor by Inhibiting the E3 Ubiquitin Ligase RNF41.

    Science.gov (United States)

    Basiorka, Ashley A; McGraw, Kathy L; De Ceuninck, Leentje; Griner, Lori N; Zhang, Ling; Clark, Justine A; Caceres, Gisela; Sokol, Lubomir; Komrokji, Rami S; Reuther, Gary W; Wei, Sheng; Tavernier, Jan; List, Alan F

    2016-06-15

    In a subset of patients with non-del(5q) myelodysplastic syndrome (MDS), lenalidomide promotes erythroid lineage competence and effective erythropoiesis. To determine the mechanism by which lenalidomide promotes erythropoiesis, we investigated its action on erythropoietin receptor (EpoR) cellular dynamics. Lenalidomide upregulated expression and stability of JAK2-associated EpoR in UT7 erythroid cells and primary CD71+ erythroid progenitors. The effects of lenalidomide on receptor turnover were Type I cytokine receptor specific, as evidenced by coregulation of the IL3-Rα receptor but not c-Kit. To elucidate this mechanism, we investigated the effects of lenalidomide on the E3 ubiquitin ligase RNF41. Lenalidomide promoted EpoR/RNF41 association and inhibited RNF41 auto-ubiquitination, accompanied by a reduction in EpoR ubiquitination. To confirm that RNF41 is the principal target responsible for EpoR stabilization, HEK293T cells were transfected with EpoR and/or RNF41 gene expression vectors. Steady-state EpoR expression was reduced in EpoR/RNF41 cells, whereas EpoR upregulation by lenalidomide was abrogated, indicating that cellular RNF41 is a critical determinant of drug-induced receptor modulation. Notably, shRNA suppression of CRBN gene expression failed to alter EpoR upregulation, indicating that drug-induced receptor modulation is independent of cereblon. Immunohistochemical staining showed that RNF41 expression decreased in primary erythroid cells of lenalidomide-responding patients, suggesting that cellular RNF41 expression merits investigation as a biomarker for lenalidomide response. Our findings indicate that lenalidomide has E3 ubiquitin ligase inhibitory effects that extend to RNF41 and that inhibition of RNF41 auto-ubiquitination promotes membrane accumulation of signaling competent JAK2/EpoR complexes that augment Epo responsiveness. Cancer Res; 76(12); 3531-40. ©2016 AACR. PMID:27197154

  9. Calcium: A Nutrient Deserving a Special Issue

    Directory of Open Access Journals (Sweden)

    Susan J. Whiting

    2010-10-01

    Full Text Available Interest in calcium has continued since the 1980s when its role in promoting bone growth and retention was established in clinical trials of children and postmenopausal women. The human nutrition functions now attributed to calcium have expanded beyond bone health to include other conditions such as body weight maintenance. While most efforts have been focused on the findings that dietary intakes are low, there are emerging data on safety concerns of excess amounts. This Special Issue on calcium nutrition, spanning the lifecycle from critically ill neonates through to older adults, has been written by some of the leading researchers in this field.

  10. Sorption of UO22+ on calcium carbonate

    International Nuclear Information System (INIS)

    Sorption of uranyl ions on calcium carbonate from aqueous solutions featuring different concentration of calcium nitrate was studied experimentally. It is shown that uranium sorption decreases with calcium concentration growth in solution, irrespective of the ratio of solid phase and solution masses. Specific sorption of uranium per unit of the sorbent surface depends linearly on the ratio of UO22+ and Ca2+ ions activities in solution with proportionality factor (sorption equilibrium constant) 1.71 ± 0.16 mol/m2 at 20 deg C

  11. Calcium signaling in physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  12. STIM and calcium channel complexes in cancer.

    Science.gov (United States)

    Jardin, Isaac; Rosado, Juan A

    2016-06-01

    The ion Ca(2+) is a ubiquitous second messenger that mediates a variety of cellular functions. Dysfunction of the mechanisms involved in Ca(2+) homeostasis underlies a number of pathological processes, including cancer. Store-operated Ca(2+) entry (SOCE) is a major mechanism for Ca(2+) entry modulated by the intracellular Ca(2+) stores. The Ca(2+)-selective store-operated current (ICRAC) is mediated by the endoplasmic reticulum (ER) Ca(2+) sensor STIM1 and the store-operated Ca(2+) (SOC) channel Orai1, while other non-selective cation currents (ISOC) involves the participation of members of the canonical transient receptor potential (TRPC) channel family, including TRPC1. Distinct isoforms of the key components of SOCE have been described in mammalian cells, STIM1 and 2, Orai1-3 and TRPC1-7. In cancer cells, SOCE has been reported to play an important role in cell cycle progression and proliferation, migration, metastasis and evasion of apoptosis. Changes in the expression of the key elements of SOCE and Ca(2+) homeostasis remodeling have been account to play important roles in the phenotypic changes observed in transformed cells. Despite there are differences in the expression level of the molecular components of SOCE, as well as in the relevance of the STIM, Orai and TRPC isoforms in SOCE and tumorigenesis among cancer cell types, there is a body of evidence supporting an important role for SOCE underlying the phenotypic modifications of cancer cells that propose STIM and the SOC channels as suitable candidate targets for future prognostic or therapeutic strategies. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen. PMID:26455959

  13. Targeted Learning

    CERN Document Server

    van der Laan, Mark J

    2011-01-01

    The statistics profession is at a unique point in history. The need for valid statistical tools is greater than ever; data sets are massive, often measuring hundreds of thousands of measurements for a single subject. The field is ready to move towards clear objective benchmarks under which tools can be evaluated. Targeted learning allows (1) the full generalization and utilization of cross-validation as an estimator selection tool so that the subjective choices made by humans are now made by the machine, and (2) targeting the fitting of the probability distribution of the data toward the targe

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

    OpenAIRE

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

    2015-01-01

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

  15. 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.

  16. A Low Affinity GCaMP3 Variant (GCaMPer for Imaging the Endoplasmic Reticulum Calcium Store.

    Directory of Open Access Journals (Sweden)

    Mark J Henderson

    Full Text Available Endoplasmic reticulum calcium homeostasis is critical for cellular functions and is disrupted in diverse pathologies including neurodegeneration and cardiovascular disease. Owing to the high concentration of calcium within the ER, studying this subcellular compartment requires tools that are optimized for these conditions. To develop a single-fluorophore genetically encoded calcium indicator for this organelle, we targeted a low affinity variant of GCaMP3 to the ER lumen (GCaMPer (10.19. A set of viral vectors was constructed to express GCaMPer in human neuroblastoma cells, rat primary cortical neurons, and human induced pluripotent stem cell-derived cardiomyocytes. We observed dynamic changes in GCaMPer (10.19 fluorescence in response to pharmacologic manipulations of the ER calcium store. Additionally, periodic calcium efflux from the ER was observed during spontaneous beating of cardiomyocytes. GCaMPer (10.19 has utility in imaging ER calcium in living cells and providing insight into luminal calcium dynamics under physiologic and pathologic states.

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2016-01-01

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

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

    Science.gov (United States)

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

  1. Effects of Adding Chymosin to Milk on Calcium Homeostasis

    DEFF Research Database (Denmark)

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

    2014-01-01

    Calcium intake and absorption is important for bone health. In a randomized double-blind cross-over trial, we investigated effects of adding chymosin to milk on the intestinal calcium absorption as measured by renal calcium excretion and indices of calcium homeostasis. The primary outcome of the...

  2. Assessment of calcium content of lumbarspine by computed tomography

    International Nuclear Information System (INIS)

    Assessment of calcium content of lumbar spine by computed tomography was performed on 76 patients without bone disease and 15 patients with chronic renal failure. Calcium content of medulla and cortex was calculated by CT number. Relationship between calcium content of medulla, cortex and age was discussed. The necessity of midline scan of lumbar spine to obtain the accurate calcium was also stressed. (author)

  3. 21 CFR 172.120 - Calcium disodium EDTA.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium disodium EDTA. 172.120 Section 172.120 Food... Food Preservatives § 172.120 Calcium disodium EDTA. The food additive calcium disodium EDTA (calcium... 100 Promote color retention. 1 By weight of egg yolk portion. (2) With disodium EDTA...

