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Sample records for uptake immunoglobulin-mediated calcium

  1. A sensor for calcium uptake

    Science.gov (United States)

    Collins, Sean; Meyer, Tobias

    2011-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified. PMID:20844529

  2. Role of polyhydroxybutyrate in mitochondrial calcium uptake

    Science.gov (United States)

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

    2013-01-01

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

  3. Uptake of radiactive calcium by groundnut (Arachis hypogaea L. ) and efficiency of utilisation of applied calcium

    Energy Technology Data Exchange (ETDEWEB)

    Loganathan, S; Krishnamoorthy, K K [Tamil Nadu Agricultural Univ., Coimbatore (India). Dept. of Soil Science and Agricultural Chemistry

    1977-04-01

    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium.

  4. Uptake of radiactive calcium by groundnut (Arachis hypogaea L.) and efficiency of utilisation of applied calcium

    International Nuclear Information System (INIS)

    Loganathan, S.; Krishnamoorthy, K.K.

    1977-01-01

    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium

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

    Science.gov (United States)

    Yang, Bei

    2012-01-01

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

  6. Effect of ethionine on hepatic mitochondrial and microsomal calcium uptake

    International Nuclear Information System (INIS)

    Agarwal, A.K.; Zinermon, W.D.; Latoni, L.

    1988-01-01

    Ethionine, an ethyl analog of methionine, produces a variety of physiological and pathological effects in animals. These range from acute effects in the liver, kidney, pancreas, and other organs to liver carcinogenesis. Female rats when injected with ethionine exhibit a rapid decrease in hepatic adenosine triphosphate levels followed by a marked inhibition of RNA and protein synthesis and accumulation of triglycerides. Since calcium transport in mitochondria and microsomes is ATP dependent, it becomes interesting to find out if ethionine administration has any effect on subcellular calcium transport. Calcium has recently gained an increased controversy regarding its role in chemical induced lethal cell damage. Certain groups believe that influx of extracellular calcium across the damaged plasma membrane might actually mediate the irreversible damage to the cell, whereas according to other, entry of calcium into the cell is secondary to the damage. The present study was carried out to investigate the calcium [ 45 Ca] transport in mitochondria and microsomes following ethionine administration. The effect of carbon tetrachloride on calcium uptake in ethionine treated rats was also studied

  7. Calcium uptake and proton transport by acidocalcisomes of Toxoplasma gondii.

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    Peter Rohloff

    Full Text Available Acidocalcisomes are acidic calcium stores found in diverse organisms, being conserved from bacteria to humans. They possess an acidic matrix that contains several cations bound to phosphates, which are mainly present in the form of short and long polyphosphate chains. Their matrix is acidified through the action of proton pumps such as a vacuolar proton ATPase and a vacuolar proton pyrophosphatase. Calcium uptake occurs through a Ca(2+/H(+ countertransporting ATPase located in the membrane of the organelle. Acidocalcisomes have been identified in a variety of microorganisms, including Apicomplexan parasites such as Plasmodium and Eimeria species, and in Toxoplasma gondii. We report the purification and characterization of an acidocalcisome fraction from T. gondii tachyzoites after subcellular fractionation and further discontinuous iodixanol gradient purification. Proton and calcium transport activities in the fraction were characterized by fluorescence microscopy and spectrophotometric methods using acridine orange and arsenazo III, respectively. This work will facilitate the understanding of the function of acidocalcisomes in Apicomplexan parasites, as we can now isolate highly purified fractions that could be used for proteomic analysis to find proteins that may clarify the biogenesis of these organelles.

  8. In vitro effects of toxaphene on mitochondrial calcium ATPase and calcium uptake in selected rat tissues

    International Nuclear Information System (INIS)

    Trottman, C.H.; Rao, K.S.P.; Morrow, W.; Uzodinma, J.E.; Desaiah, D.

    1985-01-01

    In vitro effects of toxaphene on Ca 2+ -ATPase activity and 45 Ca 2+ -uptake were studied in mitochondrial fractions of heart, kidney and liver tissues of rat. Mitochondrial fractions were prepared by the conventional centrifugation method. Ca 2+ -ATPase activity was determined by measuring the inorganic phosphate liberated during ATP hydrolysis. Toxaphene inhibited Ca 2+ -ATPase in a concentration dependent manner in all the three tissues. Substrate activation kinetics, with heart, kidney and liver tissue fractions, revealed that toxaphene inhibited Ca 2+ -ATPase activity non-competetively by decreasing the maximum velocity of the enzyme without affecting the enzyme-substrate affinity. Toxaphene also inhibited mitochondrial 45 Ca 2+ -uptake in the three selected tissues in a concentration dependent manner. These results indicate that toxaphene is an inhibitor of mitochondrial Ca 2+ -ATPase and calcium transport in heart, kidney and liver tissues of rat. 19 references, 5 figures

  9. Deuterium oxide normalizes blood pressure and vascular calcium uptake in Dahl salt-sensitive hypertensive rats

    International Nuclear Information System (INIS)

    Vasdev, S.; Prabhakaran, V.; Sampson, C.A.

    1990-01-01

    This study examined the effect of 25% deuterium oxide in drinking water on systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas of Dahl salt-sensitive rats on 0.4% (low) and 8% (high) sodium chloride (salt) diet. Twenty-four rats were divided into four groups. Groups I and II were on the low salt diet and groups III and IV on the high salt diet from 6 weeks of age. Additionally, at 10 weeks of age groups I and III were placed on 100% water and groups II and IV on 25% deuterium oxide. At 14 weeks, systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas were significantly higher (p less than 0.01) in rats on the high salt diet as compared with those on the low salt diet. Deuterium oxide intake normalized systolic blood pressure and aortic calcium uptake but not aortic rubidium 86 uptake in hypertensive rats on the high salt diet. Deuterium oxide had no effect on blood pressure or aortic calcium uptake in rats on the low salt diet. The parallel increase in systolic blood pressure and vascular calcium uptake suggests that increased calcium uptake mechanisms are associated with hypertension in salt-sensitive Dahl rats. Furthermore, deuterium oxide appears to normalize elevated blood pressure in salt-sensitive hypertensive rats by normalizing elevated vascular (aortic) calcium uptake

  10. The role of uncoupling protein 3 regulating calcium ion uptake into mitochondria during sarcopenia

    Science.gov (United States)

    Nikawa, Takeshi; Choi, Inho; Haruna, Marie; Hirasaka, Katsuya; Maita Ohno, Ayako; Kondo Teshima, Shigetada

    Overloaded mitochondrial calcium concentration contributes to progression of mitochondrial dysfunction in aged muscle, leading to sarcopenia. Uncoupling protein 3 (UCP3) is primarily expressed in the inner membrane of skeletal muscle mitochondria. Recently, it has been reported that UCP3 is associated with calcium uptake into mitochondria. However, the mechanisms by which UCP3 regulates mitochondrial calcium uptake are not well understood. Here we report that UCP3 interacts with HS-1 associated protein X-1 (Hax-1), an anti-apoptotic protein that is localized in mitochondria, which is involved in cellular responses to calcium ion. The hydrophilic sequences within the loop 2, matrix-localized hydrophilic domain of mouse UCP3 are necessary for binding to Hax-1 of the C-terminal domain in adjacent to mitochondrial innermembrane. Interestingly, these proteins interaction occur the calcium-dependent manner. Indeed, overexpression of UCP3 significantly enhanced calcium uptake into mitochondria on Hax-1 endogenously expressing C2C12 myoblasts. In addition, Hax-1 knock-down enhanced calcium uptake into mitochondria on both UCP3 and Hax-1 endogenously expressing C2C12 myotubes, but not myoblasts. Finally, the dissociation of UCP3 and Hax-1 enhances calcium uptake into mitochondria in aged muscle. These studies identify a novel UCP3-Hax-1 complex regulates the influx of calcium ion into mitochondria in muscle. Thus, the efficacy of UCP3-Hax-1 in mitochondrial calcium regulation may provide a novel therapeutic approach against mitochondrial dysfunction-related disease containing sarcopenia.

  11. Glucagon effects on the membrane potential and calcium uptake rate of rat liver mitochondria

    International Nuclear Information System (INIS)

    Wingrove, D.E.; Amatruda, J.M.; Gunter, T.E.

    1984-01-01

    It has been widely reported that the in vivo administration of glucagon to rats results in the stimulation of calcium influx in subsequently isolated liver mitochondria. The mechanism of this effect is investigated through simultaneous measurements of calcium uptake rate and mitochondrial membrane potential. This allows the measurement of the calcium uniporter conductance independent of hormonal effects on electron transport or respiration. Two experimental approaches are used. The first involves measuring the uptake of 40-50 nmol of Ca 2+ /mg of mitochondrial protein with the calcium dye antipyrylazo III; the second uses 45 Ca 2+ to follow uptake in the presence of 0.5 to 1.5 μM free calcium, buffered with HEDTA. In both cases a tetraphenyl phosphonium electrode is used to follow membrane potential, and membrane potential is varied using either malonate or butylmalonate in the presence of rotenone. The relative merits of these two approaches are discussed. The conductance of the calcium uniporter is found not to be stimulated by glucagon pretreatment. Also, the relative glucagon stimulation of both calcium influx and membrane potential is found to increase with increasing malonate concentration. These results imply that there is no direct stimulation of calcium uptake into liver mitochondria following glucagon treatment. The results are consistent with a glucagon stimulation of substrate transport, substrate oxidation, or a stimulation of electron transport resulting in an increased membrane potential and secondary stimulation of calcium uptake

  12. Trpv5/6 is vital for epithelial calcium uptake and bone formation

    NARCIS (Netherlands)

    Vanoevelen, J.; Janssens, A.C.; Huitema, L.F.; Hammond, C.J.; Metz, J.R.; Flik, G.; Voets, T.; Schulte-Merker, S.

    2011-01-01

    Calcium is an essential ion serving a multitude of physiological roles. Aside from its role as a second messenger, it is an essential component of the vertebrate bone matrix. Efficient uptake and storage of calcium are therefore indispensable for all vertebrates. Transient receptor potential family,

  13. Dietary calcium levels and chemical treatments influencing radiostrontium uptake and release in mammalian bones

    International Nuclear Information System (INIS)

    Roushdy, H.M.; Moloukhia, M.K.; Abdel-Fattah, A.T.

    1979-01-01

    Data obtained from in vivo studies on rats suggest that the rate of administered radiostrontium uptake and deposition in bones shows a negative correlation with the levels of dietary calcium in the following order: CR, CN, CP, CDP, where CR stands for calcium-rich diet (Ca% 1.728), CN for calcium-normal ( Ca% 1.442), CP for calcium-poor (Ca% 0.347(and CDP for both calcium-poor (Ca% 0.135) and vitamin D deficient. The uptake values for the administered radiostrontium were affected by the duration of the experimental feeding time in the following order: 10, 50 and 120 days. Administration of MgSO 4 or SrCl 2 experimentally fed animals showed a decrease in the magnitude of radiostrontium uptake, the effect being more pronounced with MgSO, whereas CaCl 2 showed an increase in the rate of uptake of the radionuclide. It has been also found that increasing the level of dietary calcium as well as administration of stable strontium or magnesium favoured more rapid elimination of the radiostrontium from the bones and helped the animals to discriminate more significantly against radiostrontium uptake. The data obtained were statistically evaluated and the results discussed in view of the relevant literature. (author)

  14. Cadmium, zinc and the uptake of calcium by two crabs, Carcinus maenas and Eriocheir sinensis

    International Nuclear Information System (INIS)

    Rainbow, P.S.; Black, W.H.

    2005-01-01

    The uptake of dissolved cadmium and zinc by crustaceans can usually be explained by the passive process of facilitated diffusion involving a transport protein in the membranes of permeable surfaces. Cadmium ions will also enter via uptake routes for calcium, given the similar size of the two free ions. This study has investigated the interaction of cadmium (and comparatively zinc) and calcium uptake in two crabs that show different permeability responses to changes in salinity, with consequently different effects on the uptake of cadmium and zinc with salinity change. Ca uptake rates in Carcinus maenas decreased in reduced salinity (33-15) with the decreased Ca concentration of the medium and increased if the Ca concentration was increased at salinity 20. It is concluded that Ca uptake over the salinity range 33-15 is via apical Ca channels in gill ionocytes, passively down an electrochemical gradient. The Ca uptake rate of Eriocheir sinensis showed no significant decrease over the salinity range 33-10 (probably because of the small differences in an already low Ca uptake rate in this crab against a background of inter-individual variability), but decreased significantly at salinity 5. Added calcium increased the Ca uptake rate of E. sinensis at salinities 15 and 5, supporting the interpretation that Ca uptake in gills is typically passive via apical Ca channels. Cadmium (but not zinc) inhibited calcium uptake in both crabs at 15 salinity, indicating sharing of Ca channels by Cd, but not at salinity 5 (E. sinensis only) when Ca may be taken up into gill ionocytes by another (active?) physiological process

  15. Calcium uptake in aquatic insects: influences of phylogeny and metals (Cd and Zn).

    Science.gov (United States)

    Poteat, Monica D; Buchwalter, David B

    2014-04-01

    Calcium sequestration in the hypo-osmotic freshwater environment is imperative in maintaining calcium homeostasis in freshwater aquatic organisms. This uptake process is reported to have the unintended consequence of potentially toxic heavy metal (Cd, Zn) uptake in a variety of aquatic species. However, calcium uptake remains poorly understood in aquatic insects, the dominant invertebrate faunal group in most freshwater ecosystems. Here, we examined Ca uptake and interactions with heavy metals (Cd, Zn) at low ambient Ca levels (12.5 μmol l(-1)) in 12 aquatic insect species within Ephemerellidae (mayfly) and Hydropsychidae (caddisfly), two families differentially responsive to trace metal pollution. We found Ca uptake varied 70-fold across the 12 species studied. Body mass and clade (family) were found to significantly influence both Ca uptake and adsorption (P≤0.05). Zn and Cd uptake rate constants (ku) exhibited a strong correlation (r=0.96, Pinsects generally differ from other freshwater taxa in that aqueous Ca uptake does not appear to be compromised by Cd or Zn exposure. It is important to understand the trace metal and major ion physiology of aquatic insects because of their ecological importance and widespread use as ecological indicators.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  17. Localised uptake and extraction of calcium45 in dinoflagellate nuclei

    International Nuclear Information System (INIS)

    Sigee, D.C.

    1983-01-01

    The uptake of Ca 45 into cells of the dinoflagellate Glenodinium foliaceum was investigated using insoluble compound light microscope autoradiography. The distribution of silver grains showed marked localisation to the dinocaryotic nucleus, with a random scatter of grains over the surrounding protoplasm (cytoplasm and supernumerary nucleus). Correction of grain counts for lateral sensitisation from the dinocaryotic nucleus indicated an isotope concentration 16 32 times greater in this organelle compared to the rest of the cell. Cells labelled for varying periods of time showed differences in the pattern of Ca 45 uptake throughout the sample populations, but no increase in the mean level of uptake per cell. This would suggest a rapid incorporation of isotope within 1-2 hours, with little subsequent uptake. The presence of high levels of label after processing with both additive (glutaraldehyde, paraformaldehyde) and coagulative (acetic alcohol) fixatives indicated that the retention of Ca 45 in these preparations was not simply a fixation artefact. Although the isotope did not appear to be suitable for (high resolution) electron microscope autoradiography, the intranuclear site of incorporation was demonstrated indirectly using a buffer extraction technique. Prolonged treatment with phosphate buffer resulted in a large scale loss of label from both cytoplasm and dinocaryotic nucleus. The latter appeared to show specific correlation with the loss of (protein) matrix from the chromosomes - as observed under both light and electron microscopy, with no apparent change in either nucleolus or nucleoplasm. This would suggest that incorporated Ca 45 in the nucleus was largely confined to the condensed chromatin, where it was combined with the acidic proteins which make up the bulk of the chromatin matrix. The results obtained in this investigation are related to previous studies involving X-ray microanalysis and uptake of Ni 63 . (Author)

  18. Acetate transiently inhibits myocardial contraction by increasing mitochondrial calcium uptake.

    Science.gov (United States)

    Schooley, James F; Namboodiri, Aryan M A; Cox, Rachel T; Bünger, Rolf; Flagg, Thomas P

    2014-12-09

    There is a close relationship between cardiovascular disease and cardiac energy metabolism, and we have previously demonstrated that palmitate inhibits myocyte contraction by increasing Kv channel activity and decreasing the action potential duration. Glucose and long chain fatty acids are the major fuel sources supporting cardiac function; however, cardiac myocytes can utilize a variety of substrates for energy generation, and previous studies demonstrate the acetate is rapidly taken up and oxidized by the heart. In this study, we tested the effects of acetate on contractile function of isolated mouse ventricular myocytes. Acute exposure of myocytes to 10 mM sodium acetate caused a marked, but transient, decrease in systolic sarcomere shortening (1.49 ± 0.20% vs. 5.58 ± 0.49% in control), accompanied by a significant increase in diastolic sarcomere length (1.81 ± 0.01 μm vs. 1.77 ± 0.01 μm in control), with a near linear dose response in the 1-10 mM range. Unlike palmitate, acetate caused no change in action potential duration; however, acetate markedly increased mitochondrial Ca(2+) uptake. Moreover, pretreatment of cells with the mitochondrial Ca(2+) uptake blocker, Ru-360 (10 μM), markedly suppressed the effect of acetate on contraction. Lehninger and others have previously demonstrated that the anions of weak aliphatic acids such as acetate stimulate Ca(2+) uptake in isolated mitochondria. Here we show that this effect of acetate appears to extend to isolated cardiac myocytes where it transiently modulates cell contraction.

  19. The uptake of uranium and radium from food and water in relation to calcium

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1988-01-01

    Observed ratios for dietary radium and calcium suggest that at least a 20 to 70 fold discrimination exists against radium uptake in the skeleton relative to calcium. It has been widely shown in many countries around the world that the relative radium to calcium ratio in the human skeleton varies from country to country, but within geographic areas, it appears to be relatively invariant with age. The ratio of radium-226 to calcium in intake, relative to the radium-226 to calcium value in the skeleton, is called the observed ratio, and varies over the world from a value of 0.013 to 0.039, with a mean of 0.024. In 1975, I inferred a mean observed ratio for uranium of 0.057 for the US. These findings suggest that man is in equilibrium with radium-226 with respect to the calcium in food and water. Most of the calcium would be ingested in diet, as would a significant amount, but not necessarily all, of the radium. The role of calcium for intake in water has not been examined

  20. Tree species effects on calcium cycling: The role of calcium uptake in deep soils

    NARCIS (Netherlands)

    Dijkstra, F.A.; Smits, M.M.

    2002-01-01

    Soil acidity and calcium (Ca) availability in the surface soil differ substantially beneath sugar maple (Acer saccharum) and eastern hemlock (Tsuga canadensis) trees in a mixed forest in northwestern Connecticut. We determined the effect of pumping of Ca from deep soil (rooting zone below 20-cm

  1. Calcium uptake by cowpea as influenced by mycorrhizal colonization and water stress

    International Nuclear Information System (INIS)

    Pai, G.; Bagyaraj, D.J.; Padmavathi Ravindra, T.; Prasad, T.G.

    1994-01-01

    The role of vesicular-arbuscular mycorrhizal (VAM) colonization on calcium uptake was studied under different levels of moisture stress. Pots maintained at different moisture levels were given water containing known amount of radioactive calcium. The radioactivity in different parts of the plant was assessed 60 h after giving 45 Ca to the soil. High 45 Ca activity was present in all parts of vesicular-arbuscular mycrrohizal (VAM) plants compared to non-mycorrhizal plants at all levels of moisture stress. (author). 14 refs., 1 tab

  2. Effects of calcium antagonists on isolated bovine cerebral arteries: inhibition of constriction and calcium-45 uptake induced by potassium or serotonin

    International Nuclear Information System (INIS)

    Wendling, W.W.; Harakal, C.

    1987-01-01

    The purpose of this study was to determine the mechanisms by which organic calcium channel blockers inhibit cerebral vasoconstriction. Isolated bovine middle cerebral arteries were cut into rings to measure contractility or into strips to measure radioactive calcium ( 45 Ca) influx and efflux. Calcium channel blockers (10(-5) M verapamil or 3.3 X 10(-7) M nifedipine) and calcium-deficient solutions all produced near-maximal inhibition of both potassium- and serotonin-induced constriction. In calcium-deficient solutions containing potassium or serotonin, verapamil and nifedipine each blocked subsequent calcium-induced constriction in a competitive manner. Potassium and serotonin significantly increased 45 Ca uptake into cerebral artery strips during 5 minutes of 45 Ca loading; for potassium 45 Ca uptake increased from 62 to 188 nmol/g, and for serotonin from 65 to 102 nmol/g. Verapamil or nifedipine had no effect on basal 45 Ca uptake but significantly blocked the increase in 45 Ca uptake induced by potassium or serotonin. Potassium, and to a lesser extent serotonin, each induced a brief increase in the rate of 45 Ca efflux into calcium-deficient solutions. Verapamil or nifedipine had no effect on basal or potassium-stimulated 45 Ca efflux. The results demonstrate that verapamil and nifedipine block 45 Ca uptake through both potential-operated (potassium) and receptor-operated (serotonin) channels in bovine middle cerebral arteries

  3. β-endorphin modulation of mitogen-stimulated calcium uptake by rat thymocytes

    International Nuclear Information System (INIS)

    Hemmick, L.M.; Bidlack, J.M.

    1987-01-01

    Lymphocytes stimulated by mitogens or antigens exhibit an enhanced calcium uptake early in the proliferation or activation response. Modulation of this calcium uptake results in alterations of proliferation and immunocompetence. β-endorphin and other opioids affect several parameters of lymphocyte competence. Limited data are available concerning the mechanism(s) of these effects. This study examines whether a possible opioid mechanism is the modification of the early calcium influx into stimulated lymphocytes. The time course of both concanavalin A (Con A) and phytohemagglutinin (PHA)-stimulated 45 Ca 2+ uptake into thymocytes was characterized to determine the optimal time for testing the effects of opioids. Β-Endorphin 1-31 significantly enhanced Con A-stimulated 45 Ca 2+ uptake into rat thymocytes. This peptide had no significant effect on PHA-simulated 45 Ca 2+ uptake or on basal thymocyte 45 Ca 2+ flux. The β/sub h/-endorphin stimulatory effect was titratable in the range of 0.1 nM to 10 μM. Naloxone did not reverse the enhancement. Met-enkephalinamide and other opioid agonists did not duplicate the stimulatory effect. Thus, the β/sub h/-endorphin 1-31 enhancement of Con A-stimulated 45 Ca 2+ uptake by rat thymocytes does not operate via classical opioid receptor mechanisms. β/sub h/-endorphin 1-31 appears to be acting on a subset of T cells that are responsive to Con A but not to PHA. 30 references, 4 figures, 1 table

  4. beta. -endorphin modulation of mitogen-stimulated calcium uptake by rat thymocytes

    Energy Technology Data Exchange (ETDEWEB)

    Hemmick, L.M.; Bidlack, J.M.

    1987-10-19

    Lymphocytes stimulated by mitogens or antigens exhibit an enhanced calcium uptake early in the proliferation or activation response. Modulation of this calcium uptake results in alterations of proliferation and immunocompetence. ..beta..-endorphin and other opioids affect several parameters of lymphocyte competence. Limited data are available concerning the mechanism(s) of these effects. This study examines whether a possible opioid mechanism is the modification of the early calcium influx into stimulated lymphocytes. The time course of both concanavalin A (Con A) and phytohemagglutinin (PHA)-stimulated /sup 45/Ca/sup 2 +/ uptake into thymocytes was characterized to determine the optimal time for testing the effects of opioids. BETA-Endorphin 1-31 significantly enhanced Con A-stimulated /sup 45/Ca/sup 2 +/ uptake into rat thymocytes. This peptide had no significant effect on PHA-simulated /sup 45/Ca/sup 2 +/ uptake or on basal thymocyte /sup 45/Ca/sup 2 +/ flux. The ..beta../sub h/-endorphin stimulatory effect was titratable in the range of 0.1 nM to 10 ..mu..M. Naloxone did not reverse the enhancement. Met-enkephalinamide and other opioid agonists did not duplicate the stimulatory effect. Thus, the ..beta../sub h/-endorphin 1-31 enhancement of Con A-stimulated /sup 45/Ca/sup 2 +/ uptake by rat thymocytes does not operate via classical opioid receptor mechanisms. ..beta../sub h/-endorphin 1-31 appears to be acting on a subset of T cells that are responsive to Con A but not to PHA. 30 references, 4 figures, 1 table.

  5. Uptake of calcium-45 by apple trees at different levels of moisture in relation to the occurrence of bitter pit

    International Nuclear Information System (INIS)

    Hanekom, A.N.; Deist, J.; Blommaert, K.L.J.

    1975-01-01

    Uptake and translocation of recently absorbed Ca ( 45 Ca) and total calcium by Golden Delicious apple trees grown in sand culture at different moisture levels were investigated in relation to bitter pit. Growth and development of the trees were significantly retarded by low moisture supply. Moisture stress not only lowered calcium uptake and/or translocation but also significantly decreased the concentration of recently absorbed calcium in the different parts of the tree. Except for the leaves where moisture stress significantly decreased the total calcium concentration, it did not affect the concentration in other parts of the tree. Although the fruit contributed only 5,8% to the total calcium content of the top parts of the tree, this amount of Ca realised a sufficiently high calcium concentration in the fruit to prevent bitter pit. There was no correlation within the experimental period between moisture supply to the trees and the calcium concentration in the fruit or the incidence of bitter pit [af

  6. A protective effect of dietary calcium against acute waterborne cadmium uptake in rainbow trout

    International Nuclear Information System (INIS)

    Baldisserotto, B.; Kamunde, C.; Matsuo, A.; Wood, C.M.

    2004-01-01

    The present study examined the interactions between elevated dietary calcium (as ionic Ca 2+ in the form of CaCl 2 ·2H 2 O) and acute waterborne Cd exposure (50 μg/l as CdNO 3 for 3 h) on whole body uptake and internal distribution of newly accumulated Cd, Ca 2+ , and Na + in juvenile rainbow trout (Oncorhynchus mykiss). Fish were fed with three diets 20 (control), 30 and 60 mg Ca 2+ /g food: for 7 days before fluxes were measured with radiotracers over a 3 h period. The two elevated Ca 2+ diets reduced the whole body uptake of both Ca 2+ and Cd by >50% and similarly reduced the internalization of both newly accumulated metals in most tissues, effects which reflect the shared branchial uptake route for Ca 2+ and Cd. As the Ca 2+ concentrations of the fluid phases of the stomach and intestinal contents were greatly elevated by the experimental diets, increased gastrointestinal Ca 2+ uptake likely caused the down-regulation of the branchial Ca 2+ (and Cd) uptake pathway. Waterborne Na + uptake and internal distribution were not affected. While plasma Ca 2+ surged after the first two feedings of the 60 mg Ca 2+ /g diet, internal homeostasis was quickly restored. Total Ca 2+ , Na + , and Cl - levels in tissues were not affected by diets. While dietary Ca 2+ protected against waterborne Cd uptake, it did not protect against the relative inhibition of waterborne Ca 2+ uptake caused by waterborne Cd. Acute exposure to 50 μg/l Cd reduced the uptake and internalization of newly accumulated Ca 2+ (but not Na + ) by 70% or more, regardless of diet. Since elevated dietary Ca 2+ reduces waterborne Cd uptake, fish eating a Ca 2+ -rich invertebrate diet may be more protected against waterborne Cd toxicity in a field situation

  7. Effects of antibiotics on uptake of calcium into isolated nerve terminals

    International Nuclear Information System (INIS)

    Atchison, W.D.; Adgate, L.; Beaman, C.M.

    1988-01-01

    The goal of the present study was to determine whether several antibiotics which are known to block neuromuscular transmission would impair depolarization-dependent and/or -independent uptake of calcium into isolated nerve terminals prepared from forebrain synaptosomes of rats by conventional methods. Antibiotics tested for potential block of Ca++ uptake included the aminoglycosides neomycin and streptomycin, the lincosamide clindamycin, oxytetracycline and polymyxin B. Drugs were applied in concentrations ranging from 1 to 1000 microM. Uptake of 45Ca was determined during depolarization induced by an elevated K+ concentration (77.5 mM). Influxes of 45Ca during 1 and 10 sec of depolarization were used to assess Ca++ uptake via a fast, inactivating path and total uptake, respectively. Uptake of 45Ca during 10 sec of depolarization into synaptosomes which were previously depolarized for 10 sec in the presence of 77.5 mM K+ but in the absence of external Ca++ was used to measure uptake during a slow, noninactivating path. Total depolarization-dependent uptake of 45Ca was depressed significantly by all antibiotics tested except oxytetracycline; however, the various agents differed with respect to their efficacy and potency as blockers of Ca influx. The fast component of uptake, which is thought to be associated with neurotransmitter release, was decreased significantly by all antibiotics. Neomycin and polymyxin were the most potent and most effective at lowering fast phase 45Ca influx; streptomycin, was intermediate in effectiveness whereas clindamycin and oxytetracycline were only effective at concentrations greater than or equal to 100 microM. Only clindamycin, streptomycin and polymyxin B caused significant reductions in the slow phase of 45Ca uptake

  8. Calcium uptake by sarcoplasmic reticulum in the presence of organophosphorus insecticide methyl-parathion

    International Nuclear Information System (INIS)

    Blasiak, J.

    1995-01-01

    Using an isotope labelling technique it has been shown that an organophosphorus insecticide methyl parathion (0,0-diethyl 0-4-nitrophenyl phosphorothionate) depressed calcium uptake by sarcoplasmic reticulum isolated from rabbit hind leg muscle. The effect was significant for insecticide concentrations of 50 and 100 μM and was dose-dependent. The insecticide exerted a more pronounced effect on calcium uptake in the presence of ATP in the reticulum environment than in the absence of ATP. The inhibitory action of methyl parathion on Ca 2+ accumulation by sarcoplasmic reticulum can cause a rise in myoplasmic free Ca 2+ , the essential prerequisite for contracture activation. Because methyl parathion, as well as other organophosphorus insecticides, is primarily neurotoxic, evidence of non-specific effect could be important for assessing its environmental safety. (author). 20 refs, 2 figs

  9. Dopamine receptors on adrenal chromaffin cells modulate calcium uptake and catecholamine release

    Energy Technology Data Exchange (ETDEWEB)

    Bigornia, L; Suozzo, M; Ryan, K A; Napp, D; Schneider, A S

    1988-10-01

    The presence of dopamine-containing cells in sympathetic ganglia, i.e., small, intensely fluorescent cells, has been known for some time. However, the role of dopamine as a peripheral neurotransmitter and its mechanism of action are not well understood. Previous studies have demonstrated the presence of D2 dopamine receptors on the surface of bovine adrenal chromaffin cells using radioligand binding methods and dopamine receptor inhibition of catecholamine release from perfused adrenal glands. In the present study, we provide evidence confirming a role of dopamine receptors as inhibitory modulators of adrenal catecholamine release from bovine chromaffin cell cultures and further show that the mechanism of modulation involves inhibition of stimulated calcium uptake. Apomorphine gave a dose-dependent inhibition (IC50 = 1 microM) of 45Ca2+ uptake stimulated by either nicotine (10 microM) or membrane depolarization with an elevated K+ level (60 mM). This inhibition was reversed by a series of specific (including stereospecific) dopamine receptor antagonists: haloperidol, spiperone, sulpiride, and (+)-butaclamol, but not (-)-butaclamol. In addition, the calcium channel agonist Bay K 8644 was used to stimulate uptake of 45Ca2+ into chromaffin cells, and this uptake was also inhibited by the dopamine receptor agonist apomorphine. The combined results suggest that dopamine receptors on adrenal chromaffin cells alter Ca2+ channel conductance, which, in turn, modulates catecholamine release.

  10. Effect of EHDP on calcium accumulation and technetium-99m pyrophosphate uptake in experimental myocardial infarction

    International Nuclear Information System (INIS)

    Buja, L.M.; Tofe, A.J.; Parkey, R.W.; Francis, M.D.; Lewis, S.E.; Kulkarni, P.V.; Bonte, F.J.; Willerson, J.T.

    1981-01-01

    Ethane-l-hydroxy-1,1-diphosphonate (EHDP) inhibits bone mineral growth. This study was performed to test the hypothesis that EHDP would interfere with the process of calcium uptake and deposition in evolving myocardial infarction and thereby influence other parameters, including technetium-99m pyrophosphate (Tc-99m PYP) uptake and scintigraphic visualization of the infarcts. Permanent occlusion of the left anterior descending coronary artery (LAD) was produced in beagles. In seven dogs, serum EHDP was maintained at 10-15 μg/ml for 24 hours by continuous i.v. infusion, and seven control dogs were infused with saline. The Tc-99m PYP was infected 2 hours before sacrifice. EHDP-treated dogs showed a mild decrease (20%) in mean calcium content of infarcted myocardium (102.4 +/- 6.4 μg [+/- SEM] per gram wet weight [n = 51] vs 126.7 +/- 9.5 [n = 49] [p -3 ] [n = 46] vs 28.9 +/- 4.3 [n = 46] [p < 0.005]) and a marked decrease (65%) in infarct-to-normal ratio (6.1 +/- 0.9 [n = 6] vs 15.9 +/- 3.7 [n = 6] [p < 0.05]). Positive relationships were demonstrated between myocardial Tc-99m PYP and calcium levels in the EHDP-treated dogs (r = 0.69) and the control dogs (r = 0.77). Infarct size and regional myocardial blood flow changes were similar in the EHDP-treated and control dogs. The average grade (0-4+) of the Tc-99m PYP myocardial scintigrams for infarcts greater than 3.5 g was 2.4 +/- 0.2 for control dogs and 1.1 +/- 0.4 for EHDP-treated dogs (p < 0.05). Thus, EHDP infusion at the dose tested produced a mild decrease in calcium accumulation in canine infarcts; however, it produced a greater reduction in Tc-99m PYP uptake in the infarcts

  11. 3-Bromopyruvate inhibits calcium uptake by sarcoplasmic reticulum vesicles but not SERCA ATP hydrolysis activity.

    Science.gov (United States)

    Jardim-Messeder, Douglas; Camacho-Pereira, Juliana; Galina, Antonio

    2012-05-01

    3-Bromopyruvate (3BrPA) is an antitumor agent that alkylates the thiol groups of enzymes and has been proposed as a treatment for neoplasias because of its specific reactivity with metabolic energy transducing enzymes in tumor cells. In this study, we show that the sarco/endoplasmic reticulum calcium (Ca(2+)) ATPase (SERCA) type 1 is one of the target enzymes of 3BrPA activity. Sarco/endoplasmic reticulum vesicles (SRV) were incubated in the presence of 1mM 3BrPA, which was unable to inhibit the ATPase activity of SERCA. However, Ca(2+)-uptake activity was significantly inhibited by 80% with 150 μM 3BrPA. These results indicate that 3BrPA has the ability to uncouple the ATP hydrolysis from the calcium transport activities. In addition, we observed that the inclusion of 2mM reduced glutathione (GSH) in the reaction medium with different 3BrPA concentrations promoted an increase in 40% in ATPase activity and protects the inhibition promoted by 3BrPA in calcium uptake activity. This derivatization is accompanied by a decrease of reduced cysteine (Cys), suggesting that GSH and 3BrPA increases SERCA activity and transport by pyruvylation and/or S-glutathiolation mediated by GSH at a critical Cys residues of the SERCA. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Uptake of radioactive strontium by fishes in relation to the calcium content of the water

    International Nuclear Information System (INIS)

    Chiosila, J.

    1975-01-01

    The study attempts to compare experimental results obtained with pseudorasbora parava with regard to 85 Sr uptake at various Ca concentrations of the water (4.20 and 50 mg/l Ca) and also to compare these results with natural conditions. The water was contaminated with 500 pCi/ml 85 SrCl 2 only at the onset of the experiments. Radiostrontium uptake is much higher with a very low calcium content of the water; maximum values are reached in about 10 days. - With low or optimum calcium contents of the water, the values are 3-5 times lower and are not reached until 30 days after radioactive contamination. The fish in this Danube water experiment took up somewhat less radioactivity than in an experiment with the same amounts of Ca and Mg in a control medium. The uptake of 85 Sr in fish in dependence of the Ca content of the water varies according to the formula F.C = 2.505 x Casup(-0.909), with Ca given in Mg/l. (orig.) [de

  13. Effect of Calcium Levels on Strontium Uptake by Canola Plants Grown on Different Texture Soils

    International Nuclear Information System (INIS)

    El-Shazly, A.A.; Rezk, M. A.; Abdel-Sabour, M.F.; Mousa, E.A.; Mostafa, M.A.Z.; Lotfy, S.M.; Farid, I.M.; Abbas, M.H.H.; Abbas, H.H.

    2016-01-01

    Canola is considered aphytoremediator where, it can remove adequate quantities of heavy metals when grown on polluted soils.This study aimed to investigate growth performance of canola plants grown on clayey non-calcareous, sandy non-calcareous and sandy clay loam calcareous soils with different CaCO 3 contents. These soils were artificially contaminated with 100 mg Sr kg -1 and cultivated with canola plants under three levels of applied calcium i.e. 0, 60 and 85 mg Ca kg -1 in the form of CaCl 2 . The grown plants were kept under the green house conditions until (pot experiment) maturity. Afterwards, plants were harvested, separated into shoots, roots and seeds, and analyzed for their contents of calcium and strontium. Application of calcium to the sandy soil increased Ca uptake by canola plants whereas, Sr uptake, plant growth and seed yield were reduced. In the other soils, Ca and Sr uptake values were increased with minimized Ca rate. Such increases were associated with significant increases in the plant biomass and crop yield in the clayey soil; whereas, in the sandy clay loam calcareous soil, such increases were insignificant. Increasing the dose of the applied Ca (its higher rate) was associated with significant reduction in the plant growth and seed yield in these two soils. Both the biological concentration factor and the biological accumulation factors were relatively high (>1). The biological transfer factor was also high indicating high translocation of Sr from root to shoot. However, Sr translocation decreased with Ca applications. Accordingly canola plants are highly recommended for phytoextraction of Sr from polluted soils

  14. A protective effect of dietary calcium against acute waterborne cadmium uptake in rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Baldisserotto, B.; Kamunde, C.; Matsuo, A.; Wood, C.M

    2004-03-30

    The present study examined the interactions between elevated dietary calcium (as ionic Ca{sup 2+} in the form of CaCl{sub 2}{center_dot}2H{sub 2}O) and acute waterborne Cd exposure (50 {mu}g/l as CdNO{sub 3} for 3 h) on whole body uptake and internal distribution of newly accumulated Cd, Ca{sup 2+}, and Na{sup +} in juvenile rainbow trout (Oncorhynchus mykiss). Fish were fed with three diets 20 (control), 30 and 60 mg Ca{sup 2+}/g food: for 7 days before fluxes were measured with radiotracers over a 3 h period. The two elevated Ca{sup 2+} diets reduced the whole body uptake of both Ca{sup 2+} and Cd by >50% and similarly reduced the internalization of both newly accumulated metals in most tissues, effects which reflect the shared branchial uptake route for Ca{sup 2+} and Cd. As the Ca{sup 2+} concentrations of the fluid phases of the stomach and intestinal contents were greatly elevated by the experimental diets, increased gastrointestinal Ca{sup 2+} uptake likely caused the down-regulation of the branchial Ca{sup 2+} (and Cd) uptake pathway. Waterborne Na{sup +} uptake and internal distribution were not affected. While plasma Ca{sup 2+} surged after the first two feedings of the 60 mg Ca{sup 2+}/g diet, internal homeostasis was quickly restored. Total Ca{sup 2+}, Na{sup +}, and Cl{sup -} levels in tissues were not affected by diets. While dietary Ca{sup 2+} protected against waterborne Cd uptake, it did not protect against the relative inhibition of waterborne Ca{sup 2+} uptake caused by waterborne Cd. Acute exposure to 50 {mu}g/l Cd reduced the uptake and internalization of newly accumulated Ca{sup 2+} (but not Na{sup +}) by 70% or more, regardless of diet. Since elevated dietary Ca{sup 2+} reduces waterborne Cd uptake, fish eating a Ca{sup 2+}-rich invertebrate diet may be more protected against waterborne Cd toxicity in a field situation.

  15. Uptake of the proteins HTRA1 and HTRA2 by cells mediated by calcium phosphate nanoparticles

    Directory of Open Access Journals (Sweden)

    Olga Rotan

    2017-02-01

    Full Text Available The efficient intracellular delivery of (biomolecules into living cells remains a challenge in biomedicine. Many biomolecules and synthetic drugs are not able to cross the cell membrane, which is a problem if an intracellular mode of action is desired, for example, with a nuclear receptor. Calcium phosphate nanoparticles can serve as carriers for small and large biomolecules as well as for synthetic compounds. The nanoparticles were prepared and colloidally stabilized with either polyethyleneimine (PEI; cationic nanoparticles or carboxymethyl cellulose (CMC; anionic nanoparticles and loaded with defined amounts of the fluorescently labelled proteins HTRA1, HTRA2, and BSA. The nanoparticles were purified by ultracentrifugation and characterized by dynamic light scattering and scanning electron microscopy. Various cell types (HeLa, MG-63, THP-1, and hMSC were incubated with fluorescently labelled proteins alone or with protein-loaded cationic and anionic nanoparticles. The cellular uptake was followed by light and fluorescence microscopy, confocal laser scanning microscopy (CLSM, and flow cytometry. All proteins were readily transported into the cells by cationic calcium phosphate nanoparticles. Notably, only HTRA1 was able to penetrate the cell membrane of MG-63 cells in dissolved form. However, the application of endocytosis inhibitors revealed that the uptake pathway was different for dissolved HTRA1 and HTRA1-loaded nanoparticles.

  16. Calcium uptake by sarcoplasmic reticulum isolated from hearts of septic rats

    International Nuclear Information System (INIS)

    McDonough, K.H.

