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Sample records for extracellular calcium concentrations

  1. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

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

    2001-01-01

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

  2. Nitric oxide inhibited the melanophore aggregation induced by extracellular calcium concentration in snakehead fish, Channa punctatus.

    Science.gov (United States)

    Biswas, Saikat P; Palande, Nikhil V; Jadhao, Arun G

    2011-12-01

    We studied the role of nitric oxide (NO) and extra-cellular Ca(2+) on the melanophores in Indian snakehead teleost, Channa punctatus. Increase of Ca(2+) level in the external medium causes pigment aggregation in melanophores. This pigment-aggregating effect was found to be inhibited when the external medium contained spontaneous NO donor, sodium nitro prusside (SNP) at all the levels of concentration tested. Furthermore, it has been observed that SNP keeps the pigment in dispersed state even after increasing the amount of Ca(2+). In order to test whether NO donor SNP causes dispersion of pigments or not is checked by adding the inhibitor of nitric oxide synthase, N-omega-Nitro-L-arginine (L-NNA) in the medium. It has been noted that the inhibitor L-NNA blocked the effect of NO donor SNP causing aggregation of pigments. In that way NO is inhibiting the effect of extracellular Ca(2+), keeping the pigment dispersed.

  3. Effects of extracellular iron concentration on calcium absorption and relationship between Ca2+ and cell apoptosis in Caco-2 cells

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Qing Li; Xiang-Lin Duan; Yan-Zhong Chang

    2005-01-01

    AIM: To determine the method of growing small intestinal epithelial cells in short-term primary culture and to investigate the effect of extracellular iron concentration ([Fe3+]) on calcium absorption and the relationship between the rising intracellular calcium concentration ([Ca2+]i) and cell apoptosis in human intestinal epithelial Caco-2 cells. METHODS: Primary culture was used for growing small intestinal epithelial cells. [Ca2+]i was detected by a confocal laser scanning microscope. The changes in [Ca2+]i were represented by fluorescence intensity (FI). The apoptosis was evaluated by flow cytometry.RESULTS: Isolation of epithelial cells and preservation of its three-dimensional integrity were achieved using the digestion technique of a mixture of collagenase Ⅺ and dispase Ⅰ. Purification of the epithelial cells was facilitated by using a simple differential sedimentation method. The results showed that proliferation of normal gut epithelium in vitro was initially dependent upon the maintenance of structural integrity of the tissue. If 0.25% trypsin was used for digestion, the cells were severely damaged and very difficult to stick to the Petri dish for growing. The Fe3+ chelating agent desferrioxamine (100, 200 and 300 μmol/L) increased the FI of Caco-2 cells from 27.50±13.18 (control,n = 150) to 35.71±13.99 (n = 150, P<0.01), 72.19±35.40 (n = 150, P<0.01) and 211.34±29.03 (n = 150, P<0.01) in a concentration-dependent manner. There was a significant decrease in the FI of Caco-2 cells treated by ferric ammonium citrate (FAC, a Fe3+ donor; 10, 50 and 100 μmol/L). The FIvalue of Caco-2 cells treated by FAC was 185.85±33.77 (n = 150, P<0.01), 122.73±58.47 (n = 150, P<0.01), and 53.29±19.82 (n = 150, P<0.01), respectively, suggesting that calcium absorption was influenced by [Fe3+]. Calcium ionophore A23187 (0.1, 1.0 and 10 μmol/L) increased the FI of Caco-2 cells from 40.45±13.95 (control, n = 150) to 45.19±21.95 (n = 150, P<0

  4. Extracellular Calcium and Magnesium

    African Journals Online (AJOL)

    i cellular and neuronal metabolism and functions. The objective of ... as having preeclampsia or eclampsia, in the same age range. ... Booking status Number (n) ("/o) Number (n) (%). Booked 7 ... is influx of calcium ions into the cell leacling to.

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

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    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.

  6. Effect of extracellular calcium on the additive effect of theophylline on the cardiac response to catecholamine

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    Shamkuwar Prashant

    2008-01-01

    Full Text Available At different extracellular calcium concentrations, the positive inotropic effect of isoproterenol and isoproterenol in combination with theophylline, a phosphodiesterase inhibitor have been evaluated in the isolated frog heart and the isolated guinea pig left atria to investigate whether extracellular calcium produces any effect on the additive effect of the theophylline on the cardiac response to catecholamine. Cumulative dose response study of isoproterenol and isoproterenol in presence of theophylline at different extracellular calcium concentration was performed. The study revealed an increase in additive effect of theophylline on the cardiac response to catecholamine with increase in extracellular calcium concentration, but increase in extracellular calcium concentration decreased the myocardial responsiveness to additive effect of theophylline and isoproterenol combination. The mechanism of positive inotropic effect of isoproterenol and in combination with theophylline involves increase in intracellular cAMP by different pathways and extracellular calcium produces positive inotropic effect by initiating the interaction between the contractile proteins actin and myosin. The study revealed that an increase in the concentration of extracellular calcium increased the additive effect of theophylline and isoproterenol combination, but a decrease in the myocardial responsiveness was observed.

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

    DEFF Research Database (Denmark)

    Knudsen, Torben; Johansen, Torben

    1989-01-01

    of an enzyme, and it is mediated by the Na+ -K+ pump located in the plasma membrane. It is demonstrated that the activity of the Na+ -K+ pump mechanism is inhibited by low concentrations of extracellular calcium (0.1-1.2 mmol l-1). The possibility is discussed that calcium-deprivation may increase the pump...

  8. Extracellular calcium sensing receptor in human pancreatic cells

    Science.gov (United States)

    Rácz, G Z; Kittel, Á; Riccardi, D; Case, R M; Elliott, A C; Varga, G

    2002-01-01

    Background and aims: The extracellular calcium sensing receptor (CaR) plays a key role in the calcium homeostatic system and is therefore widely expressed in tissues involved in calcium metabolism. However, the CaR has also been identified in other tissues where its role is less clear. We have investigated the presence of the CaR in the human pancreas. Methods: Messenger RNA for the CaR was detected by reverse transcription-polymerase chain reaction and the protein was localised by immunostaining. CaR function was assayed in Capan-1 cells by measuring intracellular calcium and [3H] thymidine incorporation. Results: The receptor was highly expressed in human pancreatic ducts. It was also expressed in exocrine acinar cells, in islets of Langerhans, and in intrapancreatic nerves and blood vessels. The CaR was expressed in both normal and neoplastic human tissue samples but was detected in only one of five ductal adenocarcinoma cells lines examined. Experiments on the CaR expressing adenocarcinoma cell line Capan-1 showed that the CaR was functional and was linked to mobilisation of intracellular calcium. Stimulation of the CaR reduced Capan-1 cell proliferation. Conclusions: We propose that the CaR may play multiple functional roles in the human pancreas. In particular, the CaR on the duct luminal membrane may monitor and regulate the Ca2+ concentration in pancreatic juice by triggering ductal electrolyte and fluid secretion. This could help to prevent precipitation of calcium salts in the duct lumen. The CaR may also help to regulate the proliferation of pancreatic ductal cells. PMID:12377811

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

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    Brian L Jones

    2016-03-01

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

  10. Extracellular Ca2+ is a danger signal activating the NLRP3 inflammasome through G protein-coupled calcium sensing receptors

    DEFF Research Database (Denmark)

    Rossol, Manuela; Pierer, Matthias; Raulien, Nora;

    2012-01-01

    Activation of the NLRP3 inflammasome enables monocytes and macrophages to release high levels of interleukin-1ß during inflammatory responses. Concentrations of extracellular calcium can increase at sites of infection, inflammation or cell activation. Here we show that increased extracellular cal......, and this effect was inhibited in GPRC6A(-/-) mice. Our results demonstrate that G-protein-coupled receptors can activate the inflammasome, and indicate that increased extracellular calcium has a role as a danger signal and amplifier of inflammation....

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

    Science.gov (United States)

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

    2012-11-01

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

  12. Differential effect of extracellular calcium on the Na(+)-K+ pump activity in intact polymorphonuclear leucocytes and erythrocytes

    DEFF Research Database (Denmark)

    Petersen, R H; Knudsen, T; Johansen, Torben

    1991-01-01

    The effect of extracellular calcium on the Na(+)-K+ pump activity in human polymorphonuclear leucocytes and erythrocytes was studied and compared with the activity in mixed peritoneal leucocytes from rats. While there was maximal decrease in the pump activity (25-30%) of leucocytes from both rat...... and human by calcium 0.6 mM, a concentration of 0.1 mM caused a substantial decrease indicating a high sensitivity for extracellular calcium. In contrast, calcium had no effect on the pump activity in erythrocytes. The effect of calcium on the pump activity in leucocytes may be due to regulation...

  13. Effects of extracellular calcium and sodium on depolarization-induced automaticity in guinea pig papillary muscle.

    Science.gov (United States)

    Katzung, B G

    1975-07-01

    Regenerative discharge of action potentials is induced in mammalian papillary muscles by passage of small depolarizing currents. In this paper, the effects of various extracellular calcium and sodium concentrations and of tetrodotoxin on this phenomenon were studied in guinea pig papillary muscles in a sucrose gap chamber. Phase 4 diastolic depolarization was found to be associated with an increase in membrane resistance. The slope of phase 4 depolarization was decreased by reductions in extracellular calcium or sodium concentration. The range of maximum diastolic potentials and the thresholds from which regenerative potentials arose were reduced, especially at the positive limit of potentials, by a reduction in either ion. It was concluded that both calcium and sodium influence diastolic depolarization and participate in the regenerative action potentials of depolarization-induced ventricular automaticity.

  14. The functional expression of extracellular calcium-sensing receptor in rat pulmonary artery smooth muscle cells

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    Zhang Wei-hua

    2011-02-01

    Full Text Available Abstract Background The extracellular calcium-sensing receptor (CaSR belongs to family C of the G protein coupled receptors. Whether the CaSR is expressed in the pulmonary artery (PA is unknown. Methods The expression and distribution of CaSR were detected by RT-PCR, Western blotting and immunofluorescence. PA tension was detected by the pulmonary arterial ring technique, and the intracellular calcium concentration ([Ca2+]i was detected by a laser-scanning confocal microscope. Results The expressions of CaSR mRNA and protein were found in both rat pulmonary artery smooth muscle cells (PASMCs and PAs. Increased levels of [Ca2+]o (extracellular calcium concentration or Gd3+ (an agonist of CaSR induced an increase of [Ca2+]i and PAs constriction in a concentration-dependent manner. In addition, the above-mentioned effects of Ca2+ and Gd3+ were inhibited by U73122 (specific inhibitor of PLC, 2-APB (specific antagonist of IP3 receptor, and thapsigargin (blocker of sarcoplasmic reticulum calcium ATPase. Conclusions CaSR is expressed in rat PASMCs, and is involved in regulation of PA tension by increasing [Ca2+]i through G-PLC-IP3 pathway.

  15. Molecular Basis of the Extracellular Ligands Mediated Signaling by the Calcium Sensing Receptor

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    Chen Zhang

    2016-09-01

    Full Text Available Ca2+-sensing receptors (CaSRs play a central role in regulating extracellular calcium concentration ([Ca2+]o homeostasis and many (pathophysiological processes in multiple organs. This regulation is orchestrated by a cooperative response to extracellular stimuli such as small changes in Ca2+, Mg2+, amino acids and other ligands. In addition, CaSR is a pleiotropic receptor regulating several intracellular signaling pathways, including calcium mobilization and intracellular calcium oscillation. Nearly 200 mutations and polymorphisms have been found in CaSR in relation to a variety of human disorders associated with abnormal Ca2+ homeostasis. In this review, we summarize efforts directed at identifying binding sites for calcium and amino acids. Both homotropic cooperativity among multiple calcium binding sites and heterotropic cooperativity between calcium and amino acid were revealed using computational modeling, predictions, and site-directed mutagenesis coupled with functional assays. The hinge region of the bilobed Venus flytrap (VFT domain of CaSR plays a pivotal role in coordinating multiple extracellular stimuli, leading to cooperative responses from the receptor. We further highlight the extensive number of disease-associated mutations that have also been shown to affect CaSR’s cooperative action via several types of mechanisms. These results provide insights into the molecular bases of the structure and functional cooperativity of this receptor and other members of family C of the G protein-coupled receptors (cGPCRs in health and disease states, and may assist in the prospective development of novel receptor-based therapeutics.

  16. Effects of Extracellular Calcium and 1,25 dihydroxyvitamin D3 on Sebaceous Gland Cells In vitro and In vivo.

    Science.gov (United States)

    Zouboulis, Christos C; Seltmann, Holger; Abdel-Naser, M Badawy; Hossini, Amir M; Menon, Gopinathan K; Kubba, Raj

    2017-03-10

    Calcium and 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) are promoters of epithelial cell functions; however their effects on sebaceous glands are unknown. In this study, morphology, ultrastructure, cell numbers, lipid synthesis and apoptosis of SZ95 sebocytes were assessed in vitro under different concentrations of extracellular calcium with or without 1,25(OH)2D3. Moreover, serum calcium and 1,25(OH)2D3 levels were assessed in acne and non-acne patients (controls). Under conditions of low extracellular calcium, lipogenesis and cell detachment were observed. Increasing extracellular calcium enhanced sebocyte numbers, induced epithelial morphology and reduced lipogenesis. Moreover, a reduction in extracellular calcium reduced E-cadherin and enhanced caspase 3/7 activity (apoptosis), whereas calcium chelation by EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid) resulted in enhanced lipogenesis. 1,25(OH)2D3 decreased sebaceous lipogenesis, but also induced signs of autophagy. In the clinical study, patients and controls exhibited normal serum calcium levels. Younger acne patients presented lower 1,25(OH)2D3 levels than did older ones. In conclusion, extracellular calcium and 1,25(OH)2D3 regulate sebocyte morphology, increase cell numbers, decrease sebaceous lipogenesis and induce cell autophagy in vitro. The increased ionized calcium and the reduced 1,25(OH)2D3 levels detected in the serum of younger patients with acne may contribute respectively to increased sebaceous gland volume and enhanced lipogenesis.

  17. Calcium Nutrition and Extracellular Calcium Sensing: Relevance for the Pathogenesis of Osteoporosis, Cancer and Cardiovascular Diseases

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    Meinrad Peterlik

    2013-01-01

    Full Text Available Through a systematic search in Pubmed for literature, on links between calcium malnutrition and risk of chronic diseases, we found the highest degree of evidence for osteoporosis, colorectal and breast cancer, as well as for hypertension, as the only major cardiovascular risk factor. Low calcium intake apparently has some impact also on cardiovascular events and disease outcome. Calcium malnutrition can causally be related to low activity of the extracellular calcium-sensing receptor (CaSR. This member of the family of 7-TM G-protein coupled receptors allows extracellular Ca2+ to function as a “first messenger” for various intracellular signaling cascades. Evidence demonstrates that Ca2+/CaSR signaling in functional linkage with vitamin D receptor (VDR-activated pathways (i promotes osteoblast differentiation and formation of mineralized bone; (ii targets downstream effectors of the canonical and non-canonical Wnt pathway to inhibit proliferation and induce differentiation of colorectal cancer cells; (iii evokes Ca2+ influx into breast cancer cells, thereby activating pro-apoptotic intracellular signaling. Furthermore, Ca2+/CaSR signaling opens Ca2+-sensitive K+ conductance channels in vascular endothelial cells, and also participates in IP3-dependent regulation of cytoplasmic Ca2+, the key intermediate of cardiomyocyte functions. Consequently, impairment of Ca2+/CaSR signaling may contribute to inadequate bone formation, tumor progression, hypertension, vascular calcification and, probably, cardiovascular disease.

  18. Electrical slow waves in the mouse oviduct are dependent on extracellular and intracellular calcium sources

    Science.gov (United States)

    Dixon, Rose Ellen; Britton, Fiona C.; Baker, Salah A.; Hennig, Grant W.; Rollings, Christina M.; Sanders, Kenton M.

    2011-01-01

    Spontaneous contractions of the myosalpinx are critical for oocyte transport along the oviduct. Slow waves, the electrical events that underlie myosalpinx contractions, are generated by a specialized network of pacemaker cells called oviduct interstitial cells of Cajal (ICC-OVI). The ionic basis of oviduct pacemaker activity is unknown. Intracellular recordings and Ca2+ imaging were performed to examine the role of extracellular and intracellular Ca2+ sources in slow wave generation. RT-PCR was performed to determine the transcriptional expression of Ca2+ channels. Molecular studies revealed most isoforms of L- and T-type calcium channels (Cav1.2,1.3,1.4,3.1,3.2,3.3) were expressed in myosalpinx. Reduction of extracellular Ca2+ concentration ([Ca2+]o) resulted in the abolition of slow waves and myosalpinx contractions without significantly affecting resting membrane potential (RMP). Spontaneous Ca2+ waves spread through ICC-OVI cells at a similar frequency to slow waves and were inhibited by reduced [Ca2+]o. Nifedipine depolarized RMP and inhibited slow waves; however, pacemaker activity returned when the membrane was repolarized with reduced extracellular K+ concentration ([K+]o). Ni2+ also depolarized RMP but failed to block slow waves. The importance of ryanodine and inositol 1,4,5 trisphosphate-sensitive stores were examined using ryanodine, tetracaine, caffeine, and 2-aminoethyl diphenylborinate. Results suggest that although both stores are involved in regulation of slow wave frequency, neither are exclusively essential. The sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitor cyclopiazonic acid inhibited pacemaker activity and Ca2+ waves suggesting that a functional SERCA pump is necessary for pacemaker activity. In conclusion, results from this study suggest that slow wave generation in the oviduct is voltage dependent, occurs in a membrane potential window, and is dependent on extracellular calcium and functional SERCA pumps. PMID:21881003

  19. Calcium concentration in the CAPD dialysate

    DEFF Research Database (Denmark)

    Bro, S; Brandi, L; Daugaard, H

    1998-01-01

    OBJECTIVE: To evaluate risk/benefit of various continuous ambulatory peritoneal dialysis (CAPD) dialysate calcium concentrations. DATA SOURCES: A review of the literature on the effects of various CAPD dialysate Ca concentrations on plasma Ca, plasma phosphate, plasma parathyroid hormone (PTH...... with a reduced dialysate Ca concentration (1.00, 1.25, or 1.35 mmol/L) improved the tolerance to calcium carbonate and/or vitamin D metabolites and reduced the need for Al-containing phosphate binders. When using dialysate Ca 1.25 or 1.35 mmol/L, the initial decrease of plasma Ca and increase of PTH could easily...... be reversed with an immediate adjustment of the treatment. After 3 months, stable plasma Ca and PTH levels could be maintained using only monthly investigations. In patients with hypercalcemia and elevated PTH levels, treatment with dialysate Ca concentrations below 1.25 mmol/L implied a considerable risk...

  20. Regulation of the arachidonic acid-stimulated respiratory burst in neutrophils by intra- cellular and extracellular calcium

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The respiratory burst is an important physiological function ofthe neutrophils in killing the bacteria invading in human body. We used chemiluminescence method to measure the exogenous arachidonic acid-stimulated respiratory burst, and measured the cytosolic free calcium concentration in neutrophils by the fluorescence method. It was found that, on one hand, the arachidonic acid-stimulated respiratory burst was enhanced by elevating the cytosolic free calcium concentration in neutrophils with a potent endomembrane Ca2+-ATPase inhibitor, Thapsgargin; on the other hand, chelating the intracellular or extracellular calcium by EGTA or BAPTA inhibited the respiratory burst. Results showed that calcium plays an important regulatory role in the signaling pathway involved in the exogenous arachidonic acid-stimulated respiratory burst of neutrophils.

  1. The Relationship of Blood Pressure with Intra- Or extracellular and Bone Calcium Merabolisms in the Elderly

    OpenAIRE

    Sugihara, Nobuyuki; Matsuzaki, Masunori

    1994-01-01

    We investigated the correlations of blood pressure with intra- or extracellular and bone calcium matabolisms in the elderly. We measured serum calcium (Ca), inorganic phosphorus (Pi), C-terminal parathyroid hormone fragment (PTH-C), and calcitonin. Intracellular free calcium ([Ca2+]I) in platelet and erythrocyte was measured by fura- 2/AM from dual excitation wavelength using a fluorescence spectrophotometer. We calculated bone mineral content (BMC) of lumbar vertebral body using a calibratio...

  2. Vertebrate extracellular calcium-sensing receptor evolution: selection in relation to life history and habitat.

    Science.gov (United States)

    Herberger, Amanda L; Loretz, Christopher A

    2013-03-01

    Ionic calcium (Ca(2+)) supports essential functions within physiological systems, and consequently its concentration is homeostatically regulated within narrow bounds in the body fluids of animals through endocrine effects at ion-transporting osmoregulatory tissues. In vertebrates, extracellular Ca(2+) is detected at the cell surface by the extracellular calcium-sensing receptor (CaSR), a member of the G protein-coupled receptor (GPCR) superfamily. Interestingly, the taxonomic distribution of CaSRs is restricted to vertebrates, with some CaSR-like receptors apparently present in non-vertebrate chordates. Since bone is a known Ca(2+) storage site and is characteristically restricted to the vertebrate lineage, we hypothesized a functional association of CaSR with vertebrate skeleton that may have an ancient origin. Protein sequence alignment and phylogenetic analysis of vertebrate CaSRs and related GPCRs of the glutamate receptor-like family expose similarities and indel differences among these receptors, and reveal the evolutionary history of CaSRs. Evolutionary selection was tested statistically by evaluating the relationship between non-synonymous (replacement, dN) versus synonymous (silent, dS) amino acid substitution rates (as dN/dS) of protein-coding DNA sequences among branches of the estimated protein phylogeny. On a background of strong purifying selection (dN/dS1) was detected on some branches to major clades in the CaSR phylogeny, especially to the tetrapod vertebrate CaSRs and chordate CaSR-like branches. Testing also revealed overall purifying selection at the codon level. At some sites relaxation from strong purifying selection was seen, but evidence for adaptive evolution was not detected for individual sites. The results suggest purifying selection of CaSRs, and of adaptive evolution among some major vertebrate clades, reflecting clade specific differences in natural history and organismal biology, including skeletal involvement in calcium homeostasis

  3. Upregulation of parathyroid VDR expression by extracellular calcium is mediated by ERK1/2-MAPK signaling pathway.

    Science.gov (United States)

    Cañadillas, Sagrario; Canalejo, Rocio; Rodriguez-Ortiz, Maria Encarnacion; Martinez-Moreno, Julio Manuel; Estepa, Jose Carlos; Zafra, Rafael; Perez, Jose; Muñoz-Castañeda, Juan Rafael; Canalejo, Antonio; Rodriguez, Mariano; Almaden, Yolanda

    2010-05-01

    We have previously demonstrated that the activation of rat parathyroid calcium-sensing receptor (CaSR) upregulates VDR expression in vivo (Garfia B, Cañadillas S, Luque F, Siendones E, Quesada M, Almadén Y, Aguilera-Tejero E, Rodríguez M. J Am Soc Nephrol 13: 2945-2952, 2002; Rodriguez ME, Almaden Y, Cañadillas S, Canalejo A, Siendones E, Lopez I, Aguilera-Tejero E, Martin D, Rodriguez M. Am J Physiol Renal Physiol 292: F1390-F1395, 2007). The present study was designed to characterize the signaling system that mediates the stimulation of parathyroid VDR gene expression by extracellular calcium. Experiments were performed in vitro by the incubation of rat parathyroid glands and in vivo with normal and uremic (Nx) rats receiving injections of CaCl(2) or EDTA to obtain hypercalcemic or hypocalcemic clamps. A high calcium concentration increased VDR expression. The addition of arachidonic acid (AA) to the low-calcium medium produced an increase in VDR mRNA of the same magnitude as that observed with high calcium. The addition of ionophore to the low-calcium medium also increased VDR mRNA expression. High calcium or the addition of AA to the low-calcium medium induced the activation (phosphorylation) of ERK1/2-MAPK. The specific inhibition of the ERK1/2-MAPK activity prevented the stimulation of VDR expression by high calcium or AA. These results suggest that AA regulates parathyroid VDR gene expression through the activation of the ERK1/2-MAPK. CaSR activation induced the activation of transcription factor Sp1, but not of NF-κB p50 or p65 or activator protein-1. The addition of AA to the low-calcium medium increased specific DNA-binding activity of Sp1 to almost the same level as high calcium, which was prevented by the inhibition of ERK1/2. Furthermore, mithramycin A (a Sp1 inhibitor) prevented the upregulation of VDR mRNA by high calcium. Finally, both sham and Nx hypercalcemic rats showed similar increased levels of VDR mRNA compared with sham and Nx

  4. Physiological responses of osteoblasts to cyclic stretching and the change of intracellular calcium concentration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The development of bone tissues is regulated by mechanical stimulation. Cyclic stretching was applied to the osteoblasts that were delivered from rat calvarie. The results showed that stretching at 500 με increased the cell proliferation while loading at 1000 με and 1500 με inhabited cell growth. Loading alsoincreased the adhesive force between cells and substrate as well as spreading areas of osteobalsts. Furthermore, the fluorescence probe Fluo-3/AM was used to investigate the effect of stretching stimulation on the intracellular calcium concentration of osteoblasts. The intracellular calcium concentration of osteoblasts that were stretched at 500 με for 5 min was 92.9% higher than the control. After being treated with the panax ontoginseng saponins, the stretched osteoblasts still expressed 28.6% higher intracellular calcium concentration than that of the control, which proved that both the influx of extracellular calcium and the release of intracellular calcium store were involved in the increase of intracellular calcium concentration when osteoblasts responded to the cyclic stretching. And the influx of extracellular calcium through transmembrance channel played a main role.

  5. Arterial Stiffness and Dialysis Calcium Concentration

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    Fabrice Mac-Way

    2011-01-01

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

  6. Calcium carbonate formation on mica supported extracellular polymeric substance produced by Rhodococcus opacus

    Science.gov (United States)

    Szcześ, Aleksandra; Czemierska, Magdalena; Jarosz-Wilkołazka, Anna

    2016-10-01

    Extracellular polymeric substance (EPS) extracted from Rhodococcus opacus bacterial strain was used as a matrix for calcium carbonate precipitation using the vapour diffusion method. The total exopolymer and water-soluble exopolymer fraction of different concentrations were spread on the mica surface by the spin-coating method. The obtained layers were characterized using the atomic force microscopy measurement and XPS analysis. The effects of polymer concentration, initial pH of calcium chloride solution and precipitation time on the obtained crystals properties were investigated. Raman spectroscopy and scanning electron microscopy were used to characterize the precipitated minerals. It was found that the type of precipitated CaCO3 polymorph and the crystal size depend on the kind of EPS fraction. The obtained results indicates that the water soluble fraction favours vaterite dissolution and calcite growth, whereas the total EPS stabilizes vaterite and this effect is stronger at basic pH. It seems to be due to different contents of the functional group of EPS fractions.

  7. Outward potassium current oscillations in macrophage polykaryons: extracellular calcium entry and calcium-induced calcium release

    Directory of Open Access Journals (Sweden)

    Saraiva R.M.

    1997-01-01

    Full Text Available Outward current oscillations associated with transient membrane hyperpolarizations were induced in murine macrophage polykaryons by membrane depolarization in the absence of external Na+. Oscillations corresponded to a cyclic activation of Ca2+-dependent K+ currents (IKCa probably correlated with variations in intracellular Ca2+ concentration. Addition of external Na+ (8 mM immediately abolished the outward current oscillations, suggesting that the absence of the cation is necessary not only for their induction but also for their maintenance. Oscillations were completely blocked by nisoldipine. Ruthenium red and ryanodine reduced the number of outward current cycles in each episode, whereas quercetin prolonged the hyperpolarization 2- to 15-fold. Neither low molecular weight heparin nor the absence of a Na+ gradient across the membrane had any influence on oscillations. The evidence suggests that Ca2+ entry through a pathway sensitive to Ca2+ channel blockers is elicited by membrane depolarization in Na+-free medium and is essential to initiate oscillations, which are also dependent on the cyclic release of Ca2+ from intracellular Ca2+-sensitive stores; Ca2+ ATPase acts by reducing intracellular Ca2+, thus allowing slow deactivation of IKCa. Evidence is presented that neither a Na+/Ca2+ antiporter nor Ca2+ release from IP3-sensitive Ca2+ stores participate directly in the mechanism of oscillation

  8. Extracellular calcium triggers unique transcriptional programs and modulates staurosporine-induced cell death in Neurospora crassa

    Directory of Open Access Journals (Sweden)

    A. Pedro Gonçalves

    2014-08-01

    Full Text Available Alterations in the intracellular levels of calcium are a common response to cell death stimuli in animals and fungi and, particularly, in the Neurospora crassa response to staurosporine. We highlight the importance of the extracellular availability of Ca2+ for this response. Limitation of the ion in the culture medium further sensitizes cells to the drug and results in increased accumulation of reactive oxygen species (ROS. Conversely, an approximately 30-fold excess of external Ca2+ leads to increased drug tolerance and lower ROS generation. In line with this, distinct staurosporine-induced cytosolic Ca2+ signaling profiles were observed in the absence or presence of excessive external Ca2+. High-throughput RNA sequencing revealed that different concentrations of extracellular Ca2+ define distinct transcriptional programs. Our transcriptional profiling also pointed to two putative novel Ca2+-binding proteins, encoded by the NCU08524 and NCU06607 genes, and provides a reference dataset for future investigations on the role of Ca2+ in fungal biology.

  9. Recent advances in understanding the extracellular calcium-sensing receptor [version 1; referees: 3 approved

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    Matilde Colella

    2016-10-01

    Full Text Available The extracellular calcium-sensing receptor (CaR, a ubiquitous class C G-protein-coupled receptor (GPCR, is responsible for the control of calcium homeostasis in body fluids. It integrates information about external Ca2+ and a surfeit of other endogenous ligands into multiple intracellular signals, but how is this achieved? This review will focus on some of the exciting concepts in CaR signaling and pharmacology that have emerged in the last few years.

  10. Elevation of extracellular Ca2+ induces store-operated calcium entry via calcium-sensing receptors: a pathway contributes to the proliferation of osteoblasts.

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    Fen Hu

    Full Text Available AIMS: The local concentration of extracellular Ca(2+ ([Ca(2+]o in bone microenvironment is accumulated during bone remodeling. In the present study we investigated whether elevating [Ca(2+]o induced store-operated calcium entry (SOCE in primary rat calvarial osteoblasts and further examined the contribution of elevating [Ca(2+]o to osteoblastic proliferation. METHODS: Cytosolic Ca(2+ concentration ([Ca(2+]c of primary cultured rat osteoblasts was detected by fluorescence imaging using calcium-sensitive probe fura-2/AM. Osteoblastic proliferation was estimated by cell counting, MTS assay and ATP assay. Agonists and antagonists of calcium-sensing receptors (CaSR as well as inhibitors of phospholipase C (PLC, SOCE and voltage-gated calcium (Cav channels were applied to study the mechanism in detail. RESULTS: Our data showed that elevating [Ca(2+]o evoked a sustained increase of [Ca(2+]c in a dose-dependent manner. This [Ca(2+]c increase was blocked by TMB-8 (Ca(2+ release inhibitor, 2-APB and BTP-2 (both SOCE blockers, respectively, whereas not affected by Cav channels blockers nifedipine and verapamil. Furthermore, NPS2143 (a CaSR antagonist or U73122 (a PLC inhibitor strongly reduced the [Ca(2+]o-induced [Ca(2+]c increase. The similar responses were observed when cells were stimulated with CaSR agonist spermine. These data indicated that elevating [Ca(2+]o resulted in SOCE depending on the activation of CaSR and PLC in osteoblasts. In addition, high [Ca(2+]o significantly promoted osteoblastic proliferation, which was notably reversed by BAPTA-AM (an intracellular calcium chelator, 2-APB, BTP-2, TMB-8, NPS2143 and U73122, respectively, but not affected by Cav channels antagonists. CONCLUSIONS: Elevating [Ca(2+]o induced SOCE by triggering the activation of CaSR and PLC. This process was involved in osteoblastic proliferation induced by high level of extracellular Ca(2+ concentration.

  11. Stimulation of Suicidal Erythrocyte Death by Increased Extracellular Phosphate Concentrations

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    Jakob Voelkl

    2014-02-01

    Full Text Available Background/Aim: Anemia in renal insufficiency results in part from impaired erythrocyte formation due to erythropoietin and iron deficiency. Beyond that, renal insufficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine-exposure at the erythrocyte surface. Eryptosis may be stimulated by increase of cytosolic Ca2+-activity ([Ca2+]i. Several uremic toxins have previously been shown to stimulate eryptosis. Renal insufficiency is further paralleled by increase of plasma phosphate concentration. The present study thus explored the effect of phosphate on erythrocyte death. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, and [Ca2+]i from Fluo3-fluorescence. Results: Following a 48 hours incubation, the percentage of phosphatidylserine exposing erythrocytes markedly increased as a function of extracellular phosphate concentration (from 0-5 mM. The exposure to 2 mM or 5 mM phosphate was followed by slight but significant hemolysis. [Ca2+]i did not change significantly up to 2 mM phosphate but significantly decreased at 5 mM phosphate. The effect of 2 mM phosphate on phosphatidylserine exposure was significantly augmented by increase of extracellular Ca2+ to 1.7 mM, and significantly blunted by nominal absence of extracellular Ca2+, by additional presence of pyrophosphate as well as by presence of p38 inhibitor SB203580. Conclusion: Increasing phosphate concentration stimulates erythrocyte membrane scrambling, an effect depending on extracellular but not intracellular Ca2+ concentration. It is hypothesized that suicidal erythrocyte death is triggered by complexed CaHPO4.

  12. Intracellular signal transduction by the extracellular calcium-sensing receptor of Xenopus melanotrope cells.

    NARCIS (Netherlands)

    Hurk, MJ van den; Cruijsen, P.M.; Schoeber, J.P.H.; Scheenen, W.J.J.M.; Roubos, E.W.; Jenks, B.G.

    2008-01-01

    The extracellular calcium-sensing receptor (CaR) is expressed in various types of endocrine pituitary cell, but the intracellular mechanism this G protein-coupled receptor uses in these cells is not known. In the present study we investigated possible intracellular signal transduction pathway(s)

  13. 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...

  14. Osteoclast cytosolic calcium, regulated by voltage-gated calcium channels and extracellular calcium, controls podosome assembly and bone resorption

    Science.gov (United States)

    Miyauchi, A.; Hruska, K. A.; Greenfield, E. M.; Duncan, R.; Alvarez, J.; Barattolo, R.; Colucci, S.; Zambonin-Zallone, A.; Teitelbaum, S. L.; Teti, A.

    1990-01-01

    The mechanisms of Ca2+ entry and their effects on cell function were investigated in cultured chicken osteoclasts and putative osteoclasts produced by fusion of mononuclear cell precursors. Voltage-gated Ca2+ channels (VGCC) were detected by the effects of membrane depolarization with K+, BAY K 8644, and dihydropyridine antagonists. K+ produced dose-dependent increases of cytosolic calcium ([Ca2+]i) in osteoclasts on glass coverslips. Half-maximal effects were achieved at 70 mM K+. The effects of K+ were completely inhibited by dihydropyridine derivative Ca2+ channel blocking agents. BAY K 8644 (5 X 10(-6) M), a VGCC agonist, stimulated Ca2+ entry which was inhibited by nicardipine. VGCCs were inactivated by the attachment of osteoclasts to bone, indicating a rapid phenotypic change in Ca2+ entry mechanisms associated with adhesion of osteoclasts to their resorption substrate. Increasing extracellular Ca2+ ([Ca2+]e) induced Ca2+ release from intracellular stores and Ca2+ influx. The Ca2+ release was blocked by dantrolene (10(-5) M), and the influx by La3+. The effects of [Ca2+]e on [Ca2+]i suggests the presence of a Ca2+ receptor on the osteoclast cell membrane that could be coupled to mechanisms regulating cell function. Expression of the [Ca2+]e effect on [Ca2+]i was similar in the presence or absence of bone matrix substrate. Each of the mechanisms producing increases in [Ca2+]i, (membrane depolarization, BAY K 8644, and [Ca2+]e) reduced expression of the osteoclast-specific adhesion structure, the podosome. The decrease in podosome expression was mirrored by a 50% decrease in bone resorptive activity. Thus, stimulated increases of osteoclast [Ca2+]i lead to cytoskeletal changes affecting cell adhesion and decreasing bone resorptive activity.

  15. Efficient neutrophil extracellular trap induction requires mobilization of both intracellular and extracellular calcium pools and is modulated by cyclosporine A.

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    Anurag Kumar Gupta

    Full Text Available Excessive or aberrant generation of neutrophil extracellular traps (NETs has recently become implicated in the underlying aetiology of a number of human pathologies including preeclampsia, systemic lupus erythromatosus, rheumatoid arthritis, auto-antibody induced small vessel vasculitis, coagulopathies such as deep vein thrombosis or pulmonary complications. These results imply that effective pharmacological therapeutic strategies will need to be developed to counter overt NETosis in these and other inflammatory disorders. As calcium flux is implicated in the generation of reactive oxygen species and histone citrullination, two key events in NETosis, we analysed the roles of both extra- and intracellular calcium pools and their modulation by pharmacological agents in the NETotic process in detail. Interleukin-8 (IL-8 was used as a physiological stimulus of NETosis. Our data demonstrate that efficient induction of NETosis requires mobilisation of both extracellular and intracellular calcium pools. Since modulation of the calcineurin pathway by cyclosporine A has been described in neutrophils, we investigated its influence on NETosis. Our data indicate that IL-8 induced NETosis is reduced by ascomycin and cyclosporine A, antagonists of the calcineurin pathway, but not following treatment with rapamycin, which utilizes the mTOR pathway. The action of the G protein coupled receptor phospholipase C pathway appears to be essential for the induction of NETs by IL-8, as NETosis was diminished by treatment with either pertussis toxin, a G-protein inhibitor, the phospholipase C inhibitor, U73122, or staurosporine, an inhibitor of protein kinase C. The data regarding the calcineurin antagonists, ascomycin and cyclosporine A, open the possibility to therapeutically suppress or modulate NETosis. They also provide new insight into the mechanism whereby such immune suppressive drugs render transplant patients susceptible to opportunistic fungal infections.

  16. Effect of free calcium concentration and ionic strength on alginate fouling in cross-flow membrane filtration

    NARCIS (Netherlands)

    Brink, van den P.; Zwijnenburg, A.; Smith, G.; Temmink, B.G.; Loosdrecht, van M.C.

    2009-01-01

    Extracellular polymeric substances (EPS) are generally negatively charged polymers. Membrane fouling in membrane bioreactors (MBRs) by EPS is therefore influenced by the water chemistry of the mixed liquor (calcium concentration, foulant concentration and ionic strength). We used alginate as a model

  17. Effect of free calcium concentration and ionic strength on alginate fouling in cross-flow membrane filtration

    NARCIS (Netherlands)

    Brink, van den P.; Zwijnenburg, A.; Smith, G.; Temmink, B.G.; Loosdrecht, van M.C.

    2009-01-01

    Extracellular polymeric substances (EPS) are generally negatively charged polymers. Membrane fouling in membrane bioreactors (MBRs) by EPS is therefore influenced by the water chemistry of the mixed liquor (calcium concentration, foulant concentration and ionic strength). We used alginate as a model

  18. Calcium carbonate mineralization: involvement of extracellular polymeric materials isolated from calcifying bacteria.

    Science.gov (United States)

    Ercole, Claudia; Bozzelli, Paola; Altieri, Fabio; Cacchio, Paola; Del Gallo, Maddalena

    2012-08-01

    This study highlights the role of specific outer bacterial structures, such as the glycocalix, in calcium carbonate crystallization in vitro. We describe the formation of calcite crystals by extracellular polymeric materials, such as exopolysaccharides (EPS) and capsular polysaccharides (CPS) isolated from Bacillus firmus and Nocardia calcarea. Organic matrices were isolated from calcifying bacteria grown on synthetic medium--in the presence or absence of calcium ions--and their effect on calcite precipitation was assessed. Scanning electron microscopy observations and energy dispersive X-ray spectrometry analysis showed that CPS and EPS fractions were involved in calcium carbonate precipitation, not only serving as nucleation sites but also through a direct role in crystal formation. The utilization of different synthetic media, with and without addition of calcium ions, influenced the biofilm production and protein profile of extracellular polymeric materials. Proteins of CPS fractions with a molecular mass between 25 and 70 kDa were overexpressed when calcium ions were present in the medium. This higher level of protein synthesis could be related to the active process of bioprecipitation.

  19. Extracellular calcium-sensing receptor: structural and functional features and association with diseases

    Directory of Open Access Journals (Sweden)

    Hauache O.M.

    2001-01-01

    Full Text Available The recently cloned extracellular calcium-sensing receptor (CaR is a G protein-coupled receptor that plays an essential role in the regulation of extracellular calcium homeostasis. This receptor is expressed in all tissues related to this control (parathyroid glands, thyroid C-cells, kidneys, intestine and bones and also in tissues with apparently no role in the maintenance of extracellular calcium levels, such as brain, skin and pancreas. The CaR amino acid sequence is compatible with three major domains: a long and hydrophilic aminoterminal extracellular domain, where most of the activating and inactivating mutations described to date are located and where the dimerization process occurs, and the agonist-binding site is located, a hydrophobic transmembrane domain involved in the signal transduction mechanism from the extracellular domain to its respective G protein, and a carboxyterminal intracellular tail, with a well-established role for cell surface CaR expression and for signal transduction. CaR cloning was immediately followed by the association of genetic human diseases with inactivating and activating CaR mutations: familial hypocalciuric hypercalcemia and neonatal severe hyperparathyroidism are caused by CaR-inactivating mutations, whereas autosomal dominant hypoparathyroidism is secondary to CaR-activating mutations. Finally, we will comment on the development of drugs that modulate CaR function by either activating (calcimimetic drugs or antagonizing it (calcilytic drugs, and on their potential therapeutic implications, such as medical control of specific cases of primary and uremic hyperparathyroidism with calcimimetic drugs and a potential treatment for osteoporosis with a calcilytic drug.

  20. Aristoyunnolin H attenuates extracellular matrix secretion in cardiac fibroblasts by inhibiting calcium influx.

    Science.gov (United States)

    Chen, Shao-Rui; Zhang, Wen-Ping; Bao, Jing-Mei; Cheng, Zhong-Bin; Yin, Sheng

    2017-01-01

    Aristoyunnolin H is a novel aristophyllene sesquiterpenoid isolated from the traditional Chinese medicine Aristolochia yunnanensis Franch. The present research was designed to explore the anti-fibrotic effects of aristoyunnolin H in adult rat cardiac fibroblasts (CFs) stimulated with angiotensin II (Ang II). Western blot analysis data showed that aristoyunnolin H reduced the upregulation of fibronectin (FN), connective tissue growth factor and collagen I(Col I) production induced by Ang II in CFs. By studying the dynamic intracellular changes of Ca(2+), we further found that while aristoyunnolin H relieved the calcium influx, it has no effect on intracellular calcium store release. Meanwhile, aristoyunnolin H also inhibited the Ang II-stimulated phosphorylation of Ca(2+)/calmodulin-dependent protein kinase II. In conclusion, aristoyunnolin H may attenuate extracellular matrix secretion in vitro by inhibiting Ang II-induced calcium signaling.

  1. Extracellular Calcium Modulates Chondrogenic and Osteogenic Differentiation of Human Adipose-Derived Stem Cells: A Novel Approach for Osteochondral Tissue Engineering Using a Single Stem Cell Source.

    Science.gov (United States)

    Mellor, Liliana F; Mohiti-Asli, Mahsa; Williams, John; Kannan, Arthi; Dent, Morgan R; Guilak, Farshid; Loboa, Elizabeth G

    2015-09-01

    We have previously shown that elevating extracellular calcium from a concentration of 1.8 to 8 mM accelerates and increases human adipose-derived stem cell (hASC) osteogenic differentiation and cell-mediated calcium accretion, even in the absence of any other soluble osteogenic factors in the culture medium. However, the effects of elevated calcium on hASC chondrogenic differentiation have not been reported. The goal of this study was to determine the effects of varied calcium concentrations on chondrogenic differentiation of hASC. We hypothesized that exposure to elevated extracellular calcium (8 mM concentration) in a chondrogenic differentiation medium (CDM) would inhibit chondrogenesis of hASC when compared to basal calcium (1.8 mM concentration) controls. We further hypothesized that a full osteochondral construct could be engineered by controlling local release of calcium to induce site-specific chondrogenesis and osteogenesis using only hASC as the cell source. Human ASC was cultured as micromass pellets in CDM containing transforming growth factor-β1 and bone morphogenetic protein 6 for 28 days at extracellular calcium concentrations of either 1.8 mM (basal) or 8 mM (elevated). Our findings indicated that elevated calcium induced osteogenesis and inhibited chondrogenesis in hASC. Based on these findings, stacked polylactic acid nanofibrous scaffolds containing either 0% or 20% tricalcium phosphate (TCP) nanoparticles were electrospun and tested for site-specific chondrogenesis and osteogenesis. Histological assays confirmed that human ASC differentiated locally to generate calcified tissue in layers containing 20% TCP, and cartilage in the layers with no TCP when cultured in CDM. This is the first study to report the effects of elevated calcium on chondrogenic differentiation of hASC, and to develop osteochondral nanofibrous scaffolds using a single cell source and controlled calcium release to induce site-specific differentiation. This approach

  2. Influence of calcium in extracellular DNA mediated bacterial aggregation and biofilm formation.

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    Theerthankar Das

    Full Text Available Calcium (Ca(2+ has an important structural role in guaranteeing the integrity of the outer lipopolysaccharide layer and cell walls of bacterial cells. Extracellular DNA (eDNA being part of the slimy matrix produced by bacteria promotes biofilm formation through enhanced structural integrity of the matrix. Here, the concurrent role of Ca(2+ and eDNA in mediating bacterial aggregation and biofilm formation was studied for the first time using a variety of bacterial strains and the thermodynamics of DNA to Ca(2+ binding. It was found that the eDNA concentrations under both planktonic and biofilm growth conditions were different among bacterial strains. Whilst Ca(2+ had no influence on eDNA release, presence of eDNA by itself favours bacterial aggregation via attractive acid-base interactions in addition, its binding with Ca(2+ at biologically relevant concentrations was shown further increase in bacterial aggregation via cationic bridging. Negative Gibbs free energy (ΔG values in iTC data confirmed that the interaction between DNA and Ca(2+ is thermodynamically favourable and that the binding process is spontaneous and exothermic owing to its highly negative enthalpy. Removal of eDNA through DNase I treatment revealed that Ca(2+ alone did not enhance cell aggregation and biofilm formation. This discovery signifies the importance of eDNA and concludes that existence of eDNA on bacterial cell surfaces is a key facilitator in binding of Ca(2+ to eDNA thereby mediating bacterial aggregation and biofilm formation.

  3. Serum Calcium Concentration in Ethylene Glycol Poisoning.

    Science.gov (United States)

    Hodgman, Michael; Marraffa, Jeanna M; Wojcik, Susan; Grant, William

    2017-06-01

    The diagnosis of ethylene glycol intoxication can be challenging. Definitive testing for ethylene glycol is not readily available and clinical decisions are often based on clinical suspicion and the results of more readily available tests. One of these findings is hypocalcemia, presumable through complexation with the ethylene glycol metabolite oxalate. We performed a retrospective review of all patients admitted to a tertiary care hospital between 2005 and 2013 with laboratory confirmed ethylene glycol intoxication. Serum calcium on presentation was compared to blood gas pH on presentation as well as presentation serum bicarbonate. We did not find any relationship between calcium and serum pH either by linear regression or when dichotomized by pH ≥ or ethylene glycol poisoning, even in acidotic patients.

  4. Lowering extracellular chloride concentration alters outer hair cell shape.

    Science.gov (United States)

    Cecola, R P; Bobbin, R P

    1992-08-01

    In general, increasing external K+ concentration, as well as exposure to hypotonic medium, induces a shortening of outer hair cells (OHCs) accompanied by an increase in width and volume. One possible mechanism suggested for these changes is a movement of Cl- and/or water across the cell membrane. We therefore examined the role of Cl- in OHC volume maintenance by testing the effect of decreasing extracellular Cl- concentration on OHC length and shape. In addition, the effect of hypotonic medium was examined. OHCs were isolated from guinea pig cochleae, mechanically dissociated and dispersed, and placed in a modified Hanks balanced salt solution (HBS). Exposing the cells to a Cl(-)-free HBS produced an initial shortening, which was rapidly followed by an increase in length. After about 9 min of exposure to Cl(-)-free HBS, the cells appeared to lose all water and collapsed. Upon return to normal HBS, the OHCs returned to their normal shape. We speculate that the collapse of the OHCs may be due to the loss of intracellular Cl-, which, in turn, resulted in the loss of intracellular K+ and water. The results indicate that Cl- contributes greatly to the maintenance of OHC volume. In addition, we confirmed that isolated OHCs swell in hypotonic medium and maintain their swollen state until returned to normal medium. The mechanism for maintenance of the swollen state is unknown.

  5. Ubiquitylation functions in the calcium carbonate biomineralization in the extracellular matrix.

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    Dong Fang

    Full Text Available Mollusks shell formation is mediated by matrix proteins and many of these proteins have been identified and characterized. However, the mechanisms of protein control remain unknown. Here, we report the ubiquitylation of matrix proteins in the prismatic layer of the pearl oyster, Pinctada fucata. The presence of ubiquitylated proteins in the prismatic layer of the shell was detected with a combination of western blot and immunogold assays. The coupled ubiquitins were separated and identified by Edman degradation and liquid chromatography/mass spectrometry (LC/MS. Antibody injection in vivo resulted in large amounts of calcium carbonate randomly accumulating on the surface of the nacreous layer. These ubiquitylated proteins could bind to specific faces of calcite and aragonite, which are the two main mineral components of the shell. In the in vitro calcium carbonate crystallization assay, they could reduce the rate of calcium carbonate precipitation and induce the calcite formation. Furthermore, when the attached ubiquitins were removed, the functions of the EDTA-soluble matrix of the prismatic layer were changed. Their potency to inhibit precipitation of calcium carbonate was decreased and their influence on the morphology of calcium carbonate crystals was changed. Taken together, ubiquitylation is involved in shell formation. Although the ubiquitylation is supposed to be involved in every aspect of biophysical processes, our work connected the biomineralization-related proteins and the ubiquitylation mechanism in the extracellular matrix for the first time. This would promote our understanding of the shell biomineralization and the ubiquitylation processes.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    death and could be a novel cancer treatment. This study aims at understanding the relationship between applied electric field, calcium concentration, ATP depletion and efficacy. METHODS: In three human cell lines--H69 (small-cell lung cancer), SW780 (bladder cancer), and U937 (leukaemia), viability...... was observed with fluorescence confocal microscopy of quinacrine-labelled U937 cells. RESULTS: Both H69 and SW780 cells showed dose-dependent (calcium concentration and electric field) decrease in intracellular ATP (p...-dependently reduced cell survival and intracellular ATP. Increasing extracellular calcium allows the use of a lower electric field. GENERAL SIGNIFICANCE: This study supports the use of calcium electroporation for treatment of cancer and possibly lowering the applied electric field in future trials....

  7. Aggregation of Phosphoinositides at Phisiological Calcium Concentrations

    Science.gov (United States)

    Kazadi Badiambile, Adolphe; Forstner, Martin B.

    2012-02-01

    Phosphoinositides play a crucial role in many cellular functions such as calcium signaling, endocytosis, exocytosis and the targeting of proteins to specific membrane sites. To maintain functional specificity, it has been suggested that phosphoinositides are spatially organized in ``pools'' in the cellular plasma membrane. A possible mechanism that could induce and regulate such organization of phosphoinositides is their interaction with Ca2+ ions. Understanding the physicochemical mechanism that can regulate membrane structure is a crucial step in the development of adaptive biomimetic membrane systems. Using Langmuir monolayers, we investigated the effect of bivalent calcium and magnesium cations on the surface pressure-area/lipid isotherm of monolayers of phosphatidylinositol (PI), phosphatidylinositol bisphosphate (PIP2) and dioleoylphosphatidylglycerol (DOPG) and dipalmitoylphosphatidylcholine (DPPC). It is found that the decrease of area per lipid, i.e. the increase in aggregation, is dependent on both the lipid's head group charge, the bivalent cation and temperature. However, electrostatics are not sufficient to account for all experimental observations. Thus additional interactions between ions and phosphoinositides need to be considered.

  8. Heterotrimeric G protein participated in modulation of cytoplasmic calcium concentration in pollen cells

    Institute of Scientific and Technical Information of China (English)

    SHANG Zhonglin; MA Ligeng; WANG Xuechen; SUN Daye

    2003-01-01

    Cytoplasmic free calcium concentration([Ca2+]c) in pollen cells of Lilium daviddi is measured with confocal laser scanning microscopy to investigate the effect of heterotrimeric G protein (G protein) on [Ca2+]c and the possible signal transduction pathway of G protein triggering cellular calcium signal. After application, cholera toxin (CTX), an agonist of G protein, triggers a transient increase of [Ca2+]c in pollen cells, and evokes a spatial-temporal characteristic calcium dynamics; while pertussis toxin (PTX), a G protein antagonist, leads to the decrease of [Ca2+]c. Both L-type Ca2+ channel blocker verapamil and inhibitor of IP3 receptor heparin inhibit CTX-induced [Ca2+]c increase. The results show that G protein may play a role in the modulation of [Ca2+]c through enhancing the extracellular Ca2+ influx and releasing of Ca2+ from intracellular stores.