  4. Astrocyte calcium signaling: the third wave.

    Science.gov (United States)

    Bazargani, Narges; Attwell, David

    2016-01-27

    The discovery that transient elevations of calcium concentration occur in astrocytes, and release 'gliotransmitters' which act on neurons and vascular smooth muscle, led to the idea that astrocytes are powerful regulators of neuronal spiking, synaptic plasticity and brain blood flow. These findings were challenged by a second wave of reports that astrocyte calcium transients did not mediate functions attributed to gliotransmitters and were too slow to generate blood flow increases. Remarkably, the tide has now turned again: the most important calcium transients occur in fine astrocyte processes not resolved in earlier studies, and new mechanisms have been discovered by which astrocyte [Ca(2+)]i is raised and exerts its effects. Here we review how this third wave of discoveries has changed our understanding of astrocyte calcium signaling and its consequences for neuronal function. PMID:26814587

  5. Obtainment of calcium carbonate from mussels shell

    International Nuclear Information System (INIS)

    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)

  6. Modeling and analysis of calcium bromide hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, Steven A.; Lyczkowski, Robert W.; Panchal, Chandrakant B.; Doctor, Richard D. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2009-05-15

    The main focus of this paper is the modeling, simulation, and analysis of the calcium bromide hydrolysis reactor stage in the calcium-bromine thermochemical water-splitting cycle for nuclear hydrogen production. One reactor concept is to use a spray of calcium bromide into steam, in which the heat of fusion supplies the heat of reaction. Droplet models were built up in a series of steps incorporating various physical phenomena, including droplet flow, heat transfer, phase change, and reaction, separately. Given the large heat reservoir contained in a pool of molten calcium bromide that allows bubbles to rise easily, using a bubble column reactor for the hydrolysis appears to be a feasible and promising alternative to the spray reactor concept. The two limiting cases of bubble geometry, spherical and spherical-cap, are considered in the modeling. Results for both droplet and bubble modeling with COMSOL MULTIPHYSICS trademark are presented, with recommendations for the path forward. (author)

  7. Discrete stochastic modeling of calcium channel dynamics

    CERN Document Server

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

    1999-01-01

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

  8. Discrete Stochastic Modeling of Calcium Channel Dynamics

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    Highlights: ► Calcium hydroxyapatite was synthesized from CaCO3 and four orthophosphates. ► Only H3PO4 led to the complete precipitation of orthophosphate species. ► H3PO4 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.

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

    OpenAIRE

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Abarbanel Henry DI

    2007-02-01

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

  12. Calcium entry into guinea-pig jejunum cells after calcium stores depletion.

    Science.gov (United States)

    Pacaud, P; Bolton, T B

    1991-01-01

    1) Membrane currents were recorded under voltage-clamp from cells using patch-clamp pipettes. Cells were dialysed with potassium-free caesium solution to block any Ca-activated K-current. The pipette solution contained Indo-1 and the ratio of the emissions from this dye at 480 and 405 nm was used to estimate the free calcium concentration in the cell. 2) Carbachol applied to the cell evoked at -50 mV an initial increase in the intracellular calcium concentration (Cai) followed by a smaller sustained rise (plateau); the changes in inward cationic current (ICarb) closely followed changes in Cai. Calcium entry blockers did not affect these responses. 3) The initial peak in Cai produced by carbachol was due to calcium store release: it was present in calcium-free solution, and unchanged at +50 mV, but it was abolished by prior application of caffeine (10 mM) to the cell or by inclusion of heparin (which blocks D-myoinositol 1,4,5-trisphosphate receptors) in the pipette. 4) The sustained rise (plateau) in Cai produced by carbachol was due to the entry of calcium into the cell down its electrochemical gradient as it was affected by changing the cell membrane potential or the calcium concentration in the bathing solution. As the sustained rise in Cai produced by caffeine had similar properties it was suggested that depletion of calcium stores can evoke an increased calcium entry into the cell through some pathway. PMID:1665265

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

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

    OpenAIRE

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

    1981-01-01

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

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

    International Nuclear Information System (INIS)

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

  16. Hierarchical clustering of ryanodine receptors enables emergence of a calcium clock in sinoatrial node cells.

    Science.gov (United States)

    Stern, Michael D; Maltseva, Larissa A; Juhaszova, Magdalena; Sollott, Steven J; Lakatta, Edward G; Maltsev, Victor A

    2014-05-01

    The sinoatrial node, whose cells (sinoatrial node cells [SANCs]) generate rhythmic action potentials, is the primary pacemaker of the heart. During diastole, calcium released from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) interacts with membrane currents to control the rate of the heartbeat. This "calcium clock" takes the form of stochastic, partially periodic, localized calcium release (LCR) events that propagate, wave-like, for limited distances. The detailed mechanisms controlling the calcium clock are not understood. We constructed a computational model of SANCs, including three-dimensional diffusion and buffering of calcium in the cytosol and SR; explicit, stochastic gating of individual RyRs and L-type calcium channels; and a full complement of voltage- and calcium-dependent membrane currents. We did not include an anatomical submembrane space or inactivation of RyRs, the two heuristic components that have been used in prior models but are not observed experimentally. When RyRs were distributed in discrete clusters separated by >1 µm, only isolated sparks were produced in this model and LCR events did not form. However, immunofluorescent staining of SANCs for RyR revealed the presence of bridging RyR groups between large clusters, forming an irregular network. Incorporation of this architecture into the model led to the generation of propagating LCR events. Partial periodicity emerged from the interaction of LCR events, as observed experimentally. This calcium clock becomes entrained with membrane currents to accelerate the beating rate, which therefore was controlled by the activity of the SERCA pump, RyR sensitivity, and L-type current amplitude, all of which are targets of β-adrenergic-mediated phosphorylation. Unexpectedly, simulations revealed the existence of a pathological mode at high RyR sensitivity to calcium, in which the calcium clock loses synchronization with the membrane, resulting in a paradoxical decrease in beating

  17. The calcium-dependent protein kinase 3 of toxoplasma influences basal calcium levels and functions beyond egress as revealed by quantitative phosphoproteome analysis.

    Directory of Open Access Journals (Sweden)

    Moritz Treeck

    2014-06-01

    Full Text Available Calcium-dependent protein kinases (CDPKs are conserved in plants and apicomplexan parasites. In Toxoplasma gondii, TgCDPK3 regulates parasite egress from the host cell in the presence of a calcium-ionophore. The targets and the pathways that the kinase controls, however, are not known. To identify pathways regulated by TgCDPK3, we measured relative phosphorylation site usage in wild type and TgCDPK3 mutant and knock-out parasites by quantitative mass-spectrometry using stable isotope-labeling with amino acids in cell culture (SILAC. This revealed known and novel phosphorylation events on proteins predicted to play a role in host-cell egress, but also a novel function of TgCDPK3 as an upstream regulator of other calcium-dependent signaling pathways, as we also identified proteins that are differentially phosphorylated prior to egress, including proteins important for ion-homeostasis and metabolism. This observation is supported by the observation that basal calcium levels are increased in parasites where TgCDPK3 has been inactivated. Most of the differential phosphorylation observed in CDPK3 mutants is rescued by complementation of the mutants with a wild type copy of TgCDPK3. Lastly, the TgCDPK3 mutants showed hyperphosphorylation of two targets of a related calcium-dependent kinase (TgCDPK1, as well as TgCDPK1 itself, indicating that this latter kinase appears to play a role downstream of TgCDPK3 function. Overexpression of TgCDPK1 partially rescues the egress phenotype of the TgCDPK3 mutants, reinforcing this conclusion. These results show that TgCDPK3 plays a pivotal role in regulating tachyzoite functions including, but not limited to, egress.

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

    International Nuclear Information System (INIS)

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

  19. 21 CFR 201.70 - Calcium labeling.

    Science.gov (United States)

    2010-04-01

    ... product is more than 3.2 grams: “Ask a doctor before use if you have 1 kidney stones a calcium-restricted diet”. The warnings in §§ 201.64(c), 201.70(c), 201.71(c), and 201.72(c) may be combined, if applicable, provided the ingredients are listed in alphabetical order, e.g., a calcium or sodium restricted diet. 1...