    1988-01-01

    Myocardial sarcoplasmic reticulum (SR) plays a critical role in the regulation of the cytosolic calcium fluctuations that occur during the cardiac cycle. One function of the SR is to lower the calcium concentration so that myocardial relaxation and thus ventricular filling can occur. The aim of the present study was to determine if hyperdynamic sepsis induced a decrease in the capacity of SR to take up calcium. This defect would result in decreased ventricular filling and thus decreased cardiac output, as has previously been shown in isolated perfused working hearts removed from septic rats. Therefore, rats were anesthetized with ether, and sepsis was induced by the injection of an aliquot of a fecal homogenate into the peritoneal cavity. Control animals either underwent surgery and received an aliquot of sterilized fecal inoculum (sham) or were untreated (no surgery). On day 2 after surgery, animals were anesthetized with pentobarbital, and hearts were removed, weighted, and SR isolated. The rate of uptake of 45 Ca 2+ by SR from septic rats was not depressed compared to controls but in fact was elevated. Maximum 45 Ca 2+ accumulated by the SR and Ca 2+ -stimulated ATPase activity were similar in SR from control and septic hearts. These results suggest that the contractile dysfunction noted in the myocardium in early sepsis is probably not due to inadequate SR removal of Ca 2+ during diastole

  17. Inhibition of calcium uptake during hypoxia in developing zebrafish is mediated by hypoxia-inducible factor.

    Science.gov (United States)

    Kwong, Raymond W M; Kumai, Yusuke; Tzaneva, Velislava; Azzi, Estelle; Hochhold, Nina; Robertson, Cayleih; Pelster, Bernd; Perry, Steve F

    2016-12-15

    The present study investigated the potential role of hypoxia-inducible factor (HIF) in calcium homeostasis in developing zebrafish (Danio rerio). It was demonstrated that zebrafish raised in hypoxic water (30 mmHg; control, 155 mmHg P O 2 ) until 4 days post-fertilization exhibited a substantial reduction in whole-body Ca 2+ levels and Ca 2+ uptake. Ca 2+ uptake in hypoxia-treated fish did not return to pre-hypoxia (control) levels within 2 h of transfer back to normoxic water. Results from real-time PCR showed that hypoxia decreased the whole-body mRNA expression levels of the epithelial Ca 2+ channel (ecac), but not plasma membrane Ca 2+ -ATPase (pmca2) or Na + /Ca 2+ -exchanger (ncx1b). Whole-mount in situ hybridization revealed that the number of ecac-expressing ionocytes was reduced in fish raised in hypoxic water. These findings suggested that hypoxic treatment suppressed the expression of ecac, thereby reducing Ca 2+ influx. To further evaluate the potential mechanisms for the effects of hypoxia on Ca 2+ regulation, a functional gene knockdown approach was employed to prevent the expression of HIF-1αb during hypoxic treatment. Consistent with a role for HIF-1αb in regulating Ca 2+ balance during hypoxia, the results demonstrated that the reduction of Ca 2+ uptake associated with hypoxic exposure was not observed in fish experiencing HIF-1αb knockdown. Additionally, the effects of hypoxia on reducing the number of ecac-expressing ionocytes was less pronounced in HIF-1αb-deficient fish. Overall, the current study revealed that hypoxic exposure inhibited Ca 2+ uptake in developing zebrafish, probably owing to HIF-1αb-mediated suppression of ecac expression. © 2016. Published by The Company of Biologists Ltd.

  18. Calcium uptake and release by isolated cortices and microsomes from the unfertilized egg of the sea urchin strongylocentrotus droebachiensis

    International Nuclear Information System (INIS)

    Oberdorf, J.A.

    1986-01-01

    Two subcellular fractions of the sea urchin egg were studied for their potential role in regulating the transient rise in cytosolic calcium that accompanies fertilization. Isolated cortices from unfertilized sea urchin eggs sequester calcium in an ATP dependent manner when incubated in a medium containing free calcium levels characteristic of the resting cell. This ATP dependent calcium uptake activity, measured in the presence of 5mM Na Azide to prevent mitochondrial accumulation, was increased by oxalate, and was blocked by 150 μM quercetin and 50 μM vanadate. Cortices preloaded with 45 Ca in the presence of ATP dramatically increased their rate of calcium efflux upon the addition of (1) the calcium ionophore A23187 (10 μM), (2) trifluoperazine (200 μM), (3) concentrations of free calcium that activated cortical granule exocytosis, and (4) the calcium mobilizing agent inositol trisphosphate (IP3). This pool of calcium is most likely sequestered in the portion of the egg's endoplasmic reticulum (ER) that remains associated with the cortical region during its isolation. They have developed a method for obtaining a high yield of purified microsomal vesicles from whole eggs. This preparation also demonstrates ATP dependent calcium sequestering activity which increases in the presence of oxalate and has similar sensitivities to calcium transport inhibitors, however the isolated microsomal vesicles did not show any detectable release of calcium when exposed to IP3. Procedures originally developed for purifying calsequestrin were used to partially purify a 58,000 MW protein from the egg's microsomal vesicles

  19. Prediction of coronary artery calcium progression by FDG uptake of large arteries in asymptomatic individuals

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sang-Geon; Park, Ki Seong; Kim, Jahae; Song, Ho-Chun [Chonnam National University Hospital, Department of Nuclear Medicine, Gwang-ju (Korea, Republic of); Kang, Sae-Ryung; Kwon, Seong Young; Jabin, Zeenat; Kim, Young Jae; Jeong, Geum-Cheol; Song, Minchul; Min, Jung-Joon; Bom, Hee-Seung [Chonnam National University Hwasun Hospital, Department of Nuclear Medicine, Hwasun-gun, Jeollanam-do (Korea, Republic of); Seon, Hyun Ju [Chonnam National University Hwasun Hospital, Department of Radiology, Hwasun-gun, Jeollanam-do (Korea, Republic of)

    2017-01-15

    The purpose of this study is to evaluate whether fluorodeoxyglucose (FDG) uptake of the large arteries can predict coronary artery calcium (CAC) progression in asymptomatic individuals. Ninety-six asymptomatic individuals who underwent FDG positron emission tomography (PET) and CAC scoring on the same day for health screening and follow-up CAC scoring ≥1 year after baseline studies (mean 4.3 years) were included. Vascular FDG uptake was measured and corrected for blood pool activity to obtain peak and average target-to-blood pool ratios (TBRpeak and TBRavg, respectively) for the carotid arteries, and ascending and abdominal aorta. CAC scores at baseline and follow-up of each individual were measured and absolute CAC change (ΔCAC), annual CAC change (ΔCAC/year), and annual CAC change rate (ΔCAC%/year) were calculated. CAC progression was defined as ΔCAC >0 for individuals with negative baseline CAC; ΔCAC/year ≥10 for those with baseline CAC of 0uptake and other clinical risk factors were compared between CAC-progressors and non-CAC-progressors. Multivariate analysis was performed to evaluate whether vascular FDG uptake can independently predict CAC progression. Thirty-one subjects showed CAC progression. CAC-progressors showed significantly higher TBRpeak and TBRavg as compared to non-CAC-progressors for all three arteries. TBRpeak of the abdominal aorta was significantly associated with CAC progression in multivariate analysis, with age and baseline CAC. A higher TBRpeak of the abdominal aorta (≥2.11) was associated with CAC progression among subjects with negative baseline CAC only. In subjects with positive baseline CAC, only the amount of baseline CAC was significantly associated with CAC progression. However, the positive predictive value of the TBRpeak of the abdominal aorta was <40 % when age was <58 or baseline CAC was negative. Higher FDG uptake of the large arteries is

  20. Influence of extra-cellular and intra-cellular acting thiol oxidants on the 45calcium uptake by the islets of Langerhans of the rat

    International Nuclear Information System (INIS)

    Haegele, R.G.

    1981-01-01

    The glucose-stimulated calcium uptake by the islets of Langerhans is dependent on the intra-cellular GSH/GSSG ratios. The inhibition of calcium uptake is not the consequence of a direct oxidation of membrane-fixed thiol groups. In contrast, direct oxidation of extra cellular thiols leads to an increase in calcium uptake when intra-cellular oxidation is simultaneously prevented. Since this effect only occurs at high intra-cellular GSH/GSSG ratios it can be assumed that the redox state of extra-cellular thiols is dependent on the redox state of the intra-cellular GSH/GSSG ratios. These findings support the theory that the oxidation of extra-cellular thiols by thiol oxidants leads to an increase in calcium uptake and that the extent of uptake is higher, the more the redox state of the extra-cellular thiols tends towards the reduced state prior to oxidation. (orig./MG) [de

  1. Effects of spontaneously hypertensive rat plasma on blood pressure and tail artery calcium uptake in normotensive rats

    International Nuclear Information System (INIS)

    Lewanczuk, R.Z.; Wang, J.; Zhang, Z.R.; Pang, P.K.

    1989-01-01

    Previous studies have described the presence of humoral hypertensive factors in spontaneously hypertensive rats (SHR). Other studies have described factors that increase calcium uptake in vascular tissue. In this study, we attempted to confirm, and thereby correlate, the presence of both types of factors in SHR plasma. Intravenous infusion or bolus administration of dialyzed SHR plasma consistently induced an increase in blood pressure in normotensive rats. This hypertensive response was somewhat delayed, with peak blood pressures occurring 45 minutes after bolus administration and 90 minutes after infusion of SHR plasma. Spontaneously hypertensive rat plasma also increased 45 Ca uptake in isolated normotensive rat tail arteries in a dose-dependent manner, with a time course similar to that for the hypertensive response to bolus administration. These findings suggest, therefore, that a substance exists in SHR plasma that can increase intracellular calcium in vascular tissues and thereby increase blood pressure

  2. Effect of sepsis on calcium uptake and content in skeletal muscle and regulation in vitro by calcium of total and myofibrillar protein breakdown in control and septic muscle: Results from a preliminary study

    International Nuclear Information System (INIS)

    Benson, D.W.; Hasselgren, P.O.; Hiyama, D.T.; James, J.H.; Li, S.; Rigel, D.F.; Fischer, J.E.

    1989-01-01

    Because high calcium concentration in vitro stimulates muscle proteolysis, calcium has been implicated in the pathogenesis of increased muscle breakdown in different catabolic conditions. Protein breakdown in skeletal muscle is increased during sepsis, but the effect of sepsis on muscle calcium uptake and content is not known. In this study the influence of sepsis, induced in rats by cecal ligation and puncture, on muscle calcium uptake and content was studied. Sixteen hours after cecal ligation and puncture or sham operation, calcium content of the extensor digitorum longus (EDL) and soleus (SOL) muscles was determined with an atomic absorption spectrometer. Calcium uptake was measured in intact SOL muscles incubated in the presence of calcium 45 (45Ca) for between 1 and 120 minutes. Total and myofibrillar protein breakdown was determined in SOL muscles, incubated in the presence of different calcium concentrations (0; 2.5; 5.0 mmol/L), and measured as release into the incubation medium of tyrosine and 3-methylhistidine (3-MH), respectively. Calcium content was increased by 51% (p less than 0.001) during sepsis in SOL and by 10% (p less than 0.05) in EDL muscle. There was no difference in 45Ca uptake between control and septic muscles during the early phase (1 to 5 minutes) of incubation. During more extended incubation (30 to 120 minutes), muscles from septic rats took up significantly more 45Ca than control muscles (p less than 0.05). Tyrosine release by incubated SOL muscles from control and septic rats was increased when calcium was added to the incubation medium, and at a calcium concentration of 2.5 mmol/L, the increase in tyrosine release was greater in septic than in control muscle. Addition of calcium to the incubation medium did not affect 3-MH release in control or septic muscle

  3. Calcium

    Science.gov (United States)

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

  4. Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings (Zea mays L.).

    Science.gov (United States)

    Zhao, Xiulan; Wang, Dingyong

    2010-01-01

    Mercury (Hg) contents in ten chemical fertilizers were determined, and the effect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously influence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously influence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coefficient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils.

  5. Cellular uptake of {sup 99m}TcN-NOET in human leukaemic HL-60 cells is related to calcium channel activation and cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Guillermet, Stephanie; Vuillez, Jean-Philippe; Caravel, Jean-Pierre; Marti-Batlle, Daniele; Fagret, Daniel [Universite de Grenoble, Radiopharmaceutiques Biocliniques, La Tronche (France); Fontaine, Eric [Universite de Grenoble, Laboratoire de Bioenergetique Fondamentale et Appliquee, Grenoble (France); Pasqualini, Roberto [Cis Bio International Schering SA, Gif-sur-Yvette (France)

    2006-01-01

    A major goal of nuclear oncology is the development of new radiolabelled tracers as proliferation markers. Intracellular calcium waves play a fundamental role in the course of the cell cycle. These waves occur in non-excitable tumour cells via store-operated calcium channels (SOCCs). Bis(N-ethoxy, N-ethyldithiocarbamato) nitrido technetium (V)-99m ({sup 99m}TcN-NOET) has been shown to interact with L-type voltage-operated calcium channels (VOCCs) in cultured cardiomyocytes. Considering the analogy between VOCCs and SOCCs, we sought to determine whether {sup 99m}TcN-NOET also binds to activated SOCCs in tumour cells in order to clarify the potential value of this tracer as a proliferation marker. Uptake kinetics of {sup 99m}TcN-NOET were measured in human leukaemic HL-60 cells over 60 min and the effect of several calcium channel modulators on 1-min tracer uptake was studied. The uptake kinetics of {sup 99m}TcN-NOET were compared both with the variations of cytosolic free calcium concentration measured by indo-1/AM and with the variations in the SG{sub 2}M cellular proliferation index. All calcium channel inhibitors significantly decreased the cellular uptake of {sup 99m}TcN-NOET whereas the activator thapsigargin induced a significant 10% increase. In parallel, SOCC activation by thapsigargin, as measured using the indo-1/AM probe, was inhibited by nicardipine. These results indicate that the uptake of {sup 99m}TcN-NOET is related to the activation of SOCCs. Finally, a correlation was observed between the tracer uptake and variations in the proliferation index SG{sub 2}M. The uptake of {sup 99m}TcN-NOET seems to be related to SOCC activation and to cell proliferation in HL-60 cells. These results indicate that {sup 99m}TcN-NOET might be a marker of cell proliferation. (orig.)

  6. Cellular uptake of 99mTcN-NOET in human leukaemic HL-60 cells is related to calcium channel activation and cell proliferation

    International Nuclear Information System (INIS)

    Guillermet, Stephanie; Vuillez, Jean-Philippe; Caravel, Jean-Pierre; Marti-Batlle, Daniele; Fagret, Daniel; Fontaine, Eric; Pasqualini, Roberto

    2006-01-01

    A major goal of nuclear oncology is the development of new radiolabelled tracers as proliferation markers. Intracellular calcium waves play a fundamental role in the course of the cell cycle. These waves occur in non-excitable tumour cells via store-operated calcium channels (SOCCs). Bis(N-ethoxy, N-ethyldithiocarbamato) nitrido technetium (V)-99m ( 99m TcN-NOET) has been shown to interact with L-type voltage-operated calcium channels (VOCCs) in cultured cardiomyocytes. Considering the analogy between VOCCs and SOCCs, we sought to determine whether 99m TcN-NOET also binds to activated SOCCs in tumour cells in order to clarify the potential value of this tracer as a proliferation marker. Uptake kinetics of 99m TcN-NOET were measured in human leukaemic HL-60 cells over 60 min and the effect of several calcium channel modulators on 1-min tracer uptake was studied. The uptake kinetics of 99m TcN-NOET were compared both with the variations of cytosolic free calcium concentration measured by indo-1/AM and with the variations in the SG 2 M cellular proliferation index. All calcium channel inhibitors significantly decreased the cellular uptake of 99m TcN-NOET whereas the activator thapsigargin induced a significant 10% increase. In parallel, SOCC activation by thapsigargin, as measured using the indo-1/AM probe, was inhibited by nicardipine. These results indicate that the uptake of 99m TcN-NOET is related to the activation of SOCCs. Finally, a correlation was observed between the tracer uptake and variations in the proliferation index SG 2 M. The uptake of 99m TcN-NOET seems to be related to SOCC activation and to cell proliferation in HL-60 cells. These results indicate that 99m TcN-NOET might be a marker of cell proliferation. (orig.)

  7. Calcium transport in sealed vesicles from red beet (Beta vulgaris L.) storage tissue. II. Characterization of 45Ca2+ uptake into plasma membrane vesicles

    International Nuclear Information System (INIS)

    Giannini, J.L.; Ruiz-Cristin, J.; Briskin, D.P.

    1987-01-01

    Calcium uptake was examined in sealed plasma membrane vesicles isolated from red beet (Beta vulgaris L.) storage tissue using 45 Ca 2+ . Uptake of 45 Ca 2+ by the vesicles was ATP-dependent and radiotracer accumulated by the vesicles could be released by the addition of the calcium ionophore A23187. The uptake was stimulated by gramicidin D but slightly inhibited by carbonylcyanide m-chlorophenylhydrazone. Although the latter result might suggest some degree of indirect coupling of 45 Ca 2+ uptake to ATP utilization via ΔμH + , no evidence for a secondary H + /Ca 2+ antiport in this vesicle system could be found. Following the imposition of an acid-interior pH gradient, proton efflux from the vesicle was not enhanced by the addition of Ca 2+ and an imposed pH gradient could not drive 45 Ca 2+ uptake. Optimal uptake of 45 Ca 2+ occurred broadly between pH 7.0 and 7.5 and the transport was inhibited by orthovanadate, N,N'-dicyclohexylcarbodiimide, and diethylstilbestrol but insensitive to nitrate and azide. The dependence of 45 Ca 2+ uptake on both calcium and Mg:ATP concentration demonstrated saturation kinetics with K/sub m/ values of 6 micromolar and 0.37 millimolar, respectively. While ATP was the preferred substrate for driving 45 Ca 2+ uptake, GTP could drive transport at about 50% of the level observed for ATP. The results of this study demonstrate the presence of a unique primary calcium transport system associated with the plasma membrane which could drive calcium efflux from the plant cell

  8. The effect of growth regulators on the uptake and distribution of calcium in Golden Delicious apples

    International Nuclear Information System (INIS)

    Steenkamp, J.; De Villiers, O.T.

    1979-01-01

    45 Ca, applied to the roots of Golden Delicious apple seedlings, was readily absorbed and transported to the leaves. Application of NAAm to the leaves of seedlings significantly increased the uptake of 45 Ca, whereas the growth regulators GA 3 , kinetin, SADH, CEPA and 2,4,5-TP had no such effect. Application of NAAm to intact fruits and fruit discs also significantly increased the uptake of 45 Ca [af

  9. Changes in calcium uptake rate by rat cardiac mitochondria during postnatal development.

    Science.gov (United States)

    Bassani, R A; Fagian, M M; Bassani, J W; Vercesi, A E

    1998-10-01

    Ca2+ uptake, transmembrane electrical potential (Deltapsim) and oxygen consumption were measured in isolated ventricular mitochondria of rats from 3 days to 5 months of age. Estimated values of ruthenium red-sensitive, succinate-supported maximal rate of Ca2+ uptake (Vmax, expressed as nmol Ca2+/min/mg protein) were higher in neonates and gradually fell during postnatal development (from 435+/-24 at 3-6 days, to 156+/-10 in adults,Palpha-ketoglutarate as substrates) and state 3ADP (alpha-ketoglutarate-supported) respiration rates, as well as Deltapsim values (approximately-150 mV). Respiration-independent Deltapsim and Ca2+ uptake, supported by valinomycin-induced K+ efflux were also investigated at these ages. A transient Deltapsim (approximately -30 mV) was evoked by valinomycin in both neonatal and adult mitochondria. Respiration-independent Ca2+ uptake was also transient, but its initial rate was significantly higher in neonates than in adults (49. 4+/-10.0v 28.0+/-5.7 mmol Ca2+/min/mg protein,P<0.01). These results indicate that Ca2+ uptake capacity of rat cardiac mitochondria is remarkably high just after birth and declines over the first weeks of postnatal life, without change in apparent affinity of the transporter. Increased mitochondrial Ca2+ uptake rate in neonates appears to be related to the uniporter itself, rather than to modification of the driving force of the transport. Copyright 1998 Academic Press

  10. Uptake of CrO42- ions by Fe-treated tri-calcium phosphate

    International Nuclear Information System (INIS)

    Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E.

    2010-01-01

    CrO 4 2- ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10 -4 M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO 4 2- ions was 7.10 x 10 -3 mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters ΔH 0 , ΔG 0 and ΔS 0 were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

  11. Role of mitochondrial calcium uptake homeostasis in resting state fMRI brain networks.

    Science.gov (United States)

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

    2015-11-01

    Mitochondrial Ca(2+) uptake influences both brain energy metabolism and neural signaling. Given that brain mitochondrial organelles are distributed in relation to vascular density, which varies considerably across brain regions, we hypothesized different physiological impacts of mitochondrial Ca(2+) uptake across brain regions. We tested the hypothesis by monitoring brain "intrinsic activity" derived from the resting state functional MRI (fMRI) blood oxygen level dependent (BOLD) fluctuations in different functional networks spanning the somatosensory cortex, caudate putamen, hippocampus and thalamus, in normal and perturbed mitochondrial Ca(2+) uptake states. In anesthetized rats at 11.7 T, mitochondrial Ca(2+) uptake was inhibited or enhanced respectively by treatments with Ru360 or kaempferol. Surprisingly, mitochondrial Ca(2+) uptake inhibition by Ru360 and enhancement by kaempferol led to similar dose-dependent decreases in brain-wide intrinsic activities in both the frequency domain (spectral amplitude) and temporal domain (resting state functional connectivity; RSFC). The fact that there were similar dose-dependent decreases in the frequency and temporal domains of the resting state fMRI-BOLD fluctuations during mitochondrial Ca(2+) uptake inhibition or enhancement indicated that mitochondrial Ca(2+) uptake and its homeostasis may strongly influence the brain's functional organization at rest. Interestingly, the resting state fMRI-derived intrinsic activities in the caudate putamen and thalamic regions saturated much faster with increasing dosage of either drug treatment than the drug-induced trends observed in cortical and hippocampal regions. Regional differences in how the spectral amplitude and RSFC changed with treatment indicate distinct mitochondrion-mediated spontaneous neuronal activity coupling within the various RSFC networks determined by resting state fMRI. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Effects of NAA on the uptake and accumulation of calcium in chinese cabbage

    International Nuclear Information System (INIS)

    Miao Ying; Cao Jiashu; Jiang Youtiao; Zeng Guangwen

    1998-01-01

    The involvement of plant growth regulator in polar transport of Ca 2+ in Chinese cabbage was studied using hydroponics system with 45 Ca radioisotope. Treatment of NAA either by foliage spray or root-feeding increased the uptake of 45 Ca by root, raising the 45 Ca accumulation in stems, which was remarkably higher than that of control, especially in root-fed plants. NAA treatment also increased the folio uptake of applied 45 Ca and thus the accumulation of 45 Ca in the leaves. This was more significant when NAA was applied to inner leaves. The same results was obtained in the experiment of 45 Ca radioautography with the whole plants

  13. Localised uptake and extraction of Calcium/sup 45/ in dinoflagellate nuclei: An autoradiographic study

    Energy Technology Data Exchange (ETDEWEB)

    Sigee, D.C.

    1983-01-01

    The uptake of Ca/sup 45/ into cells of the dinoflagellate Glenodinium foliaceum was investigated using insoluble compound light microscope autoradiography. The distribution of silver grains showed marked localisation to the dinocaryotic nucleus, with a random scatter of grains over the surrounding protoplasm (cytoplasm and supernumerary nucleus). Correction of grain counts for lateral sensitisation from the dinocaryotic nucleus indicated an isotope concentration 16-32 times greater in this organelle compared to the rest of the cell. Cells labelled for varying periods of time showed differences in the pattern of Ca/sup 45/ uptake throughout the sample populations, but no increase in the mean level of uptake per cell. This would suggest a rapid incorporation of isotope within 1-2 hours, with little subsequent uptake. The presence of high levels of label after processing with both additive (glutaraldehyde, paraformaldehyde) and coagulative (acetic alcohol) fixatives indicated that the retention of Ca/sup 45/ in these preparations was not simply a fixation artefact. Although the isotope did not appear to be suitable for (high resolution) electron microscope autoradiography, the intranuclear site of incorporation was demonstrated indirectly using a buffer extraction technique. Prolonged treatment with phosphate buffer resulted in a large scale loss of label from both cytoplasm and dinocaryotic nucleus. The latter appeared to show specific correlation with the loss of (protein) matrix from the chromosomes - as observed under both light and electron microscopy, with no apparent change in either nucleolus or nucleoplasm. This would suggest that incorporated Ca/sup 45/ in the nucleus was largely confined to the condensed chromatin, where it was combined with the acidic proteins which make up the bulk of the chromatin matrix. The results obtained in this investigation are related to previous studies involving X-ray microanalysis and uptake of Ni/sup 63/.

  14. Probing the limit of magnesium uptake by β-tricalcium phosphate in biphasic mixtures formed from calcium deficient apatites

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P. Nandha; Mishra, Sandeep K.; Kannan, S., E-mail: para_kanna@yahoo.com

    2015-11-15

    A series of magnesium doped non-stoichiometric calcium deficient apatites were synthesized through an aqueous precipitation route. The resultant structural changes during heat treatment were investigated by X-ray diffraction, Raman and FT-IR spectroscopy and Rietveld refinement. The results confirmed the formation of biphasic mixtures comprising Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} and β-Ca{sub 3}(PO{sub 4}){sub 2} after heat treatment at 1000 °C with the preferential occupancy of Mg{sup 2+} at the crystal lattice of β-Ca{sub 3}(PO{sub 4}){sub 2}. The concentration of Mg{sup 2+} uptake in β-Ca{sub 3}(PO{sub 4}){sub 2} is limited till reaching the stoichiometric ratio of (Ca+Mg)/P=1.67 and beyond this stoichiometric value [(Ca+Mg)/P>1.67], Mg{sup 2+} precipitates as Mg(OH){sub 2} and thereafter gets converted to MgO during heat treatment. Any kind of Mg{sup 2+} uptake in the crystal lattice of Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2} is discarded from the investigation. - Highlights: • Aqueous co-precipitation of calcium deficient apatites with excess magnesium (Mg{sup 2+}) additions. • Heat treatments beyond 800 °C results in the formation of biphasic apatite mixtures. • Mg{sup 2+} gets accommodated at the β-Ca{sub 3}(PO{sub 4}){sub 2} lattice of biphasic mixtures. • Mg{sup 2+} additions exceeding stoichiometric value (Ca/P>1.67) results in its formation as MgO. • Mg{sup 2+} occupancy at β-Ca{sub 3}(PO{sub 4}){sub 2} lattice delays its allotropic conversion α-Ca{sub 3}(PO{sub 4}){sub 2} till 1350 °C.

  15. Measurement of intestinal calcium uptake in pigs with vitamin-D-dependent rickets

    International Nuclear Information System (INIS)

    Harmeyer, J.; Vogelsang, G.; Grabe, C. von

    1976-01-01

    Pigs that suffer from an inherited from of vitamin-D-refractory rickets were treated with two hydroxylated derivatives of vitamin-D, 25(OH)D 3 and l,25(OH) 2 D 3 . Doses of 10 μg of 25-hydroxy vitamin-D 3 were intravenously administered over a ten days' period. The treatment was not capable of correcting hypocalcaemia and hypophosphataemia within 12 days. Clinical and biochemical lesions of rickets improved, however, within three days after a single intravenous injection of 7.5 mg of vitamin-D 3 . Long term administration of physiologic doses of 1,25(OH) 2 D 3 improved haematological and intestinal defects of vitamin-D deficiency. Fractional losses of radiocalcium from plasma and the fraction of radiocalcium absorbed increased considerably after the treatment. It was concluded from the specific response to treatment with 1,25(OH) 2 D 3 and from the refractoriness to physiologic doses of vitamin-D and to 25(OH)D 3 that the pigs suffer from pseudo-vitamin-D- deficiency rickets. The animals may serve as a suitable model for further studies on the potential factors regulating calcium homeostasis and vitamin-D metabolism. (author)

  16. Evidence for a dihydropyridine-sensitive and conotoxin-insensitive release of noradrenaline and uptake of calcium in adrenal chromaffin cells.

    Science.gov (United States)

    Owen, P. J.; Marriott, D. B.; Boarder, M. R.

    1989-01-01

    1. It has been suggested that neuronal voltage-sensitive calcium channels (VSCC) may be divided into dihydropyridine (DHP)-sensitive (L) and DHP-insensitive (N and T), and that both the L and the N type channels are attenuated by the peptide blocker omega-conotoxin. Here the effects of omega-conotoxin on release of noradrenaline and uptake of calcium in bovine adrenal chromaffin cells were investigated. 2. Release of noradrenaline in response to 25 mM K+, 65 mM K+, 10 nM bradykinin or 10 microM prostaglandin E1 was not affected by omega-conotoxin in the range 10 nM-1 microM. 3. 45Ca2+ uptake stimulated by high K+ and prostaglandin was attenuated by 1 microM nitrendipine and enhanced by 1 microM Bay K 8644; these calcium fluxes were not modified by 20 nM omega-conotoxin. 4. With superfused rat brain striatal slices in the same medium as the above cell studies, release of dopamine in response to 25 mM K+ was attenuated by 20 nM omega-conotoxin. 5. These results show that in these neurone-like cells, release may be effected by calcium influx through DHP-sensitive but omega-conotoxin-insensitive VSCC, a result inconsistent with the suggestion that omega-conotoxin blocks both L-type and N-type neuronal calcium channels. PMID:2470457

  17. Association between cadmium and calcium uptake and distribution during the moult cycle of female shore crabs, Carcinus maenas: an in vivo study

    International Nuclear Information System (INIS)

    Bondgaard, Morten; Bjerregaard, Poul

    2005-01-01

    Net influxes into the haemolymph and tissue distribution of 45 Ca and 109 Cd were studied in vivo in female Carcinus maenas at different moult stages. Net influxes of 45 Ca and 109 Cd from water were higher in postmoult (A and B) C. maenas than in C 3 - and C 4 -intermoult crabs and the net influx of calcium was higher in C 3 -intermoult crabs than in C 4 -intermoult crabs. The net influxes of 45 Ca and 109 Cd increased in postmoult C. maenas with decreasing external calcium concentrations at constant salinity. At all external calcium concentrations a significant correlation existed between 45 Ca and 109 Cd accumulated in the haemolymph of individual animals. In vivo exposure of postmoult C. maenas to external lanthanum decreased the 45 Ca and 109 Cd uptake rates to 30 and 10%, respectively, of the control values. About 30% of injected 109 Cd were found in the midgut gland, 10-20% in the gills and only a few (1-2) percent was lost to the seawater 24 h after injection. No major variations in tissue distribution of 109 Cd were observed between moult stages in these tissues. Premoult crabs retained more cadmium in the haemolymph 24 h after injection than other moult stages, and postmoult crabs retained more in muscle. Between 20 and 40% of the injected 45 Ca were excreted to the water, while only a few percent of the injected 45 Ca were found in the soft tissues 24 h after injection. Large moult stage variations, however, were observed in the tissue distribution of internalised 45 Ca. This study demonstrates that cadmium and calcium uptakes are elevated in postmoult C. maenas. The results indicate that cadmium and calcium in this stage are taken up via Ca 2+ -channels located in the apical membrane of gill epithelium cells. When internalised, however, cadmium and calcium are metabolised in fundamentally different ways, determined by the chemical properties and biological significance of the two metals

  18. Reciprocal enhancement of uptake and toxicity of cadmium and calcium in rainbow trout (Oncorhynchus mykiss) liver mitochondria

    International Nuclear Information System (INIS)

    Adiele, Reginald C.; Stevens, Don; Kamunde, Collins

    2010-01-01

    The interactive effects of cadmium (Cd) and calcium (Ca) on energy metabolism in rainbow trout liver mitochondria were studied to test the prediction that Ca would protect against Cd-induced mitochondrial liability. Isolated rainbow trout liver mitochondria were energized with malate and glutamate and exposed to increasing concentrations (5-100 μM) of Cd and Ca singly and in combination at 15 o C. Accumulation of Cd and Ca in the mitochondria and mitochondrial respiration (oxygen consumption) rates were measured. Additionally, un-energized mitochondria were incubated with low doses (1 μM) of Cd and Ca singly and in combination, with time-course measurements of cation accumulation/binding and oxygen consumption rates. In energized actively phosphorylating mitochondria, the uptake rates of both Cd and Ca were dose-dependent and enhanced when administered concurrently. Upon low-dose incubation, Cd accumulation was rapid and peaked in 5 min, while no appreciable uptake of Ca occurred. Functionally, the resting (state 4, ADP-limited) respiration rate was not affected in the dose-response exposure, but it decreased remarkably on low-dose incubation. Adenosine diphosphate (ADP)-stimulated respiration (state 3) rate was impaired dose-dependently with maximal inhibitions (at the highest dose, 100 μM) of 32, 64 and 73% for Ca, Cd, and combined exposures, respectively. The combined effects of Ca and Cd suggested synergistic (more than additive) action and partial additivity of effects at low and higher doses of the two cations, respectively. Moreover, on a molar basis, Cd was twice as toxic as Ca to rainbow trout liver mitochondria and when combined, approximately 90% of the effects were attributable to Cd. The coupling efficiency, as measured by respiratory control ratio (RCR) and phosphorylation efficiency, measured as ADP/O ratio, both decreased as the exposure dosage and duration increased. In addition, Cd and Ca exposure decreased mitochondrial proton leak (state 4

  19. Saponarin activates AMPK in a calcium-dependent manner and suppresses gluconeogenesis and increases glucose uptake via phosphorylation of CRTC2 and HDAC5.

    Science.gov (United States)

    Seo, Woo-Duck; Lee, Ji Hae; Jia, Yaoyao; Wu, Chunyan; Lee, Sung-Joon

    2015-11-15

    This study investigated the molecular mechanism of saponarin, a flavone glucoside, in the regulation of insulin sensitivity. Saponarin suppressed the rate of gluconeogenesis and increased cellular glucose uptake in HepG2 and TE671 cells by regulating AMPK. Using an in vitro kinase assay, we showed that saponarin did not directly interact with the AMPK protein. Instead, saponarin increased intracellular calcium levels and induced AMPK phosphorylation, which was diminished by co-stimulation with STO-609, an inhibitor of CAMKKβ. Transcription of hepatic gluconeogenesis genes was upregulated by nuclear translocation of CRTC2 and HDAC5, coactivators of CREB and FoxO1 transcription factors, respectively. This nuclear translocation was inhibited by increased phosphorylation of CRTC2 and HDAC5 by saponarin-induced AMPK in HepG2 cells and suppression of CREB and FoxO1 transactivation activities in cells stimulated by saponarin. The results from a chromatin immunoprecipitation assay confirmed the reduced binding of CRTC2 on the PEPCK and G6Pase promoters. In TE671 cells, AMPK phosphorylated HDAC5, which suppressed nuclear penetration and upregulated GLUT4 transcription, leading to enhanced glucose uptake. Collectively, these results suggest that saponarin activates AMPK in a calcium-dependent manner, thus regulating gluconeogenesis and glucose uptake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Failure to demonstrate a major role for Kupffer cells and radiosensitive leukocytes in immunoglobulin-mediated elimination of Trypanosoma musculi

    International Nuclear Information System (INIS)

    Kongshavn, P.A.; Shaw, K.; Ghadirian, E.; Ulczak, O.

    1990-01-01

    Previous studies have indicated that elimination of parasitemia in Trypanosoma musculi infection is brought about by immunoglobulin G2a antibodies, C3, and an effector cell. Experiments were designed to identify the putative effector cell by using several approaches. Infected C5-deficient or C5-sufficient mice treated with silica particles or given 900 rads of radiation 3 days earlier effectively eliminated trypanosomes following administration of immune plasma (IP). Silica-treated, noninfected mice given T. musculi preincubated with IP also cleared the parasites. Radiolabeling studies revealed that uptake of the cleared trypanosomes by the liver in normal mice was relatively low and fell only slightly (19%) in silica-treated mice. In contrast, uptake of radiolabeled sheep erythrocytes by the liver was normally much higher and fell drastically (7%) in silica-treated mice. Mice were then immunocompromised by 900 rads of radiation, silica particles, and anti-platelet serum combined before IP-sensitized trypanosomes were given. Leukocyte and platelet counts were both reduced by 95% and sheep erythrocyte uptake by the liver fell from 77 to 5%; however, greater than 99% of the injected trypanosomes were cleared in these mice and uptake of radiolabeled trypanosomes by the liver was similar to that of normal mice. Lastly, in anesthetized mice in which Kupffer cells were excluded surgically from the circulation, greater than 99% of the IP-sensitized trypanosomes disappeared rapidly from the blood. Only 7% of the radiolabel was found in the liver versus 60% in sham-operated mice. The results are interpreted as showing that hepatic Kupffer cells play a minor role in the immune elimination of T. musculi. Likewise, radiosensitive leukocytes and platelets are unlikely to be sole candidates for the putative effector cell that mediates a cure of murine trypanosomiasis

  1. Low-intensity pulsed ultrasound (LIPUS) stimulates mineralization of MC3T3-E1 cells through calcium and phosphate uptake.

    Science.gov (United States)

    Tassinary, João Alberto Fioravante; Lunardelli, Adroaldo; Basso, Bruno de Souza; Dias, Henrique Bregolin; Catarina, Anderson Velasque; Stülp, Simone; Haute, Gabriela Viegas; Martha, Bianca Andrade; Melo, Denizar Alberto da Silva; Nunes, Fernanda Bordignon; Donadio, Márcio Vinícius Fagundes; Oliveira, Jarbas Rodrigues de

    2018-03-01

    The present study aimed to evaluate the effect of low-intensity pulsed ultrasound (LIPUS) on pre-osteoblast mineralization using in vitro bioassays. Pre-osteoblastic MC3T3-E1 cells were exposed to LIPUS at 1 MHz frequency, 0.2 W/cm 2 intensity and 20% duty cycle for 30 min. The analyses were carried out up to 336 h (14 days) after exposure. The concentration of collagen, phosphate, alkaline phosphatase, calcium and transforming growth factor beta 1 (TGF-β1) in cell supernatant and the presence of calcium deposits in the cells were analyzed. Our results showed that LIPUS promotes mineralized nodules formation. Collagen, phosphate, and calcium levels were decreased in cell supernatant at 192 h after LIPUS exposure. However, alkaline phosphatase and TGF-β1 concentrations remained unchanged. Therapeutic pulsed ultrasound is capable of stimulating differentiation and mineralization of pre-osteoblastic MC3T3-E1 cells by calcium and phosphate uptake with consequent hydroxyapatite formation. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Effects of dietary calcium and cadmium on cadmium accumulation, calcium and cadmium uptake from the water, and their interactions in juvenile rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Baldisserotto, B. [Departamento de Fisiologia, Universidade Federal de Santa Maria, 97105.900 Santa Maria, RS (Brazil); Chowdhury, M.J. [Department of Biology, McMaster University, Hamilton, Ont., L8S 4K1 (Canada); Wood, Chris M. [Department of Biology, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: woodcm@mcmaster.ca

    2005-03-25

    The objective of this study was to examine the effects of chronically elevated dietary Ca{sup 2+} (as CaCO{sub 3}), alone and in combination with elevated dietary Cd, on survival, growth, and Cd and Ca{sup 2+} accumulation in several internal compartments in juvenile rainbow trout (Oncorhynchus mykiss). In addition, effects on short-term branchial uptake and internal distribution of newly accumulated waterborne Ca{sup 2+} and Cd during acute waterborne Cd exposure (50 {mu}g/L as CdNO{sub 3} for 3 h) were monitored using radiotracers ({sup 45}Ca, {sup 65}Cd). Fish were fed with four diets: 20 mg Ca{sup 2+}/g food (control), 50 mg Ca{sup 2+}/g food, 300 {mu}g Cd/g food, and 50 mg Ca{sup 2+}/g + 300 {mu}g Cd/g food for 30 days. There were no significant effects on growth, mortality, or total body Ca{sup 2+} accumulation. The presence of elevated Ca{sup 2+}, Cd, or Ca{sup 2+} + Cd in the diet all reduced waterborne Ca{sup 2+} uptake in a short-term experiment (3 h), though the inhibitory mechanisms appeared to differ. The effects were marked after 15 days of feeding, but attenuated by 30 days, except when the diet was elevated in both Ca{sup 2+} and Cd. The presence of elevated Ca{sup 2+} in the diet had only modest influence on Cd uptake from the water during acute Cd challenges but greatly depressed Cd uptake from the diet and accumulation in most internal tissues. None of the treatment diets prevented the decreases in waterborne Ca{sup 2+} uptake and new Ca{sup 2+} accumulation in internal tissues caused by acute exposure to waterborne Cd. In conclusion, there are complex interactions between waterborne and dietary effects of Ca{sup 2+} and Cd. Elevated dietary Ca{sup 2+} protects against both dietary and waterborne Cd uptake, whereas both waterborne and dietary Cd elevations cause reduced waterborne Ca{sup 2+} uptake.

  3. Uptake of CrO{sub 4}{sup 2-} ions by Fe-treated tri-calcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Serrano G, J.; Ramirez S, J. L.; Bonifacio M, J.; Granados C, F.; Badillo A, V. E., E-mail: juan.serrano@inin.gob.m [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    CrO{sub 4}{sup 2-} ion adsorption of Fe-treated tri-calcium phosphate was studied by batch experiments as a function of contact time, initial concentration of metal ion and temperature. Adsorption results showed that at ph 5.5 and 1.0 x 10{sup -4} M chromium concentration the adsorption capacity of Fe-treated tri-calcium phosphate for CrO{sub 4}{sup 2-} ions was 7.10 x 10{sup -3} mmol/g. Chromium adsorption data on Fe-treated tri-calcium phosphate at various initial concentration fitted the Freundlich isotherm. By temperature studies the thermodynamic parameters {Delta}H{sup 0}, {Delta}G{sup 0} and {Delta}S{sup 0} were estimated and the obtained results showed that the adsorption reaction was endothermic and spontaneous. (Author)

  4. Reduced myocardial 18F-FDG uptake after calcium channel blocker administration. Initial observation for a potential new method to improve plaque detection

    International Nuclear Information System (INIS)

    Gaeta, Chiara; Flotats, Albert; Artigas, Carles; Deportos, Jordi; Geraldo, Llanos; Carrio, Ignasi; Fernandez, Yolanda; Pavia, Javier

    2011-01-01

    Physiological glucose uptake by the myocardium may hamper visualization of coronary atherosclerotic plaques in 18 F-FDG PET studies. Intracellular myocardial calcium relates to glucose influx. We assessed whether administration of a calcium channel blocker such as verapamil could decrease myocardial 18 F-FDG uptake in mice. Experiments were conducted on ten male C57BL/6JOlaHsd mice. The mice were studied by 18 F-FDG PET/CT under basal conditions and after a single administration of verapamil injected 1 h prior to 18 F-FDG administration at doses of 1 mg/kg (group A, n = 5) and 20 mg/kg (group B, n = 5). PET scanning was started 60 min after injection of 18 F-FDG employing a dedicated small-animal PET/CT system (ARGUS-CT). In each mouse, post-verapamil PET images were coregistered with the basal PET images. Volumetric regions of interest (VOI) were drawn on the basal study containing the myocardium of the whole left ventricle and quantitatively compared with the same VOI applied to the post-verapamil scan. The SUV mean was used to express the mean myocardial 18 F-FDG uptake. The relative coefficient of variation (RV) between the basal and post-verapamil conditions was calculated. Verapamil administration decreased myocardial 18 F-FDG uptake in all animals. The median (range) SUV mean values in group A were 2.6 (1.6-4.1) under basal conditions and 1.7 (1.1-2.9) after verapamil administration (p = 0.043), and in group B were 1.6 (1.3-2.0) under basal conditions and 1.0 (0.9-1.4) after verapamil administration (p = 0.043). The median (range) RV values were -31% (-5%, -50%) in group A, and -37% (-10%, -51%) in group B (p = 0.6). In this animal model there was a significant reduction in 18 F-FDG uptake in the myocardium following verapamil administration. This type of intervention could facilitate the definition of coronary atherosclerotic plaque inflammation on 18 F-FDG PET scans. (orig.)