  9. Serum calcium concentration and prostate cancer risk: a multicenter study.

    Science.gov (United States)

    Salem, Sepehr; Hosseini, Mostafa; Allameh, Farzad; Babakoohi, Shahab; Mehrsai, Abdolrasoul; Pourmand, Gholamreza

    2013-01-01

    This study sought to further evaluate the possible effects of serum calcium level on prostate cancer (PC) risk, with considering the age, body mass index (BMI), and sex steroid hormones. Using data from a prospective multicenter study, serum calcium concentration, as well as thorough demographic and medical characteristics, were determined in 194 cases with newly diagnosed, clinicopathologically confirmed PC and 317 controls, without any malignant disease, admitted to the same network of hospitals. Serum total and ionized calcium levels were categorized into tertiles. Multivariate logistic regression model was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) after adjustment for major potential confounders, including age, BMI, smoking, alcohol, education, occupation, marital status, family history of PC, and sex hormones level. The mean serum calcium level (±SD) in case and control groups was 9.22 (±0.46) mg/dl and 9.48 (±0.51) mg/dl, respectively (P < 0.001). After adjustment for mentioned confounders, a significant trend of decreasing risk was found for serum total calcium concentration (OR = 0.27, 95% CI = 0.12-0.59, comparing the highest with the lowest tertile) and ionized calcium (OR = 0.25, 95% CI = 0.10-0.58). An increase of 1 mg/dl in serum calcium level was associated with a significant decrease in PC risk (OR = 0.52; 95% CI = 0.34-0.76). Our findings reveal the inverse association between serum total and ionized concentrations and PC risk, which supports the hypothesis that calcium may protect against PC. Furthermore, no evidence was found regarding age, BMI, and sex steroid hormones to modify the association between serum calcium and PC risk.

  10. Morphological Investigation of Calcium Carbonate during Ammonification-Carbonization Process of Low Concentration Calcium Solution

    Directory of Open Access Journals (Sweden)

    Huaigang Cheng

    2014-01-01

    Full Text Available Ultrafine calcium carbonate is a widely used cheap additive. The research is conducted in low degree supersaturation solution in order to study the polymorphic phases’ change and its factors of the calcium carbonate precipitate in the ammonification-carbonization process of the solution with calcium. Fine particles of calcium carbonate are made in the solution containing 0.015 mol/L of Ca2+. Over 98% of the calcium carbonate precipitate without ammonification resembles the morphology of calcite, while the introduction of ammonia can benefit the formation of vaterite. It was inferred that the main cause should be serious partial oversaturation or steric effects. Ammonia also helps to form the twin spherical calcium carbonate. However, particles formed in the process of ammonification-carbonization in solution with low concentration degree of calcium are not even with a scale of the particle diameter from 5 to 12 μm. Inorganic salts, alcohol, or organic acid salts have significant controlling effect on the particle diameter of calcium carbonate and can help to decrease the particle diameter to about 3 μm. Anionic surfactants can prevent the conglobation of calcium carbonate particles and shrink its diameter to 500 nm–1 μm.

  11. Modulation by extracellular pH of low- and high-voltage-activated calcium currents of rat thalamic relay neurons.

    Science.gov (United States)

    Shah, M J; Meis, S; Munsch, T; Pape, H C

    2001-03-01

    The effects of changes in the extracellular pH (pH(o)) on low-voltage- (LVA) and high-voltage- (HVA) activated calcium currents of acutely isolated relay neurons of the ventrobasal thalamic complex (VB) were examined using the whole cell patch-clamp technique. Modest extracellular alkalinization (pH 7.3 to 7.7) reversibly enlarged LVA calcium currents by 18.6 +/- 3.2% (mean +/- SE, n = 6), whereas extracellular acidification (pH 7.3 to 6.9) decreased the current by 24.8 +/- 3.1% (n = 9). Normalized current amplitudes (I/I(7.3)) fitted as a function of pH(o) revealed an apparent pK(a) of 6.9. Both, half-maximal activation voltage and steady-state inactivation were significantly shifted to more negative voltages by 2-4 mV on extracellular alkalinization and to more positive voltages by 2-3 mV on extracellular acidification, respectively. Recovery from inactivation of LVA calcium currents was not significantly affected by changes in pH(o). In contrast, HVA calcium currents were less sensitive to changes in pH(o). Although extracellular alkalinization increased maximal HVA current by 6.0 +/- 2.0% (n = 7) and extracellular acidification decreased it by 11.9 +/- 0.02% (n = 11), both activation and steady-state inactivation were only marginally affected by the moderate changes in pH(o) used in the present study. The results show that calcium currents of thalamic relay neurons exhibit different pH(o) sensitivity. Therefore activity-related extracellular pH transients might selectively modulate certain aspects of the electrogenic behavior of thalamic relay neurons.

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  13. Extracellular matrix stiffness modulates VEGF calcium signaling in endothelial cells: individual cell and population analysis.

    Science.gov (United States)

    Derricks, Kelsey E; Trinkaus-Randall, Vickery; Nugent, Matthew A

    2015-09-01

    Vascular disease and its associated complications are the number one cause of death in the Western world. Both extracellular matrix stiffening and dysfunctional endothelial cells contribute to vascular disease. We examined endothelial cell calcium signaling in response to VEGF as a function of extracellular matrix stiffness. We developed a new analytical tool to analyze both population based and individual cell responses. Endothelial cells on soft substrates, 4 kPa, were the most responsive to VEGF, whereas cells on the 125 kPa substrates exhibited an attenuated response. Magnitude of activation, not the quantity of cells responding or the number of local maximums each cell experienced distinguished the responses. Individual cell analysis, across all treatments, identified two unique cell clusters. One cluster, containing most of the cells, exhibited minimal or slow calcium release. The remaining cell cluster had a rapid, high magnitude VEGF activation that ultimately defined the population based average calcium response. Interestingly, at low doses of VEGF, the high responding cell cluster contained smaller cells on average, suggesting that cell shape and size may be indicative of VEGF-sensitive endothelial cells. This study provides a new analytical tool to quantitatively analyze individual cell signaling response kinetics, that we have used to help uncover outcomes that are hidden within the average. The ability to selectively identify highly VEGF responsive cells within a population may lead to a better understanding of the specific phenotypic characteristics that define cell responsiveness, which could provide new insight for the development of targeted anti- and pro-angiogenic therapies.

  14. High concentration of calcium ions in Golgi apparatus

    Institute of Scientific and Technical Information of China (English)

    XUESHAOBAI; M.ROBERTNICOUD; 等

    1994-01-01

    The interphase NIH3T3 cells were vitally fluorescentstained with calcium indicator fluo-3 and Glogi probe C6-NBD-ceramide,and then the single cells were examined by laser scanning confocal microscopy(LSCFM) for subcellular distributions of Ca2+ and the location of Golgi apparatus.In these cells,the intracellular Ca2+ were found to be highly concentrated in the Golgi apparatus.The changes of distribution of cytosolic high Ca2+ region and the Golgi apparatus coincided with the cell cycle phase.In calcium free medium,when the plasma membrane of the cells which had been loaded with fluo-3/AM were permeated by digitonin,the fluorescence of the Golgi region decreased far less than that of the cytosol.Our results indicated that the Glogi lumen retained significantly high concentration of free calcium.

  15. Extracellular ATP induces the release of calcium from intracellular stores without the activation of protein kinase C in Swiss 3T6 mouse fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, F.A.; Rozengurt, E.; Heppel, L.A. (Cornell Univ., Ithaca, NY (USA))

    1989-06-01

    Exposure of Swiss 3T6 mouse fibroblasts to extracellular ATP stimulated the formation of inositol phosphates and mobilized intracellular calcium. The mobilization of intracellular calcium was verified by imaging of fura-2 fluorescence in individual cells and by monitoring the efflux of {sup 45}Ca{sup 2+} from preloaded cells. However, the authors found no activation of protein kinase C as measured by phosphorylation of an 80-kDa acidic protein and by transmodulation of the receptor for epidermal growth factor. A careful examination of the kinetics of the phosphorylation reaction (from 30 sec to 10 min) revealed no activation of protein kinase C by extracellular ATP at any time. The lack of activation of protein kinase C was demonstrated even when a concentration of ATP 10-fold higher than that required to give a strong Ca{sup 2+} signal was used. Extracellular ATP did not inhibit protein kinase C activation by fetal bovine serum, platelet-derived growth factor, or phorbol esters. The effects of ATP were also produced by UTP but not by ADP, AMP, or adenosine. These findings demonstrate that it is possible to induce the mobilization of intracellular calcium by an inositol phosphate-mediated pathway without the activation of protein kinase C.

  16. GLUCOSE-CONCENTRATION IN SUBCUTANEOUS EXTRACELLULAR-SPACE

    NARCIS (Netherlands)

    SCHMIDT, FJ; SLUITER, WJ; SCHOONEN, AJM

    1993-01-01

    OBJECTIVE- To compare the subcutaneous glucose sensor measurements with two reference methods. Previous studies provide conflicting findings about the real glucose concentrations in subcutaneous tissue. Some suggest substantially lower concentration, whereas others measure proportionally higher gluc

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  18. Calcium and magnesium concentrations in mature human milk: influence of calcium intake, age and socioeconomic level.

    Science.gov (United States)

    Vítolo, M R; Valente Soares, L M; Carvalho, E B; Cardoso, C B

    2004-03-01

    Concentrations of calcium and magnesium were measured in mature milk, collected between 30 and 90 days after childbirth, from a group of 90 mothers between 14 and 39 years of age, exclusively breastfeeding. The group was divided into three sub-groups: low socioeconomic-level adolescents (LSAd), low socioeconomic-level adults (LSA), and high socioeconomic-level adults (HSA). Each mother's nutritional status was determined using the body-mass index (BMI) and her eating habits, obtained on the basis of a 24-h dietary recall. Adolescent and adult mothers in the low socioeconomic-level group had lower average calcium intake (LSAd = 618.4 +/- 555.2 mg and LSA = 679.4 +/- 411.4 mg) than adult mothers in the higher socioeconomic-level group (853.6 +/- 415.5 mg). The average concentration of calcium in the adolescent mothers' milk (LSAd) was significantly lower (5.30 +/- 1.42 mmol Ca/L, P = 0.01) than that of the two adult groups (LSA = 5.82 +/- 1.55 mmol Ca/L and HSA = 6.40 mmol Ca/L). The average magnesium concentrations for all groups did not show significant differences (LSAd = 1.06 +/- 0.18, LSA = 1.16 +/- 0.23 and HSA = 1.11 +/- 0.23 mmol Mg/L, for P= 0.16). These results indicate that magnesium concentrations in mature human milk do not seem to depend on maternal nutritional status. The condition of adolescence, however, associated with lower calcium intake by the mother, resulted in lower calcium concentrations in the milk secreted when compared to that of adult mothers.

  19. Extracellular calcium modulates persistent sodium current-dependent burst-firing in hippocampal pyramidal neurons.

    Science.gov (United States)

    Su, H; Alroy, G; Kirson, E D; Yaari, Y

    2001-06-15

    The generation of high-frequency spike bursts ("complex spikes"), either spontaneously or in response to depolarizing stimuli applied to the soma, is a notable feature in intracellular recordings from hippocampal CA1 pyramidal cells (PCs) in vivo. There is compelling evidence that the bursts are intrinsically generated by summation of large spike afterdepolarizations (ADPs). Using intracellular recordings in adult rat hippocampal slices, we show that intrinsic burst-firing in CA1 PCs is strongly dependent on the extracellular concentration of Ca(2+) ([Ca(2+)](o)). Thus, lowering [Ca(2+)](o) (by equimolar substitution with Mn(2+) or Mg(2+)) induced intrinsic bursting in nonbursters, whereas raising [Ca(2+)](o) suppressed intrinsic bursting in native bursters. The induction of intrinsic bursting by low [Ca(2+)](o) was associated with enlargement of the spike ADP. Low [Ca(2+)](o)-induced intrinsic bursts and their underlying ADPs were suppressed by drugs that reduce the persistent Na(+) current (I(NaP)), indicating that this current mediates the slow burst depolarization. Blocking Ca(2+)-activated K(+) currents with extracellular Ni(2+) or intracellular chelation of Ca(2+) did not induce intrinsic bursting. This and other evidence suggest that lowering [Ca(2+)](o) may induce intrinsic bursting by augmenting I(NaP). Because repetitive neuronal activity in the hippocampus is associated with marked decreases in [Ca(2+)](o), the regulation of intrinsic bursting by extracellular Ca(2+) may provide a mechanism for preferential recruitment of this firing mode during certain forms of hippocampal activation.

  20. EFFECTS OF PDGF-BB ON INTRACELLULAR CALCIUM CONCENTRATION AND PROLIFERATION IN CULTURED GLOMERULAR MESANGIAL CELLS

    Institute of Scientific and Technical Information of China (English)

    WEN Li-ping; ZHANG Chong; BIAN Fan; ZOU Jun; JIANG Geng-ru; ZHU Han-wei

    2006-01-01

    Objective To investigate the relationship between the alteration of intracellular calcium concentration and proliferation in cultured glomerular mesangial cells. Methods Rat mesangial cells were cultured.Intracellular calcium concentrations were measured by confocal Laser Scanning Microscopy and Fura-3 fluorescence dyeing techniques. Cell growth was measured by MTT assay. Results PDGF-BB increased intracellular calcium concentrations in a dose-dependent manner, and at the same time promote the proliferation of mesangial cells. After preincubation with calcium channel blocker nifedipine or angiotensin converting enzyme inhibitor captopril, both the increase of intracellular calcium concentrations and cell proliferations induced by PDGF-BB were inhibited. Tripterigium Wilfordii Glycosides (TMG) significantly inhibited the mesangial cell proliferations, but it had no significant effect on intracellular calcium concentrations. Conclusion There was a positive relationship between the elevation of intracellular calcium concentration and cell proliferation in glomerular mesangial cells, but the increase of in- tracellular calcium concentrations wasn't the only way for proliferation.

  1. Understanding spatial and temporal patterning of astrocyte calcium transients via interactions between network transport and extracellular diffusion

    Science.gov (United States)

    Shtrahman, E.; Maruyama, D.; Olariu, E.; Fink, C. G.; Zochowski, M.

    2017-02-01

    Astrocytes form interconnected networks in the brain and communicate via calcium signaling. We investigate how modes of coupling between astrocytes influence the spatio-temporal patterns of calcium signaling within astrocyte networks and specifically how these network interactions promote coordination within this group of cells. To investigate these complex phenomena, we study reduced cultured networks of astrocytes and neurons. We image the spatial temporal patterns of astrocyte calcium activity and quantify how perturbing the coupling between astrocytes influences astrocyte activity patterns. To gain insight into the pattern formation observed in these cultured networks, we compare the experimentally observed calcium activity patterns to the patterns produced by a reduced computational model, where we represent astrocytes as simple units that integrate input through two mechanisms: gap junction coupling (network transport) and chemical release (extracellular diffusion). We examine the activity patterns in the simulated astrocyte network and their dependence upon these two coupling mechanisms. We find that gap junctions and extracellular chemical release interact in astrocyte networks to modulate the spatiotemporal patterns of their calcium dynamics. We show agreement between the computational and experimental findings, which suggests that the complex global patterns can be understood as a result of simple local coupling mechanisms.

  2. Intracellular calcium movements of boar spermatozoa during 'in vitro' capacitation and subsequent acrosome exocytosis follow a multiple-storage place, extracellular calcium-dependent model.

    Science.gov (United States)

    Yeste, M; Fernández-Novell, J M; Ramió-Lluch, L; Estrada, E; Rocha, L G; Cebrián-Pérez, J A; Muiño-Blanco, T; Concha, I I; Ramírez, A; Rodríguez-Gil, J E

    2015-07-01

    This work analysed intracellular calcium stores of boar spermatozoa subjected to 'in vitro' capacitation (IVC) and subsequent progesterone-induced acrosome exocytosis (IVAE). Intracellular calcium was analysed through two calcium markers with different physico-chemical properties, Fluo-3 and Rhod-5N. Indicative parameters of IVC and IVAE were also evaluated. Fluo-3 was located at both the midpiece and the whole head. Rhod-5N was present at the sperm head. This distribution did not change in any of the assayed conditions. Induction of IVC was concomitant with an increase in both head and midpiece Ca(2+) signals. Additionally, while IVC induction was concurrent with a significant (p Fluo-3 marking at the midpiece increased after progesterone addition to sperm cells incubated in a medium without Ca(2+) . The simultaneous addition of progesterone with the calcium chelant EGTA inhibited IVAE, and this was accompanied by a significant (p < 0.05) decrease in the intensity of progesterone Ca(2+) -induced peak, O2 consumption and ATP levels. Our results suggest that boar spermatozoa present different calcium deposits with a dynamic equilibrium among them and with the extracellular environment. Additionally, the modulation role of the intracellular calcium in spermatozoa function seems to rely on its precise localization in boar spermatozoa. © 2015 American Society of Andrology and European Academy of Andrology.

  3. The extracellular calcium-sensing receptor is required for cholecystokinin secretion in response to L-phenylalanine in acutely isolated intestinal I cells.

    Science.gov (United States)

    Liou, Alice P; Sei, Yoshitatsu; Zhao, Xilin; Feng, Jianying; Lu, Xinping; Thomas, Craig; Pechhold, Susanne; Raybould, Helen E; Wank, Stephen A

    2011-04-01

    The extracellular calcium-sensing receptor (CaSR) has recently been recognized as an L-amino acid sensor and has been implicated in mediating cholecystokinin (CCK) secretion in response to aromatic amino acids. We investigated whether direct detection of L-phenylalanine (L-Phe) by CaSR results in CCK secretion in the native I cell. Fluorescence-activated cell sorting of duodenal I cells from CCK-enhanced green fluorescent protein (eGFP) transgenic mice demonstrated CaSR gene expression. Immunostaining of fixed and fresh duodenal tissue sections confirmed CaSR protein expression. Intracellular calcium fluxes were CaSR dependent, stereoselective for L-Phe over D-Phe, and responsive to type II calcimimetic cinacalcet in CCK-eGFP cells. Additionally, CCK secretion by an isolated I cell population was increased by 30 and 62% in response to L-Phe in the presence of physiological (1.26 mM) and superphysiological (2.5 mM) extracellular calcium concentrations, respectively. While the deletion of CaSR from CCK-eGFP cells did not affect basal CCK secretion, the effect of L-Phe or cinacalcet on intracellular calcium flux was lost. In fact, both secretagogues, as well as superphysiological Ca(2+), evoked an unexpected 20-30% decrease in CCK secretion compared with basal secretion in CaSR(-/-) CCK-eGFP cells. CCK secretion in response to KCl or tryptone was unaffected by the absence of CaSR. The present data suggest that CaSR is required for hormone secretion in the specific response to L-Phe by the native I cell, and that a receptor-mediated mechanism may inhibit hormone secretion in the absence of a fully functional CaSR.

  4. Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.

    2011-01-01

    The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

  5. Cinacalcet, dialysate calcium concentration, and cardiovascular events in the EVOLVE trial.

    Science.gov (United States)

    Pun, Patrick H; Abdalla, Safa; Block, Geoffrey A; Chertow, Glenn M; Correa-Rotter, Ricardo; Dehmel, Bastian; Drüeke, Tilman B; Floege, Jürgen; Goodman, William G; Herzog, Charles A; London, Gerard M; Mahaffey, Kenneth W; Moe, Sharon M; Parfrey, Patrick S; Wheeler, David C; Middleton, John P

    2016-07-01

    Among patients receiving hemodialysis, abnormalities in calcium regulation have been linked to an increased risk of cardiovascular events. Cinacalcet lowers serum calcium concentrations through its effect on parathyroid hormone secretion and has been hypothesized to reduce the risk of cardiovascular events. In observational cohort studies, prescriptions of low dialysate calcium concentration and larger observed serum-dialysate calcium gradients have been associated with higher risks of in-dialysis facility or peri-dialytic sudden cardiac arrest. We performed this study to examine the risks associated with dialysate calcium and serum-dialysate gradients among participants in the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events (EVOLVE) trial. In EVOLVE, 3883 hemodialysis patients were randomized 1:1 to cinacalcet or placebo. Dialysate calcium was administered at the discretion of treating physicians. We examined whether baseline dialysate calcium concentration or the serum-dialysate calcium gradient modified the effect of cinacalcet on the following adjudicated endpoints: (1) primary composite endpoint (death or first non-fatal myocardial infarction, hospitalization for unstable angina, heart failure, or peripheral vascular event); (2) cardiovascular death; and (3) sudden death. In EVOLVE, use of higher dialysate calcium concentrations was more prevalent in Europe and Latin America compared with North America. There was a significant fall in serum calcium concentration in the cinacalcet group; dialysate calcium concentrations were changed infrequently in both groups. There was no association between baseline dialysate calcium concentration or serum-dialysate calcium gradient and the endpoints examined. Neither the baseline dialysate calcium nor the serum-dialysate calcium gradient significantly modified the effects of cinacalcet on the outcomes examined. The effects of cinacalcet on cardiovascular death and major cardiovascular events

  6. Free calcium concentration in brain nerve endings of spontaneously hypertensive rats

    Energy Technology Data Exchange (ETDEWEB)

    Orlov, S.N.; Pokudin, N.I.; Kravstov, G.M.; Postnov, Yu.V.; Okun' , I.M.; Shukanova, N.A.; Rakovich, A.A.; Aksentsev, S.L.; Konev, S.V.

    1987-10-01

    The frequency of neurotransmitter release from the synaptic vesicles of nerve endings by exocytosis depends primarily on the free calcium concentration in the cytoplasm which is controlled by calcium transporting and calcium binding systems. In this paper, in an attempt to determine the state of these systems in primary hypertension and the effects of neurotransmitter release on the increased resistance in the peripheral circulatory system, the authors study the exchange, uptake, and concentration of calcium 45 cations by synaptosomes.

  7. Effects of calcium at toxic concentrations of cadmium in plants.

    Science.gov (United States)

    Huang, Danlian; Gong, Xiaomin; Liu, Yunguo; Zeng, Guangming; Lai, Cui; Bashir, Hassan; Zhou, Lu; Wang, Dafei; Xu, Piao; Cheng, Min; Wan, Jia

    2017-05-01

    This review provides new insight that calcium plays important roles in plant growth, heavy metal accumulation and translocation, photosynthesis, oxidative damage and signal transduction under cadmium stress. Increasing heavy metal pollution problems have raised word-wide concerns. Cadmium (Cd), being a highly toxic metal, poses potential risks both to ecosystems and human health. Compared with conventional technologies, phytoremediation, being cost-efficient, highly stable and environment-friendly, is believed to be a promising green technology for Cd decontamination. However, Cd can be easily taken up by plants and may cause severe phytotoxicity to plants, thus limiting the efficiency of phytoremediation. Various researches are being done to investigate the effects of exogenous substances on the mitigation of Cd toxicity to plants. Calcium (Ca) is an essential plant macronutrient that involved in various plant physiological processes, such as plant growth and development, cell division, cytoplasmic streaming, photosynthesis and intracellular signaling transduction. Due to the chemical similarity between Ca and Cd, Ca may mediate Cd-induced physiological or metabolic changes in plants. Recent studies have shown that Ca could be used as an exogenous substance to protect plants against Cd stress by the alleviation of growth inhibition, regulation of metal uptake and translocation, improvement of photosynthesis, mitigation of oxidative damages and the control of signal transduction in the plants. The effects of Ca on toxic concentrations of Cd in plants are reviewed. This review also provides new insight that plants with enhanced Ca level have improved resistance to Cd stress.

  8. Active vitamin D deficiency mediated by extracellular calcium and phosphorus results in male infertility in young mice.

    Science.gov (United States)

    Sun, Weiwei; Chen, Lulu; Zhang, Wei; Wang, Rong; Goltzman, David; Miao, Dengshun

    2015-01-01

    We used mice with targeted deletion of 25-hydroxyvitamin D-1 α-hydroxylase [1α(OH)ase(-/-)] to investigate whether 1,25(OH)2D3 deficiency results in male infertility mediated by 1,25(OH)2D3 or extracellular calcium and phosphorus. Male 1α(OH)ase(-/-) and their wild-type littermates fed either a normal diet or a rescue diet from weaning were mated at 6-14 wk of age with female wild-type mice on the same diet. The fertility efficiency of females was analyzed, and the reproductive phenotypes of males were evaluated by histopathological and molecular techniques. Hypocalcemic and hypophosphatemic male 1α(OH)ase(-/-) mice on a normal diet developed infertility characterized by hypergonadotropic hypogonadism, with downregulation of testicular calcium channels, lower intracellular calcium levels, decreased sperm count and motility, and histological abnormalities of the testes. The proliferation of spermatogenic cells was decreased with downregulation of cyclin E and CDK2 and upregulation of p53 and p21 expression, whereas apoptosis of spermatogenic cells was increased with upregulation of Bax and p-caspase 3 expression and downregulation of Bcl-xl expression. When serum calcium and phosphorus were normalized by the rescue diet, the defective reproductive phenotype in the male 1α(OH)ase(-/-) mice, including the hypergonadotropic hypogonadism, decreased sperm count and motility, histological abnormalities of testis, and defective spermatogenesis, was reversed. These results indicate that the infertility seen in male 1,25(OH)2D3-deficient mice is not a direct effect of active vitamin D deficiency on the reproductive system but is an indirect effect mediated by extracellular calcium and phosphorus. Copyright © 2015 the American Physiological Society.

  9. Brain intra- and extracellular sodium concentration in multiple sclerosis: a 7 T MRI study.

    Science.gov (United States)

    Petracca, Maria; Vancea, Roxana O; Fleysher, Lazar; Jonkman, Laura E; Oesingmann, Niels; Inglese, Matilde

    2016-03-01

    Intra-axonal accumulation of sodium ions is one of the key mechanisms of delayed neuro-axonal degeneration that contributes to disability accrual in multiple sclerosis. In vivo sodium magnetic resonance imaging studies have demonstrated an increase of brain total sodium concentration in patients with multiple sclerosis, especially in patients with greater disability. However, total sodium concentration is a weighted average of intra- and extra-cellular sodium concentration whose changes reflect different tissue pathophysiological processes. The in vivo, non-invasive measurement of intracellular sodium concentration is quite challenging and the few applications in patients with neurological diseases are limited to case reports and qualitative assessments. In the present study we provide first evidence of the feasibility of triple quantum filtered (23)Na magnetic resonance imaging at 7 T, and provide in vivo quantification of global and regional brain intra- and extra-cellular sodium concentration in 19 relapsing-remitting multiple sclerosis patients and 17 heathy controls. Global grey matter and white matter total sodium concentration (respectively P brain regional level, clusters of increased total sodium concentration and intracellular sodium concentration and decreased intracellular sodium volume fraction were found in several cortical, subcortical and white matter regions when patients were compared with healthy controls (P < 0.05 family-wise error corrected for total sodium concentration, P < 0.05 uncorrected for multiple comparisons for intracellular sodium concentration and intracellular sodium volume fraction). Measures of total sodium concentration and intracellular sodium volume fraction, but not measures of intracellular sodium concentration were correlated with T2-weighted and T1-weighted lesion volumes (0.05 < P < 0.01) and with Expanded Disability Status Scale (P < 0.05). Thus, suggesting that while intracellular sodium volume fraction decrease could

  10. Comparative expression of the extracellular calcium-sensing receptor in the mouse, rat, and human kidney.

    Science.gov (United States)

    Graca, J A Z; Schepelmann, M; Brennan, S C; Reens, J; Chang, W; Yan, P; Toka, H; Riccardi, D; Price, S A

    2016-03-15

    The calcium-sensing receptor (CaSR) was cloned over 20 years ago and functionally demonstrated to regulate circulating levels of parathyroid hormone by maintaining physiological serum ionized calcium concentration ([Ca(2+)]). The receptor is highly expressed in the kidney; however, intrarenal and intraspecies distribution remains controversial. Recently, additional functions of the CaSR receptor in the kidney have emerged, including parathyroid hormone-independent effects. It is therefore critical to establish unequivocally the localization of the CaSR in the kidney to relate this to its proposed physiological roles. In this study, we determined CaSR expression in mouse, rat, and human kidneys using in situ hybridization, immunohistochemistry (using 8 different commercially available and custom-made antibodies), and proximity ligation assays. Negative results in mice with kidney-specific CaSR ablation confirmed the specificity of the immunohistochemistry signal. Both in situ hybridization and immunohistochemistry showed CaSR expression in the thick ascending limb, distal tubule, and collecting duct of all species, with the thick ascending limb showing the highest levels. Within the collecting ducts, there was significant heterogeneity of expression between cell types. In the proximal tubule, lower levels of immunoreactivity were detected by immunohistochemistry and proximity ligation assays. Proximity ligation assays were the only technique to demonstrate expression within glomeruli. This study demonstrated CaSR expression throughout the kidney with minimal discrepancy between species but with significant variation in the levels of expression between cell and tubule types. These findings clarify the intrarenal distribution of the CaSR and enable elucidation of the full physiological roles of the receptor within this organ.

  11. Changes in extracellular calcium activity during gravity sensing in maize roots

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerkman, T.; Cleland, R.E. (Univ. of Washington, Seattle (USA))

    1990-05-01

    A redistribution of calcium downward across the root cap has been proposed as an essential part of gravitropism in roots. Exogenous {sup 45}Ca moves preferentially downward across gravistimulated maize root tips. However, because of the many calcium-binding sites in the apoplast, this might not result in a physiologically effect change in the apoplasmic calcium activity. To test whether there is such a change, we measured the effect of gravistimulation on the calcium activity with calcium-specific microelectrodes. Decapped maize roots (Zea mays L. cv. Golden Cross Bantam) were grown for 31 h to regenerate gravitropic sensitivity, but not root caps. The calcium activity in the apoplasm surrounding the gravity-sensing cells could then be measured. The initial pCa was 2.60 {plus minus} 0.28 (approx 2.5 mM). The calcium activity on the upper side of the root tip remained constant for about five minutes after gravistimulation, then decreased by about one half. On the lower side, after a similar lag the calcium activity doubled. Control roots, which were decapped but measured before recovering gravisensitivity (19 h), showed no change in calcium activity. We have found a distinct and rapid differential in the apoplasmic calcium activity between the upper and lower sides of gravistimulated maize root tips.

  12. Does extracellular calcium determine what pool of GABA is the target for alpha-latrotoxin?

    Science.gov (United States)

    Storchak, L G; Linetska, M V; Himmelreich, N H

    2002-04-01

    Presynaptic neurotoxin alpha-latrotoxin, from the venom of Latrodectus mactans tredecimguttatus, causes massive [(3)H]GABA release from rat brain synaptosomes, irrespective of calcium presence in the extracellular medium. Whether the binding of alpha-latrotoxin to Ca(2+)-dependent (neurexin 1 alpha) or to Ca(2+)-independent (latrophilin) receptor triggers [(3)H]GABA release by the same mechanisms or different ones, inducing either exocytotic process or outflow by mobile membrane GABA transporter, is unknown. We examined alpha-latrotoxin-evoked [(3)H]GABA release from synaptosomes which cytosolic [(3)H]GABA pool was depleted either by applying competitive inhibitors of the GABA transporter, nipecotic acid and 2,4-diaminobutyric acid, or by permeation with digitonin. We also compared the effect of the GABA transporter inhibitors on depolarisation-evoked and alpha-latrotoxin-evoked [(3)H]GABA release using as depolarising agents 4-aminopyridine and high KCl in the Ca(2+)-containing and in Ca(2+)-free medium, respectively. Incubation of synaptosomes with nipecotic acid induced the essential acceleration of unstimulated [(3)H]GABA release and deep inhibition of high KCl-evoked Ca(2+)-independent [(3)H]GABA release. In contrast, at the similar conditions the effect of alpha-latrotoxin was greatly augmented with respect to the control response. Another way to assay what GABA pool was involved in alpha-latrotoxin-induced release lays in an analysis of the effects of depolarisation and alpha-latrotoxin in consecutive order. The preliminary 4-aminopyridine-stimulated [(3)H]GABA release attenuated the toxin effect. But when depolarisation occurred in Ca(2+)-free medium, no influence on alpha-latrotoxin effect was revealed. Employing digitonin-permeated synaptosomes, we have shown that alpha-latrotoxin could stimulate [3H]GABA release in the medium with 1mM EGTA, this effect of the toxin was blocked by concanavalin A and was ATP-dependent. The latter suggests that alpha

  13. The effect of morphine sensitization on extracellular concentrations of GABA in dorsal hippocampus of male rats.

    Science.gov (United States)

    Farahmandfar, Maryam; Zarrindast, Mohammad-Reza; Kadivar, Mehdi; Karimian, Seyed Morteza; Naghdi, Nasser

    2011-11-01

    Repeated, intermittent exposure to drugs of abuse, such as morphine results in response enhancements to subsequent drug treatments, a phenomenon referred to as behavioral sensitization. As persistent neuronal sensitization may contribute to the long-lasting consequences of drug abuse, characterizing the neurochemical mechanisms of sensitization is providing insights into addiction. Although it has been shown that GABAergic systems in the CA1 region of dorsal hippocampus are involved in morphine sensitization, the alteration of extracellular level of GABA in this area in morphine sensitization has not been investigated. In the present study, using the in vivo microdialysis technique, we investigated the effect of morphine sensitization on extracellular GABA concentration in CA1 region of dorsal hippocampus of freely moving rats. Sensitization was induced by subcutaneous (s.c.) injection of morphine, once daily for 3 days followed by 5 days free of the opioid treatment. The results showed that extracellular GABA concentration in CA1 was decreased following acute administration of morphine in non-sensitized rats. However, morphine-induced behavioral sensitization significantly increased the extracellular GABA concentration in this area. The enhancement of GABA in morphine sensitized rats was inhibited by administration of naloxone 30 min before each of three daily doses of morphine. These results suggest an adaptation of the GABAergic neuronal transmission in dorsal hippocampus induced by morphine sensitization and it is implied that opioid receptors may play an important role in this effect.

  14. Effects of dietary clinoptilolite and calcium levels on uric acid and calcium blood concentrations and bone quality of commercial layers

    Directory of Open Access Journals (Sweden)

    DA Berto

    2013-06-01

    Full Text Available The objective of the present study was to evaluate the effect of clinoptilolite and calcium levels on uric acid and calcium blood profile and bone quality of commercial layers. A total of 576 birds were distributed according to a completely randomized experimental design in a 3x4 factorial arrangement (calcium levels of 2.5, 3.1, or 3.7% and clinoptilolite levels of 0.0, 0.15, 0.25, or 0.50%, into 12 treatments with six replicates of eight birds per cage (experimental unit. The experimental period was 112 days. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. Blood uric acid was significantly influenced by the interaction of the evaluated factors. Clinoptilolite levels significantly increased blood calcium levels. There was no effect of dietary calcium levels on any of the evaluated characteristics. It was concluded that feeding layers with up to 0.50% clinoptilolite does not benefit blood uric acid and calcium concentrations and does not affect their bone quality. When layers at the end of the first laying cycle are fed ad libitum and present 119.50g/hen/day average feed intake, 3.1% dietary calcium promotes 3.7g/hen/day calcium intake, which is sufficient to maintain adequate calcium blood levels and bone quality.

  15. Extracellular ATP inhibits root gravitropism at concentrations that inhibit polar auxin transport

    Science.gov (United States)

    Tang, Wenqiang; Brady, Shari R.; Sun, Yu; Muday, Gloria K.; Roux, Stanley J.

    2003-01-01

    Raising the level of extracellular ATP to mM concentrations similar to those found inside cells can block gravitropism of Arabidopsis roots. When plants are grown in Murashige and Skoog medium supplied with 1 mM ATP, their roots grow horizontally instead of growing straight down. Medium with 2 mM ATP induces root curling, and 3 mM ATP stimulates lateral root growth. When plants are transferred to medium containing exogenous ATP, the gravity response is reduced or in some cases completely blocked by ATP. Equivalent concentrations of ADP or inorganic phosphate have slight but usually statistically insignificant effects, suggesting the specificity of ATP in these responses. The ATP effects may be attributable to the disturbance of auxin distribution in roots by exogenously applied ATP, because extracellular ATP can alter the pattern of auxin-induced gene expression in DR5-beta-glucuronidase transgenic plants and increase the response sensitivity of plant roots to exogenously added auxin. The presence of extracellular ATP also decreases basipetal auxin transport in a dose-dependent fashion in both maize (Zea mays) and Arabidopsis roots and increases the retention of [(3)H]indole-3-acetic acid in root tips of maize. Taken together, these results suggest that the inhibitory effects of extracellular ATP on auxin distribution may happen at the level of auxin export. The potential role of the trans-plasma membrane ATP gradient in auxin export and plant root gravitropism is discussed.

  16. Release of ATP from marginal cells in the cochlea of neonatal rats can be induced by changes in extracellular and intracellular ion concentrations.

    Directory of Open Access Journals (Sweden)

    Yating Peng

    Full Text Available BACKGROUND: Adenosine triphosphate (ATP plays an important role in the cochlea. However, the source of ATP and the mechanism by which it is released remain unclear. This study investigates the presence and release mechanism of ATP in vitro cultured marginal cells isolated from the stria vascularis of the cochlea in neonatal rats. METHODS: Sprague-Dawley rats aged 1-3 days old were used for isolation, in vitro culture, and purification of marginal cells. Cultured marginal cells were verified by flow cytometry. Vesicles containing ATP in these cells were identified by fluorescence staining. The bioluminescence assay was used for determination of ATP concentration in the extracellular fluid released by marginal cells. Assays for ATP concentration were performed when the ATP metabolism of cells was influenced, and ionic concentrations in intracellular and extracellular fluid were found to change. RESULTS: Evaluation of cultured marginal cells with flow cytometry revealed the percentage of fluorescently-labeled cells as 92.9% and 81.9%, for cytokeratin and vimentin, respectively. Quinacrine staining under fluorescence microscopy revealed numerous green, star-like spots in the cytoplasm of these cells. The release of ATP from marginal cells was influenced by changes in the concentration of intracellular and extracellular ions, namely extracellular K(+ and intra- and extracellular Ca(2+. Furthermore, changes in the concentration of intracellular Ca(2+ induced by the inhibition of the phospholipase signaling pathway also influence the release of ATP from marginal cells. CONCLUSION: We confirmed the presence and release of ATP from marginal cells of the stria vascularis. This is the first study to demonstrate that the release of ATP from such cells is associated with the state of the calcium pump, K(+ channel, and activity of enzymes related to the phosphoinositide signaling pathway, such as adenylate cyclase, phospholipase C, and phospholipase A(2.

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

    Directory of Open Access Journals (Sweden)

    Abarbanel Henry DI

    2007-02-01

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

  18. 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...... 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...

  19. What determines the calcium concentration of speleothem-forming drip waters?

    Science.gov (United States)

    Baker, Andy; Flemons, Ingrid; Andersen, Martin S.; Coleborn, Katie; Treble, Pauline C.

    2016-08-01

    Cave drip water calcium ion concentration is a primary determinant of speleothem deposition and growth rate. The factors that determine drip water calcium ion concentrations are the soil and vadose zone CO2 concentrations, and the hydrogeochemical evolution of the water from soil to cave. Here, we use a systematic literature review of cave drip water calcium concentrations, combined with PHREEQC equilibrium modelling, to investigate the global relationship between calcium concentration and surface climate. Our results are discussed in the context of understanding the climatic and environmental controls on drip water calcium concentration, speleothem growth rates and proxies of past climate and environmental change. We use an empirical, global soil CO2 concentration-temperature relationship to derive PHREEQC modelled cave drip water calcium concentrations. The global mean modelled drip water calcium concentration is close to that observed, but it over-predicts at high and low temperatures, and significantly under-predicts at temperate conditions. We hypothesise that closed system hydrochemical evolution due to water saturation is an important control on carbonate dissolution at colder temperatures. Under warmer conditions, for example temperate climates with a dry and hot or warm summer, seasonally-limited water availability can lead to: microbial and root respiration; wildfire; and prior calcite precipitation, all of which limit drip water calcium concentrations. In temperate climates with no dry season, higher CO2 concentrations than modelled from soil values are necessary to explain the observed drip water calcium values, which we propose is from an additional source of CO2 from microbial activity and root respiration in the vadose zone during open system hydrochemical evolution.

  20. Enhanced Proliferation of Porcine Bone Marrow Mesenchymal Stem Cells Induced by Extracellular Calcium is Associated with the Activation of the Calcium-Sensing Receptor and ERK Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jingjing Ye

    2016-01-01

    Full Text Available Porcine bone marrow mesenchymal stem cells (pBMSCs have the potential for application in regenerative medicine. This study aims to investigate the effects of extracellular calcium (Ca2+o on pBMSCs proliferation and to explore the possible underlying mechanisms. The results demonstrated that 4 mM Ca2+o significantly promoted pBMSCs proliferation by reducing the G0/G1 phase cell percentage and by increasing the S phase cell proportion and the proliferation index of pBMSCs. Accordingly, Ca2+o stimulated the expression levels of proliferative genes such as cyclin A2, cyclin D1/3, cyclin E2, and PCNA and inhibited the expression of p21. In addition, Ca2+o resulted in a significant elevation of intracellular calcium and an increased ratio of p-ERK/ERK. However, inhibition of calcium-sensing receptor (CaSR by its antagonist NPS2143 abolished the aforementioned effects of Ca2+o. Moreover, Ca2+o-induced promotion of pBMSCs proliferation, the changes of proliferative genes expression levels, and the activation of ERK1/2 signaling pathway were effectively blocked by U0126, a selective ERK kinase inhibitor. In conclusion, our findings provided evidence that the enhanced pBMSCs proliferation in response to Ca2+o was associated with the activation of CaSR and ERK1/2 signaling pathway, which may be useful for the application of pBMSCs in future clinical studies aimed at tissue regeneration and repair.

  1. Insulinotropic actions of Moringa oleifera involves the induction of membrane depolarization and enhancement of intracellular calcium concentration

    Directory of Open Access Journals (Sweden)

    Opeolu O. Ojo

    2015-03-01

    Methods: Phytochemical composition of M.oleifera extract was determined using standard procedures. Total flavonoid and total phenolic compounds in the extract were also quantified. Effects of the extracts on glucose stimulated insulin secretion, membrane depolarization and intracellular calcium concentration were investigated using BRIN-BD11 clonal pancreatic beta cells. Results: Results obtained showed the preponderance of alkaloids, flavonoids, glycosides, phenols, saponins and tannins in the extract. The glucose dependent insulinotropic effects of the extract were significantly inhibited in the presence of diazoxide (48% or verapamil (35% and in the absence of extracellular calcium (47%. Co-incubation of cells with the extract and IBMX (3-isobutyl-1-methylxanthine or tolbutamide increased insulin secretion by 2-fold while a 1.2-fold increase was observed in cells depolarized with 30 mM KCl in the presence of the plant extract. The extract significantly induced membrane depolarization (7.1-fold and enhanced intracellular calcium concentration (2.6-fold in BRIN-BD11 cells. Conclusion: These observations suggest that the insulinotropic actions of acetone extract of M.oleifera may be mediated via the KATP-dependent pathway of insulin release. [J Exp Integr Med 2015; 5(1.000: 36-41

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

    National Research Council Canada - National Science Library

    Borst, Alexander; Abarbanel, Henry D I

    2007-01-01

    .... By investigating the underlying reaction kinetics, we show that in some ranges of kinetic parameters one can explicitly link the time dependent indicator signal to the time-course of the calcium...

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

    OpenAIRE

    Abarbanel Henry DI; Borst Alexander

    2007-01-01

    Abstract Background Optical indicators of cytosolic calcium levels have become important experimental tools in systems and cellular neuroscience. Indicators are known to interfere with intracellular calcium levels by acting as additional buffers, and this may strongly alter the time-course of various dynamical variables to be measured. Results By investigating the underlying reaction kinetics, we show that in some ranges of kinetic parameters one can explicitly link the time dependent indicat...

  4. Effects of calcium ion concentration on starch hydrolysis of barley α-amylase isozymes

    DEFF Research Database (Denmark)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee

    2008-01-01

    in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However...

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

    Science.gov (United States)

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

    2016-08-01

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

  6. Plasma cytokine concentration changes induced by the antitumor agents dipterinyl calcium pentahydrate (DCP) and related calcium pterins.

    Science.gov (United States)

    Moheno, Phillip; Pfleiderer, Wolfgang; Fuchs, Dietmar

    2009-01-01

    Analysis of plasma cytokine concentration changes determined that oral dosing with the antitumor agent (1:4 mol:mol) calcium pterin (CaPterin) increased plasma IL-10, decreased plasma IL-6, and decreased plasma IFN-gamma concentrations in nude mice with MDA-MB-231 xenograph tumors [Moheno, P., Pfleiderer, W., Dipasquale, A.G., Rheingold, A.L., Fuchs, D., 2008. Cytokine and IDO metabolite changes effected by calcium pterin during inhibition of MDA-MB-231 xenograph tumors in nude mice. Int. J. Pharm. 355, 238-248]. A further analysis, reported here, of plasma cytokine concentration changes in nude mice with the same tumor xenographs treated with dipterinyl calcium pentahydrate (DCP), (1:2 mol:mol) calcium pterin, and CaCl(2).2H(2)O has been carried out. The measured cytokines included: IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, IFN-gamma, and TNF-alpha. The major preliminary findings from the analyses of these data are that (1) the overall relative tumor volumes for the treatments correlated significantly with a full study antitumor plasma cytokine pattern (fsAPCP), a composite measure consisting of decreased plasma IL-6 and increased IL-4 concentrations, and (2) DCP induces a significant threshold antitumor response strongly correlated to a derived DCP antitumor plasma cytokine pattern (DCP/APCP) consisting of plasma IL-12, IL-6, and IL-4 concentration changes. This DCP/APCP composite measure identifies plasma IL-12 concentration increases, plasma IL-6 concentration decreases, and plasma IL-4 concentration increases correlated to relative tumor volume decreases caused by DCP dosing. The finding that the novel calcium pterins and CaCl(2).2H(2)O treatments decrease plasma IL-6 concentrations corroborates the previous finding that CaPterin dosing decreases plasma IL-6 concentrations in this mouse/tumor system [Moheno, P., Pfleiderer, W., Dipasquale, A.G., Rheingold, A.L., Fuchs, D., 2008. Cytokine and IDO metabolite changes effected by calcium pterin during inhibition

  7. A standardized method to determine the concentration of extracellular vesicles using tunable resistive pulse sensing

    Directory of Open Access Journals (Sweden)

    Robert Vogel

    2016-09-01

    Full Text Available Background: Understanding the pathogenic role of extracellular vesicles (EVs in disease and their potential diagnostic and therapeutic utility is extremely reliant on in-depth quantification, measurement and identification of EV sub-populations. Quantification of EVs has presented several challenges, predominantly due to the small size of vesicles such as exosomes and the availability of various technologies to measure nanosized particles, each technology having its own limitations. Materials and Methods: A standardized methodology to measure the concentration of extracellular vesicles (EVs has been developed and tested. The method is based on measuring the EV concentration as a function of a defined size range. Blood plasma EVs are isolated and purified using size exclusion columns (qEV and consecutively measured with tunable resistive pulse sensing (TRPS. Six independent research groups measured liposome and EV samples with the aim to evaluate the developed methodology. Each group measured identical samples using up to 5 nanopores with 3 repeat measurements per pore. Descriptive statistics and unsupervised multivariate data analysis with principal component analysis (PCA were used to evaluate reproducibility across the groups and to explore and visualise possible patterns and outliers in EV and liposome data sets. Results: PCA revealed good reproducibility within and between laboratories, with few minor outlying samples. Measured mean liposome (not filtered with qEV and EV (filtered with qEV concentrations had coefficients of variance of 23.9% and 52.5%, respectively. The increased variance of the EV concentration measurements could be attributed to the use of qEVs and the polydisperse nature of EVs. Conclusion: The results of this study demonstrate the feasibility of this standardized methodology to facilitate comparable and reproducible EV concentration measurements.

  8. The serum concentration of the calcium binding protein S100B is positively associated with cognitive performance in older adults

    Directory of Open Access Journals (Sweden)

    Virginie eLam

    2013-09-01

    Full Text Available S100B is a calcium-binding peptide produced predominantly by astroglial cells in the central nervous system. S100B paradoxically has neurotrophic and apoptotic effects, dependent on extracellular concentration. This study investigated the relationship between serum S100B levels and neuropsychological performance across a range of cognitive domains in healthy older aged adults. A cohort of 219 participants between the ages of 43 and 84 years (141 female were recruited. Subjects provided a fasting blood sample for S100B measurement (Mean = 0.24 ng/mL, SD = 0.14 and completed a battery of neuropsychological tests. S100B concentrations (both with and without the covariates of age and sex were positively associated with the following measures of cognitive performance: digit symbol coding, Stroop test and measures of verbal ability. The results from this study show that serum S100B is positively associated with better cognitive performance in healthy older adults.

  9. Calcium supplementation increases blood creatinine concentration in a randomized controlled trial.

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    Elizabeth L Barry

    Full Text Available BACKGROUND: Calcium supplements are widely used among older adults for osteoporosis prevention and treatment. However, their effect on creatinine levels and kidney function has not been well studied. METHODS: We investigated the effect of calcium supplementation on blood creatinine concentration in a randomized controlled trial of colorectal adenoma chemoprevention conducted between 2004-2013 at 11 clinical centers in the United States. Healthy participants (N = 1,675 aged 45-75 with a history of colorectal adenoma were assigned to daily supplementation with calcium (1200 mg, as carbonate, vitamin D3 (1000 IU, both, or placebo for three or five years. Changes in blood creatinine and total calcium concentration were measured after one year of treatment and multiple linear regression was used to estimate effects on creatinine concentrations. RESULTS: After one year of treatment, blood creatinine was 0.013±0.006 mg/dL higher on average among participants randomized to calcium compared to placebo after adjustment for other determinants of creatinine (P = 0.03. However, the effect of calcium treatment appeared to be larger among participants who consumed the most alcohol (2-6 drinks/day or whose estimated glomerular filtration rate (eGFR was less than 60 ml/min/1.73 m2 at baseline. The effect of calcium treatment on creatinine was only partially mediated by a concomitant increase in blood total calcium concentration and was independent of randomized vitamin D treatment. There did not appear to be further increases in creatinine after the first year of calcium treatment. CONCLUSIONS: Among healthy adults participating in a randomized clinical trial, daily supplementation with 1200 mg of elemental calcium caused a small increase in blood creatinine. If confirmed, this finding may have implications for clinical and public health recommendations for calcium supplementation. TRIAL REGISTRATION: ClinicalTrials.gov NCT00153816.

  10. Relationship between Salivary Alkaline Phosphatase Enzyme Activity and The Concentrations of Salivary Calcium and Phosphate Ions

    Directory of Open Access Journals (Sweden)

    Mina Jazaeri

    2015-04-01

    Full Text Available Although salivary alkaline phosphatase (ALP can balance de- and remineralization processes of enamel, there is no evidence regarding its effects on the concentrations of calcium and phosphate in saliva. The present study aims to determine the relationship between salivary ALP activity and the concentrations of calcium and phosphate in saliva. In this cross-sectional study, we evaluated salivary markers in 120 males, ages 19 to 44 years. All participants provided 5 mL of unstimulated whole saliva and the level of enzyme activity as well as calcium and phosphate concentrations were measured using a colorimetric method. Data were gathered and analyzed by statistical package for social sciences (SPSS 13.00 using Pearson correlation test. A p value of 0.05. According to the results of the present study, there was no significant relation between salivary ALP activity and calcium and phosphate concentrations in saliva. However, further research is highly recommended.

  11. Reduction of calcium flux from the extracellular region and endoplasmic reticulum by amorphous nano-silica particles owing to carboxy group addition on their surface

    Directory of Open Access Journals (Sweden)

    Akira Onodera

    2017-03-01

    Full Text Available Several studies have reported that amorphous nano-silica particles (nano-SPs modulate calcium flux, although the mechanism remains incompletely understood. We thus analyzed the relationship between calcium flux and particle surface properties and determined the calcium flux route. Treatment of Balb/c 3T3 fibroblasts with nano-SPs with a diameter of 70 nm (nSP70 increased cytosolic calcium concentration, but that with SPs with a diameter of 300 or 1000 nm did not. Surface modification of nSP70 with a carboxy group also did not modulate calcium flux. Pretreatment with a general calcium entry blocker almost completely suppressed calcium flux by nSP70. Preconditioning by emptying the endoplasmic reticulum (ER calcium stores slightly suppressed calcium flux by nSP70. These results indicate that nSP70 mainly modulates calcium flux across plasma membrane calcium channels, with subsequent activation of the ER calcium pump, and that the potential of calcium flux by nano-SPs is determined by the particle surface charge.