  20. Modulation of intestinal absorption of calcium

    International Nuclear Information System (INIS)

    Absorption of ingested calcium (2ml of a 10mM CaCl2 solution + 45Ca) 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 CaCl2 solution. Conversely, the simultaneous ingestion of increasing doses (10 to 100mM) of phosphate (NaH2PO4) with a 10mM CaCl2 solution results in decreased 45Ca 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 CaCl2). The simultaneous ingestion of CaCl2 (10mM) with lactose and sodium phosphate (50 and 10mM respectively) shows that the activation effect of lactose upon 45Ca absorption may be partly dissimulated by the presence of phosphate. These various observations indicate that, within a large concentration range (2 to 50mM CaCl2) 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

  1. Oral calcium supplementation in peripartum dairy cows.

    Science.gov (United States)

    Oetzel, Garrett R

    2013-07-01

    Hypocalcemia in dairy cattle around parturition can be manifest as clinical milk fever or subclinical hypocalcemia. Subclinical hypocalcemia has the greatest economic effect because it affects a much higher proportion of cows. Oral calcium supplements are used to mitigate the effects of both forms of hypocalcemia. Oral calcium supplements are appropriate for cows displaying early clinical signs of hypocalcemia and prophylactically to lessen the negative impacts of hypocalcemia. PMID:23809900

  2. DETERMINATION OF CALCIUM CONTENT IN DIETARY SUPPLEMENTS

    OpenAIRE

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

    2015-01-01

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

  3. Rickets induced by calcium or phosphate depletion.

    OpenAIRE

    Abugassa, S.; Svensson, O.

    1990-01-01

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

  4. Gel time of calcium acrylate grouting material.

    Science.gov (United States)

    Han, Tong-Chun

    2004-08-01

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

  5. Understanding calcium dynamics experiments and theory

    CERN Document Server

    Malchow, Dieter

    2003-01-01

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

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

    CERN Document Server

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

    2003-01-01

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

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

    Science.gov (United States)

    Lee, Young-Seon; Keener, James P

    2008-08-21

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

  8. Analytical models of calcium binding in a calcium channel

    International Nuclear Information System (INIS)

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

  9. Contribution of calcium oxalate to soil-exchangeable calcium

    Science.gov (United States)

    Dauer, Jenny M.; Perakis, Steven S.

    2013-01-01

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

  10. Measurements of natural 41Ca concentrations

    International Nuclear Information System (INIS)

    Atomic mass spectroscopic examinations on 41Ca were carried out in the UNILAC accelerator. A sensitivity of about 10-15 was achieved. This would allow the measurement of present natural 41Ca concentrations as soon as the problem of the transmission determination is solved. In this respect suggestions were worked out and their feasibility discussed. The detection of 41Ca-ions is especially free of background when high UNILAC-energies are applied. An estimation showed a background level corresponding with a 41Ca concentration of less then 10-17 referred to 40Ca. Besides an independent concept for the electromagnetic concentration of 41Ca with variable concentration factors was developed. After being concentrated up to 50 respectively 25 times the initial concentration in the GSI mass separator, the 41Ca concentration of three recent deer bones found in the Odenwald was measured by atomic mass spectroscopy in the 14UD-Pelletron Tandem in Rehovot (Israel). The measured 41Ca concentrations ranged between 10-14 to 10-13 with consideration of the concentration factor. A theoretical study of the 41Ca production in the earth's surface based on cosmic radiation illustrates the influence of trace elements on the neutron flux and thus on the 41Ca production. This influence might be a possible explanation for the observed amplitude of variation of the 41Ca concentration in recent bones which are of decisive importance for the feasibility of 41Ca-related dating. In this work a method is suggested that does not depend on the amplitude of variation mentioned above and which would allow the determination of the erosion rate of rocks by its 41Ca concentrations. (orig./HP)

  11. 48 CFR 2131.205-41 - Taxes.

    Science.gov (United States)

    2010-10-01

    ....S.C. 8714(c) or other Federal law prohibits the imposition of taxes, fees, or other monetary... preempted tax is an unallowable expense under FAR 31.205-41(b)(3). (c) Paragraph (b)(1) of FAR 31.205-41 is...) Notwithstanding any other provision in FAR 31.205-41, an amount equal to the “DAC Tax” is an allowable tax...

  12. A coated-wire ion-selective electrode for ionic calcium measurements

    Science.gov (United States)

    Hines, John W.; Arnaud, Sara; Madou, Marc; Joseph, Jose; Jina, Arvind

    1991-01-01

    A coated-wire ion-selective electrode for measuring ionic calcium was developed, in collaboration with Teknektron Sensor Development Corporation (TSDC). This coated wire electrode sensor makes use of advanced, ion-responsive polyvinyl chloride (PVC) membrane technology, whereby the electroactive agent is incorporated into a polymeric film. The technology greatly simplifies conventional ion-selective electrode measurement technology, and is envisioned to be used for real-time measurement of physiological and environment ionic constituents, initially calcium. A primary target biomedical application is the real-time measurement of urinary and blood calcium changes during extended exposure to microgravity, during prolonged hospital or fracture immobilization, and for osteoporosis research. Potential advanced life support applications include monitoring of calcium and other ions, heavy metals, and related parameters in closed-loop water processing and management systems. This technology provides a much simplified ionic calcium measurement capability, suitable for both automated in-vitro, in-vivo, and in-situ measurement applications, which should be of great interest to the medical, scientific, chemical, and space life sciences communities.

  13. Membrane associated complexes in calcium dynamics modelling

    International Nuclear Information System (INIS)

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

  14. Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2014-05-01

    Full Text Available Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA. Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.

  15. The effect of dimethylsulfoxide on the calcium paradox.

    OpenAIRE

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

    1981-01-01

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

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

    OpenAIRE

    Shangraw, R F

    1989-01-01

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

  17. The spatial pattern of atrial cardiomyocyte calcium signalling modulates contraction

    OpenAIRE

    Mackenzie, L; Roderick, H Llewelyn; Berridge, MJ; Conway, SJ; Bootman, MD

    2004-01-01

    We examined the regulation of calcium signalling in atrial cardiomyocytes during excitation-contraction coupling, and how changes in the distribution of calcium impacts on contractility. Under control conditions, calcium transients originated in subsarcolemmal locations and showed local regeneration through activation of calcium-induced calcium release from ryanodine receptors. Despite functional ryanodine receptors being expressed at regular (~2 μm) intervals throughout atrial myocytes, the ...

  18. Increased absolute calcium binding to albumin in hypoalbuminaemia.

    OpenAIRE

    Besarab, A; Caro, J F

    1981-01-01

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

  19. Effect of Calcium Oxide Microstructure on the Diffusion of Isotopes

    CERN Document Server

    Fernandes Ramos, João Pedro; Stora, T

    2012-01-01

    Calcium oxide (CaO) powder targets have been successfully used at CERN-ISOLDE to produce neutron deficient exotic argon and carbon isotopes under proton irradiation at high temperatures (>1000°C). These targets outperform the other related targets for the production of the same beams. However, they presented either slow release rates (yields) from the beginning or a rapid decrease over time. This problem was believed to come from the target microstructure degradation, justifying the material investigation. In order to do so, the synthesis, reactivity in ambient air and sintering kinetics of CaO were studied, through surface area determination by N2 adsorption, X-ray diffraction for crystalline phase identification and crystallite size determination, and scanning and transmission electron microscopy to investigate the microstructure. The synthesis studies revealed that a nanometric material is obtained from the decarbonation of CaCO3 in vacuum at temperatures higher than 550°C, which is very reactive in air....

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  1. Increased calcium absorption from synthetic stable amorphous calcium carbonate: Double-blind randomized crossover clinical trial in post-menopausal women

    Science.gov (United States)

    Calcium supplementation is a widely recognized strategy for achieving adequate calcium intake. We designed this blinded, randomized, crossover interventional trial to compare the bioavailability of a new stable synthetic amorphous calcium carbonate (ACC) with that of crystalline calcium carbonate (C...