  5. In vivo effect of 3,5,3'-triiodothyronine on calcium uptake in several tissues in the rat: Evidence for a physiological role for calcium as the first messenger for the prompt action of thyroid hormone at the level of the plasma membrane

    International Nuclear Information System (INIS)

    Segal, J.

    1990-01-01

    Calcium has been shown in vitro to serve as the first messenger for the rapid effect of thyroid hormone at the level of the plasma membrane. In the present study the physiological relevance of this mechanism is examined in the whole animal. To this end, the effect of T3 on 45calcium uptake and sugar 2-deoxyglucose (2-DG) uptake, an effect that requires extracellular calcium, and the influence of calcium blockers thereon were measured in ventricles, atria, diaphragm, fat, and liver in the rat. In the first three tissues, T3 produced comparable changes in 45Ca uptake and 2-DG uptake (T3 increased 2-DG uptake in fat, where 45Ca uptake was undetected, and had no effect in liver); this activity was blocked by the calcium channel blocker cadmium. The effect of T3 on 45Ca uptake, like its effect on the in vivo uptake of 2-DG described previously, was biphasic and time related; at physiological doses of 0.01 and 0.1 micrograms/100 g BW, T3 increased 45Ca uptake, whereas at greater (pharmacological) doses of 1 and 100 micrograms/100 g BW, T3 was without effect or inhibited 45Ca uptake. In ventricles and atria, the stimulatory effect of T3 on 45Ca uptake was very rapid within 2 min, at which time it was at or near maximum (50-90% above control) and then declined gradually and was not seen after 10-20 min. Of the several calcium blockers employed, verapamil (organic) and cadmium (inorganic) were found to be the most effective. Verapamil and cadmium produced a rapid, transient, and dose-related inhibition of 45Ca uptake in the tissues examined (except fat tissue where, under the experimental conditions employed, 45Ca uptake was undetected). Verapamil, given iv (200 micrograms/100 g BW) or ip (1 mg/100 g BW), reduced tissue 45Ca uptake by 50-90% within 2 or 10 min, respectively, and then its inhibitory effect diminished rapidly and was not seen after 20-30 min

  6. Actinide immobilization in the subsurface environment by in-situ treatment with a hydrolytically unstable organophosphorus complexant: Uranyl uptake by calcium phytate

    International Nuclear Information System (INIS)

    Nash, K.L.; Jensen, M.P.; Schmidt, M.A.

    1997-01-01

    In addition to naturally occurring uranium and thorium, actinide ions exist in the subsurface environment as a result of accidental releases and intentional disposal practices associated with nuclear weapons production. These species present a significant challenge to cost-effective remediation of contaminated environments. An attractive approach to decreasing the probability of actinide migration in the subsurface is to transform the ions into a less mobile form by remote treatment. We have under development a process which relies on a polyfunctional organophosphorus complexant to sequester the mobile metal ions by complexation/cation exchange in the near term, and to subsequently decompose, transforming the actinides into insoluble phosphate mineral forms in the long term. Studies to date include identification of a suitable organophosphorus reagent, profiling of its decomposition kinetics, verification of the formation of phosphate mineral phases upon decomposition of the reagent, and extensive comparison of the actinide uptake ability of the calcium salt of the reagent as compared with hydroxyapatite. In this report, we briefly describe the process with focus on the cation exchange behavior of the calcium salt of the organophosphorus sequestrant

  7. Synthetic peptides corresponding to human follicle-stimulating hormone (hFSH)-beta-(1-15) and hFSH-beta-(51-65) induce uptake of 45Ca++ by liposomes: evidence for calcium-conducting transmembrane channel formation

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, P.; Santa-Coloma, T.A.; Reichert, L.E. Jr. (Department of Biochemistry, Albany Medical College, New York, NY (USA))

    1991-06-01

    We have previously described FSH receptor-mediated influx of 45Ca++ in cultured Sertoli cells from immature rats and receptor-enriched proteoliposomes via activation of voltage-sensitive and voltage-independent calcium channels. We have further shown that this effect of FSH does not require cholera toxin- or pertussis toxin-sensitive guanine nucleotide binding protein or activation of adenylate cyclase. In the present study, we have identified regions of human FSH-beta-subunit which appear to be involved in mediating calcium influx. We screened 11 overlapping peptide amides representing the entire primary structure of hFSH-beta-subunit for their effects on 45Ca++ flux in FSH receptor-enriched proteoliposomes. hFSH-beta-(1-15) and hFSH-beta-(51-65) induced uptake of 45Ca++ in a concentration-related manner. This effect of hFSH-beta-(1-15) and hFSH-beta-(51-65) was also observed in liposomes lacking incorporated FSH receptor. Reducing membrane fluidity by incubating liposomes (containing no receptor) with hFSH-beta-(1-15) or hFSH-beta-(51-65) at temperatures lower than the transition temperatures of their constituent phospholipids resulted in no significant (P greater than 0.05) difference in 45Ca++ uptake. The effectiveness of the calcium ionophore A23187, however, was abolished. Ruthenium red, a voltage-independent calcium channel antagonist, was able to completely block uptake of 45Ca++ induced by hFSH-beta-(1-15) and hFSH-beta-(51-65) whereas nifedipine, a calcium channel blocker specific for L-type voltage-sensitive calcium channels, was without effect. These results suggest that in addition to its effect on voltage-sensitive calcium channel activity, interaction of FSH with its receptor may induce formation of transmembrane aqueous channels which also facilitate influx of extracellular calcium.

  8. The rapid mode of calcium uptake into heart mitochondria (RaM): comparison to RaM in liver mitochondria.

    Science.gov (United States)

    Buntinas, L; Gunter, K K; Sparagna, G C; Gunter, T E

    2001-04-02

    A mechanism of Ca(2+) uptake, capable of sequestering significant amounts of Ca(2+) from cytosolic Ca(2+) pulses, has previously been identified in liver mitochondria. This mechanism, the Rapid Mode of Ca(2+) uptake (RaM), was shown to sequester Ca(2+) very rapidly at the beginning of each pulse in a sequence [Sparagna et al. (1995) J. Biol. Chem. 270, 27510-27515]. The existence and properties of RaM in heart mitochondria, however, are unknown and are the basis for this study. We show that RaM functions in heart mitochondria with some of the characteristics of RaM in liver, but its activation and inhibition are quite different. It is feasible that these differences represent different physiological adaptations in these two tissues. In both tissues, RaM is highly conductive at the beginning of a Ca(2+) pulse, but is inhibited by the rising [Ca(2+)] of the pulse itself. In heart mitochondria, the time required at low [Ca(2+)] to reestablish high Ca(2+) conductivity via RaM i.e. the 'resetting time' of RaM is much longer than in liver. RaM in liver mitochondria is strongly activated by spermine, activated by ATP or GTP and unaffected by ADP and AMP. In heart, RaM is activated much less strongly by spermine and unaffected by ATP or GTP. RaM in heart is strongly inhibited by AMP and has a biphasic response to ADP; it is activated at low concentrations and inhibited at high concentrations. Finally, an hypothesis consistent with the data and characteristics of liver and heart is presented to explain how RaM may function to control the rate of oxidative phosphorylation in each tissue. Under this hypothesis, RaM functions to create a brief, high free Ca(2+) concentration inside mitochondria which may activate intramitochondrial metabolic reactions with relatively small amounts of Ca(2+) uptake. This hypothesis is consistent with the view that intramitochondrial [Ca(2+)] may be used to control the rate of ADP phosphorylation in such a way as to minimize the probability of

  9. Release of cadmium from clays and plant uptake of cadium from soil as affected by potassium and calcium amendments

    International Nuclear Information System (INIS)

    Haghiri, F.

    1976-01-01

    The effects of percent K and/or Ca saturations on the release of Cd from Cd-treated H-clays (kaolinite and illite) and on the Cd availability to plants from Cd-treated Canfield silt loam soil were determined. The concentration of Cd in the dialyzates from both kaolinite and illite clays increased as the percent of Ca or K saturation of the clays in the suspension decreased. The release of Cd from both clays was greater in the presence of Ca than K. In a separate experiment, the concentration of Cd in soybean shoots (Glycine max L. Merr.) ''Corsoy'' decreased with increasing percent Ca or K saturation of the soil. The results indicated that Cd uptake by soybeam shoots could be impaired to a great extent by K application

  10. Increase vs. decrease of calcium uptake by isolated heart cells induced by H2O2 vs. HOCl

    International Nuclear Information System (INIS)

    Kaminishi, T.; Matsuoka, T.; Yanagishita, T.; Kako, K.J.

    1989-01-01

    Adult rat heart myocytes were labeled rapidly with exogenous [45Ca2+]. Addition of 2.5 mM H2O2 to the heart cell suspension raised the content of rapidly exchangeable intracellular Ca2+ twofold, whereas addition of 1-30 mM HOCl decreased the Ca2+ content. The H2O2-induced increase in Ca2+ content was dependent on the medium Na+, pH, and temperature but was not significantly affected by addition of verapamil, diltiazem, amiloride, or 3-aminobenzamide. The [3H]ouabain binding to myocytes was suppressed by H2O2, whereas the Ca2+ efflux from myocytes was not influenced. An uncoupler, carbonyl cyanide m-chlorophenylhydrazone, reduced Ca2+ content, implying that the H2O2-induced change in Ca2+ content was not directly related to ATP depletion. On the other hand, the H2O2-induced Ca2+ accumulation in myocytes was prevented by deferoxamine or o-phenanthroline. These results suggest that H2O2 inhibited Na+-K+-ATPase, resulting in an increase in intracellular Na+ concentration and stimulation of sarcolemmal Na+-Ca2+ exchange activity, which caused a transient net Ca2+ influx into myocytes. By contrast, HOCl decreased the Ca2+ content of the rapidly exchangeable pool below control levels and this action of HOCl was antagonized by 1,4-dithiothreitol. HOCl accelerated Ca2+ efflux from myocytes. Ca2+ uptake and Ca2+-ATPase of the isolated sarcoplasmic reticular (SR) fraction were highly sensitive to the action of HOCl. Ca2+ uptake by intracellular sites, studied with myocytes permeabilized with digitonin, was inhibited by both H2O2 and HOCl. Thus these results suggest that HOCl inhibits the SR Ca2+ pump, resulting in the observed acceleration of Ca2+ efflux from and decline in Ca2+ content of myocytes

  11. Bile acids induce necrosis in pancreatic stellate cells dependent on calcium entry and sodium‐driven bile uptake

    Science.gov (United States)

    Jakubowska, Monika A.; Gerasimenko, Julia V.; Gerasimenko, Oleg V.; Petersen, Ole H.

    2016-01-01

    Key points Acute biliary pancreatitis is a sudden and severe condition initiated by bile reflux into the pancreas.Bile acids are known to induce Ca2+ signals and necrosis in isolated pancreatic acinar cells but the effects of bile acids on stellate cells are unexplored.Here we show that cholate and taurocholate elicit more dramatic Ca2+ signals and necrosis in stellate cells compared to the adjacent acinar cells in pancreatic lobules; whereas taurolithocholic acid 3‐sulfate primarily affects acinar cells.Ca2+ signals and necrosis are strongly dependent on extracellular Ca2+ as well as Na+; and Na+‐dependent transport plays an important role in the overall bile acid uptake in pancreatic stellate cells.Bile acid‐mediated pancreatic damage can be further escalated by bradykinin‐induced signals in stellate cells and thus killing of stellate cells by bile acids might have important implications in acute biliary pancreatitis. Abstract Acute biliary pancreatitis, caused by bile reflux into the pancreas, is a serious condition characterised by premature activation of digestive enzymes within acinar cells, followed by necrosis and inflammation. Bile acids are known to induce pathological Ca2+ signals and necrosis in acinar cells. However, bile acid‐elicited signalling events in stellate cells remain unexplored. This is the first study to demonstrate the pathophysiological effects of bile acids on stellate cells in two experimental models: ex vivo (mouse pancreatic lobules) and in vitro (human cells). Sodium cholate and taurocholate induced cytosolic Ca2+ elevations in stellate cells, larger than those elicited simultaneously in the neighbouring acinar cells. In contrast, taurolithocholic acid 3‐sulfate (TLC‐S), known to induce Ca2+ oscillations in acinar cells, had only minor effects on stellate cells in lobules. The dependence of the Ca2+ signals on extracellular Na+ and the presence of sodium–taurocholate cotransporting polypeptide (NTCP) indicate a Na

  12. Follicle-stimulating hormone receptor-mediated uptake of 45Ca2+ by proteoliposomes and cultured rat sertoli cells: Evidence for involvement of voltage-activated and voltage-independent calcium channels

    International Nuclear Information System (INIS)

    Grasso, P.; Reichert, L.E. Jr.

    1989-01-01

    We have previously reported incorporation into liposomes of Triton X-100-solubilized FSH receptor-G-protein complexes derived from purified bovine calf testis membranes. In the present study we have used this model system to show that FSH induces flux of 45Ca2+ into such proteoliposomes in a hormone-specific concentration-dependent manner. FSH, inactivated by boiling, had no stimulatory effect on 45Ca2+ flux, nor did isolated alpha- or beta-subunits of FSH. Addition of GTP (or its analogs 5'-guanylylimidodiphosphate and guanosine-5'-O-[3-thiotriphosphate]) or sodium fluoride (in the presence or absence of GTP or its analogs) failed to induce 45Ca2+ flux into proteoliposomes, suggesting that the uptake of 45Ca2+ was receptor, and not G-protein, related. Voltage-independent (ruthenium red and gadolinium chloride) and voltage-activated (methyoxyverapamil and nifedipine) calcium channel-blocking agents reduced FSH-stimulated 45Ca2+ flux into proteoliposomes to control levels. FSH also induced uptake of 45Ca2+ by cultured rat Sertoli cells. Ruthenium red and gadolinium chloride had no effect on basal levels of 45Ca2+ uptake or estradiol secretion by cultured rat Sertoli cells, nor did methoxyverapamil or nifedipine. All four calcium channel blockers, however, were able to reduce FSH-induced 45Ca2+ uptake to basal levels and FSH-stimulated conversion of androstenedione to estradiol by up to 50%, indicating an involvement of Ca2+ in FSH-stimulated steroidogenesis. Our results suggest that the well documented changes in intracellular calcium levels consequent to FSH binding may be due, at least in part, to an influx of calcium through FSH receptor-regulated calcium channels

  13. Calcium-dependent protein kinase CPK31 interacts with arsenic transporter AtNIP1;1 and regulates arsenite uptake in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ruijie Ji

    Full Text Available Although arsenite [As(III] is non-essential and toxic for plants, it is effectively absorbed through various transporters into the roots. Here we identified a calcium-dependent protein kinase (CPK31 response for As(III tolerance in Arabidopsis. We identified CPK31 as an interacting protein of a nodulin 26-like intrinsic protein (NIP1;1, an aquaporin involved in As(III uptake. Similarly to the nip1;1 mutants, the loss-of-function mutants of CPK31 improved the tolerance against As(III but not As(V, and accumulated less As(III in roots than that of the wild-type plants. The promoter-β-glucuronidase and quantitative Real-Time PCR analysis revealed that CPK31 displayed overlapping expression profiles with NIP1;1 in the roots, suggesting that they might function together in roots. Indeed, the cpk31 nip1;1 double mutants exhibited stronger As(III tolerance than cpk31 mutants, but similar to nip1;1 mutants, supporting the idea that CPK31 might serve as an upstream regulator of NIP1;1. Furthermore, transient CPK31 overexpression induced by dexamethasone caused the decrease in As(III tolerance of transgenic Arabidopsis lines. These findings reveal that CPK31 is a key factor in As(III response in plants.

  14. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    NARCIS (Netherlands)

    Backx, P. H.; de Tombe, P. P.; van Deen, J. H.; Mulder, B. J.; ter Keurs, H. E.

    1989-01-01

    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium

  15. In vitro characterization of cadmium and zinc uptake via the gastro-intestinal tract of the rainbow trout (Oncorhynchus mykiss): Interactive effects and the influence of calcium

    International Nuclear Information System (INIS)

    Ojo, Adeola A.; Wood, Chris M.

    2008-01-01

    An in vitro gut sac technique was employed to study whether Cd and Zn uptake mechanisms in the gastro-intestinal tract of the rainbow trout are similar to those at the gills, where both metals are taken up via the Ca transport pathway. Metal accumulation in surface mucus, in the mucosal epithelium, and transport into the blood space were assayed using radiolabelled Cd or Zn concentrations of 50 μmol L -1 in the luminal (internal) saline. Elevated luminal Ca (10 or 100 mmol L -1 versus 1 mmol L -1 ) reduced Cd uptake into all three phases by approximately 60% in the stomach, but had no effect in the anterior, mid, or posterior intestine. This finding is in accordance with recent in vivo evidence that Ca is taken up mainly via the stomach, and that high [Ca] diets inhibit Cd accumulation from the food specifically in this section of the tract. In contrast, 10 mmol L -1 luminal Ca had no effect on Zn transport in any section, whereas 100 mmol L -1 Ca stimulated Zn uptake, by approximately threefold, into all three phases in the stomach only. There was no influence of elevated luminal Zn (10 mmol L -1 ) on Cd uptake in the stomach or anterior intestine, or of high Cd (10 mmol L -1 ) on Zn uptake in these sections. However, high [Zn] stimulated Cd transport into the blood space but inhibited accumulation in the mucosal epithelium and/or mucus-binding in the mid and posterior intestine, whereas high [Cd] exerted a reciprocal effect in the mid-intestine only. We conclude that Cd uptake occurs via an important Ca-sensitive mechanism in the stomach which is different from that at the gills, while Cd transport mechanisms in the intestine are not directly Ca-sensitive. Zn uptake does not appear to involve Ca uptake pathways, in contrast to the gills. These results are discussed in the context of other possible Cd and Zn transport pathways, and the emerging role of the stomach as an organ of divalent metal uptake

  16. In vitro characterization of cadmium and zinc uptake via the gastro-intestinal tract of the rainbow trout (Oncorhynchus mykiss): Interactive effects and the influence of calcium

    Energy Technology Data Exchange (ETDEWEB)

    Ojo, Adeola A. [Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1 (Canada)], E-mail: adeolaojo25@yahoo.com; Wood, Chris M. [Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1 (Canada)], E-mail: woodcm@mcmaster.ca

    2008-08-11

    An in vitro gut sac technique was employed to study whether Cd and Zn uptake mechanisms in the gastro-intestinal tract of the rainbow trout are similar to those at the gills, where both metals are taken up via the Ca transport pathway. Metal accumulation in surface mucus, in the mucosal epithelium, and transport into the blood space were assayed using radiolabelled Cd or Zn concentrations of 50 {mu}mol L{sup -1} in the luminal (internal) saline. Elevated luminal Ca (10 or 100 mmol L{sup -1}versus 1 mmol L{sup -1}) reduced Cd uptake into all three phases by approximately 60% in the stomach, but had no effect in the anterior, mid, or posterior intestine. This finding is in accordance with recent in vivo evidence that Ca is taken up mainly via the stomach, and that high [Ca] diets inhibit Cd accumulation from the food specifically in this section of the tract. In contrast, 10 mmol L{sup -1} luminal Ca had no effect on Zn transport in any section, whereas 100 mmol L{sup -1} Ca stimulated Zn uptake, by approximately threefold, into all three phases in the stomach only. There was no influence of elevated luminal Zn (10 mmol L{sup -1}) on Cd uptake in the stomach or anterior intestine, or of high Cd (10 mmol L{sup -1}) on Zn uptake in these sections. However, high [Zn] stimulated Cd transport into the blood space but inhibited accumulation in the mucosal epithelium and/or mucus-binding in the mid and posterior intestine, whereas high [Cd] exerted a reciprocal effect in the mid-intestine only. We conclude that Cd uptake occurs via an important Ca-sensitive mechanism in the stomach which is different from that at the gills, while Cd transport mechanisms in the intestine are not directly Ca-sensitive. Zn uptake does not appear to involve Ca uptake pathways, in contrast to the gills. These results are discussed in the context of other possible Cd and Zn transport pathways, and the emerging role of the stomach as an organ of divalent metal uptake.

  17. Hyperosmolar sodium chloride is toxic to cultured neurons and causes reduction of glucose metabolism and ATP levels, an increase in glutamate uptake, and a reduction in cytosolic calcium.

    Science.gov (United States)

    Morland, Cecilie; Pettersen, Mi Nguyen; Hassel, Bjørnar

    2016-05-01

    Elevation of serum sodium, hypernatremia, which may occur during dehydration or treatment with sodium chloride, may cause brain dysfunction and damage, but toxic mechanisms are poorly understood. We found that exposure to excess NaCl, 10-100mmol/L, for 20h caused cell death in cultured cerebellar granule cells (neurons). Toxicity was due to Na(+), since substituting excess Na(+) with choline reduced cell death to control levels, whereas gluconate instead of excess Cl(-) did not. Prior to cell death from hyperosmolar NaCl, glucose consumption and lactate formation were reduced, and intracellular aspartate levels were elevated, consistent with reduced glycolysis or glucose uptake. Concomitantly, the level of ATP became reduced. Pyruvate, 10mmol/L, reduced NaCl-induced cell death. The extracellular levels of glutamate, taurine, and GABA were concentration-dependently reduced by excess NaCl; high-affinity glutamate uptake increased. High extracellular [Na(+)] caused reduction in intracellular free [Ca(2+)], but a similar effect was seen with mannitol, which was not neurotoxic. We suggest that inhibition of glucose metabolism with ensuing loss of ATP is a neurotoxic mechanism of hyperosmolar sodium, whereas increased uptake of extracellular neuroactive amino acids and reduced intracellular [Ca(2+)] may, if they occur in vivo, contribute to the cerebral dysfunction and delirium described in hypernatremia. Copyright © 2016. Published by Elsevier B.V.

  18. Calcium oxide doped sorbents for CO{sub 2} uptake in the presence of SO{sub 2} at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lu, H.; Smirniotis, P.G. [University of Cincinnati, Cincinnati, OH (United States)

    2009-06-15

    There is an urgent need to understand sorbent tolerance for capturing carbon dioxide (CO{sub 2}) in the presence of sulfur dioxide (SO{sub 2}). Sulfur oxide is emitted together with CO{sub 2} from various combustion systems and can cause severe air pollution. In this study, the behavior of different dopants on the performance of calcium oxide (CaO) sorbent for capturing CO{sub 2} in the presence of SO{sub 2} was investigated. Three main sets of experiments were carried out to study carbonation and sulfation both separately and simultaneously using a thermogravimetric analyzer (TGA). The results show that SO{sub 2} reduced the capability of the sorbents for capturing CO{sub 2} because of the competition between carbonation and sulfation reactions. Formation of calcium carbonate (CaCO{sub 3}) and calcium sulfate (CaSO{sub 4}) took place upon carbonation and sulfation, respectively. Our TGA and X-ray photoelectron spectroscopy (XPS) results indicate that the carbonation is totally reversible, while this is not the case with the sulfation. The permanent residual weight gained by the sorbents during the course of sulfation is attributed to the irreversible formation of sulfate species, which is confirmed by both the TGA and XPS results. The Ce promoted CaO sorbent exhibits the best performance for CO{sub 2} capture and is the most SO{sub 2} tolerant sorbent. On the other hand, the Mn doped dopant has the strongest affinity for SO{sub 2}.

  19. EFFECT OF ALUMINUM ON PLANT GROWTH, PHOSPORUS AND CALCIUM UPTAKE OF TROPICAL RICE (Oryza sativa, MAIZE (Zea mays, AND SOYBEAN (Glycine max

    Directory of Open Access Journals (Sweden)

    D. Nursyamsi

    2018-01-01

    Full Text Available Aluminum toxicity is the most limiting factor to plant growth on acid soils. Structural and functional damages in the root system by Al decrease nutrient uptake and lead to reduce plant growth and mineral deficiency in shoot. Greenhouse experiment was conducted to study the effect of Al on plant growth, and P and Ca uptake of rice, maize, and soybean. The plants were grown in hydroponic solution added with 0, 5, 10, and 30 ppm Al, at pH 4.0. The results showed that relative growth of shoots and roots of upland rice, lowland rice, maize, and soybean decreased with an increase of Al level. However, sometimes the low Al level (5 ppm stimulated shoot and root growth of some varieties in these species. According to total AlRG30 values, which is Al concentration in solution when relative growth decreased to 50%, Al tolerance of species was in order of barley < maize < soybean < lowland rice < upland rice. For maize, Al tolerance was in the order of Arjuna < Kalingga < P 3540 < SA 5 < SA 4 < PM 95 A < SA 3 < Antasena; for soybean was Wilis < INPS < Galunggung < Kerinci < Kitamusume; for lowland rice was RD 23 < Kapuas < Cisadane < KDML 105 < IR 66 < RD 13, and for upland rice was Dodokan < JAC165 < Cirata < Orizyca sabana 6 < Danau Tempe < Laut Tawar. Based on the rank of Al tolerance, rice was the useful crop to be planted in acid soils. Antasena (maize, Kitamusume ( soybean , RD 13 (lowland rice, and Laut Tawar (upland rice were also recommended for acid soils. P and Ca concentration in shoots and roots commonly decreased with an increase of Al level. However, the low Al level stimulated absorption of P and Ca concentrations in shoots and roots.

  20. 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 ...

  1. Uptake, transport, and storage of calcium and magnesium in spruce (Picea abies [L]Karst.) and pine (Pinus silvestris L.) as affected by variable nutrition and pollutant stress

    International Nuclear Information System (INIS)

    Tuerk, S.; Forschungszentrum Juelich GmbH; Guelpen, M.; Fink, S.

    1993-01-01

    Statements about the dynamic processes of uptake, transport, and deposition of Ca and Mg in norway spruce and Scots pine are made in this paper. Concerning the storage of these elements it is shown that there are great differences in their functional importance in cell metabolism. There is evidence that the role of Mg in enzyme and protein metabolism is of far greater significance for the understanding of Mg-deficiency symptoms than its function as the central atom of the chlorophyll complexes. In regard to the transport and especially to the incorporation of Ca into the needles differences between species were evident, expressing the special status of pine among the gymnosperms. With increasing needle age an accumulation of Ca-oxalate crystals, which are physiologically inert, could be proved for the studied conifers. This was interpreted as a 'detoxication' from surplus Ca to hold constant the level of the physiologically active fraction. Accordingly, the low Ca-contents of yellowed needles are not expressing a deficiency level. It is therefore questionable, that the increase of total Ca-contents caused by liming is reflecting a physiologically improved nutritional status of conifers. The study of spruce needles exposed to ozone showed that instead of the until now considered increased Ca-efflux from the cells caused by higher membran permeability an increased Ca-influx should be assumed. The experimental exposition of spruces to simulated acid rain reveals increased leaching of Ca from the epidermal cell walls instead of the precipitation as Ca-oxalate crystals, having no major negative impact on foliage physiology. (orig./UWA) [de

  2. Calcium absorption

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  3. Calcium - ionized

    Science.gov (United States)

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

  4. Calcium Carbonate

    Science.gov (United States)

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

  5. ATP-dependent calcium transport across basal plasma membranes of human placental trophoblast

    International Nuclear Information System (INIS)

    Fisher, G.J.; Kelley, L.K.; Smith, C.H.

    1987-01-01

    As a first step in understanding the cellular basis of maternal-fetal calcium transfer, the authors examined the characteristics of calcium uptake by a highly purified preparation of the syncytiotrophoblast basal (fetal facing) plasma membrane. In the presence of nanomolar concentrations of free calcium, basal membranes demonstrated substantial ATP-dependent calcium uptake. This uptake required magnesium, was not significantly affected by Na + or K + (50 mM), or sodium azide (10 mM). Intravesicular calcium was rapidly and completely released by the calcium ionophore rapidly and completely released by the calcium ionophore A23187. Calcium transport was significantly stimulated by the calcium-dependent regulatory protein calmodulin. Placental membrane fractions enriched in endoplasmic reticulum (ER) and mitochondria also demonstrated ATP-dependent calcium uptake. In contrast to basal membrane, mitochondrial calcium uptake was completely inhibited by azide. The rate of calcium uptake was completely inhibited by azide. The rate of calcium uptake by the ER was only 20% of that of basal membranes. They conclude that the placental basal plasma membrane possesses a high-affinity calcium transport system similar to that found in plasma membranes of a variety of cell types. This transporter is situated to permit it to function in vivo in maternal-fetal calcium transfer

  6. Calcium waves.

    Science.gov (United States)

    Jaffe, Lionel F

    2008-04-12

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

  7. 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

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

    International Nuclear Information System (INIS)

    Borle, A.B.

    1990-01-01

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

  9. Retention of zinc and calcium from the human colon

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  10. Get Enough Calcium

    Science.gov (United States)

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

  11. Calcium - urine

    Science.gov (United States)

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

  12. Calcium electrotransfer for termination of transgene expression in muscle

    DEFF Research Database (Denmark)

    Hojman, Pernille; Spanggaard, Iben; Olsen, Caroline Holkman

    2011-01-01

    in vivo imaging of infrared fluorescent "Katushka" and erythropoietin evaluated by ELISA and hemoglobin. Histology was performed. Electrotransfer of Katushka and erythropoietin yielded significant expression. Maximal calcium uptake occurred after injection of Ca(2+) before electropulsing using eight high...

  13. 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,

  14. Studies on endogenous circulating calcium entry blocker and stimulator

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  15. The in vitro NADPH-dependent inhibition by CCl4 of the ATP-dependent calcium uptake of hepatic microsomes from male rats. Studies on the mechanism of the inactivation of the hepatic microsomal calcium pump by the CCl3 radical

    International Nuclear Information System (INIS)

    Srivastava, S.P.; Chen, N.Q.; Holtzman, J.L.

    1990-01-01

    The hepatotoxicity of CCl4 is mediated through its initial reduction by cytochrome P-450 to the CCl3 radical. This radical then damages important metabolic systems such as the ATP-dependent microsomal Ca2+ pump. Previous studies from our laboratory on isolated microsomes have shown that NADPH in the absence of toxic agents inhibits this pump. We have now found in in vitro incubations that CCl4 (0.5-2.5 mM) enhanced the NADPH-dependent inhibition of Ca2+ uptake from 28% without CCl4 to a maximum of 68%. These concentrations are in the range found in the livers and blood of lethally intoxicated animals and are toxic to cultured hepatocytes. The inhibition of Ca2+ uptake was due both to a decrease in the Ca2(+)-dependent ATPase and to an enhanced release of Ca2+ from the microsomes. The NADPH-dependent CCl4 inhibition was greater under N2 and was totally prevented by CO. GSH (1-10 mM) added during the incubation with CCl4 prevented the inhibition. This protection was also seen when the incubations were performed under nitrogen. When samples were preincubated with CCl4, the CCl4 metabolism was stopped, and then the Ca2+ uptake was determined; GSH reversed the CCl4 inhibition of Ca2+ uptake. This reversal showed saturation kinetics for GSH with two Km values of 0.315 and 93 microM when both the preincubation and the Ca2+ uptake were performed under air, and 0.512 and 31 microM when both were performed under nitrogen. Cysteine did not prevent the NADPH-dependent CCl4 inhibition of Ca2+ uptake. CCl4 increased lipid peroxidation in air, but no lipid peroxidation was seen under nitrogen. Lipid peroxidation was only modestly reversed by GSH. GSH did not remove 14C bound to samples preincubated with the 14CCl4

  16. Na+ -K+ pump activity in rat peritoneal mast cells: inhibition by extracellular calcium

    DEFF Research Database (Denmark)

    Knudsen, Torben; Johansen, Torben

    1989-01-01

    1. Pure populations of rat peritoneal mast cells were used to study cellular potassium uptake. The radioactive potassium analogue, 86rubidium, was used as a tracer for potassium for measurements of the activity of the cellular potassium uptake process. 2. The ouabain-sensitive and the ouabain......-resistant potassium (86rubidium) uptake of mast cells incubated in the presence of calcium, 1 mmol l-1, were very low, 52 and 147 pmol per 10(6) cells min-1. 3. Calcium-deprivation of the cells uncovered a large capacity ouabain-sensitive potassium (86rubidium) uptake mechanism. The activity of the uptake mechanism...... was decreased by reintroduction of calcium into the cell suspension, and it was dependent on cellular energy metabolism, temperature and pH. 4. The potassium (86rubidium) uptake of mast cells incubated in a calcium-free medium occurs through an active and ouabain-sensitive mechanism that has the nature...

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

    Science.gov (United States)

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

    1985-08-01

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

  18. Angiotensin effects on calcium and steroidogenesis in adrenal glomerulosa cells

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  19. The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

    Directory of Open Access Journals (Sweden)

    Yajin Liao

    2017-02-01

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

  20. Calcium blood test

    Science.gov (United States)

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

  1. 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 ...

  2. 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 ...

  3. Calcium carbonate overdose

    Science.gov (United States)

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

  4. 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 ...

  5. 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 ...

  6. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    Science.gov (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  7. Deposition of strontium and calcium in snail shell

    Energy Technology Data Exchange (ETDEWEB)

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

    1965-07-03

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

  8. Calcium in Urine Test

    Science.gov (United States)

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

  9. Transcellular transport of calcium

    Energy Technology Data Exchange (ETDEWEB)

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

    1976-01-01

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

  10. Regulation of intracellular calcium in resting and stimulated rat basophilic leukemia cells

    International Nuclear Information System (INIS)

    Mohr, F.C.

    1988-01-01

    Intracellular calcium regulation was studied in a cell line of mast cells, the rat basophilic leukemia (RBL) cells with the purpose of determining (1) The properties of the plasma membrane calcium permeability pathway and (2) The role of intracellular calcium stores. The first set of experiments showed that depolarization did not induce calcium entry or secretion in resting cells and did inhibit antigen-stimulated calcium uptake and secretion. In the second set of experiments the ionic basis of antigen-induced depolarization was studied using the fluorescent potential-sensitive probe bis-oxonol. The properties of the calcium entry pathway were more consistent with a calcium channel than a calcium transport mechanism such as Na:Ca exchange. The third set of experiments examined the effects of the proton ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on RBL cells. CCCP inhibited antigen-stimulated 45 Ca uptake and secretion by depolarizing the plasma membrane

  11. Characterization of branchial transepithelial calcium fluxes in freshwater trout, Salmo gairdneri

    International Nuclear Information System (INIS)

    Perry, S.F.; Flik, G.

    1988-01-01

    Experiments were performed to determine whether gill transepithelial calcium fluxes in the freshwater trout (Salmo gairdneri) are passive or require active transport and to characterize the mechanism involved. A comparison of the in vivo unidirectional flux ratios with the flux ratios calculated according to the transepithelial electrochemical gradients revealed that calcium uptake from the water requires active transport of Ca 2+ . The inhibition of calcium uptake by external lanthanum, the specific deposition of lanthanum on the apical surface of chloride cells, and the favorable electrochemical gradient for calcium across the apical membrane suggest that the initial step in branchial calcium uptake is the passive entry of calcium into the cytosol of chloride cells through apical channels that are permeable to calcium. The study of gill basolateral plasma membrane vesicles demonstrated the existence of a high-affinity calmodulin-dependent calcium-transporting system. This system actively transports calcium from the cytosol of chloride cells into the plasma against a sizeable electrochemical gradient, thereby completing the transepithelial uptake of calcium. Calcium efflux occurs passively through paracellular pathways between chloride cells and adjacent pavement cells or between neighboring pavement cells

  12. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    DEFF Research Database (Denmark)

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    monolayers with a permeability of 5.7 × 10−5 cm sec−1 compared to an apical to basolateral permeability of 1.3 × 10−5 cm sec-1. The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6–1.6. The presence of telmisartan......Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake...... of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1...

  13. Phosphocitrate inhibits mitochondrial and cytosolic accumulation of calcium in kidney cells in vivo.

    OpenAIRE

    Tew, W P; Malis, C D; Howard, J E; Lehninger, A L

    1981-01-01

    Synthetic 3-phosphocitrate, an extremely potent inhibitor of calcium phosphate crystallization as determined in a nonbiological physical-chemical assay, has many similarities to a mitochondrial factor that inhibits crystallization of nondiffracting amorphous calcium phosphate. In order to determine whether phosphocitrate can prevent uptake and crystallization of calcium phosphate in mitochondria in vivo, it was administered intraperitoneally to animals given large daily doses of calcium gluco...

  14. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping

    2012-01-01

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

  15. Calcium fluoride

    International Nuclear Information System (INIS)

    King, C.W.; Nestor, O.H.

    1989-01-01

    A new process for producing large, single, oriented crystals of calcium fluoride (CaF 2 ) has been developed which overcomes the limitations of current growing methods. This process has been reduced to practice and has yielded oriented crystals 17.5 x 17.5 x 5 cm 3 . Currently nearing completion is a system for producing 35 x 35 x 7.5 cm 3 single crystals. A scale up to one-meter-square is considered feasible. This crystal growing process makes possible the fabrication of very large CaF 2 windows. Suitability for very high power lasers, however, requires attention to properties beyond mere size. A process to generate higher purity growth stock (starting material) was also developed. The additional purification of the growth stock contributes to lower bulk absorption, the absence of color centers and increased radiation hardness. Also identified were several specific impurities which correlate with radiation hardness. A correlation was found between color centers induced by laser radiation and ionizing radiation. Other CaF 2 crystal properties such as tensile strength, absorption and laser damage thresholds were studied and are discussed

  16. Characterization of transport of calcium by microsomal membranes from roots maize

    International Nuclear Information System (INIS)

    Vaughan, M.A.

    1985-01-01

    This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the 45 Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl 2 , 50 μM CaCl 2 , at 23 0 C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine ( ... for each thyroid uptake is five minutes or less. top of page What will I experience during ...

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... uptake measurements are obtained at different times. For example, you may have uptake measurements at four to ... medicine procedures can be time consuming. It can take several hours to days for the radiotracer to ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Scan and Uptake Thyroid scan and uptake uses small amounts of radioactive materials called radiotracers, a special ... is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine ...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. It is a measurement of ... potential to identify disease in its earliest stages as well as a patient’s immediate response to therapeutic ...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... known as a thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. ... eating can affect the accuracy of the uptake measurement. Jewelry and other metallic accessories should be left ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that ...

  3. Calcium and magnesium determination

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.

    1982-01-01

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

  4. 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 ...

  5. 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 ...

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake will begin several hours to 24 hours later. Often, two separate uptake ...

  7. 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.

  8. Calcium handling by platelets from normal and malignant hyperthermia-susceptible pigs

    International Nuclear Information System (INIS)

    Miller, K.E.; Brooks, R.R.; Bonk, K.R.; Carpenter, J.F.

    1991-01-01

    Platelets from normal and malignant hyperthermia (MH)-susceptible pigs were evaluated for differences in 45 calcium uptake in the absence or presence of caffeine, halothane, or halothane and caffeine together. There were no statistically significant differences in basal or halothane-inhibited calcium uptake by platelets from either source. There was a small statistically significant difference in calcium uptake between platelets from normal and MH-susceptible pigs in the presence of 16 mM caffeine and 0.5% halothane. Calcium uptake by platelets from one pedigree of MH-susceptible pigs were stimulated in a concentration-dependent manner by caffeine. These data suggest that exposure of platelets to caffeine may have potential for identifying MH-susceptibility

  9. 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

  10. Effects of the hexahydroxyhexane myoinositol on bone uptake of radiocalcium in rats: Effect of inositol and vitamin D2 on bone uptake of 45Ca in rats

    International Nuclear Information System (INIS)

    Angeloff, L.G.; Skoryna, S.C.; Henderson, I.W.D.

    1977-01-01

    The objective of this study was to investigate the effects of inositol and vitamin D 2 on bone uptake of 45 Ca in rats. The radioactive calcium was administered to young rats by orogastric intubation (2 μci/100 g body weight (b.wt.)) with inositol (20 mg/100 g b.wt) and/or vitamin D 2 (500 IU/100g b.wt) to normal rats. Bone uptake of 45 Ca was measured after 24 hours by standard technique. Inositol alone produced a 48% increase in calcium uptake. It is concluded that inositol significantly increases bone uptake to radioactive calcium (P>0.005). Simultaneous administration of vitamin D 2 decreases the effect of inositol considerably, while vitamin D 2 has no significant effect. (author)

  11. Biodegradation and moisture uptake modified starch-filled Linear ...

    African Journals Online (AJOL)

    Sixteen different modified-cassava starch-LLDPE blends containing starch in the range of 10-40% by weight were prepared. Calcium chloride, D-glucose, chloroform and alumina were differently used as modifying agents. The Moisture uptake and biodegradation of each of the composites were investigated. Both of these ...

  12. Thyroid uptake test

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    The uptake of radioiodine by the thyroid gland is altered by the iodine content of diet or drugs. American diet has a high iodine content because each slice of the white bread contains nearly 150μg of iodine due to the bleaching process employed in the production of the bread. This carrier content of iodine reduces the uptake so much, that the normal American uptakes are usually three to four times lower than the uptakes in the developing countries. The other drawback of the thyroid uptake test is that it is affected by the iodine containing drugs. Anti-diarrhoea medications are quire common in the developing countries and many of them contain iodine moiety. Without a reliable drug history, a low thyroid uptake value may lead to a misleading conclusion

  13. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

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

  14. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Lothenbach, B.; L'Hopital, E.; Nied, D.; Achiedo, G.; Dauzeres, A.

    2015-01-01

    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 29 Si 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 Q 3 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 Ca 2+ (1.1 Angstrom) compared to Mg 2+ (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

  15. Tansley Review No. 104, Calcium Physiology and Terrestrial Ecosystem Processes

    Science.gov (United States)

    S.B. McLaughlin; R. Wimmer

    1999-01-01

    Calcium occupies a unique position among plant nutrients both chemically and functionally. Its chemical properties allow it to exist in a wide range of binding states and to serve in both structural and messenger roles. Despite its importance in many plant processes, Ca mobility is low, making Ca uptake and distribution rate a limiting process for many key plant...