  12. Mechanisms of astrocytic K(+) clearance and swelling under high extracellular K(+) concentrations.

    Science.gov (United States)

    Murakami, Shingo; Kurachi, Yoshihisa

    2016-03-01

    In response to the elevation of extracellular K(+) concentration ([K(+)]out), astrocytes clear excessive K(+) to maintain conditions necessary for neural activity. K(+) clearance in astrocytes occurs via two processes: K(+) uptake and K(+) spatial buffering. High [K(+)]out also induces swelling in astrocytes, leading to edema and cell death in the brain. Despite the importance of astrocytic K(+) clearance and swelling, the underlying mechanisms remain unclear. Here, we report results from a simulation analysis of astrocytic K(+) clearance and swelling. Astrocyte models were constructed by incorporating various mechanisms such as intra/extracellular ion concentrations of Na(+), K(+), and Cl(-), cell volume, and models of Na,K-ATPase, Na-K-Cl cotransporter (NKCC), K-Cl cotransporter, inwardly-rectifying K(+) (KIR) channel, passive Cl(-) current, and aquaporin channel. The simulated response of astrocyte models under the uniform distribution of high [K(+)]out revealed significant contributions of NKCC and Na,K-ATPase to increases of intracellular K(+) and Cl(-) concentrations, and swelling. Moreover, we found that, under the non-uniform distribution of high [K(+)]out, KIR channels localized at synaptic clefts absorbed excess K(+) by depolarizing the equivalent potential of K(+) (E K) above membrane potential, while K(+) released through perivascular KIR channels was enhanced by hyperpolarizing E K and depolarizing membrane potential. Further analysis of simulated drug effects revealed that astrocyte swelling was modulated by blocking each of the ion channels and transporters. Our simulation analysis revealed controversial mechanisms of astrocytic K(+) clearance and swelling resulting from complex interactions among ion channels and transporters.

  13. Mechanism of action of extracellular calcium on isoprenaline-evoked amylase secretion from isolated rat parotid glands.

    Science.gov (United States)

    Argent, B E; Arkle, S

    1985-12-01

    The effects of extracellular Ca2+ deprivation on amylase secretion, 45Ca efflux and cyclic adenosine 3',5'-monophosphate (cyclic AMP) metabolism were investigated in incubated parotid glands of young rats. Reducing the extracellular Ca2+ concentration from 2.5 X 10(-3) M to 10(-6) M had no effect on amylase secretion but did increase the rate of 45Ca efflux from unstimulated glands. Isoprenaline (10(-5) M) increased amylase secretion and the rate of 45Ca efflux in media containing 2.5 X 10(-3) M-Ca2+, and also increased the parotid cyclic AMP content. When glands were pre-incubated for either 10, 20, or 30 min in media containing either 10(-3) or 10(-6) M-Ca2+ there was no effect on the peak rate of amylase secretion stimulated by isoprenaline but the response took longer to develop. The effects of the same experimental manoeuvre on the net change in 45Ca efflux stimulated by isoprenaline were consistent with the idea that the beta-adrenergic agonist mobilizes Ca2+ from a number of intracellular pools. When glands were pre-incubated for 100 min in Ca2+-depleted buffers and then exposed to isoprenaline a triphasic effect on amylase secretion was observed. The secretory response was depressed when the extracellular Ca2+ concentration was lowered from 2.5 X 10(-3) M to 10(-3) M; remained unaffected when the extracellular Ca2+ was further reduced to 10(-5) M; and was virtually abolished when the extracellular Ca2+ concentration was decreased to 10(-6) M. When glands were pre-incubated for 100 min in media containing Ca2+ at concentrations above 10(-5) M and then stimulated with isoprenaline parallel changes in cyclic AMP content and amylase secretion were observed. At lower Ca2+ concentrations there was no further reduction in cyclic AMP content. The lipophilic cyclic AMP analogue N6,O2-dibutyryl adenosine 3',5'-monophosphate (dibutyryl cyclic AMP) mimicked the effects of isoprenaline on amylase secretion and 45Ca efflux. However, the amylase secretory response took

  14. EFFECT OF ELECTROACUPUNCTURE AND CALCIUM-CHANNEL INHIBITORS ON CYTOPLASMIC FREE CALCIUM CONCENTRATION OF MOUSE BRAIN CELLS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-mei; XIE Ji-min; CHEN Min; ZHANG Yan

    2005-01-01

    Objective: To study the effect of electroacupuncture (EA) and Verapamil and Nifedipine (calcium channel inhibitors) on free calcium concentrations of cells and intrasynaptosomes in hypothalamus (HT), periaqueductual grey matter (PAG) and hippocampus (HIP) of mice. Methods: The female ICR mice were randomly divided into control, EA, CaCl2 and CaCl2+EA groups (n=8 in each group). Pain threshold was detected by using radiation-heat irradiation-induced tail flick method. EA (8 Hz, a suitable stimulating strength, dense-sparse waves and duration of 30 min) was applied to"Shuigou" (水沟 GV 26) and "Chengjiang" (承浆CV 24). CaCl2 (10 μL, 0.2 μmol/L) was injected into the lateral cerebral ventricle of mice after EA. The concentrations of cytosolic free calcium ([Ca2+]i) in HIP, PAG, HT cell suspension specimen and hippocampal intrasynaptosome suspension of mice were determined by the fluorescent calcium indicator Fura-2-AM and a spectrofluorometer. Results: During EA analgesia, the intracellular free [Ca2+]i in HT and PAG specimens and intrsynaptosomal [Ca2+]i of the 3 cerebral regions decreased considerably (P<0.05~0.01), but that in hippocampal cell suspension increased significantly (P<0.01) in comparison with control group. The concentrations of hippocampal intrasynaptosomal free [Ca2+]i decreased significantly after adding Verapamil and Nifedipine to the extracted hippocampal intrasynaptosomal specimen. Microinjection of CaCl2 into lateral ventricle had no apparent influence on degree of analgesia (DA)% and intracellular and intrasynapsotomal [Ca2+]i, but significantly lower DA% and reduce changes of cytosolic and intrasynaptosomal [Ca2+]i induced by EA stimulation. Conclusion: Calcium ion in the neurons and intrasynaptosome of HT, PAG and HIP is involved in electroacupuncture analgesia.

  15. Basic mechanism leading to stimulation of glycogenolysis by isoproterenol, EGF, elevated extracellular K+ concentrations, or GABA.

    Science.gov (United States)

    Xu, Junnan; Song, Dan; Bai, Qiufang; Cai, Liping; Hertz, Leif; Peng, Liang

    2014-04-01

    Glycogenolysis, in brain parenchyma an astrocyte-specific process, has changed from being envisaged as an emergency procedure to playing central roles during brain response to whisker stimulation, memory formation, astrocytic K(+) uptake and stimulated release of ATP. It is activated by several transmitters and by even very small increases in extracellular K(+) concentration, and to be critically dependent upon an increase in free cytosolic Ca(2+) concentration ([Ca(2+)]i), whereas cAMP plays only a facilitatory role together with increased [Ca(2+)]i. Detailed knowledge about the signaling pathways eliciting glycogenolysis is therefore of interest and was investigated in the present study in well differentiated cultures of mouse astrocytes. The β-adrenergic agonist isoproterenol stimulated glycogenolysis by a β1-adrenergic effect, which initiated a pathway in which cAMP/protein kinase A activated a Gi/Gs shift, leading to Ca(2+)-activated glycogenolysis. Inhibition of this pathway downstream of cAMP but upstream of the Gi/Gs shift abolished the glycogenolysis. However, inhibitors operating downstream of the Ca(2+)-sensitive step, but preventing transactivation-mediated epidermal growth factor (EGF) receptor stimulation, a later step in the activated pathway, also caused inhibition of glycogenolysis. For this reason the effect of EGF was investigated and it was found to be glycogenolytic. Large increases in extracellular K(+) activated glycogenolysis by a nifedipine-inhibited L-channel opening allowing influx of Ca(2+), known to be glycogenolysis-dependent. Small increases (addition of 5 mM KCl) caused a smaller effect by a similarly glycogenolysis-reliant opening of an IP3 receptor-dependent ouabain signaling pathway. The same pathway could be activated by GABA (also in brain slices) due to its depolarizing effect in astrocytes.

  16. Ultrastructural characteristics of fibrin clots from canine and feline platelet concentrates activated with calcium gluconate or calcium gluconate plus batroxobin

    OpenAIRE

    Silva, Raúl F; Carmona, Jorge U; Rezende, Cleuza MF

    2013-01-01

    Background The aim of this study was to use transmission electron microscopy to describe the ultrastructural characteristics of clots obtained from canine and feline platelet concentrates (PC) that had been activated with calcium gluconate (CG) or CG plus batroxobin (CGB). Platelets from fibrin clots were classified according their morphological changes. The area of the intercellular space (μm2), the area of the fibrin fibers (μm2), and the width of the fibrin fibers (μm) were determined for ...

  17. Loss on drying, calcium concentration and pH of fluoride dentifrices

    Science.gov (United States)

    Brito, Arella Cristina Muniz; Dantas, Lívia Rocha; De Brito, André Luiz Fiquene; Muniz, Ana Cristina Silva; Ramos, Ianny Alves; Cardoso, Andreia Medeiros Rodrigues; Xavier, Alidianne Fábia Cabral; Cavalcanti, Alessandro Leite

    2015-01-01

    Introduction: Fluoride dentifrices containing calcium carbonate have advantages such as control of dental plaque and progression of dental caries, also contributing to oral hygiene, represent most dentifrices marketed in Brazil. Aim: To evaluate the physicochemical properties of seven fluoride dentifrices containing calcium carbonate in relation to hydrogen potential (pH), loss on drying and calcium concentration. Materials and Methods: Data collection was performed using the potentiometric method for pH ranges, gravimetric analysis for loss on drying and atomic absorption spectrometry for the concentration of calcium ions. All tests were performed in triplicate and the analysis was performed entirely at random according to one-way analysis of variance at 5% significance level. Results: The pH values were alkaline and ranged from 8.67 (Oral-B 123®) to 10.03 (Colgate Máxima Proteção Anticáries®). The results of loss on drying ranged from 33.81% (Oral-B 123®) to 61.13% (Close Up®), with significant differences between brands tested. In relation to the calcium content, the highest and lowest concentrations were found in dentifrices Even® (155.55 g/kg) and Colgate Ultra Branco® (129 g/kg), respectively, with significant difference (P dentifrices analyzed showed alkaline pH and high levels of loss on drying and calcium concentration. However, these physicochemical characteristics differed according to the different brands tested. PMID:25821380

  18. Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2014-02-01

    Full Text Available Genetic improvement of common bean nutritional quality has advantages in marketing and can contribute to society as a food source. The objective of this study was to evaluate the genetic variability for grain yield, calcium and iron concentrations in grains of inbred common bean lines obtained by different breeding methods. For this, 136 F7 inbred lines were obtained using the Pedigree method and 136 F7 inbred lines were obtained using the Single-Seed Descent (SSD method. The lines showed genetic variability for grain yield, and concentrations of calcium and iron independently of the method of advancing segregating populations. The Pedigree method allows obtaining a greater number of lines with high grain yield. Selection using the SSD method allows the identification of a larger number of lines with high concentrations of calcium and iron in grains. Weak negative correlations were found between grain yield and calcium concentration (r = -0.0994 and grain yield and iron concentration (r = -0.3926. Several lines show genetic superiority for grain yield and concentrations of calcium and iron in grains and their selection can result in new common bean cultivars with high nutritional quality.

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

    Directory of Open Access Journals (Sweden)

    Seth H. Weinberg

    2012-01-01

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

  20. Orthokinetic flocculation of caseinate-stabilized emulsions : influence of calcium concentration, shear rate and protein content

    NARCIS (Netherlands)

    Schokker, E.P.; Dalgleish, D.G.

    2000-01-01

    Calcium-induced flocculation of caseinate-stabilized soybean oil-in- water emulsions in conditions of Couette flow was studied. A concentrated emulsion (20% oil, 0.5-2.0% sodium caseinate in 20 mM imidazole, pH 7) was diluted 20 times in buffer containing concentrations of CaCl2 between 9 and 17 mM

  1. Calcium

    Science.gov (United States)

    ... in luck if you like sardines and canned salmon with bones. Almond milk. previous continue Working Calcium ... drinks, and cereals. Other Considerations for Building Bones Vitamin D is essential for calcium absorption, so it's ...

  2. Using two dyes with the same fluorophore to monitor cellular calcium concentration in an extended range.

    Directory of Open Access Journals (Sweden)

    Lourdes Figueroa

    Full Text Available We extend the sensitivity of quantitative concentration imaging to an approximately 1000-fold range of concentrations by a method that uses two fluorescent dyes with the same fluorophore, having different affinity for the monitored species. While the formulation and illustration refer to a monitor of calcium concentration, the method is applicable to any species that binds to multiple indicators with the same spectral properties. The use of a common fluorophore has the virtue of leaving vast regions of the electromagnetic spectrum available for other applications. We provide the exact analytic expression relating measured fluorescence to [Ca(2+] at equilibrium and an approximate analytic expression that does not require the equilibrium assumption. The sensitivity of the method is calculated numerically for two useful dye pairs. As illustrative application of the enhanced measurement, we use fluo-4 and fluo-4FF to image the calcium wave produced by a cardiac myocyte in response to a small artificial calcium spark.

  3. Time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water

    Institute of Scientific and Technical Information of China (English)

    WU Jiang-lai; LU Yuan; Li Ying; CHENG Kai; GUO Jin-jia; ZHENG Rong-er

    2011-01-01

    @@ The laser induced breakdown spectroscopy (LIBS) is an element analysis technique with the advantages of real time detection, simultaneous multi-element identification, and in-situ and stand-off capacities.To evaluate its potential of ocean applications, in this paper, the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters, the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation, and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50ppm is achieved for calcium detection in CaC12 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS, and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.

  4. Calcium regulates motility and protein phosphorylation by changing cAMP and ATP concentrations in boar sperm in vitro.

    Science.gov (United States)

    Li, Xinhong; Wang, Lirui; Li, Yuhua; Zhao, Na; Zhen, Linqing; Fu, Jieli; Yang, Qiangzhen

    2016-09-01

    Considering the importance of calcium (Ca(2+)) in regulating sperm capacitation, hyperactivation and acrosome reaction, little is known about the molecular mechanism of action of this ion in this process. In the present study, assessment of the molecular mechanism from the perspective of energy metabolism occurred. Sperm motility variables were determined using computer-assisted sperm analysis (CASA) and the phosphorylation of PKA substrates, tyrosine residues and AMP-activated protein kinase (AMPK) were analyzed by Western blot. Moreover, intracellular sperm-specific glyceraldehyde 3-phosphatedehydrogenase (GAPDH) activity, 3'-5'-cyclic adenosine monophosphate (cAMP) and adenosine 5'-triphosphate (ATP) concentrations were assessed in boar sperm treated with Ca(2+). Results of the present study indicated that, under greater extracellular Ca(2+)concentrations (≥3.0mM), sperm motility and protein phosphorylation were inhibited. Interestingly, these changes were correlated with that of GAPDH activity, AMPK phosphorylation, cAMP and ATP concentrations. The negative effects of Ca(2+) on these intracellular processes were attenuated by addition of the calmodulin (CaM) inhibitor W7 and the inhibitor of calmodulin-dependent protein kinase (CaMK), KN-93. In the presence of greater extracellular Ca(2+), however, the phosphorylation pathway was suppressed by H-89. Taken together, these results suggested that Ca(2+) had a dual role in regulating boar sperm motility and protein phosphorylation due to the changes of cAMP and ATP concentrations, in response to cAMP-mediated signal transduction and the Ca(2+) signaling cascade. The present study provided some novel insights into the molecular mechanism underlying the effects of Ca(2+) on boar sperm as well as the involvement of energy metabolism in this mechanism.

  5. The initial phases of calcium and magnesium phosphates precipitated from solutions of high to medium concentrations

    Science.gov (United States)

    Abbona, F.; Madsen, H. E. Lundager; Boistelle, R.

    1986-04-01

    The precipitation of calcium and magnesium phosphates is performed at 25°C by mixing solutions of ammonium phosphate and solutions of calcium and magnesium chlorides under the condition [ P] = [ Ca] + [ Mg] in large pH intervals. Before any nucleation the phosphate concentration ranges from 0.50M to 0.01M. The phases first precipitated are CaHPO 4·2H 2O (brushite), CaHPO 4 (monetite), Ca 3(PO 4) 2· xH 2O (amorphous calcium phosphate), MgNH 4PO 4·6H 2O (struvite), and MgHPO 4·3H 2O (newberyite). The precipitation fields of each phase are determined and discussed as a function of pH, composition and supersaturation. The solutions are even supersaturated with respect to several other calcium phosphates but they never occur first even if their supersaturation is the highest.

  6. Reproducible extracellular vesicle size and concentration determination with tunable resistive pulse sensing

    Directory of Open Access Journals (Sweden)

    Frank A. W. Coumans

    2014-12-01

    Full Text Available Introduction: The size of extracellular vesicles (EVs can be determined with a tunable resistive pulse sensor (TRPS. Because the sensing pore diameter varies from pore to pore, the minimum detectable diameter also varies. The aim of this study is to determine and improve the reproducibility of TRPS measurements. Methods: Experiments were performed with the qNano system (Izon using beads and a standard urine vesicle sample. With a combination of voltage and stretch that yields a high blockade height, we investigate whether the minimum detected diameter is more reproducible when we configure the instrument targeting (a fixed stretch and voltage, or (b fixed blockade height. Results: Daily measurements with a fixed stretch and voltage (n=102 on a standard urine sample show a minimum detected vesicle diameter of 128±19 nm [mean±standard deviation; coefficient of variation (CV 14.8%]. The vesicle concentration was 2.4·109±3.8·109 vesicles/mL (range 1.4·108–1.8·1010. When we compared setting a fixed stretch and voltage to setting a fixed blockade height on 3 different pores, we found a minimum detected vesicle diameter of 118 nm (CV 15.5%, stretch, and 123 nm (CV 4.5%, blockade height. The detected vesicle concentration was 3.2–8.2·108 vesicles/mL with fixed stretch and 6.4–7.8·108 vesicles/mL with fixed blockade height. Summary/conclusion: Pore-to-pore variability is the cause of the variation in minimum detected size when setting a fixed stretch and voltage. The reproducibility of the minimum detectable diameter is much improved by setting a fixed blockade height.

  7. Effect of solute concentration on fibroin regulated biomineralization of calcium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kong Xiangdong [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Institute of Biochemistry, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Sun Xiaodan [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Cui Fuzhai [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)]. E-mail: cuifz@mail.tsinghua.edu.cn; Ma Chen [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2006-05-15

    In this paper we used UV/Visible method to study the effect of solute concentration on fibroin regulated biomineralization of calcium phosphate. During the reaction process, ultraviolet-visible spectrophotometer was used to track the extinction in the reaction solution. It is found that kinetics of the biomineralization can be strongly affected by the presence of fibroin. Fibroin with higher concentration has more positive effect on the biomineralization process. Under the appropriate reaction conditions, wave crest and wave trough appear in the kinetic curves of fibroin biomineralization. The wave crest and wave trough phenomenon is mainly related with the process of phase separation. X-ray Diffraction (XRD) result shows the calcium phosphate before the wave trough is mainly amorphous calcium phosphate, while after the wave trough crystal of hydroxyapatite (HA) and brushite (DCPD) are the mainly ingredients.

  8. Stimulation by leukotriene D4 of increases in the cytosolic concentration of calcium in dimethylsulfoxide-differentiated HL-60 cells.

    Science.gov (United States)

    Baud, L; Goetzl, E J; Koo, C H

    1987-10-01

    The C6-sulfidopeptide leukotrienes C4 (LTC4) and D4 (LTD4) evoked increases in the cytosolic concentration of intracellular calcium ([Ca+2]i) in dimethylsulfoxide-differentiated HL-60 cells, as assessed by the fluorescence of quin-2. The increases in [Ca+2]i reached a peak within 15-90 s, attained 50% of the maximum level at 1.2 nM LTD4 and 60 nM LTC4, were greater in maximal magnitude for LTD4 than LTC4, and subsided in 5-7 min. Flow cytometric evaluation of the LTD4-induced increases in [Ca+2]i, reflected in increases in the fluorescence of intracellular indo-1, revealed that a mean of 77% of differentiated HL-60 cells responded, as contrasted with lesser increases in only 50% of undifferentiated HL-60 cells. The capacity of pretreatment of HL-60 cells with LTD4 to prevent subsequent responses of [Ca+2]i to LTC4 and LTD4, and the finding that the serine-borate inhibitor of conversion of LTC4 to LTD4 suppressed concurrently both LTC4-induced rises in [Ca+2]i and increases in adherence to Sephadex G-25 indicated that the responses of HL-60 cells to LTC4 required conversion to LTD4. That pertussis toxin and a chemical antagonist of LTD4 reduced the [Ca+2]i response suggested a dependence on LTD4 receptors. The LTD4-induced increases in [Ca+2]i were dependent on extracellular calcium and diminished by lanthanum, but not affected by nifedipine nor associated with changes in membrane potential, as measured with the fluorescent probe 3,3'-dipentyloxacarbocyanine. Thus, the increase in [Ca+2]i in HL-60 cells, which is coupled to an increase in adherence, appears to involve LTD4 receptor-specific and voltage-independent calcium channels in the plasma membrane.

  9. Loss on drying, calcium concentration and pH of fluoride dentifrices

    Directory of Open Access Journals (Sweden)

    Arella Cristina Muniz Brito

    2015-01-01

    Full Text Available Introduction: Fluoride dentifrices containing calcium carbonate have advantages such as control of dental plaque and progression of dental caries, also contributing to oral hygiene, represent most dentifrices marketed in Brazil. Aim: To evaluate the physicochemical properties of seven fluoride dentifrices containing calcium carbonate in relation to hydrogen potential (pH, loss on drying and calcium concentration. Materials and Methods: Data collection was performed using the potentiometric method for pH ranges, gravimetric analysis for loss on drying and atomic absorption spectrometry for the concentration of calcium ions. All tests were performed in triplicate and the analysis was performed entirely at random according to one-way analysis of variance at 5% significance level. Results: The pH values were alkaline and ranged from 8.67 (Oral-B 123® to 10.03 (Colgate Mαxima Proteηγo Anticαries® . The results of loss on drying ranged from 33.81% (Oral-B 123® to 61.13% (Close Up® , with significant differences between brands tested. In relation to the calcium content, the highest and lowest concentrations were found in dentifrices Even® (155.55 g/kg and Colgate Ultra Branco® (129 g/kg, respectively, with significant difference (P < 0.05. Conclusion: Fluoride dentifrices analyzed showed alkaline pH and high levels of loss on drying and calcium concentration. However, these physicochemical characteristics differed according to the different brands tested.

  10. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.

    2012-01-01

    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein

  11. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.

    2012-01-01

    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutio

  12. Calcium intake and serum concentration in relation to risk of cardiovascular death in NHANES III.

    Directory of Open Access Journals (Sweden)

    Mieke Van Hemelrijck

    Full Text Available BACKGROUND: Evidence for an association between calcium intake and risk of cardiovascular death remains controversial. By assessing dietary intake, use of supplements, and serum levels of calcium, we aimed to disentangle this link in the third National Health and Nutrition Examination Survey (NHANES III. METHODS: Mortality linkage of NHANES III to death certificate data for those aged 17 years or older (n = 20,024 was used to estimate risk of overall cardiovascular death as well as death from ischemic heart disease (IHD, acute myocardial infarction (AMI, heart failure (HF, and cerebrovascular disease (CD with multivariate Cox proportional hazards regression analysis. RESULTS: About 10.0% of the population died of cardiovascular disease and the majority (5.4% died of IHD. There was increased risk of overall CVD death for those in the bottom 5% of serum calcium compared to those in the mid 90% (HR: 1.51 (95% CI: 1.03-2.22. For women there was a statistically significant increased risk of IHD death for those with serum calcium levels in the top 5% compared to those in the mid 90% (HR: 1.72 (95%CI: 1.13-2.61, whereas in men, low serum calcium was related to increased IHD mortality (HR: 2.32 (95% CI 1.14-3.01, Pinteraction: 0.306. No clear association with CVD death was observed for dietary or supplemental calcium intake. CONCLUSIONS: Calcium as assessed by serum concentrations is involved in cardiovascular health, though differential effects by sex may exist. No clear evidence was found for an association between dietary or supplementary intake of calcium and cardiovascular death.

  13. Impact of Testosterone, Zinc, Calcium and Magnesium Concentrations on Sperm Parameters in Subfertile Men

    Science.gov (United States)

    Aydemir, Birsen; Kiziler, Ali Riza; Onaran, Ilhan; Alici, Bülent; Özkara, Hamdi; Akyolcu, Mehmet Can

    2007-04-01

    To investigate the impact of testosterone, zinc, calcium and magnesium concentrations in serum and seminal plasma on sperm parameters. There were significant decrease in sperm parameters, serum and seminal plasma zinc levels in subfertile males. It indicates zinc has a essential role in male infertility; the determination the level of zinc during infertility investigation is recommended.

  14. Hydrate sodium calcium aluminosilicate does not reduce rumen lipopolysacharide concentrations in cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakorn, C.; Everts, H.; Vlaeminck, B.; Doekes, G.; Hendriks, W.H.

    2014-01-01

    The efficacy of hydrate sodium calcium aluminosilicate (HSCAS) to reduce the concentrations of free lipopolysaccharide (LPS) in rumen fluid of cows was investigated. Six, rumen-fistulated crossbred Holstein, non-pregnant, dry cows were randomly assigned to three experimental rations in a study with

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

    OpenAIRE

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

    2004-01-01

    The transfer of calcium from mother to milk during lactation is poorly understood. In this report, we demonstrate that parathyroid hormone–related protein (PTHrP) production and calcium transport in mammary epithelial cells are regulated by extracellular calcium acting through the calcium-sensing receptor (CaR). The CaR becomes expressed on mammary epithelial cells at the transition from pregnancy to lactation. Increasing concentrations of calcium, neomycin, and a calcimimetic compound suppre...

  16. Structure and function of ameloblastin as an extracellular matrix protein: adhesion, calcium binding, and CD63 interaction in human and mouse.

    Science.gov (United States)

    Zhang, Xu; Diekwisch, Thomas G H; Luan, Xianghong

    2011-12-01

    The functional significance of extracellular matrix proteins in the life of vertebrates is underscored by a high level of sequence variability in tandem with a substantial degree of conservation in terms of cell-cell and cell-matrix adhesion interactions. Many extracellular matrix proteins feature multiple adhesion domains for successful attachment to substrates, such as integrin, CD63, and heparin. Here we have used homology and ab initio modeling algorithms to compare mouse ameloblastin (mAMBN) and human ameloblastin (hABMN) isoforms and to analyze their potential for cell adhesion and interaction with other matrix molecules as well as calcium binding. Sequence comparison between mAMBN and hAMBN revealed a 26-amino-acid deletion in mAMBN, corresponding to a helix-loop-helix frameshift. The human AMBN domain (174Q-201G), homologous to the mAMBN 157E-178I helix-loop-helix region, formed a helix-loop motif with an extended loop, suggesting a higher degree of flexibility of hAMBN compared with mAMBN, as confirmed by molecular dynamics simulation. Heparin-binding domains, CD63-interaction domains, and calcium-binding sites in both hAMBN and mAMBN support the concept of AMBN as an extracellular matrix protein. The high level of conservation between AMBN functional domains related to adhesion and differentiation was remarkable when compared with only 61% amino acid sequence homology.

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

    NARCIS (Netherlands)

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

    1996-01-01

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

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

    NARCIS (Netherlands)

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

    1996-01-01

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

  19. Quantitative EFTEM mapping of near physiological calcium concentrations in biological specimens.

    Science.gov (United States)

    Aronova, M A; Kim, Y C; Pivovarova, N B; Andrews, S B; Leapman, R D

    2009-02-01

    Although electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) provides high sensitivity for measuring the important element, calcium, in biological specimens, the technique has been difficult to apply routinely, because of long acquisition times required. Here we describe a refinement of the complementary analytical technique of energy-filtered transmission electron microscopy (EFTEM), which enables rapid imaging of large cellular regions and measurement of calcium concentrations approaching physiological levels. Extraction of precise quantitative information is possible by averaging large numbers of pixels that are contained in organelles of interest. We employ a modified two-window approach in which the behavior of the background signal in the EELS spectrum can be modeled as a function of specimen thickness t expressed in terms of the inelastic mean free path lambda. By acquiring pairs of images, one above and one below the Ca L(2,3) edge, together with zero-loss and unfiltered images, which are used to determine a relative thickness (t/lambda) map, it is possible to correct the Ca L(2,3) signal for plural scattering. We have evaluated the detection limits of this technique by considering several sources of systematic errors and applied this method to determine mitochondrial total calcium concentrations in freeze-dried cryosections of rapidly frozen stimulated neurons. By analyzing 0.1 microm2 areas of specimen regions that do not contain calcium, it was found that the standard deviation in the measurement of Ca concentrations was about 20 mmol/kg dry weight, corresponding to a Ca:C atomic fraction of approximately 2 x 10(-4). Calcium concentrations in peripheral mitochondria of recently depolarized, and therefore stimulated and Ca loaded, frog sympathetic neurons were in reasonable agreement with previous data.

  20. Quantitative EFTEM mapping of near physiological calcium concentrations in biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Aronova, M.A. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 9000 Rockville Pike, Bethesda, MD 20892 (United States); Kim, Y.C. [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Pivovarova, N.B.; Andrews, S.B. [Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892 (United States); Leapman, R.D. [Laboratory of Bioengineering and Physical Science, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bldg. 13, Rm. 3N17, 9000 Rockville Pike, Bethesda, MD 20892 (United States)], E-mail: leapmanr@mail.nih.gov

    2009-02-15

    Although electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) provides high sensitivity for measuring the important element, calcium, in biological specimens, the technique has been difficult to apply routinely, because of long acquisition times required. Here we describe a refinement of the complementary analytical technique of energy-filtered transmission electron microscopy (EFTEM), which enables rapid imaging of large cellular regions and measurement of calcium concentrations approaching physiological levels. Extraction of precise quantitative information is possible by averaging large numbers of pixels that are contained in organelles of interest. We employ a modified two-window approach in which the behavior of the background signal in the EELS spectrum can be modeled as a function of specimen thickness t expressed in terms of the inelastic mean free path {lambda}. By acquiring pairs of images, one above and one below the Ca L{sub 2,3} edge, together with zero-loss and unfiltered images, which are used to determine a relative thickness (t/{lambda}) map, it is possible to correct the Ca L{sub 2,3} signal for plural scattering. We have evaluated the detection limits of this technique by considering several sources of systematic errors and applied this method to determine mitochondrial total calcium concentrations in freeze-dried cryosections of rapidly frozen stimulated neurons. By analyzing 0.1 {mu}m{sup 2} areas of specimen regions that do not contain calcium, it was found that the standard deviation in the measurement of Ca concentrations was about 20 mmol/kg dry weight, corresponding to a Ca:C atomic fraction of approximately 2x10{sup -4}. Calcium concentrations in peripheral mitochondria of recently depolarized, and therefore stimulated and Ca loaded, frog sympathetic neurons were in reasonable agreement with previous data.

  1. Histamine release induced from rat mast cells by the ionophore A23187 in the absence of extracellular calcium

    DEFF Research Database (Denmark)

    Johansen, Torben

    1980-01-01

    Isolated rat mast cells were used to study whether ionophore A23187 could induce histamine release by mobilizing cellular calcium. The histamine release was a slow process which was completed after about 20 min incubation with A23187. The A23187-induced histamine release was inhibited after...... incubation of the cells with EDTA for 1 h in a 37 degrees C water bath in calcium-free medium. Reintroduction of calcium in excess of EDTA induced the release of histamine. The observations suggest that A23187 can induce histamine release by mobilizing a cellular pool of calcium....

  2. Effects of endothelin- 1 on hepatic stellate cell proliferation, collagen synthesis and secretion, intracellular free calcium concentration

    Institute of Scientific and Technical Information of China (English)

    Chuan-Yong Guo; Jian-Ye Wu; Yun-Bin Wu; Min-Zhang Zhong; Han-Ming Lu

    2004-01-01

    AIM: To explore the effects of endothelin-1(ET-1) on hepatic stellate cells (HSCs) DNA uptake, DNA synthesis, collagen synthesis and secretion, inward whole-cell calcium concentration ([Ca2+]i) as well as the blocking effect of verapamil on ET-1-stimulated release of inward calcium (Ca2+) of HSC in vitro.METHODS: Rat hepatic stellate cells (HSCs) were isolated and cultivated. 3H-TdR and 3H-proline incorporation used for testing DNA uptake and synthesis, collagen synthesis and secretion of HSCs cultured in vitro; Fluorescent calciumindicator Fura-2/AM was used to measure [Ca2+]i inward HSCs.RESULTS: ET-1 at the concentration of 5×10-8 mol/L,caused significant increase both in HSC DNA synthesis(2 247±344 cpm, P<0.05) and DNA uptake (P<0.05) whencompared with the control group. ET-1 could also increase collagen synthesis (P<0.05 vs control group) and collagen secretion (P<0.05 vs control group). Besides, inward HSC [Ca2+]i reached a peak concentration (422±98 mol/L, P<0.001)at 2 min and then went down slowly to165±51 mol/L(P<0.01) at 25 min from resting state (39±4 mol/L)aftertreated with ET-1. Verapamil (5 mol/L) blocked ET-1activated [Ca2+]i inward HSCs compared with control group(P<0.05). Fura-2/AM loaded HSC was suspended in no Ca2+ buffer containing 1 mol/L EGTA, 5 min later, 10-8 mol/Lof ET-1 was added, [Ca2+]i inward HSCs rose from restingstate to peak 399±123 mol/L, then began to come downby the time of 20 min. It could also raise [Ca2+]i inwardHSCs even without Ca2+ in extracellular fluid, and had a remarkable dose-effect relationship(P<0.05). Meanwhile, verapamil could restrain the action of ET-1(P<0.05). CONCLUSION: Actions of ET-1 on collagen metabolism of HSCs may depend on the transportation of inward wholecell calcium.

  3. The concentration of extracellular superoxide dismutase in plasma is maintained by LRP-mediated endocytosis

    DEFF Research Database (Denmark)

    Petersen, Steen V; Thøgersen, Ida B; Valnickova, Zuzana;

    2010-01-01

    In this study, we show that human extracellular superoxide dismutase (EC-SOD) binds to low-density lipoprotein receptor-related protein (LRP). This interaction is most likely responsible for the removal of EC-SOD from the blood circulation via LRP expressed in liver tissue. The receptor recogniti...

  4. [Serum calcium and phosphorus concentration and alkaline phosphatase activity in healthy children during growth and development].

    Science.gov (United States)

    Savić, Ljiljana; Savić, Dejan

    2008-01-01

    Many changes happen during growth and development in an organism as a result of important hormon changes, especially biohumoral ones. These changes make a problem when interpreting biochemical results in pediatric population. The most important changes are intensive calcium and phosphorus metabolic turnover in bone tissue with changes in alkaline phosphatase activity as a result of osteoblast activity. The aim of this study was to follow the serum calcium and phosphorus concentration and alkaline phosphatase activity in children 1-15 years old in different growth and development period and of different sexes and to fortify the influence of growth and development dynamics on biohumoral status in healthy male and female children. We evaluated 117 healthy children of both sexes from 1-15 years of age and divided them into three age groups: 1-5, 6-10 and 11-15 years. We followed the serum calcium and phosphorus concentration and alkaline phosphatase activity in different groups and in different sexes. Our investigation found significantly higher values of serum calcium in boys than in girls with no important changes between the age groups and significantly higher values of serum phosphorus in the youngest age group in all children and in different sexes with no important sex differences. Alkaline phosphatase activity followed the growth spurt and was the biggest in 6-10 years group in girls and in 11-15 years group in boys.

  5. The polybasic lysine-rich domain of plasma membrane-resident STIM1 is essential for the modulation of store-operated divalent cation entry by extracellular calcium.

    Science.gov (United States)

    Jardin, Isaac; Dionisio, Natalia; Frischauf, Irene; Berna-Erro, Alejandro; Woodard, Geoffrey E; López, José J; Salido, Ginés M; Rosado, Juan A

    2013-05-01

    STIM1 acts as an endoplasmic reticulum Ca(2+) sensor that communicates the filling state of the intracellular stores to the store-operated channels. In addition, STIM1 is expressed in the plasma membrane, with the Ca(2+) binding EF-hand motif facing the extracellular medium; however, its role sensing extracellular Ca(2+) concentrations in store-operated Ca(2+) entry (SOCE), as well as the underlying mechanism remains unclear. Here we report that divalent cation entry stimulated by thapsigargin (TG) is attenuated by extracellular Ca(2+) in a concentration-dependent manner. Expression of the Ca(2+)-binding defective STIM1(D76A) mutant did not alter the surface expression of STIM1 but abolishes the regulation of divalent cation entry by extracellular Ca(2+). Orai1 and TRPC1 have been shown to play a major role in SOCE. Expression of the STIM1(D76A) mutant did not alter Orai1 phosphoserine content. TRPC1 silencing significantly attenuated TG-induced Mn(2+) entry. Expression of the STIM1(K684,685E) mutant impaired the association of plasma membrane STIM1 with TRPC1, as well as the regulation of TG-induced divalent cation entry by extracellular Ca(2+), which suggests that TRPC1 might be involved in the regulation of divalent cation entry by extracellular Ca(2+) mediated by plasma membrane-resident STIM1. Expression of the STIM1(D76A) or STIM1(K684,685E) mutants reduced store-operated divalent cation entry and resulted in loss of dependence on the extracellular Ca(2+) concentration, providing evidence for a functional role of plasma membrane-resident STIM1 in the regulation of store-operated divalent cation entry, which at least involves the EF-hand motif and the C-terminal polybasic lysine-rich domain. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. [Concentrations of calcium, magnesium, sodium and potassium in human milk and infant formulas].

    Science.gov (United States)

    Rodríguez Rodríguez, E M; Sanz Alaejos, M; Díaz Romero, C

    2002-12-01

    Concentrations of calcium, magnesium, sodium and potassium were determined in 55 samples of mature human milk from Canary women and 5 samples of powdered infant formula. According to the literature our data fell within the normal intervals described for each kind of milk. The mean concentration of Ca, Mg, Na y K of powdered infant formula was higher than those concentrations found in the human milks. Significant differences among the concentrations of Ca, Mg and Na for the milks of the considered mothers were observed. Only the Ca intakes for infants fed with human milk were lower than those requirements recommended by the Food and Nutrition Board (1989). However, the infants fed with powdered infant formula had an adequate intake of all the studied metals. A progressive decrease of the Na, K and Ca concentrations with the lactation stage was observed. Maternal age, parity and sex of the newborns did not affect the metal concentrations significantly.

  7. CALCIUM, CREATININE AND URINARY PHOSPHATE/CREATININE RATIO CONCENTRATIONS IN NEONATES OF VARIOUS GESTATIONAL AGES

    Directory of Open Access Journals (Sweden)

    O. I. Fomina

    2014-01-01

    Full Text Available Objective: specify peculiarities of calcium and phosphates excretion in neonates of various gestational ages and types of feeding in neonatal period. Patients and methods. Calcium-creatinine (Ca/Cr and phosphate-creatinine (P/Cr ratio concentrations were determined in 96 healthy neonates of 38-40 weeks of gestational age and 146 premature infants of 28-37 weeks of gestational age of various types of feeding. Results. The Ca/Cr ratio concentration in healthy term infants in the early neonatal period amounted to 0.9-2.2 (median – 1.8, the P/Cr ratio concentration – 0.8-2.1 (median – 1.6. The Ca/Cr ratio concentration in premature infants (28-37 weeks of gestational age amounted to 0.9-2.4 (median – 1.9, which is comparable to this parameter’s value in term infants. The P/Cr ratio concentration amounted to 0.7-3.1 (median – 2.4, which exceeds this parameter’s value in term infants. The lesser the gestational age and birth weight, the higher the Ca/Cr and P/Cr ratio concentrations. The authors revealed hypercalciuria and hyperphosphaturia in premature infants with a very low body weight fed with specialized formulas. Conclusions. Use of specialized formulas in small premature infants (gestational age < 33 weeks with VLBW results in excessive calcium and phosphates excretion. It is reasonable to monitor their concentrations using a non-invasive and informative method of determining Ca/Cr and P/Cr ratios. Feeding of premature infants with BW > 1,500 g with breast milk only (in case of the mother’s adequate lactation allows avoiding hypercalciuria and hyperphosphaturia and preventing risk of a renal pathology. 

  8. Juice of Bryophyllum pinnatum (Lam.) inhibits oxytocin-induced increase of the intracellular calcium concentration in human myometrial cells.

    Science.gov (United States)

    Simões-Wüst, A P; Grãos, M; Duarte, C B; Brenneisen, R; Hamburger, M; Mennet, M; Ramos, M H; Schnelle, M; Wächter, R; Worel, A M; von Mandach, U

    2010-10-01

    The use of preparations from Bryophyllum pinnatum in tocolysis is supported by both clinical (retrospective comparative studies) and experimental (using uterus strips) evidence. We studied here the effect of B. pinnatum juice on the response of cultured human myometrial cells to stimulation by oxytocin, a hormone known to be involved in the control of uterine contractions by increasing the intracellular free calcium concentration ([Ca2+]i). In this work, [Ca2+]i was measured online during stimulation of human myometrial cells (hTERT-C3 and M11) with oxytocin, which had been pre-incubated in the absence or in the presence of B. pinnatum juice. Since no functional voltage-gated Ca2+ channels could be detected in these myometrial cells, the effect of B. pinnatum juice was as well studied in SH-SY5Y neuroblastoma cells, which are known to have such channels and can be depolarised with KCl. B. pinnatum juice prevented the oxytocin-induced increase in [Ca2+]i in hTERT-C3 human myometrial cells in a dose-dependent manner, achieving a ca. 80% inhibition at a 2% concentration. Comparable results were obtained with M11 human primary myometrial cells. In hTERT-C3 cells, prevention of the oxytocin-induced increase in [Ca2+]i was independent of the extracellular Ca2+ concentration and of voltage-dependent Ca2+-channels. B. pinnatum juice delayed, but did not prevent the depolarization-induced increase in [Ca2+]i in SH-SY5Y cells. Taken together, the data suggest a specific and concentration-dependent effect of B. pinnatum juice on the oxytocin signalling pathway, which seems to corroborate its use in tocolysis. Such a specific mechanism would explain the rare and minor side-effects in tocolysis with B. pinnatum as well as its high therapeutic index.

  9. Does Salivary Calcium and Phosphate Concentrations Adequately Reflect Bone Mineral Density in Patients with Chronic Periodontitis?

    Science.gov (United States)

    Moghadam, Somaye Ansari; Zakeri, Zahra; Fakour, Sirous Risbaf; Moghaddam, Alireza Ansari

    2016-10-01

    Periodontitis is the inflammation of the periodontal supporting tissues. The response of periodontal tissues to local bacteria leads to bone resorption and destruction of periodontal junction. Given the possible association between periodontitis and low bone mineral density, the aim of present study was to find if measurement of salivary biomarkers as a less invasive method, can provide an appropriate screening method for assessment of bone mineral density in patients with chronic periodontitis? A case-control study was conducted on 53 people, including 28 patients with severe chronic periodontitis and 25 healthy people between April 2014 to March 2015 in Zahedan (southeast of Iran). Following Periodontal examination, salivary samples were collected, and the concentration of salivary calcium and phosphate were measured and reported as mg/dl. Bone mineral density of participants was measured using dual energy x-ray absorptiometry and reported as gr/cm2. No significant association was found between concentrations of salivary calcium and phosphate levels with bone mineral density in either healthy people or in patients with severe chronic periodontitis, despite a significant bone density reduction (in the femur neck and lumbar spine L2-L4) in the periodontitis group compared to healthy people (P=0.006, and P=0.009 respectively). Concentration of salivary calcium and phosphate do not appear to be good indicators of bone mineral density. Further prospective studies with larger sample size are recommended.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

  11. The calcium concentration of public drinking waters and bottled mineral waters in Spain and its contribution to satisfying nutritional needs

    Directory of Open Access Journals (Sweden)

    Isidro Vitoria

    2014-07-01

    Full Text Available Introduction: A sufficient intake of calcium enables correct bone mineralization. The bioavailability of calcium in water is similar to that in milk. Objective: To determine the concentration of calcium in public drinking water and bottled mineral water. Methods: We used ion chromatography to analyse the calcium concentrations of public drinking waters in a representative sample of 108 Spanish municipalities (21,290,707 people and of 109 natural mineral waters sold in Spain, 97 of which were produced in Spain and 12 of which were imported. Results: The average calcium concentration of public drinking waters was 38.96 ± 32.44 mg/L (range: 0.40159.68 mg/L. In 27 municipalities, the water contained 50-100 mg/L of calcium and in six municipalities it contained over 100 mg/L. The average calcium concentration of the 97 Spanish natural mineral water brands was 39.6 mg/L (range: 0.6-610.1 mg/L. Of these, 34 contained 50-100 mg/L of calcium and six contained over 100 mg/L. Of the 12 imported brands, 10 contained over 50 mg/L. Assuming water consumption is as recommended, water containing 50-100 mg/L of calcium provides 5.4-12.8% of the recommended intake of calcium for children aged one to thirteen, up to 13.6% for adolescents, 5.8-17.6% for adults, and up to 20.8% for lactating mothers. Water with 100-150 mg/L of calcium provides 10-31% of the recommended dietary allowance, depending on the age of the individual. Discussion: Public drinking water and natural mineral water consumption in a third of Spanish cities can be considered an important complementary source of calcium.

  12. Dynamic changes in calcium and phosphate plasma concentrations in the patients on peritoneal dialysis

    Directory of Open Access Journals (Sweden)

    Jovanović Nataša

    2006-01-01

    Full Text Available Background/Aim. The disturbances of active forms of vitamin D synthesis and disturbances in calcium and posphate metabolism develop early in chronic renal failure, when creatinine clearance is about 30 ml/min. Chronic hemodialysis and peritoneal dialysis only partially correct the biochemical environment of patients on chronic renal replacement therapy because of end-stage renal disease. These dialysis modalities can’t significantly affect the endocrine disturbances of chronic renal failure and they have minimal modulatory effect. The management of disturbed calcium (Ca and phosphate (P metabolism and the maintainance of Ca × P product below 4.4 mmol/l thanks to the use of dialysate solutions with the appropriate calcium concentration and the careful dosage of phosphate binders, calcium and active vitamin D metabolits, are extremely important for the prevention of renal osteodystrophy, secondary hyperparathyroidism as well as low-bone turnover disease. The aim of the study was to analyze the plasma levels of calcium, phosphate, albumin, alkaline phosphatase and parathormon (PTH in 58 patients who were treated with continuous ambulatory peritoneal dialysis (CAPD from March to August 2003. The use of phosphate binders and the substitution with active vitamin D metabolits were also analyzed. Methods. We examined 58 patients, 30 males and 28 female, mean-age 52 years (range, 26-78 years, affected by end-stage renal disease of the different leading cause. The average time on peritoneal dialysis program was 20 months (2-66 months. Most of the patients were treated by CAPD, while only few of them performed automatic, cyclic or intermittent peritoneal dialysis. Most of the patients used a dialysate with 1.75 mmol/l calcium concentration. Results. The study showed that our patients on chronic CAPD program during several months had normal calcemia, phosphatemia and the level of alkaline phosphatase, and that they had Ca × P product in the recommended

  13. Formaldehyde increases intracellular calcium concentration in primary cultured hippocampal neurons partly through NMDA receptors and T-type calcium channels

    Institute of Scientific and Technical Information of China (English)

    Ye-Nan Chi; Xu Zhang; Jie Cai; Feng-Yu Liu; Guo-Gang Xing; You Wan

    2012-01-01

    Objective Formaldehyde at high concentrations is a contributor to air pollution.It is also an endogenous metabolic product in cells,and when beyond physiological concentrations,has pathological effects on neurons.Formaldehyde induces mis-folding and aggregation of neuronal tau protein,hippocampal neuronal apoptosis,cognitive impairment and loss of memory functions,as well as excitation of peripheral nociceptive neurons in cancer pain models.Intracellular calcium ([Ca2+]i) is an important intracellular messenger,and plays a key role in many pathological processes.The present study aimed to investigate the effect of formaldehyde on [Ca2+]i and the possible involvement of N-methyl-D-aspartate receptors (NMDARs) and T-type Ca2+ channels on the cell membrane.Methods Using primary cultured hippocampal neurons as a model,changes of [Ca2+]i in the presence of formaldehyde at a low concentration were detected by confocal laser scanning microscopy.Results Formaldehyde at 1 mmol/L approximately doubled [Ca2+]i.(2R)-amino-5-phosphonopentanoate (AP5,25 μtmol/L,an NMDAR antagonist) and mibefradil (MIB,1 μtmol/L,a T-type Ca2+ channel blocker),given 5 min after formaldehyde perfusion,each partly inhibited the formaldehyde-induced increase of [Ca2+]i,and this inhibitory effect was reinforced by combined application of AP5 and MIB.When applied 3 min before formaldehyde perfusion,AP5 (even at 50 μmol/L) did not inhibit the formaldehyde-induced increase of [Ca2+]i,but MIB (1 μmol/L) significantly inhibited this increase by 70%.Conclusion These results suggest that formaldehyde at a low concentration increases [Ca2+]i in cultured hippocampal neurons; NMDARs and T-type Ca2+ channels may be involved in this process.

  14. Quantitative proteomic analysis reveals metabolic alterations, calcium dysregulation, and increased expression of extracellular matrix proteins in laminin α2 chain-deficient muscle.

    Science.gov (United States)

    de Oliveira, Bruno Menezes; Matsumura, Cintia Y; Fontes-Oliveira, Cibely C; Gawlik, Kinga I; Acosta, Helena; Wernhoff, Patrik; Durbeej, Madeleine

    2014-11-01

    Congenital muscular dystrophy with laminin α2 chain deficiency (MDC1A) is one of the most severe forms of muscular disease and is characterized by severe muscle weakness and delayed motor milestones. The genetic basis of MDC1A is well known, yet the secondary mechanisms ultimately leading to muscle degeneration and subsequent connective tissue infiltration are not fully understood. In order to obtain new insights into the molecular mechanisms underlying MDC1A, we performed a comparative proteomic analysis of affected muscles (diaphragm and gastrocnemius) from laminin α2 chain-deficient dy(3K)/dy(3K) mice, using multidimensional protein identification technology combined with tandem mass tags. Out of the approximately 700 identified proteins, 113 and 101 proteins, respectively, were differentially expressed in the diseased gastrocnemius and diaphragm muscles compared with normal muscles. A large portion of these proteins are involved in different metabolic processes, bind calcium, or are expressed in the extracellular matrix. Our findings suggest that metabolic alterations and calcium dysregulation could be novel mechanisms that underlie MDC1A and might be targets that should be explored for therapy. Also, detailed knowledge of the composition of fibrotic tissue, rich in extracellular matrix proteins, in laminin α2 chain-deficient muscle might help in the design of future anti-fibrotic treatments. All MS data have been deposited in the ProteomeXchange with identifier PXD000978 (http://proteomecentral.proteomexchange.org/dataset/PXD000978).

  15. The hemodynamic effect of calcium ion concentration in the infusate during predilution hemofiltration in chronic renal failure

    DEFF Research Database (Denmark)

    Karamperis, N.; Sloth, E.; Jensen, Jens Dam

    2005-01-01

    BACKGROUND: It is the prevailing view that convective dialysis techniques stabilize blood pressure. Calcium concentration in the substitution fluid may be important in this respect. The aim of this study is to investigate the influence of calcium ion concentration in the substitution fluid...... on hemodynamic stability during predilution hemofiltration (HF). METHODS: We conducted a randomized, crossover, blinded, controlled trial with 12 stable long-term hemodialysis patients without diabetes. Each patient was randomly assigned to substitution fluid with a calcium ion (iCa) concentration of 2.5 m...

  16. Effect of chronic elevation of plasma calcium concentration by PTH or vitamin D3on blood pressure and hypotensive activity of nifedipine in rats

    NARCIS (Netherlands)

    Jonkman, F.A.M.; Thoolen, M.J.M.C.; Wilffert, B.