  2. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic

  3. The formation of calcium phosphate coatings by pulse laser deposition on the surface of polymeric ferroelectric

    Energy Technology Data Exchange (ETDEWEB)

    Bolbasov, E.N. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Lapin, I.N.; Svetlichnyi, V.A. [Tomsk State University, 36 Lenin Avenue, Tomsk 634050 (Russian Federation); Lenivtseva, Y.D. [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation); Malashicheva, A. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); ITMO University, Institute of translational Medicine, St. Petersburg (Russian Federation); Malashichev, Y. [St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034 (Russian Federation); Golovkin, A.S. [Federal Almazov Medical Research Centre, 2 Akkuratova St., St. Petersburg 197341 (Russian Federation); Anissimov, Y.G. [Griffith University, School of Natural Sciences, Engineering Dr., Southport, QLD 4222 (Australia); Tverdokhlebov, S.I., E-mail: tverd@tpu.ru [Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk 634050 (Russian Federation)

    2015-09-15

    Graphical abstract: - Highlights: • Calcium phosphate coatings were obtained on ferroelectric polymer materials surface by using PLD method. • Obtained coatings have well-developed surface. • Depending on sputtering target composition it is possible to obtain crystalline or amorphous coating. • Formation of coating does not change the crystal structure of the ferroelectric polymer material. - Abstract: This work analyses the properties of calcium phosphate coatings obtained by pulsed laser deposition on the surface of the ferroelectric polymer material. Atomic force and scanning electron microscopy studies demonstrate that, regardless of the type of sputtering target, the calcium phosphate coatings have a multiscale rough surface that is potentially capable of promoting the attachment and proliferation of osteoblasts. This developed surface of the coatings is due to its formation mainly from a liquid phase. The chemical and crystalline composition of the coatings depends on the type of sputtering target used. It was shown that, regardless of the type of sputtering target, the crystalline structure of the ferroelectric polymer material does not change. Cell viability and adhesion studies of mesenchymal stromal cells on the coatings were conducted using flow cytometry and fluorescent microscopy. These studies indicated that the produced coatings are non-toxic.

  4. 3H-tetracycline as a proxy for 41Ca for measuring dietary perturbations of bone resorption

    Science.gov (United States)

    Weaver, Connie; Cheong, Jennifer; Jackson, George; Elmore, David; McCabe, George; Martin, Berdine

    2007-06-01

    Our group is interested in evaluating early effects of dietary interventions on bone loss. Postmenopausal women lose bone following reduction in estrogen which leads to increased risk of fracture. Traditional means of monitoring bone loss and effectiveness of treatments include changes in bone density, which takes 6 months to years to observe effects, and changes in biochemical markers of bone turnover, which are highly variable and lack specificity. Prelabeling bone with 41Ca and measuring urinary 41Ca excretion with accelerator mass spectrometry provides a sensitive, specific, and rapid approach to evaluating effectiveness of treatment. To better understand 41Ca technology as a tool for measuring effective treatments on reducing bone resorption, we perturbed bone resorption by manipulating dietary calcium in rats. We used 3H-tetracycline (3H-TC) as a proxy for 41Ca and found that a single dose is feasible to study bone resorption. Suppression of bone resorption, as measured by urinary 3H-TC, by dietary calcium was observed in rats stabilized after ovariectomy, but not in recently ovariectomized rats.

  5. 3H-tetracycline as a proxy for 41Ca for measuring dietary perturbations of bone resorption

    International Nuclear Information System (INIS)

    Our group is interested in evaluating early effects of dietary interventions on bone loss. Postmenopausal women lose bone following reduction in estrogen which leads to increased risk of fracture. Traditional means of monitoring bone loss and effectiveness of treatments include changes in bone density, which takes 6 months to years to observe effects, and changes in biochemical markers of bone turnover, which are highly variable and lack specificity. Prelabeling bone with 41Ca and measuring urinary 41Ca excretion with accelerator mass spectrometry provides a sensitive, specific, and rapid approach to evaluating effectiveness of treatment. To better understand 41Ca technology as a tool for measuring effective treatments on reducing bone resorption, we perturbed bone resorption by manipulating dietary calcium in rats. We used 3H-tetracycline (3H-TC) as a proxy for 41Ca and found that a single dose is feasible to study bone resorption. Suppression of bone resorption, as measured by urinary 3H-TC, by dietary calcium was observed in rats stabilized after ovariectomy, but not in recently ovariectomized rats

  6. Anodic Behavior of Alloy 22 in Calcium Chloride and in Calcium Chloride Plus Calcium Nitrate Brines

    Energy Technology Data Exchange (ETDEWEB)

    Evans, K J; Day, S D; Ilevbare, G O; Whalen, M T; King, K J; Hust, G A; Wong, L L; Estill, J C; Rebak, R B

    2003-05-13

    Alloy 22 (UNS N60622) is a nickel-based alloy, which is extensively used in aggressive industrial applications, especially due to its resistance to localized corrosion and stress corrosion cracking in high chloride environments. The purpose of this work was to characterize the anodic behavior of Alloy 22 in concentrated calcium chloride (CaCl{sub 2}) brines and to evaluate the inhibitive effect of nitrate, especially to localized corrosion. Standard electrochemical tests such as polarization resistance and cyclic polarization were used. Results show that the corrosion potential of Alloy 22 was approximately -360 mV in the silver-silver chloride (SSC) scale and independent of the tested temperature. Cyclic polarization tests showed that Alloy 22 was mainly susceptible to localized attack in 5 M CaCl{sub 2} at 75 C and higher temperatures. The addition of nitrate in a molar ratio of chloride to nitrate equal to 10 increased the onset of localized corrosion to approximately 105 C. The addition of nitrate to the solution also decreased the uniform corrosion rate and the passive current of the alloy.

  7. Update on calcium pyrophosphate deposition.

    Science.gov (United States)

    Abhishek, Abhishek; Doherty, Michael

    2016-01-01

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

  8. Discovery of novel tetrahydroisoquinoline derivatives as orally active N-type calcium channel blockers with high selectivity for hERG potassium channels.

    Science.gov (United States)

    Ogiyama, Takashi; Inoue, Makoto; Honda, Shugo; Yamada, Hiroyoshi; Watanabe, Toshihiro; Gotoh, Takayasu; Kiso, Tetsuo; Koakutsu, Akiko; Kakimoto, Shuichiro; Shishikura, Jun-ichi

    2014-12-15

    N-type calcium channels represent a promising target for the treatment of neuropathic pain. The selective N-type calcium channel blocker ziconotide ameliorates severe chronic pain but has a narrow therapeutic window and requires intrathecal administration. We identified tetrahydroisoquinoline derivative 1a as a novel potent N-type calcium channel blocker. However, this compound also exhibited potent inhibitory activity against hERG channels. Structural optimizations led to identification of (1S)-(1-cyclohexyl-3,4-dihydroisoquinolin-2(1H)-yl)-2-{[(1-hydroxycyclohexyl)methyl]amino}ethanone ((S)-1h), which exhibited high selectivity for hERG channels while retaining potency for N-type calcium channel inhibition. (S)-1h went on to demonstrate in vivo efficacy as an orally available N-type calcium channel blocker in a rat spinal nerve ligation model of neuropathic pain. PMID:25456079

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

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.