  16. Calcium channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar

    2005-04-01

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

  17. 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...

  18. Mitochondrial Calcium Dysregulation Contributes to Dendrite Degeneration Mediated by PD/LBD-Associated LRRK2 Mutants.

    Science.gov (United States)

    Verma, Manish; Callio, Jason; Otero, P Anthony; Sekler, Israel; Wills, Zachary P; Chu, Charleen T

    2017-11-15

    Mutations in leucine-rich repeat kinase 2 (LRRK2) contribute to development of late-onset familial Parkinson's disease (PD), with clinical features of motor and cognitive dysfunction indistinguishable from sporadic PD. Calcium dysregulation plays an important role in PD pathogenesis, but the mechanisms of neurodegeneration remain unclear. Recent reports indicate enhanced excitatory neurotransmission in cortical neurons expressing mutant LRRK2, which occurs before the well-characterized phenotype of dendritic shortening. As mitochondria play a major role in the rapid buffering of cytosolic calcium, we hypothesized that altered mitochondrial calcium handling contributes to dendritic retraction elicited by the LRRK2-G2019S and -R1441C mutations. In primary mouse cortical neurons, we observed increased depolarization-induced mitochondrial calcium uptake. We found that expression of mutant LRRK2 elicited transcriptional upregulation of the mitochondrial calcium uniporter (MCU) and the mitochondrial calcium uptake 1 protein (MICU1) with no change in levels of the mitochondrial calcium antiporter NCLX. Elevated MCU and MICU1 were also observed in LRRK2-mutated patient fibroblasts, along with increased mitochondrial calcium uptake, and in postmortem brains of sporadic PD/PDD patients of both sexes. Transcriptional upregulation of MCU and MICU1 was caused by activation of the ERK1/2 (MAPK3/1) pathway. Inhibiting ERK1/2 conferred protection against mutant LRRK2-induced neurite shortening. Pharmacological inhibitors or RNAi knockdown of MCU attenuated mitochondrial calcium uptake and dendritic/neuritic shortening elicited by mutant LRRK2, whereas expression of a constitutively active mutant of NCLX that enhances calcium export from mitochondria was neuroprotective. These data suggest that an increased susceptibility to mitochondrial calcium dysregulation contributes to dendritic injury in mutant LRRK2 pathogenesis. SIGNIFICANCE STATEMENT Cognitive dysfunction and dementia are

  19. Calcium Channel Blockers

    Science.gov (United States)

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

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. ...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ...

  2. Activation of purified calcium channels by stoichiometric protein phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Nunoki, K.; Florio, V.; Catterall, W.A. (Univ. of Washington, Seattle (USA))

    1989-09-01

    Purified dihydropyridine-sensitive calcium channels from rabbit skeletal muscle were reconstituted into phosphatidylcholine vesicles to evaluate the effect of phosphorylation by cyclic AMP-dependent protein kinase (PK-A) on their function. Both the rate and extent of {sup 45}Ca{sup 2+} uptake into vesicles containing reconstituted calcium channels were increased severalfold after incubation with ATP and PK-A. The degree of stimulation of {sup 45}Ca{sup 2+} uptake was linearly proportional to the extent of phosphorylation of the alpha 1 and beta subunits of the calcium channel up to a stoichiometry of approximately 1 mol of phosphate incorporated into each subunit. The calcium channels activated by phosphorylation were determined to be incorporated into the reconstituted vesicles in the inside-out orientation and were completely inhibited by low concentrations of dihydropyridines, phenylalkylamines, Cd{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}. The results demonstrate a direct relationship between PK-A-catalyzed phosphorylation of the alpha 1 and beta subunits of the purified calcium channel and activation of the ion conductance activity of the dihydropyridine-sensitive calcium channels.

  3. Activation of purified calcium channels by stoichiometric protein phosphorylation

    International Nuclear Information System (INIS)

    Nunoki, K.; Florio, V.; Catterall, W.A.

    1989-01-01

    Purified dihydropyridine-sensitive calcium channels from rabbit skeletal muscle were reconstituted into phosphatidylcholine vesicles to evaluate the effect of phosphorylation by cyclic AMP-dependent protein kinase (PK-A) on their function. Both the rate and extent of 45 Ca 2+ uptake into vesicles containing reconstituted calcium channels were increased severalfold after incubation with ATP and PK-A. The degree of stimulation of 45 Ca 2+ uptake was linearly proportional to the extent of phosphorylation of the alpha 1 and beta subunits of the calcium channel up to a stoichiometry of approximately 1 mol of phosphate incorporated into each subunit. The calcium channels activated by phosphorylation were determined to be incorporated into the reconstituted vesicles in the inside-out orientation and were completely inhibited by low concentrations of dihydropyridines, phenylalkylamines, Cd 2+ , Ni 2+ , and Mg 2+ . The results demonstrate a direct relationship between PK-A-catalyzed phosphorylation of the alpha 1 and beta subunits of the purified calcium channel and activation of the ion conductance activity of the dihydropyridine-sensitive calcium channels

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

    Directory of Open Access Journals (Sweden)

    Xixi Cai

    2016-12-01

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

  5. Effect of heat shock on ultrastructure and calcium distribution in Lavandula pinnata L. glandular trichomes.

    Science.gov (United States)

    Huang, S S; Kirchoff, B K; Liao, J P

    2013-02-01

    The effects of heat shock (HS) on the ultrastructure and calcium distribution of Lavandula pinnata secretory trichomes are examined using transmission electron microscopy and potassium antimonate precipitation. After 48-h HS at 40°C, plastids become distorted and lack stroma and osmiophilic deposits, the cristae of the mitochondria become indistinct, the endoplasmic reticulum acquires a chain-like appearance with ribosomes prominently attached to the lamellae, and the plasma and organelle membranes become distorted. Heat shock is associated with a decrease in calcium precipitates in the trichomes, while the number of precipitates increases in the mesophyll cells. Prolonged exposure to elevated calcium levels may be toxic to the mesophyll cells, while the lack of calcium in the glands cell may deprive them of the normal protective advantages of elevated calcium levels. The inequality in calcium distribution may result not only from uptake from the transpiration stream, but also from redistribution of calcium from the trichomes to the mesophyll cells.

  6. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

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

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibi...

  7. 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...

  8. Cerebroprotective activity of U-50488H: Relationship to interactions with excitatory amino acids and calcium

    International Nuclear Information System (INIS)

    Camacho Ochoa, M.

    1987-01-01

    The mechanism underlying the anticonvulsant and cerebroprotective activity of U-50488H was evaluated using 45 Ca ++ uptake in rat Ficoll purified synaptosomes, ( 3 H)-2-deoxyglucose uptake in selected mouse brain regions, ( 3 H)kainic acid binding to mouse forebrain synaptic membranes and incidence of KA-induced lesions in the CA3 region of the mouse hippocampus. U-50488H causes reduction in K + -evoked 45 Ca ++ uptake. These effects are comparable to those of the calcium channel blockers verapamil and nifedipine and seem to be related to calcium dependent mechanisms. Changes in saturability, specificity and dissociation constant values of kainic acid receptor binding were demonstrated in the presence of U-50488H at concentrations similar to those used in 45 Ca ++ uptake studies and in the presence of calcium and chloride ions

  9. Calcium metabolism in birds.

    Science.gov (United States)

    de Matos, Ricardo

    2008-01-01

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

  10. Calcium Biofortification: Three Pronged Molecular Approaches for Dissecting Complex Trait of Calcium Nutrition in Finger Millet (Eleusine coracana) for Devising Strategies of Enrichment of Food Crops.

    Science.gov (United States)

    Sharma, Divya; Jamra, Gautam; Singh, Uma M; Sood, Salej; Kumar, Anil

    2016-01-01

    Calcium is an essential macronutrient for plants and animals and plays an indispensable role in structure and signaling. Low dietary intake of calcium in humans has been epidemiologically linked to various diseases which can have serious health consequences over time. Major staple food-grains are poor source of calcium, however, finger millet [ Eleusine coracana (L.) Gaertn.], an orphan crop has an immense potential as a nutritional security crop due to its exceptionally high calcium content. Understanding the existing genetic variation as well as molecular mechanisms underlying the uptake, transport, accumulation of calcium ions (Ca 2+ ) in grains is of utmost importance for development of calcium bio-fortified crops. In this review, we have discussed molecular mechanisms involved in calcium accumulation and transport thoroughly, emphasized the role of molecular breeding, functional genomics and transgenic approaches to understand the intricate mechanism of calcium nutrition in finger millet. The objective is to provide a comprehensive up to date account of molecular mechanisms regulating calcium nutrition and highlight the significance of bio-fortification through identification of potential candidate genes and regulatory elements from finger millet to alleviate calcium malnutrition. Hence, finger millet could be used as a model system for explaining the mechanism of elevated calcium (Ca 2+ ) accumulation in its grains and could pave way for development of nutraceuticals or designer crops.

  11. Strontium and calcium accumulation in fish as affected by food composition

    International Nuclear Information System (INIS)

    Ophel, I.L.; Judd, J.M.

    1976-01-01

    Radioactive tracers ( 85 Sr and 47 Ca) were used to investigate the effects of food composition on the accumulation of strontium and calcium by fish and their discrimination between these two elements. The total amount of calcium assimilated by fish was the same for all experimental conditions. Calcium not obtainable from food was absorbed from the water, even when the water concentration was less than 10 mg Ca/l. The major discriminatory process occurred during direct (gill) uptake from water. Gut uptake provided least discrimination against strontium. Strontium content of fish was closely related to the Sr/Ca ratio in their food. Strontium assimilation was found to be a function of: the Sr/Ca ratios of food and water, the amounts of calcium derived from each source and the biological discrimination against strontium relative to calcium

  12. Comparison of chromium and nickel uptake of plants grown in different soils

    Energy Technology Data Exchange (ETDEWEB)

    Vago, I. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Gyoeri, Z. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Loch, J. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary)

    1996-03-01

    The chromium and nickel uptake of ryegrass has been examined in pot experiments in extremely different soils, poor sandy and fertile black chernozem. The effect of calcium carbonate doses and nitrogen supply on heavy metal uptake of the plant has been studied for chromium and nickel loadings (0-100 mg/kg Cr{sup 3+} or Ni{sup 2+}) applied as inorganic salts. The ability to uptake Cr{sup 3+} and Ni{sup 2+} differs significantly and is highly affected by the characteristics of soils, and depends on the metal investigated. The heavy metal uptake of the plant differs significantly in acid, colloid deficient sandy soils; while artificial chromium contamination did not modify the dry-matter production in the pots in either soil, a large quantity of nickel reduced the yields significantly. Nitrogen application did not change significantly the uptake of heavy metals. Lime application reduced the Ni{sup 2+} uptake of plants considerably, especially in sandy soil. In case of a calcium carbonate addition the dry-matter production of the plant was not affected by nickel. In chernozem soil the effect of lime application - i.e., the reduction of nickel uptake - was of a lesser degree. The significantly lesser Cr{sup 3+} uptake was further limited by a calcium carbonate application for both soils studied. A graphic presentation of these effects is given. (orig.). With 3 figs., 3 tabs.

  13. Calcium electrotransfer for termination of transgene expression in muscle

    DEFF Research Database (Denmark)

    Hojman, Pernille; Spanggaard, Iben; Olsen, Caroline Holkman

    2011-01-01

    Gene electrotransfer is expanding in clinical use, thus we have searched for an emergency procedure to stop transgene expression in case of serious adverse events. Calcium is cytotoxic at high intracellular levels, so we tested effects of calcium electrotransfer on transgene expression in muscle....... A clinical grade calcium solution (20 μl, 168 mM) was injected into transfected mouse or rat tibialis cranialis muscle. Ca(2+) uptake was quantified using calcium 45 ((45)Ca), and voltage and time between injection and pulsation were varied. Extinction of transgene expression was investigated by using both...... voltage pulses of 1000 V/cm. Using these parameters, in vivo imaging showed that transgene expression significantly decreased 4 hr after Ca(2+) electrotransfer and was eliminated within 24 hr. Similarly, serum erythropoietin was reduced by 46% at 4 hr and to control levels at 2 days. Histological analyses...

  14. 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

  15. Effect of high calcium concentration influents on enhanced biological phosphorus removal process

    International Nuclear Information System (INIS)

    Montoya Martinez, T.; Aguado Garcia, D.; Ferrer Polo, J.

    2010-01-01

    In this work, the effect of calcium concentration in wastewater on the polyphosphate accumulating organisms (PAO) is investigated as well as its influence in PAO metabolism, specifically in the Y P O4 (ratio between phosphorus release and acetic acid uptake). For this study a sequencing batch reactor (SBR) anaerobic-aerobic was used, in which the PAO enriched biomass was exposed to different calcium concentrations in the influent wastewater. The results indicate that until a given calcium level in the influent wastewater (35 mg Ca/l) the metabolism is not affect, but higher calcium concentrations lead to significant Y P O4 decline. (Author) 18 refs.

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information about your thyroid’s size, shape, position and function that is often unattainable using other imaging procedures. ... thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. Nuclear medicine is ...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... which are encased in metal and plastic and most often shaped like a box, attached to a ... will I experience during and after the procedure? Most thyroid scan and thyroid uptake procedures are painless. ...

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  20. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential ... or imaging device that produces pictures and provides molecular information. The thyroid scan and thyroid uptake provide ...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Actual scanning time for each thyroid uptake is five minutes or less. top of page What will ... diagnostic procedures have been used for more than five decades, and there are no known long-term ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top ... Scan and Uptake Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... When radiotracer is taken by mouth, in either liquid or capsule form, it is typically swallowed up ... radioactive iodine (I-123 or I-131) in liquid or capsule form to swallow. The thyroid uptake ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... RAIU) is also known as a thyroid uptake. It is a measurement of thyroid function, but does ... they offer the potential to identify disease in its earliest stages as well as a patient’s immediate ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for several hours before your exam because eating can affect the accuracy of the uptake measurement. Jewelry ... small hand-held device resembling a microphone that can detect and measure the amount of the radiotracer ...

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? Most thyroid scan and thyroid uptake ... you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special instructions ...

  7. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is ... computer, create pictures offering details on both the structure and function of organs and tissues in your ...

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... its radioactivity over time. It may also pass out of your body through your urine or stool ...

  9. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... procedures within the last two months that used iodine-based contrast material. Your doctor will instruct you ... a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is also known as a ...

  10. Role of magnesium on the biomimetic deposition of calcium phosphate

    Science.gov (United States)

    Sarma, Bimal K.; Sarma, Bikash

    2016-10-01

    Biomimetic depositions of calcium phosphate (CaP) are carried out using simulated body fluid (SBF), calcifying solution and newly developed magnesium containing calcifying solution. Calcium phosphate has a rich phase diagram and is well known for its excellent biocompatibility and bioactivity. The most common phase is hydroxyapatite (HAp), an integral component of human bone and tooth, widely used in orthopedic and dental applications. In addition, calcium phosphate nanoparticles show promise for the targeted drug delivery. The doping of calcium phosphate by magnesium, zinc, strontium etc. can change the protein uptake by CaP nanocrystals. This work describes the role of magnesium on the nucleation and growth of CaP on Ti and its oxide substrates. X-ray diffraction studies confirm formation of HAp nanocrystals which closely resemble the structure of bone apatite when grown using SBF and calcifying solution. It has been observed that magnesium plays crucial role in the nucleation and growth of calcium phosphate. A low magnesium level enhances the crystallinity of HAp while higher magnesium content leads to the formation of amorphous calcium phosphate (ACP) phase. Interestingly, the deposition of ACP phase is rapid when magnesium ion concentration in the solution is 40% of calcium plus magnesium ions concentration. Moreover, high magnesium content alters the morphology of CaP films.

  11. Selective uptake of manganese in seawater by hybrid microcapsules

    International Nuclear Information System (INIS)

    Kuzumaki, Takenori; Yan, Wu; Mimura, Hitoshi; Niibori, Yuichi

    2008-01-01

    The selective separation and recovery of low concentrated elements in seawater are very important subjects for the advancement of environmental monitoring. Selective uptake of manganese from seawater was carried out by using two kinds of microcapsules (MCs) including activated carbon (AC) and insoluble tannin (T). The adsorbents, AC and T, having affinity for manganese, were enclosed into MCs (ACMS, TMC) by sol-gel method using matrices of biopolymer (calcium alginate gel polymer, CaALG). The uptake properties and selectivity of Mn 2+ (1 ppm) for MCs were examined by batch method. Relatively large uptake percentages of Mn 2+ above 80% were obtained within 1 h, and the uptake percentage above 80% was kept at pH 3-6. The uptake order was found to be T, AC, CaALG > ACMC, TMC. The uptake of Mn 2+ decreased with increasing Na + ion concentration. This tendency depends on the swelling property of CaALG; it tends to solate in the presence of highly concentrated Na + ions. The manganese ions were adsorbed on CaALG, ACMC and TMC from seawater containing 1,000 ppm Mn 2+ . ACMC and TMC had selectivity to Mn 2+ , and, especially, the matrices of CaALG also had an excellent uptake and selectivity properties. (author)

  12. CBL-CIPK network for calcium signaling in higher plants

    Science.gov (United States)

    Luan, Sheng

    Plants sense their environment by signaling mechanisms involving calcium. Calcium signals are encoded by a complex set of parameters and decoded by a large number of proteins including the more recently discovered CBL-CIPK network. The calcium-binding CBL proteins specifi-cally interact with a family of protein kinases CIPKs and regulate the activity and subcellular localization of these kinases, leading to the modification of kinase substrates. This represents a paradigm shift as compared to a calcium signaling mechanism from yeast and animals. One example of CBL-CIPK signaling pathways is the low-potassium response of Arabidopsis roots. When grown in low-K medium, plants develop stronger K-uptake capacity adapting to the low-K condition. Recent studies show that the increased K-uptake is caused by activation of a specific K-channel by the CBL-CIPK network. A working model for this regulatory pathway will be discussed in the context of calcium coding and decoding processes.

  13. DIHYDROPYRIDINE CALCIUM- CHANNELBLOCKERSFOR ...

    African Journals Online (AJOL)

    Furthermore, the controversy over the role of calci~-channel blockers as first-line ..... group trials while fully accounting for placebo effects as well as interindividual ..... Reducing calcium overload in the ischemic brain. N Engl JMed. 1999; 341 ...

  14. Calcium and Your Child

    Science.gov (United States)

    ... calcium-set tofu edamame (soybeans) broccoli, collard greens, kale, chard, Chinese cabbage, and other leafy greens almonds ... more dark green, leafy vegetables (such as broccoli, kale, collard greens, or Chinese cabbage) with meals. Kids ...

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

    International Nuclear Information System (INIS)

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

    1978-01-01

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

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

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  17. Calcium transport across the membrane of Paramecium caudatum (protozoa)

    International Nuclear Information System (INIS)

    Martinac, B.

    1980-06-01

    Calcium transport across the membrane of Paramecium caudatum was studied by measuring calcium uptake and release by means of flow-through-technique, which was developed especially for this purpose. The method allows continuous flow of the cells suspension with radioactive and inactive solution, respectively, combined with simultaneous electrical stimulation of the cells by means of extracellular electrodes. The results obtained were compared to and interpreted according to behavioral patterns of Paramecium, which were registered by the time exposure dark-field macrophotographic technique under the same experimental conditions. (orig.) [de

  18. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  19. [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

  20. Biphasic stimulation of cellular calcium concentration by 3,5,3'-triiodothyronine in rat thymocytes

    International Nuclear Information System (INIS)

    Segal, J.

    1988-01-01

    3,5,3'-Triiodothyronine (T 3 ) produced a rapid and transient increase in 45 Ca uptake and cytoplasmic free calcium concentration in rat thymocytes, which is the most rapid effect of T 3 in this system. This effect was manifested in cells suspended in medium containing 1 mM calcium. The T 3 effect on 45 Ca uptake was evident at 15-30 s, reached maximum at 30-60 s, and returned to control values at 5 min. The T 3 effect on cytoplasmic free calcium concentration was seen after 30 s, reached maximum at 7 min, and returned to control values after 24 min. In cells suspended in Ca 2+ -free medium, T 3 produced a similar rapid increase in 45 Ca uptake, which was sustained for at least 60 min, but T 3 failed to change cytoplasmic free calcium concentration. Alprenolol (10 μM) blocked the stimulatory effects of T 3 on these two functions in a similar fashion. From these results, the authors suggest that in rat thymocytes T 3 influences cellular calcium economy through a biphasic mechanism in which T 3 first increases calcium uptake which, in turn, if followed by a release of calcium from intracellular pool(s), resulting in a further increase in cytoplasmic free calcium concentration and the activation of Ca 2+ -regulated systems. Moreover, the present study provides further support for the postulate that in the rat thymocyte calcium serves as the first messenger for the plasma membrane-mediated stimulatory effects of T 3 on several metabolic functions

  1. 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

  2. Thyroid uptake software

    International Nuclear Information System (INIS)

    Alonso, Dolores; Arista, Eduardo

    2003-01-01

    The DETEC-PC software was developed as a complement to a measurement system (hardware) able to perform Iodine Thyroid Uptake studies. The software was designed according to the principles of Object oriented programming using C++ language. The software automatically fixes spectrometric measurement parameters and besides patient measurement also performs statistical analysis of a batch of samples. It possesses a PARADOX database with all information of measured patients and a help system with the system options and medical concepts related to the thyroid uptake study

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  4. Uptake indexes of 90Sr in the countries with various nutrition types

    International Nuclear Information System (INIS)

    Knizhnikov, V.N.; Marej, A.N.; Borisov, B.K.; Petukhova, Eh.V.

    1980-01-01

    90 Sr uptake in the human organism in the USSR and a number of countries with a western type of nitrition is studied for the period from 1963 to 1971. The following indexes are presented: the observed ratio (OR), which is 90 Sr in a skeleton/ 90 Sr in a diet pCi/gCa/pCi/gCa. This index depends largely on the level of calcium content in the diet. The index of buildup multiplicity is used to characterize 90 Sr uptake irrespective of calcium content in the diet. These indexes are used to compare 90 Sr uptake in France, USA, USSR, FRG. Factors which affect 90 Sr uptake connected with nutrition peculiarities and 90 Sr form in the diet, are presented

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake ...

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... information. The thyroid scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is a gland in the neck that controls metabolism , a chemical process that regulates the rate at which the body ...

  7. Radioactive uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Horak, O

    1986-01-01

    The fundamentals of radionuclide uptake by plants, both by leaves and roots are presented. Iodine, cesium, strontium and ruthenium are considered and a table of the measured concentrations in several agricultural plants shortly after the Chernobyl accident is presented. Another table gives the Cs and Sr transfer factors soil plants for some plants. By using them estimates of future burden can be obtained.

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  9. Thyroid Scan and Uptake

    Science.gov (United States)

    ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: ... of a typical probe counter used for thyroid uptake exams. The patient sits with the camera directed at the neck for five minutes, and then the leg for ...

  10. 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)

    Tuerk, S.H.

    1995-12-01

    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 45 Ca 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 ( 45 Ca) 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.) [de

  11. Partial purification of the ATP-driven calcium pump of Streptococcus sanguis

    International Nuclear Information System (INIS)

    Lynn, A.R.; Rosen, B.P.

    1986-01-01

    ATP-dependent transport of calcium has been observed in several species of streptococci as uptake of 45 Ca 2+ into everted membrane vesicles. Membranes from Streptococcus sanguis and Streptococcus faecalis were solubilized with octyl-β-D-glucoside or Triton X-100, and the extracts reconstituted into proteoliposomes containing Escherichia coli or soybean phospholipid. Calcium transport in reconstituted proteoliposomes was insensitive to the ionophores nigericin and valinomycin and was unaffected by the F 0 F 1 inhibitor N,N'-dicyclohexylcarbodiimide. Uptake was inhibited by ortho-vanadate with a K/sub i/ in the micromolar range. These results demonstrate that the reconstituted transport activities are not the result of ATP-driven proton pumping via the F 0 F 1 coupled to a calcium/proton antiporter and suggest that existence of a calcium translocating ATPase. Partial purification of the transport activity from Streptococcus sanguis has been achieved using density gradient centrifugation and FPLC

  12. Influence of lead injection on calcium-45 distribution in hard tissues of rats

    International Nuclear Information System (INIS)

    Sato, Makoto

    1978-01-01

    This study determines the relationship between calcium distribution in hard tissues and age. The distribution of calcium was examined by using calcium-45 as tracer. Further, influences of such environmental toxic heavy metals as lead, cadmium and mercury upon calcium metabolism were determined. According to checks performed on 3-week-old rats, calcium-45 distributions in hard tissues from 6 hours to 6 days after injection were greater in the following tissues in the order listed: femurs, incisors, molars. In 2-week-old rats, the calcium distributions throughout the body were about the same. In 3-week-old rats, however, they were graded in descending order from femur to incisors, and then to molars. In rats of 18 weeks or more, the distribution of calcium-45 in the femur decreased. A slow increase was noted in calcium-45 deposits in the incisors of rats of four or more weeks; this increase remained constant at a very low level in rats of more than eight weeks. Calcium-45 distribution in rats of 61 weeks of age was graded in this descending order: incisors, femurs, and molars. In the group injected with calcium-45 and lead acetate, calcium-45 distribution was significantly less in 3-week-old than in 3-month-old rats. The following are percentages of calcium-45 distribution in rats to which 100 mg/kg of lead (equivalent of 1/3 of LD 50 were injected, when 100-percent distribution is assumed for controls; 3-week-old rats: femur 48 percent, incisors 49 percent, and molars 40 percent, 3-month-old rats: femurs 73 percent, incisors 67 percent, and molars 71 percent. No difference was observed in calcium-45 uptake between rats to whom injections of cadmium and mercury equivalent to 1/3 of a dose of LD 50 had been administered and rats who received only a single injection of calcium-45. (auth.)

  13. The effect of mitochondrial inhibitors on calcium homeostasis in tumor mast cells

    International Nuclear Information System (INIS)

    Mohr, F.C.; Fewtrell, C.

    1990-01-01

    The depletion of intracellular ATP by mitochondrial inhibitors in a glucose-free saline solution inhibited antigen-stimulated 45Ca uptake, the rise in cytoplasmic calcium, measured by fura-2, and secretion in rat basophilic leukemia cells. Lowering the intracellular ATP concentration also released calcium from an intracellular store and made further 45Ca efflux from the cells unresponsive to subsequent antigen stimulation. Antigen-stimulated 45Ca efflux could be restored by the addition of glucose. The ATP-sensitive calcium store appeared to be the same store that releases calcium in response to antigen. In contrast, intracellular ATP was not lowered, and antigen-stimulated secretion was unaffected by mitochondrial inhibitors, provided that glucose was present in the bathing solution. Similarly, antigen-stimulated 45Ca uptake, 45Ca efflux, and the rise in free ionized calcium were unaffected by individual mitochondrial inhibitors in the presence of glucose. However, when the respiratory chain inhibitor antimycin A was used in combination with the ATP synthetase inhibitor oligomycin in the presence of glucose, antigen-stimulated 45Ca uptake was inhibited, whereas the rise in free ionized calcium and secretion were unaffected. Also, antigen-induced depolarization (an indirect measurement of Ca2+ influx across the plasma membrane) was not affected. The inhibition of antigen-stimulated 45Ca uptake could, however, be overcome if a high concentration of the Ca2+ buffer quin2 was present in the cells to buffer the incoming 45Ca. These results suggest that in fully functional rat basophilic leukemia cells the majority of the calcium entering in response to antigen stimulation is initially buffered by a calcium store sensitive to antimycin A and oligomycin, presumably the mitochondria

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

    Indian Academy of Sciences (India)

    For preparing calcium ferrite, calcium tris (maleato) ferrate(III) precursor was prepared by mixing aqueous solutions of iron(III) maleate, calcium maleate and maleic acid. Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to ...

  15. Studies of the calcium metabolism of subjects with renal dysfunction

    International Nuclear Information System (INIS)

    Kotler, L.H.

    1983-01-01

    In order to perform a detailed study of calcium metabolism, it is necessary to differentiate between intestinal absorption and its subsequent behaviour in terms of either uptake onto the bone or excretion. The measurement of calcium absorption involved two separate intakes of the tracer 47 Ca. Each subject ingested a known activity. Measurements on blood samples were made after 5 hours and a smoothed curve describing the appearance of the activity in the plasma was determined. About 4 weeks after oral ingestion a known activity was injected into the subject and the procedure repeated. A curve describing the differential transfer of calcium from the intestine to the blood stream was derived by performing a deconvolution procedure on the two curves

  16. Single channel recording of a mitochondrial calcium uniporter.

    Science.gov (United States)

    Wu, Guangyan; Li, Shunjin; Zong, Guangning; Liu, Xiaofen; Fei, Shuang; Shen, Linda; Guan, Xiangchen; Yang, Xue; Shen, Yuequan

    2018-01-29

    Mitochondrial calcium uniporter (MCU) is the pore-forming subunit of the entire uniporter complex and plays an important role in mitochondrial calcium uptake. However, the single channel recording of MCU remains controversial. Here, we expressed and purified different MCU proteins and then reconstituted them into planar lipid bilayers for single channel recording. We showed that MCU alone from Pyronema omphalodes (pMCU) is active with prominent single channel Ca 2+ currents. In sharp contrast, MCU alone from Homo sapiens (hMCU) is inactive. The essential MCU regulator (EMRE) activates hMCU, and therefore, the complex (hMCU-hEMRE) shows prominent single channel Ca 2+ currents. These single channel currents are sensitive to the specific MCU inhibitor Ruthenium Red. Our results clearly demonstrate that active MCU can conduct large amounts of calcium into the mitochondria. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Effects of thyroid hormones on calcium contents and 45Ca exchange in rat skeletal muscle

    International Nuclear Information System (INIS)

    Everts, M.E.; Clausen, T.

    1986-01-01

    In 4-wk-old rats, pretreatment with L-triiodothyronine (T3) increased calcium content by 100% and the 30-min 45 Ca uptake by 64% in the soleus, whereas the extensor digitorum longus (EDL) muscle showed no significant change. The stimulation of 45 Ca uptake was resistant to dantrolene and methoxyverapamil (D600) and could not be attributed to altered permeability of the plasma membrane to calcium, but appears to reflect increased net accumulation of calcium in intracellular pools. The stimulating effect of high K0 (20 mM) on 45 Ca uptake was more pronounced in soleus than in EDL and could be suppressed by dantrolene and D600. The results indicate that the effects of T3 on calcium content and 45 Ca exchange are primarily exerted on muscles containing a large proportion of slow-twitch, oxidative fibers. In soleus muscle from hyperthyroid rats the stimulating effects of high K0 on 45 Ca uptake and lactate production were, respectively, 3.4 and 4.5 times larger than in those obtained from controls. These observations further support the earlier proposed idea [C. van Hardeveld and T. Clausen. Am. J. Physiol. 247 (Endocrinol. Metab. 10): E421-E430, 1984] that the metabolic effects of thyroid hormone depend on the availability of cellular as well as extracellular calcium

  18. Effects of thyroid hormones on calcium contents and 45Ca exchange in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Everts, M.E.; Clausen, T.

    1986-09-01

    In 4-wk-old rats, pretreatment with L-triiodothyronine (T3) increased calcium content by 100% and the 30-min /sup 45/Ca uptake by 64% in the soleus, whereas the extensor digitorum longus (EDL) muscle showed no significant change. The stimulation of /sup 45/Ca uptake was resistant to dantrolene and methoxyverapamil (D600) and could not be attributed to altered permeability of the plasma membrane to calcium, but appears to reflect increased net accumulation of calcium in intracellular pools. The stimulating effect of high K0 (20 mM) on /sup 45/Ca uptake was more pronounced in soleus than in EDL and could be suppressed by dantrolene and D600. The results indicate that the effects of T3 on calcium content and /sup 45/Ca exchange are primarily exerted on muscles containing a large proportion of slow-twitch, oxidative fibers. In soleus muscle from hyperthyroid rats the stimulating effects of high K0 on /sup 45/Ca uptake and lactate production were, respectively, 3.4 and 4.5 times larger than in those obtained from controls. These observations further support the earlier proposed idea (C. van Hardeveld and T. Clausen. Am. J. Physiol. 247 (Endocrinol. Metab. 10): E421-E430, 1984) that the metabolic effects of thyroid hormone depend on the availability of cellular as well as extracellular calcium.

  19. Effects of ethanol on calcium transport across the liver cell plasma membrane

    International Nuclear Information System (INIS)

    Bernstein, J.; Santacana, G.

    1987-01-01

    The effect of ethanol on calcium transport by the liver cell was studied by using a rat liver slice preparation. Ethanol was shown to decrease by about 30% the rate constant for 45 Ca efflux from the intracellular compartment. This inhibitory effect of ethanol was not observed in the absence of Ca 2+ or Na + from the incubation medium. Ethanol was also shown to greatly increase non-insulin calcium uptake by liver slices. This effect of ethanol appeared to be dose dependent and was not observed in the absence of Na + from the incubation medium. The ability of ethanol to increase calcium uptake by the hepatocyte was completely blocked by 1 mM Amiloride. Amiloride, however, did not affect the increased entry of either Na + or Ca 2+ produced by 10 mM Ouabain, a specific inhibitor of the sodium pump. Carbon tetrachloride (CCl 4 ), a well known hepatotoxin, also increased calcium uptake by the hepatocyte. Amiloride, however, was not able to block the CCl 4 -induced calcium uptake. These results suggest that ethanol activates a Na + entry pathway, probably represented by a Na + /H + exchanger, which in turn stimulates an entry of Ca 2+ through a Na + /Ca 2+ exchange mechanism located in the plasma membrane of the hepatocyte

  20. Children's Bone Health and Calcium

    Science.gov (United States)

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

  1. Calcium – how and why?

    Indian Academy of Sciences (India)

    Unknown

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

  2. Inhibition of calmodulin - regulated calcium pump activity in rat brain by toxaphene

    International Nuclear Information System (INIS)

    Trottman, C.H.; Moorthy, K.S.

    1986-01-01

    In vivo effects of toxaphene on calcium pump activity in rat brain synaptosomes was studied. Male Sprague-Dawley rats were dosed with toxaphene at 0,25,50, and 100 mg/kg/day for 3 days and sacrificed 24 h after last dose. Ca 2+ -ATPase activity and 45 Ca uptake were determined in brain P 2 fraction. Toxaphene inhibited both Ca 2+ -ATPase activity and 45 Ca 2+ uptake and the inhibition was dose dependent. Both substrate and Ca 2+ activation kinetics of Ca 2+ -ATPase indicated non-competitive type of inhibition as evidenced by decreased catalytic velocity but not enzyme-substrate affinity. The inhibited Ca 2+ -ATPase activity and Ca 2+ uptake were restored to normal level by exogenously added calmodulin which increased both velocity and affinity. The inhibition of Ca 2+ -ATPase activity and Ca 2+ uptake and restoration by calmodulin suggests that toxaphene may impair active calcium transport mechanisms by decreasing regulator protein calmodulin levels

  3. 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 500...

  4. Antenatal calcium intake in Malaysia.

    Science.gov (United States)

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

    2014-04-01

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

  5. The Plasma Membrane Calcium Pump

    Science.gov (United States)

    Rasmussen, H.

    1983-01-01

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

  6. Voltage-Gated Calcium Channels

    Science.gov (United States)

    Zamponi, Gerald Werner

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

  7. MICU1 Serves as a Molecular Gatekeeper to Prevent In Vivo Mitochondrial Calcium Overload

    Directory of Open Access Journals (Sweden)

    Julia C. Liu

    2016-08-01

    Full Text Available MICU1 is a component of the mitochondrial calcium uniporter, a multiprotein complex that also includes MICU2, MCU, and EMRE. Here, we describe a mouse model of MICU1 deficiency. MICU1−/− mitochondria demonstrate altered calcium uptake, and deletion of MICU1 results in significant, but not complete, perinatal mortality. Similar to afflicted patients, viable MICU1−/− mice manifest marked ataxia and muscle weakness. Early in life, these animals display a range of biochemical abnormalities, including increased resting mitochondrial calcium levels, altered mitochondrial morphology, and reduced ATP. Older MICU1−/− mice show marked, spontaneous improvement coincident with improved mitochondrial calcium handling and an age-dependent reduction in EMRE expression. Remarkably, deleting one allele of EMRE helps normalize calcium uptake while simultaneously rescuing the high perinatal mortality observed in young MICU1−/− mice. Together, these results demonstrate that MICU1 serves as a molecular gatekeeper preventing calcium overload and suggests that modulating the calcium uniporter could have widespread therapeutic benefits.

  8. Phosphocitrate inhibits mitochondrial and cytosolic accumulation of calcium in kidney cells in vivo.

    Science.gov (United States)

    Tew, W P; Malis, C D; Howard, J E; Lehninger, A L

    1981-01-01

    Synthetic 3-phosphocitrate, an extremely potent inhibitor of calcium phosphate crystallization as determined in a nonbiological physical-chemical assay, has many similarities to a mitochondrial factor that inhibits crystallization of nondiffracting amorphous calcium phosphate. In order to determine whether phosphocitrate can prevent uptake and crystallization of calcium phosphate in mitochondria in vivo, it was administered intraperitoneally to animals given large daily doses of calcium gluconate or parathyroid hormone, a regimen that causes massive accumulation and crystallization of calcium phosphate in the mitochondria and cytosol of renal tubule cells in vivo. Administration of phosphocitrate greatly reduced the net uptake of Ca2+ by the kidneys and prevented the appearance of apatite-like crystalline structures within the mitochondrial matrix and cytosol of renal tubule cells. Phosphocitrate, which is a poor chelator of Ca2+, did not reduce the hypercalcemia induced by either agent. These in vivo observations therefore indicate that phosphocitrate acts primarily at the cellular level to prevent the extensive accumulation of calcium phosphate in kidney cells by inhibiting the mitochondrial accumulation or crystallization of calcium phosphate. Images PMID:6946490

  9. Determination of Uptake and Release of 2,4-Dichlorophenol on the ...

    African Journals Online (AJOL)

    The uptake and release of 2,4-dichlorophenol on Nigerian clay soil was studied by introducing varying concentrations of the chlorophenol in 0.01 M aqueous calcium chloride solution at pH 4.5 into pretreated clay (0.6% OM) samples. The clay soil was treated with hydrogen peroxide followed by varying concentrations of ...

  10. Inhibition of parathyroid hormone release by maitotoxin, a calcium channel activator

    International Nuclear Information System (INIS)

    Fitzpatrick, L.A.; Yasumoto, T.; Aurbach, G.D.

    1989-01-01

    Maitotoxin, a toxin derived from a marine dinoflagellate, is a potent activator of voltage-sensitive calcium channels. To further test the hypothesis that inhibition of PTH secretion by calcium is mediated via a calcium channel we studied the effect of maitotoxin on dispersed bovine parathyroid cells. Maitotoxin inhibited PTH release in a dose-dependent fashion, and inhibition was maximal at 1 ng/ml. Chelation of extracellular calcium by EGTA blocked the inhibition of PTH by maitotoxin. Maitotoxin enhanced the effects of the dihydropyridine calcium channel agonist (+)202-791 and increased the rate of radiocalcium uptake in parathyroid cells. Pertussis toxin, which ADP-ribosylates and inactivates a guanine nucleotide regulatory protein that interacts with calcium channels in the parathyroid cell, did not affect the inhibition of PTH secretion by maitotoxin. Maitotoxin, by its action on calcium channels allows entry of extracellular calcium and inhibits PTH release. Our results suggest that calcium channels are involved in the release of PTH. Inhibition of PTH release by maitotoxin is not sensitive to pertussis toxin, suggesting that maitotoxin may act distal to the site interacting with a guanine nucleotide regulatory protein, or maitotoxin could interact with other ions or second messengers to inhibit PTH release

  11. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non-immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of paramount importance.

  12. Exosomes: Mechanisms of Uptake

    Directory of Open Access Journals (Sweden)

    Kelly J. McKelvey

    2015-07-01

    Full Text Available Exosomes are 30–100 nm microvesicles which contain complex cellular signals of RNA, protein and lipids. Because of this, exosomes are implicated as having limitless therapeutic potential for the treatment of cancer, pregnancy complications, infections, and autoimmune diseases. To date we know a considerable amount about exosome biogenesis and secretion, but there is a paucity of data regarding the uptake of exosomes by immune and non- immune cell types (e.g., cancer cells and the internal signalling pathways by which these exosomes elicit a cellular response. Answering these questions is of para‐ mount importance.

  13. Calcium, essential for health

    Science.gov (United States)

    Martínez de Victoria, Emilio

    2016-07-12

    Calcium (Ca) is the most abundant mineral element in our body. It accounts for about 2% of body weight. The functions of calcium are: a) functions skeletal and b) regulatory functions. Bone consists of a protein matrix that mineralizes mainly with calcium (the most abundant), phosphate and magnesium, for it is essential an adequate dietary intake of Ca, phosphorus and vitamin D. The ionic Ca (Ca2+) is essential to maintain and / or perform different specialized functions of, virtually, all body cells cellular. Because of its important functions Ca2+ must be closely regulated, keeping plasma concentrations within narrow ranges. For this reason there is an accurate response against hypocalcemia or hypercalcemia in which the parathormone, calcitriol, calcitonin and vitamin K are involved. Ca intakes in the Spanish population are low in a significant percentage of the older adult’s population, especially in women. The main source of Ca in the diet is milk and milk derivatives. Green leafy vegetables, fruits and legumes can be important sources of Ca in a Mediterranean dietary pattern. The bioavailability of dietary Ca depends on physiological and dietary factors. Physiological include age, physiological status (gestation and lactation) Ca and vitamin D status and disease. Several studies relate Ca intake in the diet and various diseases, such as osteoporosis, cancer, cardiovascular disease and obesity.

  14. 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...

  15. Molecular mechanisms of glucose uptake in skeletal muscle at rest and in response to exercise

    Directory of Open Access Journals (Sweden)

    Rodrigo Martins Pereira

    2017-05-01

    Full Text Available Abstract Glucose uptake is an important phenomenon for cell homeostasis and for organism health. Under resting conditions, skeletal muscle is dependent on insulin to promote glucose uptake.Insulin, after binding to its membrane receptor, triggers a cascade of intracellular reactions culminating in activation of the glucose transporter 4, GLUT4, among other outcomes.This transporter migrates to the plasma membrane and assists in glucose internalization.However, under special conditions such as physical exercise, alterations in the levels of intracellular molecules such as ATP and calcium actto regulate GLUT4 translocation and glucose uptake in skeletal muscle, regardless of insulinlevels.Regular physical exercise, due to stimulating pathways related to glucose uptake, is an important non-pharmacological intervention for improving glycemic control in obese and diabetic patients. In this mini-review the main mechanisms involved in glucose uptake in skeletal muscle in response to muscle contraction will be investigated.