    1984-01-01

    The influence of a chronically elevated total plasma calcium concentration on blood pressure and heart rate was investigated in conscious normotensive rats. The plasma calcium concentration was elevated by continuous subcutaneous infusion with parathormone (PTH) after parathyreoidectomy, and by oral

  17. Meta-Analysis of Genome-Wide Association Studies Identifies Six New Loci for Serum Calcium Concentrations

    NARCIS (Netherlands)

    C.M. O'Seaghdha (Conall); H. Wu (Hongsheng); Q. Yang (Qiong); K. Kapur (Karen); I. Guessous (Idris); P. Zuber (Patrick); A. Köttgen (Anna); C. Stoudmann (Candice); A. Teumer (Alexander); Z. Kutalik (Zoltán); M. Mangino (Massimo); A. Dehghan (Abbas); W. Zhang (Weihua); G. Eiriksdottir (Gudny); G. Li (Guo); T. Tanaka (Toshiko); L. Portas (Laura); L.M. Lopez (Lorna); C. Hayward (Caroline); K. Lohman (Kurt); K. Matsuda (Koichi); S. Padmanabhan (Sandosh); D. Firsov (Dmitri); R. Sorice; S. Ulivi (Shelia); A.C. Brockhaus (A. Catharina); M.E. Kleber (Marcus); A. Mahajan (Anubha); F.D.J. Ernst (Florian); V. Gudnason (Vilmundur); L.J. Launer (Lenore); A. Mace (Aurelien); E.A. Boerwinkle (Eric); D.E. Arking (Dan); C. Tanikawa (Chizu); Y. Nakamura (Yusuke); M.J. Brown (Morris); J.-M. Gaspoz (Jean-Michel); J.-M. Theler (Jean-Marc); D.S. Siscovick (David); B.M. Psaty (Bruce); S.M. Bergmann (Sven); P. Vollenweider (Peter); V. Vitart (Veronique); A.F. Wright (Alan); T. Zemunik (Tatijana); M. Boban (Mladen); I. Kolcic (Ivana); P. Navarro (Pau); E.M. Brown (Edward); K. Estrada Gil (Karol); J. Ding (Jinhui); T.B. Harris (Tamara); S. Bandinelli (Stefania); D.G. Hernandez (Dena); A. Singleton (Andrew); S. Girotto; D. Ruggiero; A.P. d' Adamo (Adamo Pio); A. Robino (Antonietta); T. Meitinger (Thomas); C. Meisinger (Christa); G. Davies (Gail); J.M. Starr (John); J.C. Chambers (John); B.O. Boehm (Bernhard); B. Winkelmann; J. Huang (Jian); D. Murgia (Daniela); S.H. Wild (Sarah); H. Campbell (Harry); A.D. Morris (Andrew); O.H. Franco (Oscar); A. Hofman (Albert); A.G. Uitterlinden (André); F. Rivadeneira Ramirez (Fernando); U. Vol̈ker (Uwe); M. Hannemann (Mario); R. Biffar (Reiner); W. Hoffmann (Wolfgang); S.-Y. Shin; P. Lescuyer (Pierre); H. Henry (Hughes); C. Schurmann (Claudia); P. Munroe (Patricia); P. Gasparini (Paolo); N. Pirastu (Nicola); M. Ciullo; C. Gieger (Christian); W. März (Winfried); L. Lind (Lars); T.D. Spector (Timothy); G.D. Smith; I. Rudan (Igor); J.F. Wilson (James); O. Polasek (Ozren); I.J. Deary (Ian); M. Pirastu (Mario); L. Ferrucci (Luigi); Y. Liu (Yongmei); B. Kestenbaum (Bryan); J.S. Kooner (Jaspal); J.C.M. Witteman (Jacqueline); M. Nauck (Matthias); W.H.L. Kao (Wen); H. Wallaschofski (Henri); O. Bonny (Olivier); C. Fox (Craig); M. Bochud (Murielle)

    2013-01-01

    textabstractCalcium is vital to the normal functioning of multiple organ systems and its serum concentration is tightly regulated. Apart from CASR, the genes associated with serum calcium are largely unknown. We conducted a genome-wide association meta-analysis of 39,400 individuals from 17 populati

  18. Ionized calcium concentration in horses with surgically managed gastrointestinal disease: 147 cases (1988-1990).

    Science.gov (United States)

    Dart, A J; Snyder, J R; Spier, S J; Sullivan, K E

    1992-10-15

    Packed cell volume, total plasma protein, serum sodium, potassium, and ionized Ca2+ concentrations, and blood pH were determined at the time of admission and following surgery in 147 horses with acute abdominal crisis. Horses were allotted to 3 categories on the basis of the surgical lesion: (1) nonstrangulating obstruction of the ascending or descending colon (category A, n = 76), (2) strangulating and nonstrangulating infarction of the cecum or ascending colon (category B, n = 37), and (3) strangulating and nonstrangulating infarction of the small intestine (category C, n = 25). Horses with low serum ionized Ca2+ concentration following surgery were given 23% calcium gluconate (100 to 300 ml) IV to effect, and ionized Ca2+ concentration was determined following treatment. The serum ionized Ca2+ concentrations of horses in categories A, B, and C before and after surgery were lower than our normal laboratory reference range. Prior to surgery, serum ionized Ca2+ concentration measured from horses in category B and C was lower than that in horses in category A. There was no difference in ionized Ca2+ concentration in serum samples obtained before surgery in horses from category B and C, and in serum samples obtained following surgery. There was a decrease in ionized Ca2+ concentration during surgery in horses in category A. There was no change between preoperative and postoperative ionized Ca2+ concentration in the samples obtained from horses in category B and C. After calcium gluconate administration, all horses with low serum ionized Ca2+ after surgery had concentrations within our normal range. Measurement of serum ionized Ca2+ in horses with an acute abdominal crisis is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Measurement of intracellular Ca2+ concentration in single cells using ratiometric calcium dyes.

    Science.gov (United States)

    Srikanth, Sonal; Gwack, Yousang

    2013-01-01

    Measurement of intracellular Ca(2+) concentration ([Ca(2+)](i)) is useful to study the upstream and downstream events of Ca(2+) signaling. Ca(2+)-binding proteins including EF-hand-containing proteins are important downstream effector molecules after an increase of [Ca(2+)](i). Conversely, these proteins can also act as key modulators for regulation of [Ca(2+)](i) by sensing the Ca(2+) levels in the intracellular organelles and cytoplasm. Here we describe a single-cell Ca(2+) imaging technique that was used to measure the intracellular Ca(2+) levels to examine the function of Ca(2+)-binding proteins, STIM1 and Calcium release-activated Calcium channel regulator 2A (CRACR2A), using ratiometric Ca(2+) dye Fura-2 in adherent and non-adherent cells.

  20. Effects of calcium ion concentration on starch hydrolysis of barley alpha-amylase isozymes.

    Science.gov (United States)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee; Jang, Myoung-Uoon; Park, Jung-Mi; Yi, Ah-Rum; Svensson, Birte; Kim, Tae-Jip

    2008-04-01

    Barley alpha-amylase genes, amy1 and amy2, were separately cloned into the expression vector of pPICZalphaA and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates.

  1. Effects of calcium ion concentration on starch hydrolysis of barley α-amylase isozymes

    DEFF Research Database (Denmark)

    Yuk, Jeong-Bin; Choi, Seung-Ho; Lee, Tae-Hee;

    2008-01-01

    Barley (x-amylase genes, amyl and amy2, were separately cloned into the expression vector of pPICZ alpha A and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result...... in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However......, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates....

  2. Electric pulses: a flexible tool to manipulate cytosolic calcium concentrations and generate spontaneous-like calcium oscillations in mesenchymal stem cells

    Science.gov (United States)

    de Menorval, Marie-Amelie; Andre, Franck M.; Silve, Aude; Dalmay, Claire; Français, Olivier; Le Pioufle, Bruno; Mir, Lluis M.

    2016-01-01

    Human adipose mesenchymal stem cells (haMSCs) are multipotent adult stem cells of great interest in regenerative medicine or oncology. They present spontaneous calcium oscillations related to cell cycle progression or differentiation but the correlation between these events is still unclear. Indeed, it is difficult to mimic haMSCs spontaneous calcium oscillations with chemical means. Pulsed electric fields (PEFs) can permeabilise plasma and/or organelles membranes depending on the applied pulses and therefore generate cytosolic calcium peaks by recruiting calcium from the external medium or from internal stores. We show that it is possible to mimic haMSCs spontaneous calcium oscillations (same amplitude, duration and shape) using 100 μs PEFs or 10 ns PEFs. We propose a model that explains the experimental situations reported. PEFs can therefore be a flexible tool to manipulate cytosolic calcium concentrations. This tool, that can be switched on and off instantaneously, contrary to chemicals agents, can be very useful to investigate the role of calcium oscillations in cell physiology and/or to manipulate cell fate. PMID:27561994

  3. Multidrug resistance-associated protein 1 decreases the concentrations of antiepileptic drugs in cortical extracellular fluid in amygdale kindling rats

    Institute of Scientific and Technical Information of China (English)

    Ying-hui CHEN; Cui-cui WANG; Xia XIAO; Li WEI; Guoxiong XU

    2013-01-01

    Aim:To investigate whether multidrug resistance-associated protein 1 (MRP1) was responsible for drug resistence in refractory epilepsy in amygdale kindling rats.Methods:Rat amygdale kindling was used as a model of refractory epilepsy.The expression of MRP1 mRNA and protein in the brains was examined using RT-PCR and Western blot.MRP1-positive cells in the cortex and hippocampus were studied with immunohistochemical staining.The rats were intraperitoneally injected with phenytoin (50 mg/kg) or carbamazepine (20 mg/kg),and their concentrations in the cortical extracellular fluid were measured using microdialysis and HPLC.Probenecid,a MRP1 inhibitor (40 mmol/L,50 μL) was administered through an inflow tube into the cortex 30 min before injection of the antiepileptic drugs.Results:The expression of MRP1 mRNA and protein was significantly up-regulated in the cortex and hippocampus in amygdale kindling rats compared with the control group.Furthermore,the number of MRP1-positive cells in the cortex and hippocampus was also significantly increased in amygdale kindling rats.Microdialysis studies showed that the concentrations of phenytoin and carbamazepine in the cortical extracellular fluid were significantly decreased in amygdale kindling rats.Pre-administration of probenecid could restore the concentrations back to their control levels.Conclusion:Up-regulation of MRP1 is responsible for the resistance of brain cells to antiepileptic drugs in the amygdale kindling rats.

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

    DEFF Research Database (Denmark)

    Plesner, Bitten; Westh, Peter; Hvidt, Søren

    2011-01-01

    The effects of calcium chloride on the structural, kinetic and thermal stability of recombinant human factor VIIa (rFVIIa) were investigated using rFVIIa and two GlycoPEGylated recombinant human FVIIa derivatives, a linear 10 kDa PEG and a branched 40 kDa PEG, respectively. Three different CaCl(2...... scanning calorimetry (DSC) and circular dichroism (CD), and aggregation behaviour, measured by light scattering (LS), were affected by the increasing calcium concentration. Increasing the CaCl(2) concentration from 10mM to 35 mM resulted in a decrease in the apparent unfolding temperature, T(m), of r......FVIIa compounds was practically independent of the CaCl(2) concentration. From the obtained results, it is concluded that GlycoPEGylation postpones the calcium induced thermal destabilisation of rFVIIa, and a much higher calcium concentration also postpones the thermally induced aggregation of r...

  5. Concentration determination of extracellular and intracellular red pigments produced by Monascus sp

    Directory of Open Access Journals (Sweden)

    Patricia Sanae Hamano

    2005-06-01

    Full Text Available In this work red pigments production was evaluated (by spectrophotometry in semi-synthetic medium by rotary shaker cultures, utilizing seven strains of Monascus sp. The strains isolated at LEB/DEQ/EPUSP had a absorbance average of extracellular red pigments higher than the others strains (13.0 and 9.6 U, respectively and the specific production of extracellular red pigments was from 1.7 until 3.5 times higher than the specific production of intracellular ones.Monascus sp. é um fungo filamentoso cuja principal aplicação industrial está relacionada à sua capacidade de produzir pigmentos vermelhos, utilizados como corantes naturais em alimentos, em substituição aos sintéticos. Neste trabalho a produção de pigmentos vermelhos foi avaliada (por meio de espectrofotometria de varredura em meio semi-sintético, empregando sete cepas de Monascus sp., através de cultivos conduzidos em incubador rotativo. As cepas isoladas no LEB/DEQ/EPUSP apresentaram média dos valores de absorbância dos pigmentos vermelhos extracelulares maior em relação às demais cepas (13,0 e 9,6 U, respectivamente, sendo que para as primeiras, a produção específica dos referidos pigmentos foi de 1,7 a 3,5 vezes maior que a produção específica dos pigmentos intracelulares.

  6. Concentration changes during venous occlusion of proteins with affinity for extracellular matrix in insulin-dependent diabetes mellitus A sign of vascular damage in patients with diabetic nephropathy?

    NARCIS (Netherlands)

    Myrup, B.; Rossing, P.; Jensen, T.; Gram, J.; Kluft, C.; Jespersen, J.

    1999-01-01

    Objective: To investigate protein concentration changes during venous occlusion of proteins with reported affinity for extracellular matrix (plasminogen activator inhibitor type 1, antithrombin III, fibronectin and von Willebrand factor) in comparison with proteins with no reported affinity (albumin

  7. Concentration changes during venous occlusion of proteins with affinity for extracellular matrix in insulin-dependent diabetes mellitus A sign of vascular damage in patients with diabetic nephropathy?

    NARCIS (Netherlands)

    Myrup, B.; Rossing, P.; Jensen, T.; Gram, J.; Kluft, C.; Jespersen, J.

    1999-01-01

    Objective: To investigate protein concentration changes during venous occlusion of proteins with reported affinity for extracellular matrix (plasminogen activator inhibitor type 1, antithrombin III, fibronectin and von Willebrand factor) in comparison with proteins with no reported affinity

  8. CALCIUM AND MAGNESIUM CONCENTRATION OF BREAST MILK IN RELATION WITH AGE AND PARITY OF NURSING WOMEN

    Directory of Open Access Journals (Sweden)

    Zofia Goc

    2012-08-01

    Full Text Available The aim of this study was determination of the concentration of calcium and magnesium in human milk (n=150 taken from nursing women who lived permanently in Malopolska district (South Poland. Milk samples were classified into groups taking into account women’ age and parity. According to the various age of the women milk samples were segregated into three groups: 20-25 years old, 26-31 years old and 32-37 years old. Included parity milk samples were spitted into two groups: the first group consisted of women who were primiparous (1 baby, the second group included women who were multiparous (≥2 babies. Milk samples were taken between the 7th and 14th day of the postpartum in each age group. The samples were taken by manual expression every morning. The analyses of metals were done by flame atomic absorption spectrophotometry (FAAS, after all samples had been collected. The mean concentration of cooper in milk taken from women of first age group (20-25 years old was 209.44±15.10 mg/L, in second group (26-31 years old was 238.65±13.34 mg/L and in the oldest group (32-37 years old was 261.44±17.16 mg/L. The mean concentration of magnesium in the same group of age was 42.12±3.793 mg/L, 47.51±2.728 mg/L and 45.43±3.840 mg/L, respectively. The mean concentration of calcium in milk taken from primiparous was 223.17±10.50mg/L, in multiparous was 266.37±16.20 mg/L. Whereas, the mean concentration of magnesium in transitional milk taken from the same group was 44.12±2.58 mg/L and 47.412±3.16 mg/L, respectively. Statistical analyses showed that there were statistically significant differences between calcium level in milk taken from the youngest group and the concentration of this metal in milk from the oldest group (p=0.032. Also, when comparing women’s parity, significant differences were found in the concentration of calcium (p=0.022. However, the differences in magnesium levels between tested groups were no statistically significant

  9. Calcium channel as a potential anticancer agent.

    Science.gov (United States)

    Kriazhev, L

    2009-11-01

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

  10. Basic properties of calcium phosphate cement containing different concentrations of citric acid solution

    Institute of Scientific and Technical Information of China (English)

    戴红莲; 闫玉华; 冯凌云; 李世普; 贺建华

    2002-01-01

    The properties of calcium phosphate cement consisting of α-tricalcium phosphate (α-TCP) and tetracalcium phosphate (TTCP) have been investigated by using a cement liquid that contained citric acid with concentration of 0.05 mol/L or higher. The relationship between the setting time of the system cement and the concentration of citric acid solution shows concave type curve. When solution concentration was 0.2 mol/L, the setting time was 8 min, which was the shortest. While the relationship between 24 h compressive strength of the cement and the citric acid concentration shows convex type curve. When solution concentration was 0.2 mol/L, the compressive strength was 39.0 MPa, which was the highest. Afterwards, the microstructure of the hardening product was observed by SEM, the effect of citric acid on the exothermic rate of hydrate reaction was studied by microcalorimeter, and the crushed specimens were subjected to X-ray diffraction. The results verified that the low citric acid concentration can accelerate the hydrate reaction rate of the α-TCP/TTCP system. However, the high citric acid concentration inhibited hydroxyapatite formation and retarded the rate of hydrate reaction of the α-TCP/TTCP cement.

  11. Tyramine biosynthesis in Enterococcus durans is transcriptionally regulated by the extracellular pH and tyrosine concentration.

    Science.gov (United States)

    Linares, Daniel M; Fernández, María; Martín, M Cruz; Alvarez, Miguel A

    2009-11-01

    The microbial decarboxylation of some amino acids leads to the undesirable presence of biogenic amines in foods. One of the most abundant and frequent biogenic amines found in fermented foods is tyramine, which is produced by the decarboxylation of tyrosine. In the present work, transcriptional analysis of tyramine biosynthesis in Enterococcus durans IPLA655, a strain isolated from cheese, was studied. The gene coding for the tyrosine decarboxylase (tdcA) and that coding for the tyrosine-tyramine antiporter (tyrP) form an operon transcribed from the promoter P(tdcA), the expression of which is regulated by the extracellular pH and tyrosine concentration. Quantification of gene expression during the log phase of growth showed high concentrations of tyrosine and acidic pH conditions to induce tdcA-tyrP polycistronic messenger transcription.

  12. Plants sensitivity on nickel under different conditions of iron or calcium concentration in the nutrient medium

    Directory of Open Access Journals (Sweden)

    Renata Matraszek

    2013-12-01

    Full Text Available The sensitivity of six vegetable plants on nickel at early stages of their growth was investigated by index of tolerance. Besides the possibility of nickel fitostabilization by additional application of iron or calcium was tested. The experiment was conducted on Petri dishes. Different concentrations of nickel (0; 0,03; 0,06mM Ni as nickel sulphate, iron (0,05; O,OlmM Fe as Fe2+ citrate and calcium (0,50; 0,75; lmM Ca as calcium carbonate were added. Taking into consideration the sensitivity, investigated vegetables can be ordered in the following way: Cucurbita pepo conv. giromontiina L.>Lactuca sativa L.>Sinapis alba L.>Spinacia oleracea L.=Zea mays var. saccharata Kcke.>Phaseolus vulgaris L. Positive, statistically significant effect ofnickel fitostabilization (0,03 or 0,06mM Ni on elongative growth by the iron application (0,10mM Fe was shown for Zea mays var. saccharata Kcke independently of Ni concentration in the nutrient medium as well as for Sinapis alba L. and Phaseolus vulgaris L. in 0,06mM Ni. Addition as much as 0,75mM Ca in the presence 0,03mM Ni had positive result on Sinapis alba L and Phaseolus vulgaris L. seedlings as well as on Zea mays var. saccharata Kcke and Lactuca sativa L. roots and Cucurbita pepo convar. giromontiina L. shoots. Addition of 0,75mM Ca in the presence 0,06mM Ni promoted elongative growth of Zea mays var. saccharata Kcke seedlings. Application lmM Ca resulted in the promotion of elongative growth of Zea mays var. saccharata Kcke. roots (0,03mM Ni as well as Spinacia oleracea L. roots (0,06mM Ni.

  13. Formation of calcium phosphates by vapour diffusion in highly concentrated ionic micro-droplets

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, M. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy); Universita del Piemonte Orientale, Dipartimento di Scienze Mediche, Via Solaroli 4, 28100 Novara (Italy); Delgado-Lopez, J.M.; Gomez-Morales, J.; Hernandez-Hernandez, M.A.; Rodriguez-Ruiz, I. [Laboratorio de Estudios Cristalograficos, IACT CSIC-UGR, Edificio Lopez Neyra, Avenida del Conocimiento, s/n 18100 Armilla (Spain); Roveri, N. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy)

    2011-08-15

    In this work we have used the sitting drop vapour diffusion technique, employing the ''crystallization mushroom '' to analyze the evolution of calcium phosphate crystallization in micro-droplets containing high initial concentrations of Ca{sup 2+} and HPO{sub 4}{sup 2-}. The decomposition of NH{sub 4}HCO{sub 3} solution produces vapours of NH{sub 3} and CO{sub 2} which diffuse through the droplets containing an aqueous solution of Ca(CH{sub 3}COO){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4}. The result is the increase of pH by means of the diffusion of NH{sub 3} gas and the doping of the calcium phosphate with CO{sub 3}{sup 2-} ions by means of the diffusion of CO{sub 2} gas. The pH of the crystallization process is monitored and the precipitates at different times are characterized by XRD, FTIR, TGA, SEM and TEM techniques. The slow increase of pH and the high concentration of Ca{sup 2+} and HPO{sub 4}{sup 2-} in the droplets induce the crystallization of three calcium phosphate phases: dicalcium phosphate dihydrate (DCPD, brushite), octacalcium phosphate (OCP) and carbonate-hydroxyapatite (HA). The amount of HA nanocrystals with needle-like morphology and dimensions of about 100 nm, closely resembling the inorganic phase of bones, gradually increases, with the precipitation time up to 7 days, whereas the amount of DCPD, growing along the b axis, increases up to 3 days. Then, DCDP crystals start to hydrolyze yielding OCP nanoribbons and HA nanocrystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Prostaglandin A1 inhibits increases in intracellular calcium concentration, TXA2 production and platelet activation

    Institute of Scientific and Technical Information of China (English)

    Yi ZHU; Zhen-lun GU; Zhong-qin LIANG; Hui-lin ZHANG; Zheng-hong QIN

    2006-01-01

    Aim: In our previous studies we found that cyclopentenane prostaglandin A1 (PGA1) had neuroprotective effects in a rodent ischemic model. In the present study we aimed to investigate the inhibitory effect of PGA1 on platelet function. Method: The rate of aggregation of human platelets was measured by using turbidimetry. The rate of adhesion of platelets to cultured endothelial cells was determined by using [3H]-adenine labeled platelets. 5-Hydroxytryptamine release from platelets was measured with O-phthaldialdehyde fluorospectrophotometry. The levels of TXB2, a stable metabolite of TXA2, were determined by radioimmunoassay. Alternations in platelet morphology were observed using an electron microscope, and the intraplatelet free calcium concentrations were measured with Fluo-3/AM FCM assay. Results: PGA1 significantly inhibited thrombin-collagen-and ADP-induced aggregation and adhesion of platelets. The morphological changes of platelets induced by thrombin were blocked by PGA1. PGA1 inhibited the release of 5-hydroxytyptamine from dense granules and the synthesis of TXA2. Conclusion: PGA1 inhibits the activation of platelets probably through blocking increases in intracellular calcium concentration and TXA2 synthesis.

  15. IFCC recommended reference method for the determination of the substance concentration of ionized calcium in undiluted serum, plasma or whole blood

    NARCIS (Netherlands)

    Burnett, RW; Christiansen, TF; Covington, AK; Fogh-Andersen, N; Kulpmann, WR; Lewenstam, A; Maas, AHJ; Muller-Plathe, O; Sachs, C; Siggaard-Andersen, O; VanKessel, AL; Zijlstra, WG

    2000-01-01

    A reference method is described for the determination of the substance concentration of ionized calcium in plasma by which ionized calcium (free or unbound) may be reliably determined on the basis of calibration with aqueous solutions with known concentration of ionized calcium. The composition of t

  16. High extracellular potassium ion concentration attenuates the blockade action of ketanserin on Kvl.3 channels expressed in xenopus oocytes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method was used to investigate the effect of KT and potassium ion on Kv1.3 potassium channels and explore the role of blocker KT in the alteration of channel kinetics contributing to the potassium ion imbalances. Methods Kvl.3 channels were expressed in xenopus oocytes, and currents were measured using the two-microelectrode voltage-clamp technique. Results KCI made a left shift of activation and an inactivation curve of Kv1.3 current and accelerated the activation and inactivation time constant. High extracellular [K+] attenuated the blockade effect of KT on Kv1.3 channels. In the presence of KT and KCI the activation and inactivation time constants were not influenced significantly no matter what was administered first. KT did not significantly inhibit Kv1.3 current induced by tetraethylammonium (TEA). Conclusions KT is a weak blocker of Kv1.3 channels at different concentrations of extracellular potassium and binds to the intracellular side of the channel pore. The inhibitor KT of ion channels is not fully effective in clinical use because of high [K+]o and other electrolyte disorders.

  17. Elevated extracellular calcium increases expression of bone morphogenetic protein-2 gene via a calcium channel and ERK pathway in human dental pulp cells

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Hiroyuki [Division of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Nemoto, Eiji, E-mail: e-nemoto@umin.ac.jp [Division of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan); Kanaya, Sousuke; Hamaji, Nozomu; Sato, Hisae; Shimauchi, Hidetoshi [Division of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, Sendai 980-8575 (Japan)

    2010-04-16

    Dental pulp cells, which have been shown to share phenotypical features with osteoblasts, are capable of differentiating into odontoblast-like cells and generating a dentin-like mineral structure. Elevated extracellular Ca{sup 2+}Ca{sub o}{sup 2+} has been implicated in osteogenesis by stimulating the proliferation and differentiation of osteoblasts; however, the role of Ca{sub o}{sup 2+} signaling in odontogenesis remains unclear. We found that elevated Ca{sub o}{sup 2+} increases bone morphogenetic protein (BMP)-2 gene expression in human dental pulp cells. The increase was modulated not only at a transcriptional level but also at a post-transcriptional level, because treatment with Ca{sup 2+} increased the stability of BMP-2 mRNA in the presence of actinomycin D, an inhibitor of transcription. A similar increase in BMP-2 mRNA level was observed in other human mesenchymal cells from oral tissue; periodontal ligament cells and gingival fibroblasts. However, the latter cells exhibited considerably lower expression of BMP-2 mRNA compared with dental pulp cells and periodontal ligament cells. The BMP-2 increase was markedly inhibited by pretreatment with an extracellular signal-regulated kinase (ERK) inhibitor, PD98059, and partially inhibited by the L-type Ca{sup 2+} channels inhibitor, nifedipine. However, pretreatment with nifedipine had no effect on ERK1/2 phosphorylation triggered by Ca{sup 2+}, suggesting that the Ca{sup 2+} influx from Ca{sup 2+} channels may operate independently of ERK signaling. Dental pulp cells do not express the transcript of Ca{sup 2+}-sensing receptors (CaSR) and only respond slightly to other cations such as Sr{sup 2+} and spermine, suggesting that dental pulp cells respond to Ca{sub o}{sup 2+} to increase BMP-2 mRNA expression in a manner different from CaSR and rather specific for Ca{sub o}{sup 2+} among cations.

  18. The response of a human bronchial epithelial cell line to histamine: Intracellular calcium changes and extracellular release of inflammatory mediators

    Energy Technology Data Exchange (ETDEWEB)

    Noah, T.L.; Paradiso, A.M.; Madden, M.C.; McKinnon, K.P.; Devlin, R.B. (Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill (United States))

    1991-11-01

    Epithelial cells are likely to modulate inflammation and tissue repair in the airways, but the factors responsible for these processes remain unclear. Because human airway epithelia are infrequently available for in vitro studies, transformed epithelial cell lines are of interest as models. The authors therefore investigated the response of an SV-40/adenovirus-transformed human bronchial epithelial cell line (BEAS-2B) to histamine, a mediator with relevance for airway diseases. The intracellular calcium response to histamine (10(-4) M) was measured, using Fura-2 and microspectrofluorimetry. Histamine induced a transient increase in intracellular calcium that originated from intracellular sources; this effect was inhibited by the H1 receptor antagonist diphenhydramine, suggesting that BEAS cells retain functioning histamine receptors. BEAS cells were grown to confluence on microporous, collagen-coated filters, allowing measurement of vectorial release of soluble mediators. Monolayers exposed to histamine for 30 min released interleukin-6 and fibronectin in the apical direction, in a dose-dependent manner. Little eicosanoid production was induced by histamine, either in the apical or the basolateral direction, although BEAS cells constitutively produced small amounts of prostaglandin E2 and 15-HETE. However, these cells formed large amounts of eicosanoids in response to ozone exposure as a positive control. Comparison of their data with published reports for human airway epithelia in primary culture suggests that the BEAS cell line is, in a number of respects, a relevant model for the study of airway epithelial responses to a variety of stimuli.

  19. Intracellular ionized calcium concentration in muscles from humans with malignant hyperthermia.

    Science.gov (United States)

    López, J R; Alamo, L; Caputo, C; Wikinski, J; Ledezma, D

    1985-06-01

    Ca2+ selective microelectrodes have been used to determine the free myoplasmic [Ca2+] in human skeletal muscle obtained from patients who had developed early signs associated with malignant hyperthermia (MH) during anesthesia. Intercostal muscle biopsies were performed under local anesthesia in four MH patients 15 days to 4 months after developing the MH crisis and in three control subjects. We used only microelectrodes that showed a Nernstian response between pCa3 and pCa7 (30.5 mV per decade at 37 degrees C). Membrane resting potential (V(m)) and calcium potential (V(Ca)) were obtained from superficial fibers. The free cytosolic [Ca2+] was 0.39 +/- 0.1 microM (mean +/- SEM, n = 18) in muscle fibers obtained from malignant hyperthermic patients, whereas in control subjects it was 0.11 +/- 0.02 microM (n = 10). These results suggest that this syndrome might be related to an abnormally high myoplasmic free resting calcium concentration, probably due to a defective function of the plasma membrane or the sarcoplasmic reticulum.

  20. Calcium montmorillonite clay in dairy feed reduces aflatoxin concentrations in milk without interfering with milk quality, composition or yield

    Science.gov (United States)

    This study was designed to determine if a calcium montmorillonite clay (Novasil Plus, NSP), can significantly reduce aflatoxin M1 (AFM1) concentrations in milk without affecting dry matter intake (DMI), milk yield, milk composition, vitamin A, or riboflavin concentrations. The study was designed us...

  1. Probing Intracellular Element Concentration Changes during Neutrophil Extracellular Trap Formation Using Synchrotron Radiation Based X-Ray Fluorescence

    Science.gov (United States)

    Niemiec, Maria J.; Laforce, Brecht; Garrevoet, Jan; Vergucht, Eva; De Rycke, Riet; Cloetens, Peter; Urban, Constantin F.; Vincze, Laszlo

    2016-01-01

    High pressure frozen (HPF), cryo-substituted microtome sections of 2 μm thickness containing human neutrophils (white blood cells) were analyzed using synchrotron radiation based X-ray fluorescence (SR nano-XRF) at a spatial resolution of 50 nm. Besides neutrophils from a control culture, we also analyzed neutrophils stimulated for 1–2 h with phorbol myristate acetate (PMA), a substance inducing the formation of so-called Neutrophil Extracellular Traps (or NETs), a defense system again pathogens possibly involving proteins with metal chelating properties. In order to gain insight in metal transport during this process, precise local evaluation of elemental content was performed reaching limits of detection (LODs) of 1 ppb. Mean weight fractions within entire neutrophils, their nuclei and cytoplasms were determined for the three main elements P, S and Cl, but also for the 12 following trace elements: K, Ca, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Sr and Pb. Statistical analysis, including linear regression provided objective analysis and a measure for concentration changes. The nearly linear Ca and Cl concentration changes in neutrophils could be explained by already known phenomena such as the induction of Ca channels and the uptake of Cl under activation of NET forming neutrophils. Linear concentration changes were also found for P, S, K, Mn, Fe, Co and Se. The observed linear concentration increase for Mn could be related to scavenging of this metal from the pathogen by means of the neutrophil protein calprotectin, whereas the concentration increase of Se may be related to its antioxidant function protecting neutrophils from the reactive oxygen species they produce against pathogens. We emphasize synchrotron radiation based nanoscopic X-ray fluorescence as an enabling analytical technique to study changing (trace) element concentrations throughout cellular processes, provided accurate sample preparation and data-analysis. PMID:27812122

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

    Directory of Open Access Journals (Sweden)

    Renshan Sun

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

  3. Mechanism by which an elevation of extracellular glucide concentration induces pigment aggregation in medaka melanophores.

    Science.gov (United States)

    Fujii, Ryozo; Goda, Makoto; Oshima, Noriko

    2002-09-15

    An increase in glucide concentration induces pigment aggregation in melanophores in the skin on scales isolated from the medaka, Oryzias latipes. In this study, hexoses (including the common D-isomers of glucose, galactose, fructose, and mannitol) were examined. Denervated melanophores were refractory to such stimuli. An alpha-adrenolytic agent, phentolamine, effectively blocked the responses of normally innervated melanophores. The pigment-aggregating action of glucide was inhibited by withdrawal of Ca(2+) and Mg(2+) ions from the medium. A specific blocker of voltage-dependent N-type Ca(2+) channels, the omega-conotoxin GVIA, also inhibited the glucide action. The conclusion derived is that an elevation of glucide levels acts to open Ca(2+) channels of presynaptic membranes of sympathetic postganglionic fibers, and the consequently released adrenergic transmitter acts on the effector cells to induce the aggregation of their pigmentary organelles. Copyright 2002 Wiley-Liss, Inc.

  4. The final phases of calcium and magnesium phosphates precipitated from solutions of high to medium concentration

    Science.gov (United States)

    Abbona, Francesco; Lundager Madsen, Hans Erik; Boistelle, Roland

    1988-07-01

    The phases of calcium and magnesium phosphates, which are obtained by evolution at 25°C of the first precipitates in their mother solutions, are described in terms of pH and composition of solutions. The initial conditions were: 0.050M ≤ [P] ≤ 0.500M; [P] = [Ca] + [Mg]; 0 ≤ [Mg]/[Ca] ≤ 1. The most abundant final phases are brushite, CaHPO 4·2H 2O; monetite, CaHPO 4; newberyite, MgHPO 4·3H 2O and struvite, MgNH 4PO 4·6H 2O. At low concentration whitlockite, Ca 9MgH(PO 4) 7, occurs with the amorphous phase previously precipitated, Ca 3(PO 4) 2·nH 2O. The conditions for stability are discussed and the changes observed are interpreted.

  5. Blood calcium and phosphorus concentrations in cows with left displaced abomasum

    Directory of Open Access Journals (Sweden)

    Šamanc Horea

    2009-01-01

    Full Text Available Abomasal displacement is one of the most important disorders of the digestive tract in high-yield dairy cows. The etiology and pathogenesis of its occurrence has not been fully clarified to this day. The work examines calcaemia and phosphataemia in cows during the antepartal and postpartal periods and their connection with the incidence of abomasal displacement. The experiment covered 30 cows in advanced stages of gravidity. Blood samples were taken two weeks before expected parturition and two weeks after calving. In all blood samples (taken antepartal and postpartal, concentrations of calcium and an organic phosphorus were determined using a commercial test package (Bio-Merieux. Following parturition, left displacement of the abomasums was established in seven (23.33 % of the 30 cows covered by the experiment (experimental group. The remaining 23 cows in the experiment were clinically healthy, they were placed in a group and represented control animals. The average value of calcaemia for the control group of cows during the antepartal period was 2.72±0.25 mmol/l, and of phosphataemia 2.04±0.25 mmol/l. In the same cows postpartum, average calcaemia values were 2.46±0.22 mmol/l and phosphataemia 1.85±0.29 mmol/l. The average antepartal value for calcaemia in the experimental group of cows was 2.51±0.25 mmol/l, and for phosphataemia 1.73± 0.22 mmol/l. The average values for this group of cows postpartally was 2.13±0.31 mmol/l for calcaemia and 1.43±0.24 mmol/l for phosphataemia. The differences between the concentration values for calcium and phosphorus obtained postpartally between the experimental and control groups were statistically significant. .

  6. Cytosolic Calcium Concentration Changes in Neuronal Cells Under Clinorotation and in Parabolic Flight Missions

    Science.gov (United States)

    Hauslage, Jens; Abbrecht, Medea; Hanke, Lars; Hemmersbach, Ruth; Koch, Claudia; Hanke, Wolfgang; Kohn, Florian P. M.

    2016-12-01

    All life on earth has been established under conditions of stable gravity of 1g. Nevertheless, in numerous experiments the direct gravity dependence of biological processes has been shown on all levels of organization, from single molecules to humans. To study the effects especially of microgravity on biological systems, a variety of platforms are available, from drop towers to the ISS. Due to the costs of these platforms and their limited availability, as an alternative, numerous simulators have been developed for so called "simulated" microgravity. A classical systems is a clinostat, basically rotating a sample around one axis, and by integration of the gravity vector for 360° arguing that thus the effects of gravity are depleted. Indeed, a variety of studies has shown that taking out the direction of gravity from a biological system often results in consequences similar to the exposure of the system to real microgravity. Nevertheless, the opposite has been shown, too, and as a consequence the relevance of clinostats in microgravity research is still under discussion. To get some more insight into this problem we have constructed a small fluorescence clinostat and have studied the effects of clinorotation on the cytosolic calcium concentration of neuroglioma cells. The results have been compared to experiments with identical cells in real microgravity, utilizing parabolic flight missions. Our results show that in case of a cell suspension used in a small florescence clinostat within a tube diameter of 2mm, the effects of clinorotation are comparable to those under real microgravity, both showing a significant increase in intracellular calcium concentration.

  7. Partial calcium depletion during membrane filtration affects gelation of reconstituted milk protein concentrates.

    Science.gov (United States)

    Eshpari, H; Jimenez-Flores, R; Tong, P S; Corredig, M

    2015-12-01

    Milk protein concentrate powders (MPC) with improved rehydration properties are often manufactured using processing steps, such as acidification and high-pressure processing, and with addition of other ingredients, such as sodium chloride, during their production. These steps are known to increase the amount of serum caseins or modify the mineral equilibrium, hence improving solubility of the retentates. The processing functionality of the micelles may be affected. The aim of this study was to investigate the effects of partial acidification by adding glucono-δ-lactone (GDL) to skim milk during membrane filtration on the structural changes of the casein micelles by observing their chymosin-induced coagulation behavior, as such coagulation is affected by both the supramolecular structure of the caseins and calcium equilibrium. Milk protein concentrates were prepared by preacidification with GDL to pH 6 using ultrafiltration (UF) and diafiltration (DF) followed by spray-drying. Reconstituted UF and DF samples (3.2% protein) treated with GDL showed significantly increased amounts of soluble calcium and nonsedimentable caseins compared with their respective controls, as measured by ion chromatography and sodium dodecyl sulfate-PAGE electrophoresis, respectively. The primary phase of chymosin-induced gelation was not significantly different between treatments as measured by the amount of caseino-macropeptide released. The rheological properties of the reconstituted MPC powders were determined immediately after addition of chymosin, both before and after dialysis against skim milk, to ensure similar serum composition for all samples. Reconstituted samples before dialysis showed no gelation (defined as tan δ=1), and after re-equilibration only control UF and DF samples showed gelation. The gelation properties of reconstituted MPC powders were negatively affected by the presence of soluble casein, and positively affected by the amount of both soluble and insoluble

  8. Plasma and synovial fluid concentrations of calcium pentosan polysulphate achieved in the horse following intramuscular injection.

    Science.gov (United States)

    Fuller, C J; Ghosh, P; Barr, A R S

    2002-01-01

    Results from in vitro studies have indicated that calcium pentosan polysulphate (CaPPS) may be of therapeutic value in osteoarthritis (OA) in the horse. However, no controlled clinical trials using this drug in equine OA have yet been reported. If CaPPS is to be developed for such use, the relationship between the proposed i.m. dose of CaPPS to be used and the concentrations of drug attained in plasma and synovial fluid of the target joint should first be established. An investigation was undertaken to determine these concentrations after a single 2 mg/kg i.m. injection of CaPPS. Blood and synovial fluid samples were taken from 6 healthy, sound horses following i.m. CaPPS administration. Concentrations of CaPPS measured in the synovial fluid were, on the basis of published studies, sufficient to elicit a potential therapeutic effect on synoviocyte metabolism, and possibly also to stimulate proteoglycan synthesis and reduce matrix metalloproteinase activities in articular cartilage. It would therefore seem justified to investigate further the therapeutic effect of CaPPS in OA in the horse.

  9. Spasmolytic effect of Petroselinum crispum (Parsley) on rat's ileum at different calcium chloride concentrations.

    Science.gov (United States)

    Moazedi, A A; Mirzaie, D N; Seyyednejad, S M; Zadkarami, M R; Amirzargar, A

    2007-11-15

    Traditional herbal medicines such as Petroselinum crispum (Parsley) have been used for treatment of intestinal disorders in Iran. To date no pharmacological evidence for their effectiveness has been reported. The aim of this study was to examine the relaxant effect of hydroalcoholic extract of Petroselinum crispum on isolated adult male Wistar rat's ileum contraction by KCl 60 (mM). The extract was prepared from parsley seed with 80% ethanol. A portion of ileum was removed and placed in an organ bath containing Tyrode solution (37 degrees C, pH = 7.4) bubbled with air. From a resting tension of 1 g, isotonic Transducer and Harvard Universal Oscillograph were used for recording contraction of ileum after administration of 60 mM KCl. Various concentration of extract were added to the bath. This experiment showed that, the extract in a dose-dependent manner decreased the induced-KCl ileums contraction (n = 7, p < 0.001). Also adding extract before influence of KCl, cause reduced effect of KCl (n = 7, p < 0.001). In addition, the Tyrode solution without CaCl2 and high concentration of K+, various concentration of extract significantly (n = 7, p < 0.001) decreased the CaCl2-induced contraction. Therefore, it seems that the relaxation effect of extract alcoholic parsley seed on the contraction of ileum is performed by blocking of voltage-gated calcium channels.

  10. Activity of the TonEBP/OREBP transactivation domain varies directly with extracellular NaCl concentration.

    Science.gov (United States)

    Ferraris, Joan D; Williams, Chester K; Persaud, Prita; Zhang, Zheng; Chen, Ye; Burg, Maurice B

    2002-01-22

    Hypertonicity-induced binding of the transcription factor TonEBP/OREBP to its cognate DNA element, ORE/TonE, is associated with increased transcription of several osmotically regulated genes. Previously, it was found that hypertonicity rapidly causes nuclear translocation and phosphorylation of TonEBP/OREBP and, more slowly, increases TonEBP/OREBP abundance. Also, the C terminus of TonEBP/OREBP was found to contain a transactivation domain (TAD). We have now tested for tonicity dependence of the TAD activity of the 983 C-terminal amino acids of TonEBP/OREBP. HepG2 cells were cotransfected with a reporter construct and one of several TAD expression vector constructs. The reporter construct contained GAL4 DNA binding elements, a minimal promoter, and the Photinus luciferase gene. TAD expression vectors generate chimeras comprised of the GAL4 DNA binding domain fused to (i) the 983 C-terminal amino acids of TonEBP/OREBP, (ii) 17 glutamine residues, (iii) the TAD of c-Jun, or (iv) no TAD. All TAD-containing chimeras were functional at normal extracellular osmolality (300 mosmol/kg), but the activity only of the chimera containing the 983 C-terminal amino acids of TonEBP/OREBP varied with extracellular NaCl concentration, decreasing by >80% at 200 mosmol/kg and increasing 8-fold at 500 mosmol/kg. The chimera containing the 983 C-terminal amino acids of TonEBP/OREBP was constitutively localized to the nucleus and showed tonicity-dependent posttranslational modification consistent with phosphorylation. The activity at 500 mosmol/kg was reduced by herbimycin, a tyrosine kinase inhibitor and by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, a protein kinase CK2 inhibitor. Thus, the 983 C-terminal amino acids of TonEBP/OREBP contain a TAD that is regulated osmotically, apparently by tonicity-dependent phosphorylation.

  11. Calcium, magnesium, and phosphorus metabolism, and parathyroid-calcitonin function during prolonged exposure to elevated CO2 concentrations on submarines.

    Science.gov (United States)

    Messier, A A; Heyder, E; Braithwaite, W R; McCluggage, C; Peck, A; Schaefer, K E

    1979-01-01

    Studies of calcium and phosphorus metabolism and acid-base balance were carried out on three Fleet Ballistic Missile (FBM) submarines during prolonged exposure to elevated concentrations of CO2. The average CO2 concentration in the submarine atmosphere during patrols ranged from 0.85% to 1% CO2. In the three studies, in which 9--15 subjects participated, the urinary excretion of calcium and phosphate fell during the first three weeks to a level commensurate with a decrease in plasma calcium and increase in phosphorus. In the fourth week of one patrol, a marked increase was found in urinary calcium excretion, associated with a rise in blood PCO2 and bicarbonate. Urinary calcium excretion decreased again during the 5th to 8th week, with a secondary decrease in blood pH and plasma calcium. During the third patrol, the time course of acid-base changes corresponded well with that found during the second patrol. There was a trend toward an increase in plasma calcium between the fourth and fifth week commensurate with the transient rise in pH and bicarbonate. Plasma parathyroid and calcitonin hormone activities were measured in two patrols and no significant changes were found. Hydroxyproline excretion decreased in the three-week study and remained unchanged in the second patrol, which lasted 57 days. It is suggested that during prolonged exposure to low levels of CO2 (up to 1% CO2), calcium metabolism is controlled by the uptake and release of CO2 in the bones. The resulting phases in bone buffering, rather than renal regulation, determine acid-base balance.

  12. Extracellular calcium is involved in egg yolk-induced head-to-head agglutination of bull sperm.

    Science.gov (United States)

    Yang, D H; McMillan, A G; Standley, N T; Shannon, P; Xu, Z Z

    2012-10-15

    Head-to-head agglutination of bull sperm occurs when semen is highly diluted in an egg yolk-citrate diluent without streptomycin. The objectives were to investigate causes of sperm agglutination and the underlying mechanism. Aliquots of bull semen were diluted in a base diluent (BD) supplemented with various test components and the percentage of agglutinated sperm (% AggSp) was quantified at 1, 5, 24, 48, and 72 h of incubation. When sperm were incubated at 22 °C, no agglutination was observed in BD for up to 72 h, whereas the % AggSp was 5.0, 41.7, 72.2, 91.1, and 92.8% in BD + 5% egg yolk (BD + EY) at 1, 5, 24, 48 and 72 h, respectively. However, no sperm agglutination was observed in BD + EY if incubation temperature was 37 °C. Addition of 5 or 10 mM ethylenebis (oxyethyleneni-trilo) tetra-acetic acid to BD + EY reduced the % AggSp from 95% to sperm agglutination in the absence of egg yolk, implicating calcium and other factors in egg yolk. Addition of the citrate-soluble fraction (CSF) of egg yolk to BD induced sperm agglutination similar to whole egg yolk, whereas water- and saline-soluble fractions of egg yolk were ineffective. The sperm-agglutinating efficacy of CSF (the % AggSp = 95% at 72 h) was reduced by dialysis (20%; P sperm agglutination, whereas addition of 2 mM of a cAMP analogue, dbcAMP, to a nonagglutinating diluent failed to induce sperm agglutination. Agglutination status had no effect on sperm plasma membrane/acrosome status and mitochondrial membrane potential. In conclusion, calcium and other component(s) in the CSF of egg yolk induced head-to-head agglutination of bull sperm in a time- and temperature-dependent manner. Although the mechanism of agglutination was not determined, the cAMP- protein kinase A signaling pathway was not involved.

  13. Modulation of carbachol-stimulated inositol phospholipid breakdown in rat cerebral cortical miniprisms at excitatory amino acids and by BAY K-8644 is dependent upon the assay calcium and potassium concentrations used

    Energy Technology Data Exchange (ETDEWEB)

    Tiger, G. (Univ. of Umea (Sweden)); Fowler, C.J. (Astra Research Centre, Soedertalje (Sweden))

    1991-01-01

    The calcium and potassium ion dependency of the inositol phospholipid breakdown response to stimulatory agents has been investigated in rat cerebral cortical miniprisms. The calcium channel agonist BAY K-8644 potentiated the response to carbachol at 6 mM K{sup +} when Ca{sup 2+}-free, but not when 2.52 mM Ca{sup 2+} assay buffer was used. In Ca{sup 2+}-free buffer, verapamil inhibited the response to carbachol at both 6 and 18 mM K{sup +} but higher concentrations were needed when 2.52 mM Ca{sup 2+} was used. At these higher concentrations, however, verapamil inhibited the binding of 2 nM ({sup 3}H)pirenzepine to muscarinic recognition sites. N-Methyl-D-Aspartate (NMDA) significantly reduced the basal phosphoinositide breakdown rate at 18 mM K{sup +} at 1.3 mM Ca{sup 2+}, but was without effect on the basal rate at other K{sup +} and Ca{sup 2+} concentrations. In the presence of NMDA or quisqualate, the responses to carbachol were reduced, the degree of reduction showing a complex dependency upon the assay K{sup +} and Ca{sup 2+} concentrations used. These results indicate that the inositol phospholipid breakdown response to carbachol in cerebral cortical miniprisms can be modulated in a manner dependent upon the extracellular calcium and potassium concentrations used.

  14. The influence of statins on the free intracellular calcium concentration in human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Figulla Hans R

    2004-05-01

    Full Text Available Abstract Background Statins are cholesterol-lowering drugs that are widely used to reduce the risk of cardiac infarction. Their beneficial clinical effects, however, are not restricted to their influence on cholesterol production. As several studies have shown that they have a potency of relaxing blood vessels. Methods We measured the effects of statins on the intracellular free calcium concentration ([Ca2+]i in human umbilical vein endothelial cells (HUVEC after acute application and 24-h-preincubation of statins. Results Incubation of the cells for 24 h with cerivastatin or fluvastatin significantly increased the resting [Ca2+]i. For cerivastatin this effect manifested at a concentration of 1 μM. Increase of resting [Ca2+]i in the presence of cerivastatin also occurred when the nitric oxide synthase was inhibited. Transient Ca2+ release induced by histamine was not affected. Conclusions The increase of resting [Ca2+]i after incubation with cerivastatin or fluvastatin may provide an explanation for the direct effects of statins on the endothelial-dependent vasodilatation and restoration of endothelial activity in vivo.

  15. Sub-inhibitory tigecycline concentrations induce extracellular matrix binding protein Embp dependent Staphylococcus epidermidis biofilm formation and immune evasion.

    Science.gov (United States)

    Weiser, Julian; Henke, Hanae A; Hector, Nina; Both, Anna; Christner, Martin; Büttner, Henning; Kaplan, Jeffery B; Rohde, Holger

    2016-09-01

    Biofilm-associated Staphylococcus epidermidis implant infections are notoriously reluctant to antibiotic treatment. Here we studied the effect of sub-inhibitory concentrations of penicillin, oxacillin, vancomycin, daptomycin, linezolid and tigecycline on S. epidermidis 1585 biofilm formation, expression of extracellular matrix binding protein (Embp) and potential implications for S. epidermidis - macrophage interactions. Penicillin, vancomycin, daptomycin, and linezolid had no biofilm augmenting effect at any of the concentrations tested. In contrast, at sub-inhibitory concentrations tigecycline and oxacillin exhibited significant biofilm inducing activity. In S. epidermidis 1585, SarA is a negative regulator of giant 1 MDa Embp, and down regulation of sarA induces Embp-dependent assembly of a multi-layered biofilm architecture. Dot blot immune assays, confocal laser scanning microscopy, and qPCR showed that under biofilm inducing conditions, tigecycline augmented embp expression compared to the control grown without antibiotics. Conversely, expression of regulator sarA was suppressed, suggesting that tigecycline exerts its effects on embp expression through SarA. Tigecycline failed to induce biofilm formation in embp transposon mutant 1585-M135, proving that under these conditions Embp up-regulation is necessary for biofilm accumulation. As a functional consequence, tigecycline induced biofilm formation significantly impaired the up-take of S. epidermidis by mouse macrophage-like cell line J774A.1. Our data provide novel evidence for the molecular basis of antibiotic induced biofilm formation, a phenotype associated with inherently increased antimicrobial tolerance. While this could explain failure of antimicrobial therapies, persistence of S. epidermidis infections in the presence of sub-inhibitory antimicrobials is additionally propelled by biofilm-related impairment of macrophage-mediated pathogen eradication.

  16. Effect of Fermentation Time and Calcium Nitrate Concentration on Enzyme Glucoamylase Production of Gliocladium KE Using Sago Hampas Solid Substrate

    Directory of Open Access Journals (Sweden)

    Risa Meutia Fiana

    2013-01-01

    Full Text Available This research aims to obtain the appropriate fermentation time and suitable concentration of calcium nitrate (Ca (NO3 2 which is suitable with minerals solution used for sago hampas as a solid substrate to produce optimal activity of glucoamylase. This study was conducted in two stages. The first stage is to apprehend the fermentation time of Gliocladium KE fungal on solid substrates to produce optimal glucoamylase enzyme activity. Fermentation was conducted in 6 days, which each day is measured enzyme activity of glucoamylse and counted the number of spores of Gliocladium KE. The second stage is to get the optimal concentration of calcium nitrate was added to the mineral solution on a solid substrate of sago hampas to produce the highest glucoamylase. The concentration of calcium nitrat used was 2.57 g, 3.57 g and 4..57 g. The results showed that the fermentation for 4 days produced the highest glucoamylase enzyme activity of 24.22 units / mL by the number of spores 2.7 x 10 8 spores / mL. The concentration of calcium nitrat on 3:57 g with fermentation for 4 days resulted in the highest enzyme glucoamylase.