    1999-01-01

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

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

    DEFF Research Database (Denmark)

    Hounsgaard, J; Kiehn, O

    1993-01-01

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

  11. Characterization of dihydropyridine-sensitive calcium channels

    International Nuclear Information System (INIS)

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

  12. GPR41 and GPR43 in Obesity and Inflammation - Protective or Causative?

    Science.gov (United States)

    Ang, Zhiwei; Ding, Jeak Ling

    2016-01-01

    GPR41 and GPR43 are a pair of mammalian G protein-coupled receptors (GPCRs) expressed in human adipocytes, colon epithelial cells, and peripheral blood mononuclear cells. These receptors are activated by short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate - which are produced during dietary fiber fermentation by resident gut bacteria. This unique ligand specificity suggests that GPR41 and GPR43 may mediate the interaction between the human host and the gut microbiome. Indeed, studies on knockout mice implicate GPR41 and GPR43 in chronic inflammatory disorders such as obesity, colitis, asthma and arthritis. However, whether GPR41 and GPR43 are protective or causative is inconsistent between studies. This discrepancy may be due to differences in the disease models used, the inbred mouse strains, or non-specific knockout effects. Here, we review the latest findings on GPR41 and GPR43, highlighting contradictory observations. With GPR41 and GPR43 being considered as drug targets, it is pertinent that their role is fully elucidated. We propose that future studies on human tissues, ex vivo, may allow us to confirm the role of GPR41 and GPR43 in humans, be it protective or causative. PMID:26870043

  13. A study of the 40Ar(p,γ)41K reaction

    International Nuclear Information System (INIS)

    This experiment has been undertaken to gain information on 40Ar(p,γ)41K resonances and the 41K nucleus. The targets were prepared by implanting high purity argon gas into tantalum backings. Proton beams were produced by the 2,6 MeV Van de Graaff accelerator at the Potchefstroom University for CHE. The spread in beam energy was 1 keV at 1 MeV. The excitation curve for the 40Ar(p,γ)41K reaction has been measured in the energy range 0,9 MeV 40Ar(p,γ)41K resonances. The gamma decay of these resonances have been studied utilizing a large Ge(Li) detector. The uncertain 4.03→2.32 and 4.75→1.70 keV transitions are confirmed. 9 figs., 30 refs., 5 tabs

  14. Study on bone resorption behavior of osteoclast under drug effect using {sup 41}Ca tracing

    Energy Technology Data Exchange (ETDEWEB)

    Dong Kejun [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Lu Liyan [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); CNNC Third Qinshan Nuclear Power Co. Ltd., Haiyan 314300 (China); He Ming; Ouyang Yinggen; Xue Yan; Li Chaoli; Wu Shaoyong [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Wang Xianggao [College of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Shen Hongtao [College of Physics and Technology, Guangxi Normal University, Guilin 541004 (China); Gao Jianjun [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Wang Wei [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); China National Nuclear Corporation, Beijing 100822 (China); Chen Dafu; Xing Yonggang [Beijing Research Institute of Traumatology and Orthopaedics, Beijing 100035 (China); Jian, Yuan [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China); Jiang Shan, E-mail: jiangs@ciae.ac.cn [China Institute of Atomic Energy, P.O. Box 275(50), Beijing 102413 (China)

    2013-01-15

    The mechanisms governing calcium fluxes during bone remodeling processes in Osteoporosis (OP) patients are poorly known. Understanding the changes of Osteoclasts (OC) during this dynamic transition is important to prevent and cure OP. The exploration of long-lived {sup 41}Ca (T{sub 1/2} = 1.04 Multiplication-Sign 10{sup 5} years) tracer combined with AMS measurements leads to the possibility of monitoring the bone resorption behavior of OC in OP patients. In this work, the behavior of OC with the administration of Strontium Ranelate (SR), a drug for OP, was studied by using {sup 41}Ca labeled hydroxyapatite (HAP) to simulate the bone. AMS on the HI-13 tandem accelerator at CIAE was used to determine trace amounts of {sup 41}Ca. The results show that the technique of {sup 41}Ca tracing with AMS can be used to quantitatively monitor the behavior of OC in bone resorption under the effects of drugs. Experimental details and preliminary results will be presented.

  15. Drugs Used in Paediatric Bone and Calcium Disorders.

    Science.gov (United States)

    Cheung, Moira S

    2015-01-01

    Calcium and bone disorders in children and adolescents are treated with a wide variety of drugs. Several of these drugs have been used for many years on the basis of accepted practice, without being subjected to rigorous trials. Bisphosphonates are the mainstay treatment for children with osteoporosis, but newer, more potent compounds such as zoledronate and risedronate have begun to replace the older-generation bisphosphonates. Hypocalcaemia is managed with calcium and vitamin D and its metabolites. In difficult cases that are secondary to hypoparathyroidism, subcutaneous injections or infusions of parathyroid hormone have been used. Multiple daily phosphate supplements and calcitriol are the standard treatment for hypophosphataemic rickets, but trials of an anti-fibroblast growth factor 23 antibody appear promising, and the results are eagerly awaited. Many new medications are undergoing clinical trials and are starting to emerge as viable treatment options for children. Some of these drugs target specific diseases, such as recombinant alkaline phosphatase for hypophosphatasia and a C-type natriuretic peptide analogue for achondroplasia. Other drugs, such as denosumab and odanacatib, have been used successfully in the adult population, and the appropriate use of these drugs in children is now being evaluated. PMID:26138848

  16. Calcium-ATPases: Gene disorders and dysregulation in cancer.

    Science.gov (United States)

    Dang, Donna; Rao, Rajini

    2016-06-01

    Ca(2+)-ATPases belonging to the superfamily of P-type pumps play an important role in maintaining low, nanomolar cytoplasmic Ca(2+) levels at rest and priming organellar stores, including the endoplasmic reticulum, Golgi, and secretory vesicles with high levels of Ca(2+) for a wide range of signaling functions. In this review, we introduce the distinct subtypes of Ca(2+)-ATPases and their isoforms and splice variants and provide an overview of their specific cellular roles as they relate to genetic disorders and cancer, with a particular emphasis on recent findings on the secretory pathway Ca(2+)-ATPases (SPCA). Mutations in human ATP2A2, ATP2C1 genes, encoding housekeeping isoforms of the endoplasmic reticulum (SERCA2) and secretory pathway (SPCA1) pumps, respectively, confer autosomal dominant disorders of the skin, whereas mutations in other isoforms underlie various muscular, neurological, or developmental disorders. Emerging evidence points to an important function of dysregulated Ca(2+)-ATPase expression in cancers of the colon, lung, and breast where they may serve as markers of differentiation or novel targets for therapeutic intervention. We review the mechanisms underlying the link between calcium homeostasis and cancer and discuss the potential clinical relevance of these observations. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen. PMID:26608610

  17. 38 CFR 41.405 - Management decision.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Management decision. 41... Entities § 41.405 Management decision. (a) General. The management decision shall clearly state whether or... mitigating disallowed costs. The management decision should describe any appeal process available to...

  18. 43 CFR 41.505 - Employment criteria.

    Science.gov (United States)

    2010-10-01

    ... EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or Activities Prohibited § 41.505 Employment criteria. A... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Employment criteria. 41.505 Section...

  19. 43 CFR 41.430 - Financial assistance.

    Science.gov (United States)

    2010-10-01

    ... assist in the administration of scholarships, fellowships, or other forms of financial assistance... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Financial assistance. 41.430 Section 41... SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on...

  20. 7 CFR 3016.41 - Financial reporting.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Financial reporting. 3016.41 Section 3016.41 Agriculture Regulations of the Department of Agriculture (Continued) OFFICE OF THE CHIEF FINANCIAL OFFICER... Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of this...

  1. 13 CFR 143.41 - Financial reporting.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Financial reporting. 143.41... Reports, Records, Retention, and Enforcement § 143.41 Financial reporting. (a) General. (1) Except as... authorized by OMB, for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  2. 24 CFR 85.41 - Financial reporting.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Financial reporting. 85.41 Section... § 85.41 Financial reporting. (a) General. (1) Except as provided in paragraphs (a) (2) and (5) of this... financial reports to Federal agencies, or (ii) Requesting advances or reimbursements when letters of...

  3. 15 CFR 24.41 - Financial reporting.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Financial reporting. 24.41 Section 24..., Records, Retention, and Enforcement § 24.41 Financial reporting. (a) General. (1) Except as provided in... by OMB, for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  4. 14 CFR 1273.41 - Financial reporting.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Financial reporting. 1273.41 Section 1273... Reports, Records, Retention, and Enforcement § 1273.41 Financial reporting. (a) General. (1) Except as... authorized by OMB, for: (i) Submitting financial reports to Federal agencies, or (ii) Requesting advances...

  5. 36 CFR 1207.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Financial reporting. 1207.41... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 1207.41 Financial reporting... forms as may from time to time be authorized by OMB, for: (i) Submitting financial reports to...

  6. 40 CFR 31.41 - Financial reporting.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Financial reporting. 31.41 Section 31... Post-Award Requirements Reports, Records, Retention, and Enforcement § 31.41 Financial reporting. (a... may from time to time be authorized by OMB, for: (i) Submitting financial reports to Federal...

  7. 9 CFR 147.41 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Definitions. 147.41 Section 147.41 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE... producing eggs for human consumption. Exhibition Poultry. Domesticated fowl which are bred for the...