  16. Thyroid Uptake Measurement System

    International Nuclear Information System (INIS)

    Nguyen Duc Tuan; Nguyen Thi Bao My; Nguyen Van Sy

    2007-01-01

    The NED-UP.M7 is a complete thyroid uptake and analysis system specifically designed for nuclear medicine. Capable of performing a full range of studies this system provides fast, accurate results for Uptake Studies. The heart of the NED-UP.M7 is a microprocessor-controlled 2048 channel Compact Multi-Channel Analyzer, coupled to a 2 inch x 2 inch NaI(Tl) detector with a USB personal computer interface. The system offers simple, straight-forward operation using pre-programmed isotopes, and menudriven prompts to guide the user step by step through each procedure. The pre-programmed radionuclides include I-123, I-125, I-131, Tc-99m and Cs-137. The user-defined radionuclides also allow for isotope identification while the printer provides hard copy printouts for patient and department record keeping. The included software program running on PC (Windows XP-based) is a user friendly program with menudriven and graphic interface for easy controlling the system and managing measurement results of patient on Excel standard form. (author)

  17. Determination of percent calcium carbonate in calcium chromate

    International Nuclear Information System (INIS)

    Middleton, H.W.

    1979-01-01

    The precision, accuracy and reliability of the macro-combustion method is superior to the Knorr alkalimetric method, and it is faster. It also significantly reduces the calcium chromate waste accrual problem. The macro-combustion method has been adopted as the official method for determination of percent calcium carbonate in thermal battery grade anhydrous calcium chromate and percent calcium carbonate in quicklime used in the production of calcium chromate. The apparatus and procedure can be used to measure the percent carbonate in inorganic materials other than calcium chromate. With simple modifications in the basic apparatus and procedure, the percent carbon and hydrogen can be measured in many organic material, including polymers and polymeric formulations. 5 figures, 5 tables

  18. Calcium oxalate stone and gout.

    Science.gov (United States)

    Marickar, Y M Fazil

    2009-12-01

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

  19. Calcium Signaling in Taste Cells

    Science.gov (United States)

    Medler, Kathryn F.

    2014-01-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. PMID:25450977

  20. Isotopic study of the comparative uptake and release of ions by deciduous and permanent dental enamel

    International Nuclear Information System (INIS)

    Tetteh, G.K.

    1975-01-01

    A comparative study of the uptake and release of calcium, orthophosphate, strontium and sodium from decidus and permanent dental enamel has been made using radioactive techniques. The rates of uptake and release of orthophosphate, strontium and sodium were observed to be greater in deciduous than in permanent enamel. However, for calcium, the rate of uptake was observed to be greater in the deciduous than in the permanent enamel but the rate of release was observed to be smaller in the deciduous enamel. These results in conjunction with the findings of Tetteh (1974) suggest that most of the calcification in the early stages of development of dental enamel is by a hetero-ionic exchange. (author) [fr

  1. Isotopic study of the comparative uptake and release of ions by deciduous and permanent dental enamel

    Energy Technology Data Exchange (ETDEWEB)

    Tetteh, G K [Department of Physics, University of Ghana,Legon

    1975-04-01

    A comparative study of the uptake and release of calcium, orthophosphate, strontium and sodium from decidus and permanent dental enamel has been made using radioactive techniques. The rates of uptake and release of orthophosphate, strontium and sodium were observed to be greater in deciduous than in permanent enamel. However, for calcium, the rate of uptake was observed to be greater in the deciduous than in the permanent enamel but the rate of release was observed to be smaller in the deciduous enamel. These results in conjunction with the findings of Tetteh (1974) suggest that most of the calcification in the early stages of development of dental enamel is by a hetero-ionic exchange.

  2. Clinical and experimental analysis of 201thallium uptake of the heart

    International Nuclear Information System (INIS)

    Strauer, B.E.; Buell, U.; Buerger, S.; Klinikum Grosshadern, Muenchen

    1978-01-01

    Studies were carried out in order to determine the factors influencing myocardial 201 Tl uptake. A total of 158 patients was examined with regard to both 201 Tl uptake and the assessment of left ventricular and coronary function. Moreover, 42 animal experiments were performed. The results demonstrate that: 1) 201 Tl uptake in the normal and hypertrophied human heart is linearly correlated with the muscle mass of the left ventricle (LVMM); 2) 201 Tl uptake is enhanced in the inner layer and is decreased in the outer layer of the left ventricular wall. The 201 Tl uptake of the right ventricle is 40% lower in comparison to the left ventricle; 3) the basic correlation between 201 Tl uptake and LVMM is influenced by alterations of both myocardial flow and myocardial oxygen consumption; and 4) inotropic interventions (isoproterenol, calcium, norepinephrine) as well as coronary dilatation (dipyridamole) may considerably augment 201 Tl uptake in accordance with changes in myocardial oxygen consumption and/or myocardial flow. It is concluded that myocardial 201 Tl uptake is determined by multiple factors. The major determinants have been shown to include muscle mass, myocardial flow and myocardial oxygen consumption. The clinical data obtained from patient groups with normal ventricular function, with coronary artery disease, with left ventricular wall motion abnormalities and with different degree of left ventricular hypertrophy are correlated with quantitated myocardial 201 Tl uptake. (orig./MG) [de

  3. Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

    NARCIS (Netherlands)

    Jones, E.M.; Fenton, M.; Meredith, M.P.; Clargo, N.M.; Ossebaar, S.; Ducklow, H.W.; Venables, H.J.; De Baar, H.J.W.

    2017-01-01

    The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium

  4. Can tumor uptake Tc-99m MDP ?

    International Nuclear Information System (INIS)

    Yand Shun, Fang; Yao, Ming; Zeng, Jun; Shi Zhen, Yu; Zhao Lan, Xiang; Dong Qiang, Gang

    2003-01-01

    tumor is higher than other part of tumor. The uptake rate of tumor is higher than non-skeletal tissue unless kidneys. It maybe connected with necrosis or calcification of tumor. Calcium and phosphorus ions were seen frequently in larger tumor. Not only it was caused by fibrous scar and/or surrounding tissues of granuloma but also intra-tumor coagulation and liquefaction necrosis (Au)

  5. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid

    2013-07-01

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

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

    NARCIS (Netherlands)

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

    2003-01-01

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

  7. 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 in...

  8. 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 not...

  9. Effect of an industrial chemical waste on the uptake of cations by green oat

    Directory of Open Access Journals (Sweden)

    HORTENSIA RADULESCU

    2007-06-01

    Full Text Available Calcium carbonate, obtained as a waste in the industrial manufacture of magnesium carbonate and magnesium oxide from dolomites, can be applied in agriculture. The appreciable amounts of calcium and magnesium in this waste, together with impurities such as iron, zinc, manganese, chromium and copper compounds can be useful in soil amendment and plant nutrition. This paper presents preliminary results of the testing of several waste doses on soil, pursuing their effect on the uptake of cations by green oat (Avena sativa L.. The obtained results show an increase in the amount of calcium, magnesium, zinc and copper found in green oat plants, as well as a decrease of the content of iron and manganese with increasing waste dose. These results may be explained by lower absorptions of iron andmanganese because of the antagonistic effect created by high amounts of calcium and magnesium, as well as by the presence of copper and zinc.

  10. Lipopolysaccharide (LPS)-mediated macrophage activation: the role of calcium in the generation of tumoricidal activity

    International Nuclear Information System (INIS)

    Drysdale, B.E.; Shin, H.S.

    1986-01-01

    As the authors reported, calcium ionophore, A23187, activates macrophages (M theta) for tumor cell killing and the activated M theta produce a soluble cytotoxic factor (M theta-CF) that is similar if not identical to tumor necrosis factor. Based on these observations they have investigated whether calcium is involved in the activation mediated by another potent M theta activator, LPS. The authors have shown that A23187 caused uptake of extracellular 45 Ca ++ but LPS did not. They have examined the effect of depleting extracellular calcium by using medium containing no added calcium containing 1.0 mM EGTA. In no case did depletion result in decreased M theta-CF production by the M theta activated with LPS. Measurements using the fluorescent, intracellular calcium indicator, Quin 2 have also been performed. While ionomycin, caused a rapid change in the Quin-2 signal, LPS at a concentration even in excess of that required to activate the M theta caused no change in the signal. When high doses of Quin 2 or another intracellular chelator, 8-(diethylaminol-octyl-3,4,5-trimethoxybenzoate, were used to treat M theta, M theta-CF production decreased and cytotoxic activity was impaired. These data indicate that one or more of the processes involved in M theta-CF production does require calcium, but that activation mediated by LPS occurs without the influx of extracellular calcium or redistribution of intracellular calcium

  11. A Specific Peptide with Calcium-Binding Capacity from Defatted Schizochytrium sp. Protein Hydrolysates and the Molecular Properties.

    Science.gov (United States)

    Cai, Xixi; Yang, Qian; Lin, Jiaping; Fu, Nanyan; Wang, Shaoyun

    2017-03-29

    Marine microorganisms have been proposed as a new kind of protein source. Efforts are needed in order to transform the protein-rich biological wastes left after lipid extraction into value-added bio-products. Thus, the utilization of protein recovered from defatted Schizochytrium sp. by-products presents an opportunity. A specific peptide Tyr-Leu (YL) with calcium-binding capacity was purified from defatted Schizochytrium sp. protein hydrolysates through gel filtration chromatography and RP-HPLC. The calcium-binding activity of YL reached 126.34 ± 3.40 μg/mg. The calcium-binding mechanism was investigated through ultraviolet, fluorescence and infrared spectroscopy. The results showed that calcium ions could form dative bonds with carboxyl oxygen atoms and amino nitrogen atoms as well as the nitrogen and oxygen atoms of amide bonds. YL-Ca exhibited excellent thermal stability and solubility, which was beneficial for its absorption and transport in the basic intestinal tract of the human body. Moreover, the cellular uptake of calcium in Caco-2 cells showed that YL-Ca could enhance calcium uptake efficiency and protect calcium ions against precipitation caused by dietary inhibitors such as tannic acid, oxalate, phytate and metal ions. The findings indicate that the by-product of Schizochytrium sp. is a promising source for making peptide-calcium bio-products as algae-based functional supplements for human beings.

  12. A Specific Peptide with Calcium-Binding Capacity from Defatted Schizochytrium sp. Protein Hydrolysates and the Molecular Properties

    Directory of Open Access Journals (Sweden)

    Xixi Cai

    2017-03-01

    Full Text Available Marine microorganisms have been proposed as a new kind of protein source. Efforts are needed in order to transform the protein-rich biological wastes left after lipid extraction into value-added bio-products. Thus, the utilization of protein recovered from defatted Schizochytrium sp. by-products presents an opportunity. A specific peptide Tyr-Leu (YL with calcium-binding capacity was purified from defatted Schizochytrium sp. protein hydrolysates through gel filtration chromatography and RP-HPLC. The calcium-binding activity of YL reached 126.34 ± 3.40 μg/mg. The calcium-binding mechanism was investigated through ultraviolet, fluorescence and infrared spectroscopy. The results showed that calcium ions could form dative bonds with carboxyl oxygen atoms and amino nitrogen atoms as well as the nitrogen and oxygen atoms of amide bonds. YL-Ca exhibited excellent thermal stability and solubility, which was beneficial for its absorption and transport in the basic intestinal tract of the human body. Moreover, the cellular uptake of calcium in Caco-2 cells showed that YL-Ca could enhance calcium uptake efficiency and protect calcium ions against precipitation caused by dietary inhibitors such as tannic acid, oxalate, phytate and metal ions. The findings indicate that the by-product of Schizochytrium sp. is a promising source for making peptide-calcium bio-products as algae-based functional supplements for human beings.

  13. Radioiodine uptake measurements in thyroid

    International Nuclear Information System (INIS)

    Kadireshn, A.; Kapur, S.C.; Samuel, J.R.; Mahajan, M.K.

    1988-01-01

    Evaluation of thyroid function can be carried out by measuring the uptake of orally administered radioactive iodine. The results of the thyroid uptake measurements for the period 1982-1987 in Christian Medical College, Ludhiana are presented here. About 3000 patients were screened during the analysis period. (author)

  14. Aquaporins and root water uptake

    Science.gov (United States)

    Water is one of the most critical resources limiting plant growth and crop productivity, and root water uptake is an important aspect of plant physiology governing plant water use and stress tolerance. Pathways of root water uptake are complex and are affected by root structure and physiological res...

  15. Uptake of nuclides by plants

    International Nuclear Information System (INIS)

    Greger, Maria

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate

  16. Uptake of nuclides by plants

    Energy Technology Data Exchange (ETDEWEB)

    Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

    2004-04-01

    This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate.

  17. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

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

    OpenAIRE

    McDonald, Catherine M.

    1980-01-01

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

  19. [Changes induced by hypertonic solutions in the transportation of calcium by the cardiac reticular sarcoplasma].

    Science.gov (United States)

    Sierra, M; Holguín, J A

    1979-01-01

    In the sarcoplasmic reticulum of the myocardium, celular organell which function is to regulate the cytoplasmic concentration of calcium in contraction and relaxation, we have studied the effect of hypertonic solutions of sucrose between 1 and 6.96 times the normal tonicity in order to observe the behavior of the internal linked or free calcium of this structure, as well as to prove the hypothesis that hypertonic solutions encourage the calcium exit of the sarcoplasmatic reticulum with the resulting signs of contractures. The following results were obtained: 1. The ATP hydrolisis and calcium transport rate are 14% and 90% respectively of the maximum speeds of 10(-5) M in calcium, while for concentrations of 10(-7) M or ess of the said cation, the transport rates and the ATPase do not reach 5% of the maximum values. 2. Between 1 and 2.54 times of the normal tonicity the calcium uptake remains between 400 and 500 nmoles of calcium/mg protein/min, the transported amount of calcium varies between 14 and 16 nmoles/mg protein and the rate of the ATP hydrolysis increases a 37% to 0.4 M in sucrose. 3. Between 0.4 and 1.2 M in sucrose of 2.54 to 6.96 times the isotonicity, the calcium transport rate velocity as well as the ATP hydrolisis are strongly inhibited. The vesicles volume minimizes and the amount of linked calcium remains within the control values, proving that the capacity of linking this cathion is independent from sarcoplasmic reticulum volume. These results show that the sarcoplasmic reticulum is involved in the contractures induced by hypertonic solutions in intact cells, since the osmolarity increase produces changes of volume which results in a decrease of the calcium transportation velocity or in an increase of the exit of said cathion.

  20. Effect of ouabain, digoxin and digitoxigenin on potassium uptake and histamine release from rat peritoneal mast cells

    DEFF Research Database (Denmark)

    Knudsen, T; Ferjan, I; Johansen, Torben

    1993-01-01

    Rat peritoneal mast cells were used to study the effects of digitalis glycosides on potassium uptake and histamine release induced by compound 48/80, substance P and egg-albumin (immunological release). In the absence of calcium all glycosides inhibited potassium uptake. Ouabain and digoxin....... Hydrophilic digitalis glycosides seem to enhance histamine release secondary to an increase in intracellular sodium. Lipophilic glycosides have no effect on the release....

  1. Integumentary L-histidine transport in a euryhaline polychaete worm: regulatory roles of calcium and cadmium in the transport event.

    Science.gov (United States)

    Ahearn, H R; Ahearn, G A; Gomme, J

    2000-09-01

    Integumentary uptake of L-[(3)H]histidine by polychaete worms (Nereis succinea) from estuarine waters of Oahu, Hawaii was measured in the presence and absence of calcium and cadmium using a physiological saline that approximated the ion composition of 60 % sea water. In this medium 1 micromol L(-1) cadmium significantly increased (Psystem carrier protein that is regulated by the external divalent cations calcium and cadmium.

  2. 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 ...

  3. Calcium Supplements: Do Men Need Them Too?

    Science.gov (United States)

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

  4. Cadmium uptake by plants

    Energy Technology Data Exchange (ETDEWEB)

    Haghiri, F.

    1973-01-01

    Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

  5. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Sabatini, S.; Kurtzman, N.A.

    1987-01-01

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

  6. Calcium chromate process related investigations

    International Nuclear Information System (INIS)

    Dillard, B.M.

    1979-01-01

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

  7. Effects of calcium and magnesium acetates on tissue distribution of carcinogenic doses of calcium chloride in Wistar rats

    International Nuclear Information System (INIS)

    Kasprzak, K.S.; Poirier, L.A.

    1985-01-01

    Previous studies have shown that magnesium, unlike calcium, prevents cadmium carcinogenesis at the subcutaneous injection site, and that neither magnesium nor calcium has any significant influence on the production of testicular tumors by cadmium in rats. The present investigation attempts to disclose the nature of those different effects by comparing the results of administration of both physiological metals on the uptake and distribution of carcinogenic doses of cadmium in rats. Male Wistar rats received a single subcutaneous (s.c.) injection of 109 CdCl 2 (0.02 mmol/kg or 0.04 mmol/kg) and s.c. injections (one daily) of calcium acetate (CaAcet; 0.16 mmol/kg), or magnesium acetate (MgAcet; 4 mmol/kg) or saline on the day before, the day of and the day after the 109 CdCl 2 dosing. The concentration of cadmium in tissues was determined by gamma-counting on the 4th, the 15th and the 45th day after 109 CdCl 2 injection. The concentration of cadmium in tissues on day 4 was ranked as follows: liver > kidney > the injection site skin > pancreas > spleen > heart > lung > distant skin > testes > blood. Administration of CaAcet increased by over 20% and that of MgAcet decreased by over 30% the initial uptake of both cadmium doses at the injection site. The MgAcet may prevent cadmium carcinogenesis by inhiniting the uptake of cadmium by the injection site tissues. In the testis and in all other tissues investigated, except kidney, the effects of the physiological metals were reversed, CaAcet and MgAcet tended to increase the uptake of cadmium. CaAcet exerted no noticeable effects on the uptake of cadmium by the kidney. The observed results of CaAcet and MgAcet administration on the concentration of cadmium in distal tissues seem to depend on the alterations in cadmium uptake at the injection site. (author)

  8. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  9. Effects of gastrin on calcium homeostasis in chickens

    International Nuclear Information System (INIS)

    Persson, P.; Gagnemo-Persson, R.; Orberg, J.; Chen, D.; Hakanson, R.

    1991-01-01

    As in the rat, gastrin and an extract of the acid-producing part of the stomach (proventriculus) were found to lower the blood Ca2+ concentration in the chicken. Furthermore, gastrin enhanced the uptake of 45Ca into the femur. It has been suggested previously that gastrin causes hypocalcemia in the rat by releasing gastrocalcin, a hypothetical hormone thought to reside in the acid-producing part of the stomach. The results of the present study in the chicken are in agreement with this concept. Not only exogenous, but also endogenous gastrin lowered blood calcium levels. Thus, the serum gastrin concentration was increased in response to ranitidine-evoked blockade of the gastric acid output; the rise in gastrin was associated with a transient drop in blood calcium. Also, food intake produced a rise in the serum gastrin concentration and a transient drop in blood calcium. However, injection of ranitidine or food intake in proventriclectomized (acid-producing part of the stomach extirpated) chickens failed to lower blood calcium, supporting the view that the gastrin-evoked hypocalcemia depends upon an agent in the gastric (proventriculus) mucosa. The authors suggest that endogenous and exogenous gastrin evoke hypocalcemia in the chicken by the same mechanism as that which has been postulated in the rat, i.e. by mobilization of the candidate hormone gastrocalcin from endocrine cells in the acid-producing gastric mucosa

  10. Uptake and loss of dissolved zinc by the stickleback gasterosteus Aculeatus l. [Zinc 65

    Energy Technology Data Exchange (ETDEWEB)

    Matthiessen, P.; Brafield, A.E.

    1977-01-01

    Uptake and loss by sticklebacks of both stable zinc and /sup 65/Zn in hard and soft water were studied for periods up to 400 h. In calcium-free water, the zinc uptake curve is approximately asymptotic over a period of 24 h, while in hard water internal Zn levels dropped at 24 h. Over 5 h, fish in hard tapwater absorb about 3 to 5 times more Zn than those in calcium-free water. There is positive linear correlation between log Zn uptake and log wet weight of fish. Whole-body concentration factors (c.f.) at 16 h reach a maximum of 12.2 (mean = 2.9), highest concentrations of Zn being found in the gills (mean c.f. = 5.1), and lowest concentrations in the gonads (mean c.f. = 0.8). Over longer periods (400 h), internal stable zinc levels of fish exposed to 1 and 4 ppM Zn/sup +2/ remain little higher than controls (max. 28%) /sup 65/Zn efflux in zinc-free water falls to zero after 5 h, more zinc (78%) being lost after uptake in tapwater than in calcium-free water (56%).

  11. Relation between the location of elements in the periodic table and tumor-uptake rate.

    Science.gov (United States)

    Ando, A; Ando, I; Hiraki, T; Hisada, K

    1985-01-01

    The bipositive ions and anions, with few exceptions, indicated a low tumor uptake rate. On the other hand, compounds of Hg, Au and Bi, which have a strong binding power to protein, showed a high tumor uptake rate. As Hg2+, Au+ and Bi3+ are soft acids according to the classification of Lewis acids, it was thought that these ions would bind strongly to soft bases (R-SH, R-S-) present in tumor tissue. For many hard acids such as 85Sr2+, 67Ga3+, 181Hf4+, and 95Nb5+, tumor uptake rates are shown as a function of ionic potentials (valency/ionic radii) of the metal ions. Considering the present data and previously reported results, it was presumed that hard acids of trivalence, quadrivalence and pentavalence would replace calcium in the calcium salts of hard bases (calcium salts of acid mucopolysaccharides, etc.). Ionic potentials of alkaline metals and Tl were small, but the tumor-uptake rate of these elements indicated various values. As Ge and Sb are bound by covalent bonds to chloride, GeCl4 and SbCl3 behaved differently from many metallic compounds in tumor tissue.

  12. Inhibitory effect of calcium channel blockers on proliferation of human glioma cells in vitro

    International Nuclear Information System (INIS)

    Kunert-Radek, J.; Stepien, H.; Lyson, K.; Pawlikowski, M.; Radek, A.

    1989-01-01

    The effects of 2 specific calcium channel blockers, verapamil and nimodipine, on the proliferation of human glioma tumour cells were investigated in vitro. Tumour tissues for primary cell cultures were obtained bioptically from 3 patients with the histopathological diagnosis of glioblastoma. The [ 3 H]-thymidine incorporation into glioma tumour cells DNA was used as a sensitive index of the cell proliferation. It was found that varapamil (10 4 -10 5 M) and nimodipine (10 4 -10 6 M) significantly inhibited the [ 3 H]-thymidine uptake in a dose-related manner. The inhibitory effect of both calcium channel antagonists was reversed by stimultancous addition of calcium chloride (5x10 3 M). These results indicate that verapamil and nimodipine may exert an antiproliferative effect on glioma cells growth acting through a blokade of specific voltage-dependent calcium channels. (author)

  13. p32, a novel binding partner of Mcl-1, positively regulates mitochondrial Ca{sup 2+} uptake and apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Kang [Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Wang, Yinyin; Chang, Zhijie [School of Medicine, Tsinghua University, Beijing (China); Lao, Yuanzhi, E-mail: laurence_ylao@163.com [School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai (China); Chang, Donald C., E-mail: bochang@ust.hk [Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2014-08-22

    Highlights: • p32 binds to Mcl-1. • p32 affects apoptosis. • p32 and Mcl-1 regulate mitochondrial Ca{sup 2+}. - Abstract: Mcl-1 is a major anti-apoptotic Bcl-2 family protein. It is well known that Mcl-1 can interact with certain pro-apoptotic Bcl-2 family proteins in normal cells to neutralize their pro-apoptotic functions, thus prevent apoptosis. In addition, it was recently found that Mcl-1 can also inhibit mitochondrial calcium uptake. The detailed mechanism, however, is still not clear. Based on Yeast Two-Hybrid screening and co-immunoprecipitation, we identified a mitochondrial protein p32 (C1qbp) as a novel binding partner of Mcl-1. We found that p32 had a number of interesting properties: (1) p32 can positively regulate UV-induced apoptosis in HeLa cells. (2) Over-expressing p32 could significantly promote mitochondrial calcium uptake, while silencing p32 by siRNA suppressed it. (3) In p32 knockdown cells, Ruthenium Red treatment (an inhibitor of mitochondrial calcium uniporter) showed no further suppressive effect on mitochondrial calcium uptake. In addition, in Ruthenium Red treated cells, Mcl-1 also failed to suppress mitochondrial calcium uptake. Taken together, our findings suggest that p32 is part of the putative mitochondrial uniporter that facilitates mitochondrial calcium uptake. By binding to p32, Mcl-1 can interfere with the uniporter function, thus inhibit the mitochondrial Ca{sup 2+} uploading. This may provide a novel mechanism to explain the anti-apoptotic function of Mcl-1.

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

    Directory of Open Access Journals (Sweden)

    Borje E. Christopher Nordin

    2010-09-01

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

  15. Ca uptake and its influence by growth hormone in osteoblasts of fetal rat calvaria

    International Nuclear Information System (INIS)

    Wang Hongfu; Jin Weifang; Sekimoto Haku

    1994-01-01

    Uptake and release of Ca 2+ are important functions of osteoblasts. In the paper we studied the uptake of calcium and influence by Growth Hormone in osteoblasts of fetal rat calvaria by liquid scintillation spectrometry of 45 Ca 2+ . In short-term cultures of the bone derived cells, the uptake of 45 Ca 2+ increased steadily. The activity of 45 Ca 2+ in the cells of 15 minute cultures was 2∼3 times of that in the 0 minute cultures. It continued to increase in the cells of 30 minute cultures. Exposure of the bone cells to GH at 55.3 ng/ml increased the uptake of 45 Ca 2+ by 2.3 times in the 30 minute cultures and 1.5 times in the 60 minute cultures than those of the control

  16. Uptake by Plants of Radiostrontium from Contaminated Soils

    DEFF Research Database (Denmark)

    Andersen, A. J.

    1965-01-01

    In a recent report from this department it was shown that the extractability of radiostrontium from contaminated soil samples was effectively reduced by heat treatment and by the addition of phosphate to the soil. It was pointed out that, under emergency conditions, heat-treatment of the contamin......In a recent report from this department it was shown that the extractability of radiostrontium from contaminated soil samples was effectively reduced by heat treatment and by the addition of phosphate to the soil. It was pointed out that, under emergency conditions, heat......-treatment of the contaminated soil surface and heavy phosphate application might thus reduce the uptake by plants of radiostrontium more efficiently than liming, which is only effective in soils of low calcium status. In the investigation reviewed here the influence of heat treatment and superphosphate application on the plant...... uptake of radiostrontium was examined in pot experiments. For comparison the effect of applying calcium carbonate to the contaminated soil surface was also determined....

  17. Technetium uptake by Sinapis Alba

    International Nuclear Information System (INIS)

    Mueller, H.; Ter Meer-Bekk, Ch.

    1986-01-01

    Transfer factors for pertechnetate uptake was determined for Sinapis Alba cultured hydroponically. For the freshly harvested, undried plants transfer factors were found between 13 and 40 depending on the growth period. (author)

  18. Calcium and Calcium Supplements: Achieving the Right Balance

    Science.gov (United States)

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

  19. The mode of inhibition of the Na+-K+ pump activity in mast cells by calcium

    DEFF Research Database (Denmark)

    Knudsen, T; Johansen, Torben

    1989-01-01

    , and hence the pump activity. This hypothesis is supported by the stimulation of pump activity produced by monensin, which is not inhibited by calcium. The enhancement of pump activity after exposure of calcium-deprived cells to EGTA might be the result of a further increase in the sodium permeability......1 The inhibition by calcium of the Na(+)-K+ pump in the plasma membrane of rat peritoneal mast cells was studied in pure populations of the cells by measuring the ouabain-sensitive uptake of the radioactive potassium analogue, 86rubidium (86Rb+). 2 Exposure of the cells to calcium induced a time......- and concentration-dependent decrease in the ouabain-sensitive K+(86Rb+)-uptake of the cells without influencing the ouabain-resistant uptake. The development of the inhibition required the presence of potassium in the medium in the millimolar range (1.5-8.0 mM), and it did not occur at a concentration of potassium...

  20. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

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

  1. Comparative aspects of calcium dynamics in calcified tissues in the goldfish Carassius auratus

    International Nuclear Information System (INIS)

    Ichii, Taro; Mugiya, Yasuo

    1983-01-01

    The comparative nature of calcium physiology in bone, scales and otoliths was studied in young goldfish, Carassius auratus. Net calcium uptake by the fish was estimated to be 143 μg/g body weight/day. Of that, 79 % was distributed in bone, 13 % in scales, 3.5 % in otoliths and 4.5 % in soft tissues. Scales showed the highest incorporation of 45 Ca per mg-tissue weight after 1 or 2 days in 45 Ca-containing water; bone came second and otoliths last. However, 35 days after transfer to non-radioactive water, the order of descending radioactivity had changed to otoliths, bone and scales, reflecting different rates of calcium turnover. In bone, prelabeled 45 Ca activity increased for the first 2 days after transfer and then decreased gradually (biological half-life, Tsub(0.5) = 94 days). In otoliths, prelabeled radioactivity consistently increased for 35 days. Scales showed two phases of calcium turnover. They lost about 33 % of their prelabeled radioactivity during the first 7 days (Tsub(0.5) = 10.5 days) in non-radioactive water, but thereafter the rate of decrease slowed down greatly (Tsub(0.5) = 210 days). These two phases of calcium turnover were found in the osseous layer (including calcium crystals in the fibrillary plate) of scales, indicating the presence of physiologically labile as well as stable forms of calcium in the layer. (author)

  2. Controlled adsorption and release onto calcium phosphates materials and drug delivery applications

    Directory of Open Access Journals (Sweden)

    Barroug A.

    2013-11-01

    Full Text Available The adsorptive properties of synthetic calcium phosphates analogous to bone mineral were examined with respect to cisplatin and risedronate, two biological active drugs; the uptake and release experiments were carried out under various conditions in order to understand the basic mechanism of interaction. The effect of temperature and solution composition were highlighted and discussed. The adsorption results obtained for the therapeutic agents demonstrated that, depending on the conditions investigated (nature of the sorbent, concentration range, ionic composition, temperature…, the shape of the isotherms is of Freundlich or Langmuir type. The adsorption is described as an ion-exchange process in dilute solutions, while the interaction appears to be reactive for concentrated solutions (dissolution of mineral ions from the apatite substrate and formation of soluble calcium complex and/or precipitation of calcium salts involving sorbate molecules. The information gained on the surface reactivity of calcium phosphate were exploited to associate an antibiotic to calcium phosphate cements for drug delivery applications. The specimens were obtained by combination of calcium phosphate and calcium carbonate powders upon mixing with water. The physicochemical properties of the paste were altered by the drug loading method (in the liquid or solid phase. Thus, a dose-dependent effect was noticed for the paste setting time, hardening and the release process.

  3. Comparative aspects of calcium dynamics in calcified tissues in the goldfish Carassius auratus

    Energy Technology Data Exchange (ETDEWEB)

    Ichii, Taro; Mugiya, Yasuo (Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries)

    1983-07-01

    The comparative nature of calcium physiology in bone, scales and otoliths was studied in young goldfish, Carassius auratus. Net calcium uptake by the fish was estimated to be 143 ..mu..g/g body weight/day. Of that, 79 % was distributed in bone, 13 % in scales, 3.5 % in otoliths and 4.5 % in soft tissues. Scales showed the highest incorporation of /sup 45/Ca per mg-tissue weight after 1 or 2 days in /sup 45/Ca-containing water; bone came second and otoliths last. However, 35 days after transfer to non-radioactive water, the order of descending radioactivity had changed to otoliths, bone and scales, reflecting different rates of calcium turnover. In bone, prelabeled /sup 45/Ca activity increased for the first 2 days after transfer and then decreased gradually (biological half-life, Tsub(0.5) = 94 days). In otoliths, prelabeled radioactivity consistently increased for 35 days. Scales showed two phases of calcium turnover. They lost about 33 % of their prelabeled radioactivity during the first 7 days (Tsub(0.5) = 10.5 days) in non-radioactive water, but thereafter the rate of decrease slowed down greatly (Tsub(0.5) = 210 days). These two phases of calcium turnover were found in the osseous layer (including calcium crystals in the fibrillary plate) of scales, indicating the presence of physiologically labile as well as stable forms of calcium in the layer.

  4. Why Calcium? How Calcium Became the Best Communicator*

    OpenAIRE

    Carafoli, Ernesto; Krebs, Joachim

    2016-01-01

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

  5. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    Christensen, Hilbert

    1962-12-01

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

  6. Influence of dietary calcium on bone calcium utilization

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  7. REAL INTAKE AND PROVISION WITH VITAMINS AND CALCIUM IN OSTEOPOROSIS: ASSESSMENT BY MEASURING INTAKE AND PLASMA CONCENTRATIONS

    Directory of Open Access Journals (Sweden)

    V. N. Khodyrev

    2014-01-01

    Full Text Available Aim:  To assess the providing an organism with vitamins (А, В2, С, Е, β-carotene, and calcium in osteoporosis patients by measuring their intake and plasma concentrations. Materials and methods: 108 pairs “osteoporosis patient – healthy volunteer” aged 64.29±9.73 years were formed using a “case-control” method. Real intake of vitamins and calcium was studied defining the frequency of food taking for a month using questionnaire method. Daily intake of vitamins А, В2, С, Е, β-carotene, and calcium was calculated based on the analysis of the frequency of food taking. Among the basic group, using randomized method, 60% of osteoporosis patients were selected who underwent definition of plasma levels of vitamins А, В2, С, and Е. The same study was performed in 60 control volunteers. Results: Correlation of the intake of vitamins A, C, and β-carotene with their plasma levels wasn’t noted. It may reveal an increased need in these nutrients in osteoporosis. According to the calcium intake, every osteoporosis patient can be attributed to a population category with deep insufficiency of calcium intake (less than 500 mg a day. Conclusion: The data obtained need further investigation and, first of all, in clinical and biochemical fields (enzymatic non-provision for calcium uptake, clinical manifestations of insufficient provision with nutrients. Solution of these problems would enable regulation of food intake concerning calcium uptake in osteoporosis.

  8. Diselenolane-mediated cellular uptake.

    Science.gov (United States)

    Chuard, Nicolas; Poblador-Bahamonde, Amalia I; Zong, Lili; Bartolami, Eline; Hildebrandt, Jana; Weigand, Wolfgang; Sakai, Naomi; Matile, Stefan

    2018-02-21

    The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

  9. Effect of calcium on the salt tolerance of different wheat (triticum aestivum l.) genotypes

    International Nuclear Information System (INIS)

    Arshad, M.; Saqib, M.; Akhtar, J.

    2012-01-01

    In saline soil conditions the availability and uptake of Ca/sup 2+/ is reduced that results in the loss of membrane integrity and other disorders associated with Ca/sup 2+/ deficiency in plants. A wheat genotype efficient in uptake and utilization of calcium under saline conditions may be better able to withstand saline conditions in the field. Very little information is available on wheat response to salinity and low Ca/sup 2+/ as screening of wheat genotypes has usually been done against salinity alone. The present study was designed to evaluate the performance of different wheat genotypes against salinity at low and adequate calcium supply. The experiment was conducted in hydroponics with four treatments including T1: non-saline with adequate Ca/sup 2+/, T2: non-saline with low Ca/sup 2+/ (level of calcium was 1/4 of the adequate level), T3: saline (125 mM NaCl) with adequate Ca/sup 2+/ and T4: saline with low calcium. All the physical growth parameters including shoot length, root length, and shoot and root fresh weights were decreased significantly due to salinity and low calcium alone as well as in combination. Reduction was more pronounced under the combined stress of salinity and low calcium and different genotypes differed significantly in different stress treatments for shoot and root fresh weight production. In saline treatment (T3), the genotypes 25-SAWSN-39 and 25-SAWSN-31 showed better growth performance and accumulated lower Na+ and higher Ca/sup 2+/ where as the genotypes 25-SAWSN-35 and 25-SAWSN-47 showed less growth and had less accumulation of Ca/sup 2+/ and high accumulation of Na+. In salinity + low calcium treatment the genotype 25-SAWSN-39 behaved as a tolerant genotype where as 25-SAWSN-31 behaved similar to the sensitive genotype and these differences were due to high accumulation of Ca/sup 2+/ in 25-SAWSN-39 and vice versa. This study shows that the salt tolerance of wheat genotypes differs with the availability and accumulation of calcium

  10. One Dimensional Finite Element Method Approach to Study Effect of Ryanodine Receptor and Serca Pump on Calcium Distribution in Oocytes

    Science.gov (United States)

    Naik, Parvaiz Ahmad; Pardasani, Kamal Raj

    2013-11-01

    Oocyte is a female gametocyte or germ cell involved in reproduction. Calcium ions (Ca2+) impact nearly all aspects of cellular life as they play an important role in a variety of cellular functions. Calcium ions contributes to egg activation upon fertilization. Since it is the internal stores which provide most of the calcium signal, much attention has been focused on the intracellular channels. There are mainly two types of calcium channels which release calcium from the internal stores to the cytoplasm in many cell types. These channels are IP3-Receptor and Ryanodine Receptor (RyR). Further it is essential to maintain low cytosolic calcium concentration, the cell engages the Serco/Endoplasmic reticulum Ca2+ ATPases (SERCA) present on the ER or SR membrane for the re-uptake of cytosolic calcium at the expense of ATP hydrolysis. In view of above an attempt has been made to study the effect of the Ryanodine receptor (RyR) and the SERCA pump on the calcium distribution in oocytes. The main aim of this paper is to study the calcium concentration in absence and presence of these parameters. The FEM is used to solve the proposed Mathematical model under appreciate initial and boundary conditions. The program has been developed in MATLAB 7.10 for the entire problem to get numerical results.

  11. Regulation of calcium release from the endoplasmic reticulum by the serine hydrolase ABHD2.

    Science.gov (United States)

    Yun, Bogeon; Lee, HeeJung; Powell, Roger; Reisdorph, Nichole; Ewing, Heather; Gelb, Michael H; Hsu, Ku-Lung; Cravatt, Benjamin F; Leslie, Christina C

    2017-09-02

    The serine hydrolase inhibitors pyrrophenone and KT195 inhibit cell death induced by A23187 and H 2 O 2 by blocking the release of calcium from the endoplasmic reticulum and mitochondrial calcium uptake. The effect of pyrrophenone and KT195 on these processes is not due to inhibition of their known targets, cytosolic phospholipase A 2 and α/β-hydrolase domain-containing (ABHD) 6, respectively, but represent off-target effects. To identify targets of KT195, fibroblasts were treated with KT195-alkyne to covalently label protein targets followed by click chemistry with biotin azide, enrichment on streptavidin beads and tryptic peptide analysis by mass spectrometry. Although several serine hydrolases were identified, α/β-hydrolase domain-containing 2 (ABHD2) was the only target in which both KT195 and pyrrophenone competed for binding to KT195-alkyne. ABHD2 is a serine hydrolase with a predicted transmembrane domain consistent with its pull-down from the membrane proteome. Subcellular fractionation showed localization of ABHD2 to the endoplasmic reticulum but not to mitochondria or mitochondrial-associated membranes. Knockdown of ABHD2 with shRNA attenuated calcium release from the endoplasmic reticulum, mitochondrial calcium uptake and cell death in fibroblasts stimulated with A23187. The results describe a novel mechanism for regulating calcium transfer from the endoplasmic reticulum to mitochondria that involves the serine hydrolase ABHD2. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Study on the Effect of Calcium and Potassium Spray on Date Bunch Fading Disorder

    Directory of Open Access Journals (Sweden)

    Hosein Shekofteh

    2017-09-01

    weight, fruit length, fruit diameter, stone weight, stone diameter, and bunch fading percentage at 1℅ level. The highest wet fruit weight, fruit length, fruit diameter, stone weight, and stone diameter were attained in the treatment containing combined application of calcium nitrate and potassium sulfate. Furthermore, the lowest amounts of these traits were obtained in control. The lowest and highest percentage of date bunch fading belonged to the combined treatment of calcium nitrate and potassium sulfate, and control, respectively. In general, application of calcium nitrate and potassium sulfate with each other improved fruit traits and reduced bunch fading percentage. Calcium mobility in the plant takes place mainly in the xylem, together with water. Therefore, calcium uptake is directly related to plant transpiration rate. Conditions of high humidity, cold and low transpiration rates may result in calcium deficiency. Salinity might also cause calcium deficiency because it decreases water uptake by the plant. Since calcium mobility in plants is limited, calcium deficiency appears in younger leaves and in fruits, because they have a very low transpiration rate. Therefore, it is necessary to have a constant supply of calcium for continued growth. Calcium deficiency is usually caused by low calcium availability or water stress which results in low transpiration rates. Calcium is an essential plant nutrient with many roles including participation in metabolic processes of other nutrients uptake, promotion of proper plant cell elongation, and improvement of cell wall structure – calcium is an essential part of plant cell wall. It forms calcium pectate compounds which give stability to cell walls and bind cells together. It also helps protecting the plant against heat stress - calcium improves stomata function and participates in induction of heat shock proteins. In addition, it helps protecting the plant against diseases - numerous fungi and bacteria secret enzymes

  13. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  14. A Crash Course in Calcium Channels.

    Science.gov (United States)

    Zamponi, Gerald W

    2017-12-20

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

  15. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping

    2009-01-01

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

  16. Calcium phosphates for biomedical applications

    Directory of Open Access Journals (Sweden)

    Maria Canillas

    2017-05-01

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

  17. Functions of vitamin D / Calcium

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Excitation-contraction coupling,. Cardiac functions. Hormonal secretion. Control of enzymatic reactions. Mitotic division. Maintenance of cell integrity. Ciliary motility. Notes: Calcium is a vital second messenger.

  18. Calcium signals in planetary embryos

    Science.gov (United States)

    Morbidelli, Alessandro

    2018-03-01

    The calcium-isotope composition of planetary bodies in the inner Solar System correlates with the masses of such objects. This finding could have implications for our understanding of how the Solar System formed.