  17. Influence of calcium chelators on concentrated micellar casein solutions : from micellar structure to viscosity and heat stability

    NARCIS (Netherlands)

    Kort, de E.J.P.

    2012-01-01

    In practice it is challenging to prepare a concentrated medical product with high heat stability
    and low viscosity. Calcium chelators are often added to dairy products to improve heat stability,
    but this may increase viscosity through interactions with the casein proteins. The aim of

  18. Influence of calcium chelators on concentrated micellar casein solutions : from micellar structure to viscosity and heat stability

    NARCIS (Netherlands)

    Kort, de E.J.P.

    2012-01-01

    In practice it is challenging to prepare a concentrated medical product with high heat stability
    and low viscosity. Calcium chelators are often added to dairy products to improve heat stability,
    but this may increase viscosity through interactions with the casein proteins. The aim of thi

  19. Development of a Rat Plasma and Brain Extracellular Fluid Pharmacokinetic Model for Bupropion and Hydroxybupropion Based on Microdialysis Sampling, and Application to Predict Human Brain Concentrations.

    Science.gov (United States)

    Cremers, Thomas I F H; Flik, Gunnar; Folgering, Joost H A; Rollema, Hans; Stratford, Robert E

    2016-05-01

    Administration of bupropion [(±)-2-(tert-butylamino)-1-(3-chlorophenyl)propan-1-one] and its preformed active metabolite, hydroxybupropion [(±)-1-(3-chlorophenyl)-2-[(1-hydroxy-2-methyl-2-propanyl)amino]-1-propanone], to rats with measurement of unbound concentrations by quantitative microdialysis sampling of plasma and brain extracellular fluid was used to develop a compartmental pharmacokinetics model to describe the blood-brain barrier transport of both substances. The population model revealed rapid equilibration of both entities across the blood-brain barrier, with resultant steady-state brain extracellular fluid/plasma unbound concentration ratio estimates of 1.9 and 1.7 for bupropion and hydroxybupropion, respectively, which is thus indicative of a net uptake asymmetry. An overshoot of the brain extracellular fluid/plasma unbound concentration ratio at early time points was observed with bupropion; this was modeled as a time-dependent uptake clearance of the drug across the blood-brain barrier. Translation of the model was used to predict bupropion and hydroxybupropion exposure in human brain extracellular fluid after twice-daily administration of 150 mg bupropion. Predicted concentrations indicate that preferential inhibition of the dopamine and norepinephrine transporters by the metabolite, with little to no contribution by bupropion, would be expected at this therapeutic dose. Therefore, these results extend nuclear imaging studies on dopamine transporter occupancy and suggest that inhibition of both transporters contributes significantly to bupropion's therapeutic efficacy.

  20. Effect of L (+) ascorbic acid and monosodium glutamate concentration on the morphology of calcium carbonate

    Science.gov (United States)

    Saraya, Mohamed El-shahte Ismaiel

    2015-11-01

    In this study, monosodium glutamate and ascorbic acid were used as crystal and growth modifiers to control the crystallization of CaCO3. Calcium carbonate prepared by reacting a mixed solution of Na2CO3 with CaCl2 at ambient temperature, (25 °C), constant Ca++/ CO3- - molar ratio and pH with stirring. The polymorph and morphology of the crystals were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicate that rhombohedral calcite was only formed in water without organic additives, and both calcite and spherical vaterite with various morphologies were produced in the presence of monosodium glutamate. The content of vaterite increased as the monosodium glutamate increased. In addition, spherical vaterite was obtained in the presence of different concentrations of ascorbic acid. The spherical vaterite posses an aggregate shape composed of nano-particles, ranging from 30 to 50 nm as demonstrated by the SEM and TEM analyses. Therefore, the ascorbic stabilizes vaterite and result in nano-particles compared to monosodium glutamate.

  1. Arginine vasopressin increases cellular free calcium concentration and adenosine 3',5'-monophosphate production in rat renal papillary collecting tubule cells in culture

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, S.; Okada, K.; Saito, T.

    1988-09-01

    The role of calcium (Ca) in the cellular action of arginine vasopressin (AVP) was examined in rat renal papillary collecting tubule cells in culture. AVP increased both the cellular free Ca concentration ((Ca2+)i) using fura-2, and cAMP production in a dose-dependent manner. AVP-induced cellular Ca mobilization was totally blocked by the antagonist to the antidiuretic action of AVP, and somewhat weakened by the antagonist to the vascular action of AVP. 1-Deamino-8-D-AVP (dDAVP). an antidiuretic analog of AVP, also increased (Ca2+) significantly. Cellular Ca mobilization was not obtained with cAMP, forskolin (a diterpene activator of adenylate cyclase), or phorbol-12-myristate-13-acetate. The early phase of (Ca2+)i depended on the intracellular Ca pool, since an AVP-induced rise in (Ca2+)i was obtained in cells pretreated with Ca-free medium containing 1 mM EGTA, verapamil, or cobalt, which blocked cellular Ca uptake. Also, AVP increased /sup 45/Ca2+ influx during the initial 10 min, which initiated the sustained phase of cellular Ca mobilization. However, cellular cAMP production induced by AVP during the 10-min observation period was diminished in the cells pretreated with Ca-free medium, verapamil, or cobalt, but was still significantly higher than the basal level. This was also diminished by a high Ca concentration in medium. These results indicate that 1) AVP concomitantly regulates cellular free Ca as well as its second messenger cAMP production; 2) AVP-induced elevation of cellular free Ca is dependent on both the cellular Ca pool and extracellular Ca; and 3) there is an optimal level of extracellular Ca to modulate the AVP action in renal papillary collecting tubule cells.

  2. Artificial activation of bovine and equine oocytes with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine in low or high calcium concentrations.

    Science.gov (United States)

    Fernandes, Claudia Barbosa; Devito, Liani Gasparini; Martins, Lilian Rigatto; Blanco, Ieda Dala Pria; de Lima Neto, João Ferreria; Tsuribe, Patricia Myakawa; Gonçalves, Camila Gabriela Pereria; da Cruz Landim-Alvarenga, Fernanda

    2014-08-01

    Knowledge on parthenogenetic activation of oocytes is important to improve the efficiency of nuclear transfer (NT) and intracytoplasmic sperm injection (ICSI) because artificial activation of oocyte (AOA) is an essential step to achieve embryo production. Although different procedures for AOA have been established, the efficiency of in vitro production of embryos remains low, especially in equines and Bos taurus bovines. In an attempt to improve the techniques of NT and ICSI in bovine and equine species, we tested different combinations of drugs that had different mechanisms of action for the parthenogenetic activation of oocytes in these animals. The oocytes were collected, in vitro matured for 24 to 30 h and activated artificially, in the presence of low or high concentrations of calcium, with combinations of calcium ionophore (ionomycin) with cycloheximide, roscovitine, strontium, or 6-dimethylaminopurine (6-DMAP). For assessment of activation rates, oocytes were stained with Hoechst 33342 and observed under an inverted microscope. We showed that all combinations of drugs were equally efficient in activating bovine oocytes, with the best results obtained when high concentrations of calcium were adopted. For equine oocytes, high concentrations of calcium were not beneficial for the parthenogenetic activation and the combination of ionomycin with either 6-DMAP or roscovitine was effective in inducing artificial activation of oocytes. We believe that our preliminary findings provide some clues for the development of a better AOA protocol to be used with these species.

  3. Effect of insoluble calcium concentration on endogenous syneresis rate in rennet-coagulated bovine milk.

    Science.gov (United States)

    Choi, J; Horne, D S; Lucey, J A

    2015-09-01

    values of gels (indicating greater mobility), probably due to the loss of insoluble calcium phosphate crosslinking within micelles, which was significantly negatively correlated (r≥0.81) with the rate constant for endogenous syneresis. In the EDTA trial, with an increase in the EDTA concentration no maximum was observed in the rate constants related to proteolysis of κ-casein hairs or crosslinking of these activated sites. The rate constant for endogenous syneresis decreased at higher EDTA levels. The different rheological/modeling behavior in the EDTA trials was likely due to the very significant inhibition of rennet gelation induced by the use of EDTA, which also resulted in extremely long reaction times. Our modified Carlson model fit our experimental pH trial data very well, which indicates that the rennet gel system has the potential to synerese from the start; indeed this ability is an innate property of the casein micelle. Endogenous syneresis was enhanced by the loss of insoluble calcium phosphate crosslinking within casein micelles as this increased bond mobility within rennet gels.

  4. Meta-analysis of genome-wide association studies identifies six new Loci for serum calcium concentrations.

    Directory of Open Access Journals (Sweden)

    Conall M O'Seaghdha

    Full Text Available Calcium is vital to the normal functioning of multiple organ systems and its serum concentration is tightly regulated. Apart from CASR, the genes associated with serum calcium are largely unknown. We conducted a genome-wide association meta-analysis of 39,400 individuals from 17 population-based cohorts and investigated the 14 most strongly associated loci in ≤ 21,679 additional individuals. Seven loci (six new regions in association with serum calcium were identified and replicated. Rs1570669 near CYP24A1 (P = 9.1E-12, rs10491003 upstream of GATA3 (P = 4.8E-09 and rs7481584 in CARS (P = 1.2E-10 implicate regions involved in Mendelian calcemic disorders: Rs1550532 in DGKD (P = 8.2E-11, also associated with bone density, and rs7336933 near DGKH/KIAA0564 (P = 9.1E-10 are near genes that encode distinct isoforms of diacylglycerol kinase. Rs780094 is in GCKR. We characterized the expression of these genes in gut, kidney, and bone, and demonstrate modulation of gene expression in bone in response to dietary calcium in mice. Our results shed new light on the genetics of calcium homeostasis.

  5. Plasma concentrations of extracellular matrix protein fibulin-1 are related to cardiovascular risk markers in chronic kidney disease and diabetes

    Directory of Open Access Journals (Sweden)

    Scholze Alexandra

    2013-01-01

    Full Text Available Abstract Background Fibulin-1 is one of a few extracellular matrix proteins present in blood in high concentrations. We aimed to define the relationship between plasma fibulin-1 levels and risk markers of cardiovascular disease. Methods Plasma fibulin-1 was determined in subjects with chronic kidney disease (n = 32; median age 62.5, inter-quartile range 51 – 73 years and 60 age-matched control subjects. Among kidney disease patients serological biomarkers related to cardiovascular disease (fibrinogen, interleukin 6, C-reactive protein were measured. Arterial applanation tonometry was used to determine central hemodynamic and arterial stiffness indices. Results We observed a positive correlation of fibulin-1 levels with age (r = 0.38; p = 0.033, glycated hemoglobin (r = 0.80; p = 0.003, creatinine (r = 0.35; p = 0.045, and fibrinogen (r = 0.39; p = 0.027. Glomerular filtration rate and fibulin-1 were inversely correlated (r = −0.57; p = 0.022. There was a positive correlation between fibulin-1 and central pulse pressure (r = 0.44; p = 0.011 and central augmentation pressure (r = 0.55; p = 0.001. In a multivariable regression model, diabetes, creatinine, fibrinogen and central augmentation pressure were independent predictors of plasma fibulin-1. Conclusion Increased plasma fibulin-1 levels were associated with diabetes and impaired kidney function. Furthermore, fibulin-1 levels were associated with hemodynamic cardiovascular risk markers. Fibulin-1 is a candidate in the pathogenesis of cardiovascular disease observed in chronic kidney disease and diabetes.

  6. Cinacalcet Reduces Serum Calcium Concentrations in Patients with Intractable Primary Hyperparathyroidism

    Science.gov (United States)

    Marcocci, Claudio; Chanson, Philippe; Shoback, Dolores; Bilezikian, John; Fernandez-Cruz, Laureano; Orgiazzi, Jacques; Henzen, Christoph; Cheng, Sunfa; Sterling, Lulu Ren; Lu, John; Peacock, Munro

    2009-01-01

    Context: Patients with persistent primary hyperparathyroidism (PHPT) after parathyroidectomy or with contraindications to parathyroidectomy often require chronic treatment for hypercalcemia. Objective: The objective of the study was to assess the ability of the calcimimetic, cinacalcet, to reduce serum calcium in patients with intractable PHPT. Design: This was an open-label, single-arm study comprising a titration phase of variable duration (2–16 wk) and a maintenance phase of up to 136 wk. Setting: The study was conducted at 23 centers in Europe, the United States, and Canada. Patients: The study included 17 patients with intractable PHPT and serum calcium greater than 12.5 mg/dl (3.1 mmol/liter). Intervention: During the titration phase, cinacalcet dosages were titrated every 2 wk (30 mg twice daily to 90 mg four times daily) for 16 wk until serum calcium was 10 mg/dl or less (2.5 mmol/liter). If serum calcium increased during the maintenance phase, additional increases in the cinacalcet dose were permitted. Main Outcome Measure: The primary end point was the proportion of patients experiencing a reduction in serum calcium of 1 mg/dl or greater (0.25 mmol/liter) at the end of the titration phase. Results: Mean ± sd baseline serum calcium was 12.7 ± 0.8 mg/dl (3.2 ± 0.2 mmol/liter). At the end of titration, a 1 mg/dl or greater reduction in serum calcium was achieved in 15 patients (88%). Fifteen patients (88%) experienced treatment-related adverse events, none of which were serious. The most common adverse events were nausea, vomiting, and paresthesias. Conclusions: In patients with intractable PHPT, cinacalcet reduces serum calcium, is generally well tolerated, and has the potential to fulfill an unmet medical need. PMID:19470620

  7. Effect of dental restorative materials on total antioxidant capacity and calcium concentration of unstimulated saliva

    Science.gov (United States)

    Moghadam, Mona-Momeni; Garcia-Godoy, Franklin; Asatourian, Armen; Aminsobhani, Mohsen; Scarbecz, Mark; Sheibani, Nader

    2017-01-01

    Background To evaluate the effect of dental amalgam and composite restorations on total antioxidant capacity (TAC) and calcium (Ca) ion concentration of unstimulated saliva. Material and Methods Forty-eight children aged 6-10 years selected and divided into three groups of sixteen (8 males, 8 females). In group A and B, samples consisted of two class II dental composite or amalgam restorations, while in group C samples were caries-free (control group). Unstimulated saliva from all samples was collected and TAC was measured by spectrophotometry using an adaptation of 2, 2’-azino-di-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assay. The Ca ion level was estimated by an auto- analyzer. Data were analyzed with one- and two-way ANOVA test, at a p<.05 level of significance. Results Composite samples showed significantly higher TAC and lower Ca ion levels compared to amalgam and caries-free samples (p<.05). The TAC values showed only significant difference between groups (p<.05), while the Ca ion results showed significant differences within and between groups (p<.05). Conclusions Dental composite restorations increased TAC and decreased Ca ion levels more than amalgam restorations in saliva. Gender is an effective factor in changes induced in oral cavity as females showed more emphatic reaction to dental filling materials than males. Statement of Clinical Relevance Patients who have dental restorations, especially dental composites, should pay more attention to their dental hygiene, because dental restorations can increase oxidative stress and decrease Ca ion level in saliva, which might jeopardize remineralization process of tooth structures after demineralization. Key words:Amalgam, caries, composite, saliva, total antioxidant capacity. PMID:28149467

  8. Production of Concentrated Lactococcus lactis subsp. cremoris Suspensions in Calcium Alginate Beads

    Science.gov (United States)

    Morin, Nicole; Bernier-Cardou, Michèle; Champagne, Claude P.

    1992-01-01

    The effect of simultaneous modification of medium composition and growth conditions on the production of Lactococcus lactis subsp. cremoris biomass in calcium alginate beads was studied by the response surface method. Statistical methods of data analysis for unbalanced experiments are illustrated. The media tested were whey, whey supplemented with yeast extract and/or meat extract, milk, and the commercial medium Gold Complete (Nordica). Fermentations were performed at 23°C under pH control (5.6, 6.0, 6.4, or 6.8). In one complete series, 1% CaCO3 was added to the growth media. There were strong interactions between CaCO3 and media, CaCO3 and pH level, and CaCO3, media, and pH level. In media with CaCO3, all first-order interactions between media, pH, and sampling time were significant. The addition of CaCO3 increased cell counts in whey-meat extract medium, but no significant difference was found with the other media. Uncoupling between growth and acidification occurred between 16 and 22 h. Highest counts were obtained on milk and Gold Complete (6 × 1010/g). In CaCO3-containing media, pH influenced cell counts only in whey and in Gold Complete (pH 5.6 and 6.0 giving the best results); pH also influenced the bead mass obtained at the end of the fermentation. Biomass production in alginate gels is proposed as a method of obtaining concentrated cell suspensions without centrifugation or filtration. PMID:16348644

  9. Disease causing mutations of calcium channels.

    Science.gov (United States)

    Lorenzon, Nancy M; Beam, Kurt G

    2008-01-01

    Calcium ions play an important role in the electrical excitability of nerve and muscle, as well as serving as a critical second messenger for diverse cellular functions. As a result, mutations of genes encoding calcium channels may have subtle affects on channel function yet strongly perturb cellular behavior. This review discusses the effects of calcium channel mutations on channel function, the pathological consequences for cellular physiology, and possible links between altered channel function and disease. Many cellular functions are directly or indirectly regulated by the free cytosolic calcium concentration. Thus, calcium levels must be very tightly regulated in time and space. Intracellular calcium ions are essential second messengers and play a role in many functions including, action potential generation, neurotransmitter and hormone release, muscle contraction, neurite outgrowth, synaptogenesis, calcium-dependent gene expression, synaptic plasticity and cell death. Calcium ions that control cell activity can be supplied to the cell cytosol from two major sources: the extracellular space or intracellular stores. Voltage-gated and ligand-gated channels are the primary way in which Ca(2+) ions enter from the extracellular space. The sarcoplasm reticulum (SR) in muscle and the endoplasmic reticulum in non-muscle cells are the main intracellular Ca(2+) stores: the ryanodine receptor (RyR) and inositol-triphosphate receptor channels are the major contributors of calcium release from internal stores.

  10. Effect of Concentration of Structurally-Different Carboxylic Acids on Growth and Aggregation of Calcium Oxalate in Gel Systems

    Institute of Scientific and Technical Information of China (English)

    DENG,Sui-Ping; OUYANG,Jian-Ming

    2007-01-01

    The effect of concentration of structurally-different carboxylic acids such as ethylene diamine tetraacetic acid (H4edta), citric acid (H3cit), tartaric acid (H2tart), and acetic acid (HOAc) on growth and aggregation of calcium oxalate (CaOxa) in gel systems was comparatively investigated. H2tart and H3cit could change the morphology of calcium oxalate monohydrate (COM) and induce the formation of calcium oxalate dihydrate (COD). H4edta could induce the formation of COD at a lower concentration of 0.33 mmol/L and have the strongest ability to inhibit aggregation of COM. HOAc inhibited COM aggregation only at a higher concentration than 500 mmol/L. With increasing the number of carboxylic groups in an acid or increasing the concentration of carboxylic acid, the capacity of this acid to induce COD formation and to inhibit growth and aggregation of COM crystals increased. That is, this capacity followed the order: H4edta>H3cit>H2tart>>HOAc. The result in this work suggested that the presence of H3cit and H2tart in urine played a role in the natural defense against stone formation.

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

    Science.gov (United States)

    Goode, C; Allen, D G

    2011-03-01

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

  12. Antibacterial effect of coffee: calcium concentration in a culture containing teeth/biofilm exposed to Coffea Canephora aqueous extract.

    Science.gov (United States)

    Meckelburg, N; Pinto, K C; Farah, A; Iorio, N L P; Pierro, V S S; dos Santos, K R N; Maia, L C; Antonio, A G

    2014-09-01

    This study determined the changes of calcium concentration in a medium containing teeth/biofilm exposed to Coffea canephora extract (CCE). Enamel fragments were randomly fixed into two 24-well polystyrene plates containing BHI. Pooled human saliva was added to form biofilm on fragments. Specimens were divided into treatment groups (G, n = 8 per group) and treated with 50 μl daily for 1 min per week, as follows: G1, 20% CCE; G2, Milli-Q water (negative control); G3, antibiotic (positive control). Six fragments represented the blank control (G4). The calcium content was observed at baseline, 4 and 7 days of treatment by atomic-absorption spectrophotometry. Cross-sectional hardness of enamel was a demineralization indicator. Calcium increased in the medium after 4 and 7 days of treatment in G1 (3·80 ± 1·3 mg l(-1) and 4·93 ± 2·1 mg l(-1) , respectively) and G3 (4th day = 5·7 ± 1·8 mg l(-1) ; 7th day = 6·7 ± 3·5 mg l(-1) ) (P > 0·05). Calcium from G2 decreased after 7 days, which was different from G3 (P coffee species caused bacterial lysis and consequent release of calcium into the medium. Furthermore, the advantage of coffee as an antibacterial beverage is that it is consumed in a concentrated form (6-10%) as opposed to various medicinal infusions that have shown such effect in vitro and are usually consumed at 1-2%. Therefore, a light roasted C. canephora aqueous extract can be considered as a potential anticariogenic substance. © 2014 The Society for Applied Microbiology.

  13. Comparison of pH and refractometry index with calcium concentrations in preparturient mammary gland secretions of mares.

    Science.gov (United States)

    Korosue, Kenji; Murase, Harutaka; Sato, Fumio; Ishimaru, Mutsuki; Kotoyori, Yasumitsu; Tsujimura, Koji; Nambo, Yasuo

    2013-01-15

    To test the usefulness of measuring pH and refractometry index, compared with measuring calcium carbonate concentration, of preparturient mammary gland secretions for predicting parturition in mares. Evaluation study. 27 pregnant Thoroughbred mares. Preparturient mammary gland secretion samples were obtained once or twice daily 10 days prior to foaling until parturition. The samples were analyzed for calcium carbonate concentration with a water hardness kit (151 samples), pH with pH test paper (222 samples), and refractometry index with a Brix refractometer (214 samples). The sensitivity, specificity, and positive and negative predictive values for each test were calculated for evaluation of predicting parturition. The PPV within 72 hours and the NPV within 24 hours for calcium carbonate concentration determination (standard value set to 400 μg/g) were 93.8% and 98.3%, respectively. The PPV within 72 hours and the NPV within 24 hours for the pH test (standard value set at 6.4) were 97.9% and 99.4%, respectively. The PPV within 72 hours and the NPV within 24 hours for the Brix test (standard value set to 20%) were 73.2% and 96.5%, respectively. Results suggested that the pH test with the standard value set at a pH of 6.4 would be useful in the management of preparturient mares by predicting when mares are not ready to foal. This was accomplished with equal effectiveness of measuring calcium carbonate concentration with a water hardness kit.

  14. The differentiation inducer, dimethyl sulfoxide, transiently increases the intracellular calcium ion concentration in various cell types.

    Science.gov (United States)

    Morley, P; Whitfield, J F

    1993-08-01

    Dimethyl sulfoxide (DMSO) initiates a coordinated differentiation program in various cell types but the mechanism(s) by which DMSO does this is not understood. In this study, the effect of DMSO on intracellular calcium ion concentration ([Ca2+]i) was determined in primary cultures of chicken ovarian granulosa cells from the two largest preovulatory follicles of laying hens, and in three cell lines: undifferentiated P19 embryonal carcinoma cells, 3T3-L1 fibroblasts, and Friend murine erythroleukemia (MEL) cells. [Ca2+]i was measured in cells loaded with the Ca(2+)-specific fluoroprobe Fura-2. There was an immediate (i.e., within 5 sec), transient, two to sixfold increase in [Ca2+]i after exposing all cell types to 1% DMSO. DMSO was effective between 0.2 and 1%. The prompt DMSO-induced [Ca2+]i spike in all of the cell types was not prevented by incubating the cells in Ca(2+)-free medium containing 2 mM EGTA or by pretreating them with the Ca(2+)-channel blockers methoxyverapamil (D600; 100 microM), nifedipine (20 microM), or cobalt (5 mM). However, when granulosa cells, 3T3-L1 cells, or MEL cells were pretreated with lanthanum (La3+; 1 mM), which blocks both Ca2+ channels and membrane Ca2+ pumps, there was a sustained increase in [Ca2+]i in response to 1% DMSO. By contrast, pretreating P19 cells with La3+ (1 mM) did not prolong the DMSO-triggered [Ca2+]i transient. In all cases, the DMSO-induced [Ca2+]i surge was unaffected by pretreating the cells with the inhibitors of inositol phospholipid hydrolysis, neomycin (1.5 mM) or U-73, 122 (2.5 microM). These results suggest that DMSO almost instantaneously triggers the release of Ca2+ from intracellular stores through a common mechanism in cells in primary cultures and in cells of a variety of established lines, but this release is not mediated through phosphoinositide breakdown. This large, DMSO-induced Ca2+ spike may play a role in the induction of cell differentiation by DMSO.

  15. Influence of calcium foliar fertilization on plant growth, nutrient concentrations, and fruit quality of papaya.

    Science.gov (United States)

    Calcium (Ca) is a major plant nutrient that affects cell wall and plasma membrane formation and plays a key role in plant growth and biomass production. It can be used to decrease fruit decay and increase firmness and shelf life. So far, little attention has been paid to investigate the effects of f...

  16. Effects of paeonol on intracellular calcium concentration and expression of RUNX3 in LoVo human colon cancer cells.

    Science.gov (United States)

    Li, Ming; Tan, Shi-Yun; Zhang, Jun; You, Hong-Xia

    2013-05-01

    Paeonol, a major phenolic component of the root bark of Paeonia moutan, is known to exhibit antitumor effects. However, the underlying mechanisms remain unknown. In the present study, the effects of paeonol on cell viability, intracellular calcium concentration and the expression of runt‑related transcription factor 3 (RUNX3) were analyzed in LoVo human colon cancer cells. Results revealed that paeonol markedly reduced LoVo cell viability in a time‑ and dose‑dependent manner. Flow cytometry assays demonstrated that paeonol blocked the cell cycle at the G1 to S transition and significantly induced apoptosis in LoVo cells. Intracellular calcium accumulation occurred following a 48 h treatment with paeonol. Furthermore, RUNX3 gene expression was increased in paeonol‑treated cells. These observations indicate that paeonol possesses antiproliferative properties and apoptosis‑inducing activity. One of the antitumor mechanisms of paeonol may be its apoptosis‑inducing activity through an increased intracellular calcium concentration and the upregulation of RUNX3 expression. Paeonol may be a promising antitumor agent for colon carcinoma treatment.

  17. Early disruption of the actin cytoskeleton in cultured cerebellar granule neurons exposed to 3-morpholinosydnonimine-oxidative stress is linked to alterations of the cytosolic calcium concentration.

    Science.gov (United States)

    Tiago, Teresa; Marques-da-Silva, Dorinda; Samhan-Arias, Alejandro K; Aureliano, Manuel; Gutierrez-Merino, Carlos

    2011-03-01

    Cytoskeleton damage is a frequent feature in neuronal cell death and one of the early events in oxidant-induced cell injury. This work addresses whether actin cytoskeleton reorganization is an early event of SIN-1-induced extracellular nitrosative/oxidative stress in cultured cerebellar granule neurons (CGN). The actin polymerization state, i.e. the relative levels of G-/F-actin, was quantitatively assessed by the ratio of the fluorescence intensities of microscopy images obtained from CGN double-labelled with Alexa594-DNase-I (for actin monomers) and Bodipy-FL-phallacidin (for actin filaments). Exposure of CGN to a flux of peroxynitrite as low as 0.5-1μM/min during 30min (achieved with 0.1mM SIN-1) was found to promote alterations of the actin cytoskeleton dynamics as it increases the G-actin/F-actin ratio. Because L-type voltage-operated Ca(2+) channels (L-VOCC) are primary targets in CGN exposed to SIN-1, the possible role of Ca(2+) dynamics on the perturbation of the actin cytoskeleton was also assessed from the cytosolic Ca(2+) concentration response to the L-VOCC's agonist FPL-64176 and to the L-VOCC's blocker nifedipine. The results showed that SIN-1 induced changes in the actin polymerization state correlated with its ability to decrease Ca(2+) influx through L-VOCC. Combined analysis of cytosolic Ca(2+) concentration and G-actin/F-actin ratio alterations by SIN-1, cytochalasin D, latrunculin B and jasplakinolide support that disruption of the actin cytoskeleton is linked to cytosolic calcium concentration changes.

  18. The effect of organolead and -tin compounds on signal transduction in vitro: Investigations on the cytosolic free calcium concentration; Der Einfluss von organischen Blei- und Zinnverbindungen auf die Signaltransduktion in vitro: Untersuchungen zur Veraenderung der zytosolischen freien Calciumkonzentration

    Energy Technology Data Exchange (ETDEWEB)

    Ade, T.

    1996-03-01

    The cellular effects of organolead and -tin compounds are not yet precisely understood. However, on the basis of their immuno- and neurotoxicity it is most likely that these substances interfere with cellular signal transduction. For this reason the effect on cytosolic free calcium concentration was investigated in this study. The organometals used induce a persistent increase in cytosolic free calcium concentration in human leukaemia HL-60 cells as well as in neuroblastoma NG-108-15 cells. Studies of the mechanism of the organometal effect with EGTA and calcium channel blockers revealed that an influx of calcium from the extracellular space is responsible for the organometal-induced calcium elevation in HL-60 cells. The effect of the investigated lead compounds and tributyltin is due to calcium channel opening in the plasma membrane. The same is true for the NG108-15 cells. Activation of distinct receptor-mediated signal transduction is not the reason for channel opening. The regulation of cytosolic free calcium concentration was affected by inhibition of plasmamembrane Ca{sup 2+}-ATPases as well as by disturbance of other ion gradients. A consequence of the organometal effect on the cytosolic calcium concentration is the activation of a cPLA{sub 2} and perhaps the induction of apoptosis. These results contribute towards the understanding of biochemical mechanisms causing the injury of vells by organometals. (orig.) [Deutsch] Die zellulaeren Wirkungsmechanismen organischer Blei- und Zinnverbindungen sind zum grossen Teil nicht verstanden. Die immuno- und neurotoxischen Effekte dieser Xenobiotika lassen jedoch die Beeinflussung der Signalwege in den Zellen vermuten. Daher lag der Schwerpunkt dieser Arbeit in der Untersuchung der Signaluebertragungswege und der damit verbundenen Regulation des Calciums. Sowohl in immunkompetenten Zellen (HL-60) wie auch in neuronalen Zellen (NG108-15) induzierten die untersuchten Organometalle eine persistente Erhoehung der

  19. Antioxidant effect of hyaluronan on polymorphonuclear leukocyte-derived reactive oxygen species is dependent on its molecular weight and concentration and mainly involves the extracellular space

    Directory of Open Access Journals (Sweden)

    Rafał Krasiński

    2009-05-01

    Full Text Available Introduction: Hyaluronan (HA, a component of the extracellular matrix, may regulate immune cell functions through its interactions with cellular receptors. Besides its effect on cytokine and chemokine production, its antioxidant properties have been described. However, the mechanisms of this are not fully elucidated. The aim of this study was to evaluate the relationship between HA concentration and molecular weight and its antioxidant properties towards human neutrophils. Also assessed was whether the antioxidant effect of HA is connected with a reduction in intracellular oxygen potential, which could indicate its direct effect on neutrophil respiratory burst.Materials/Methods: The relationship between HA’s antioxidant properties and its concentration and molecular weight was assessed by the luminol-enhanced chemiluminescence method (CL. To evaluate the effect of HA on intracellular oxygen potential selectively, the dihydrorhodamine 123 (DHR123 flow cytometric method was used.Results: Reduction of both HA molecular weight and its concentration decreased its antioxidant properties in the CL method. A selective effect of HA on intracellular oxygen potential measured by the DHR123 method was not shown.Conclusions: The antioxidant properties of HA are related to both its molecular weight and its concentration. The lack of an antioxidant effect of HA in the DHR123 test compared with a significant reduction in CL values at the same HA concentration suggests that HA acts mainly as a chemical ROI scavenger in the extracellular space.

  20. Low extracellular calcium enhances beta cell sensitivity to the stimulatory influence of 1,25-dihydroxyvitamin D3 on insulin release by islets from vitamin D3-deficient rats.

    Science.gov (United States)

    Faure-Dussert, A G; Delbancut, A P; Billaudel, B J

    1997-07-01

    The beneficial effect of 1,25-dihydroxyvitamin D3 [1,25 (OH)2 D3] on insulin secretion from beta cells in hypocalcemic vitamin D3-deficient rats is now well established. Moreover, few data concerning the mechanism of 1,25 (OH) 2D3 efficiency as a function of the severity of hypocalcemia. In the present experiment, we submitted islets from vitamin D3-deficient rats to in vitro exposure to a range of decreasing extracellular Ca2+ concentrations ([Ca2+]ex), from 0.5 mM to 0.6 mM, during a 6-h 10-8 M 1,25 (OH) 2D3 induction. Thereafter, we compared the effect of this pretreatment on the islets' insulin response to a given stimulus. Various stimuli were used, and we measured in parallel the variations of 86Rb+ and 45Ca2+ efflux and insulin release into the perifusion medium. In the presence of 1,25 (OH) 2D3, we observed an inverse correlation between the [Ca2+]ex pre-exposure and the amplitude of the insulin response to certain stimuli studied, suggesting that beta cells that were pre-exposed to low [Ca2+]ex became more sensitive to the beneficial effect of 1,25 (OH) 2D3 on insulin release. This effect was observed when beta cells were activated by acetylcholine but only during its second phase of stimulation, and more particularly with the barium plus theophylline stimulus. In contrast, insulin release was not affected by [Ca2+]ex pre-exposure during 1,25 (OH) 2D3 induction in response to acetylcholine during its first phase of stimulation, thus excluding any mechanism mediated via nutrient pathways, membrane depolarization, or inositol triphosphate (IP3)-dependent events. Moreover, the islets that were pre-exposed to a 10-fold [Ca2+]ex exhibited only a 50% lower 45Ca2+ content after 45Ca2+ loading, suggesting a different or relatively more efficient storage capacity in the presence of low extracellular calcium. Studies of 45Ca2+ efflux showed that the mobilization of Ca2+ stores induced by a barium plus theophylline stimulus, in the absence of calcium in the

  1. Serum concentrations of calcium, phosphorus, and 25-hydroxyvitamin d in captive African elephants (Loxodonta africana).

    Science.gov (United States)

    Miller, Michele; Chen, Tai C; Holick, Michael F; Mikota, Susan; Dierenfeld, Ellen

    2009-06-01

    Seventy-two serum samples were collected from 14 healthy African elephants (Loxodonta africana), including three calves, to test for 25-hydroxyvitamin D [25(OH)D] as well as for performing biochemical panels. Samples were collected between July 1997 and January 2008 to establish normal 25(OH)D values for the species and to examine the relationship of season and time on these values. Although the number of samples from the calves was small (n = 7), there was no statistically significant difference in the mean 25(OH)D levels between adults and calves (15.7 +/- 7.7 ng/ml versus 17.1 +/- 5.8 ng/ml, P > 0.05, respectively). The comparison of mean and individual values among seasons showed some variation, but was not statistically different; therefore, all values were combined for further analyses. The mean value of 25(OH)D for all samples was 15.8 +/- 7.5 ng/ml (n = 72), with a 95% confidence interval of 14.0-17.6 ng/ml. There did not appear to be a direct correlation between 25(OH)D levels and calcium (Ca), phosphorus (P), or calcium:phosphorus ratio (Ca:P) based on regression analyses (P < 0.05). Values measured approximated normal distributions. Mean calcium value was 10.5 +/- 0.6 mg/dl (n = 61); mean phosphorus value was 5.2 +/- 0.8 mg/dl (n = 50); and mean Ca:P was 2.06 +/- 0.34. Since all animals appeared healthy during the course of sample collection, and bone density on foot radiographs was assessed as good, the results are considered to be normal for this herd. With the incidence of joint disease in older elephants, and metabolic bone disease in hand-reared calves, these values will provide a basis for further studies of calcium metabolism in elephants.

  2. The involvement of intracellular calcium ion concentration and calmodulin in the 25-hydroxylation of cholecalciferol in ovine and rat liver.

    Science.gov (United States)

    Corlett, S C; Chaudhary, M S; Tomlinson, S; Care, A D

    1987-08-01

    The effect of Ca2+ ion concentration on the 25 hydroxylation of tritiated cholecalciferol (3HD3) was investigated using homogenates of ovine liver from vitamin D replete sheep. A significant decrease in the production of 25 hydroxycholecalciferol (25OHD3) was observed when the concentration of Ca2+ in the homogenate was raised above 0.68 mmol/l by the addition of calcium gluconate. Similarly, a final concentration of 37 mumol EGTA/1 (equivalent to a Ca2+ concentration of 26.5 nmol/l) was associated with a 50% reduction of 25OHD3 production. That is, a broad bell-shaped relationship was observed between the production of 25OHD3 and the Ca2+ concentration in the homogenate. These changes in the rate of production of 25OHD3 were reproduced with hepatocytes from vitamin D replete rats, prepared by collagenase perfusion, using the drugs dantrolene sodium (DaNa) to reduce (ED50 = 57 mmol/l) and veratridine to increase (ED50 = 550 mmol/l) the intracellular Ca2+ concentration. Hepatocytes from vitamin D replete rats also showed a reduction in 25 hydroxylation of D3 (ED50 = 6 ng/ml) in response to the addition of 1-25 dihydroxycholecalciferol (1-25 (OH)2D3). The calmodulin antagonists; W7, compound 48/80, trifluoperazine (TFP) and calmidazolium (R24571) were all found to effect a dose response inhibition of the 25 hydroxylation of cholecalciferol by homogenates of ovine liver. R24571 had a similar inhibitory effect (ED50 = 70 mumol/l) upon the 25 hydroxylase enzyme of rat hepatocytes. It is concluded that the 25 hydroxylation of cholecalciferol in liver of vitamin D replete rats and sheep is calcium sensitive and is reduced in the presence of increased concentrations of 1,25(OH)2D3. Calmodulin may also be involved in the regulation of hepatocyte 25-hydroxylase activity by Ca2+.

  3. Amelioration of boron toxicity in sweet pepper as affected by calcium management under an elevated CO2 concentration.

    Science.gov (United States)

    Piñero, María Carmen; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2017-03-10

    We investigated B tolerance in sweet pepper plants (Capsicum annuun L.) under an elevated CO2 concentration, combined with the application of calcium as a nutrient management amelioration technique. The data show that high B affected the roots more than the aerial parts, since there was an increase in the shoot/root ratio, when plants were grown with high B levels; however, the impact was lessened when the plants were grown at elevated CO2, since the root FW reduction caused by excess B was less marked at the high CO2 concentration (30.9% less). Additionally, the high B concentration affected the membrane permeability of roots, which increased from 39 to 54% at ambient CO2 concentration, and from 38 to 51% at elevated CO2 concentration, producing a cation imbalance in plants, which was differentially affected by the CO2 supply. The Ca surplus in the nutrient solution reduced the nutritional imbalance in sweet pepper plants produced by the high B concentration, at both CO2 concentrations. The medium B concentration treatment (toxic according to the literature) did not result in any toxic effect. Hence, there is a need to review the literature on critical and toxic B levels taking into account increases in atmospheric CO2.

  4. Immediate response of Ca2+ concentration in myocardial cells against oxidation stress by extracellular photosensitization reaction using Talaporfin sodium for the arrhythmia treatment application

    Science.gov (United States)

    Ogawa, Emiyu; Takahashi, Mei; Ito, Arisa; Arai, Tsunenori

    2014-02-01

    We studied the immediate response of myocardial cells by continuous observation using confocal microscope against oxidation stress by extracellular photosensitization reaction using Talaporfin sodium for tachyarrhythmia treatment application. Immediate response in order from several seconds to several minutes is required for the arrhythmia treatment since operators should judge the therapeutic effect during the tachyarrhythmia ablation procedure. To understand the immediate response of myocardial cells, we measured the intracellular Ca2+ concentration using fluo-4 AM during and after the extracellular photosensitization reaction. Talaporfin sodium concentration was varied 10-30 μg/ml. A red diode laser of 663 nm in wavelength was irradiated under the microscope with the radiant exposure of 40 J/cm2 and irradiance of 0.29 W/cm2. We observed the fluorescence image of fluo-4 AM each 400 ms during until 10 min after the photosensitization reaction. The myocardial cell beatings were stopped about 2 s after the beginning of the laser irradiation. The blebs were formed with the Ca2+ inflow. The intracellular Ca2+ was re-decreased after the bleb formation and then the cell necrosis was induced. The cell lethality 10 min after the laser irradiation was less than bleb formation ratio. The time response of the cell necrosis was shortened with the photosensitizer concentration increasing and the minimum average value was 209 s in the case of the 30 μg/ml in photosensitizer concentration and 40 J/cm2 in the radiant exposure. We think this extracellular photosensitization reaction may be applicable to tachyarrhythmia treatment in terms of its immediate response.

  5. Novel concentration method for the detection of norovirus and sapovirus from water using minute particles of amorphous calcium phosphate.

    Science.gov (United States)

    Shinohara, Michiyo; Uchida, Kazue; Shimada, Shin-Ichi; Tomioka, Kyoko; Suzuki, Noriko; Minegishi, Toshitaka; Kawahashi, Sachie; Yoshikawa, Yuko; Ohashi, Norio

    2011-06-01

    A novel concentration method using minute particles of amorphous calcium phosphate (ACP) was developed for the detection of caliciviruses including norovirus and sapovirus, agents of human gastroenteritis, from water. In seeding experiments with feline calicivirus (FCV), ACP particles were able to adsorb efficiently the viruses in water, and the FCV-concentrated solution was obtained by dissolution of the virus-adsorbing ACP particles with citric acid after centrifugation. By quantitative real-time RT-PCR, the recovery efficiencies from 300 ml ultrapure water seeded with 10³, 10⁴ and >10⁵ copies of FCV were 48, 68 and >100 %, respectively. A comparative study showed that in the addition of viruses at sapovirus (genogroups I, II, IV and V) from river water. The data suggest that our new viral concentration is a rapid, simple, cost efficient and high virus recovery method, and it can be used for routine monitoring of norovirus and sapovirus in water, especially environmental water.

  6. Evidence for Tonic Control by the GABAA Receptor of Extracellular D-Serine Concentrations in the Medial Prefrontal Cortex of Rodents

    Directory of Open Access Journals (Sweden)

    Asami Umino

    2017-08-01

    Full Text Available Endogenous D-serine is a putative dominant co-agonist for the N-methyl-D-aspartate glutamate receptor (NMDAR in the mammalian forebrain. Although the NMDAR regulates the higher order brain functions by interacting with various neurotransmitter systems, the possible interactions between D-serine and an extra-glutamatergic system largely remain elusive. For the first time, we show in the rat and mouse using an in vivo microdialysis technique that the extracellular D-serine concentrations are under tonic increasing control by a major inhibitory transmitter, GABA, via the GABAA (GABAAR in the medial prefrontal cortex (mPFC. Thus, an intra-mPFC infusion of a selective GABAAR antagonist, bicuculline (BIC, caused a concentration-dependent and reversible decrease in the extracellular levels of D-serine in the rat mPFC without affecting those of another intrinsic NMDAR coagonist, glycine and an NMDAR agonist, L-glutamate. The decreasing effects of BIC were eliminated by co-infusion of a selective GABAA agonist, muscimol (MUS and were mimicked by a GABAA antagonist, gabazine (GBZ. In contrast, selective blockade of the GABAB or homomeric ρGABAA (formerly GABAC receptor by saclofen or (1,2,5,6-tetrahydropyridin-4-yl-methylphosphinic acid (TPMPA, respectively, failed to downregulate the prefrontal extracellular D-serine levels. Moreover, the local BIC application attenuated the ability of NMDA given to the mPFC to increase the cortical extracellular concentrations of taurine, indicating the hypofunction of the NMDAR. Finally, in the mouse mPFC, the reduction of the extracellular D-serine levels by a local injection of BIC into the prefrontal portion was replicated, and was precluded by inhibition of the neuronal or glial activity by co-local injection with tetrodotoxin (TTX or fluorocitrate (Fluo, respectively. These findings suggest that the GABAAR-mediated regulation of the D-serine signaling may exert fine-tuning of the NMDAR function and require both

  7. Lack of effect on blood lipid and calcium concentrations of young men on changing from white to wholemeal bread.

    Science.gov (United States)

    Heaton, K W; Manning, A P; Hartog, M

    1976-01-01

    1. When nineteen "free-living" male students, who normally ate 231 (SEM 14) g white bread/d changed to wholemeal bread for a 19-week period, there was no significant change in body-weight, plasma cholesterol or plasma triglyceride levels. These values, as well as plasma concentrations of calcium, phosphate, urate and haemoglobin, remained essentially the same as those for a control group. 2. Increasing the wheat-fibre intake by eating wholemeal bread is not an effective method for reducing blood lipids levels, at least in healthy young men with a moderate bread intake.

  8. External bioenergy-induced increases in intracellular free calcium concentrations are mediated by Na+/Ca2+ exchanger and L-type calcium channel.

    Science.gov (United States)

    Kiang, Juliann G; Ives, John A; Jonas, Wayne B

    2005-03-01

    External bioenergy (EBE, energy emitted from a human body) has been shown to increase intracellular calcium concentration ([Ca2+]i, an important factor in signal transduction) and regulate the cellular response to heat stress in cultured human lymphoid Jurkat T cells. In this study, we wanted to elucidate the underlying mechanisms. A bioenergy specialist emitted bioenergy sequentially toward tubes of cultured Jurkat T cells for one 15-minute period in buffers containing different ion compositions or different concentrations of inhibitors. [Ca2+], was measured spectrofluorometrically using the fluorescent probe fura-2. The resting [Ca2+]i in Jurkat T cells was 70 +/- 3 nM (n = 130) in the normal buffer. Removal of external calcium decreased the resting [Ca2+]i to 52 +/- 2 nM (n = 23), indicating that Ca2+ entry from the external source is important for maintaining the basal level of [Ca2+]i. Treatment of Jurkat T cells with EBE for 15 min increased [Ca2+]i by 30 +/- 5% (P EBE did not attenuate [Ca2+]i responsiveness to EBE. Removal of external Ca2+ or Na+, but not Mg2+, inhibited the EBE-induced increase in [Ca2+]i. Dichlorobenzamil, an inhibitor of Na+/Ca2+ exchangers, also inhibited the EBE-induced increase in [Ca2+]i in a concentration-dependent manner with an IC50 of 0.11 +/- 0.02 nM. When external [K+] was increased from 4.5 mM to 25 mM, EBE decreased [Ca2+]i. The EBE-induced increase was also blocked by verapamil, an L-type voltage-gated Ca2+ channel blocker. These results suggest that the EBE-induced [Ca2+]i increase may serve as an objective means for assessing and validating bioenergy effects and those specialists claiming bioenergy capability. The increase in [Ca2+]i is mediated by activation of Na+/Ca2+ exchangers and opening of L-type voltage-gated Ca2+ channels.

  9. PROVISION OF VITAMINS AND CALCIUM IN RHEUMATOID ARTHRITIS: ESTIMATION OF INTAKE AND PLASMA CONCENTRATIONS

    Directory of Open Access Journals (Sweden)

    V. N. Khodyrev

    2015-01-01

    Full Text Available Objective: to study the actual intake of vitamins and calcium and their provision in rheumatoid arthritis (RA in the Middle Urals. Subjects and methods. The case-control method was used to form 150 pairs of RA patients aged 55.31±11.3 years. Their actual nutrition was studied from the frequency of food intake for a month, by applying a questionnaire. Based on the obtained food consumption data, the authors calculated the daily intake of vitamins A, B2, C, E, β-carotene, and calcium. The plasma levels of these factors were measured in 40% of the random patient sample and in 68 (45% control persons. A complete clinical examination included the evaluation of patients' general health and articular status, inflammatory activity assessment with DAS28, laboratory tests (general blood and urine analyses, estimation of the levels of transaminases, creatinine, electrolytes, C-reactive protein, and rheumatoid factor, and instrumental examination, involving electrocardiography and joint X-ray. Results and discussion. The study demonstrated that actual nutrition was depleted of vitamins A, C, and B2 in the patients with RA as compared to the controls. Inadequate provision of vitamin C, β-carotene, riboflavin, and calcium was found in RA. The inconsistency between the consumption of vitamins C, B2, and β-carotene and their plasma levels could suggest increased demands for these nutrients in RA. The findings should undergo detailed studies; first of all, this concerns the comparison of intake of the nutrients and their provision with the most important clinical characteristics of RA, such as duration, progression, activity, X-ray stage, and the presence of rheumatoid factor. The knowledge of these matters could, in our opinion, improve the results of therapy and prognosis in RA.

  10. Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

    Science.gov (United States)

    Betz, N. A.; Westhoff, B. A.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Our laboratory has purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) from intact bovine cerebral cortex cells. Evidence presented here demonstrates that sensitivity to CeReS-18-induced growth inhibition in BALB-c 3T3 cells is influenced by calcium, such that a decrease in the calcium concentration in the growth medium results in an increase in sensitivity to CeReS-18. Calcium did not alter CeReS-18 binding to its cell surface receptor and CeReS-18 does not bind calcium directly. Addition of calcium, but not magnesium, to CeReS-18-inhibited 3T3 cells results in reentry into the cell cycle. A greater than 3-hour exposure to increased calcium is required for escape from CeReS-18-induced growth inhibition. The calcium ionophore ionomycin could partially mimic the effect of increasing extracellular calcium, but thapsigargin was ineffective in inducing escape from growth inhibition. Increasing extracellular calcium 10-fold resulted in an approximately 7-fold increase in total cell-associated 45Ca+2, while free intracellular calcium only increased approximately 30%. However, addition of CeReS-18 did not affect total cell-associated calcium or the increase in total cell-associated calcium observed with an increase in extracellular calcium. Serum addition induced mobilization of intracellular calcium and influx across the plasma membrane in 3T3 cells, and pretreatment of 3T3 cells with CeReS-18 appeared to inhibit these calcium mobilization events. These results suggest that a calcium-sensitive step exists in the recovery from CeReS-18-induced growth inhibition. CeReS-18 may inhibit cell proliferation through a novel mechanism involving altering the intracellular calcium mobilization/regulation necessary for cell cycle progression.

  11. Effect of high calcium concentration influents on enhanced biological phosphorus removal process; Efecto del proceso de eliminacion biologica de fosforo en enfluentes con elevadas concentraciones de calcio

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

    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{sub 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{sub P}O4 decline. (Author) 18 refs.

  12. Changes in Sodium, Calcium, and Magnesium Ion Concentrations That Inhibit Geobacillus Biofilms Have No Effect on Anoxybacillus flavithermus Biofilms.

    Science.gov (United States)

    Somerton, B; Lindsay, D; Palmer, J; Brooks, J; Flint, S

    2015-08-01

    This study investigated the effects of varied sodium, calcium, and magnesium concentrations in specialty milk formulations on biofilm formation by Geobacillus spp. and Anoxybacillus flavithermus. The numbers of attached viable cells (log CFU per square centimeter) after 6 to 18 h of biofilm formation by three dairy-derived strains of Geobacillus and three dairy-derived strains of A. flavithermus were compared in two commercial milk formulations. Milk formulation B had relatively high sodium and low calcium and magnesium concentrations compared with those of milk formulation A, but the two formulations had comparable fat, protein, and lactose concentrations. Biofilm formation by the three Geobacillus isolates was up to 4 log CFU cm(-2) lower in milk formulation B than in milk formulation A after 6 to 18 h, and the difference was often significant (P ≤ 0.05). However, no significant differences (P ≤ 0.05) were found when biofilm formations by the three A. flavithermus isolates were compared in milk formulations A and B. Supplementation of milk formulation A with 100 mM NaCl significantly decreased (P ≤ 0.05) Geobacillus biofilm formation after 6 to 10 h. Furthermore, supplementation of milk formulation B with 2 mM CaCl2 or 2 mM MgCl2 significantly increased (P ≤ 0.05) Geobacillus biofilm formation after 10 to 18 h. It was concluded that relatively high free Na(+) and low free Ca(2+) and Mg(2+) concentrations in milk formulations are collectively required to inhibit biofilm formation by Geobacillus spp., whereas biofilm formation by A. flavithermus is not impacted by typical cation concentration differences of milk formulations.