  8. 38 CFR 41.230 - Audit costs.

    Science.gov (United States)

    2010-07-01

    ..., the Federal Acquisition Regulation (FAR) (48 CFR parts 30 and 31), or other applicable cost principles... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Audit costs. 41.230 Section 41.230 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED)...

  9. 40 CFR 436.41 - Specialized definitions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Specialized definitions. 436.41 Section 436.41 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE CATEGORY Industrial Sand Subcategory §...

  10. 28 CFR 550.41 - Urine surveillance.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Urine surveillance. 550.41 Section 550.41 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT DRUG PROGRAMS... aftercare as a condition of release; (2) Who have a known history of drug abuse; or (3) Who are suspected...

  11. 28 CFR 541.41 - Institutional referral.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Institutional referral. 541.41 Section 541.41 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT... alone or together with an inmate's prior history, may warrant consideration for a control unit...

  12. 40 CFR 142.41 - Variance request.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Variance request. 142.41 Section 142...) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Variances Issued by the Administrator Under Section 1415(a) of the Act § 142.41 Variance request. A supplier of water may request the granting of...

  13. 16 CFR 1203.41 - Recordkeeping requirements.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Recordkeeping requirements. 1203.41 Section 1203.41 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS... helmet positioning index (HPI) used to define the proper position of the helmet on the headform; (6)...

  14. 43 CFR 423.41 - Aircraft.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  15. 36 CFR 292.41 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... certain resource management practices to a particular area of land, as determined by an ecological and... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Definitions. 292.41 Section 292.41 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE...

  16. 32 CFR 728.41 - General provisions.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false General provisions. 728.41 Section 728.41 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL MEDICAL AND DENTAL CARE...) will, if appropriate, obtain State Department clearance and guidance and advise the Secretary of...

  17. 28 CFR 41.6 - Interagency cooperation.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Interagency cooperation. 41.6 Section 41.6 Judicial Administration DEPARTMENT OF JUSTICE IMPLEMENTATION OF EXECUTIVE ORDER 12250... Interagency cooperation. (a) Where each of a substantial number of recipients is receiving assistance...

  18. 37 CFR 41.126 - Arbitration.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Arbitration. 41.126 Section... COMMERCE PRACTICE BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES Contested Cases § 41.126 Arbitration. (a) Parties to a contested case may resort to binding arbitration to determine any issue in...

  19. 38 CFR 41.505 - Audit reporting.

    Science.gov (United States)

    2010-07-01

    ... differently from the manner presented in this section. The auditor's report(s) shall state that the audit was... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Audit reporting. 41.505... OF STATES, LOCAL GOVERNMENTS, AND NON-PROFIT ORGANIZATIONS Auditors § 41.505 Audit reporting....

  20. 44 CFR 295.41 - Administrative appeal.

    Science.gov (United States)

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Administrative appeal. 295.41 Section 295.41 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... supplement the statement of reasons and provide any additional documentary evidence supporting the...

  1. 22 CFR 40.41 - Public charge.

    Science.gov (United States)

    2010-04-01

    ... Consular Services (22 CFR 22.1). (c) Joint Sponsors. Submission of one or more additional affidavits of... subscribed to before a notary public by the employer or an authorized employee or agent of the employer. The... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Public charge. 40.41 Section 40.41...

  2. 48 CFR 1631.205-41 - Taxes.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Taxes. 1631.205-41 Section... PROCEDURES Contracts With Commercial Organizations 1631.205-41 Taxes. 5 U.S.C. 8909(f)(1) prohibits the imposition of taxes, fees, or other monetary payment, directly or indirectly, on FEHB premiums by any...

  3. 40 CFR 69.41 - New exemptions.

    Science.gov (United States)

    2010-07-01

    ... at 40 CFR 58.20, but will, for these purposes, be averaged by the hour, starting on the hour. (3) The... 40 Protection of Environment 15 2010-07-01 2010-07-01 false New exemptions. 69.41 Section 69.41... 1-hour averages, starting on the hour. If the average wind direction for a given hour is from...

  4. 27 CFR 41.60 - Assessment.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Assessment. 41.60 Section... PROCESSED TOBACCO Taxes Assessment of Taxes § 41.60 Assessment. Whenever any person required by law to pay... amount is nominal or the result of an evident mathematical error, no such assessment shall be made...

  5. 9 CFR 145.41 - Definitions.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Definitions. 145.41 Section 145.41 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE LIVESTOCK IMPROVEMENT NATIONAL POULTRY IMPROVEMENT PLAN FOR BREEDING POULTRY Special Provisions for...

  6. 43 CFR 41.540 - Advertising.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Advertising. 41.540 Section 41.540 Public Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

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

    Indian Academy of Sciences (India)

    B S Randhawa; Kamaljeet Sweety

    2000-08-01

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

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

    International Nuclear Information System (INIS)

    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)

  9. Skin injuries afflicting three oil workers following contact with calcium bromide and/or calcium chloride.

    Science.gov (United States)

    Saeed, W R; Distante, S; Holmes, J D; Kolhe, P S

    1997-01-01

    Calcium bromide brine is a highly concentrated aqueous solution of calcium bromide and calcium chloride. It is used extensively in the oil industry. This solution and its components are recognized as causes of skin injury and information is available from the manufacturers on their safe use and handling. Two patients who were injured following unprotected skin exposure to this solution and one patient who was injured following exposure to calcium chloride powder are reported. All sustained skin injuries characterised by an absence of pain and a delayed clinical appearance of the full extent of the injury. Furthermore healing was complicated by graft loss or was slow. Although organic bromine compounds are recognized as a cause of skin injuries, no previous reports of such injuries to humans secondary to calcium chloride or bromide exposure were found in the medical literature. Our experience with these patients is described. PMID:9568340

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

    International Nuclear Information System (INIS)

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

  11. Accelerator target

    Energy Technology Data Exchange (ETDEWEB)

    Schlyer, David J. (Bellport, NY); Ferrieri, Richard A. (Patchogue, NY); Koehler, Conrad (Miller Place, NY)

    1999-01-01

    A target includes a body having a depression in a front side for holding a sample for irradiation by a particle beam to produce a radioisotope. Cooling fins are disposed on a backside of the body opposite the depression. A foil is joined to the body front side to cover the depression and sample therein. A perforate grid is joined to the body atop the foil for supporting the foil and for transmitting the particle beam therethrough. A coolant is circulated over the fins to cool the body during the particle beam irradiation of the sample in the depression.

  12. Bone calcium turnover during pregnancy and lactation in women with low calcium diets is associated with calcium intake and circulating insulin-like growth factor 1 concentrations

    Science.gov (United States)

    BACKGROUND: Few data exist on longitudinal changes in bone calcium turnover rates across pregnancy and lactation. OBJECTIVE: Our aim was to characterize calcium kinetic variables and predictors of these changes across pregnancy and early lactation in women with low calcium intakes. DESIGN: Stable ca...

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

    CERN Document Server

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

    2005-01-01

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

  14. Role of calcium in gravity perception of plant roots

    Science.gov (United States)

    Evans, Michael L.

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

  15. A Study of Phosphorus and Calcium Dynamics in an Integrated Rainbow Trout and Spinach (Nores variety) Aquaponic System with Different Crop Densities

    OpenAIRE

    Stefan Mihai Petrea; Victor Cristea; Lorena Dediu; Maria Contoman; Mirela Cretu; Alina Antache; Marian Coada; Alexandru Cristian Bandi

    2014-01-01

    The goal of this study is to quantify both calcium and phosphorus budgets for an integrated rainbow trout – spinach (Nores variety) aquaponic system, where three crops densities were used (BH1 –59 crops/m2, BH2 – 48 crops/m2 and BH3 – 39 crops/m2 and a control variant). Fish were fed with two types of feed (41% and 50% protein), using 3 different feeding regimes. Total calcium and total phosphorus retention rates for each of the three tested spinach biomass densities were individually determi...