  19. Calcium homeostasis in diabetes mellitus.

    Science.gov (United States)

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

    2017-09-30

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

  20. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

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

  1. Calcium signaling in liver.

    Science.gov (United States)

    Gaspers, Lawrence D; Thomas, Andrew P

    2005-01-01

    In hepatocytes, hormones linked to the formation of the second messenger inositol 1,4,5-trisphosphate (InsP3) evoke transient increases or spikes in cytosolic free calcium ([Ca2+]i), that increase in frequency with the agonist concentration. These oscillatory Ca2+ signals are thought to transmit the information encoded in the extracellular stimulus to down-stream Ca2+-sensitive metabolic processes. We have utilized both confocal and wide field fluorescence microscopy techniques to study the InsP3-dependent signaling pathway at the cellular and subcellular levels in the intact perfused liver. Typically InsP3-dependent [Ca2+]i spikes manifest as Ca2+ waves that propagate throughout the entire cytoplasm and nucleus, and in the intact liver these [Ca2+]i increases are conveyed through gap junctions to encompass entire lobular units. The translobular movement of Ca2+ provides a means to coordinate the function of metabolic zones of the lobule and thus, liver function. In this article, we describe the characteristics of agonist-evoked [Ca2+]i signals in the liver and discuss possible mechanisms to explain the propagation of intercellular Ca2+ waves in the intact organ.

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

    International Nuclear Information System (INIS)

    Goulding, A.; Cameron, V.

    1978-01-01

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

  3. m-AAA proteases, mitochondrial calcium homeostasis and neurodegeneration.

    Science.gov (United States)

    Patron, Maria; Sprenger, Hans-Georg; Langer, Thomas

    2018-03-01

    The function of mitochondria depends on ubiquitously expressed and evolutionary conserved m-AAA proteases in the inner membrane. These ATP-dependent peptidases form hexameric complexes built up of homologous subunits. AFG3L2 subunits assemble either into homo-oligomeric isoenzymes or with SPG7 (paraplegin) subunits into hetero-oligomeric proteolytic complexes. Mutations in AFG3L2 are associated with dominant spinocerebellar ataxia (SCA28) characterized by the loss of Purkinje cells, whereas mutations in SPG7 cause a recessive form of hereditary spastic paraplegia (HSP7) with motor neurons of the cortico-spinal tract being predominantly affected. Pleiotropic functions have been assigned to m-AAA proteases, which act as quality control and regulatory enzymes in mitochondria. Loss of m-AAA proteases affects mitochondrial protein synthesis and respiration and leads to mitochondrial fragmentation and deficiencies in the axonal transport of mitochondria. Moreover m-AAA proteases regulate the assembly of the mitochondrial calcium uniporter (MCU) complex. Impaired degradation of the MCU subunit EMRE in AFG3L2-deficient mitochondria results in the formation of deregulated MCU complexes, increased mitochondrial calcium uptake and increased vulnerability of neurons for calcium-induced cell death. A reduction of calcium influx into the cytosol of Purkinje cells rescues ataxia in an AFG3L2-deficient mouse model. In this review, we discuss the relationship between the m-AAA protease and mitochondrial calcium homeostasis and its relevance for neurodegeneration and describe a novel mouse model lacking MCU specifically in Purkinje cells. Our results pledge for a novel view on m-AAA proteases that integrates their pleiotropic functions in mitochondria to explain the pathogenesis of associated neurodegenerative disorders.

  4. Research of calcium oxide hydration in calcium nitrate solutions

    Directory of Open Access Journals (Sweden)

    M.A. Oliynyk

    2016-09-01

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

  5. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

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

  6. Uptake of [N-Me-3H]-choline by synaptosomes from the central nervous system of Locusta migratoria

    International Nuclear Information System (INIS)

    Breer, H.

    1982-01-01

    The accumulation of 3H-choline by isolated synaptosomes from the central nervous system of locust was studied at concentrations varying from 0.05 to 40 microM. Kinetic analysis of the saturable process revealed a high-affinity and a low-affinity system. The high-affinity uptake was competitively inhibited by hemicholinium-3 and was absolutely dependent on external sodium. Elevated potassium concentrations inhibited choline uptake. The choline uptake by insect synaptosomes was found to be remarkably resistant to a variety of metabolic inhibitors. The reduced choline uptake under depolarizing conditions (high potassium concentration or veratridine) in the absence of calcium implies that electrochemical gradients are important for high-affinity choline uptake. Depolarization of preloaded synaptosomes under appropriate conditions resulted in a significant release of newly accumulated choline radioactivity

  7. 21 CFR 184.1207 - Calcium lactate.

    Science.gov (United States)

    2010-04-01

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

  8. Shikonin increases glucose uptake in skeletal muscle cells and improves plasma glucose levels in diabetic Goto-Kakizaki rats.

    Directory of Open Access Journals (Sweden)

    Anette I Öberg

    Full Text Available BACKGROUND: There is considerable interest in identifying compounds that can improve glucose homeostasis. Skeletal muscle, due to its large mass, is the principal organ for glucose disposal in the body and we have investigated here if shikonin, a naphthoquinone derived from the Chinese plant Lithospermum erythrorhizon, increases glucose uptake in skeletal muscle cells. METHODOLOGY/PRINCIPAL FINDINGS: Shikonin increases glucose uptake in L6 skeletal muscle myotubes, but does not phosphorylate Akt, indicating that in skeletal muscle cells its effect is medaited via a pathway distinct from that used for insulin-stimulated uptake. Furthermore we find no evidence for the involvement of AMP-activated protein kinase in shikonin induced glucose uptake. Shikonin increases the intracellular levels of calcium in these cells and this increase is necessary for shikonin-mediated glucose uptake. Furthermore, we found that shikonin stimulated the translocation of GLUT4 from intracellular vesicles to the cell surface in L6 myoblasts. The beneficial effect of shikonin on glucose uptake was investigated in vivo by measuring plasma glucose levels and insulin sensitivity in spontaneously diabetic Goto-Kakizaki rats. Treatment with shikonin (10 mg/kg intraperitoneally once daily for 4 days significantly decreased plasma glucose levels. In an insulin sensitivity test (s.c. injection of 0.5 U/kg insulin, plasma glucose levels were significantly lower in the shikonin-treated rats. In conclusion, shikonin increases glucose uptake in muscle cells via an insulin-independent pathway dependent on calcium. CONCLUSIONS/SIGNIFICANCE: Shikonin increases glucose uptake in skeletal muscle cells via an insulin-independent pathway dependent on calcium. The beneficial effects of shikonin on glucose metabolism, both in vitro and in vivo, show that the compound possesses properties that make it of considerable interest for developing novel treatment of type 2 diabetes.

  9. Root uptake of transuranic elements

    International Nuclear Information System (INIS)

    Schulz, R.K.

    1977-01-01

    The uptake of elements by plant roots is one of the important pathways of entry of many elements into the food chain of man. Data are cited showing plutonium concentration ratios, plant/soil, ranging from 10 -10 to 10 -3 . Concentration ratios for americium range from 10 -7 to 10 +1 . Limited experiments with curium and neptunium indicate that root uptake of curium is similar to that of americium and that plant uptake of neptunium is substantially larger than that of curium and americium. The extreme ranges of concentration ratios cited for plutonium and americium are due to a number of causes. Experimental conditions such as very intensive cropping will lead to abnormally high concentration ratios. In some experiments, addition of chelating agents markedly increased plant root uptake of transuranic elements. Particle size and composition of the source material influenced uptake of the transuranics by plants. Translocation within the plant, and soil factors such as pH and organic matter content, all affect concentration ratios

  10. Radiostrontium uptake by plants from different soil types in Kazakhstan

    International Nuclear Information System (INIS)

    Savinkov, A.; Semioshkina, N.; Howard, B.J.; Voigt, G.

    2007-01-01

    The transfer of 90 Sr to a range of different plant species grown on a range of different soil types in Kazakhstan, including three from the Semipalatinsk Test Site (STS), has been measured in a lysimeter experiment. 90 Sr uptake by Stipa spp was significantly higher than for other vegetation species. The uptake of 90 Sr from chernozem was significantly lower than that from the other soil types which is consistent with other literature. There was a significant negative relationship between 90 Sr uptake and calcium, humus and CEC concentration in the soil for Agropyrum spp, Artemisia spp but not for Stipa spp or Bromus spp. The transfer to vegetation from soil has been quantified using the aggregated transfer coefficients for each species. Tag values range from 0.6 to 11.9 m 2 kg -1 x 10 -3 over all measurements. The transfer of 90 Sr to plants from the Kazakh soils was low compared to previously reported data and to that given from literature reviews

  11. Radiostrontium uptake by plants from different soil types in Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Savinkov, A. [Scientific Research Agricultural Institute of the National Biotechnology Center, Ministry for Science and Higher Education of the Republic of Kazakhstan (SRAI), 480544, Gvardeiski (Kazakhstan)]. E-mail: Chebotar@srai.kz; Semioshkina, N. [GSF-Institut fuer Strahlenschutz, Ingolstaedter Land str.1, D-85764, Neuherberg (Germany)]. E-mail: semi@gsf.de; Howard, B.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: bjho@ceh.ac.uk; Voigt, G. [Agency' s Laboratories - Seibersdorf, IAEA, Vienna (Austria)]. E-mail: g.voigt@iaea.org

    2007-02-01

    The transfer of {sup 90}Sr to a range of different plant species grown on a range of different soil types in Kazakhstan, including three from the Semipalatinsk Test Site (STS), has been measured in a lysimeter experiment. {sup 90}Sr uptake by Stipa spp was significantly higher than for other vegetation species. The uptake of {sup 90}Sr from chernozem was significantly lower than that from the other soil types which is consistent with other literature. There was a significant negative relationship between {sup 90}Sr uptake and calcium, humus and CEC concentration in the soil for Agropyrum spp, Artemisia spp but not for Stipa spp or Bromus spp. The transfer to vegetation from soil has been quantified using the aggregated transfer coefficients for each species. Tag values range from 0.6 to 11.9 m{sup 2} kg {sup -1}x 10{sup -3} over all measurements. The transfer of {sup 90}Sr to plants from the Kazakh soils was low compared to previously reported data and to that given from literature reviews.

  12. Crystal structure of the epithelial calcium channel TRPV6.

    Science.gov (United States)

    Saotome, Kei; Singh, Appu K; Yelshanskaya, Maria V; Sobolevsky, Alexander I

    2016-06-23

    Precise regulation of calcium homeostasis is essential for many physiological functions. The Ca(2+)-selective transient receptor potential (TRP) channels TRPV5 and TRPV6 play vital roles in calcium homeostasis as Ca(2+) uptake channels in epithelial tissues. Detailed structural bases for their assembly and Ca(2+) permeation remain obscure. Here we report the crystal structure of rat TRPV6 at 3.25 Å resolution. The overall architecture of TRPV6 reveals shared and unique features compared with other TRP channels. Intracellular domains engage in extensive interactions to form an intracellular 'skirt' involved in allosteric modulation. In the K(+) channel-like transmembrane domain, Ca(2+) selectivity is determined by direct coordination of Ca(2+) by a ring of aspartate side chains in the selectivity filter. On the basis of crystallographically identified cation-binding sites at the pore axis and extracellular vestibule, we propose a Ca(2+) permeation mechanism. Our results provide a structural foundation for understanding the regulation of epithelial Ca(2+) uptake and its role in pathophysiology.

  13. Why Calcium? How Calcium Became the Best Communicator*

    Science.gov (United States)

    Carafoli, Ernesto; Krebs, Joachim

    2016-01-01

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

  14. Why Calcium? How Calcium Became the Best Communicator.

    Science.gov (United States)

    Carafoli, Ernesto; Krebs, Joachim

    2016-09-30

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

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

    NARCIS (Netherlands)

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

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had

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

    National Research Council Canada - National Science Library

    Pochet, Roland; Donato, Rosario

    2000-01-01

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

  17. Regulation of taurine transport at the blood-placental barrier by calcium ion, PKC activator and oxidative stress conditions

    Directory of Open Access Journals (Sweden)

    Lee Na-Young

    2010-08-01

    Full Text Available Abstract Background In the present study, we investigated the changes of uptake and efflux transport of taurine under various stress conditions using rat conditionally immortalized syncytiotrophoblast cell line (TR-TBT cells, as in vitro blood-placental barrier (BPB model. Methods The transport of taurine in TR-TBT cells were characterized by cellular uptake study using radiolabeled taurine. The efflux of taurine was measured from the amount of radiolabeled taurine remaining in the cells after the uptake of radiolabeled taurine for 60 min. Results Taurine uptake was significantly decreased by phosphorylation of protein kinase C (PKC activator in TR-TBT cells. Also, calcium ion (Ca2+ was involved in taurine transport in TR-TBT cells. Taurine uptake was inhibited and efflux was enhanced under calcium free conditions in the cells. In addition, oxidative stress induced the change of taurine transport in TR-TBT cells, but the changes were different depending on the types of oxidative stress inducing agents. Tumor necrosis factor-α (TNF-α, lipopolysaccharide (LPS and diethyl maleate (DEM significantly increased taurine uptake, but H2O2 and nitric oxide (NO donor decreased taurine uptake in the cells. Taurine efflux was down-regulated by TNF-α in TR-TBT cells. Conclusion Taurine transport in TR-TBT cells were regulated diversely at extracellular Ca2+ level, PKC activator and oxidative stress conditions. It suggested that variable stresses affected the taurine supplies from maternal blood to fetus and taurine level of fetus.

  18. Use of digitonin permeabilization for characterization of calcium incorporated into. beta. cells in response to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wesslen, N [Uppsala Univ. (Sweden)

    1985-01-01

    ..beta.. cell-rich pancreatic islets were used to characterize /sup 45/Ca uptake into pools with different sensitivities to permeabilization with digitonin. The plasma and secretory granule membranes were among the membranes most sensitive to digitonin treatment whereas the mitochondria were more resistant. Most of the /sup 45/Ca incorporated in response to glucose was found in a fraction released after exposure to a high concentration of digitonin. The results suggest that glucose promotes active sequestration of calcium in mitochondria and that the uptake of /sup 45/Ca in the secretory granules in secondary to a raised cytosolic Ca/sup 2 +/ activity.

  19. Lactate, Glucose and Oxygen Uptake in Human Brain During Recovery from Maximal Exercise

    DEFF Research Database (Denmark)

    Kojiro, I.; Schmalbruch, I.K.; Quistorff, B.

    1999-01-01

    Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake......Skeletal muscle, brain lactate uptake, brain oxygen uptake, energy metabolism, brain glucose uptake...

  20. Estimating the biophysical properties of neurons with intracellular calcium dynamics.

    Science.gov (United States)

    Ye, Jingxin; Rozdeba, Paul J; Morone, Uriel I; Daou, Arij; Abarbanel, Henry D I

    2014-06-01

    We investigate the dynamics of a conductance-based neuron model coupled to a model of intracellular calcium uptake and release by the endoplasmic reticulum. The intracellular calcium dynamics occur on a time scale that is orders of magnitude slower than voltage spiking behavior. Coupling these mechanisms sets the stage for the appearance of chaotic dynamics, which we observe within certain ranges of model parameter values. We then explore the question of whether one can, using observed voltage data alone, estimate the states and parameters of the voltage plus calcium (V+Ca) dynamics model. We find the answer is negative. Indeed, we show that voltage plus another observed quantity must be known to allow the estimation to be accurate. We show that observing both the voltage time course V(t) and the intracellular Ca time course will permit accurate estimation, and from the estimated model state, accurate prediction after observations are completed. This sets the stage for how one will be able to use a more detailed model of V+Ca dynamics in neuron activity in the analysis of experimental data on individual neurons as well as functional networks in which the nodes (neurons) have these biophysical properties.

  1. ATP stimulates calcium influx in primary astrocyte cultures

    International Nuclear Information System (INIS)

    Neary, J.T.; van Breemen, C.; Forster, E.; Norenberg, L.O.; Norenberg, M.D.

    1988-01-01

    The effect of ATP and other purines on 45 Ca uptake was studied in primary cultures of rat astrocytes. Treatment of the cells with ATP for 1 to 30 min brought about an increase in cellular 45 Ca. Stimulation of calcium influx by ATP was investigated using a 90 sec exposure to 45 Ca and over a concentration range of 0.1 nM to 3 mM; a biphasic dose-response curve was obtained with EC50 values of 0.3 nM and 9 uM, indicating the presence of low and high affinity purinergic binding sites. Similar levels of 45 Ca influx at 90 sec were observed with ATP, ADP and adenosine (all at 100 uM). Prior treatment of the cultures with LaCl3 blocked the purine-induced 45 Ca influx. These findings indicate that one pathway for calcium entry in astrocytes involves purinergic receptor-operated, calcium channels

  2. 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 ...

  3. Absorption and distribution of calcium (labelled with 45Ca) applied after harvest to Asian pear (Pyrus pyrifolia) fruits

    International Nuclear Information System (INIS)

    Bhat, A.R.; Dhatt, A.S.; Dhillon, K.S.; Dhillon, S.K.

    1993-01-01

    Most of the disorders related to calcium are due to its unequal distribution within the plant rather than poor uptake. Immediately after fruit set, calcium uptake by roots as well as its translocation to developing fruit is extensive. However, the absorbed calcium does not reach the fruit in desired amounts during the subsequent fruit development stages and thereby, resulting in physiological disorders. Some corky spots underneath the peel of the fruit at harvest or during storage have been observed in Asian pear (cv. Patharnakh) which is extensively grown in northern India. There is need to increase the Ca concentration in the body of the fruit to prolong its life. The present investigation was, therefore, undertaken to study the absorption and distribution of post-harvest applied Ca in Asian pear fruit using radiotracer techniques. (author). 6 refs., 3 tabs

  4. Lead in calcium supplements (abstract)

    International Nuclear Information System (INIS)

    Rehman, S.; Khalid, N.

    2011-01-01

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

  5. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Hilbert

    1962-12-15

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

  6. Transcriptional expression analysis of genes involved in regulation of calcium translocation and storage in finger millet (Eleusine coracana L. Gartn.).

    Science.gov (United States)

    Mirza, Neelofar; Taj, Gohar; Arora, Sandeep; Kumar, Anil

    2014-10-25

    Finger millet (Eleusine coracana) variably accumulates calcium in different tissues, due to differential expression of genes involved in uptake, translocation and accumulation of calcium. Ca(2+)/H(+) antiporter (CAX1), two pore channel (TPC1), CaM-stimulated type IIB Ca(2+) ATPase and two CaM dependent protein kinase (CaMK1 and 2) homologs were studied in finger millet. Two genotypes GP-45 and GP-1 (high and low calcium accumulating, respectively) were used to understand the role of these genes in differential calcium accumulation. For most of the genes higher expression was found in the high calcium accumulating genotype. CAX1 was strongly expressed in the late stages of spike development and could be responsible for accumulating high concentrations of calcium in seeds. TPC1 and Ca(2+) ATPase homologs recorded strong expression in the root, stem and developing spike and signify their role in calcium uptake and translocation, respectively. Calmodulin showed strong expression and a similar expression pattern to the type IIB ATPase in the developing spike only and indicating developing spike or even seed specific isoform of CaM affecting the activity of downstream target of calcium transportation. Interestingly, CaMK1 and CaMK2 had expression patterns similar to ATPase and TPC1 in various tissues raising a possibility of their respective regulation via CaM kinase. Expression pattern of 14-3-3 gene was observed to be similar to CAX1 gene in leaf and developing spike inferring a surprising possibility of CAX1 regulation through 14-3-3 protein. Our results provide a molecular insight for explaining the mechanism of calcium accumulation in finger millet. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Postcountershock myocardial damage after pretreatment with adrenergic and calcium channel antagonists in halothane-anesthetized dogs

    Energy Technology Data Exchange (ETDEWEB)

    Gaba, D.M.; Metz, S.; Maze, M.

    1985-05-01

    Transthoracic electric countershock can cause necrotic myocardial lesions in humans as well as experimental animals. The authors investigated the effect on postcountershock myocardial damage of pretreatment with prazosin, an alpha-1 antagonist; L-metoprolol, a beta-1 antagonist, and verapamil, a calcium channel-blocking agent. Twenty dogs were anesthetized with halothane and given two transthoracic countershocks of 295 delivered joules each after drug or vehicle treatment. Myocardial injury was quantitated 24 h following countershock by measuring the uptake of technetium-99m pyrophosphate in the myocardium. Elevated technetium-99m pyrophosphate uptake occurred in visible lesions in most dogs regardless of drug treatment. For each of four parameters of myocardial damage there was no statistically significant difference between control animals and those treated with prazosin, metoprolol, or verapamil. These data suggest that adrenergic or calcium channel-mediated mechanisms are not involved in the pathogenesis of postcountershock myocardial damage.

  8. Hydrogen peroxide-mediated oxidative stress disrupts calcium binding on calmodulin: More evidence for oxidative stress in vitiligo

    International Nuclear Information System (INIS)

    Schallreuter, K.U.; Gibbons, N.C.J.; Zothner, C.; Abou Elloof, M.M.; Wood, J.M.

    2007-01-01

    Patients with acute vitiligo have low epidermal catalase expression/activities and accumulate 10 -3 M H 2 O 2 . One consequence of this severe oxidative stress is an altered calcium homeostasis in epidermal keratinocytes and melanocytes. Here, we show decreased epidermal calmodulin expression in acute vitiligo. Since 10 -3 M H 2 O 2 oxidises methionine and tryptophan residues in proteins, we examined calcium binding to calmodulin in the presence and absence of H 2 O 2 utilising 45 calcium. The results showed that all four calcium atoms exchanged per molecule of calmodulin. Since oxidised calmodulin looses its ability to activate calcium ATPase, enzyme activities were followed in full skin biopsies from lesional skin of patients with acute vitiligo (n = 6) and healthy controls (n = 6). The results yielded a 4-fold decrease of ATPase activities in the patients. Computer simulation of native and oxidised calmodulin confirmed the loss of all four calcium ions from their specific EF-hand domains. Taken together H 2 O 2 -mediated oxidation affects calcium binding in calmodulin leading to perturbed calcium homeostasis and perturbed L-phenylalanine-uptake in the epidermis of acute vitiligo

  9. [Calcium and vitamin D in bone metabolism: Clinical importance for fracture treatment].

    Science.gov (United States)

    Amling, M

    2015-12-01

    A balanced calcium homeostasis is of critical importance not only for bone remodeling, the physiological process of bone resorption and bone formation that constantly renews bone throughout life but also for normal fracture healing. Given that disturbances of calcium homeostasis are present in 50 % of the German population and that this might result in delayed fracture healing after correct surgical treatment, this paper focusses on calcium and vitamin D in the daily practice in orthopedics and trauma surgery. To ensure the required enteral calcium uptake the following three conditions are required: (1) sufficient calcium intake via the nutrition, (2) a 25-hydroxyvitamin D serum level > 30 µg/l and (3) the presence of sufficient gastric acidification. Given the endemic vitamin D deficiency in Germany as well as the constantly increasing number of people using proton pump inhibitors on a regular basis, it is necessary to closely connect trauma orthopedic surgery and osteological treatment. The first issue to be dealt with is to control and if needed normalize calcium homeostasis in order to allow a normal undisturbed fracture healing process after both conservative as well as operative treatment of fractures.

  10. Precipitation of calcium, magnesium, strontium and barium in tissues of four Acacia species (Leguminosae: Mimosoideae).

    Science.gov (United States)

    He, Honghua; Bleby, Timothy M; Veneklaas, Erik J; Lambers, Hans; Kuo, John

    2012-01-01

    Precipitation of calcium in plants is common. There are abundant studies on the uptake and content of magnesium, strontium and barium, which have similar chemical properties to calcium, in comparison with those of calcium in plants, but studies on co-precipitation of these elements with calcium in plants are rare. In this study, we compared morphologies, distributional patterns, and elemental compositions of crystals in tissues of four Acacia species grown in the field as well as in the glasshouse. A comparison was also made of field-grown plants and glasshouse-grown plants, and of phyllodes of different ages for each species. Crystals of various morphologies and distributional patterns were observed in the four Acacia species studied. Magnesium, strontium and barium were precipitated together with calcium, mainly in phyllodes of the four Acacia species, and sometimes in branchlets and primary roots. These elements were most likely precipitated in forms of oxalate and sulfate in various tissues, including epidermis, mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex. In most cases, precipitation of calcium, magnesium, strontium and barium was biologically induced, and elements precipitated differed between soil types, plant species, and tissues within an individual plant; the precipitation was also related to tissue age. Formation of crystals containing these elements might play a role in regulating and detoxifying these elements in plants, and protecting the plants against herbivory.

  11. Hg uptake in ureteral obstructions

    International Nuclear Information System (INIS)

    Desgrez, J.P.; Bourguignon, M.; Raynaud, C.; CEA, 91 - Orsay

    1976-01-01

    In the presence of a total obstruction the results obtained with the Hg uptake test, as indeed with other functional tests, inform on the value of the kidney function at the time but have no prognostic value where repair possibilities are concerned. Some preliminary results seem to show however that very soon after the obstacle is removed, by the 10th or 15th day perhaps, quantitative functional tests may once more be used to evaluate the functional prognosis. This would mean that by waiting about two weeks after the disappearance of a total obstruction the Hg uptake test may again be used in all confidence. In order to check this deduction, which is based on slender evidence but which nevertheless has important practical implications, the measurement of the Hg uptake rate during the days following removal of the obstacle appears essential. In long-standing partial obstructions the Hg uptake rate gives an accurate assessment of the functional balance and helps considerably in the choice of therapy [fr

  12. Cellular uptake of metallated cobalamins

    DEFF Research Database (Denmark)

    Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry

    2016-01-01

    Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN...

  13. Tumor uptake of radioruthenium compounds

    International Nuclear Information System (INIS)

    Srivastava, S.C.; Richards, P.; Meinken, G.E.; Larson, S.M.; Grunbaum, Z.

    1980-01-01

    The use of ruthenium-97 as a scintigraphic agent, particularly for tumor localization, is investigated. The tumor uptake of ruthenium chloride and ruthenium-labelled transferrin is evaluated and their application as tumor-imagine agents is compared to gallium-67 citrate

  14. Octreotide Uptake in Parathyroid Adenoma

    Directory of Open Access Journals (Sweden)

    Seyhan Karaçavuş

    2012-08-01

    Full Text Available The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positive parathyroid tumors. (MIRT 2012;21:77-79

  15. Electrophysical properties of calcium vanadates

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  16. Preparation of calcium phosphate paste

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa

    2010-01-01

    Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

  17. Ocean carbon uptake and storage

    International Nuclear Information System (INIS)

    Tilbrook, Bronte

    2007-01-01

    Full text: The ocean contains about 95% of the carbon in the atmosphere, ocean and land biosphere system, and is of fundamental importance in regulating atmospheric carbon dioxide concentrations. In the 1990s an international research effort involving Australia was established to determine the uptake and storage of anthropogenic C02 for all major ocean basins. The research showed that about 118 of the 244 + 20 billion tons of the anthropogenic carbon emitted through fossil fuel burning and cement production has been stored in the ocean since preindustrial times, thus helping reduce the rate of increase in atmospheric C02. The research also showed the terrestrial biosphere has been a small net source of C02 (39 ± 28 billion tons carbon) to the atmosphere over the same period. About 60% of the total ocean inventory of the anthropogenic C02 was found in the Southern Hemisphere, with most in the 30 0 S to 50 0 S latitude band. This mid-latitude band is where surface waters are subducted as Mode and Intermediate waters, which is a major pathway controlling ocean C02 uptake. High storage (23% of the total) also occurs in the North Atlantic, associated with deep water formation in that basin. The ocean uptake and storage is expected to increase in the coming decades as atmospheric C02 concentrations rise. However, a number of feedback mechanisms associated with surface warming, changes in circulation, and biological effects are likely to impact on the uptake capacity. The accumulation or storage-of the C02 in the ocean is also the major driver of ocean acidification with potential to disrupt marine ecosystems. This talk will describe the current understanding of the ocean C02 uptake and storage and a new international research strategy to detect how the ocean uptake and storage will evolve on interannual through decadal scales. Understanding the ocean response to increasing atmospheric C02 will be a key element in managing future C02 increases and establishing

  18. FDG uptake in the stomach

    International Nuclear Information System (INIS)

    Yun, M. J.; Cho, H. J.; Cho, E. H.; Kim, T. S.; Kang, W. J.; Lee, J. D.

    2007-01-01

    This study was performed to evaluate histopathologic features of advanced gastric cancer (AGC) to predict FDG uptake on PET. 153 patients(102 men; mean age, 55 y) were diagnosed with AGC by surgery were included in this study. PET images were evaluated by visual and semi-quantitative analysis of FDG uptake in primary tumors. Primary tumors size were measured and divided according to Borrmann classification. Tumor histology was classified under WHO classification, depth of invasion and Iymphovascular invasion. The tumors were also grouped by high cellular(cellularity = 50%) and low cellular group (<50%). Microscopic growth type was based on Lauren classification. Stromal fibrosis degree and inflammatory cell infiltration amount was graded as low(none∼mild), or high(moderate∼severe). Lymph node metastases was assessed in all patients. Statistical analyses were performed to evaluate differences in SUV as to histopathologic factors. Of the 153 patients, 21 patients(14%) had primary tumor invisible on initial whole body images. After water ingestion, the tumors became visible in 15 of the 21 patients due to disappearance of physiologic stomach uptake. Polypoid or ulcerofungating tumors, high cellularity, intestinal growth pattern, and larger tumors significantly predicted increased tumor SUVs. Well or moderately differentiated adenocarcinoma tended to show high cellularity and intestinal growth pattern. Poorly differentiated adenocarcinoma had diverse spectrum of histopathology. Signet ring cell carcinomas were mostly ulceroinfiltrative or diffusely infiltrative in macroscopic type and diffuse in microscopic tumor growth. Mucinous adenocarcinomas were mostly low in cellularity. FDG uptake patterns are useful in representing histopathologic characteristics of the entire tumor in gastric cancers. The degree of FDG uptake depends on tumor size, macroscopic type, cellularity, and microscopic growth pattern and it shows no association with well known important prognostic

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

    Science.gov (United States)

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

    1991-12-01

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

  20. Relation between the location of elements in the periodic table and tumor-uptake rate

    Energy Technology Data Exchange (ETDEWEB)

    Ando, A; Ando, I; Hiraki, T; Hisada, K

    1985-01-01

    The bipositive ions and anions, with few exceptions, indicated a low tumor uptake rate. On the other hand, compounds of Hg, Au and Bi, which have a strong binding power to protein, showed a high tumor uptake rate. As Hg/sup 2 +/, Au/sup +/ and Bi/sup 3 +/ are soft acids according to the classification of Lewis acids, it was thought that these ions would bind strongly to soft bases (R-SH, R-S-) present in tumor tissue. For many hard acids such as /sup 85/Sr/sup 2 +/, /sup 67/Ga/sup 3 +/, /sup 181/Hf/sup 4 +/, and /sup 95/Nb/sup 5 +/, tumor uptake rates are shown as a function of ionic potentials of the metal ions. Considering the present data and previously reported results, it was presumed that hard acids of trivalence, quadrivalence and pentavalence would replace calcium in the calcium salts of hard bases. Ionic potentials of alkaline metals and Tl were small, but the tumor-uptake rate of these elements indicated various values. As Ge and Sb are bound by covalent bonds to chloride, GeCl/sub 4/ and SbCl/sub 3/ behaved differently from many metallic compounds in tumor tissue.

  1. Calcium and Bone Metabolism Indices.

    Science.gov (United States)

    Song, Lu

    2017-01-01

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

  2. Magnetically responsive calcium carbonate microcrystals.

    Science.gov (United States)

    Fakhrullin, Rawil F; Bikmullin, Aidar G; Nurgaliev, Danis K

    2009-09-01

    Here we report the fabrication of magnetically responsive calcium carbonate microcrystals produced by coprecipitation of calcium carbonate in the presence of citrate-stabilized iron oxide nanoparticles. We demonstrate that the calcite microcrystals obtained possess superparamagnetic properties due to incorporated magnetite nanoparticles and can be manipulated by an external magnetic field. The microcrystals doped with magnetic nanoparticles were utilized as templates for the fabrication of hollow polyelectrolyte microcapsules, which retain the magnetic properties of the sacrificial cores and might be spatially manipulated using a permanent magnet, thus providing the magnetic-field-facilitated delivery and separation of materials templated on magnetically responsive calcite microcrystals.

  3. Localization of calcium in the cyanobiont and gonidial zone of Cycas revoluta Thunb. by microelectrodes, chlorotetracycline, electron spectroscopic imaging and electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    Caiola, M.G.; Canini, A.; Brandizzi, F.

    1994-01-01

    Ionic calcium concentration was measured in the gonidial zone of fresh coralloid roots by means of calcium microelectrodes. It was 10 -6 M in the apical segments of coralloid roots and increased to 10 -5 M in the gonidial zones of median and basal segments. Loosely membrane-bound calcium was evidenced by using chloro-tetracycline (CTC) or ethylene glycol-bis-(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and CTC, in cell walls of columnar cells of Cycas and in the cytoplasm of cyanobiont. Sub-cellular localization of calcium was obtained by electron spectroscopic imaging (ESI) and electron energy loss spectroscopy (EELS) analyses applied at transmission electron microscopy on thin, unstained sections of gonidial zone of coralloid roots. By means of these techniques, bound-calcium was detected inside the mucilage of apical and median segments whereas, in the basal segments, it was completely absent. In the heterocysts of apical segments of coralloid, calcium was localized on the envelope, cell walls, thylakoids and cyanophycin granules. In the gonidial zone of the basal segments, dead or degenerating heterocysts completely lacked calcium. Therefore, the high ionic calcium amounts detected in the gonidial zone of median and basal segments could represent a minor calcium uptake by the cells or release by lysed ones. The decreases in nitrogenase activity recorded in the median and basal segments of the coralloid roots paralleled the decrease in calcium amount in heterocyst envelope. (authors)

  4. Surfactant protein A (SP-A) inhibits agglomeration and macrophage uptake of toxic amine modified nanoparticles.

    Science.gov (United States)

    McKenzie, Zofi; Kendall, Michaela; Mackay, Rose-Marie; Whitwell, Harry; Elgy, Christine; Ding, Ping; Mahajan, Sumeet; Morgan, Cliff; Griffiths, Mark; Clark, Howard; Madsen, Jens

    2015-01-01

    The lung provides the main route for nanomaterial exposure. Surfactant protein A (SP-A) is an important respiratory innate immune molecule with the ability to bind or opsonise pathogens to enhance phagocytic removal from the airways. We hypothesised that SP-A, like surfactant protein D, may interact with inhaled nanoparticulates, and that this interaction will be affected by nanoparticle (NP) surface characteristics. In this study, we characterise the interaction of SP-A with unmodified (U-PS) and amine-modified (A-PS) polystyrene particles of varying size and zeta potential using dynamic light scatter analysis. SP-A associated with both 100 nm U-PS and A-PS in a calcium-independent manner. SP-A induced significant calcium-dependent agglomeration of 100 nm U-PS NPs but resulted in calcium-independent inhibition of A-PS self agglomeration. SP-A enhanced uptake of 100 nm U-PS into macrophage-like RAW264.7 cells in a dose-dependent manner but in contrast inhibited A-PS uptake. Reduced association of A-PS particles in RAW264.7 cells following pre-incubation of SP-A was also observed with coherent anti-Stokes Raman spectroscopy. Consistent with these findings, alveolar macrophages (AMs) from SP-A(-/-) mice were more efficient at uptake of 100 nm A-PS compared with wild type C57Bl/6 macrophages. No difference in uptake was observed with 500 nm U-PS or A-PS particles. Pre-incubation with SP-A resulted in a significant decrease in uptake of 100 nm A-PS in macrophages isolated from both groups of mice. In contrast, increased uptake by AMs of U-PS was observed after pre-incubation with SP-A. Thus we have demonstrated that SP-A promotes uptake of non-toxic U-PS particles but inhibits the clearance of potentially toxic A-PS particles by blocking uptake into macrophages.

  5. Effects of inorganic phosphate and ADP on calcium handling by the sarcoplasmic reticulum in rat skinned cardiac muscles.

    Science.gov (United States)

    Xiang, J Z; Kentish, J C

    1995-03-01

    The aim was to investigate whether, and how, increases in inorganic phosphate (Pi) and ADP, similar to those occurring intracellularly during early myocardial ischaemia, affect the calcium handling of the sarcoplasmic reticulum. Rat ventricular trabeculae were permeabilised with saponin. The physiological process of calcium induced calcium release (CICR) from the muscle sarcoplasmic reticulum was triggered via flash photolysis of the "caged Ca2+", nitr-5. Alternatively, calcium release was induced by rapid application of caffeine to give an estimate of sarcoplasmic reticular calcium loading. The initial rate of sarcoplasmic reticular calcium pumping was also assessed by photolysis of caged ATP at saturating [Ca2+]. Myoplasmic [Ca2+] (using fluo-3) and isometric force were measured. Pi (2-20 mM) significantly depressed the magnitude of CICR and the associated force transient. Sarcoplasmic reticular calcium loading was inhibited even more than CICR by Pi, suggesting that reduced calcium loading could account for all of the inhibitory effect of Pi on CICR and that Pi may slightly activate the calcium release mechanism. The reduced sarcoplasmic reticular calcium loading seemed to be due to a fall in the free energy of ATP hydrolysis (delta GATP) available for the calcium pump, since equal decreases in delta GATP produced by adding both Pi and ADP in various ratios caused similar falls in the calcium loading of the sarcoplasmic reticulum. The caged ATP experiments indicated that Pi (20 mM) did not affect the rate constant of sarcoplasmic reticular calcium uptake. ADP (10 mM) alone, or with 1 mM Pi, inhibited calcium loading. In spite of this, ADP (10 mM) did not alter CICR and, when 1 mM Pi was added, ADP increased CICR above control. An increase in intracellular Pi reduces sarcoplasmic reticular calcium loading and thus depresses the CICR. This could be an important contributing factor in the hypoxic or ischaemic contractile failure of the myocardium. However the

  6. Incidental Diagnosis of Carcinoma of the Bladder Due to Uptake of 99mTc-MDP

    International Nuclear Information System (INIS)

    Damle, Nishikant A; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar; Subbarao, Kiran; Singh, Prabhjot; Mishra, Rohini; Das, Nitendra Lal; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar

    2012-01-01

    A bone scan was per-formed using 740 MBq (29 mCi) 99 mTc-MDP. Whole-body planar images were acquired 3 h after injection (Fig. 1). Soft tissue uptake of 99 mTc-MDP is described in various benign and malignant conditions. It is known to accumulate in adenocarcinoma of lung, primary breast cancer, and colonic carcinoma among others. The postulated causes of 99 mTc-MDP uptake in extraosseous neoplasms are numerous and include tumor vascularity, inflammation, local pH factors, altered calcium metabolism, hormonal influences and cell wall damage. Our case shows that TCC of the bladder was incidentally diagnosed due to MDP uptake in multiple bladder polyps detected on a bone scan done for low backache in an 80-year-old man

  7. Inhibiting the Mitochondrial Calcium Uniporter during Development Impairs Memory in Adult Drosophila

    Directory of Open Access Journals (Sweden)

    Ilaria Drago

    2016-09-01

    Full Text Available The uptake of cytoplasmic calcium into mitochondria is critical for a variety of physiological processes, including calcium buffering, metabolism, and cell survival. Here, we demonstrate that inhibiting the mitochondrial calcium uniporter in the Drosophila mushroom body neurons (MBn—a brain region critical for olfactory memory formation—causes memory impairment without altering the capacity to learn. Inhibiting uniporter activity only during pupation impaired adult memory, whereas the same inhibition during adulthood was without effect. The behavioral impairment was associated with structural defects in MBn, including a decrease in synaptic vesicles and an increased length in the axons of the αβ MBn. Our results reveal an in vivo developmental role for the mitochondrial uniporter complex in establishing the necessary structural and functional neuronal substrates for normal memory formation in the adult organism.

  8. Inhibiting the Mitochondrial Calcium Uniporter during Development Impairs Memory in Adult Drosophila.

    Science.gov (United States)

    Drago, Ilaria; Davis, Ronald L

    2016-09-06

    The uptake of cytoplasmic calcium into mitochondria is critical for a variety of physiological processes, including calcium buffering, metabolism, and cell survival. Here, we demonstrate that inhibiting the mitochondrial calcium uniporter in the Drosophila mushroom body neurons (MBn)-a brain region critical for olfactory memory formation-causes memory impairment without altering the capacity to learn. Inhibiting uniporter activity only during pupation impaired adult memory, whereas the same inhibition during adulthood was without effect. The behavioral impairment was associated with structural defects in MBn, including a decrease in synaptic vesicles and an increased length in the axons of the αβ MBn. Our results reveal an in vivo developmental role for the mitochondrial uniporter complex in establishing the necessary structural and functional neuronal substrates for normal memory formation in the adult organism. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Interactions of calcium homeostasis, acetylcholine metabolism, behavior and 3, 4-diaminopyridine during aging

    International Nuclear Information System (INIS)

    Gibson, G.E.; Peterson, C.

    1986-01-01

    Acetylcholine synthesis declines with aging in both whole brain and in various brain regions. Since neither enzyme activities nor acetylcholine concentrations, accurately reflect the dynamics of the cholinergic system, in vivo acetylcholine formation was measured. Incorporation of U-C 14-glucose of 2 H 4 choline into whole brain acetylcholine decreases from 100% (3 months) in two strains of mice. The diminished synthesis is apparently not due to a lack of precursor availability because U- C 14-glucose and 2 H 4 choline entry into the brain is similar at all ages. It is shown that altered brain calcium homeostasis during aging may underlie the deficits in acetylcholine metabolism, as well as those in behavior. Diminished calcium uptake during aging parallels the decline in the calcium dependent release of acetylcholine

  10. Calcium bioavailability of vegetarian diets in rats: potential application in a bioregenerative life-support system

    Science.gov (United States)

    Nickel, K. P.; Nielsen, S. S.; Smart, D. J.; Mitchell, C. A.; Belury, M. A.

    1997-01-01

    Calcium bioavailability of vegetarian diets containing various proportions of candidate crops for a controlled ecological life-support system (CELSS) was determined by femur 45Ca uptake. Three vegetarian diets and a control diet were labeled extrinsically with 45Ca and fed to 5-wk old male rats. A fifth group of rats fed an unlabeled control diet received an intraperitoneal (IP) injection of 45Ca. There was no significant difference in mean calcium absorption of vegetarian diets (90.80 +/- 5.23%) and control diet (87.85 +/- 5.25%) when calculated as the percent of an IP dose. The amounts of phytate, oxalate, and dietary fiber in the diets did not affect calcium absorption.

  11. Effect of Na, Ca and pH on simultaneous uptake of Cd, Cu, Ni, Pb, and Zn in the water flea Daphnia magna measured using stable isotopes

    International Nuclear Information System (INIS)

    Komjarova, I.; Blust, R.