  13. Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Hlaing, Nwe Ni, E-mail: nwenihlaing76@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Vignesh, K., E-mail: vignesh134@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Anano Sphere Sdn Bhd, Lorong Industri 11, Kawasan Industri Bukit Panchor, 14300 Nibong Tebal, Penang (Malaysia); Sreekantan, Srimala, E-mail: srimala@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Pung, Swee-Yong [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Hinode, Hirofumi; Kurniawan, Winarto [Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Othman, Radzali [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Malacca (Malaysia); Thant, Aye Aye [Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Mohamed, Abdul Rahman [Low Carbon Economy (LCE) Research Group, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Salim, Chris [Department of Environmental Engineering, Surya University, Tangerang 15810, Banten (Indonesia)

    2016-02-15

    Graphical abstract: Carbonation conversions of (a) CC, (b) CH-2, (c) CH-4, (d) CH-6, (e) CH-8 precursor adsorbents for 10 cycles. - Highlights: • Ca(OH){sub 2} precursor was synthesized using precipitation method. • The effect of CTAB concentration on the synthesis of Ca(OH){sub 2} was studied. • The sorbent synthesized using 0.8 M of CTAB showed good CO{sub 2} adsorption capacity. • The cyclic stability of Ca(OH){sub 2} was increased with increase of CTAB concentration. - Abstract: Calcium hydroxide (Ca(OH){sub 2}) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH){sub 2} based adsorbents for carbon dioxide (CO{sub 2}) capture. The effect of CTAB concentration (0.2–0.8 M) on the structure, morphology and CO{sub 2} adsorption performance of Ca(OH){sub 2} was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG–DTA) techniques. The phase purity, crystallite size, Brunauer–Emmett–Teller (BET) surface area and CO{sub 2} adsorption performance of Ca(OH){sub 2} precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH){sub 2} phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH){sub 2} precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

  14. Physicochemical properties and in vitro cytocompatibility of modified titanium surfaces prepared via micro-arc oxidation with different calcium concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sui-Dan; Zhang, Hui [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China); Dong, Xu-Dong [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC V6T 1Z3 (Canada); Ning, Cheng-Yun [College of Material Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Fok, Alex S.L. [Minnesota Dental Research Center of Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55414 (United States); Wang, Yan, E-mail: wyan65@163.com [Guanghua School of Stomatology, Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou 510055 (China)

    2015-02-28

    Highlights: • MAO coating improves the surface characteristics and cytocompatibility of titanium. • Composition of MAO coating varies with the electrolyte concentration. • MAO coating properties can be optimized by adjusting the electrolyte concentration. • Higher CA concentration contributes to more favorable MAO coating cytocompatibility. - Abstract: Objective: To explore the effect of calcium concentration in the electrolyte solution on the physicochemical properties and biocompatibility of coatings formed by micro-arc oxidation (MAO) on titanium surfaces. Methods: The surfaces of pure titanium plates were modified by MAO in an electrolytic solution containing calcium acetate (CA; C{sub 4}H{sub 6}CaO{sub 4}) at concentrations of 0.05, 0.1, 0.2, or 0.3 M and β-glycerophosphate disodium salt pentahydrate (β-GP; C{sub 3}H{sub 7}Na{sub 2}O{sub 6}P·5H{sub 2}O) at a fixed concentration of 0.02 M. Surface topography, elemental characteristics, phase composition, and roughness were investigated by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, and a surface roughness tester, respectively. To assess the cytocompatibility and osteoinductivity of the surfaces, MC3T3-E1 preosteoblasts were cultured on the surfaces in vitro, and cell morphology, adhesion, proliferation, and differentiation were observed. Results: The porous MAO coating was composed primarily of TiO{sub 2} rutile and anatase. The amount of TiO{sub 2} rutile, the Ca/P ratio, and the surface roughness of the MAO coating increased with increasing CA concentration in the electrolyte solution. Ca{sub 3}(PO{sub 4}){sub 2}, CaCO{sub 3}, and CaTiO{sub 3} were formed on MAO-treated surfaces prepared with CA concentrations of 0.2 and 0.3 M. Cell proliferation and differentiation increased with increasing CA concentration, with MC3T3-E1 cells exhibiting favorable morphologies for bone–implant integration. Conclusions: MAO coating improves the surface characteristics and

  15. Expression of the calcium receptor CaR in the parathyroid of secondary hyperparathyroidism patients

    Institute of Scientific and Technical Information of China (English)

    王宁宁; 王笑云; 彭韬; 吴宏飞; 胡建明; 赵卫红; 俞香宝

    2004-01-01

    @@ The effects of calcium on parathyroid hormone (PTH) has further discovered in recent years. It has been known that calcium ion concentration in the extracellular fluid is a major determinant of PTH secretion. The relationship between serum intact PTH (iPTH) and calcium ion levels is described by a sigmoidal curve. The calcium concentration that produces half-maximal change in PTH release (the midpoint between maximal and minimal change in PTH release) represents the sensitivity of parathyroid cells to serum calcium. In secondary hyperparathyroidism (SHPT) patients, higher calcium concentrations are needed to suppress PTH secretion, as demonstrated by the PTH-calcium sigmoidal curve. The loss of physiological control over the secretory function and growth of parathyroid tissue in hyperparathyroid disease is still incompletely understood.

  16. Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. The effect of different dietary calcium and phosphorus concentrations and ratios on nutrient digestibility.

    Science.gov (United States)

    Wilkinson, S J; Bradbury, E J; Thomson, P C; Bedford, M R; Cowieson, A J

    2014-07-01

    A total of 600 Ross 308-day-old male broiler chicks were used in a 28 day digestibility study to investigate the interaction between dietary calcium (Ca) and non-phytate phosphorus (nPP) on the digestibility of minerals and amino acids. Diets were formulated to be nutritionally adequate except for Ca and nPP. Fifteen mash diets based on corn and soya bean meal with varying concentrations of Ca (6.4 to 12.0 g/kg) and nPP (2.4 to 7.0 g/kg) were used. Diets were clustered around total densities of Ca and nPP of 12, 13.5 or 15.0 (g/kg) and within each density, a range of five Ca : nPP ratios (1.14 : 1, 1.5 : 1, 2.0 : 1, 2.75 : 1 and 4.0 : 1) were fed. Birds had free access to feed and water throughout the study. At day 28, birds were euthanised for the determination of apparent ileal mineral and amino acid digestibility. Data were modelled in R version 2.15 using a linear mixed-effects model and interrogation of the data was performed by fitting a low order polynomial function. At high Ca concentrations, increasing nPP led to an increase in the apparent digestibility of minerals. Apparent ileal digestibility of phosphorus (P) was enhanced with increasing dietary nPP up to 5.5 g/kg beyond which no improvements were found. Maximal Ca digestibility was found in diets with >8.0 g/kg Ca with concomitant low concentrations of nPP. Diets with a broader Ca : nPP ratio improved the digestibility of Ca but were deleterious to the digestibility of P. In this study, apparent digestibility of amino acids was broadly unaffected by dietary Ca and nPP concentrations. However, interactions between Ca and nPP were observed for the digestibility of glutamine, tyrosine and methionine (all P<0.001). Nitrogen digestibility showed discrete optima around 10.0 and 5.0 g/kg nPP and Na digestibility was maximised around 8 to 9.0 g/kg Ca and 4.5 to 5.4 g/kg nPP. These data show that the ratio of Ca : nPP is more influential to mineral digestibility than the absolute dietary concentration of each

  17. Inhibition of Brain Swelling after Ischemia-Reperfusion by β-Adrenergic Antagonists: Correlation with Increased K+ and Decreased Ca2+ Concentrations in Extracellular Fluid

    Directory of Open Access Journals (Sweden)

    Dan Song

    2014-01-01

    Full Text Available Infarct size and brain edema following ischemia/reperfusion are reduced by inhibitors of the Na+, K+, 2Cl−, and water cotransporter NKCC1 and by β1-adrenoceptor antagonists. NKCC1 is a secondary active transporter, mainly localized in astrocytes, driven by transmembrane Na+/K+ gradients generated by the Na+,K+-ATPase. The astrocytic Na+,K+-ATPase is stimulated by small increases in extracellular K+ concentration and by the β-adrenergic agonist isoproterenol. Larger K+ increases, as occurring during ischemia, also stimulate NKCC1, creating cell swelling. This study showed no edema after 3 hr medial cerebral artery occlusion but pronounced edema after 8 hr reperfusion. The edema was abolished by inhibitors of specifically β1-adrenergic pathways, indicating failure of K+-mediated, but not β1-adrenoceptor-mediated, stimulation of Na+,K+-ATPase/NKCC1 transport during reoxygenation. Ninety percent reduction of extracellular Ca2+ concentration occurs in ischemia. Ca2+ omission abolished K+ uptake in normoxic cultures of astrocytes after addition of 5 mM KCl. A large decrease in ouabain potency on K+ uptake in cultured astrocytes was also demonstrated in Ca2+-depleted media, and endogenous ouabains are needed for astrocytic K+ uptake. Thus, among the ionic changes induced by ischemia, the decrease in extracellular Ca2+ causes failure of the high-K+-stimulated Na+,K+-ATPase/NKCC1 ion/water uptake, making β1-adrenergic activation the only stimulus and its inhibition effective against edema.

  18. Effects of high concentrations of calcium salts in the substrate and its pH on the growth of selected rhododendron cultivars

    Directory of Open Access Journals (Sweden)

    Piotr Giel

    2011-07-01

    Full Text Available For proper growth and development, rhododendrons need acidic soils, whereas calcium carbonate (CaCO3 in the substrate markedly limits their growth. In this study, we analysed the reactions of rhododendrons to high concentrations of calcium salts and pH in the substrate. We used 4-month-old seedlings of Rhododendron 'Cunningham's White' and 1.5-year-old seedlings and rooted cuttings of R. 'Cunningham's White' and R. 'Catawbiense Grandiflorum'. Their reactions depended mostly on calcium salt type added to the substrate (sulphate or carbonate. An increase in concentrations of phenolic compounds was detected mostly in roots of the plants grown in a substrate with a high calcium carbonate content. Addition of calcium salts to the substrate caused a significant rise in total nonstructural carbohydrates in leaves and roots of the studied plants. As compared to the control, an increase in substrate pH in the variant with calcium carbonate limited the activity of acid phosphatase, while lowering of substrate pH in the variant with calcium sulphate, significantly increased its activity. Along with the rise in substrate pH, a remarkable increase was observed in the activity of nonspecific dehydrogenase (DHA in the substrate with CaCO3, as compared to the control. Unfavourable soil conditions (high calcium content and alkaline pH caused a decrease in assimilation of minerals by the studied plants (mostly phosphorus and manganese. Our results show that the major factor limiting rhododendron growth is an increase in substrate pH, rather than an increase in the concentration of calcium ions.

  19. Effect of glucose stimulation on /sup 45/calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-02-01

    Glucose-stimulated /sup 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/..mu..g 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/..mu..g DNA. On incubation with /sup 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.

  20. Inhibition effects of high calcium concentration on anaerobic biological treatment of MSW leachate.

    Science.gov (United States)

    Xia, Yi; He, Pin-Jing; Pu, Hong-Xia; Lü, Fan; Shao, Li-Ming; Zhang, Hua

    2016-04-01

    With the increasing use of municipal solid waste incineration (MSWI) and more stringent limits on landfilling of organic waste, more MSWI bottom ash is being landfilled, and the proportion of inorganic wastes in landfills is increasing, causing the increased Ca concentrations in landfill leachate. In this research, the inhibition effect of Ca concentration on the anaerobic treatment of landfill leachate was studied using a biochemical methane potential experiment. Slight inhibition of methane production occurred when the addition of Ca concentration was less than 2000 mg/L. When the addition of Ca concentration was between 6000 and 8000 mg/L, methane production was significantly reduced (to 29.4-34.8 % of that produced by the BLK reactor), and the lag phase was increased from 8.55 to 16.32 d. Moreover, when the dosage of Ca concentration increased from zero to 8000 mg/L, reductions in solution Ca concentration increased from 929 to 2611 mg/L, and the proportion of Ca in the residual sludge increased from 22.58 to 46.87 %. Based on the results, when the dosage of Ca concentration was less than 4000 mg/L, the formation of Ca precipitates on the surface of sludge appeared to prevent mass transfer and was the dominant reason for the reduction in methane production and sludge biomass. At higher Ca concentrations (6000-8000 mg/L), the severe inhibition of methane production appeared to be caused by the toxic effect of highly concentrated Ca on sludge as well as mass transfer blockage.

  1. Bioethanol Production by Calcium Alginate-Immobilised St1 Yeast System: Effects of Size of Beads, Ratio and Concentration

    Directory of Open Access Journals (Sweden)

    Masniroszaime Md Zain

    2011-12-01

    Full Text Available Immobilized yeast-cell technology posses several advantages in bioethanol production due to its potential to increase the ethanol yield by eliminating unit process used. Thus, process expenses in cell recovery and reutilization can be minimised. The aim of this study is to investigate the influence of three parameters (substrate concentrations, size of alginate beads and ratio of volume of beads to volume of medium on local isolated yeast (ST1 which immobilized using calcium alginate fermentation system. The most affected ethanol production by calcium alginate-immobilised ST1 yeast system were ratio of volume of the beads to the volume of substrate and concentration of LBS. Highest theoretical yield, 78% was obtained in ST1-alginate beads with the size of beads 0.5cm, ratio volume of beads to the volume of LBS media 0.4 and 150g/l concentration of LBS.ABSTRAK: Teknologi sel yis pegun memiliki beberapa kelebihan dalam penghasilan bioetanol kerana ia berpotensi meningkatkan pengeluaran etanol dengan menyingkirkan unit proses yang digunakan. Maka, proses pembiayaan dalam perolehan sel dan penggunaan semula boleh dikurangkan. Tujuan kajian ini adalah untuk mengkaji pengaruh tiga parameter (kepekatan substrat, saiz manik alginat dan nisbah isipadu manik terhadap isipadu bahantara ke atas sel tempatan terasing (local isolated yeast (ST1 yang dipegun menggunakan sistem penapaian kalsium alginat. Penghasilan etanol yang paling berkesan dengan menggunakan sistem yis ST1 kalsium alginat-pegun adalah dengan kadar nisbah isipadu manik terhadap isipadu substrat dan kepekatan LBS. Kadar hasil teori tertinggi iaitu 78% didapati menerusi manik alginat-ST1 dengan saiz manik 0.5cm, nisbah isipadu 0.4 terhadap perantara LBS dan kepekatan LBS sebanyak 150g/l. Normal 0 false false false EN-US X-NONE X-NONE

  2. Dietary calcium intake, serum copper concentration and bone density in postmenopausal women

    Energy Technology Data Exchange (ETDEWEB)

    Strause, L.; Andon, M.B.; Howard, G.; Smith, K.T.; Saltman, P. (Univ. of California, San Diego, La Jolla (United States) Procter and Gamble Co., Cincinnati, OH (United States))

    1991-03-11

    Data from experimental animal nutrition and animal husbandry indicate that several trace minerals, including copper (Cu) are involved in bone metabolism. In addition, a large body of data suggests that low dietary calcium (Ca) intake is a risk factor for age related bone loss. The authors measured the serum (Cu), dietary Ca intake (dCa) and bone mineral density (BMD) in the spine of 225 postmenopausal women. The median dCa and serum (Cu) were 562 mg/d and 9.73 umoles/L, respectively. Serum (Cu) but, not dCa, was greater in subjects with a history of estrogen therapy (ERT). BMD was higher in subjects with above median dCa and serum (Cu) (group 1) compared to those with below median values (group 2). BMD was intermediate for subjects with either Low serum (Cu):High dCa or High serum (Cu):Low dCa. This relationship was observed in the subject group as a whole, as well as in subgroups partitioned according to history of ERT. Groups 1 and 2 did not differ in basic demographic characteristics such as age, age at menopause, body weight and height. These data support the hypothesis that Ca and Cu nutriture are determinants of skeletal health in postmenopausal women.

  3. Calcium modulates promoter occupancy by the Entamoeba histolytica Ca2+-binding transcription factor URE3-BP.

    Science.gov (United States)

    Gilchrist, Carol A; Leo, Megan; Line, C Genghis; Mann, Barbara J; Petri, William A

    2003-02-14

    The Entamoeba histolytica upstream regulatory element 3-binding protein (URE3-BP) binds to the URE3 sequence of the Gal/GalNAc-inhibitable lectin hgl5 and ferredoxin 1 (fdx) gene promoters. This binding can be inhibited in vitro by addition of calcium. Two EF-hand motifs, which are associated with the ability to bind calcium, are present in the amino acid sequence of URE3-BP. Mutation of the second EF-hand motif in URE3-BP resulted in the loss of calcium inhibition of DNA binding as monitored by electrophoretic mobility shift assay. Chromatin immunoprecipitation assays revealed that URE3-BP was physically bound to the hgl5 and fdx promoters in vivo. Parasite intracellular calcium concentrations were altered by changes in extracellular calcium. Promoter occupancy was lost when intracellular calcium levels were increased by coordinate increases in extracellular calcium. Increased intracellular calcium also resulted in decreased levels of URE3-BP mRNA. Together these results demonstrate that changes in extracellular calcium result in changes in URE3-BP mRNA and in the ability of URE3-BP to bind to URE3-containing promoters. Modulation of URE3-BP by calcium may represent an important mechanism of control of gene expression in E. histolytica.

  4. Relevance of dietary protein concentration and quality as risk factors for the formation of calcium oxalate stones in cats.

    Science.gov (United States)

    Paßlack, Nadine; Burmeier, Hannes; Brenten, Thomas; Neumann, Konrad; Zentek, Jürgen

    2014-01-01

    The role of dietary protein for the development of feline calcium oxalate (CaOx) uroliths has not been conclusively clarified. The present study evaluated the effects of a varying dietary protein concentration and quality on critical indices for the formation of CaOx uroliths. Three diets with a high protein quality (10-11 % greaves meal/diet) and a varying crude protein (CP) concentration (35, 44 and 57 % in DM) were compared. Additionally, the 57 % CP diet was compared with a fourth diet that had a similar CP concentration (55 % in DM), but a lower protein quality (34 % greaves meal/diet). The Ca and oxalate (Ox) concentrations were similar in all diets. A group of eight cats received the same diet at the same time. Each feeding period was divided into a 21 d adaptation period and a 7 d sampling period to collect urine. There were increases in urinary volume, urinary Ca concentrations, renal Ca and Ox excretion and urinary relative supersaturation (RSS) with CaOx with increasing dietary protein concentrations. Urinary pH ranged between 6·34 and 6·66 among all groups, with no unidirectional effect of dietary protein. Lower renal Ca excretion was observed when feeding the diet with the lower protein quality, however, the underlying mechanism needs further evaluation. In conclusion, although the observed higher urinary volume is beneficial, the increase in urinary Ca concentrations, renal Ca and Ox excretion and urinary RSS CaOx associated with a high-protein diet may be critical for the development of CaOx uroliths in cats.

  5. Effects of the Addition of Sodium Alginate and the Concentration of Calcium Chloride on the Properties of Composite Nonwoven Fabrics

    Directory of Open Access Journals (Sweden)

    Lou Ching-Wen

    2016-01-01

    Full Text Available Nonwoven fabrics have merits, and for example, they can be simply and quickly processed with a variety of materials and an easily changeable manufacturing process. This study aims to examine the influences of the addition of sodium alginate (SA and the concentration of calcium chloride (CaCl2 on the properties of the composite nonwoven fabrics. Chitosan (CS micro-particles and SA solution are cross-linked with CaCl2 with various concentrations, combined with farir heat preservative staples (FT/cotton (C nonwoven fabrics, and then freeze-dried to form CS/SA/FT/C composite nonwoven fabrics. Afterwards, physical property tests are performed on the resulting composite nonwoven fabrics to determine their properties as related to various concentrations of CaCl2. The addition of SA decreases the water vapor permeability of FT/C nonwoven fabrics by 15 %, but the concentrations of CaCl2 do not influence the water vapor permeability. Compared to FT/C nonwoven fabrics, CS/SA/FT/C composite nonwoven fabrics have significantly lower water absorbency and water vapor permeability, but a greater stiffness.

  6. Morphological characterization of calli of Eucalyptus urophylla S. T. Blake subjected to concentrations of boron and calcium

    Directory of Open Access Journals (Sweden)

    Raquel Trevizam

    2011-06-01

    Full Text Available This study aimed to evaluate the effect of B and Ca concentrations on morphological responses and size of calli in Eucalyptus urophylla. Calli were obtained from the mid portion of hypocotyls removed from in vitro germinated seedlings. The callus structures were cultivated for 21 and 31 days, being kept in a modified N7 medium with concentrations of B (0; 25; 50; 100 and 200 µM H3BO3 and Ca (0; 3.75; 7.5; 11.25 and 15 mM CaCl2.2H2O. Size of calli, presence of roots, friability, viscosity, presence of globular structures on the surface and presence of pigments were analyzed. Overall, the shorter culture period (21 days allowed better development of callus structures. The combination of 50 µM H3BO3 with 7.5 mM CaCl2.2H2O at 21 days, and 100 µM H3BO3 with 1.13 mM CaCl2.2H2O at 31 days, provided best results. Rhizogenesis responded differently according to B and Ca concentrations. Simultaneous omission of B and Ca inhibited the rhizogenesis, causing disruption of the callus, favored formation of globular and friable structures, with presence of anthocyanin. High concentrations of calcium promoted root induction in calli.

  7. Human resting extracellular heat shock protein 72 concentration decreases during the initial adaptation to exercise in a hot, humid environment

    Science.gov (United States)

    Marshall, Helen C.; Ferguson, Richard A.; Nimmo, Myra A.

    2006-01-01

    Heat shock protein (Hsp) 72 is a cytosolic protein that also is present in the circulation. Extracellular Hsp72 (eHsp72) is inducible by exercise and is suggested to act as a danger signal to the immune system. The adaptive response of eHsp72 to repeated exercise-heat exposures in humans remains to be determined. An intracellular animal study found a reduced Hsp72 response, with no change in resting levels, during heat stress after a single day of passive heat acclimation. The current study therefore tested whether adaptations in human eHsp72 levels would similarly occur 24 hours after a single exercise-heat exposure. Seven males completed cycle exercise (42.5% V̇O2peak for 2 hours) in a hot, humid environment (38°C, 60% relative humidity) on each of 2 consecutive days. Blood samples were obtained from an antecubital vein before exercise and 0 hours and 22 hours postexercise for the analysis of eHsp72. Exercise-heat stress resulted in enhanced eHsp72, with a similar absolute increase found on both days (day 1: 1.26 ng/mL [0.80 ng/mL]; day 2: 1.29 ng/mL [1.60 ng/mL]). Resting eHsp72 decreased from rest on day 1 to day 2's 22-hour postexercise sample (P < 0.05). It is suggested that the reduction in resting eHsp72 after 2 consecutive exercise-heat exposures is possibly due to an enhanced removal from the circulation, for either immunoregulatory functions, or for improved cellular stress tolerance in this initial, most stressful period of acclimation. PMID:16817318

  8. Importance of calcium in the inotropic effect of hyperosomotic agents, norepinephrine, paired electrical stimulation, and treppe.

    Science.gov (United States)

    Willerson, J T; Crie, J S; Adcock, R C; Templeton, G H; Wildenthal, K

    1975-01-01

    The data obtained from these studies demonstrate that the inotropic effect of hyperosmolar mannitol and sucrose and of paired electrical stimulation is critically influenced by extracellular calcium concentration. The inotropic effect of norepinephrine is not prevented by maximal functional extracellular calcium concentrations. Inhibition of systolic calcium flux at the cell membrane by D600 does not prevent the inotropic effect of hyperosmolar mannitol or of paired electrical stimulation but it does prevent the inotropic effect of hyperosmolar intropic effect of treppe. Thus, intracellular calcium regulation appears to be of major importance in the inotropic effect in isolated cardiac muscle of mannitol and paired pacing while systolic calcium flux at the cell membrane appears to be of major importance in the inotropic effect of treppe.

  9. Approximation of Corrected Calcium Concentrations in Advanced Chronic Kidney Disease Patients with or without Dialysis Therapy

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    Yoshio Kaku

    2015-08-01

    Full Text Available Background: The following calcium (Ca correction formula (Payne is conventionally used for serum Ca estimation: corrected total Ca (TCa (mg/dl = TCa (mg/dl + [4 - albumin (g/dl]; however, it is inapplicable to advanced chronic kidney disease (CKD patients. Methods: 1,922 samples in CKD G4 + G5 patients and 341 samples in CKD G5D patients were collected. Levels of TCa (mg/day, ionized Ca2+ (iCa2+ (mmol/l and other clinical parameters were measured. We assumed the corrected TCa to be equal to eight times the iCa2+ value (measured corrected TCa. We subsequently performed stepwise multiple linear regression analysis using the clinical parameters. Results: The following formula was devised from multiple linear regression analysis. For CKD G4 + G5 patients: approximated corrected TCa (mg/dl = TCa + 0.25 × (4 - albumin + 4 × (7.4 - pH + 0.1 × (6 - P + 0.22. For CKD G5D patients: approximated corrected TCa (mg/dl = TCa + 0.25 × (4 - albumin + 0.1 × (6 - P + 0.05 × (24 - HCO3- + 0.35. Receiver operating characteristic analysis showed the high values of the area under the curve of approximated corrected TCa for the detection of measured corrected TCa ≥8.4 mg/dl and ≤10.4 mg/dl for each CKD sample. Both intraclass correlation coefficients for each CKD sample demonstrated superior agreement using the new formula compared to the previously reported formulas. Conclusion: Compared to other formulas, the approximated corrected TCa values calculated from the new formula for patients with CKD G4 + G5 and CKD G5D demonstrates superior agreement with the measured corrected TCa.

  10. Extracellular magnesium decreases the secretory response of rat peritoneal mast cells to compound 48/80 in vitro

    DEFF Research Database (Denmark)

    Bertelsen, Niels Haldor; Johansen, Torben

    1991-01-01

    Exposure of rat peritoneal mast cells to magnesium in the absence of extracellular calcium resulted in a time- and dose-dependent decrease in the secretory response induced by compound 48/80. The decrease was prevented by a low extracellular concentration of calcium. Furthermore, the decreased...... and the secretory stimulus. A dose-dependent decrease in antigen induced histamine secretion that was reversed by calcium was also observed. Exposure of the mast cells to magnesium for 15 min resulted in a parallel decrease in histamine secretion and in the cellular content of 45Ca2+. These observations suggest...... secretory responsiveness was dose-dependently restored by the addition of calcium to the cells simultaneously with compound 48/80. Preincubation with magnesium also inhibited antigen-induced histamine secretion in a dose-dependent manner. This was reversed by the simultaneous addition of calcium...

  11. The effect on lactic fermentation of concentrating inert material with immobilised cells in a calcium alginate biocatalyser

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    Juan Carlos Serrato

    2010-04-01

    Full Text Available Colombia is one of the world’s main sugarcane cultivating countries but it has not diversified its fermentation industry; a few fermentation industries produce alcohol and yeasts. Lactic acid and its derivatives then become alternatives providing added value to the sugar produced, thus benefiting the regions producing the sugar.This work evaluated the kinetics of lactic acid production using immobilised cells in calcium alginate at different concentrations of inert material. Lactobacillus delbrueckiI was the microorganism used and fermentation broth mainly consisted of sucrose and yeast exact. CSTR reactors were used without pH control. The results suggested that 2% to 3% inert material in the biocatalyst increased cellular retention and diffusiveness, leading to improved conversion and reaction rate.

  12. Comparing Titanium Release from Ceramic Tiles using a waste material characterization test - Influence of Calcium and Organic Matter concentrations

    DEFF Research Database (Denmark)

    Heggelund, Laura Roverskov; Hansen, Steffen Foss; Astrup, Thomas Fruergaard

    2015-01-01

    Nanomaterials are beneficial in the building industry to enhance or add certain features to commonly used materials. One example is the use of nano-titanium dioxide in the surface coating of ceramic tiles, to make the tiles surface self-cleaning. At the end of life stage, ceramic tiles might...... to assess if nano-titanium dioxide coated ceramic tiles are suitable for depositing in a landfill or not. Specifically, we used compliance batch test method, which is a simple test evaluating the release from a solid material to an aqueous media during 24 hrs. If nano-Ti particles are released from solid...... of the organic matter to fully cover the surface of the particles. We evaluated the titanium release from identical ceramic tiles - with and without a nano-titanium dioxide coating - and varied the concentrations of calcium chloride (100-500 mg/l) and humic acid (25-100 mg/l). The titanium release was quantified...

  13. Effects of vitamin D supplementation during pregnancy on neonatal vitamin D and calcium concentrations: a systematic review and meta-analysis.

    Science.gov (United States)

    Yang, Na; Wang, Linlin; Li, Zhixia; Chen, Sen; Li, Nan; Ye, Rongwei

    2015-07-01

    We conducted a meta-analysis to review the effects of vitamin D supplementation during pregnancy on neonatal 25-hydroxyvitamin D (25(OH)D) and calcium concentrations. Randomized controlled trials that supplemented subjects with vitamin D2 or D3 during pregnancy and reported cord blood 25(OH)D or calcium concentrations were included. A random-effect model was used to pool the data. Subgroup analyses were performed to explore the sources of heterogeneity. We searched PubMed, Web of Science, and Cochrane Library for relevant publications. Among 1768 publications identified by our search strategy, 13 studies met our inclusion criteria. Cord blood 25(OH)D concentration was significantly increased by maternal vitamin D supplementation (mean difference, 22.48 nmol/L; 95% confidence interval, 15.90-29.06 nmol/L) with high heterogeneity (I2 = 98.8%, P Vitamin D supplementation during pregnancy can improve cord blood 25(OH)D concentration in women with low 25(OH)D concentration, but does not affect cord blood calcium concentration. Future researches are needed to evaluate the effect of maternal vitamin D supplementation in women with a normal 25(OH)D concentration and explore the combined effects of vitamin D, calcium, and multivitamins. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Effects of relative humidity and root temperature on calcium concentration and tipburn development in lettuce.

    Science.gov (United States)

    Collier, G F; Tibbitts, T W

    1984-03-01

    Growth chamber studies were undertaken with a tipburn-sensitive cultivar of romaine lettuce (Lactuca sativa L. cv. Lobjoits Green Cos) grown under a photosynthetic photon flux density of 320 micromoles s-1 m-2 for 16 hours; light and dark temperatures were 26.0 degrees and 12.5 degrees C, respectively. As the relative humidity (RH) during the light period was decreased from 74% to 51%, growth was retarded, Ca concentration increased, and the onset of tipburn delayed. Decreasing RH during the dark period from 95% to 90% reduced growth and resulted in lower Ca concentrations and earlier tipburn development. Further decreases from 90% to 65% caused no additional change in growth or tipburn response. Root temperatures of 23.5 degrees, compared with 15.0 degrees, slightly increased Ca concentration but induced earlier tipburn development. Ca concentrations were increased and tipburn delayed by humidity conditions which provided large diurnal fluctuations in water potential in the plant and which encouraged root pressure flow during the dark period. Elevated root temperatures did not provide expected increases in Ca accumulation in young leaves.

  15. Effects of artificial enclosure of young lettuce leaves on tipburn incidence and leaf calcium concentration

    Science.gov (United States)

    Barta, D. J.; Tibbitts, T. W.

    1986-01-01

    The young developing leaves of 20-day-old lettuce plants (Lactuca sativa L. 'Buttercrunch') were enclosed by aluminized polyethylene sheaths to decrease transpiration and reduce Ca transport. The plants were grown in recirculating solution culture system using a modified half-strength Hoagland's solution under cool-white fluorescent lamps with a photosynthetic photon flux of 350 micromoles s-1 m-2 in a 16:8-hr (light:dark) period. Air temperature and humidity were 20 degrees C and 65%, respectively. After 4 days of enclosure, 53% of the inner leavers (leaves one to 3 cm in length) were tipburned. After the same period, less than 1% of the inner leaves on control plants were tipburned. The concentration of Ca in enclosed inner leaves was 0.63 mg g-1 dry weight, compared to 1.48 mg g-1 dry weight in inner leaves that were not enclosed. The Ca concentration in transpiring outer leaves of all plants was 9.9 mg g-1 dry weight. The Mg concentration in enclosed inner leaves was 2.25 mg g-1 dry weight, compared to 2.34 mg g-1 dry weight in inner leaves that were not enclosed. This research documents that enclosures of leaves at the growing point, as would occur with normal head development, is sufficient to create a limiting concentration of Ca in the enclosed tissue and encourage tipburn development.

  16. Magnesium regulates intracellular ionized calcium concentration and cell geometry in vascular smooth muscle cells (VSMC)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A.; Cheng, T.P.; Altura, B.M. (State Univ. of New York, Brooklyn (United States))

    1991-03-11

    It has been suggested that the extracellular Mg{sup 2+} may modulate contractility of VSMC by controlling the cellular level of free Ca{sup 2+}. The present studies were designed to determine the effects of (Mg{sup 2+}) on the distribution of intracellular free Ca{sup 2+} using digital imaging fluorescence microscopy of Fura-2 fluorescence of single VSMC cultured from rat aortas. When incubated with HEPES buffer solution containing 1.2mM Mg{sup 2+}, the myocytes are spindle-shaped, and the basal level of (Ca{sup 2+}){sub i} estimated from the ratio (F340/F380) is 96.6 {plus minus} 7.9nM with a heterogeneous distribution. (Mg{sup 2+}){sub o} withdrawal from the incubation medium induces consistently a dramatic increment of (Ca{sup 2+}){sub i} up to 579.6 {plus minus} 39.3nM, about a 5.8-fold elevation compared to control experiments. Similarly, lowering (Mg{sup 2+}){sub o} to 0.3mM (the lowest physiological range) elevates (Ca{sup 2+}){sub i} to the intermediate level of 348.0 {plus minus} 31.5nM. However, the heterogeneous distribution of (Ca{sup 2+}){sub i} is still evident when (Mg{sup 2+}){sub o} is lowered. Simultaneously to the (Ca{sup 2+}){sub i} increments, cell shapes were changed. In contrast, elevation of (Mg{sup 2+}){sub o} to 4.8mM was found to decrease (Ca{sup 2+}){sub i} to 72.0 {plus minus} 4.6nM. Removal of (Ca{sup 2+}){sub o}, however, abolished the increments of (Ca{sup 2+}){sub i} induced by (Mg{sup 2+}){sub o} withdrawal. These results demonstrate that (Mg{sup 2+}){sub o} regulated (Ca{sup 2+}){sub i} and geometry of VSMC, probably through controlling plasma membrane permeability to Ca{sup 2+}.

  17. Moderate extracellular acidification inhibits capsaicin-induced cell death through regulating calcium mobilization, NF-{kappa}B translocation and ROS production in synoviocytes

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Fen; Yang, Shuang; Zhao, Dan; Zhu, Shuyan; Wang, Yuxiang [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China); Li, Junying, E-mail: jyli04@nankai.edu.cn [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer Moderate extracellular acidification regulates intracellular Ca{sup 2+} mobilization. Black-Right-Pointing-Pointer Moderate acidification activates NF-{kappa}B nuclear translocation in synoviocytes. Black-Right-Pointing-Pointer Moderate acidification depresses the ROS production induced by capsaicin. Black-Right-Pointing-Pointer Moderate acidification inhibits capsaicin-caused synoviocyte death. -- Abstract: We previously show the expression of transient receptor potential vanilloid 1 (TRPV1) in primary synoviocytes from collagen-induced arthritis (CIA) rats. Capsaicin and lowered extracellular pH from 7.4 to 5.5 induce cell death through TRPV1-mediated Ca{sup 2+} entry and reactive oxygen species (ROS) production. However, under the pathological condition in rheumatoid arthritis, the synovial fluid is acidified to a moderate level (about pH 6.8). In the present study, we examined the effects of pH 6.8 on the TRPV1-mediated cell death. Our finding is different or even opposite from what was observed at pH 5.5. We found that the moderate extracellular acidification (from pH 7.4 to 6.8) inhibited the capsaicin-induced Ca{sup 2+} entry through attenuating the activity of TRPV1. In the mean time, it triggered a phospholipse C (PLC)-related Ca{sup 2+} release from intracellular stores. The nuclear translocation of NF-{kappa}B was found at pH 6.8, and this also depends on PLC activation. Moreover, the capsaicin-evoked massive ROS production and cell death were depressed at pH 6.8, both of which are dependent on the activation of PLC and NF-{kappa}B. Taken together, these results suggested that the moderate extracellular acidification inhibited the capsaicin-induced synoviocyte death through regulating Ca{sup 2+} mobilization, activating NF-{kappa}B nuclear translocation and depressing ROS production.

  18. The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

    Science.gov (United States)

    Yang, Yuhui; Luo, Wenjing

    2017-01-01

    A calcium phosphate (CaP) coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating's morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10−2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10−3 and 10−4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10−3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future. PMID:28250771

  19. The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

    Directory of Open Access Journals (Sweden)

    Qianyue Sun

    2017-01-01

    Full Text Available A calcium phosphate (CaP coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating’s morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10−2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10−3 and 10−4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10−3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future.

  20. Structural Studies of a Complex Between Endothelial Nitric Oxide Synthase and Calmodulin at Physiological Calcium Concentration.

    Science.gov (United States)

    Piazza, Michael; Dieckmann, Thorsten; Guillemette, Joseph Guy

    2016-10-04

    The small acidic protein Calmodulin (CaM) serves as a Ca(2+) sensor and control element for many enzymes including nitric oxide synthase (NOS) enzymes that play major roles in key physiological and pathological processes. CaM binding causes a conformational change in NOS to allow for the electron transfer between the reductase and oxygenase domains through a process that is thought to be highly dynamic. In this report, NMR spectroscopy was used to determine the solution structure of the endothelial NOS (eNOS) peptide in complex with CaM at the lowest Ca(2+) concentration (225 nM) required for CaM to bind to eNOS and corresponds to a physiological elevated Ca2+ level found in mammalian cells. Under these conditions, the CaM-eNOS complex has a Ca(2+)-replete C-terminal lobe bound the eNOS peptide and a Ca(2+) free N-terminal lobe loosely associated to the eNOS peptide. With increasing Ca(2+) concentration, the binding of Ca(2+) by the N-lobe of CaM results in a stronger interaction with the C-terminal region of the eNOS peptide and increased α-helical structure of the peptide that may be part of the mechanism resulting in electron transfer from the FMN to the heme in the oxygenase domain of the enzyme. SPR studies performed under the same conditions show Ca(2+) concentration dependent binding kinetics were consistent with the NMR structural results. This investigation shows that structural studies performed under more physiological relevant conditions provide information on subtle changes in structure that may not be apparent when experiments are performed in excess Ca(2+) concentrations.

  1. Auranofin, an Anti-Rheumatic Gold Compound, Modulates Apoptosis by Elevating the Intracellular Calcium Concentration ([Ca2+]i in MCF-7 Breast Cancer Cells

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    Elizabeth Varghese

    2014-11-01

    Full Text Available Auranofin, a transition metal complex is used for the treatment of rheumatoid arthritis but is also an effective anti-cancer drug. We investigate the effects of Auranofin in inducing cell death by apoptosis and whether these changes are correlated to changes of intracellular calcium concentration ([Ca2+]i in breast cancer cells (MCF-7. Cytotoxicity of Auranofin was evaluated using MTS assay and the Trypan blue dye exclusion method. With fluorescent dyes SR-FLICA and 7-AAD apoptotic death and necrotic death were differentiated by Flow cytometry. A concentration dependent decrease in the viability occurred and cells were shifted to the apoptotic phase. Intracellular calcium ([Ca2+]i was recorded using florescence microscopy and a calcium sensitive dye (Fluo-4 AM with a strong negative correlation (r = −0.713 to viability. Pharmacological modulators 2-APB (50 μM, Nimodipine (10 μM, Caffeine (10 mM, SKF 96365(20 μM were used to modify calcium entry and release. Auranofin induced a sustained increase of [Ca2+]i in a concentration and time dependent manner. The use of different blockers of calcium channels did not reveal the source for the rise of [Ca2+]i. Overall, elevation of [Ca2+]i by Auranofin might be crucial for triggering Ca2+-dependent apoptotic pathways. Therefore, in anti-cancer therapy, modulating [Ca2+]i should be considered as a crucial factor for the induction of cell death in cancer cells.

  2. Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

    Directory of Open Access Journals (Sweden)

    Silva Raul F

    2012-07-01

    Full Text Available Abstract Background The clinical use of autologous platelet concentrates (also known as platelet-rich plasma on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1 to describe and compare the cellular population in whole blood, lower fraction (A and upper fraction (B of platelet concentrates, 2 to measure and compare the transforming growth factor beta 1 (TGF-β1 concentration in plasma and both platelet concentrates after be activated with calcium gluconate or batroxobin plus calcium gluconate and, 3 to determine correlations between cell counts in platelet concentrates and concentrations of TGF-β1. Blood samples were taken from 16 dogs for complete blood count, plasma collection and platelet concentrates preparation. The platelet concentrates (PC were arbitrarily divided into two fractions, specifically, PC-A (lower fraction and PC-B (upper fraction. The Platelet concentrates were analyzed by hemogram. After activated with calcium gluconate or batroxobin plus calcium gluconate, TGF-β1 concentration was determined in supernatants of platelet concentrates and plasma. Results There were differences statistically significant (P 1 concentration between whole blood, plasma and both platelet concentrates. A significant correlation was found between the number of platelets in both platelet concentrates and TGF-β1 concentration. Platelet collection efficiency was 46.34% and 28.16% for PC-A and PC-B, respectively. TGF-β1 concentration efficiency for PC activated with calcium gluconate was 47.75% and 31.77%, for PC-A and PC-B, respectively. PC activated with batroxobin plus CG showed 46.87% and 32.24% for PC-A and PC-B, respectively. Conclusions The methodology used in this study allows the concentration of a number of platelets and TGF-β1 that might be acceptable for a biological effect for clinical or experimental use as a

  3. Influence of Parathyroidectomy on Bone Calcium Concentration: Evaluation with Spectral CT in Patients with Secondary Hyperparathyroidism Undergoing Hemodialysis-A Prospective Feasibility Study.

    Science.gov (United States)

    Ma, Qiang; Yang, Zhenghan; Han, Xue; Liu, Fen; Su, Dechun; Xing, Haidong

    2017-02-07

    Purpose To use spectral computed tomography (CT) to evaluate the influence of parathyroidectomy (PTX) on calcium concentration in trabecular bone and cortical bone in patients undergoing hemodialysis with secondary hyperparathyroidism. Materials and Methods This study was performed with institutional review board approval. Written consent was obtained from each patient. Thirty-eight men (mean age ± standard deviation, 55.69 years ± 8.05; range, 42-72 years) undergoing maintenance hemodialysis who underwent PTX and 40 patients (mean age, 56.71 years ± 9.53; range, 45-74 years) who did not undergo PTX received prospective follow-up for 2 years. Bone calcium concentration was measured in the cortical compartment of the bilateral proximal femur and the medullary compartment of the lumbar vertebral bodies (L1 through L3) on the basis of calcium-based material decomposition images of a spectral CT examination. The differences between baseline and end-of-study PTX parameters were analyzed with the paired Student t test. Results For patients who underwent PTX, mean cortical bone calcium concentration increased from 220.69 mg/cm(3) ± 25.79 to 257.43 mg/cm(3) ± 25.46 (t = 8.546, P < .001), whereas medullary bone calcium concentration decreased from 64.75 mg/cm(3) ± 15.07 to 61.42 mg/cm(3) ± 15.77 (t = 22.293, P < .001) from baseline to follow-up. In patients who did not undergo PTX, mean cortical bone calcium concentration decreased from 296.08 mg/cm(3) ± 36.35 to 258.35 mg/cm(3) ± 31.46 (t = 7.420, P < .001), but medullary bone calcium concentration increased from 61.13 mg/cm(3) ± 13.85 to 62.94 mg/cm(3) ± 14.80 (t = 2.370, P = .023) from baseline to follow-up. Conclusion During the course of chronic renal failure, different bone elements involve various pathologic changes. PTX could reverse long-term cortical bone loss reflected in calcium concentration measured with spectral CT; however, it could induce medullary bone loss. (©) RSNA, 2017 Online supplemental

  4. Calcium, amylase, glucose, total protein concentrations, flow rate, pH and buffering capacity of saliva in patients undergoing orthodontic treatment with fixed appliances

    Directory of Open Access Journals (Sweden)

    Hellen Soares Teixeira

    2012-04-01

    Full Text Available OBJECTIVE: To evaluate qualitative and quantitative changes in the saliva of individuals undergoing orthodontic treatment with fixed appliances. METHODS: Salivary samples were collected from 50 individuals divided in two groups: Experimental Group - patients with fixed orthodontic appliances (n=25; and Control Group - subjects with no orthodontic appliances (n=25. Salivary flow rate, pH, buffering capacity, amylase activity, concentrations of total proteins, calcium and glucose were measured in all salivary samples. RESULTS: There was a reduction in salivary pH and buffering capacity and an increase in the concentration of calcium ions in the experimental group (p<0.05; there was also an increase in glucose, amylase and protein concentrations in the saliva of the Experimental Group, but the differences were insignificant. There was insignificant correlation between calcium ion concentration and salivary flow or between buffering capacity and salivary flow. CONCLUSION: The saliva of individuals with fixed orthodontic appliances had lower pH, buffering capacity and calcium concentration than that of individuals without any type of orthodontic appliance. These oral changes are enough to cause tooth demineralization. Patients with orthodontic appliances should adopt additional oral hygiene procedures.

  5. Elevated extracellular calcium increases fibroblast growth factor-2 gene and protein expression levels via a cAMP/PKA dependent pathway in cementoblasts.

    Science.gov (United States)

    Kanaya, Sousuke; Nemoto, Eiji; Ebe, Yukari; Somerman, Martha J; Shimauchi, Hidetoshi

    2010-09-01

    Cementoblasts, tooth root lining cells, are responsible for laying down cementum on the root surface, a process that is indispensable for establishing a functional periodontal ligament. Cementoblasts share phenotypical features with osteoblasts. Elevated levels of extracellular Ca(2+) have been implicated in osteogenesis by stimulating the proliferation and differentiation of osteoblasts; however, the role of extracellular Ca(2+) signaling in cementogenesis has not been examined. Using RT-PCR, we found that elevated levels of extracellular Ca(2+) increase fibroblast growth factor (FGF)-2 gene expression with a peak at 6h. Pretreatment with a protein kinase A (PKA) inhibitor, H89, or an adenylate cyclase inhibitor, MDL-12,330A, inhibited Ca(2+)-stimulated Fgf-2 expression. In contrast, pretreatment with the protein kinase C (PKC) inhibitor GF-109203X or the phospholipase C (PLC) inhibitor U73122 did not affect the expression of Fgf-2 transcripts, suggesting that the increase in Fgf-2 expression was dependent on the PKA but not the PLC/PKC signaling pathway. Treatment with an activator of adenylate cyclase, forskolin, or a cell-permeable analog of cAMP, 8-Br-cAMP, enhanced Ca(2+)-stimulated Fgf-2 expression, but a single treatment with forskolin or 8-Br-cAMP did not, suggesting that cAMP generation is indispensable but not sufficient for Ca(2+)-stimulated FGF2 expression. Next, we examined the cation specificity of the putative receptor and showed that treatment with trivalent/divalent inorganic ions, Ca(2+), Gd(3+), Sr(2+), or Al(3+), caused a dose-dependent increase in Fgf-2 mRNA levels in a cAMP-dependent fashion, whereas Mg(2+) and the organic ions neomycin and spermine had no effect on Fgf-2 gene expression levels. These findings suggest that an extracellular Ca(2+)-sensing mechanism is present in cementoblasts and its activation leads to FGF-2 stimulation in a cAMP/PKA dependent fashion. Understanding the pathway regulating key genes involved in modulating the

  6. Grape seed extract triggers apoptosis in Caco-2 human colon cancer cells through reactive oxygen species and calcium increase: extracellular signal-regulated kinase involvement.

    Science.gov (United States)

    Dinicola, Simona; Mariggiò, Maria Addolorata; Morabito, Caterina; Guarnieri, Simone; Cucina, Alessandra; Pasqualato, Alessia; D'Anselmi, Fabrizio; Proietti, Sara; Coluccia, Pierpaolo; Bizzarri, Mariano

    2013-09-14

    Grape seed extract (GSE) from Italia, Palieri and Red Globe cultivars inhibits cell growth and induces apoptosis in Caco-2 human colon cancer cells in a dose-dependent manner. In order to investigate the mechanism(s) supporting the apoptotic process, we analysed reactive oxygen species (ROS) production, intracellular Ca2+ handling and extracellular signal-regulated kinase (ERK) activation. Upon exposure to GSE, ROS and intracellular Ca2+ levels increased in Caco-2 cells, concomitantly with ERK inactivation. As ERK activity is thought to be essential for promoting survival pathways, inhibition of this kinase is likely to play a relevant role in GSE-mediated anticancer effects. Indeed, pretreatment with N-acetyl cysteine, a ROS scavenger, reversed GSE-induced apoptosis, and promoted ERK phosphorylation. This effect was strengthened by ethylene glycol tetraacetic acid-mediated inhibition of extracellular Ca2+ influx. ROS and Ca2+ influx inhibition, in turn, increased ERK phosphorylation, and hence almost entirely suppressed GSE-mediated apoptosis. These data suggested that GSE triggers a previously unrecognised ERK-based mechanism, involving both ROS production and intracellular Ca2+ increase, eventually leading to apoptosis in cancer cells.

  7. A randomized, double-blind, placebo-controlled trial of calcium acetate on serum phosphorus concentrations in patients with advanced non-dialysis-dependent chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Ho Chiang-Hong

    2011-02-01

    Full Text Available Abstract Background Hyperphosphatemia in patients with chronic kidney disease (CKD contributes to secondary hyperparathyroidism, soft tissue calcification, and increased mortality risk. This trial was conducted to examine the efficacy and safety of calcium acetate in controlling serum phosphorus in pre-dialysis patients with CKD. Methods In this randomized, double-blind, placebo-controlled trial, 110 nondialyzed patients from 34 sites with estimated GFR 2 and serum phosphorus > 4.5 mg/dL were randomized to calcium acetate or placebo for 12 weeks. The dose of study drugs was titrated to achieve target serum phosphorus of 2.7-4.5 mg/dL. Serum phosphorus, calcium, iPTH, bicarbonate and serum albumin were measured at baseline and every 2 weeks for the 12 week study period. The primary efficacy endpoint was serum phosphorus at 12 weeks. Secondary endpoints were to measure serum calcium and intact parathyroid hormone (iPTH levels. Results At 12 weeks, serum phosphorus concentration was significantly lower in the calcium acetate group compared to the placebo group (4.4 ± 1.2 mg/dL vs. 5.1 ± 1.4 mg/dL; p = 0.04. The albumin-adjusted serum calcium concentration was significantly higher (9.5 ± 0.8 vs. 8.8 ± 0.8; p p Conclusions In CKD patients not yet on dialysis, calcium acetate was effective in reducing serum phosphorus and iPTH over a 12 week period. Trial Registration www.clinicaltrials.gov NCT00211978.

  8. Relationship between tap water hardness, magnesium, and calcium concentration and mortality due to ischemic heart disease or stroke in the Netherlands

    NARCIS (Netherlands)

    Leurs, L.J.; Schouten, L.J.; Mons, M.N.; Goldbohm, R.A.; Brandt, P.A. van den

    2010-01-01

    BACKGROUND: Conflicting results on the relationship between the hardness of drinking water and mortality related to ischemic heart disease (IHD) or stroke have been reported. OBJECTIVES: We investigated the possible association between tap water calcium or magnesium concentration and total hardness

  9. Simultaneous determination of free calcium, magnesium, sodium and potassium ion concentrations in simulated milk ultrafiltrate and reconstituted skim milk using the Donnan Membrane Technique

    NARCIS (Netherlands)

    Gao, R.; Temminghoff, E.J.M.; Leeuwen, van H.P.; Valenberg, van H.J.F.; Eisner, M.D.; Boekel, van M.A.J.S.

    2009-01-01

    This study focused on determination of free Ca2+, Mg2+, Na+ and K+ concentrations in a series of CaCl2 solutions, simulated milk ultrafiltrate and reconstituted skim milk using a recently developed Donnan Membrane Technique (DMT). A calcium ion selective electrode was used to compare the DMT results

  10. Relationship between tap water hardness, magnesium, and calcium concentration and mortality due to ischemic heart disease or stroke in the Netherlands

    NARCIS (Netherlands)

    Leurs, L.J.; Schouten, L.J.; Mons, M.N.; Goldbohm, R.A.; Brandt, P.A. van den

    2010-01-01

    BACKGROUND: Conflicting results on the relationship between the hardness of drinking water and mortality related to ischemic heart disease (IHD) or stroke have been reported. OBJECTIVES: We investigated the possible association between tap water calcium or magnesium concentration and total hardness

  11. Association of dental and skeletal fluorosis with calcium intake and serum vitamin D concentration in adolescents from a region endemic for fluorosis

    Science.gov (United States)

    Patel, Prerna P.; Patel, Pinal A.; Zulf, M. Mughal; Yagnik, Bhrugu; Kajale, Neha; Mandlik, Rubina; Khadilkar, Vaman; Chiplonkar, Shashi A.; Phanse, Supriya; Patwardhan, Vivek; Joshi, Priscilla; Patel, Ashish; Khadilkar, Anuradha V.