  16. Kit for instant 99mTc labeling of the antimicrobial peptide ubiquicidin 29-41

    International Nuclear Information System (INIS)

    The ubiquicidin 29-41 fragment (UBI) is a cationic antimicrobial peptide. An instant kit formulation was developed for the preparation of 99mTc-UBI 29-41 in high radiochemical yield and its use as an infection imaging agent in humans was evaluated. The components were selected to produce a direct 99mTc labeling, presumably to the amine groups of Lys and Arg7. 99mTc-UBI 29-41 obtained from the lyophilized kit showed radiochemical purity of >97% with an average target/non-target ratio of 2.3±0.6 in positive infection sites at 2 hours. Kits were stable at 4 deg C for over 6 months. (author)

  17. Vitamin D with Calcium Reduces Mortality

    DEFF Research Database (Denmark)

    Rejnmark, Lars; Avenell, Alison; Masud, Tahir;

    2012-01-01

    ,528 randomized participants (86.8% females) with a median age of 70 (interquartile range, 62-77) yr. Vitamin D with or without calcium reduced mortality by 7% [hazard ratio, 0.93; 95% confidence interval (CI), 0.88-0.99]. However, vitamin D alone did not affect mortality, but risk of death was reduced if vitamin...... D was given with calcium (hazard ratio, 0.91; 95% CI, 0.84-0.98). The number needed to treat with vitamin D plus calcium for 3 yr to prevent one death was 151. Trial level meta-analysis (24 trials with 88,097 participants) showed similar results, i.e. mortality was reduced with vitamin D plus...... calcium (odds ratio, 0.94; 95% CI, 0.88-0.99), but not with vitamin D alone (odds ratio, 0.98; 95% CI, 0.91-1.06).Conclusion:Vitamin D with calcium reduces mortality in the elderly, whereas available data do not support an effect of vitamin D alone....

  18. Calcium and bone disorders in pregnancy

    Directory of Open Access Journals (Sweden)

    Shriraam Mahadevan

    2012-01-01

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

  19. Calcium And Zinc Deficiency In Preeclamptic Women

    Directory of Open Access Journals (Sweden)

    Sultana Ferdousi

    2011-12-01

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

  20. Calcium's Role in Mechanotransduction during Muscle Development

    Directory of Open Access Journals (Sweden)

    Tatiana Benavides Damm

    2014-01-01

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

  1. Calcium Aluminate Cement Hydration Model

    Directory of Open Access Journals (Sweden)

    Matusinović, T.

    2011-01-01

    Full Text Available Calcium aluminate cement (AC is a very versatile special cement used for specific applications. As the hydration of AC is highly temperature dependent, yielding structurally different hydration products that continuously alter material properties, a good knowledge of thermal properties at early stages of hydration is essential. The kinetics of AC hydration is a complex process and the use of single mechanisms models cannot describe the rate of hydration during the whole stage.This paper examines the influence of temperature (ϑ=5–20 °C and water-to-cement mass ratio (mH /mAC = 0.4; 0.5 and 1.0 on hydration of commercial iron-rich AC ISTRA 40 (producer: Istra Cement, Pula, Croatia, which is a part of CALUCEM group, Figs 1–3. The flow rate of heat generation of cement pastes as a result of the hydration reactions was measured with differential microcalorimeter. Chemically bonded water in the hydrated cement samples was determined by thermo-gravimetry.Far less heat is liberated when cement and water come in contact for the first time, Fig. 1, than in the case for portland cement (PC. Higher water-to-cement ratio increases the heat evolved at later ages (Fig. 3 due to higher quantity of water available for hydration. A significant effect of the water-to-cement ratio on the hydration rate and hydration degree showed the importance of water as being the limiting reactant that slows down the reaction early. A simplified stoichiometric model of early age AC hydration (eq. (8 based on reaction schemes of principal minerals, nominally CA, C12A7 and C4AF (Table 1, was employed. Hydration kinetics after the induction period (ϑ < 20 °C had been successfully described (Fig. 4 and Table 2 by a proposed model (eq. (23 which simultaneously comprised three main mechanisms: nucleation and growth, interaction at phase boundary, and mass transfer. In the proposed kinetic model the nucleation and growth is proportional to the amount of reacted minerals (eq

  2. Photoionization of organic molecules in MCM-41, AlMCM-41 and metal containing AlMCM-41 mesoporous materials

    Science.gov (United States)

    Sinlapadech, Sunsanee

    A family of mesoporous MCM-41 and AlMCM-41 materials was successfully synthesized. Transition metal ions such as Ni(II), Cu(II), Fe(III) and Cr(III) were incorporated into these mesoporous materials by ion-exchange. The samples were characterized by powder X-ray diffraction (XRD) and nitrogen adsorption. Elemental compositions of these materials were determined by electron microprobe analysis or X-ray fluorescence. Photoionization of photosensitizer molecules N-alkylphenothiazine (PCn), N,N,N',N'-tetramethylbenzidine (TMB), pyrene (Py) and meso-tetraphenylporphine (H2 TPP) was studied in MCM-41 and modified MCM-41 mesoporous materials at room temperature. Electron spin resonance (ESR) make it possible to quantify and identify the photoionization yield of PCn+., TMB+., Py+. and H2TPP+. radical cations in the materials. Incorporation of Al into MCM-41 frameworks enhances the electron-accepting ability of the framework. Increasing the alkyl chain length of PCn affects the alkylphenothiazine cation radical photoyield and stability. The H2TPP+. photoyield was found to depend on the pore size in Cn-MCM-41 but the pore size was found to have no significant effect on the photoyield in Cn -AlMCM-41 materials. The photoyield intensity depends on the amount of the metal ion incorporated into MCM-41 materials. It is clear that Cr(V) is an electron acceptor during the photoirradiation of Cr-AlMCM-41/PC 1. PCn+., TMB+., Py +. and H2TPP+. cation radicals are stable in these oxides at room temperature from several hours to several days. These materials are shown to be effective heterogeneous hosts to achieve long-lived photoinduced electron transfer of photosensitizer molecules at room temperature.

  3. Oxidative Stress and Maxi Calcium-Activated Potassium (BK Channels

    Directory of Open Access Journals (Sweden)

    Anton Hermann

    2015-08-01

    Full Text Available All cells contain ion channels in their outer (plasma and inner (organelle membranes. Ion channels, similar to other proteins, are targets of oxidative impact, which modulates ion fluxes across membranes. Subsequently, these ion currents affect electrical excitability, such as action potential discharge (in neurons, muscle, and receptor cells, alteration of the membrane resting potential, synaptic transmission, hormone secretion, muscle contraction or coordination of the cell cycle. In this chapter we summarize effects of oxidative stress and redox mechanisms on some ion channels, in particular on maxi calcium-activated potassium (BK channels which play an outstanding role in a plethora of physiological and pathophysiological functions in almost all cells and tissues. We first elaborate on some general features of ion channel structure and function and then summarize effects of oxidative alterations of ion channels and their functional consequences.

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Calcium Phosphate Nanocomposite Particles for In Vitro Imaging and Encapsulated Chemotherapeutic Drug Delivery to Cancer Cells

    OpenAIRE

    Kester, Mark; Heakal, Y.; Sharma, A.; Robertson, Gavin P.; Morgan, Thomas T.; İ Altinoğlu, Erhan; Tabaković, Amra; Parette, Mylisa R.; Rouse, Sarah; Ruiz-Velasco, Victor; Adair, James H.

    2008-01-01

    Paradigm-shifting modalities to more efficiently deliver drugs to cancerous lesions require the following attributes: nanoscale-size, targetability and stability under physiological conditions. Often, these nanoscale drug delivery vehicles are limited due to agglomeration, poor solubility or cytotoxicity. Thus, we have designed a methodology to encapsulate hydrophobic antineoplastic chemotherapeutics within a 20-30 nm diameter, pH-responsive, non-agglomerating, non-toxic calcium phosphate nan...

  6. Trace element doping in calcium phosphate ceramics to Understand osteogenesis and angiogenesis

    OpenAIRE

    Bose, Susmita; Fielding, Gary; Tarafder, Solaiman; Bandyopadhyay, Amit

    2013-01-01

    The general trends in synthetic bone grafting materials are shifting towards approaches that can illicit osteoinductive properties. Pharmacologics and biologics have been used in combination with calcium phosphate (CaP) ceramics, however, recently have become the target of scrutiny over the safety. The importance of trace elements in natural bone health is well documented. Ions, e.g. lithium, zinc, magnesium, manganese, silicon, strontium etc. have shown to increase osteogenesis and neovascul...