    2009-01-01

    The present study investigates the effects of Na + , Ca 2+ and pH on the kinetics of Cd, Cu, Ni, Pb, and Zn uptake in Daphnia magna at low exposure concentrations measured using a stable isotope technique. Using experimental data the uptake rate constants were calculated for each metal individually on the basis of total metal concentrations. The copper uptake was not significantly affected by variations in chemical composition of the test medium. Calcium had a suppressing effect on the uptake of Cd, Ni, Pb and Zn. Specifically, Cd and Ni uptake rate constants decreased with increases in calcium concentrations from 0.1 to 2.5 mM. The uptake of Zn and Pb was significantly suppressed only at 2.5 mM Ca. The effect of sodium was less clear. There was no effect of varying sodium concentrations on the Ni uptake rate constants. Cd and Pb showed an increase in uptake rate constants at elevated sodium concentrations (2-8 mM Na + for Cd and 8 mM Na + for Pb). A bell-shaped response on increasing Na + concentrations was observed for Zn with a maximum value of uptake rate constant at the middle value (2 mM Na + ). Variation in pH of the medium affected Cd, Ni and Zn uptake processes. When Daphnia were exposed to acidic conditions (pH 6), the Cd and Ni uptake rate constants were the highest, while similarly low values were observed at neutral and basic conditions. In contrast, the uptake rates of Zn were linearly increasing with increasing pH of the medium.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Dmitry eSamigullin

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...

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

    Science.gov (United States)

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

    2009-01-01

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

  16. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

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

  17. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    Khalikova, M.D.; Avloev, Kh.Kh.; Muhiddinov, Z.K.

    2005-01-01

    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

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  20. Sodium pump activity and calcium relaxation in vascular smooth muscle of deoxycorticosterone acetate-salt rats

    International Nuclear Information System (INIS)

    Soltis, E.E.; Field, F.P.

    1986-01-01

    The Na + -K + pump activity was determined in femoral arterial smooth muscle from deoxycorticosterone acetate (DOCA)-salt hypertensive rats using potassium relaxation and ouabain-sensitive 86 Rb uptake as indices. The membrane-stabilizing effect of calcium and its relation to Na + -K + pump activity also were examined. Femoral arteries from DOCA-salt rats exhibited a greater relaxation in response to potassium addition after contraction with norepinephrine in a low potassium (0.6 mM) Krebs solution. The concentration of potassium required to produce a 50% relaxation was significantly less in DOCA-salt rats. Ouabain-sensitive 86 Rb uptake was significantly greater at 3, 10, and 20 minutes of 86 Rb incubation in femoral arteries from DOCA-salt rats. Linear regression analysis revealed a significant correlation between the uptake of 86 Rb and time of incubation in both control and DOCA-salt rats. A significant difference in the slopes of the regression lines showed that the rate of uptake was greater in DOCA-salt rats. No difference was observed in ouabain-insensitive 86 Rb uptake. A dose-dependent relaxation in response to increasing concentrations of calcium following contraction to norepinephrine was observed in femoral arteries from control and DOCA-salt rats. The relaxation was directly dependent on the level of extracellular potassium and was blocked by ouabain. Femoral arteries from DOCA-salt rats relaxed to a significantly greater extent in response to calcium at each level of potassium when compared with controls. These results provide further evidence for an increase in Na + -K + pump activity in vascular smooth muscle from DOCA-salt hypertensive rats

  1. Comparative evaluation of three diphosphonates: in vitro adsorption (C-14 labeled) and in vivo osteogenic uptake (Tc-99m complexed)

    International Nuclear Information System (INIS)

    Francis, M.D.; Ferguson, D.L.; Tofe, A.J.; Bevan, J.A.; Michaels, S.E.

    1980-01-01

    We have investigated the in vitro adsorption of three C-14-labeled diphosphonates on calcium phosphate. The three are 1-hydroxy[1- 14 C]ethylidene diphosphonate (C-14 HEDP), [ 14 C]methylenediphosphonate (C-14 MDP), and hydroxy[ 14 C]-methylenediphosphonate (C-14 HMDP). All three adsorbed significantly more, per mole of calcium, on amorphous calcium phosphate than on crystalline hydroxyapatite. Among the three diphosphonates, C-14 HMDP adsorbed-on both amorphous and crystalline calcium phosphate-to a greater degree than did the other two bone-seeking agents. Moreover, when HMDP was complexed with Sn(II) and Tc-99m, it produced a significantly higher uptake of Tc-99m, per mg of calcium, in an isolated in vivo site of osteogenesis. The mechanisms of adsorption are discussed relative to the hydroxyl group on the diphosphonate, to the solubility of the calcium salts of the diphosphonates, and to the form of the calcium phosphate. These studies form a working rationale for the clinically observed high contrast obtained with Tc-99m HMDP between normal bone and soft tissue, and between normal and abnormal bone

  2. Importance of mitochondrial calcium uniporter in high glucose-induced endothelial cell dysfunction.

    Science.gov (United States)

    Chen, Wei; Yang, Jie; Chen, Shuhua; Xiang, Hong; Liu, Hengdao; Lin, Dan; Zhao, Shaoli; Peng, Hui; Chen, Pan; Chen, Alex F; Lu, Hongwei

    2017-11-01

    Mitochondrial Ca 2+ overload is implicated in hyperglycaemia-induced endothelial cell dysfunction, but the key molecular events responsible remain unclear. We examined the involvement of mitochondrial calcium uniporter, which mediates mitochondrial Ca 2+ uptake, in endothelial cell dysfunction resulting from high-glucose treatment. Human umbilical vein endothelial cells were exposed to various glucose concentrations and to high glucose (30 mM) following mitochondrial calcium uniporter inhibition or activation with ruthenium red and spermine, respectively. Subsequently, mitochondrial calcium uniporter and mitochondrial calcium uniporter regulator 1 messenger RNA and protein expression was measured by real-time polymerase chain reaction and western blotting. Ca 2+ concentrations were analysed by laser confocal microscopy, and cytoplasmic and mitochondrial oxidative stress was detected using 2',7'-dichlorofluorescein diacetate and MitoSOX Red, respectively. Apoptosis was assessed by annexin V-fluorescein isothiocyanate/propidium iodide staining, and a wound-healing assay was performed using an in vitro model. High glucose markedly upregulated mitochondrial calcium uniporter and mitochondrial calcium uniporter regulator 1 messenger RNA expression, as well as protein production, in a dose- and time-dependent manner with a maximum effect demonstrated at 72 h and 30 mM glucose concentration. Moreover, high-glucose treatment significantly raised both mitochondrial and cytoplasmic Ca 2+ and reactive oxygen species levels, increased apoptosis and compromised wound healing (all p calcium uniporter, respectively. Mitochondrial calcium uniporter plays an important role in hyperglycaemia-induced endothelial cell dysfunction and may constitute a therapeutic target to reduce vascular complications in diabetes.

  3. Calcium channel blockers and Alzheimer's disease★

    Science.gov (United States)

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in Alzheimer's disease therapy. PMID:25767489

  4. 21 CFR 184.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

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

  5. Oxalic acid decreases calcium absorption in rats

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  6. Calcium and Nuclear Signaling in Prostate Cancer

    OpenAIRE

    Ivan V. Maly; Wilma A. Hofmann

    2018-01-01

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

  7. 21 CFR 184.1195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

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

  8. 21 CFR 184.1185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be...

  9. 21 CFR 184.1229 - Calcium stearate.

    Science.gov (United States)

    2010-04-01

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

  10. Calcium Balance in Chronic Kidney Disease.

    Science.gov (United States)

    Hill Gallant, Kathleen M; Spiegel, David M

    2017-06-01

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

  11. 21 CFR 184.1193 - Calcium chloride.

    Science.gov (United States)

    2010-04-01

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

  12. 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...

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

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

    2003-08-01

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

  15. 21 CFR 582.1210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

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

  16. 21 CFR 582.5210 - Calcium oxide.

    Science.gov (United States)

    2010-04-01

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

  17. 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

  18. 21 CFR 182.3225 - Calcium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sorbate. 182.3225 Section 182.3225 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally recognized as...

  19. 21 CFR 582.5230 - Calcium sulfate.

    Science.gov (United States)

    2010-04-01

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

  20. 21 CFR 582.6185 - Calcium acetate.

    Science.gov (United States)

    2010-04-01

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

  1. 21 CFR 582.5195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

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

  2. 21 CFR 582.3225 - Calcium sorbate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sorbate. 582.3225 Section 582.3225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally...

  3. 21 CFR 582.6195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

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

  4. 21 CFR 582.6219 - Calcium phytate.

    Science.gov (United States)

    2010-04-01

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

  5. 21 CFR 582.1207 - Calcium lactate.

    Science.gov (United States)

    2010-04-01

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

  6. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c) Limitations...

  7. 21 CFR 582.1195 - Calcium citrate.

    Science.gov (United States)

    2010-04-01

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

  8. 21 CFR 582.7187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

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

  9. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

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

  10. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the ...

  11. 21 CFR 201.70 - Calcium labeling.

    Science.gov (United States)

    2010-04-01

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

  12. Preparation and properties of calcium zirconate

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  13. 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....

  14. 21 CFR 582.6193 - Calcium chloride.

    Science.gov (United States)

    2010-04-01

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

  15. 21 CFR 582.1193 - Calcium chloride.

    Science.gov (United States)

    2010-04-01

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

  16. 7 CFR 58.434 - Calcium chloride.

    Science.gov (United States)

    2010-01-01

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

  17. Arsenic uptake in bacterial calcite

    Science.gov (United States)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03 Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  18. Arsenic uptake in bacterial calcite

    Energy Technology Data Exchange (ETDEWEB)

    Catelani, Tiziano; Perito, Brunella; Bellucci, Francesco; Lee, Sang Soo; Fenter, Paul; Newville, Matthew G.; Rimondi, Valentina; Pratesi, Giovanni; Costagliola, Pilario

    2018-02-01

    Bio-mediated processes for arsenic (As) uptake in calcite were investigated by means of X-ray Diffraction (XRD) and Xray Absorption Spectroscopy (XAS) coupled with X-ray Fluorescence measurements. The environmental bacterial strain Bacillus licheniformis BD5, sampled at the Bullicame Hot Springs (Viterbo, Central Italy), was used to synthesize calcite from As-enriched growth media. Both liquid and solid cultures were applied to simulate planktonic and biofilm community environments, respectively. Bacterial calcite samples cultured in liquid media had an As enrichment factor (Kd) 50 times higher than that from solid media. The XRD analysis revealed an elongation of the crystal lattice along the c axis (by 0.03Å) for biogenic calcite, which likely resulted from the substitution of larger arsenate for carbonate in the crystal. The XAS data also showed a clear difference in the oxidation state of sorbed As between bacterial and abiotic calcite. Abiotic chemical processes yielded predominantly As(V) uptake whereas bacterial precipitation processes led to the uptake of both As(III) and As(V). The presence of As(III) in bacterial calcite is proposed to result from subsequent reduction of arsenate to arsenite by bacterial activities. To the best of our knowledge, this is the first experimental observation of the incorporation of As(III) in the calcite crystal lattice, revealing a critical role of biochemical processes for the As cycling in nature.

  19. Metal uptake and acute toxicity in zebrafish: Common mechanisms across multiple metals

    Energy Technology Data Exchange (ETDEWEB)

    Alsop, Derek, E-mail: alsopde@mcmaster.ca [Department of Biology, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4K1 (Canada); Wood, Chris M. [Department of Biology, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4K1 (Canada)

    2011-10-15

    All metals tested reduced calcium uptake in zebrafish larvae. However, it was whole body sodium loss that was functionally related to toxicity. The zebrafish larvae acute toxicity assay save time, space and resources. - Abstract: Zebrafish larvae (Danio rerio) were used to examine the mechanisms of action and acute toxicities of metals. Larvae had similar physiological responses and sensitivities to waterborne metals as adults. While cadmium and zinc have previously been shown to reduce Ca{sup 2+} uptake, copper and nickel also decreased Ca{sup 2+} uptake, suggesting that the epithelial transport of all these metals is through Ca{sup 2+} pathways. However, exposure to cadmium, copper or nickel for up to 48 h had little or no effect on total whole body Ca{sup 2+} levels, indicating that the reduction of Ca{sup 2+} uptake is not the acute toxic mechanism of these metals. Instead, mortalities were effectively related to whole body Na{sup +}, which decreased up to 39% after 48 h exposures to different metals around their respective 96 h LC50s. Decreases in whole body K{sup +} were also observed, although they were not as pronounced or frequent as Na{sup +} losses. None of the metals tested inhibited Na{sup +} uptake in zebrafish (Na{sup +} uptake was in fact increased with exposure) and the observed losses of Na{sup +}, K{sup +}, Ca{sup 2+} and Mg{sup 2+} were proportional to the ionic gradients between the plasma and water, indicating diffusive ion loss with metal exposure. This study has shown that there is a common pathway for metal uptake and a common mechanism of acute toxicity across groups of metals in zebrafish. The disruption of ion uptake accompanying metal exposure does not appear to be responsible for the acute toxicity of metals, as has been previously suggested, but rather the toxicity is instead due to total ion loss (predominantly Na{sup +}).

  20. Uptake and retardation of Cl during cement carbonation

    Energy Technology Data Exchange (ETDEWEB)

    Milodowski, A.E.; Rochelle, C.A.; Purser, G. [British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG (United Kingdom)

    2013-07-01

    The presence of {sup 36}Cl in low- and intermediate-level radioactive waste (L/ILW) is of concern in repository performance assessment. Its mobility and its relatively long half-life (302,000 years) could potentially lead to early release from the waste and its return to the biosphere within the 10{sup 6} timescale. Experiments have been undertaken to examine the impact of carbonation on the mineralogical and physical properties of NRVB cement in relation to the degradation of organic material in the L/ILW, and with oil well Type-G cement in relation to borehole sealing for carbon capture and storage. These show that the cements can uptake a significant amount of Cl through the formation of transient secondary calcium chloroaluminate and Cl-rich calcium silicate hydrate phases. The formation of the Cl-rich phases is enhanced by carbonation reactions and also by low temperatures (20 deg. C). The process may be important in retarding the migration of {sup 36}Cl from a repository for L/ILW. (authors)

  1. Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

    Science.gov (United States)

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward

    2013-01-01

    To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

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

    OpenAIRE

    Zenei Taira, Zenei; Ueda,Yukari

    2013-01-01

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

  3. Plant uptake of dual-labeled organic N biased by inorganic C uptake

    DEFF Research Database (Denmark)

    Rasmussen, Jim; Sauheitl, Leopold; Eriksen, Jørgen

    2010-01-01

    glycine or CO2-3 , but found no differences in uptake rates between these C-sources. The uptake of inorganic C to the shoot tissue was higher for maize grown in full light compared to shading, which indicates a passive uptake of inorganic C with water. We conclude that uptake of inorganic C produced...

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

    International Nuclear Information System (INIS)

    Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen

    2004-01-01

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

  5. Calcium regulation and Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Deepthi Rapaka

    2014-09-01

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

  6. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

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

    2010-01-01

    Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers....... Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon...

  7. Seasonal Variations in Mercury's Dayside Calcium Exosphere

    Science.gov (United States)

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

    2014-01-01

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

  8. Intracellular sphingosine releases calcium from lysosomes.

    Science.gov (United States)

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

    2015-11-27

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

  9. Uptake and recovery of americium and uranium by Anacystis biomass

    International Nuclear Information System (INIS)

    Liu, H.H.; Jiunntzong Wu

    1993-01-01

    The optimum conditions for the uptake of americium and uranium from wastewater solutions by Anacystis nidulans cells, and the recovery of these radionuclides were studied. The optimum pH range for both actinides was in the acidic region between 3.0 and 5.0. In a pH 3.5 solution with an algal biomass of 70 μg/mL, up to 95% of the Am and U were taken up by the cells. However, the uptake levels were lowered considerably when ethylene dinitrilotetraacetic acid (EDTA) or iron or calcium ions were present in the solutions. Most of the radionuclides taken up by the cells could also be desorbed by washing with salt solutions. Of nine salt solutions tested, ammonium carbonate was the most effective. Our experiments using algal biomass to remove radionuclides from wastewater showed that about 92% of americium and 85% of uranium in wastewater could be taken up by algal biomass, from which about 46% of the Am and 82% of the U originally present in the wastewater could be recovered by elution with a salt solution. 17 refs., 7 figs., 2 tabs

  10. Exopolysaccharides regulate calcium flow in cariogenic biofilms

    Science.gov (United States)

    Varenganayil, Muth M.; Decho, Alan W.

    2017-01-01

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

  11. Exopolysaccharides regulate calcium flow in cariogenic biofilms.

    Directory of Open Access Journals (Sweden)

    Monika Astasov-Frauenhoffer

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

  12. Cytosolic calcium homeostasis in fungi: Roles of plasma membrane transport and intracellular sequestration of calcium

    International Nuclear Information System (INIS)

    Miller, A.J.; Vogg, G.; Sanders, D.

    1990-01-01

    Cytosolic free calcium ([Ca 2+ ] c ) has been measured in the mycelial fungus Neurospora crassa with Ca 2+ - selective microelectrodes. The mean value of [Ca 2+ ] c is 92 ± 15 nM and it is insensitive to external pH values between 5.8 and 8.4. Simultaneous measurement of membrane potential enables the electrochemical potential difference for Ca 2+ across the plasma membrane to be estimated as about -60 kJmol -1 - a value that cannot be sustained either by a simple Ca 2+ - ATPase, or, in alkaline conditions, by straightforward H + /Ca 2+ exchange with a stoichiometric ratio of + /Ca 2+ . The authors propose that the most likely alternative mechanism of Ca 2+ efflux is ATP-driven H + /Ca 2+ exchange, with a stoichiometric ratio of at least 2 H + /Ca 2+ . The increase in [Ca 2+ ] c in the presence of CN - at pH 8.4 is compared with 45 Ca 2+ influx under the same conditions. The proportion of entering Ca 2+ remaining free in the cytosol is only 8 x 10 -5 , and since the concentration of available chelation sites on Ca 2+ binding proteins is unlikely to exceed 100 μM, a major role for the fungal vacuole in short-term Ca 2+ homeostasis is indicated. This notion is supported by the observation that cytosolic Ca 2+ homeostasis is disrupted by a protonophore, which rapidly abolishes the driving force for Ca 2+ uptake into fungal vacuoles

  13. Calcium transport into the cells of the sea urchin larva in relation to spicule formation.

    Science.gov (United States)

    Vidavsky, Netta; Addadi, Sefi; Schertel, Andreas; Ben-Ezra, David; Shpigel, Muki; Addadi, Lia; Weiner, Steve

    2016-10-24

    We investigated the manner in which the sea urchin larva takes up calcium from its body cavity into the primary mesenchymal cells (PMCs) that are responsible for spicule formation. We used the membrane-impermeable fluorescent dye calcein and alexa-dextran, with or without a calcium channel inhibitor, and imaged the larvae in vivo with selective-plane illumination microscopy. Both fluorescent molecules are taken up from the body cavity into the PMCs and ectoderm cells, where the two labels are predominantly colocalized in particles, whereas the calcium-binding calcein label is mainly excluded from the endoderm and is concentrated in the spicules. The presence of vesicles and vacuoles inside the PMCs that have openings through the plasma membrane directly to the body cavity was documented using high-resolution cryo-focused ion beam-SEM serial imaging. Some of the vesicles and vacuoles are interconnected to form large networks. We suggest that these vacuolar networks are involved in direct sea water uptake. We conclude that the calcium pathway from the body cavity into cells involves nonspecific endocytosis of sea water with its calcium.

  14. Trafficking of neuronal calcium channels

    Czech Academy of Sciences Publication Activity Database

    Weiss, Norbert; Zamponi, G. W.

    2017-01-01

    Roč. 1, č. 1 (2017), č. článku NS20160003. ISSN 2059-6553 R&D Projects: GA ČR GA15-13556S; GA MŠk 7AMB15FR015 Institutional support: RVO:61388963 Keywords : calcium channel * neuron * trafficing Subject RIV: ED - Physiology OBOR OECD: Physiology (including cytology) http://www.neuronalsignaling.org/content/1/1/NS20160003

  15. Constraining Calcium Production in Novae

    Science.gov (United States)

    Tiwari, Pranjal; C. Fry, C. Wrede Team; A. Chen, J. Liang Collaboration; S. Bishop, T. Faestermann, D. Seiler Collaboration; R. Hertenberger, H. Wirth Collaboration

    2017-09-01

    Calcium is an element that can be produced by thermonuclear reactions in the hottest classical novae. There are discrepancies between the abundance of Calcium observed in novae and expectations based on astrophysical models. Unbound states 1 MeV above the proton threshold affect the production of Calcium in nova models because they act as resonances in the 38 K(p , γ) 39 Ca reaction present. This work describes an experiment to measure the energies of the excited states of 39 Ca . We will bombard a thin target of 40 Ca with a beam of 22 MeV deuterons, resulting in tritons and 39Ca. We will use a Q3D magnetic spectrograph from the MLL in Garching, Germany to momenta analyze the tritons to observe the excitation energies of the resulting 39 Ca states. Simulations have been run to determine the optimal spectrograph settings. We decided to use a chemically stable target composed of CaF2 , doing so resulted in an extra contaminant, Fluorine, which is dealt with by measuring the background from a LiF target. These simulations have led to settings and targets that will result in the observation of the 39 Ca states of interest with minimal interference from contaminants. Preliminary results from this experiment will be presented. National Sciences and Engineering Research Council of Canada and U.S. National Science Foundation.

  16. DNA Uptake by Transformable Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lacks, Sanford A.

    1999-03-31

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  17. DNA UPTAKE BY TRANSFORMABLE BACTERIA

    Energy Technology Data Exchange (ETDEWEB)

    LACKS,S.A.

    1999-09-07

    The various processes of DNA uptake by cells can be categorized as: viral DNA entry, conjugation, or transformation. Within each category, a variety of mechanisms have been found. However, considerable similarities occur among the different mechanisms of conjugation and, especially, transformation. All of these natural mechanisms of DNA transfer are quite elaborate and involve multiple protein components, as the case may be, of the virus, the donor cell, and the recipient cell. The mechanisms of viral infection and conjugation will be discussed mainly with respect to their relevance to transformation.

  18. Mitochondrial and ER Calcium Uptake and Release Fluxes and their Interplay in Intact Nerve Cells

    Science.gov (United States)

    Friel, David D.

    Ionized free Ca ( Ca 2+) is a ubiquitous signaling ion that serves as the critical link between a variety of physiological stimuli and their intracellular effectors. Previous studies of reduced in vitro preparations have provided functional characterizations of various Ca 2+ channels, pumps and exchangers that regulate cellular Ca 2+ movements. However, little is known about the functional interplay between transporters that are expressed together in intact cells and orchestrate stimulus-evoked changes in [ Ca 2+]. This review summarizes recent progress in characterizing Ca 2+ transporters in sympathetic neurons, which provide an ideal model for studying Ca 2+ dynamics in neurons. Our results show how the functional interplay between Ca 2+ transport systems that are regulated by Ca 2+ in quantitatively differ-ent ways leads to emergent properties of Ca 2+ signaling that are expected to play a critical role in defining how Ca 2+ serves its role as a signaling ion.

  19. Elucidating the mechanisms of nickel compound uptake: A review of particulate and nano-nickel endocytosis and toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Alexandra; Costa, Max, E-mail: Max.Costa@nyumc.org

    2012-04-01

    Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses — most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanism of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties.

  20. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  1. The Role of Calcium in Osteoporosis

    Science.gov (United States)

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

    1991-01-01

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

  2. The Risks and Benefits of Calcium Supplementation

    Directory of Open Access Journals (Sweden)

    Chan Soo Shin

    2015-03-01

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

  3. Ocean uptake of carbon dioxide

    International Nuclear Information System (INIS)

    Peng, Tsung-Hung; Takahashi, Taro

    1993-01-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0 2 include carbon chemistry, distribution of alkalinity, pCO 2 and total concentration of dissolved C0 2 , sea-air pCO 2 difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0 2 uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0 2 from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0 2 fertilization is a potential candidate for such missing carbon sinks

  4. Alcohol enhances oxysterol-induced apoptosis in human endothelial cells by a calcium-dependent mechanism.

    Science.gov (United States)

    Spyridopoulos, I; Wischhusen, J; Rabenstein, B; Mayer, P; Axel, D I; Fröhlich, K U; Karsch, K R

    2001-03-01

    Controversy exists about the net effect of alcohol on atherogenesis. A protective effect is assumed, especially from the tannins and phenolic compounds in red wine, owing to their inhibition of low density lipoprotein (LDL) oxidation. However, increased atherogenesis occurs in subjects with moderate to heavy drinking habits. The purpose of this study was to investigate the influence of alcohol in combination with oxysterols on the endothelium. Cultured human arterial endothelial cells (HAECs) served as an in vitro model to test the cellular effects of various oxysterols. Oxysterols (7beta-hydroxycholesterol, 7-ketocholesterol, and cholesterol-5,6-epoxides), which are assumed to be the most toxic constituents of oxidized LDL, induced apoptosis in HAECs through calcium mobilization followed by activation of caspase-3. Ethanol, methanol, isopropanol, tert-butanol, and red wine all potentiated oxysterol-induced cell death up to 5-fold, paralleled by further induction of caspase-3. The alcohol effect occurred in a dose-dependent manner and reached a plateau at 0.05% concentration. Alcohol itself did not affect endothelial cell viability, nor did other solvents such as dimethyl sulfoxide mimic the alcohol effect. So far as the physiologically occurring oxysterols are concerned, this effect was apparent only for oxysterols oxidized at the steran ring. The possibility of alcohol facilitating the uptake of oxysterols into the cell was not supported by the data from an uptake study with radiolabeled compounds. Finally, alcohol in combination with oxysterols did cause a dramatic increase in cytosolic calcium influx. Blockage of calcium influx by the calcium channel blocker aurintricarboxylic acid or the calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid abrogated the alcohol-mediated enhancement of oxysterol toxicity. We describe for the first time a mechanistic concept explaining possible adverse effects of alcohol in conjunction with

  5. Removal of radioactive waste waters by calcium phosphate precipitation

    International Nuclear Information System (INIS)

    Raicevic, S.; Vukovic, Z.; Mandic, M.

    1997-01-01

    The kinetics of removal of radioactive strontium by coprecipitation and sorption with amorphous calcium phosphate (ACP) which transformed into stable crystalline hydroxyapatite (HA) were investigated. The advantage of phosphate precipitation is a possibility not only for removal of radioactive strontium but also for incorporation of a strontium ion into stable structure of HA. calcium phosphate was precipitated from highly saturated solution by fast reagent mixing. Kinetic experiments were performed using strontium nitrate solution labeled with 8 5 Sr. The amount of radionuclide uptake by the solid phase was determined radiometrically at different time intervals. It was found that ACP phase firmly retains coprecipitated impurities up to 150 min, of reaction time when partial rejection of strontium into the solution occurred. In sorption experiments after prolonged time of equilibrium the firm incorporation of 8 5 Sr stable crystalline structure of HA was detected. The incorporation of 8 5 Sr into crystalline HA was analysed in detail in the paper /S. Raicevic, et. al., J. Radioanal. Nucl. Chem., Articles, Vol. 204, No 2, 1996/ (author)

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

    Directory of Open Access Journals (Sweden)

    Bading Hilmar

    2007-07-01

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

  7. Evidence of arterial wall uptake of fluorodeoxyglucose on imaging can indicate recent or future cardiovascular events in high-risk patients

    International Nuclear Information System (INIS)

    Paulmier, B.; Khayat, R.; Duet, M.; Pierquet-Ghazzar, N.; Maunoury, C.; Sauvaget, E.; Faraggi, M.; Laissy, J.P.

    2007-01-01

    With this study, we sought to identify plaque inflammation as assessed by 18 FDG uptake on positron emission tomography (PET)/computed tomography (CT) as an independent cardiovascular risk factor in patients at high risk for cardiovascular events. We compared 31 consecutive cancer patients presenting with visually enhanced 18 FDG uptake in arterial walls on PET/CT (Group 1) to a selection of 34 matched cancer patients not showing arterial uptake (Group 2). All patients were followed for two years before and six months after PET/CT... Cardiovascular events were classified as older (>6 months before PET/CT) or recent ( 18 FDG uptake was computed on non-attenuation corrected data by a AW/L ratio: mean Arterial Wall uptake/Lung uptake in a normal area, and by SUV on corrected data. A calcium score (CS) was also calculated. 18 FDG uptake and CS were higher in Group 1 than Group 2 (both p = 0.02), and older and recent cardiovascular events were significantly more frequent in Group 1 than Group 2 (p = 0.001 and p = 0.03. respectively). Among the following parameters: number of conventional risk factor, calcium score and presence of 18 FDG uptake, only the latter was significantly related to the occurrence of a recent event by multivariate analysis (p = 0.02). Patients with elevated arterial 18 FDG uptake have a high risk of immediate or future cardiovascular events. Arterial 18 FDG uptake is an indicator of evolving atherosclerotic process and can indicate future cardiovascular events. (authors)

  8. Development of calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in cultured neocortical neurons visualized by cobalt staining

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1998-01-01

    The developmental expression of calcium (Ca2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors in cultured neocortical neurons was evaluated by using cobalt uptake, a histochemical method that identifies cells expressing Ca2+-permeable, non-N-methyl-D-aspartate...

  9. Increased muscle glucose uptake during contractions

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Galbo, Henrik; Richter, Erik

    1984-01-01

    We reinvestigated the prevailing concept that muscle contractions only elicit increased muscle glucose uptake in the presence of a so-called "permissive" concentration of insulin (Berger et al., Biochem. J. 146: 231-238, 1975; Vranic and Berger, Diabetes 28: 147-163, 1979). Hindquarters from rats...... in severe ketoacidosis were perfused with a perfusate containing insulin antiserum. After 60 min perfusion, electrical stimulation increased glucose uptake of the contracting muscles fivefold. Also, subsequent contractions increased glucose uptake in hindquarters from nondiabetic rats perfused for 1.5 h......-methylglucose uptake increased during contractions and glucose uptake was negative at rest and zero during contractions. An increase in muscle transport and uptake of glucose during contractions does not require the presence of insulin. Furthermore, glucose transport in contracting muscle may only increase if glycogen...

  10. Cell uptake survey of pegylated nanographene oxide.

    Science.gov (United States)

    Vila, M; Portolés, M T; Marques, P A A P; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Gonçalves, G; Cruz, S M A; Nieto, A; Vallet-Regi, M

    2012-11-23

    Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml(-1) pegylated GO solutions. GO uptake kinetics revealed differences in the agent's uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

  11. Cell uptake survey of pegylated nanographene oxide

    International Nuclear Information System (INIS)

    Vila, M; Nieto, A; Vallet-Regi, M; Portolés, M T; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Marques, P A A P; Gonçalves, G; Cruz, S M A

    2012-01-01

    Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml −1 pegylated GO solutions. GO uptake kinetics revealed differences in the agent’s uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy. (paper)

  12. Gastric gallium-67 uptake in gastritis

    International Nuclear Information System (INIS)

    Yeh, E.L.; Tisdale, P.L.; Zielonka, J.S.

    1983-01-01

    Even though Ga-67 imaging has been used widely in the diagnosis of malignant as well as inflammatory lesions, its uptake in the stomach has been reported in the literature mainly in gastric lymphoma and carcinoma. As shown in this case, intense gastric uptake of the radionuclide may be seen in common gastritis without malignancy. Perhaps the benign gastric uptake of Ga-67 deserves more emphasis

  13. Brain calcium - Role in temperature regulation.

    Science.gov (United States)

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

    1973-01-01

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

  14. 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...

  15. The total synthesis of calcium atorvastatin.

    Science.gov (United States)

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

    2016-02-21

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

  16. 21 CFR 184.1206 - Calcium iodate.

    Science.gov (United States)

    2010-04-01

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

  17. Hyaluronan and calcium carbonate hybrid nanoparticles for colorectal cancer chemotherapy

    Science.gov (United States)

    Bai, Jinghui; Xu, Jian; Zhao, Jian; Zhang, Rui

    2017-09-01

    A hybrid drug delivery system (DDS) composed of hyaluronan and calcium carbonate (CC) was developed. By taking advantage of the tumor-targeting ability of hyaluronan and the drug-loading property of CC, the well-formed hyaluronan-CC nanoparticles were able to serve as a DDS targeting colorectal cancer with a decent drug loading content, which is beneficial in the chemotherapy of colorectal cancer. In this study, hyaluronan-CC nanoparticles smaller than 100 nm were successfully developed to load the wide-range anti-cancer drug adriamycin (Adr) to construct hyaluronan-CC/Adr nanoparticles. On the other hand, we also found that hyaluronan-CC/Adr nanoparticles can possibly increase the uptake ratio of Adr into HT29 colorectal cancer cells when compared with hyaluronan-free nanoparticles (CC/Adr) via the CD44 receptor-mediated endocytosis via competitive uptake and in vivo imaging assays. Note that both in vitro (CCK-8 assay on HT29 cells) and in vivo (anti-cancer assay on HT-29 tumor-bearing nude mice model) experiments revealed that hyaluronan-CC/Adr nanoparticles exhibited stronger anti-cancer activity than free Adr or CC/Adr nanoparticles with minimized toxic side effects and preferable cancer-suppression potential.

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

    International Nuclear Information System (INIS)

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

    1984-01-01

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

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

    Science.gov (United States)

    Skulan, Joseph; DePaolo, Donald J.

    1999-01-01

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

  20. Radioiodine uptake by plants from soils

    International Nuclear Information System (INIS)

    Sabova, T.

    1976-01-01

    The uptake and accumulation of radioiodine by wheat, maize and peas from various types of soil have been studied. The uptake depends on the type of soil, on its content of organic matter and on the amount of fertilizer. Radioiodine is mainly accumulated in the roots. Accumulation in above-ground plant parts decreases in the following order: wheat, maize, peas. Uptake was highest from humus and clay soils and lowest from black and meadow soils. Application of chloride fertilizer or carrier iodine lead to an increase of radioiodine uptake in the whole plant. (author)

  1. Physiological FDG uptake in the palatine tonsils

    International Nuclear Information System (INIS)

    Kawabe, Joji; Okamura, Terue; Shakudo, Miyuki

    2001-01-01

    In clinical F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies of the head and neck region, remarkable symmetric tonsillar FDG uptake is sometimes observed. We determined the incidence and degree of tonsillar FDG uptake and investigated the significance of tonsillar FDG uptake. Between June 1998 and August 1998, we obtained informed consent from 17 patients who were scheduled to undergo a FDG-PET study for their own disease (11 men and 6 women; aged 22 to 77 yr) and who did not have head and neck disease to perform FDG-PET scanning of the head and neck region in addition to their target organs. The incidence and degree of tonsillar FDG uptake were determined. Remarkable tonsillar FDG uptake was found in 9 patients. The SUVs of these FDG uptakes ranged from 2.48 to 6.75, with a mean of 4.29±1.20 (SD). Tonsillar FDG uptakes in the remaining 8 patients were not remarkable, and their SUVs ranged from 1.93 to 3.31, with a mean of 2.46±0.45. Head and neck disease does not appear to have been responsible for the increase in tonsillar FDG uptake. Differences among tonsillar FDG uptake in these 17 patients without head and neck disease appear to reflect differences in activity of ''physiological'' inflammation of the palatine tonsils. (author)

  2. Radioiodine uptake in inactive pulmonary tuberculosis

    International Nuclear Information System (INIS)

    Bakheet, S.M.; Powe, J.; Al Suhaibani, H.; Hammami, M.M.; Bazarbashi, M.

    1999-01-01

    Radioiodine may accumulate at sites of inflammation or infection. We have seen such accumulation in six thyroid cancer patients with a history of previously treated pulmonary tuberculosis. We also review the causes of false-positive radioiodine uptake in lung infection/inflammation. Eight foci of radioiodine uptake were seen on six iodine-123 diagnostic scans. In three foci, the uptake was focal and indistinguishable from thyroid cancer pulmonary metastases from thyroid cancer. In the remaining foci, the uptake appeared nonsegmental, linear or lobar, suggesting a false-positive finding. The uptake was unchanged, variable in appearance or non-persistent on follow-up scans and less extensive than the fibrocystic changes seen on chest radiographs. In the two patients studied, thyroid hormone level did not affect the radioiodine lung uptake and there was congruent gallium-67 uptake. None of the patients had any evidence of thyroid cancer recurrence or of reactivation of tuberculosis and only two patients had chronic intermittent chest symptoms. Severe bronchiectasis, active tuberculosis, acute bronchitis, respiratory bronchiolitis, rheumatoid arthritis-associated lung disease and fungal infection such as Allescheria boydii and aspergillosis can lead to different patterns of radioiodine chest uptake mimicking pulmonary metastases. Pulmonary scarring secondary to tuberculosis may predispose to localized radioiodine accumulation even in the absence of clinically evident active infection. False-positive radioiodine uptake due to pulmonary infection/inflammation should be considered in thyroid cancer patients prior to the diagnosis of pulmonary metastases. (orig.)

  3. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  4. Effect of HeNe laser on calcium signals in sperm cells

    Science.gov (United States)

    Lubart, Rachel; Friedmann, Harry; Cohen, Natalie; Brietbart, Haim

    1998-12-01

    Irradiation of mouse spermatozoa by 630 nm HeNe laser was found to enhance calcium transport in these cells. The change in Ca transport was investigated through two approaches, the first employing the fluorescent Ca indicator, Fluo-3 AM and a fluorescence microscopic system, and the second the radiolabeled Ca uptake. In both approaches the effect of light on Ca transport was abrogated in the absence of Ca during the irradiation time, indicating that the effect of light is Ca-dependent. The stimulatory effect of light on Ca uptake was inhibited by treatment with catalase, suggesting H2O2 to be involved in light stimulated Ca2+ uptake. The stimulatory effect of light on Ca uptake was abolished in the presence of a voltage-dependent Ca-channel inhibitor, nifedipine, indicating the involvement of a plasma membrane, voltage- dependent Ca-channel. In contrast, addition of nifedipine prior to the HeNe laser irradiation did not affect the light-induced rise in intracellular Ca levels, as measured with Fluo-3 loaded sperm cells. Therefore, it can be concluded that this Ca influx occurs via a voltage- insensitive Ca-channel. The stimulatory effect of light on Ca uptake was almost completely abolished by the mitochondrial uncoupler FCCP. These data imply that light affects the mitochondrial Ca transport mechanisms. It is well known that Ca influx from an extracellular environment is an essential component of a signaling cascade leading to fertilization.

  5. Regulation of cardiomyocyte autophagy by calcium.

    Science.gov (United States)

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

    2016-04-15

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

  6. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

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

  7. Diuretics and disorders of calcium homeostasis.

    Science.gov (United States)

    Grieff, Marvin; Bushinsky, David A

    2011-11-01

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

  8. Trace mineral interactions during elevated calcium consumption

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  9. [Calcium hypothesis of Alzheimer disease].

    Science.gov (United States)

    Riazantseva, M A; Mozhaeva, G N; Kaznacheeva, E V

    2012-01-01

    Alzheimer's disease is the most common neurodegenerative disorder characterized by progressive memory and cognitive abilities loss. The etiology of Alzheimer's disease is poorly understood. In this regard, there is no effective treatment for the disease. Various hypotheses to explain the nature of the pathology of Alzheimer's disease led to the development of appropriate therapeutics. Despite of decades of research and clinical trials available therapeutics, at best, can only slow down the progression of the disease, but cannot cure it. This review dedicated to the one of modern hypotheses of Alzheimer's disease pathogenesis implied the impairment of calcium homeostasis as a key event for the development of neurodegenerative processes.

  10. Calcium

    Science.gov (United States)

    ... of new bone. People with lactose intolerance cannot digest this natural sugar found in milk and experience ... Disclaimer | FOIA | Información en español Download free Acrobat Reader Term Selected: Select the term below that you' ...

  11. Calcium and Strontium in Swedish Waters and Fish, and Accumulation of Strontium-90

    Energy Technology Data Exchange (ETDEWEB)

    Agnedal, P O

    1966-04-15

    The purpose of this study has been to investigate the correlation between calcium and strontium in fish in relation to the concentration of these elements in the water. An investigation of the uptake of strontium-90 has also been made and permissible levels of strontium-90 in the water is calculated based upon the uptake in fish muscle tissues. Lakes with calcium concentrations between 2 - 63 mg/l have been studied and samples from the Baltic coastal water are also included. Three fish species are studied, viz. pike (Esox lucius (L.)), perch (Perca fluviatilis (L.)) and roach (Leuciscus rutilus (L.)). Bones, muscle tissues and skin + scales have been analysed. Strontium-90 measurements have been made showing an increase in both water and fish. Calculations show that in water with about 2 mg Ca/l a 10-fold increase of the existing strontium-90 level might give strontium-90 concentrations in fish muscle tissues close to what is permissible. In lakes with calcium concentrations 20 - 40 mg/l the permissible levels for drinking water will be exceeded before the fish consumption would have to be restricted.

  12. Calcium and Strontium in Swedish Waters and Fish, and Accumulation of Strontium-90

    International Nuclear Information System (INIS)

    Agnedal, P.O.

    1966-04-01

    The purpose of this study has been to investigate the correlation between calcium and strontium in fish in relation to the concentration of these elements in the water. An investigation of the uptake of strontium-90 has also been made and permissible levels of strontium-90 in the water is calculated based upon the uptake in fish muscle tissues. Lakes with calcium concentrations between 2 - 63 mg/l have been studied and samples from the Baltic coastal water are also included. Three fish species are studied, viz. pike (Esox lucius (L.)), perch (Perca fluviatilis (L.)) and roach (Leuciscus rutilus (L.)). Bones, muscle tissues and skin + scales have been analysed. Strontium-90 measurements have been made showing an increase in both water and fish. Calculations show that in water with about 2 mg Ca/l a 10-fold increase of the existing strontium-90 level might give strontium-90 concentrations in fish muscle tissues close to what is permissible. In lakes with calcium concentrations 20 - 40 mg/l the permissible levels for drinking water will be exceeded before the fish consumption would have to be restricted

  13. Regulation of myosin light chain kinase during insulin-stimulated glucose uptake in 3T3-L1 adipocytes.

    Directory of Open Access Journals (Sweden)

    Shelly Woody

    Full Text Available Myosin II (MyoII is required for insulin-responsive glucose transporter 4 (GLUT4-mediated glucose uptake in 3T3-L1 adipocytes. Our previous studies have shown that insulin signaling stimulates phosphorylation of the regulatory light chain (RLC of MyoIIA via myosin light chain kinase (MLCK. The experiments described here delineate upstream regulators of MLCK during insulin-stimulated glucose uptake. Since 3T3-L1 adipocytes express two MyoII isoforms, we wanted to determine which isoform was required for insulin-stimulated glucose uptake. Using a siRNA approach, we demonstrate that a 60% decrease in MyoIIA protein expression resulted in a 40% inhibition of insulin-stimulated glucose uptake. We also show that insulin signaling stimulates the phosphorylation of MLCK. We further show that MLCK can be activated by calcium as well as signaling pathways. We demonstrate that adipocytes treated with the calcium chelating agent, 1,2-b (iso-aminophenoxy ethane-N,N,N',N'-tetra acetic acid, (BAPTA (in the presence of insulin impaired the insulin-induced phosphorylation of MLCK by 52% and the RLC of MyoIIA by 45% as well as impairing the recruitment of MyoIIA to the plasma membrane when compared to cells treated with insulin alone. We further show that the calcium ionophore, A23187 alone stimulated the phosphorylation of MLCK and the RLC associated with MyoIIA to the same extent as insulin. To identify signaling pathways that might regulate MLCK, we examined ERK and CaMKII. Inhibition of ERK2 impaired phosphorylation of MLCK and insulin-stimulated glucose uptake. In contrast, while inhibition of CaMKII did inhibit phosphorylation of the RLC associated with MyoIIA, inhibition of CAMKIIδ did not impair MLCK phosphorylation or translocation to the plasma membrane or glucose uptake. Collectively, our results are the first to delineate a role for calcium and ERK in the activation of MLCK and thus MyoIIA during insulin-stimulated glucose uptake in 3T3-L1 adipocytes.