    2017-01-01

    Context: Fluorosis is controlled by the duration of fluoride exposure and calcium and Vitamin D nutrition status. Aim: To examine (a) prevalence of dental and skeletal fluorosis in adolescents from upper, middle, and lower socioeconomic strata (SES) and (b) association of fluorosis with calcium intake and Vitamin D status. Settings and Design: A cross-sectional study conducted in 10–13.9 years apparently healthy adolescents (n = 90), from different SES of Patan (Gujarat, India). Materials and Methods: Dental fluorosis was graded as mild, moderate, and severe. Radiographs of the right hand and wrist were examined and graded. Serum 25 hydroxyvitamin D3 (25OHD) and parathyroid hormone concentrations were measured. Diet was recorded (24 h recall) and calcium intake was computed (C-diet V-2.1, 2013, Xenios Technologies Pvt. Ltd). Statistical Analysis: Generalized linear model was used to analyze relationships between fluorosis, SES, serum 25OHD concentration, and calcium intake. Results: Fluorosis was predominant in lower SES (17% had both dental and radiological features whereas 73% had dental fluorosis); no skeletal deformities were observed. Mean 25OHD concentrations and dietary calcium were 26.3 ± 4.9, 23.4 ± 4.7, and 18.6 ± 4 ng/ml and 441.2 ± 227.6, 484.3 ± 160.9, and 749.2 ± 245.4 mg/day, respectively, for lower, middle, and upper SES (P < 0.05). Fluorosis and SES showed a significant association (exponential β = 2.5, P = 0.01) as compared to upper SES, middle SES adolescents were at 1.3 times while lower SES adolescents were at 2.5 times higher risk. Serum 25OHD concentrations (P = 0.937) and dietary calcium intake (P = 0.825) did not show a significant association with fluorosis. Conclusion: Fluorosis was more common in lower SES adolescents, probably due to the lack of access to bottled water. Relatively adequate calcium intake and serum 25OHD concentrations may have increased the efficiency of dietary calcium absorption, thus preventing severe

  12. Association of dental and skeletal fluorosis with calcium intake and serum vitamin D concentration in adolescents from a region endemic for fluorosis

    Directory of Open Access Journals (Sweden)

    Prerna P Patel

    2017-01-01

    Full Text Available Context: Fluorosis is controlled by the duration of fluoride exposure and calcium and Vitamin D nutrition status. Aim: To examine (a prevalence of dental and skeletal fluorosis in adolescents from upper, middle, and lower socioeconomic strata (SES and (b association of fluorosis with calcium intake and Vitamin D status. Settings and Design: A cross-sectional study conducted in 10–13.9 years apparently healthy adolescents (n = 90, from different SES of Patan (Gujarat, India. Materials and Methods: Dental fluorosis was graded as mild, moderate, and severe. Radiographs of the right hand and wrist were examined and graded. Serum 25 hydroxyvitamin D3 (25OHD and parathyroid hormone concentrations were measured. Diet was recorded (24 h recall and calcium intake was computed (C-diet V-2.1, 2013, Xenios Technologies Pvt. Ltd. Statistical Analysis: Generalized linear model was used to analyze relationships between fluorosis, SES, serum 25OHD concentration, and calcium intake. Results: Fluorosis was predominant in lower SES (17% had both dental and radiological features whereas 73% had dental fluorosis; no skeletal deformities were observed. Mean 25OHD concentrations and dietary calcium were 26.3 ± 4.9, 23.4 ± 4.7, and 18.6 ± 4 ng/ml and 441.2 ± 227.6, 484.3 ± 160.9, and 749.2 ± 245.4 mg/day, respectively, for lower, middle, and upper SES (P < 0.05. Fluorosis and SES showed a significant association (exponential β = 2.5, P = 0.01 as compared to upper SES, middle SES adolescents were at 1.3 times while lower SES adolescents were at 2.5 times higher risk. Serum 25OHD concentrations (P = 0.937 and dietary calcium intake (P = 0.825 did not show a significant association with fluorosis. Conclusion: Fluorosis was more common in lower SES adolescents, probably due to the lack of access to bottled water. Relatively adequate calcium intake and serum 25OHD concentrations may have increased the efficiency of dietary calcium absorption, thus preventing severe

  13. Bone mass and breast milk calcium concentration are associated with vitamin D receptor gene polymorphisms in adolescent mothers.

    Science.gov (United States)

    Bezerra, Flávia F; Cabello, Giselda M K; Mendonça, Laura M C; Donangelo, Carmen M

    2008-02-01

    Lactation-associated bone loss has been reported in adolescent mothers. Polymorphisms in the vitamin D receptor (VDR) gene may contribute to differences in the physiologic skeletal response to lactation in these mothers. We evaluated the influence of VDR gene polymorphisms ApaI, BsmI, and TaqI on bone mass, bone and calcium-related hormones, and breast milk calcium of lactating adolescents with habitually low calcium intake. Total body bone mineral content (TBMC), total body bone mineral density (TBMD), lumbar spine BMD (LSBMD), serum hormones [intact parathyroid hormone (iPTH), 25-hydroxyvitamin D, insulin-like growth factor-I (IGF1), prolactin, and estradiol), and breast milk calcium were measured in 40 lactating Brazilian adolescents (15-18 y), and compared by VDR genotype subgroups after adjustment for calcium intake and postmenarcheal and lactational periods. TBMD and LSBMD Z scores were -0.55 +/- 1.01 and -1.15 +/- 1.48, respectively. LSBMD was higher (21%; P milk calcium and serum iPTH were higher (24 and 80%, respectively; P milk calcium are significantly associated with VDR genotypes in lactating Brazilian adolescents. Those with aa and tt genotypes had a better bone status and those with bb genotype had greater breast milk calcium.

  14. Changes in intracellular calcium concentration influence beat-to-beat variability of action potential duration in canine ventricular myocytes.

    Science.gov (United States)

    Kistamas, K; Szentandrassy, N; Hegyi, B; Vaczi, K; Ruzsnavszky, F; Horvath, B; Banyasz, T; Nanasi, P P; Magyar, J

    2015-02-01

    The aim of the present work was to study the influence of changes in intracellular calcium concentration ([Ca(2+)]i) on beat-to-beat variability (short term variability, SV) of action potential duration (APD) in isolated canine ventricular cardiomyocytes. Series of action potentials were recorded from enzymatically isolated canine ventricular cells using conventional microelectrode technique. Drug effects on SV were evaluated as relative SV changes determined by plotting the drug-induced changes in SV against corresponding changes in APD and comparing these data to the exponential SV-APD function obtained with inward and outward current injections. Exposure of myocytes to the Ca(2+) chelator BAPTA-AM (5 μM) decreased, while Ca(2+) ionophore A23187 (1 μM) increased the magnitude of relative SV. Both effects were primarily due to the concomitant changes in APD. Relative SV was reduced by BAPTA-AM under various experimental conditions including pretreatment with veratridine, BAY K8644, dofetilide or E-4031. Contribution of transient changes of [Ca(2+)]i due to Ca(2+) released from the sarcoplasmic reticulum (SR) was studied using 10 μM ryanodine and 1 μM cyclopiazonic acid: relative SV was reduced by both agents. Inhibition of the Na(+)-Ca(2+) exchanger by 1 μM SEA0400 increased relative SV. It is concluded that elevation of [Ca(2+)]i increases relative SV significantly. More importantly, Ca(2+) released from the SR is an important component of this effect.

  15. Microstructural, textural, and sensory characteristics of probiotic yogurts fortified with sodium calcium caseinate or whey protein concentrate.

    Science.gov (United States)

    Akalın, A S; Unal, G; Dinkci, N; Hayaloglu, A A

    2012-07-01

    The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety.

  16. Relation between force and calcium ion concentration in different fibre types of the iliofibularis muscle of Xenopus laevis.

    Science.gov (United States)

    Stienen, G J; van der Laarse, W J; Diegenbach, P C; Elzinga, G

    1987-01-01

    Calcium activated isometric force was measured in segments of single muscle fibres of the iliofibularis muscle of Xenopus laevis skinned by freeze-drying. A subdivision in five different fibre types was made, based on the location of the fibres inside the muscle, fibre diameter and a quantitative histochemical assay for succinate dehydrogenase activity. The Ca2+ sensitivity was characterized by fitting a Hill curve to the force levels reached at different Ca2+ concentrations. The parameter n of this equation indicates the steepness and pK the midpoint of this force-pCa relation. A considerable variability in the Ca2+ sensitivity characteristics was found between different fibres. The parameter n varied between 1.1 and 4.2 while pK varied between 5.5 and 6.6. The distribution of the data indicates the presence of three groups with different Ca2+ sensitivity; a group of fibres with low Ca2+ sensitivity but with considerable variation of the steepness of the Ca2+ sensitivity curves (type 1 fibres), an intermediate group (type 2, 3 and 4 fibres) with also considerable variation in steepness of the Ca2+ sensitivity curves, in which the lowest values for n are found in type 3 and 4 fibres and a group with high Ca2+ sensitivity and low n containing at least one tonic (type 5) fibre. At sub-saturating Ca2+ concentrations occasionally a transient decrease of the rate of force development was found which resembled the force oscillation reported for some mammalian muscle fibres.

  17. Purinergically induced membrane fluidization in ciliary cells: characterization and control by calcium and membrane potential.

    Science.gov (United States)

    Alfahel, E; Korngreen, A; Parola, A H; Priel, Z

    1996-02-01

    To examine the role of membrane dynamics in transmembrane signal transduction, we studied changes in membrane fluidity in mucociliary tissues from frog palate and esophagus epithelia stimulated by extracellular ATP. Micromolar concentrations of ATP induced strong changes in fluorescence polarization, possibly indicating membrane fluidization. This effect was dosage dependent, reaching a maximum at 10-microM ATP. It was dependent on the presence of extracellular Ca2+ (or Mg2+), though it was insensitive to inhibitors of voltage-gated calcium channels. It was inhibited by thapsigargin and by ionomycin (at low extracellular Ca2+ concentration), both of which deplete Ca2+ stores. It was inhibited by the calcium-activated potassium channel inhibitors quinidine, charybdotoxin, and apamine and was reduced considerably by replacement of extracellular Na+ with K+. Hyperpolarization, or depolarization, of the mucociliary membrane induced membrane fluidization. The degree of membrane fluidization depended on the degree of hyperpolarization or depolarization of the ciliary membrane potential and was considerably lower than the effect induced by extracellular ATP. These results indicate that appreciable membrane fluidization induced by extracellular ATP depends both on an increase in intracellular Ca2+, mainly from its internal stores, and on hyperpolarization of the membrane. Calcium-dependent potassium channels couple the two effects. In light of recent results on the enhancement of ciliary beat frequency, it would appear that extracellular ATP-induced changes both in ciliary beat frequency and in membrane fluidity are triggered by similar signal transduction pathways.

  18. Calcium wave of tubuloglomerular feedback.

    Science.gov (United States)

    Peti-Peterdi, János

    2006-08-01

    ATP release from macula densa (MD) cells into the interstitium of the juxtaglomerular (JG) apparatus (JGA) is an integral component of the tubuloglomerular feedback (TGF) mechanism that controls the glomerular filtration rate. Because the cells of the JGA express a number of calcium-coupled purinergic receptors, these studies tested the hypothesis that TGF activation triggers a calcium wave that spreads from the MD toward distant cells of the JGA and glomerulus. Ratiometric calcium imaging of in vitro microperfused isolated JGA-glomerulus complex dissected from rabbits was performed with fluo-4/fura red and confocal fluorescence microscopy. Activation of TGF by increasing tubular flow rate at the MD rapidly produced a significant elevation in intracellular Ca(2+) concentration ([Ca(2+)](i)) in extraglomerular mesangial cells (by 187.6 +/- 45.1 nM) and JG renin granular cells (by 281.4 +/- 66.6 nM). Subsequently, cell-to-cell propagation of the calcium signal at a rate of 12.6 +/- 1.1 microm/s was observed upstream toward proximal segments of the afferent arteriole and adjacent glomeruli, as well as toward intraglomerular elements including the most distant podocytes (5.9 +/- 0.4 microm/s). The same calcium wave was observed in nonperfusing glomeruli, causing vasoconstriction and contractions of the glomerular tuft. Gap junction uncoupling, an ATP scavenger enzyme cocktail, and pharmacological inhibition of P(2) purinergic receptors, but not adenosine A(1) receptor blockade, abolished the changes in [Ca(2+)](i) and propagation of the calcium wave. These studies provided evidence that both gap junctional communication and extracellular ATP are integral components of the TGF calcium wave.

  19. Influence of the calcium concentration in the presence of organic phosphorus on the physicochemical compatibility and stability of all-in-one admixtures for neonatal use

    Directory of Open Access Journals (Sweden)

    de Sousa Valeria

    2009-10-01

    Full Text Available Abstract Background Preterm infants need high amounts of calcium and phosphorus for bone mineralization, which is difficult to obtain with parenteral feeding due to the low solubility of these salts. The objective of this study was to evaluate the physicochemical compatibility of high concentrations of calcium associated with organic phosphate and its influence on the stability of AIO admixtures for neonatal use. Methods Three TPN admixture formulas were prepared in multilayered bags. The calcium content of the admixtures was adjusted to 0, 46.5 or 93 mg/100 ml in the presence of a fixed organic phosphate concentration as well as lipids, amino acids, inorganic salts, glucose, vitamins and oligoelements at pH 5.5. Each admixture was stored at 4°C, 25°C or 37°C and evaluated over a period of 7 days. The physicochemical stability parameters evaluated were visual aspect, pH, sterility, osmolality, peroxide formation, precipitation, and the size of lipid globules. Results Color alterations occurred from the first day on, and reversible lipid film formation from the third day of study for the admixtures stored at 25°C and 37°C. According to the parameters evaluated, the admixtures were stable at 4°C; and none of them presented precipitated particles due to calcium/phosphate incompatibility or lipid globules larger than 5 μm, which is the main parameter currently used to evaluate lipid emulsion stability. The admixtures maintained low peroxide levels and osmolarity was appropriate for parenteral administration. Conclusion The total calcium and calcium/phosphorus ratios studied appeared not to influence the physicochemical compatibility and stability of AIO admixtures.

  20. Study on Producing Magnesium Hydroxide by Concentrated Seawater- calcium Method%浓海水-钙法制取氢氧化镁工艺研究

    Institute of Scientific and Technical Information of China (English)

    高春娟; 张雨山; 黄西平; 蔡荣华

    2011-01-01

    Calcium method ( light burned dolomite and lime) producing magnesium hydroxide from concentrated seawater of desalination plant has advantages of low producing cost and rich resources. However, magnesium hydroxide produced by traditional calcium method has high -content impurities and low purity. Based on patent technology developing independently, the technology of concentrated seawater - calcium method producing magnesium hydroxide was improved in raw material pretreatment, magnesium hydroxide synthesis, calcium sulfate precipitation and precipitate washing. The results showed that the quantities of magnesium hydroxide produced by new technology accord with industry standard, while the content of calcium oxide is reduced significantly. Meanwhile, high quantity byproduct calcium sulfate was obtained.%浓海水一钙法(轻烧白云石、石灰)制取氢氧化镁具有生产成本低、资源丰富的优势,但传统钙法生产的氢氧化镁存在杂质含量高、产品纯度低等缺陷.文章以自主研发的专利技术为基础,从原料预处理、氢氧化镁合成、硫酸钙沉降、沉淀洗涤等方面对浓海水-钙法制取氢氧化镁的工艺进行改进.结果表明,采用改进后的工艺制备的氢氧化镁质量符合行业标准要求,氧化钙含量明显降低,同时得到高质量的副产硫酸钙.

  1. Activity-Dependent Changes in Extracellular Ca2+ and K+ Reveal Pacemakers in the Spinal Locomotor-Related Network

    OpenAIRE

    Brocard, Frédéric; Shevtsova, Natalia A.; Bouhadfane, Mouloud; Tazerart, Sabrina; Heinemann, Uwe; Rybak, Ilya A.; Vinay, Laurent

    2013-01-01

    Changes in the extracellular ionic concentrations occur as a natural consequence of firing activity in large populations of neurons. The extent to which these changes alter the properties of individual neurons and the operation of neuronal networks remains unknown. Here, we show that the locomotor-like activity in the isolated neonatal rodent spinal cord reduces the extracellular calcium ([Ca2+]o) to 0.9 mM and increases the extracellular potassium ([K+]o) to 6 mM. Such changes in [Ca2+]o and...

  2. Auranofin, an Anti-Rheumatic Gold Compound, Modulates Apoptosis by Elevating the Intracellular Calcium Concentration ([Ca{sup 2+}]{sub i}) in MCF-7 Breast Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Varghese, Elizabeth; Büsselberg, Dietrich, E-mail: dib2015@qatar-med.cornell.edu [Weil Cornell Medical College in Qatar, Qatar Foundation-Education City, P.O. Box 24144 Doha (Qatar)

    2014-11-06

    Auranofin, a transition metal complex is used for the treatment of rheumatoid arthritis but is also an effective anti-cancer drug. We investigate the effects of Auranofin in inducing cell death by apoptosis and whether these changes are correlated to changes of intracellular calcium concentration ([Ca{sup 2+}]{sub i}) in breast cancer cells (MCF-7). Cytotoxicity of Auranofin was evaluated using MTS assay and the Trypan blue dye exclusion method. With fluorescent dyes SR-FLICA and 7-AAD apoptotic death and necrotic death were differentiated by Flow cytometry. A concentration dependent decrease in the viability occurred and cells were shifted to the apoptotic phase. Intracellular calcium ([Ca{sup 2+}]{sub i}) was recorded using florescence microscopy and a calcium sensitive dye (Fluo-4 AM) with a strong negative correlation (r = −0.713) to viability. Pharmacological modulators 2-APB (50 μM), Nimodipine (10 μM), Caffeine (10 mM), SKF 96365(20 μM) were used to modify calcium entry and release. Auranofin induced a sustained increase of [Ca{sup 2+}]{sub i} in a concentration and time dependent manner. The use of different blockers of calcium channels did not reveal the source for the rise of [Ca{sup 2+}]{sub i}. Overall, elevation of [Ca{sup 2+}]{sub i} by Auranofin might be crucial for triggering Ca{sup 2+}-dependent apoptotic pathways. Therefore, in anti-cancer therapy, modulating [Ca{sup 2+}]{sub i} should be considered as a crucial factor for the induction of cell death in cancer cells.

  3. Regulation of BMP2-induced intracellular calcium increases in osteoblasts.

    Science.gov (United States)

    Xu, Wenfeng; Liu, Bo; Liu, Xue; Chiang, Martin Y M; Li, Bo; Xu, Zichen; Liao, Xiaoling

    2016-10-01

    Although bone morphogenetic protein-2 (BMP2) is a well-characterized regulator that stimulates osteoblast differentiation, little is known about how it regulates intracellular Ca(2+) signaling. In this study, intracellular Ca(2+) concentration ([Ca(2+) ]i ) upon BMP2 application, focal adhesion kinase (FAK) and Src activities were measured in the MC3T3-E1 osteoblast cell line using fluorescence resonance energy transfer-based biosensors. Increase in [Ca(2+) ]i , FAK, and Src activities were observed during BMP2 stimulation. The removal of extracellular calcium, the application of membrane channel inhibitors streptomycin or nifedipine, the FAK inhibitor PF-573228 (PF228), and the alkaline phosphatase (ALP) siRNA all blocked the BMP2-stimulated [Ca(2+) ]i increase, while the Src inhibitor PP1 did not. In contrast, a gentle decrease of endoplasmic reticulum calcium concentration was found after BMP2 stimulation, which could be blocked by both streptomycin and PP1. Further experiments revealed that BMP2-induced FAK activation could not be inhibited by PP1, ALP siRNA or the calcium channel inhibitor nifedipine. PF228, but not PP1 or calcium channel inhibitors, suppressed ALP elevation resulting from BMP2 stimulation. Therefore, our results suggest that BMP2 can increase [Ca(2+) ]i through extracellular calcium influx regulated by FAK and ALP and can deplete ER calcium through Src signaling simultaneously. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1725-1733, 2016.

  4. Zinc modulation of calcium activity at the photoreceptor terminal: a calcium imaging study.

    Science.gov (United States)

    Anastassov, Ivan; Shen, Wen; Ripps, Harris; Chappell, Richard L

    2013-07-01

    There is abundant experimental evidence that zinc ions (Zn(2+)) are present in the synaptic vesicles of vertebrate photoreceptors, and that they are co-released with glutamate. Here we show that increasing the concentration of extracellular zinc (2 μM-2 mM) suppresses the entry of calcium into the synaptic terminals of isolated salamander double cones. The resultant dose-dependent curve was fit by an inverse Hill equation having an IC50 of 38 μM, and Hill coefficient of 1.1. Because there is currently no reliable way to measure the concentration of extracellular zinc, it is not known whether the zinc released under normal circumstances is of physiological significance. In an attempt to circumvent this problem we used zinc chelators to reduce the available pool of endogenous zinc. This enabled us to determine how the absence of zinc affected calcium entry. We found that when intra- or extra-cellular zinc was chelated by 250 μM of membrane-permeable TPEN or 500 μM of membrane-impermeable histidine, there was a significant rise in the depolarization-induced intracellular calcium level within photoreceptor terminals. This increase in internal [Ca(2+)] will undoubtedly lead to a concomitant increase in glutamate release. In addition, we found that blocking the L-type calcium channels that are expressed on the synaptic terminals of photoreceptors with 50 μM nicardipine or 100 μM verapamil abolished the effects of zinc chelation. These findings are a good indication that, when released in vivo, the zinc concentration is sufficient to suppress voltage-gated calcium channels, and reduce the rate of glutamate release from photoreceptor terminals.

  5. The crystal growth kinetics of alpha calcium sulfate hemihydrate in concentrated CaCl2-HCl solutions

    Science.gov (United States)

    Feldmann, Thomas; Demopoulos, George P.

    2012-07-01

    The crystal growth kinetics of calcium sulfate α-hemihydrate (α-HH) in nearly constant supersaturated HCl-CaCl2 solutions were investigated. Two types of solutions were used, the first had a low HCl (1.4 mol/L) and high CaCl2 (2.8 mol/L) concentration and the second had a high HCl (5.6 mol/L) and low CaCl2 (0.7 mol/L) concentration. These conditions were chosen to represent the first and last stage of a newly developed stage-wise HCl regeneration process. The seeded growth experiments were carried out in a stirred, temperature controlled semi-batch reactor in which supersaturation was kept constant by simultaneous addition of CaCl2 and Na2SO4 solutions. The influence of the following parameters on α-HH crystal growth was studied: temperature (70-95 °C), specific power input of stirring (0.02-1.29 W/kg) and equimolar inflow rate of CaCl2 and Na2SO4 (0-0.6 mol/h). The crystal growth rate was derived from particle size distribution measurements made with the laser light diffraction technique. It was found that the surface area normalized crystal growth rate increased linearly with the molar inflow rate up to 0.3 mol/h, at higher inflow rates no further increase of the growth rate was observed. Temperature and specific power input, within the investigated ranges, did not show a marked effect on the growth rate, attributable to a diffusion/adsorption controlled growth process. An interesting finding of the present research is the establishment of a positive relationship between the narrowing of the width of the particle size distribution with increasing crystal growth rate. The results show that the resulting particle size distribution is positively related to the reagent inflow rate, a finding that can be applied to the industrial design and scale-up of the α-HH crystallization/HCl regeneration process.

  6. 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

  7. Energy recovery from effluents of sugar processing industries in the UASB reactors seeded with granular sludge developed under low and high concentrations of calcium ion

    Energy Technology Data Exchange (ETDEWEB)

    Raphael, D.M.; Rubindamayugi, M.S.T. [Univ. of Dar es Salaam, Dept. of Botany, Applied Microbiology Unit (Tanzania, United Republic of)

    1997-12-31

    The digestion of wastewater from sugar processing industries in a single phase UASB reactor was evaluated by a step wise increase in organic loading rate. This study was conducted to compare the treatability of effluents from sugar processing industries in a single phase UASB reactors inoculated with granular sludge developed under low and high concentrations of calcium ions. At OLR of 11.34 g COD/l/day and HRT of 16 hours, UASB reactor R2 attained a COD removal efficiency of 90% with a maximum methane production rate of 3 l/l/day. From the results, the digestion of the wastewater from sugar industries in the UASB reactor inoculated with granular sludge developed under high calcium ion concentration seem feasible with regard to COD removal efficiency and methane production rate. (au) 24 refs.

  8. The role of calcium and nicotinic acid adenine dinucleotide phosphate (NAADP) in human osteoclast formation and resorption.

    Science.gov (United States)

    Cheng, X; Hookway, E S; Kashima, T; Oppermann, U; Galione, A; Athanasou, N A

    2015-01-01

    Osteoclasts are specialised bone resorbing cells which form by fusion of circulating mononuclear phagocyte precursors. Bone resorption results in the release of large amounts of calcium into the extracellular fluid (ECF), but it is not certain whether changes in extracellular calcium concentration [Ca(2+)]e influence osteoclast formation and resorption. In this study, we sought to determine the effect of [Ca(2+)]e and NAADP, a potent calcium mobilising messenger that induces calcium uptake, on human osteoclast formation and resorption. CD14+ human monocytes were cultured with M-CSF and RANKL in the presence of different concentrations of calcium and NAADP and the effect on osteoclast formation and resorption evaluated. We found that the number of TRAP+ multinucleated cells and the extent of lacunar resorption were reduced when there was an increase in extracellular calcium and NAADP. This was associated with a decrease in RANK mRNA expression by CD14+ cells. At high concentrations (20 mM) of [Ca(2+)]e mature osteoclast resorption activity remained unaltered relative to control cultures. Our findings indicate that osteoclast formation is inhibited by a rise in [Ca(2+)]e and that RANK expression by mononuclear phagocyte osteoclast precursors is also [Ca(2+)]e dependent. Changes in NAADP also influence osteoclast formation, suggesting a role for this molecule in calcium handling. Osteoclasts remained capable of lacunar resorption, even at high ECF [Ca(2+)]e, in keeping with their role in physiological and pathological bone resorption.

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

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Yunpeng Cao

    2008-01-01

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

  10. Changes in intracellular calcium concentration in crustacean (Callinectes sapidus) Y-organs: relation to the hemolymphatic ecdysteroid titer.

    Science.gov (United States)

    Chen, Hsiang-Yin; Watson, R Douglas

    2011-01-01

    Secretion of ecdysteroid molting hormones by crustacean Y-organs is negatively regulated (inhibited) by molt-inhibiting hormone (MIH), a neuropeptide produced by neurosecretory cells in eyestalk ganglia. The inhibitory effect of MIH is mediated by one or more cyclic nucleotide second messengers. In addition, available data indicate that ecdysteroidogenesis is positively regulated (stimulated) by intracellular calcium. However, despite the apparent critical role of calcium in regulating ecdysteroidogenesis, the level of Ca(2+) in Y-organs cells has not been previously determined. In studies reported here, eyestalks were ablated from blue crabs (Callinectes sapidus) to remove the endogenous source of MIH and activate Y-organs. At 0, 3, 6, and 9 days after eyestalk ablation (D0, D3, D6, and D9, respectively), the level of Ca(2+) in Y-organ cells was determined using a fluorescent calcium indicator (Fluo-4), and the hemolymphatic ecdysteroid titer was determined by radioimmunoassay. Calcium fluorescence in D6 Y-organs was 3.5-fold higher than that in D0 controls; calcium fluorescence in D9 Y-organs was 3.9-fold higher than in D0 controls (P<0.05). Measurement of fluorescence along a transect drawn through representative cells indicated that the calcium fluorescence was localized to cytoplasm and not to nuclei. Associated with the increase in intracellular Ca(2+) was a significant increase in the hemolymphatic ecdysteroid titer: The level of ecdysteroids in hemolymph rose from 5.5 ng/mL on D0 to 49.6 ng/mL on D6 and 87.2 ng/mL on D9 (P<0.05). The results are consistent with the hypothesis that ecdysteroidogenesis is stimulated by an increase in intracellular Ca(2+).

  11. Lead interferes with calcium entry through membrane pores

    Energy Technology Data Exchange (ETDEWEB)

    Buesselberg, D.; Schirrmacher, K.; Domann, R.; Wiemann, M. [Universitaet-GH Essen, Inst. fuer Physiologie, Essen (Germany)

    1998-06-01

    of this effect was not reversible. Other agonist activated channel currents (kainate and quisqualate) are not affected. In OBL cells, the calcium entry through calcium release activated channels (CRACs) was reduced in a concentration dependent manner by extracellular Pb{sup 2+}, the concentrations were between 2 and 20 {mu}M. Surprisingly the electric coupling through gap junction channels in OBL cells was not reduced by either extracellular or intracellular Pb{sup 2+} (5-25 {mu}M). (orig.) (orig.) With 4 figs., 26 refs.

  12. Changes of Calcium Concentration after Ceftriaxone Sodium Mixed with Different Concentrations of Calcium Solution%头孢曲松钠与不同浓度含钙溶液混合后钙离子浓度的变化研究

    Institute of Scientific and Technical Information of China (English)

    林金华; 周艳芳; 凌丽燕; 姜宠华; 陆卫良

    2013-01-01

    目的:研究头孢曲松钠与含钙溶液产生沉淀的浓度范围,指导临床合理用药.方法:采用全自动生化测定仪测定初始钙离子浓度为0.16、0.38、0.61、0.85、1.10、1.35、1.58、1.84、2.13、2.37 mmol/L的合钙溶液与1、0.5、0.25 g头孢曲松钠混合后0、0.5、1.0、2.0、3.0、4.0、6.0、24.0h内上清液中的钙离子浓度变化,并分析其变化规律.结果:1、0.5、0.25 g头孢曲松钠与各个初始浓度的含钙溶液混合后,上清液中钙离子浓度相互间区别不大;3种头孢曲松钠加入量的上清液中钙离子浓度0.5 h时均较0h时下降,但1.0~24.0h与0h比较均变化不大;3种头孢曲松钠加入量的上清液中钙离子浓度差别不大;且从0.5~24.0h初始钙离子浓度越高,上清液中的钙离子浓度反而更低;钙离子浓度≥1.35 mmol/L时均产生沉淀,浓度越大,产生的沉淀越多,钙离子浓度≤0.85mmol/L时并未见沉淀产生.结论:高血钙患者(血钙>2.6 mmol/L),特别是甲状旁腺危象患者(血钙>4 mmol/L),如需使用头孢曲松钠,使用前应该测定血清钙离子浓度,≥1.35 mmol/L时,风险较大,应避免使用;如果合用含钙制剂(包括口服),应增加水分的摄入,以稀释尿液中的钙离子浓度,从而降低使用风险.%OBJECTIVE: To study the range of concentration that the precipitation appears after ceftriaxone sodium mixed with solution containing calcium, and to provide reference for rational use of drugs in the clinic. METHODS:Using automatic biochemical analyzer, the changes of calcium concentrations in supernatant were determined within 0, 0.5, 1.0, 2.0, 3.0, 4.0, 6.0 and 24.0 h after solution containing calcium (initial concentrations of 0.16, 0.38, 0.61, 0.85, 1.10, 1.35, 1.58, 1.84, 2.13 and 2.37 mmol/L) mixed with ceftriaxone sodium (1, 0.5, 0.25 g); the variation regularity was analyzed. RESULTS: The concentration of calcium ions had no significant difference when ceftriaxone sodium

  13. Effect of extracellular adenosine 5'-triphosphate on cryopreserved epididymal cat sperm intracellular ATP concentration, sperm quality, and in vitro fertilizing ability.

    Science.gov (United States)

    Thuwanut, Paweena; Arya, Nlin; Comizzoli, Pierre; Chatdarong, Kaywalee

    2015-09-15

    Intracellular adenosine 5'-triphosphate (ATP) is essential for supporting sperm function in the fertilization process. During cryopreservation, damage of sperm mitochondrial membrane usually leads to compromised production of intracellular ATP. Recently, extracellular ATP (ATPe) was introduced as a potent activator of sperm motility and fertilizing ability. This study aimed to evaluate (1) levels of intracellular ATP in frozen-thawed epididymal cat sperm after incubation with ATPe and (2) effects of ATPe on epididymal cat sperm parameters after freezing and thawing. Eighteen male cats were included. For each replicate, epididymal sperm from two cats were pooled to one sample (N = 9). Each pooled sample was cryopreserved with the Tris-egg yolk extender into three straws. After thawing, the first and second straws were incubated with 0-, 1.0-, or 2.5-mM ATPe for 10 minutes and evaluated for sperm quality at 10 minutes, 1, 3, and 6 hours after thawing and fertilizing ability. The third straw was evaluated for intracellular ATP concentration in control and with 2.5-mM ATPe treatment. Higher concentration of intracellular sperm ATP was observed in the samples treated with 2.5-mM ATPe compared to the controls (0.339 ± 0.06 μg/2 × 10(6) sperm vs. 0.002 ± 0.003 μg/2 × 10(6) sperm, P ≤ 0.05). In addition, incubation with 2.5-mM ATPe for 10 minutes promoted sperm motility (56.7 ± 5.0 vs. 53.3 ± 4.4%, P ≤ 0.05) and progressive motility (3.1 ± 0.2 vs. 2.8 ± 0.4, P ≤ 0.05), mitochondrial membrane potential (36.4 ± 5.5 vs. 28.7 ± 4.8%, P ≤ 0.05), and blastocyst rate (36.1 ± 7.0 and 28.8 ± 7.4%, P ≤ 0.05) compared with the controls. In contrast, ATPe remarkably interfered acrosome integrity after 6 hours of postthawed incubation. In sum, the present finding that optimal incubation time of postthaw epididymal cat sperm under proper ATPe condition might constitute a rationale for the studies on other endangered wild felids regarding sperm quality and embryo

  14. Novel strategies in drug discovery of the calcium-sensing receptor based on biased signaling

    DEFF Research Database (Denmark)

    Thomsen, Alex Rojas Bie; Smajilovic, Sanela; Bräuner-Osborne, Hans

    2012-01-01

    A hallmark of chronic kidney disease is hyperphosphatemia due to renal phosphate retention. Prolonged parathyroid gland exposure to hyperphosphatemia leads to secondary hyperparathyroidism characterized by hyperplasia of the glands and excessive secretion of parathyroid hormone (PTH), which causes...... renal osteodystrophy. PTH secretion from the parathyroid glands is controlled by the calcium-sensing receptor (CaSR) that senses extracellular calcium. High extracellular calcium activates the CaSR causing inhibition of PTH secretion through multiple signaling pathways. Cinacalcet is the first drug...... targeting the CaSR and can be used to effectively control and reduce PTH secretion in PTH-related diseases. Cinacalcet is a positive allosteric modulator of the CaSR and affects PTH secretion from parathyroid glands by shifting the calcium-PTH concentration-response curve to the left. One major disadvantage...

  15. Effects of fructose-1,6-diphosphate on concentration of calcium and activities of sarcoplosnic Ca2+-ATPase in cardiomyocytes of Adriamycin-treated rats

    Institute of Scientific and Technical Information of China (English)

    CAI Wei; CHEN Jun-zhu; RUAN Li-ming; WANG Yi-na

    2005-01-01

    Objective: To observe the effects of fructose-1,6-diphosphate (FDP) on serum levels of cardiac troponin I (cTnI) and creatine kinase-MB (CK-MB), as well as the concentration of calcium in cardiomyocytes (Myo[Ca2+]) and activity of sarcoplosnic Ca2+-ATPase (SRCa2+-ATPase) in Adriamycin (ADR)-treated rats. Methods: Rats were intraperitoneally injected with ADR (2.5mg/kg every other day for 6 times) and then with different dosages of FDP (every other day for twenty-one times). Bi-antibodies sandwich Enzyme linked immune absorption assay (ELISA) was performed to detect serum level of cTnI. CK-MB was detected by monoclonal antibody, Myo[Ca2+] was detected by fluorescent spectrophotometry and the activity of SRCa2+-ATPase was detected by inorganic phosphate method. Results: FDP (300, 600, 1200 mg/kg) significantly reduced the serum levels of cTnI and CK-MB, while at the same time decreased calcium concentration and increased SRCa2+-ATPase activity in cardiomyocytes of ADR-treated rats (P<0.01). Conclusions: FDP might alleviate the cardiotoxic effects induced by ADR through decreasing calcium level as well as increasing SRCa2+-ATPase activity in cardiomyocytes.

  16. Study of the effect of magnesium concentration on the deposit of allotropic forms of calcium carbonate and related carbon steel interface behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ben Amor, Y., E-mail: yasser_ben@yahoo.f [Institut Superieur des Sciences et Technologies de l' Environnement de Borj-Cedria, B.P 1003, Hammam-Lif 2050 (Tunisia); Bousselmi, L. [Laboratoire Traitement et Recyclage des Eaux, B.P 273, Hammam-Lif, Technopole de Borj-Cedria, 8020 Soliman (Tunisia); Tribollet, B. [UPR 15 CNRS - Physique des liquides et Electrochimie, Universite Pierre et Marie Curie - Tour 22, 4 place Jussieu, 75252 Paris Cedex 05 (France); Triki, E. [Unite de recherche Corrosion et Protection des metalliques, Ecole Nationale d' Ingenieurs de Tunis, P.B. 37, 1002 Tunis, Belvedere (Tunisia)

    2010-06-30

    Different allotropic forms of calcium carbonate scales were electrochemically deposited on a carbon steel surface in artificial underground Tunisian water at -0.95 V{sub SCE} and various Mg{sup 2+} concentrations. Because of the importance of the diffusion process, the rotating disk electrode was used. The deposition kinetics were analyzed by chronoamperometry measurements and the calcareous layers were characterized by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The physical model proposed by Gabrielli was used to analyze the EIS measurements. Independent of the deposited allotropic form of calcium carbonate, the measurements showed that the oxygen reduction occurs in the pores formed between the CaCO{sub 3} crystals and the metallic surface.

  17. Ouabain enhancement of compound 48/80 induced histamine secretion from rat peritoneal mast cells: dependence on extracellular sodium

    DEFF Research Database (Denmark)

    Knudsen, T; Bertelsen, Niels Haldor; Johansen, Torben

    1992-01-01

    a measure of the Na(+)-K+ pump activity of the cells. Ouabain caused an immediate inhibition of the pump activity and a time-dependent increase in histamine secretion in the absence of extracellular calcium. No effect on the secretion was observed in the presence of calcium. The effect of ouabain......-free medium, the pump activity was inhibited and the enhancement by ouabain of the secretion of histamine was blocked. A less marked inhibition of the pump was found in a calcium-free medium containing magnesium. The inhibition exerted by magnesium was concentration-dependent (0-5 mM) as was the counteraction...... of sodium-calcium exchange caused by a decreased inward directed sodium gradient, the mechanism by which ouabain enhances the secretory response is likely to involve an increased binding of calcium to membrane binding sites....

  18. Calcium-sensing receptor and aquaporin 2 interplay in hypercalciuria-associated renal concentrating defect in humans. An in vivo and in vitro study.

    Science.gov (United States)

    Procino, Giuseppe; Mastrofrancesco, Lisa; Tamma, Grazia; Lasorsa, Domenica Rita; Ranieri, Marianna; Stringini, Gilda; Emma, Francesco; Svelto, Maria; Valenti, Giovanna

    2012-01-01

    One mechanism proposed for reducing the risk of calcium renal stones is activation of the calcium-sensing receptor (CaR) on the apical membranes of collecting duct principal cells by high luminal calcium. This would reduce the abundance of aquaporin-2 (AQP2) and in turn the rate of water reabsorption. While evidence in cells and in hypercalciuric animal models supports this hypothesis, the relevance of the interplay between the CaR and AQP2 in humans is not clear. This paper reports for the first time a detailed correlation between urinary AQP2 excretion under acute vasopressin action (DDAVP treatment) in hypercalciuric subjects and in parallel analyzes AQP2-CaR crosstalk in a mouse collecting duct cell line (MCD4) expressing endogenous and functional CaR. In normocalciurics, DDAVP administration resulted in a significant increase in AQP2 excretion paralleled by an increase in urinary osmolality indicating a physiological response to DDAVP. In contrast, in hypercalciurics, baseline AQP2 excretion was high and did not significantly increase after DDAVP. Moreover DDAVP treatment was accompanied by a less pronounced increase in urinary osmolality. These data indicate reduced urinary concentrating ability in response to vasopressin in hypercalciurics. Consistent with these results, biotinylation experiments in MCD4 cells revealed that membrane AQP2 expression in unstimulated cells exposed to CaR agonists was higher than in control cells and did not increase significantly in response to short term exposure to forskolin (FK). Interestingly, we found that CaR activation by specific agonists reduced the increase in cAMP and prevented any reduction in Rho activity in response to FK, two crucial pathways for AQP2 translocation. These data support the hypothesis that CaR-AQP2 interplay represents an internal renal defense to mitigate the effects of hypercalciuria on the risk of calcium precipitation during antidiuresis. This mechanism and possibly reduced medulla tonicity may

  19. Calcium-sensing receptor and aquaporin 2 interplay in hypercalciuria-associated renal concentrating defect in humans. An in vivo and in vitro study.

    Directory of Open Access Journals (Sweden)

    Giuseppe Procino

    Full Text Available One mechanism proposed for reducing the risk of calcium renal stones is activation of the calcium-sensing receptor (CaR on the apical membranes of collecting duct principal cells by high luminal calcium. This would reduce the abundance of aquaporin-2 (AQP2 and in turn the rate of water reabsorption. While evidence in cells and in hypercalciuric animal models supports this hypothesis, the relevance of the interplay between the CaR and AQP2 in humans is not clear. This paper reports for the first time a detailed correlation between urinary AQP2 excretion under acute vasopressin action (DDAVP treatment in hypercalciuric subjects and in parallel analyzes AQP2-CaR crosstalk in a mouse collecting duct cell line (MCD4 expressing endogenous and functional CaR. In normocalciurics, DDAVP administration resulted in a significant increase in AQP2 excretion paralleled by an increase in urinary osmolality indicating a physiological response to DDAVP. In contrast, in hypercalciurics, baseline AQP2 excretion was high and did not significantly increase after DDAVP. Moreover DDAVP treatment was accompanied by a less pronounced increase in urinary osmolality. These data indicate reduced urinary concentrating ability in response to vasopressin in hypercalciurics. Consistent with these results, biotinylation experiments in MCD4 cells revealed that membrane AQP2 expression in unstimulated cells exposed to CaR agonists was higher than in control cells and did not increase significantly in response to short term exposure to forskolin (FK. Interestingly, we found that CaR activation by specific agonists reduced the increase in cAMP and prevented any reduction in Rho activity in response to FK, two crucial pathways for AQP2 translocation. These data support the hypothesis that CaR-AQP2 interplay represents an internal renal defense to mitigate the effects of hypercalciuria on the risk of calcium precipitation during antidiuresis. This mechanism and possibly reduced

  20. Effects of high doses of magnesium in drinking water and voluntary wheel running on magnesium and calcium concentrations in rats.

    Science.gov (United States)

    Meludu, S C; Nishimuta, M; Aboh, N A; Okonkwo, C; Dioka, C E

    2002-12-01

    The effect of high magnesium intake in addition to supplementation and voluntary wheel activity on magnesium and calcium homeostasis was investigated in rats. Thirty-six 5-week-old male Wistar rats were divided into four groups (n = 9). Groups 2 and 4 received five hundred ppm of elemental magnesium as MgCl2 provided in drinking water. After 1 week of acclimatization and 4 weeks of supplement and/or exercise, the animals were fasted and sacrificed. It appears that magnesium supplementation as well as exercise played some significant role in the homeostatic changes of magnesium and calcium. This could be of great significance in better understanding of mineral homeostasis particularly in sports medicine.

  1. Vitamin D Metabolites and Their Association with Calcium, Phosphorus, and PTH Concentrations, Severity of Illness, and Mortality in Hospitalized Equine Neonates.

    Directory of Open Access Journals (Sweden)

    Ahmed M Kamr

    Full Text Available Hypocalcemia is a frequent abnormality that has been associated with disease severity and outcome in hospitalized foals. However, the pathogenesis of equine neonatal hypocalcemia is poorly understood. Hypovitaminosis D in critically ill people has been linked to hypocalcemia and mortality; however, information on vitamin D metabolites and their association with clinical findings and outcome in critically ill foals is lacking. The goal of this study was to determine the prevalence of vitamin D deficiency (hypovitaminosis D and its association with serum calcium, phosphorus, and parathyroid hormone (PTH concentrations, disease severity, and mortality in hospitalized newborn foals.One hundred newborn foals ≤72 hours old divided into hospitalized (n = 83; 59 septic, 24 sick non-septic [SNS] and healthy (n = 17 groups were included. Blood samples were collected on admission to measure serum 25-hydroxyvitamin D3 [25(OHD3], 1,25-dihydroxyvitamin D3 [1,25(OH 2D3], and PTH concentrations. Data were analyzed by nonparametric methods and univariate logistic regression. The prevalence of hypovitaminosis D [defined as 25(OHD3 <9.51 ng/mL] was 63% for hospitalized, 64% for septic, and 63% for SNS foals. Serum 25(OHD3 and 1,25(OH 2D3 concentrations were significantly lower in septic and SNS compared to healthy foals (P<0.0001; P = 0.037. Septic foals had significantly lower calcium and higher phosphorus and PTH concentrations than healthy and SNS foals (P<0.05. In hospitalized and septic foals, low 1,25(OH2D3 concentrations were associated with increased PTH but not with calcium or phosphorus concentrations. Septic foals with 25(OHD3 <9.51 ng/mL and 1,25(OH 2D3 <7.09 pmol/L were more likely to die (OR=3.62; 95% CI = 1.1-12.40; OR = 5.41; 95% CI = 1.19-24.52, respectively.Low 25(OHD3 and 1,25(OH2D3 concentrations are associated with disease severity and mortality in hospitalized foals. Vitamin D deficiency may contribute to a pro-inflammatory state in equine

  2. Concentration trends for lead and calcium-normalized lead in fish fillets from the Big River, a mining-contaminated stream in southeastern Missouri USA

    Science.gov (United States)

    Schmitt, Christopher J.; McKee, Michael J.

    2016-01-01

    Lead (Pb) and calcium (Ca) concentrations were measured in fillet samples of longear sunfish (Lepomis megalotis) and redhorse suckers (Moxostoma spp.) collected in 2005–2012 from the Big River, which drains a historical mining area in southeastern Missouri and where a consumption advisory is in effect due to elevated Pb concentrations in fish. Lead tends to accumulated in Ca-rich tissues such as bone and scale. Concentrations of Pb in fish muscle are typically low, but can become elevated in fillets from Pb-contaminated sites depending in part on how much bone, scale, and skin is included in the sample. We used analysis-of-covariance to normalize Pb concentration to the geometric mean Ca concentration (415 ug/g wet weight, ww), which reduced variation between taxa, sites, and years, as was the number of samples that exceeded Missouri consumption advisory threshold (300 ng/g ww). Concentrations of Pb in 2005–2012 were lower than in the past, especially after Ca-normalization, but the consumption advisory is still warranted because concentrations were >300 ng/g ww in samples of both taxa from contaminated sites. For monitoring purposes, a simple linear regression model is proposed for estimating Ca-normalized Pb concentrations in fillets from Pb:Ca molar ratios as a way of reducing the effects of differing preparation methods on fillet Pb variation.

  3. EFFECT OF THE TOTAL SAPONIN OF DIPSACUS ASPER ON INTRACELLULAR FREE CALCIUM CONCENTRATION IN THE CELLULAR MODEL OF ALZHEIMER'S DISEASE-SCANNING CONFOCAL MICROSCOPY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To study the effect of ginsenoside Rb1(Rb1) and total saponin of dipsacus asper(tSDA) on intracellular free calcium concentration([Ca2+]i) mediated by β-amyloid protein(A β).So as to lay a foundation for developing effective Chinese traditional medicine to treat Alzheimer's disease(AD).Methods The technique of laser scanning confocal microscopy combining primary cultured neurons was adopted to quantitatively analyze the change of [Ca2+]i.Results The [Ca2+]i of primary cultured hippocampal neurons was (185.76±56.22)nmol*L-1 on basal levels.Control group showed obvious change of calcium vibration,[Ca2+]i was elevated to (1383.78±62.83)nmol*L-1.The peak of [Ca2+]i of Rb1 group reached (311.95±32.67)nmol*L-1 and was lower than that of control group (P<0.01).The tSDA group displayed distinct change of calcium vibration too,and [Ca2+]i reached (358.01±35.42)nmol*L-1.There was a significant difference in [Ca2+]i between control and tSDA group (P<0.01).Conclusion The research indicated that one of mechanisms by which Rb1 and tSDA protected the neurons was to maintain the balance of [Ca2+]i.

  4. Predicting Gran alkalinity and calcium concentrations in river waters over a national scale using a novel modification to the G-BASH model.

    Science.gov (United States)

    Cresser, Malcolm S; Ahmed, Nayan; Smart, Richard P; Arowolo, Toyin; Calver, Louise J; Chapman, Pippa J

    2006-09-01

    Monthly stream water calcium and Gran alkalinity concentration data from 11 sub-catchments of the Nether Beck in the English Lake District have been used to appraise the transferability of the Scottish, River Dee-based G-BASH model. Readily available riparian zone geochemistry and flow paths were used initially to predict minimum and mean stream water concentrations at the Nether Beck, based on calibration equations from the River Dee catchment data. Predicted values significantly exceeded observed values. Differences in runoff between the two areas, leading to a dilution effect in the Nether Beck, explained most of the difference between observed and predicted values. Greater acid deposition in the Lake District also reduced stream water Gran alkalinity concentrations in that area. If regional differences in precipitation, evapotranspiration and pollutant deposition are incorporated into the model, it may then be used reliably to predict catchment susceptibility to acidification over a wide regional (national) scale.

  5. Nifedipine treatment reduces resting calcium concentration, oxidative and apoptotic gene expression, and improves muscle function in dystrophic mdx mice.

    Science.gov (United States)

    Altamirano, Francisco; Valladares, Denisse; Henríquez-Olguín, Carlos; Casas, Mariana; López, Jose R; Allen, Paul D; Jaimovich, Enrique

    2013-01-01

    Duchenne Muscular Dystrophy (DMD) is a recessive X-linked genetic disease, caused by mutations in the gene encoding dystrophin. DMD is characterized in humans and in mdx mice by a severe and progressive destruction of muscle fibers, inflammation, oxidative/nitrosative stress, and cell death. In mdx muscle fibers, we have shown that basal ATP release is increased and that extracellular ATP stimulation is pro-apoptotic. In normal fibers, depolarization-induced ATP release is blocked by nifedipine, leading us to study the potential therapeutic effect of nifedipine in mdx muscles and its relation with extracellular ATP signaling. Acute exposure to nifedipine (10 µM) decreased [Ca(2+)]r, NF-κB activity and iNOS expression in mdx myotubes. In addition, 6-week-old mdx mice were treated with daily intraperitoneal injections of nifedipine, 1 mg/Kg for 1 week. This treatment lowered the [Ca(2+)]r measured in vivo in the mdx vastus lateralis. We demonstrated that extracellular ATP levels were higher in adult mdx flexor digitorum brevis (FDB) fibers and can be significantly reduced after 1 week of treatment with nifedipine. Interestingly, acute treatment of mdx FDB fibers with apyrase, an enzyme that completely degrades extracellular ATP to AMP, reduced [Ca(2+)]r to a similar extent as was seen in FDB fibers after 1-week of nifedipine treatment. Moreover, we demonstrated that nifedipine treatment reduced mRNA levels of pro-oxidative/nitrosative (iNOS and gp91(phox)/p47(phox) NOX2 subunits) and pro-apoptotic (Bax) genes in mdx diaphragm muscles and lowered serum creatine kinase (CK) levels. In addition, nifedipine treatment increased muscle strength assessed by the inverted grip-hanging test and exercise tolerance measured with forced swimming test in mdx mice. We hypothesize that nifedipine reduces basal ATP release, thereby decreasing purinergic receptor activation, which in turn reduces [Ca(2+)]r in mdx skeletal muscle cells. The results in this work open new perspectives

  6. Nifedipine treatment reduces resting calcium concentration, oxidative and apoptotic gene expression, and improves muscle function in dystrophic mdx mice.