  7. Lavender Oil-Potent Anxiolytic Properties via Modulating Voltage Dependent Calcium Channels

    OpenAIRE

    Schuwald, Anita M.; Nölder, Michael; Wilmes, Thomas; Klugbauer, Norbert; Leuner, Kristina; Müller, Walter E.

    2013-01-01

    Recent clinical data support the clinical use of oral lavender oil in patients suffering from subsyndromal anxiety. We identified the molecular mechanism of action that will alter the perception of lavender oil as a nonspecific ingredient of aromatherapy to a potent anxiolytic inhibiting voltage dependent calcium channels (VOCCs) as highly selective drug target. In contrast to previous publications where exorbitant high concentrations were used, the effects of lavender oil in behavioral, bioc...

  8. Luminescent properties of calcium iodide crystals

    International Nuclear Information System (INIS)

    The influence of preparation conditions, temperature and X radiation on luminescent properties of calcium iodide scintillating crystals is studied, the results are provided. The results obtained when studying spectral characteristics of CaI2 and CaI2:H2 crystals in case of optical and X-ray excitation in the temperature range of 90-400 K, allowance made for data obtained when studying luminescent properties of calcium iodide crystals activated by Cl-, Br-, OH- and Ca2+ impurities, permit assumption that band 236 nm observed in excitation spectra of calcium iodide crystals can stem from noncontrolled hydrogen impurity. Luminescence of the crystals with the maximum in the range of 395 nm is assigned to radiation recombination of excitons localized on H- ions

  9. Calcium metabolism evaluated by 47Ca kinetics

    International Nuclear Information System (INIS)

    Optimization of a four-crystal stretcher geometry whole-body (WB) counter was performed. The measured geometric characteristic did not differ significantly from the theoretically calculated characteristic (p>0.05). The linearity of the WB counter was high in the range 3.7 kBq to 3.7 MBq. Longtime variability of local background was CV = 3.7 per cent. In vivo sensitivity was calculated to 18 cpm/kBq and the detection limit to about 5 kBq. The reproducibility was estimated to 0.7 per cent. The WB counter was used in 47Ca turnover and calcium balance studies of 15 normal individuals. The data were analysed according to a modification of the expanding calcium pool model using an improved Bauer-Carlsson-Lindquist formulation. Variability and method errors of main parameters for calcium metabolism were evaluated. (Auth.)

  10. Glial calcium signaling in physiology and pathophysioilogy

    Institute of Scientific and Technical Information of China (English)

    Alexei VERKHRASKY

    2006-01-01

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

  11. 43 CFR 41.305 - Preference in admission.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Preference in admission. 41.305 Section 41... Basis of Sex in Admission and Recruitment Prohibited § 41.305 Preference in admission. A recipient to which §§ 41.300 through 41.310 apply shall not give preference to applicants for admission, on the...

  12. Increasing serotonin concentrations alter calcium and energy metabolism in dairy cows.

    Science.gov (United States)

    Laporta, Jimena; Moore, Spencer A E; Weaver, Samantha R; Cronick, Callyssa M; Olsen, Megan; Prichard, Austin P; Schnell, Brian P; Crenshaw, Thomas D; Peñagaricano, Francisco; Bruckmaier, Rupert M; Hernandez, Laura L

    2015-07-01

    A 4×4 Latin square design in which varied doses (0, 0.5, 1.0, and 1.5 mg/kg) of 5-hydroxy-l-tryptophan (5-HTP, a serotonin precursor) were intravenously infused into late-lactation, non-pregnant Holstein dairy cows was used to determine the effects of serotonin on calcium and energy metabolism. Infusion periods lasted 4 days, with a 5-day washout between periods. Cows were infused at a constant rate for 1 h each day. Blood was collected pre- and 5, 10, 30, 60, 90, and 120 min post-infusion, urine was collected pre- and post-infusion, and milk was collected daily. All of the 5-HTP doses increased systemic serotonin as compared to the 0 mg/kg dose, and the 1.0 and 1.5 mg/kg doses increased circulating glucose and non-esterified fatty acids (NEFA) and decreased beta-hydroxybutyrate (βHBA) concentrations. Treatment of cows with either 1.0 or 1.5 mg/kg 5-HTP doses decreased urine calcium elimination, and the 1.5 mg/kg dose increased milk calcium concentrations. No differences were detected in the heart rates, respiration rates, or body temperatures of the cows; however, manure scores and defecation frequency were affected. Indeed, cows that received 5-HTP defecated more, and the consistency of their manure was softer. Treatment of late-lactation dairy cows with 5-HTP improved energy metabolism, decreased loss of calcium into urine, and increased calcium secretion into milk. Further research should target the effects of increasing serotonin during the transition period to determine any benefits for post-parturient calcium and glucose metabolism. PMID:26099356

  13. Effects of calcium chelators on calcium distribution and protein solubility in rennet casein dispersions.

    Science.gov (United States)

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

    2016-04-15

    This study investigated the effects of calcium chelating salts on calcium-ion activity (ACa(++)), calcium distribution, and protein solubility in model CaCl2 solutions (50 mmol L(-1)) or rennet casein dispersions (15 g/100 g). Disodium phosphate and trisodium citrate at concentrations of 10 and 30 mmol L(-1) and at ratios of 1:0, 2:1, 1:1, 1:2 and 0:1 were added to both systems. The CaCl2 system, despite its simplicity, was a good indicator of chelating salt-calcium interactions in rennet casein dispersions. Adding trisodium citrate either alone or as part of a mixed chelating salt system resulted in high levels of dispersed "chelated" calcium; conversely, disodium phosphate addition resulted in lower levels, while the ACa(++) decreased with increasing concentration of both chelating salts. Neither chelating salt produced high levels of soluble protein. Thus calcium chelating salts may play a more subtle role in modulating hydration during manufacture of casein-based matrices than simply solubilising calcium or protein. PMID:26616945

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

    Science.gov (United States)

    Komar, N.; Zeebe, R. E.

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Isela Rojas-Molina

    2015-01-01

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

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

    Science.gov (United States)

    Komar, Nemanja; Zeebe, Richard

    2016-04-01

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

  17. STUDY OF SERUM TOTAL CALCIUM, IO NIZED CALCIUM AND TOTAL PROTEIN CONCENTRATIONS IN POSTMENOPAUSAL WOMEN

    Directory of Open Access Journals (Sweden)

    SK.Deepthi

    2015-05-01

    Full Text Available Menopause and ageing is associated with accelerated loss of cortical bone. Osteoporotic fractures are common cause of morbidity and mortality in adult Indian women due to ageing. This study was conducted to evaluate the levels of serum calcium, ionized calcium and total protein levels in postmenopausal women and to assess its relation with ageing. Study includes 70 women (40 post menopausal and 30 prem enopausal women serum alkaline phosphatase, serum calcium, ionized calcium and total proteins, serum albumin were estimated in both cases and controls. There is decrease in serum calcium in postmenopausal; wo men when compared to premenopausal women. There was no significant change in ionized calcium in both cases and controls. ALP is highly significant P<0.001. In postmenopausal women suggesting there is high alkaline phosphotase activity in postmenopausal women as a result of the inhibitory effects of estrogen on bone turnover rate which is dependent on age and body mass index. Decrease in serum albumin was seen in postmenopausal wo men which is the reason for decrease in serum calcium level which is inturn related to ageing effect.

  18. NMR study of hydrated calcium silicates

    International Nuclear Information System (INIS)

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

  19. Synthesis and characterization of porous calcium phosphate

    International Nuclear Information System (INIS)

    The porous calcium phosphate was prepared by the continuous precipitation method using Ca(NO3)2.4H2O and NH4H2PO4 salts. The synthesized material was structurally and superficially characterized using the XRD, BET, IR TGA and SEM techniques. The obtained inorganic material was identified as calcium phosphate that presents a great specific area for what can be efficiently used as adsorbent material for adsorption studies in the radioactive wastes treatment present in aqueous solution. (Author)

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

    OpenAIRE

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

    2012-01-01

    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-contro...