  14. Effects of dissolved metals and other hydrominerals on in vivo intestinal zinc uptake in freshwater rainbow trout

    International Nuclear Information System (INIS)

    Glover, Chris N.; Hogstrand, Christer

    2003-01-01

    For aquatic organisms, zinc is both an essential nutrient and an environmental contaminant. The intestine is potentially the most important route of zinc absorption, yet little is known regarding this uptake pathway for zinc in fish. A recently developed in vivo perfusion system was used to investigate the effect of luminal composition upon intestinal zinc uptake in freshwater rainbow trout (Oncorhynchus mykiss). Perfusate cadmium and copper had specific, yet distinct, antagonistic effects upon lumen to tissue zinc movement. Copper significantly reduced the proportion of zinc taken up from the perfusate, and concomitantly limited the passage of zinc into the circulation and beyond. Conversely, cadmium decreased subepithelial zinc accumulation, with rates falling to 29 nmol g -1 h -1 from the control (zinc alone) values of 53 nmol g -1 h -1 . Calcium had a similar action to copper, also reducing post-intestinal zinc accumulation from 0.06 to 0.02 nmol g -1 h -1 , an effect attributed to interactions between calcium and the zinc uptake pathway. In addition to these effects, luminal composition also had a marked influence upon epithelial response to zinc. Calcium, copper and magnesium all greatly reduced zinc-induced mucus secretion. Cadmium, a toxic metal, significantly increased mucus secretion. It is proposed that these modifications were related to the essentiality of each element, and their potential mechanisms of uptake. Despite changes at the epithelium, the post-epithelial accumulation of zinc was dependent mainly upon the nature of the competing cation. Intestinal saline ion substitution experiments suggested a potential link of potassium ion efflux to zinc uptake. The effect of pH buffering of luminal solutions was also investigated

  15. Bone uptake of Tc-99m MIBI in patients with hyperparathyroidism

    International Nuclear Information System (INIS)

    Zhao, Yunyun; Wang, Qian

    2014-01-01

    The study aimed to investigate the incidence of bone uptake of tracer on Tc-99m MIBI imaging and explore its influencing factors and significance for diagnosis of metabolic bone disease (MBD) in patients with hyperparathyroidism (HPT). Seventy-nine consecutive patients with histopathologically confirmed HPT (63 primary and 16 secondary) who had preoperative Tc-99m MIBI imaging were retrospectively evaluated. Serum calcium (Ca), phosphorus (P), and intact parathyroid hormone (iPTH) were measured for all patients, and serum alkaline phosphatase (ALP) was measured for 62 patients. Of the 79 patients, 50 underwent bone mineral density (BMD) examination and 30 underwent bone scintigraphy. The incidence and characteristics of abnormal bone uptake of MIBI were recorded. Mann-Whitney test was performed to determine if serum iPTH, Ca, P, ALP, and BMD were different between the patients with and without MIBI bone uptake. Logistic regression analysis was used to analyze the factors that influence the bone uptake of MIBI. The concordance rate between Tc-99m MIBI imaging and bone scintigraphy in delineating MBD was calculated. Tc-99m MIBI imaging disclosed the abnormal bone uptake of tracer in 22 (27.8%) patients. Of them, 19 showed diffusely increased activity in skeleton, 2 showed focal uptake in brown tumors, and one showed both above patterns. Patients with bone uptake MIBI had higher level of serum iPTH (Z=-4.34, P < 0.001) and ALP (Z=-3.50, P < 0.001) than those without bone uptake. Logistic regression analysis also showed that bone uptake of MIBI was correlated with serum iPTH (OR=4.42, P < 0.001) and ALP (OR=3.21, P=0.002). Among the 30 patients that underwent bone scintigraphy, 76.7% patients showed signs of MBD, and the concordance rate between Tc-99m MIBI imaging and bone scintigraphy was 60% for detecting MBD. Bone uptake of MIBI in patients with HPT is commonly related to a high level of iPTH and ALP; it probably reflects an active stage of MBD, and it should be

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  20. Normal cerebral FDG uptake during childhood

    International Nuclear Information System (INIS)

    London, Kevin; Howman-Giles, Robert

    2014-01-01

    Current understanding of cerebral FDG uptake during childhood originates from a small number of studies in patients with neurological abnormalities. Our aim was to describe cerebral FDG uptake in a dataset of FDG PET scans in children more likely to represent a normal population. We reviewed cerebral FDG PET scans in children up to 16 years of age with suspected/proven extracranial malignancies and the following exclusions: central nervous system metastases, previous malignancies, previous chemotherapy or radiotherapy, development of cerebral metastases during therapy, neurological conditions, taking antiepileptic medication or medications likely to interfere with cerebral metabolism, and general anaesthesia within 24 h. White matter, basal ganglia, thalamus and the cerebellar cortex were analysed using regional SUV max , and the cerebral cortex, basal ganglia, thalamus and cerebellum were analysed using a regional relative uptake analysis in comparison to maximal cortical uptake. Scans from 30 patients (age range 11 months to 16 years, mean age 10 years 5 months) were included. All regions showed increasing SUV max with age. The parietal, occipital, lateral temporal and medial temporal lobes showed lower rates of increasing FDG uptake causing changing patterns of regional FDG uptake during childhood. The cortical regions showing the most intense uptake in early childhood were the parietal and occipital lobes. At approximately 7 years of age these regions had relatively less uptake than the frontal lobes and at approximately 10 years of age these regions had relatively less uptake than the thalamus. Relative FDG uptake in the brain has not reached an adult pattern by 1 year of age, but continues to change up to 16 years of age. The changing pattern is due to different regional rates of increasing cortical FDG uptake, which is less rapid in the parietal, occipital and temporal lobes than in the frontal lobes. (orig.)

  1. Normal cerebral FDG uptake during childhood

    Energy Technology Data Exchange (ETDEWEB)

    London, Kevin [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Discipline of Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia); Howman-Giles, Robert [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Disciplines of Imaging and Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia)

    2014-04-15

    Current understanding of cerebral FDG uptake during childhood originates from a small number of studies in patients with neurological abnormalities. Our aim was to describe cerebral FDG uptake in a dataset of FDG PET scans in children more likely to represent a normal population. We reviewed cerebral FDG PET scans in children up to 16 years of age with suspected/proven extracranial malignancies and the following exclusions: central nervous system metastases, previous malignancies, previous chemotherapy or radiotherapy, development of cerebral metastases during therapy, neurological conditions, taking antiepileptic medication or medications likely to interfere with cerebral metabolism, and general anaesthesia within 24 h. White matter, basal ganglia, thalamus and the cerebellar cortex were analysed using regional SUV{sub max}, and the cerebral cortex, basal ganglia, thalamus and cerebellum were analysed using a regional relative uptake analysis in comparison to maximal cortical uptake. Scans from 30 patients (age range 11 months to 16 years, mean age 10 years 5 months) were included. All regions showed increasing SUV{sub max} with age. The parietal, occipital, lateral temporal and medial temporal lobes showed lower rates of increasing FDG uptake causing changing patterns of regional FDG uptake during childhood. The cortical regions showing the most intense uptake in early childhood were the parietal and occipital lobes. At approximately 7 years of age these regions had relatively less uptake than the frontal lobes and at approximately 10 years of age these regions had relatively less uptake than the thalamus. Relative FDG uptake in the brain has not reached an adult pattern by 1 year of age, but continues to change up to 16 years of age. The changing pattern is due to different regional rates of increasing cortical FDG uptake, which is less rapid in the parietal, occipital and temporal lobes than in the frontal lobes. (orig.)

  2. Research applications of calcium-47

    International Nuclear Information System (INIS)

    1962-01-01

    The possibility of using the isotope calcium-47 for calcium metabolism investigation was discussed. It seemed particularly suited for this purpose since it has a half-life of only 4.7 days; it is, moreover, a strong gamma-emitter which permits easy detection of very small quantities from outside the body. It was, however, produced on an experimental basis only and at a price of US $1400 per mC which was beyond the financial possibilities of almost any medical research institution or hospital. In view of IAEA's mandate to promote isotope research in the fields of radiobiology and medicine the participants asked the Agency to carry out a programme of encouraging research that might lead to cheaper methods of producing this isotope and of assisting in its practical applications in diagnosis and clinical research. The Agency took up this suggestion and the way it has pursued the project might be considered characteristic of its methods of dealing with such problems on an international scale

  3. Research applications of calcium-47

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1962-04-15

    The possibility of using the isotope calcium-47 for calcium metabolism investigation was discussed. It seemed particularly suited for this purpose since it has a half-life of only 4.7 days; it is, moreover, a strong gamma-emitter which permits easy detection of very small quantities from outside the body. It was, however, produced on an experimental basis only and at a price of US $1400 per mC which was beyond the financial possibilities of almost any medical research institution or hospital. In view of IAEA's mandate to promote isotope research in the fields of radiobiology and medicine the participants asked the Agency to carry out a programme of encouraging research that might lead to cheaper methods of producing this isotope and of assisting in its practical applications in diagnosis and clinical research. The Agency took up this suggestion and the way it has pursued the project might be considered characteristic of its methods of dealing with such problems on an international scale

  4. Physiological controls on seawater uptake and calcification in the benthic foraminifer Ammonia tepida

    Directory of Open Access Journals (Sweden)

    G. Nehrke

    2009-11-01

    Full Text Available To analyze the relation between seawater uptake and calcification, we incubated juveniles of the benthic foraminifer Ammonia tepida with various fluorescent probes and visualised them afterwards with confocal laser scanning microscopy. Vesicle membranes, Ca ions and vacuole fluids were followed with various tracers and showed for the first time that endocytosis of seawater is part of the calcification process in Ammonia tepida. Data on the intracellular Ca ion cycling allowed for calculating a preliminary cellular Ca budget during foraminiferal calcification. This showed that the free calcium involved in the production of a new chamber cannot be sufficient and suggests that foraminifera may precipitate their calcite from an amorphous precursor.

  5. An experimental study of mandibular fracture wound healing in the calcium deficient rat

    International Nuclear Information System (INIS)

    Lee, Sang Hoon; Wang, Eui Hwan; Lee, Sang Rae

    1997-01-01

    The purpose of this study was to investigate effects of osteoporosis on fracture wound healing in the calcium deficient rat. To research the experiment some ten-week old Wistar strain rats with approximately 300 gms weight were selected. Then, the rats were divided into two groups : Normal diet group (rats given a normal diet before and after bone fracture) and Low calcium diet group (rats given a low calcium diet before and after bone fracture). Both groups had been provided with each diet for three weeks. When the rats became thirteen weeks old, the mandibular angle of rats in both groups was artificially fractured for test. The healing of fracture wounds was reviewed by using soft x-ray radiography and 99m Tc-MDP bone scan and also histopathologic examination. The obtained results were as follows : 1. The radiolucency of the fracture site for the Normal diet group started to decrease from the 14th day since the experiment was made, while the Low calcium diet group began decrease in the radiolucency from the 21st day of the experiment . The radiolucency for the normal diet group disappeared at the 42nd day, but one for the Low calcium diet group disappeared at the 56th day of the experiment. 2. The highest uptake rate of 99m Tc-MDP stood at the 14th day of the experiment in the Normal diet group and the Low calcium diet group's maximum rate was recorded at the 21st day of the experiment. These both groups were gradually experiencing decrease in the uptake rate as the experiment time was going on. However, the uptake rate in the Low calcium diet group was lower than one in the Normal diet group. 3. For the Normal diet group, the newly formed trabecular, which were similar to one of the surrounding bone, were seen at the 42nd day of the experiment. On the other hand, the Low claium diet group showed at the 56th day of the experiment that the osteoporotic findings looked weak, irregular trabecular, and also large bone marrow space were observed clearly. As a result

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

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  7. An experimental study of extraction wound healing in the calcium deficient rat and maxillofacial

    Energy Technology Data Exchange (ETDEWEB)

    You, Young Sun; Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kyung Hee University, (Korea, Republic of)

    1996-08-15

    The purpose of this study was to investigate effects of osteoporosis on extraction wound healing in the calcium deficient rat. In order to carry out this study, ten-week old Wistar strain rats weighing about 300 gms were selected. When the ras reached thirteen-week old, rat's mandibular first molar were removed. The rats were then divided into three groups : Group 1(rats given a normal diet both before and after tooth extraction), Group 2(rats given a low calcium diet for three weeks before tooth extraction and a normal diet after tooth extraction), and Group 3(rats given a low calcium diet for three weeks before and after tooth extraction). The healing of extraction wounds, as assessed by microradiography, autoradiography, and histopathologic examination, were compared among these three groups. The obtained results were as follows : 1. In Group 1, newly formed bone and active uptake of 45 Ca around extraction wound were noted on the 3rd and the 7th day. On the 14th and the 21st day, the extraction wounds of this group showed the bone trabecular formation and active 45 Ca uptake in the extraction wound and alveolar crest. The more prominent bone trabuculae with a less uptake of 45 Ca were noted on the 42nd day. 2. In Group 2, newly formed bone and thinning of alveolar bone trabeculae with more extensive uptake of 45 Ca than that in Group 1 were noted on the 3rd and the 7th day. On the 14th day, bone trabeculae were less thicker than that in Group 1. the prominent bone trabeculae in the extraction wounds and alveolar crest were noted on the 21st and the 42nd days. 3. In Group 3, newly formed bone was noted on the 3rd and the 7th day, Alveolar bone trabeculae and uptake of 45 Ca were similar to that in Group 2. On the 14th and 21st day, bone trabeculae were less thicker than that in Group 2 and group 3. the osteoporotic change with active uptake of 45 Ca was markedly noted on the 42nd day.

  8. An experimental study of extraction wound healing in the calcium deficient rat and maxillofacial

    International Nuclear Information System (INIS)

    You, Young Sun; Hwang, Eui Hwan; Lee, Sang Rae

    1996-01-01

    The purpose of this study was to investigate effects of osteoporosis on extraction wound healing in the calcium deficient rat. In order to carry out this study, ten-week old Wistar strain rats weighing about 300 gms were selected. When the ras reached thirteen-week old, rat's mandibular first molar were removed. The rats were then divided into three groups : Group 1(rats given a normal diet both before and after tooth extraction), Group 2(rats given a low calcium diet for three weeks before tooth extraction and a normal diet after tooth extraction), and Group 3(rats given a low calcium diet for three weeks before and after tooth extraction). The healing of extraction wounds, as assessed by microradiography, autoradiography, and histopathologic examination, were compared among these three groups. The obtained results were as follows : 1. In Group 1, newly formed bone and active uptake of 45 Ca around extraction wound were noted on the 3rd and the 7th day. On the 14th and the 21st day, the extraction wounds of this group showed the bone trabecular formation and active 45 Ca uptake in the extraction wound and alveolar crest. The more prominent bone trabuculae with a less uptake of 45 Ca were noted on the 42nd day. 2. In Group 2, newly formed bone and thinning of alveolar bone trabeculae with more extensive uptake of 45 Ca than that in Group 1 were noted on the 3rd and the 7th day. On the 14th day, bone trabeculae were less thicker than that in Group 1. the prominent bone trabeculae in the extraction wounds and alveolar crest were noted on the 21st and the 42nd days. 3. In Group 3, newly formed bone was noted on the 3rd and the 7th day, Alveolar bone trabeculae and uptake of 45 Ca were similar to that in Group 2. On the 14th and 21st day, bone trabeculae were less thicker than that in Group 2 and group 3. the osteoporotic change with active uptake of 45 Ca was markedly noted on the 42nd day.

  9. The relationship between transpiration and nutrient uptake in wheat changes under elevated atmospheric CO2.

    Science.gov (United States)

    Houshmandfar, Alireza; Fitzgerald, Glenn J; O'Leary, Garry; Tausz-Posch, Sabine; Fletcher, Andrew; Tausz, Michael

    2017-12-04

    The impact of elevated [CO 2 ] (e[CO 2 ]) on crops often includes a decrease in their nutrient concentrations where reduced transpiration-driven mass flow of nutrients has been suggested to play a role. We used two independent approaches, a free-air CO 2 enrichment (FACE) experiment in the South Eastern wheat belt of Australia and a simulation study employing the agricultural production systems simulator (APSIM), to show that transpiration (mm) and nutrient uptake (g m -2 ) of nitrogen (N), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg) and manganese (Mn) in wheat are correlated under e[CO 2 ], but that nutrient uptake per unit water transpired is higher under e[CO 2 ] than under ambient [CO 2 ] (a[CO 2 ]). This result suggests that transpiration-driven mass flow of nutrients contributes to decreases in nutrient concentrations under e[CO 2 ], but cannot solely explain the overall decline. © 2017 Scandinavian Plant Physiology Society.

  10. Uptake of organic nitrogen by plants

    Science.gov (United States)

    Torgny Nasholm; Knut Kielland; Ulrika. Ganeteg

    2009-01-01

    Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for...

  11. Gallium 67 uptake in thymic rebound

    International Nuclear Information System (INIS)

    Hurst, R.; Sabio, H.; Teates, C.D.

    1988-01-01

    We have reported a case of localized thymic enlargement and uptake of gallium 67 in a child who had received antineoplastic chemotherapy. The enlarged thymus showed normal histology, a picture consistent with thymic rebound after nonspecific stress. This case further demonstrates the need to consider thymic rebound as a cause of gallium 67 uptake in children with neoplastic diseases

  12. Uptake of inorganic contaminants by pteridophytes

    International Nuclear Information System (INIS)

    Zheng Jiemin; Chen Ziyuan; Tang Shirong; Guangzhou Univ., Guangzhou; Ding Bingyang

    2005-01-01

    The review covers results at home and abroad in terms of uptake of inorganic contaminants by pteridophytes, and suggests pteridophytes' significance in phytoremediation; the mechanisms related to uptake of inorganic contaminants by pteridophytes and some methods and means used for research on the mechanism are also introduced; the authors' viewpoints on future development trends are presented in this paper. (authors)

  13. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Wafar, S.; Rajkumar, R.

    that for nitrate [2.8 nmol. ( mu chl-a)./1h/1] and urea [0.37 nmol. ( mu chl-a)./1h/1]. Half-saturation constants for uptake of the three nitrogen compounds were in the range of 10-15 mu mol.l/1. Generally, uptake of any one nitrogen substrate appears to be inhibit...

  14. Radio-active iodine uptake in vitiligo

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.; Shankar, V.; Chaudhary, S.; Bhatia, K.K.; Mehta, L.K.; Arora, D.R. (Medical College and Hospital, Rohtak-124001 (India))

    1990-01-01

    Vitiligo and thyroid disease are commonly associated disorders. Twenty-two clinically euthyroid vitiligo patients were studied for functional assessment of thyroid by radioactive iodine uptake assay. Half of them showed abnormal uptake values at 24 hours. Of these patients, 90% had lower values indicating a tendency towards developing hypothyroid state. Subclinical thyroid dysfunction in vitiligo appears to be an adaptive change. (author).

  15. Radio-active iodine uptake in vitiligo

    International Nuclear Information System (INIS)

    Kumar, V.; Shankar, V.; Chaudhary, S.; Bhatia, K.K.; Mehta, L.K.; Arora, D.R.

    1990-01-01

    Vitiligo and thyroid disease are commonly associated disorders. Twenty-two clinically euthyroid vitiligo patients were studied for functional assessment of thyroid by radioactive iodine uptake assay. Half of them showed abnormal uptake values at 24 hours. Of these patients, 90% had lower values indicating a tendency towards developing hypothyroid state. Subclinical thyroid dysfunction in vitiligo appears to be an adaptive change. (author)

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

    Science.gov (United States)

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

    2017-09-15

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

  17. 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...

  18. CALCIUM AND THE PREVENTION OF COLON CANCER

    NARCIS (Netherlands)

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

    1991-01-01

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

  19. Comparison of Serum Calcium and Magnesium Between ...

    African Journals Online (AJOL)

    Background: Evidence suggests the involvement of calcium and magnesium metabolism in the pathophysiology of preeclampsia. However, findings from studies are heterogenous and inconsistent. Aim: The study aimed to compare the total serum calcium and magnesium levels in preeclamptic women with that of ...

  20. Fast kinetics of calcium dissociation from calsequestrin

    Directory of Open Access Journals (Sweden)

    MARIANELA BELTRÁN

    2006-01-01

    Full Text Available We measured the kinetics of calcium dissociation from calsequestrin in solution or forming part of isolated junctional sarcoplasmic reticulum membranes by mixing calsequestrin equilibrated with calcium with calcium-free solutions in a stopped-flow system. In parallel, we measured the kinetics of the intrinsic fluorescence changes that take place following calcium dissociation from calsequestrin. We found that at 25ºC calcium dissociation was 10-fold faster for calsequestrin attached to junctional membranes (k = 109 s-1 than in solution. These results imply that calcium dissociation from calsequestrin in vivo is not rate limiting during excitation-contraction coupling. In addition, we found that the intrinsic fluorescence decrease for calsequestrin in solution or forming part of junctional membranes was significantly slower than the rates of calcium dissociation. The kinetics of intrinsic fluorescence changes had two components for calsequestrin associated to junctional membranes and only one for calsequestrin in solution; the faster component was 8-fold faster (k = 54.1 s-1 than the slower component (k = 6.9 s-1, which had the same k value as for calsequestrin in solution. These combined results suggest that the presence of calsequestrin at high concentrations in a restricted space, such as when bound to the junctional membrane, accelerates calcium dissociation and the resulting structural changes, presumably as a result of cooperative molecular interactions.

  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. In vivo calcium metabolism by IRMS

    Science.gov (United States)

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

  3. 21 CFR 172.715 - Calcium lignosulfonate.

    Science.gov (United States)

    2010-04-01

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

  4. Sensory analysis of calcium-biofortified lettuce

    Science.gov (United States)

    Vegetables represent an attractive means of providing increased calcium nutrition to the public. In this study, it was demonstrated that lettuce expressing the deregulated Arabidopsis H(+)/Ca(2+) transporter sCAX1 (cation exchanger 1) contained 25-32% more calcium than controls. These biofortified l...

  5. 21 CFR 184.1187 - Calcium alginate.

    Science.gov (United States)

    2010-04-01

    ... ingredient is used in food only within the following specific limitations: Category of food Maximum level of... other food categories 0.3 Do. (d) Prior sanctions for calcium alginate different from the uses... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food...

  6. Calcium supplementation in osteoporosis: useful or harmful?

    Science.gov (United States)

    Chiodini, Iacopo; Bolland, Mark J

    2018-04-01

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

  7. 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.

  8. Oligofructose stimulates calcium absorption in adolescents

    NARCIS (Netherlands)

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

    1999-01-01

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

  9. Rates of calcium carbonate removal from soils.

    NARCIS (Netherlands)

    Breemen, van N.; Protz, R.

    1988-01-01

    Mean annual rates of calcium carbonate removal from soils in a subarctic climate estimated from data on two chronosequences of calcareous storm ridges, appeared to be relatively constant through time. Concentrations of dissolved calcium carbonate in the soil solution in the study sites calculated

  10. Uptake and transport of chromium in plants

    International Nuclear Information System (INIS)

    Ramachandran, V.; D'souza, T.J.; Mistry, K.B.

    1980-01-01

    The uptake of chromium, an important soil and water pollutant, by five different plant species was examined in nutrient culture experiments using chromium-51 as a tracer. The concentration in aerial tissues of both trivalent and hexavalent forms of chromium was the greatest in peas followed by beans, tomato and the cereals over identical uptake periods. The uptake of 51 Cr 3+ was, in general, greater than 51 CrO 4 2- . Studies with bean plants indicated that shoot uptake of both forms of chromium decreased with increasing pH and salt concentration of the external solution. Concentrations of 10 -4 M and 10 -5 M DNP inhibited 51 Cr uptake by bean shoots. (author)

  11. Insulin resistance and maximal oxygen uptake

    DEFF Research Database (Denmark)

    Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

    2003-01-01

    BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

  12. Incidental Diagnosis of Carcinoma of the Bladder Due to Uptake of {sup 99m}Tc-MDP

    Energy Technology Data Exchange (ETDEWEB)

    Damle, Nishikant A; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar; Subbarao, Kiran; Singh, Prabhjot [All India Institute of Medical Sciences, New Delhi (India); Mishra, Rohini; Das, Nitendra Lal; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar [B. L. Kapur Memorial Hospital, New Delhi (India)

    2012-06-15

    A bone scan was per-formed using 740 MBq (29 mCi) {sup 99}mTc-MDP. Whole-body planar images were acquired 3 h after injection (Fig. 1). Soft tissue uptake of {sup 99}mTc-MDP is described in various benign and malignant conditions. It is known to accumulate in adenocarcinoma of lung, primary breast cancer, and colonic carcinoma among others. The postulated causes of {sup 99}mTc-MDP uptake in extraosseous neoplasms are numerous and include tumor vascularity, inflammation, local pH factors, altered calcium metabolism, hormonal influences and cell wall damage. Our case shows that TCC of the bladder was incidentally diagnosed due to MDP uptake in multiple bladder polyps detected on a bone scan done for low backache in an 80-year-old man.

  13. Ratio of late to early radionuclide uptake: a method for distinguishing osteoporosis from osteomalacia in animal models

    International Nuclear Information System (INIS)

    Wilson, J.S.; Genant, H.K.; Hattner, R.S.; Hoffer, P.B.

    1978-01-01

    The ratio of late to early uptake of several radionuclides was examined as a method for distinguishing states of abnormal bone metabolism. Nutritional osteoporosis (secondary hyperparathyroidism) and osteomalacia were produced in young rats and compared to a control group. The ratio of early (3 to 6 hrs) to late (4 to 6 days) uptake of barium-131, nitrate, indium-111 EDTMP, and lead-203 were studied, as was that of strontium-85 chloride, a calcium analogue. Ratios of late to early uptake were found to distinguish osteomalacia from osteoporosis in the models when strontium-85 or barium-131 were used. Barium-131 may be a clinically useful alternative to strontium-85 in the evaluation of metabolic bone disease due to its shorter half-life and lower radiation dose

  14. Uptake and expression of bacterial and cyanobacterial genes by isolated cucumber etioplasts

    Energy Technology Data Exchange (ETDEWEB)

    Daniell, H.; McFadden, B.A.

    1987-09-01

    The uptake and expression by plastids isolated from dark-grown cucumber cotyledons (etioplasts) of two pUC derivatives, pCS75 and pUC9-CM, respectively carrying genes for the large and small subunits of ribulose bisphosphate carboxylase/oxygenase of Anacystis nidulans or chloramphenicol acetyltransferase, is reported. Untreated etioplasts take up only 3% as much DNA as that taken up by EDTA-washed etioplasts after 2 hr of incubation with nick-translated (/sup 32/P)-pCS75. The presence or absence of light does not affect DNA uptake, binding, or breakdown by etioplasts. Calcium or magnesium ions inhibit DNA uptake by 86% but enhance binding and breakdown of donor DNA by EDTA-treated etioplasts. Uncouplers that abolish membrane potential, transmembrane proton gradient, or both do not affect DNA uptake, binding, or breakdown by etioplasts. However, both DNA uptake and binding are severely inhibited by ATP. After the incubation of EDTA-treated etioplasts with pCS75, immunoprecipitation using antiserum to the small subunit of ribulose bisphosphate carboxylase/oxygenase from A. nidulans reveals the synthesis of small subunits. Treatment of etioplasts with 10 mM EDTA shows a 10-min duration to be optimal for the expression of chloramphenicol acetyltransferase encoded by pUC9-CM. A progressive increase in the expression of this enzyme is observed with an increase in the concentration of pUC9-CM in the DNA uptake medium. The plasmid-dependent incorporation of (/sup 35/S) methionine by EDTA-treated organelles declines markedly during cotyledon greening in vivo.

  15. Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize.

    Science.gov (United States)

    Wang, Xin-Xin; Hoffland, Ellis; Feng, Gu; Kuyper, Thomas W

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize ( Zea mays L.) cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi Funneliformis mosseae or Claroideoglomus etunicatum , were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg -1 soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1) phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2) increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3) lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.

  16. The calcium and vitamin D controversy

    DEFF Research Database (Denmark)

    Abrahamsen, Bo

    2017-01-01

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

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

    International Nuclear Information System (INIS)

    Gear, A.R.L.; Hallam, T.J.

    1986-01-01

    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 (IP 3 ), in particular, has been linked to mobilization of intracellular calcium in a number of cell types. The authors have examined the ability of IP 3 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 [ 45 Ca] 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

  19. Role of calcium in the dopaminergic effect on the proximal convoluted tubule of rat kidney

    International Nuclear Information System (INIS)

    Chan, Y.L.; Chatsudthipong, V.; Su-Tsai, S.M.; von Riotte, A.

    1986-01-01

    Microperfusion studies have shown that dopamine inhibits fluid and bicarbonate absorption in the rate proximal tubule. These studies are designed to examine the cellular mechanism underlying the proximal cellular response to dopamine action. In the isolated proximal cells, dopamine, in the concentration of 10 -6 M or less, had no effect on cAMP production. However, dopamine could increase cytosolic calcium concentration (from 90 nM to 210 nM) as measured by fluorospectrometry with fura-2 as a calcium indicator. Ca-45 flux studies have shown that dopamine could increase initial influx but not the steady state uptake of Ca. Dopamine could also increase efflux of Ca. In situ microperfusion of proximal tubule and peritubular capillaries has demonstrated that Ca ionophore, A23187 (10 -6 M), could simulate the inhibitory effects of dopamine on fluid and biocarbonate absorption. There was no additive effect observed when both agents were added together in the capillary perfusate. Removal of calcium from the perfusate could partially blunt the effect of dopamine. These results suggest that intracellular calcium plays a crucial role in the dopaminergic regulation of proximal tubular transport

  20. Thermodynamic study of the interaction between calcium and zoledronic acid by calorimetry

    International Nuclear Information System (INIS)

    Mostefa Side Larbi, Mohamed A.; Sauzet, Christophe; Piccerelle, Philippe; Cau, Pierre

    2016-01-01

    Bisphosphonates (BPs) are widely used to treat calcium disorders because of their structural and functional similarities with the organic pyrophosphates present in plasma and urine. BPs are well known for their strong interactions with calcium, and they have been shown to bind to hydroxyapatite or bone; however, no model exists for studying in greater detail how BPs and particularly amino-bisphosphonates (N-BPs) such as zolendronate (Zol) bind to free calcium. The aim of this work was to determine the effect of pH on Ca 2+ /Zol complex formation using isothermal titration calorimetry (ITC) because these effects might have important implications for the future development of a solid dosage form. In this study, using a predictive model, we can observe, the existence of three Ca 2+ /Zol complexes. Knowledge of the binding constant for each complex is helpful for predicting the predominance of the different species at different Ca 2+ /Zol ratios. Binding is due to ionic interaction between Ca 2+ and the negative charges formed by dissociated Zol as a function of the pKa. Ca 2+ fixation induces a strong rearrangement of the surrounding water molecules and causes proton release or uptake. The pH-dependent affinity of calcium for each site based on the model used in this work is proposed in detail, which might facilitate the development of new bisphosphonates and enable further elucidation of their mode of action.

  1. Sorption behavior of Zn(II) ions on synthetic apatitic calcium phosphates

    Science.gov (United States)

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

    2015-12-01

    The synthesis, characterization and the reactivity of apatitic calcium phosphates (Ca-HA, chemical formula Ca10(PO4)6(OH)2) is reported. Calcium carbonate (CaCO3) and potassium dihydrogen orthophosphate (KH2PO4) were selected as economical starting materials for the synthesis of Ca-HA under atmospheric conditions. Monocalcium phosphate monohydrate (MCPM), dicalcium phosphate dihydrate (DCPD), and octacalcium phosphate pentahydrate (OCP) were identified as the main intermediates of the synthesis reaction. The product obtained after 48 h of reaction contains mainly low-crystalline Ca-HA and small amounts of other calcium phosphates such as octacalcium phosphate (OCP), B-type carbonate apatite (CAP), as well as unreacted calcium carbonate. This Ca-HA was found to be active for the removal of Zn2+ from an aqueous solution. Its sorption capacity reached up to 120 mg of Zn2+ per g of Ca-HA powder after 24 h of reaction. The monitoring of soluble Zn, Ca and P during the sorption experiment allowed characterizing the mechanism of Zn uptake. Dissolution-precipitation, ionic exchange and surface complexation are the three main mechanisms involved in the sorption processes. The contribution of these mechanisms is discussed in detail.

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

    Science.gov (United States)

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

    2014-01-01

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

  3. Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Nalbant, Perihan [University of Duisburg-Essen, Faculty of Biology, Institute of Molecular Cell Biology (Germany); Buer, Jan; Knuschke, Torben; Westendorf, Astrid M. [University Hospital Essen, University of Duisburg-Essen, Institute of Medical Microbiology (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

    2012-06-15

    The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100-250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

  4. Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

    Science.gov (United States)

    Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan; Nalbant, Perihan; Buer, Jan; Knuschke, Torben; Westendorf, Astrid M.; Epple, Matthias

    2012-06-01

    The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100-250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

  5. Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

    International Nuclear Information System (INIS)

    Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan; Nalbant, Perihan; Buer, Jan; Knuschke, Torben; Westendorf, Astrid M.; Epple, Matthias

    2012-01-01

    The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100–250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

  6. Determination of maximum physiologic thyroid uptake and correlation with 24-hour RAI uptake value

    International Nuclear Information System (INIS)

    Duldulao, M.; Obaldo, J.

    2007-01-01

    Full text: In hyperthyroid patients, thyroid uptake values are overestimated, sometimes approaching or exceeding 100%. This is physiologically and mathematically impossible. This study was undertaken to determine the maximum physiologic thyroid uptake value through a proposed simple method using a gamma camera. Methodology: Twenty-two patients (17 females and 5 males), with ages ranging from 19-61 y/o (mean age ± SD; 41 ± 12), with 24-hour uptake value of >50%, clinically hyperthyroid and referred for subsequent radioactive iodine therapy were studied. The computed maximum physiologic thyroid uptake was compared with the 24-hour uptake using the paired Student t-test and evaluated using linear regression analysis. Results: The computed physiologic uptake correlated poorly with the 24-hour uptake value. However, in the male subgroup, there was no statistically significant difference between the two (p=0.77). Linear regression analysis gives the following relationship: physiologic uptake (%) = 77.76 - 0.284 (24-hour RAI uptake value). Conclusion: Provided that proper regions of interest are applied with correct attenuation and background subtraction, determination of physiologic thyroid uptake may be obtained using the proposed method. This simple method may be useful prior to I-131 therapy for hyperthyroidism especially when a single uptake determination is performed. (author)

  7. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  8. Non-calcium desulphurisation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Qian Zhu [IEA Clean Coal Centre, London (United Kingdom)

    2010-06-15

    Flue gas desulphurisation (FGD) is traditionally based on limestone/lime sorbent. The majority of the installed FGD systems worldwide use limestone or lime as sorbent. However, technologies are rapidly evolving that allow desulphurisation in regions where there are limited resources of lime or limestone. These technologies provide alternatives to limestone/lime scrubbers for efficient and cost effective control of SO{sub 2} emissions from coal combustion. This report reviews the existing and emerging non-calcium based FGD processes as well as FGD technologies currently under development that apply new concepts and different approaches. It looks at the fundamentals and features of these processes, the recent technical advances and their applications in coal-fired power plants. The capital and operating costs of the processes are evaluated where information available. 66 refs., 15 figs., 10 tabs.

  9. Oxalate: Effect on calcium absorbability

    International Nuclear Information System (INIS)

    Heaney, R.P.; Weaver, C.M.

    1989-01-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species

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

    Science.gov (United States)

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

    2012-05-15

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

  11. Calcium Blood Test: MedlinePlus Lab Test Information

    Science.gov (United States)

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

  12. Inflammation and insulin resistance induced by trans-10, cis-12 conjugated linoleic acid depend on intracellular calcium levels in primary cultures of human adipocytes

    DEFF Research Database (Denmark)

    Kennedy, Arion; Martinez, Kristina; Chung, Soonkyu

    2010-01-01

    We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) induced inflammation and insulin resistance in primary human adipocytes by activating nuclear factor kappaB (NFkappaB) and extracellular signal-related kinase (ERK) signaling. In this study, we demonstrated...... that the initial increase in intracellular calcium ([Ca2+]i) mediated by 10,12 CLA was attenuated by TMB-8, an inhibitor of calcium release from the endoplasmic reticulum (ER), by BAPTA, an intracellular calcium chelator, and by D609, a phospholipase C (PLC) inhibitor. Moreover, BAPTA, TMB-8, and D609 attenuated......, and suppression of peroxisome proliferator activated receptor gamma protein levels and insulin-stimulated glucose uptake. These data suggest that 10,12 CLA increases inflammation and insulin resistance in human adipocytes, in part by increasing [Ca2+]i levels, particularly calcium from the ER....

  13. Uptake of benzyladenine by excised watermelon cotyledons.

    Science.gov (United States)

    Lampugnani, M G; Fantelli, R; Longo, G P; Longo, C P; Rossi, G

    1981-07-01

    The uptake of 8-[(14)C]N(6)-benzyladenine (BA) was studied in excised watermelon (Citrullus vulgaris Schrad.) cotyledons 24 hours after the start of imbibition. The passive nature of this uptake is suggested by the following evidence: (a) no sign of saturation on increasing external concentration of BA; (b) no decrease in uptake under conditions that inhibit ATP synthesis; (c) no change in amount of radioactivity absorbed when cotyledons are frozen and thawed before the uptake test. About two-thirds of the radioactivity taken up is released after 12 hours of washing. If the washing is performed at 2 C very little radioactivity is released.There seems to be a correlation between the level of radioactivity (i.e. of BA + derivatives) present in the cotyledons and the magnitude of hormonal responses that are observed four days after uptake. This relationship holds regardless of whether a given level of radioactivity has been reached after a short period of uptake or after a long period of uptake followed by washing.

  14. Radioisotopic Studies of Brain Uptake

    International Nuclear Information System (INIS)

    Oldendorf, W. H.

    1970-01-01

    Measurements of the uptake of radioactive substances in the brain tissues after their administration by injection or inhalation provide an a traumatic approach to the study of blood flow and metabolic processes in the brain. This paper reviews the anatomical,physiological and physical problems arising in the measurement of radioactivity in the brain. The factors governing the passage of various classes of substances through the brain capillaries and their transport through the brain tissues are first considered. The physical problems arising in the measurement of radioactivity in the brain are then discussed. The main difficulties in such measurements is shown to arise from the contribution to the observed counting rate from radioactivity in the scalp and skull. This contribution can be minimized by the use of special collimators designed to view only a part of the brain but to include in their field of view a minimum of non-neural tissue. A further possibility arises with radioisotopes such as 113 In m which emit characteristic X radiation as well as y radiation since the contribution of the former to the total observed counting rate is almost entirely due to radioactivity in the superficial tissues whereas that of the latter is due to radioactivity in the superficial tissues and the brain. By recording the counting rates in appropriate channels of the photon spectrum it is thus possible to correct the results for radioactivity in the scalp and skull. With radioisotopes such as 75 Sc which emit two or more photons in cascade, coincidence counting techniques offer still a further possibility to minimize the contribution from radioactivity in the superficial tissues. Various potential applications of these techniques are described. (author)

  15. P-32 uptake in lentic algae

    International Nuclear Information System (INIS)

    Strange, J.R.; Williamson, G.D.; Fletcher, D.J.

    1975-01-01

    A study of the Flat Creek Embayment of Lake Sidney Lanier near Gainesville, Georgia revealed three genera of algae, Chlorococcum, Fragillaria and Nostoc, to be prominent in this eutrophic region of the lake. The algae was grown in phosphate-rich media and subsequently labelled with P-32. All species incorporated luxury amounts of phosphorus as determined by the uptake of P-32. The results indicate that the P-32 uptake is proportional to the surface-per-volume ratio. The higher surface-per-volume ratio resulted in greater uptake of P-32

  16. Hydrogen uptake by Azolla-Anabaena

    International Nuclear Information System (INIS)

    Ruschel, A.P.; Freitas, J.R. de; Silva, P.M.

    1984-01-01

    The hydrogen uptake in the Azolla-Anabaena system is studied. Tritium is used as tracer. Plants are incubated under different atmosphere composition: a) Air + 3 H 2 ; b) Air + CO 2 + 3 H 2 + CO; c) Air + 3 H 2 + CO; d) Air + CO 2 + 3 H 2 + CO to study the pathway of absorbed hydrogen in the Azolla - Anabaena system. Azolla-Anabaena showed greater hydrogen uptake under argonium atmosphere than under air. Carbon monoxide decreased hydrogen uptake. There are evidences of recycling of the hydrogen evolved through notrogenease. (Author) [pt

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

    International Nuclear Information System (INIS)

    Teir, Sebastian; Eloneva, Sanni; Zevenhoven, Ron

    2005-01-01

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

  18. Chapter 15. Measurement of the main calcium metabolism processes

    International Nuclear Information System (INIS)

    Milhaud, G.

    1975-01-01

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

  19. Uptake of cadmium from hydroponic solutions by willows ( Salix spp ...

    African Journals Online (AJOL)

    Salix integra 'Weishanhu') and Yizhibi (S. integra 'Yizhibi') were chosen as model plants to evaluate their potential for uptake of cadmium from hydroponic culture and relative uptake mechanism. Cadmium uptake showed a linear increase in the ...

  20. Calcium phosphates: what is the evidence?

    Science.gov (United States)

    Larsson, Sune

    2010-03-01

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