    Directory of Open Access Journals (Sweden)

    Francisco Altamirano

    Full Text Available Duchenne Muscular Dystrophy (DMD is a recessive X-linked genetic disease, caused by mutations in the gene encoding dystrophin. DMD is characterized in humans and in mdx mice by a severe and progressive destruction of muscle fibers, inflammation, oxidative/nitrosative stress, and cell death. In mdx muscle fibers, we have shown that basal ATP release is increased and that extracellular ATP stimulation is pro-apoptotic. In normal fibers, depolarization-induced ATP release is blocked by nifedipine, leading us to study the potential therapeutic effect of nifedipine in mdx muscles and its relation with extracellular ATP signaling. Acute exposure to nifedipine (10 µM decreased [Ca(2+]r, NF-κB activity and iNOS expression in mdx myotubes. In addition, 6-week-old mdx mice were treated with daily intraperitoneal injections of nifedipine, 1 mg/Kg for 1 week. This treatment lowered the [Ca(2+]r measured in vivo in the mdx vastus lateralis. We demonstrated that extracellular ATP levels were higher in adult mdx flexor digitorum brevis (FDB fibers and can be significantly reduced after 1 week of treatment with nifedipine. Interestingly, acute treatment of mdx FDB fibers with apyrase, an enzyme that completely degrades extracellular ATP to AMP, reduced [Ca(2+]r to a similar extent as was seen in FDB fibers after 1-week of nifedipine treatment. Moreover, we demonstrated that nifedipine treatment reduced mRNA levels of pro-oxidative/nitrosative (iNOS and gp91(phox/p47(phox NOX2 subunits and pro-apoptotic (Bax genes in mdx diaphragm muscles and lowered serum creatine kinase (CK levels. In addition, nifedipine treatment increased muscle strength assessed by the inverted grip-hanging test and exercise tolerance measured with forced swimming test in mdx mice. We hypothesize that nifedipine reduces basal ATP release, thereby decreasing purinergic receptor activation, which in turn reduces [Ca(2+]r in mdx skeletal muscle cells. The results in this work open new

  7. Predicting Gran alkalinity and calcium concentrations in river waters over a national scale using a novel modification to the G-BASH model

    Energy Technology Data Exchange (ETDEWEB)

    Cresser, Malcolm S. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)]. E-mail: msc5@york.ac.uk; Ahmed, Nayan [Division of Soil Science and Agricultural Chemistry, IARI, New Delhi 110012 (India); Smart, Richard P. [Central Science Laboratory, Sand Hutton, York YO41 1LZ (United Kingdom); Arowolo, Toyin [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom); Calver, Louise J. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom); Chapman, Pippa J. [School of Geography, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom)

    2006-09-15

    Monthly stream water calcium and Gran alkalinity concentration data from 11 sub-catchments of the Nether Beck in the English Lake District have been used to appraise the transferability of the Scottish, River Dee-based G-BASH model. Readily available riparian zone geochemistry and flow paths were used initially to predict minimum and mean stream water concentrations at the Nether Beck, based on calibration equations from the River Dee catchment data. Predicted values significantly exceeded observed values. Differences in runoff between the two areas, leading to a dilution effect in the Nether Beck, explained most of the difference between observed and predicted values. Greater acid deposition in the Lake District also reduced stream water Gran alkalinity concentrations in that area. If regional differences in precipitation, evapotranspiration and pollutant deposition are incorporated into the model, it may then be used reliably to predict catchment susceptibility to acidification over a wide regional (national) scale. - A modified G-BASH model predicts calcium and Gran alkalinity in streams at a national scale, taking account of regional deposition and climatic variations.

  8. Effect of reduced dietary calcium concentration and phytase supplementation on calcium and phosphorus utilization in weanling pigs with modified mineral status.

    Science.gov (United States)

    Létourneau-Montminy, M P; Narcy, A; Magnin, M; Sauvant, D; Bernier, J F; Pomar, C; Jondreville, C

    2010-05-01

    The present study was conducted to assess the effect of 2 dietary Ca concentrations on P and Ca digestive and metabolic utilization in weanling pigs fed diets providing practical concentrations of P, with or without phytase. The responses of pigs fed diets adequate or moderately deficient in Ca and P postweaning were compared. A total of 60 pigs weaned at 28 d of age were used. Two groups of 30 pigs with differing mineral status resulted from a 10-d depletion period, during which the animals received depletion diets (DD) that consisted of corn-soybean meal with either 1.42% Ca and 0.80% P (DD+) or 0.67% Ca and 0.43% P (DD-), designed to achieve the same Ca:digestible P ratio. At the end of the depletion period, a plasma sample was taken from each pig and 12 pigs (6 from each group) were slaughtered for bone assessment to establish the baseline mineral status. The animals fed the DD- diet had signs of P deficiency with reduced plasma P (13%; P pigs from each group were fed 1 of 4 repletion diets: 1) 0.56% P, 1.06% Ca; 2) 0.56% P, 0.67% Ca; 3) diet 1 + 1,000 phytase units (FTU) of Natuphos phytase/kg; and 4) diet 2 + 1,000 FTU of Natuphos phytase/kg. Total feces and urine were collected from d 5 to 11, and a blood sample was taken from each pig at d 11 and 25. The initial moderate P deficiency (DD-) stimulated Ca absorption (5%; P pigs achieved full recovery of femur DM and ash weight when they received phytase, whereas ash concentration tended to remain reduced by 3% (P = 0.08). Phosphorus digestibility was improved in the diets supplemented with phytase (73.0 vs. 56.0%; P dietary Ca decreased P digestibility (65.6 vs. 63.4%; P dietary Ca reduced equally P digestibility with and without phytase and did not influence the efficiency of phytase in releasing P in the digestive tract. In pigs fed diets with phytase, however, the reduction of Ca (Ca:P from 1.9 to 1.3) increased urinary P losses 5-fold. Those extra losses were due to a lack of Ca for skeleton ash

  9. Influence of salinity and supplementary calcium on vegetative growth, fruit yield and concentration of some nutrients in hydroponically-grown strawberry

    Directory of Open Access Journals (Sweden)

    N. Karimian1

    2011-07-01

    Full Text Available Optimum level of calcium (Ca in saline soils is a critical factor in controlling the toxic effect of some ions, especially in plants sensitive to sodium (Na and chlorine (Cl damage. To evaluate the effect of salinity and supplementary calcium (S-Ca on vegetative growth, fruit yield and concentration of some nutrients in roots, shoots, and fruits of strawberry (Fragaria ananaassa Duch cv. Selva, a greenhouse experiment was carried out in 5×3 factorial experiment arranged in a completely randomized design with three replications. Treatments included three levels of salinity (0, 20, and 40 mM as NaCl and five levels of supplementary Ca (0, 5, and 10 mM added to nutrient solution, 0.5 and 1% foliar application as CaCl2. The results showed that addition of NaCl to nutrient solution, negatively affected root and shoot dry weight and fruit fresh weight. Reduction of shoot dry weight and fruit fresh weight were higher than those of roots. Application of S-Ca not only did not improve the vegetative growth and fruit yield, but rather decreased them. Salinity (NaCl treatments increased the concentration of Na in roots, shoots and fruits but application of 5 and 10 mM S-Ca levels decreased Na concentration in roots. By addition of NaCl to nutrient solution, the shoot Ca concentration was decreased in some treatments, but roots and fruits’ Ca concentration was not affected. Application of S-Ca increased Ca concentration in all organs of strawberry plants. By application of NaCl, potassium (K concentration was decreased in roots, but increased in fruits and was not affected in shoots. K concentration did not change in roots in the S-Ca applied treatments, but decreased in shoots and increased in fruits. Simultaneous application of salinity and S-Ca decreased roots’ magnesium concentration in all treatments and shoots and fruits’ concentration in some treatments. In general, although supplementary Ca increased its concentration in different plant organs

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

    Directory of Open Access Journals (Sweden)

    Haiyan eLi

    2011-11-01

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

  11. Effect of flunarizine and calcium on serotonin uptake in human and rat blood platelets and rat synaptosomes

    DEFF Research Database (Denmark)

    Jensen, P N; Smith, D F; Poulsen, J H

    1994-01-01

    in blood platelets, whereas no effect was observed in synaptosomes. Flunarizine inhibited serotonin uptake in a concentration dependent manner with an IC50 value of 1 mumol/L in blood platelets and 5 mumol/L in synaptosomes. The inhibition did not depend on the presence of extracellular calcium indicating...

  12. Extracellular Matrix Proteins

    Directory of Open Access Journals (Sweden)

    Linda Christian Carrijo-Carvalho

    2012-01-01

    Full Text Available Lipocalin family members have been implicated in development, regeneration, and pathological processes, but their roles are unclear. Interestingly, these proteins are found abundant in the venom of the Lonomia obliqua caterpillar. Lipocalins are β-barrel proteins, which have three conserved motifs in their amino acid sequence. One of these motifs was shown to be a sequence signature involved in cell modulation. The aim of this study is to investigate the effects of a synthetic peptide comprising the lipocalin sequence motif in fibroblasts. This peptide suppressed caspase 3 activity and upregulated Bcl-2 and Ki-67, but did not interfere with GPCR calcium mobilization. Fibroblast responses also involved increased expression of proinflammatory mediators. Increase of extracellular matrix proteins, such as collagen, fibronectin, and tenascin, was observed. Increase in collagen content was also observed in vivo. Results indicate that modulation effects displayed by lipocalins through this sequence motif involve cell survival, extracellular matrix remodeling, and cytokine signaling. Such effects can be related to the lipocalin roles in disease, development, and tissue repair.

  13. The role of calcium in endotoxin-induced release of calcitonin gene-related peptide (CGRP) from rat spinal cord

    Institute of Scientific and Technical Information of China (English)

    唐跃明; 韩启德; 王宪

    1997-01-01

    In the present study, the role of calcium in endotoxin-induced CGRP release was studied. 2 .5-50 μg/mL endotoxin and 1 -10 mmol/L caffeine caused concentration-dependent increase of CGRP release from rat spinal cord in vitro. However, no additive effect could he found when caffeine and endotoxin were concomitantly incubated. By using capsaicin, Ca2+-free medium, Omega-Conotoxin, nifedipine, W-7, ryanodine, MgCl2, Tris-ATP, rutheni-um red, the results indicate that the release of CGRP evoked by endotoxin from the sensory fibers of rat spinal cord is dependent on extracellular calcium. After entering into the cell through the N-type calcium channel, calcium binds to calmodulin, and triggers calcium release from intracellular calcium store by activating the caffeine-sensitive but ryan-odine-insensitive mechanism.

  14. Salivary flow rate, pH, and concentrations of calcium, phosphate, and sIgA in Brazilian pregnant and non-pregnant women

    Directory of Open Access Journals (Sweden)

    Lindemann Laura

    2006-11-01

    Full Text Available Abstract Background Studies on salivary variables and pregnancy in Latin America are scarce. This study aimed to compare salivary flow rate, pH, and concentrations of calcium, phosphate, and sIgA of unstimulated whole saliva in pregnant and non-pregnant Brazilians. Methods Cross-sectional study. Sample was composed by 22 pregnant and 22 non-pregnant women attending the Obstetrics and Gynecology Clinics, São Lucas Hospital, in Porto Alegre city, South region of Brazil. Unstimulated whole saliva was collected to determine salivary flow rate, pH, and biochemical composition. Data were analyzed by Student t test and ANCOVA (two-tailed α = 0.05. Results No difference was found for salivary flow rates and concentrations of total calcium and phosphate between pregnant and non-pregnant women (p > 0.05. Pregnant women had lower pH (6.7 than non-pregnant women (7.5 (p Conclusion Some of the tested variables of unstimulated whole saliva were different between pregnant and non-pregnant Brazilians in this sample. Overall, the values of the tested salivary parameters were within the range of international references of normality.

  15. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    Science.gov (United States)

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K; Varani, James

    2012-12-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

  16. Role of extracellular cations in cell motility, polarity, and chemotaxis

    Directory of Open Access Journals (Sweden)

    Soll D

    2011-04-01

    Full Text Available David R Soll1, Deborah Wessels1, Daniel F Lusche1, Spencer Kuhl1, Amanda Scherer1, Shawna Grimm1,21Monoclonal Antibody Research Institute, Developmental Studies, Hybridoma Bank, Department of Biology, University of Iowa, Iowa City; 2Mercy Medical Center, Surgical Residency Program, Des Moines, Iowa, USAAbstract: The concentration of cations in the aqueous environment of free living organisms and cells within the human body influence motility, shape, and chemotaxis. The role of extracellular cations is usually perceived to be the source for intracellular cations in the process of homeostasis. The role of surface molecules that interact with extracellular cations is believed to be that of channels, transporters, and exchangers. However, the role of Ca2+ as a signal and chemoattractant and the discovery of the Ca2+ receptor have demonstrated that extracellular cations can function as signals at the cell surface, and the plasma membrane molecules they interact with can function as bona fide receptors that activate coupled signal transduction pathways, associated molecules in the plasma membrane, or the cytoskeleton. With this perspective in mind, we have reviewed the cationic composition of aqueous environments of free living cells and cells that move in multicellular organisms, most notably humans, the range of molecules interacting with cations at the cell surface, the concept of a cell surface cation receptor, and the roles extracellular cations and plasma membrane proteins that interact with them play in the regulation of motility, shape, and chemotaxis. Hopefully, the perspective of this review will increase awareness of the roles extracellular cations play and the possibility that many of the plasma membrane proteins that interact with them could also play roles as receptors.Keywords: extracellular cations, chemotaxis, transporters, calcium, receptors

  17. Increase of calcium and reduction of lactose concentration in milk by treatment with kefir grains and eggshell.

    Science.gov (United States)

    Fina, Brenda L; Brun, Lucas R; Rigalli, Alfredo

    2016-01-01

    Dairy products are the main source of calcium (Ca), but the loss of the consumption habit contributes to low consumption in adulthood, which leads to osteoporosis and increased fracture risk. Domestic use of kefir is straightforward and the eggshell is a natural discarded source of Ca. This paper proposes the development of an enriched Ca reduced lactose milk using eggshell and kefir. During the in vitro preparation, the pH, Ca and lactose contents were measured. Ca intestinal absorption of untreated milk and milk with kefir was compared. Finally, human volunteers consumed this dairy product and 24-h urine Ca was measured. Results showed that the beverage has lower lactose and higher Ca than untreated milk and milk with kefir. Intestinal Ca absorption was not different between both milks and an increase in urinary Ca excretion was observed in humans. This study provides a methodology to prepare at home a dairy product that could contribute to improve the Ca intake in adults.

  18. Concentration changeability of phosphorus, calcium and magnesium in selected partial drainage basins of the River Drwęca

    Directory of Open Access Journals (Sweden)

    Pius Bożena

    2015-12-01

    Full Text Available The paper presents the results of the research conducted between November 2008 and October 2009. The research included seasonal dynamics of the flow and runoff of phosphorus compounds (TP and P-PO43-, as well as Ca2+ and Mg2+ from 13 partial drainage basins of the River Drwęca. Water levels were registered automatically every day by recorders, and measurements of the flow were conducted once a month. Major differences were found in the water abundance as indicated by specific discharges in individual, partial drainage basins: from 1.87 dm3 s-1 km-2 (Lubianka - a lower part of the River Drwęca drainage basin to 8.22 dm3 s-1 km-2 (Gizela - an upper part of the River Drwęca drainage basin. The studied rivers were characterised by very diverse average content of total phosphorus compounds: from 0.047 mg dm-3 (Iłga to 0.816 mg dm-3 (Sandela; calcium: from 47.18 mg dm-3 (Iłga to 131.65 mg dm-3 (Trynka; and magnesium: from 9.71 mg dm-3 (Wel to 36.76 mg dm-3 (Struga Rychnowska. Analysis of variance carried out on hydrochemical properties of the studied rivers divides the rivers into two separate groups: rivers with much higher content of phosphorus, calcium and magnesium compounds (Struga Rychnowska, Trynka, Ruziec, Lubianka, Kujawka, Sandela and Gizela, and a group of rivers with low content of these compounds (Brynica, Brodniczanka, Skarlanka, Wel, Iłga.

  19. Calcium signaling in neurodegeneration

    Directory of Open Access Journals (Sweden)

    Dreses-Werringloer Ute

    2009-05-01

    Full Text Available Abstract Calcium is a key signaling ion involved in many different intracellular and extracellular processes ranging from synaptic activity to cell-cell communication and adhesion. The exact definition at the molecular level of the versatility of this ion has made overwhelming progress in the past several years and has been extensively reviewed. In the brain, calcium is fundamental in the control of synaptic activity and memory formation, a process that leads to the activation of specific calcium-dependent signal transduction pathways and implicates key protein effectors, such as CaMKs, MAPK/ERKs, and CREB. Properly controlled homeostasis of calcium signaling not only supports normal brain physiology but also maintains neuronal integrity and long-term cell survival. Emerging knowledge indicates that calcium homeostasis is not only critical for cell physiology and health, but also, when deregulated, can lead to neurodegeneration via complex and diverse mechanisms involved in selective neuronal impairments and death. The identification of several modulators of calcium homeostasis, such as presenilins and CALHM1, as potential factors involved in the pathogenesis of Alzheimer's disease, provides strong support for a role of calcium in neurodegeneration. These observations represent an important step towards understanding the molecular mechanisms of calcium signaling disturbances observed in different brain diseases such as Alzheimer's, Parkinson's, and Huntington's diseases.

  20. Dynamic observing the effect of different calcium concentration peritoneal dialysate on calcium-phosphorus metabolism in uremia patients under peritoneal dialysis%动态监测不同钙浓度腹膜透析液对尿毒症患者钙磷代谢的影响

    Institute of Scientific and Technical Information of China (English)

    田军; 刘楠梅; 张金元; 张雨帆; 高晶

    2008-01-01

    目的 动态监测使用不同钙浓度腹膜透析液行持续性不卧床腹膜透析(CAPD)对尿毒症患者钙磷代谢的影响.方法 将40例初行CAPD的尿毒症患者随机分为标准钙组和低钙组,每组各20例,行正规CAPD治疗并配合碳酸钙口服,观察12个月.结果 两组患者初行CAPD时,血清钙、磷、钙磷乘积及免疫反应性甲状旁腺索(iPTH)浓度比较差异均无统计学意义,普遍存在高磷血症及低iPTH血症.经过6个月的治疗,标准钙组患者的高钙、高磷血症进一步加重,而低钙组患者的血清钙[(2.29±0.27)mmol/L]、血清磷[(1.50±0.25)mmol/L]及钙磷乘积[(41.62±19.55)mg2/dl2]较治疗前显著降低,且均低于治疗后的同期标准钙组患者(P<0.01),iPTH则显著上升(P<0.01).在随后的6个月中,低钙组患者血清钙、钙磷乘积保持稳定并维持在正常范围,血清磷进一步降至正常范围(0.8~1.5 mmol/L),iPTH则维持在150 ng/L左右,与标准钙组比较有显著改善(P<0.01).结论 低钙浓度腹膜透析液有助于减轻尿毒症CAPD患者的钙磷代谢紊乱,延缓并发症的发生.%Objective To observe the effect of different calcium concentration peritoneal dialysate on calcium-phosphorus metabohsm in uremia patients under peritoneal dialysis. Methods Forty uremia patients who the first entered peritoneal dialysis were divided into two groups: standard calcium concentration group (20 cases), low calcium concentration group (20 cases). Treated with continuous ambulatory peritoneal dialysis (CAPD), combining with oral calcium carbonate, observing 12 months. Results When the first entering CAPD, serum calcium, phosphorus, calcium-phosphorus product, immunoreactive parathyroid hormone (iPTH) of the two groups had no differences. Hyperphosphatemia, lower iPTH were universal. After 6 months' treatment, hypercalcemia and hyperphosphatemia in standard calcium concentration group got increasingly serious.While in low calcium concentration group

  1. A model of calcium signaling and degranulation dynamics induced by laser irradiation in mast cells

    Institute of Scientific and Technical Information of China (English)

    SHI XiaoMin; ZHENG YuFan; LIU ZengRong; YANG WenZhong

    2008-01-01

    Recent experiments show that calcium signaling and degranulation dynamics induced by low power laser irradiation in mast cells must rely on extracellular Ca2+ influx. An analytical expression of Ca2+ flux through TRPV4 cation channel in response to interaction of laser photon energy and extracellular Ca2+ is deduced, and a model characterizing dynamics of calcium signaling and degranulation activated by laser irradiation in mast cells is established. The model indicates that the characteristics of calcium signaling and degranulation dynamics are determined by interaction between laser photon energy and Ca2+ influx. Extracellular Ca2+ concentration is so high that even small photon energy can activate mast cells, thus avoiding the possible injury caused by laser irradiation with shorter wavelengths. The model predicts that there exists a narrow parameter domain of photon energy and extracellular Ca2+ concentration of which results in cytosolic Ca2+ limit cycle oscillations, and shows that PKC activity is in direct proportion to the frequency of Ca2+ oscillations. With the model it is found that sustained and stable maximum plateau of cytosolic Ca2+ concentration can get optimal degranulation rate. Furthermore, the idea of introducing the realistic physical energy into model is applicable to modeling other physical signal transduction systems.

  2. Ca2+ signals induced from calcium stores in pancreatic islet β cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In single rat pancreatic β cells,using fura-2 microfluorometry to measure [Ca2+]i response upon different stimuli,the ways of calcium regulation have been studied.When the extracellular calcium concentration was 2.5 mmol/L,either 60 mmol/L KCl,20 mmol/L D-glucose or 0.1 mmol/L tolbutamide induced increase in [Ca2+]i.Such increase in [Ca2+]i was absent when the same stimuli were applied under zero extracellular calcium.These results indicate that the increase of [Ca2+]i is induced by the activation of voltage-dependent calcium channels in β cells.The manifold forms of [Ca2+]i change induced by glucose imply that the effects of glucose are complex.5 mmol/L caffeine or 5 mmol/L MCh increase the [Ca2+]i ,which is independent of the external calcium,suggesting that [Ca2+]i can be regulated by Ca2+ release from not only the IP3-sensitive but also the ryanodine sensitive calcium stores in β cells.The latency of Ca responses for IP3 pathway (5 s) is faster than that for ryanodine pathway (30 s).It is concluded that there are multiple calcium stores in rat pancreatic β cells.

  3. Comparative evaluation of human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite: An in vitro study

    Directory of Open Access Journals (Sweden)

    Sonali Taneja

    2014-01-01

    Full Text Available Introduction: Irrigation plays an indispensable role in removal of tissue remnants and debris from the complicated root canal system. This study compared the human pulp tissue dissolution by different concentrations of chlorine dioxide, calcium hypochlorite and sodium hypochlorite. Materials and Methods: Pulp tissue was standardized to a weight of 9 mg for each sample. In all,60 samples obtained were divided into 6 groups according to the irrigating solution used- 2.5% sodium hypochlorite (NaOCl, 5.25% NaOCl, 5% calcium hypochlorite (Ca(OCl 2 , 10% Ca(OCl 2 , 5%chlorine dioxide (ClO 2 and 13% ClO 2 . Pulp tissue was placed in each test tube carrying irrigants of measured volume (5ml according to their specified subgroup time interval: 30 minutes (Subgroup A and 60 minutes (Subgroup B. The solution from each sample test tube was filtered and was left for drying overnight. The residual weight was calculated by filtration method. Results: Mean tissue dissolution increases with increase in time period. Results showed 5.25% NaOCl to be most effective at both time intervals followed by 2.5% NaOCl at 60 minutes, 10%Ca(OCl 2 and 13% ClO 2 at 60 minutes. Least amount of tissue dissolving ability was demonstrated by 5% Ca(OCl 2 and 5% ClO 2 at 30 minutes. Distilled water showed no pulp tissue dissolution. Conclusion: Withinthe limitations of the study, NaOCl most efficiently dissolved the pulp tissue at both concentrations and at both time intervals. Mean tissue dissolution by Ca(OCl 2 and ClO 2 gradually increased with time and with their increase in concentration.

  4. The calcium-sensing receptor and calcimimetics in blood pressure modulation

    DEFF Research Database (Denmark)

    Smajilovic, Sanela; Yano, Shozo; Jabbari, Reza;

    2011-01-01

    Calcium is a crucial second messenger in the cardiovascular system. However, calcium may also be an extracellular first messenger through a G-protein-coupled receptor that senses extracellular concentration (Ca(2+)(o)), the calcium-sensing receptor (CaR). The most prominent physiological function......R (calcimimetics) are the first drugs in their class to become available for clinical use and have been shown to successfully treat certain forms of primary and secondary hyperparathyroidism. In addition, several studies suggest beneficial effects of calcimimetics on cardiovascular risk factors associated...... with hyperparathyroidism. Although a plethora of studies demonstrated the CaR in heart and blood vessels, exact roles of the receptor in the cardiovascular system still remain to be elucidated. However, several studies point toward a possibility that the CaR might be involved in the regulation of vascular tone...

  5. Factors controlling soil water and stream water aluminum concentrations after a clearcut in a forested watershed with calcium-poor soils

    Science.gov (United States)

    McHale, M.R.; Burns, Douglas A.; Lawrence, G.B.; Murdoch, Peter S.

    2007-01-01

    The 24 ha Dry Creek watershed in the Catskill Mountains of southeastern New York State USA was clearcut during the winter of 1996-1997. The interactions among acidity, nitrate (NO3- ), aluminum (Al), and calcium (Ca2+) in streamwater, soil water, and groundwater were evaluated to determine how they affected the speciation, solubility, and concentrations of Al after the harvest. Watershed soils were characterized by low base saturation, high exchangeable Al concentrations, and low exchangeable base cation concentrations prior to the harvest. Mean streamwater NO3- concentration was about 20 ??mol l-1 for the 3 years before the harvest, increased sharply after the harvest, and peaked at 1,309 ??mol l -1 about 5 months after the harvest. Nitrate and inorganic monomeric aluminum (Alim) export increased by 4-fold during the first year after the harvest. Alim mobilization is of concern because it is toxic to some fish species and can inhibit the uptake of Ca2+ by tree roots. Organic complexation appeared to control Al solubility in the O horizon while ion exchange and possibly equilibrium with imogolite appeared to control Al solubility in the B horizon. Alim and NO3- concentrations were strongly correlated in B-horizon soil water after the clearcut (r2 = 0.96), especially at NO3- concentrations greater than 100 ??mol l-1. Groundwater entering the stream from perennial springs contained high concentrations of base cations and low concentrations of NO3- which mixed with acidic, high Alim soil water and decreased the concentration of Alim in streamwater after the harvest. Five years after the harvest soil water NO 3- concentrations had dropped below preharvest levels as the demand for nitrogen by regenerating vegetation increased, but groundwater NO3- concentrations remained elevated because groundwater has a longer residence time. As a result streamwater NO3- concentrations had not fallen below preharvest levels, even during the growing season, 5 years after the harvest

  6. Glyphosate reduced seed and leaf concentrations of calcium, manganese, magnesium, and iron in non-glyphosate resistant soybean

    OpenAIRE

    ÇAKMAK, İsmail; Cakmak, Ismail; Yazıcı, M. Atilla; YAZICI, M. Atilla; Tutuş, Yusuf; Tutus, Yusuf; ÖZTÜRK, Levent; OZTURK, Levent

    2009-01-01

    Greenhouse experiments were conducted to study the effects of glyphosate drift on plant growth and concentrations of mineral nutrients in leaves and seeds of non-glyphosate resistant soybean plants (Glycine max, L.). Glyphosate was sprayed on plant shoots at increasing rates between 0.06 and 1.2% of the recommended application rate forweed control. In an experiment with 3-week-old plants, increasing application of glyphosate on shoots significantly reduced chlorophyll concentration of the ...

  7. Effet d'un choc hypotonique sur le volume cellulaire et sur la concentration intracellulaire de calcium des cellules branchiales de truite arc-en-ciel

    Directory of Open Access Journals (Sweden)

    LEGUEN I.

    1998-07-01

    Full Text Available La branchie étant un organe à structure complexe, il était impossible d'étudier l'effet d'un choc hypotonique sur les cellules branchiales in situ. Une culture primaire de branchie de truite a donc été mise au point et l'effet d'une dilution du milieu extracellulaire sur ces cellules en culture a été étudié. Les cellules branchiales en culture primaire forment un épithélium à confluence après 5 à 7 jours de culture. Ces cellules présentent les caractéristiques morphologiques des cellules respiratoires de la branchie. Les mesures du volume cellulaire, lors d'un choc hypotonique, sont effectuées sur des populations isolées de cellules respiratoires, à l'aide du système Coulter counter. Lors de la dilution aux 2/3 du milieu externe, les cellules gonflent pour atteindre un volume moyen de 130% en 5 minutes. Ensuite, les cellules régulent lentement leur volume. Après 30 minutes dans les conditions hypotoniques, le gonflement cellulaire ne représente plus que 110% du volume initial. Lors d'un choc hypotonique, nous avons mesuré, à l'aide d'une sonde fluorescente sensible au calcium (le Fura-2, une augmentation de la concentration intracellulaire de calcium des cellules respiratoires en culture primaire.

  8. Reduced Expression of the Extracellular Calcium-Sensing Receptor (CaSR Is Associated with Activation of the Renin-Angiotensin System (RAS to Promote Vascular Remodeling in the Pathogenesis of Essential Hypertension.

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    Yuan-Yuan Qu

    Full Text Available The proliferation of vascular smooth muscle cells (VSMCs, remodeling of the vasculature, and the renin-angiotensin system (RAS play important roles in the development of essential hypertension (EH, which is defined as high blood pressure (BP in which secondary causes, such as renovascular disease, are absent. The calcium-sensing receptor (CaSR is involved in the regulation of BP. However, the underlying mechanisms by which the CaSR regulates BP are poorly understood. In the present study, the role of the CaSR in EH was investigated using male spontaneously hypertensive rats (SHRs and rat and human plasma samples. The percentages of medial wall thickness to external diameter (WT%, total vessel wall cross-sectional area to the total area (WA% of thoracic arteries, as well as the percentage of wall area occupied by collagen to total vessel wall area (CA% were determined. Tissue protein expression and plasma concentrations of the CaSR, cyclic adenosine monophosphate (cAMP, renin, and angiotensin II (Ang II were additionally assessed. WT%, WA%, and CA% were found to increase with increasing BP, whereas the plasma concentration of CaSR was found to decrease. With increasing BP, the levels of smooth muscle actin and calponin decreased, whereas those of osteopontin and proliferating cell nuclear antigen increased. The CaSR level negatively correlated with the levels of cAMP and Ang II, but positively correlated with those of renin. Our data suggest that reduced expression of the CaSR is correlated with activation of the RAS, which induces increased vascular remodeling and VSMC proliferation, and thereby associated with EH in the SHR model and in the Han Chinese population. Our findings provide new insights into the pathogenesis of EH.

  9. Effects of Paper Mill Sludge on Potassium, Sodium, Calcium,and Magnesium Concentrations in Different Soybean Cultivars

    Institute of Scientific and Technical Information of China (English)

    YAN Xiang-Kui; K.W.CHANG; H.L.XU

    2005-01-01

    A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South Korea, to determine the effects of paper mill sludge compost application rates on K, Na, Ca and Mg concentrations of soybean (Glycine max(L.) Merr.) aboveground tissues and the genotypic effects on the concentrations of these elements. Sludge compost treatments of 0, 75, and 150 t ha-1 were applied to 30 diverse soybean cultivars. Concentrations of K, Na, Ca, and Mg in aboveground tissues harvested 69 days after planting (DAP) varied with the genotype and the application rate of paper-mill sludge compost, with the sludge compost application rate exerting stronger influence on these concentrations than the genotype. The magnitude of variation caused by both genotype and sludge compost application was in the order of Mg > K > Ca > Na. Significantly positive correlations were observed between K and Na (P < 0.01), Na and Ca(P < 0.05), and Ca and Mg (P < 0.01). Also, the lower the sludge compost application rate, the larger the variation in the concentrations of K, Na, and Ca. From this several cultivars were identified for use as an accumulator for one or more of these elements.

  10. Influence of tallow and calcium concentrations on the performance and energy and nutrient utilization in broiler starters.

    Science.gov (United States)

    Tancharoenrat, P; Ravindran, V

    2014-06-01

    The influence of tallow and Ca concentrations on the performance, apparent ileal digestibility, and total tract retention of N, Ca, P, and AME in broiler starter diets fed corn-soy-based diets was examined. The experimental design was a 3 × 3 factorial arrangement of treatments evaluating 3 inclusion levels of tallow (0, 40, and 80 g/kg) and 3 dietary concentrations of Ca (7, 10, and 13 g/kg). Nine treatment diets were formulated to meet the requirements for major nutrients for broiler starters, except for AME and Ca concentrations. The results showed that increasing tallow inclusion increased (P 0.05) feed to gain to 10 g/kg of Ca but lower (P tallow, increasing Ca concentrations decreased (P tallow containing 13 g/kg of Ca showed lower (P tallow containing 7 g/kg of Ca showed the lowest (P tallow compared with those with 0 and 80 g/kg of tallow. Birds fed diets containing 7 g/kg of Ca had similar (P > 0.05) fat retention to that of 10 g/kg of Ca, but higher (P tallow containing 7 g/kg of Ca had higher (P tallow diets, 7 g/kg of Ca had the highest (P tallow had the highest ileal digestibility of fat (P tallow compared with those of 0 and 80 g/kg of tallow. High dietary Ca concentrations adversely affected the performance and the utilization of energy, N, Ca, and P in broiler starters.

  11. L-glutamate released from activated microglia downregulates astrocytic L-glutamate transporter expression in neuroinflammation: the ‘collusion’ hypothesis for increased extracellular L-glutamate concentration in neuroinflammation

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    Takaki Junpei

    2012-12-01

    Full Text Available Abstract Background In the central nervous system, astrocytic L-glutamate (L-Glu transporters maintain extracellular L-Glu below neurotoxic levels, but their function is impaired with neuroinflammation. Microglia become activated with inflammation; however, the correlation between activated microglia and the impairment of L-Glu transporters is unknown. Methods We used a mixed culture composed of astrocytes, microglia, and neurons. To quantify L-Glu transporter function, we measured the extracellular L-Glu that remained 30 min after an application of L-Glu to the medium (the starting concentration was 100 μM. We determined the optimal conditions of lipopolysaccharide (LPS treatment to establish an inflammation model without cell death. We examined the predominant subtypes of L-Glu transporters and the changes in the expression levels of these transporters in this inflammation model. We then investigated the role of activated microglia in the changes in L-Glu transporter expression and the underlying mechanisms in this inflammation model. Results Because LPS (10 ng/mL, 72 h caused a significant increase in the levels of L-Glu remaining but did not affect cell viability, we adopted this condition for our inflammation model without cell death. GLAST was the predominant L-Glu transporter subtype, and its expression decreased in this inflammation model. As a result of their release of L-Glu, activated microglia were shown to be essential for the significant decrease in L-Glu uptake. The serial application of L-Glu caused a significant decrease in L-Glu uptake and GLAST expression in the astrocyte culture. The hemichannel inhibitor carbenoxolone (CBX inhibited L-Glu release from activated microglia and ameliorated the decrease in GLAST expression in the inflammation model. In addition, the elevation of the astrocytic intracellular L-Glu itself caused the downregulation of GLAST. Conclusions Our findings suggest that activated microglia trigger the

  12. Neutrophil Extracellular Traps and Microcrystals

    Science.gov (United States)

    2017-01-01

    Neutrophil extracellular traps represent a fascinating mechanism by which PMNs entrap extracellular microbes. The primary purpose of this innate immune mechanism is thought to localize the infection at an early stage. Interestingly, the ability of different microcrystals to induce NET formation has been recently described. Microcrystals are insoluble crystals with a size of 1–100 micrometers that have different composition and shape. Microcrystals have it in common that they irritate phagocytes including PMNs and typically trigger an inflammatory response. This review is the first to summarize observations with regard to PMN activation and NET release induced by microcrystals. Gout-causing monosodium urate crystals, pseudogout-causing calcium pyrophosphate dehydrate crystals, cholesterol crystals associated with atherosclerosis, silicosis-causing silica crystals, and adjuvant alum crystals are discussed. PMID:28373994

  13. Neutrophil Extracellular Traps and Microcrystals.

    Science.gov (United States)

    Rada, Balázs

    2017-01-01

    Neutrophil extracellular traps represent a fascinating mechanism by which PMNs entrap extracellular microbes. The primary purpose of this innate immune mechanism is thought to localize the infection at an early stage. Interestingly, the ability of different microcrystals to induce NET formation has been recently described. Microcrystals are insoluble crystals with a size of 1-100 micrometers that have different composition and shape. Microcrystals have it in common that they irritate phagocytes including PMNs and typically trigger an inflammatory response. This review is the first to summarize observations with regard to PMN activation and NET release induced by microcrystals. Gout-causing monosodium urate crystals, pseudogout-causing calcium pyrophosphate dehydrate crystals, cholesterol crystals associated with atherosclerosis, silicosis-causing silica crystals, and adjuvant alum crystals are discussed.

  14. Neutrophil Extracellular Traps and Microcrystals

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    Balázs Rada

    2017-01-01

    Full Text Available Neutrophil extracellular traps represent a fascinating mechanism by which PMNs entrap extracellular microbes. The primary purpose of this innate immune mechanism is thought to localize the infection at an early stage. Interestingly, the ability of different microcrystals to induce NET formation has been recently described. Microcrystals are insoluble crystals with a size of 1–100 micrometers that have different composition and shape. Microcrystals have it in common that they irritate phagocytes including PMNs and typically trigger an inflammatory response. This review is the first to summarize observations with regard to PMN activation and NET release induced by microcrystals. Gout-causing monosodium urate crystals, pseudogout-causing calcium pyrophosphate dehydrate crystals, cholesterol crystals associated with atherosclerosis, silicosis-causing silica crystals, and adjuvant alum crystals are discussed.

  15. Receptor-like activity evoked by extracellular ADP in Arabidopsis root epidermal plasma membrane.

    Science.gov (United States)

    Demidchik, Vadim; Shang, Zhonglin; Shin, Ryoung; Colaço, Renato; Laohavisit, Anuphon; Shabala, Sergey; Davies, Julia M

    2011-07-01

    Extracellular purine nucleotides are implicated in the control of plant development and stress responses. While extracellular ATP is known to activate transcriptional pathways via plasma membrane (PM) NADPH oxidase and calcium channel activation, very little is known about signal transduction by extracellular ADP. Here, extracellular ADP was found to activate net Ca(2+) influx in roots of Arabidopsis (Arabidopsis thaliana) and transiently elevate cytosolic free Ca(2+) in root epidermal protoplasts. An inward Ca(2+)-permeable conductance in root epidermal PM was activated within 1 s of ADP application and repeated application evoked a smaller current. Such response speed and densitization are consistent with operation of equivalents to animal ionotropic purine receptors, although to date no equivalent genes for such receptors have been identified in higher plants. In contrast to ATP, extracellular ADP did not evoke accumulation of intracellular reactive oxygen species. While high concentrations of ATP caused net Ca(2+) efflux from roots, equivalent concentrations of ADP caused net influx. Overall the results point to a discrete ADP signaling pathway, reliant on receptor-like activity at the PM.

  16. Receptor-Like Activity Evoked by Extracellular ADP in Arabidopsis Root Epidermal Plasma Membrane1

    Science.gov (United States)

    Demidchik, Vadim; Shang, Zhonglin; Shin, Ryoung; Colaço, Renato; Laohavisit, Anuphon; Shabala, Sergey; Davies, Julia M.

    2011-01-01

    Extracellular purine nucleotides are implicated in the control of plant development and stress responses. While extracellular ATP is known to activate transcriptional pathways via plasma membrane (PM) NADPH oxidase and calcium channel activation, very little is known about signal transduction by extracellular ADP. Here, extracellular ADP was found to activate net Ca2+ influx in roots of Arabidopsis (Arabidopsis thaliana) and transiently elevate cytosolic free Ca2+ in root epidermal protoplasts. An inward Ca2+-permeable conductance in root epidermal PM was activated within 1 s of ADP application and repeated application evoked a smaller current. Such response speed and densitization are consistent with operation of equivalents to animal ionotropic purine receptors, although to date no equivalent genes for such receptors have been identified in higher plants. In contrast to ATP, extracellular ADP did not evoke accumulation of intracellular reactive oxygen species. While high concentrations of ATP caused net Ca2+ efflux from roots, equivalent concentrations of ADP caused net influx. Overall the results point to a discrete ADP signaling pathway, reliant on receptor-like activity at the PM. PMID:21562328

  17. Calcium and magnesium concentrations in uterine fluid and blood serum during the estrous cycle in the bovine

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    Sayed Mortaza Alavi-Shoushtari

    2012-06-01

    Full Text Available To investigate uterine and serum Ca++ and Mg++ variations during the estrous cycle in the bovine, 66 genital tracts and blood samples were collected from Urmia abattoir, Urmia, Iran. The phase of the estrous cycle was determined by examination of the structures present on ovaries and uterine tonicity. Of the collected samples, 17 were pro-estrus, 12 estrus, 14 metestrus and 23 diestrus. The uterine fluid was collected by gentle scraping of the uterine mucosa with a curette. The mean ± SEM concentration of serum Ca++ in pro-estrus, estrus, metestrus and diestrus was 5.77 ± 0.69, 8.87 ± 1.83, 10.95 ± 1.52, 11.09 ± 1.08 mg dL-1, and the mean concentration of uterine fluid Ca++ was 4.40 ± 0.72, 3.15 ± 0.67, 5.89 ± 0.88, 8.63 ± 0.97 mg dL-1, respectively. The mean concentration of serum Mg++ in pro-estrus, estrus, metestrus and diestrus was 3.53 ± 0.30, 4.20 ± 0.52, 3.49 ± 0.38, 3.39 ± 0.29 mg dL-1, and mean concentration of uterine fluid Mg++ was 5.27 ± 0.42, 4.92 ± 0.60, 5.56 ± 0.30, 5.88 ± 0.36 mg dL-1, respectively. The serum and uterine fluid Ca++ in pro-estrus were significantly different from those of the metestrus and diestrus. In all stages of estrous cycle the mean concentration of serum Ca++ was higher than that in the uterine fluid. The difference between serum and uterine fluid Ca++ in estrus, metestrus and diestrus was significant. There was no significant difference between serum Mg++ content nor was it different from uterine fluid Mg++ content at any stages of estrous cycle. In all stages of estrous cycle the uterine fluid Mg++ was higher than that of the serum. These results suggest that during the estrous cycle in the cow, Ca++ is passively secreted in uterine fluids and is mostly dependent on blood serum Ca++ variations but Mg++ is secreted independently and does not follow variations in the serum concentrations.

  18. Ecto-nucleoside triphosphate diphosphohydrolase 2 modulates local ATP-induced calcium signaling in human HaCaT keratinocytes.

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    Chia-Lin Ho

    Full Text Available Keratinocytes are the major building blocks of the human epidermis. In many physiological and pathophysiological conditions, keratinocytes release adenosine triphosphate (ATP as an autocrine/paracrine mediator that regulates cell proliferation, differentiation, and migration. ATP receptors have been identified in various epidermal cell types; therefore, extracellular ATP homeostasis likely determines its long-term, trophic effects on skin health. We investigated the possibility that human keratinocytes express surface-located enzymes that modulate ATP concentration, as well as the corresponding receptor activation, in the pericellular microenvironment. We observed that the human keratinocyte cell line HaCaT released ATP and hydrolyzed extracellular ATP. Interestingly, ATP hydrolysis resulted in adenosine diphosphate (ADP accumulation in the extracellular space. Pharmacological inhibition by ARL 67156 or gene silencing of the endogenous ecto-nucleoside triphosphate diphosphohydrolase (NTPDase isoform 2 resulted in a 25% reduction in both ATP hydrolysis and ADP formation. Using intracellular calcium as a reporter, we found that although NTPDase2 hydrolyzed ATP and generated sustainable ADP levels, only ATP contributed to increased intracellular calcium via P2Y2 receptor activation. Furthermore, knocking down NTPDase2 potentiated the nanomolar ATP-induced intracellular calcium increase, suggesting that NTPDase2 globally attenuates nucleotide concentration in the pericellular microenvironment as well as locally shields receptors in the vicinity from being activated by extracellular ATP. Our findings reveal an important role of human keratinocyte NTPDase2 in modulating nucleotide signaling in the extracellular milieu of human epidermis.

  19. Calcium dependent magnesium uptake in myocardium.

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    Bianchi, C P; Liu, D

    1993-01-01

    The frog myocardium maintains magnesium content at a steady state level when stimulated at 0.4Hz while being perfused with Ringer's solution containing 1 x 10(-3) M Ca2+ and 5 x 10(-7) M magnesium. When calcium is removed 43% of tissue magnesium is lost within 30 seconds or 12 beats. Restoration of calcium to the perfusion solution causes reaccumulation of magnesium from a solution containing 5 x 10(-7) M magnesium. The reaccumulation of magnesium indicates a highly selective transport system for magnesium which is dependent upon the presence of calcium. Calcium appears to reduce the leak of magnesium from the myocardium and enhances the transport of magnesium into the myocardial cell. Intracellular magnesium is a necessary cofactor for hundreds of enzymes, and is essential for protein synthesis and as an extracellular divalent cation helps to stabilize excitable membranes in conjunction with calcium. The concentration of ionized magnesium in the sarcoplasm of myocardial muscle has an average value of 1.45 mM +/- 1.37 (standard deviation), N = 19) with a range of 0.5 to 3.6 mM (1). The heart with its numerous mitochondria and high enzymatic activity is vulnerable to myocardial damage due to magnesium loss. The isolated frog ventricle conserves intracellular magnesium when perfused with Ringer's solution containing no added magnesium and maintains function for hours. The ability to conserve magnesium suggests a low permeability of the sarcolemma to magnesium and an extremely efficient inward transport system. Removal of calcium as well as magnesium from the perfusion solution causes a rapid loss of tension in the electrically driven frog ventricle (0.4) Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Control of the light-regulated current in rod photoreceptors by cyclic GMP, calcium, and l-cis-diltiazem.

    Science.gov (United States)

    Stern, J H; Kaupp, U B; MacLeish, P R

    1986-02-01

    The effect of calcium ions on the cGMP-activated current of outer segment membrane was examined by the excised-patch technique. Changes in the extracellular calcium concentration had marked effects on the cGMP-activated current, while changes in intracellular calcium concentration were ineffective. Changes in calcium concentration in the absence of cGMP had little, if any, effect on membrane conductance. These results suggest that both intracellular cGMP and extracellular calcium can directly affect the conductance underlying the light response in rod cells. The pharmacological agent l-cis-diltiazem reversibly inhibited the cGMP-activated current when applied to the intracellular side of an excised patch. When superfused over intact rod cells, l-cis-diltiazem reversibly blocked much of the normal light response. The isomer, d-cis-diltiazem, did not significantly affect either patches or intact rod cells. Thus, the light-regulated conductance has binding sites for both calcium and cGMP that may interact during the normal light response in rod cells and a site specific for l-cis-diltiazem that can be used to identify and further study the conductance mechanism.

  1. Calcium mobilisation following shell damage in the Pacific oyster, Crassostrea gigas.

    Science.gov (United States)

    Sillanpää, J K; Ramesh, K; Melzner, F; Sundh, H; Sundell, K

    2016-06-01

    Shell growth of oysters requires calcium uptake from the environment and transport to the area of shell formation. A shell regeneration assay in combination with radiolabelled calcium was used to investigate uptake and distribution of calcium to different tissues and hemolymph fractions in Pacific oysters, Crassostrea gigas (Bivalvia, Ostreoida). Oysters were notched at the shell margin and subsequently sampled for hemolymph and grading of shell regeneration during a two week experimental period. Half of the oysters were additionally exposed to (45)Ca and sampled for hemolymph and tissues. Total plasma calcium concentrations increased in notched oysters compared to controls on 1, 2 and 7days after notching. A decrease in plasma calcium levels was apparent on day 4, for both total and ionic calcium. The shell regeneration assay in the notched oysters resulted in a visible deposition of CaCO3 onto the regenerate from day 7 onwards. This was coinciding with an increased uptake of total calcium on days 11 and 14 as well as free, i.e. ionic and ligand-bound calcium, on day 14. At day 1, notching also increased calcium uptake into the mantle tissues, in areas above the notch and near the hinge. During the experiment, both the total hemocyte count and the number of granulocytes increased in notched compared to control oysters. The present study suggests that induced shell damage results in a dynamic regulation of the calcium uptake from the environment and the distribution of calcium within the body, starting directly after notching. Increases in both total calcium concentrations and uptake rates coincided with the visible depositions of CaCO3 on the regenerate shell. C. gigas was found to transport calcium mainly in the ionic form in the hemolymph, with only minor parts being bound to proteins or smaller ligands. Hemolymph measurement also revealed that C. gigas is able to regulate the extracellular concentrations of calcium and potassium. The changes in plasma calcium

  2. Endothelin induces two types of contractions of rat uterus: phasic contractions by way of voltage-dependent calcium channels and developing contractions through a second type of calcium channels

    Energy Technology Data Exchange (ETDEWEB)

    Kozuka, M.; Ito, T.; Hirose, S.; Takahashi, K.; Hagiwara, H.

    1989-02-28

    Effects of endothelin on nonvascular smooth muscle have been examined using rat uterine horns and two modes of endothelin action have been revealed. Endothelin (0.3 nM) caused rhythmic contractions of isolated uterus in the presence of extracellular calcium. The rhythmic contractions were completely inhibited by calcium channel antagonists. These characteristics of endothelin-induced contractions were very similar to those induced by oxytocin. Binding assays using /sup 125/I-endothelin showed that endothelin and the calcium channel blockers did not compete for the binding sites. However, endothelin was unique in that it caused, in addition to rhythmic contractions, a slowly developing monophasic contraction that was insensitive to calcium channel blockers. This developing contraction became dominant at higher concentrations of endothelin and was also calcium dependent.

  3. Submicromolar concentrations of zinc irreversibly reduce a calcium-dependent potassium current in rat hippocampal neurons in vitro.

    Science.gov (United States)

    Sim, J A; Cherubini, E

    1990-01-01

    The action of the endogenous divalent cation zinc on Ca2+ and Ca2(+)-dependent currents was studied in rat hippocampal CA1 and CA3 neurons in vitro, by means of a single electrode voltage clamp technique. Bath application of zinc (0.5-1 microM) produced a small membrane depolarization associated with an increase in synaptic noise and cell excitability and a depression of the afterhyperpolarization following a train of action potentials. The effects on the afterhyperpolarization, could not be reversed on washout. In voltage-clamped neurons, zinc induced a steady inward current and reduced, at resting membrane potential, the peak amplitude of the outward current underlying the afterhyperpolarization, IAHP. In caesium loaded neurons (in the presence of tetrodotoxin and tetraethylammonium), zinc reduced the slow inactivating Ca2+ current activated from a holding potential of -40 mV. Similar results were observed with nickel and cobalt at comparable concentrations, with Zn2+ greater than Ni2+ greater than Co2+, in their order of potency. In contrast to nickel and cobalt the effects of zinc did not reverse on washout. These results suggest that low concentrations of zinc enhance cell excitability by reducing IAHP. In addition, zinc reduces the slow inactivating voltage-dependent Ca2+ current. The irreversible effect of this metal ion is compatible with a toxic, intracellular site of action.

  4. Connections between connexins, calcium, and cataracts in the lens.

    Science.gov (United States)

    Gao, Junyuan; Sun, Xiurong; Martinez-Wittinghan, Francisco J; Gong, Xiaohua; White, Thomas W; Mathias, Richard T

    2004-10-01

    There is a good deal of evidence that the lens generates an internal micro circulatory system, which brings metabolites, like glucose, and antioxidants, like ascorbate, into the lens along the extracellular spaces between cells. Calcium also ought to be carried into the lens by this system. If so, the only path for Ca2+ to get out of the lens is to move down its electrochemical gradient into fiber cells, and then move by electrodiffusion from cell to cell through gap junctions to surface cells, where Ca-ATPase activity and Na/Ca exchange can transport it back into the aqueous or vitreous humors. The purpose of the present study was to test this calcium circulation hypothesis by studying calcium homeostasis in connexin (Cx46) knockout and (Cx46 for Cx50) knockin mouse lenses, which have different degrees of gap junction coupling. To measure intracellular calcium, FURA2 was injected into fiber cells, and the gradient in calcium concentration from center to surface was mapped in each type of lens. In wild-type lenses the coupling conductance of the mature fibers was approximately 0.5 S/cm2 of cell to cell contact, and the best fit to the calcium concentration data varied from 700 nM in the center to 300 nM at the surface. In the knockin lenses, the coupling conductance was approximately 1.0 S/cm2 and calcium varied from approximately 500 nM at the center to 300 nM at the surface. Thus, when the coupling conductance doubled, the concentration gradient halved, as predicted by the model. In knockout lenses, the coupling conductance was zero, hence the efflux path was knocked out and calcium accumulated to approximately 2 microM in central fibers. Knockout lenses also had a dense central cataract that extended from the center to about half the radius. Others have previously shown that this cataract involves activation of a calcium-dependent protease, Lp82. We can now expand on this finding to provide a hypothesis on each step that leads to cataract formation: knockout of

  5. Elevated tonic extracellular dopamine concentration and altered dopamine modulation of synaptic activity precede dopamine loss in the striatum of mice overexpressing human α-synuclein.

    Science.gov (United States)

    Lam, Hoa A; Wu, Nanping; Cely, Ingrid; Kelly, Rachel L; Hean, Sindalana; Richter, Franziska; Magen, Iddo; Cepeda, Carlos; Ackerson, Larry C; Walwyn, Wendy; Masliah, Eliezer; Chesselet, Marie-Françoise; Levine, Michael S; Maidment, Nigel T

    2011-07-01

    Overexpression or mutation of α-synuclein (α-Syn), a protein associated with presynaptic vesicles, causes familial forms of Parkinson's disease in humans and is also associated with sporadic forms of the disease. We used in vivo microdialysis, tissue content analysis, behavioral assessment, and whole-cell patch clamp recordings from striatal medium-sized spiny neurons (MSSNs) in slices to examine dopamine transmission and dopaminergic modulation of corticostriatal synaptic function in mice overexpressing human wild-type α-Syn under the Thy1 promoter (α-Syn mice). Tonic striatal extracellular dopamine and 3-methoxytyramine levels were elevated in α-Syn mice at 6 months of age, prior to any reduction in total striatal tissue content, and were accompanied by an increase in open-field activity. Dopamine clearance and amphetamine-induced dopamine efflux were unchanged. The frequency of MSSN spontaneous excitatory postsynaptic currents (sEPSCs) was lower in α-Syn mice. Amphetamine reduced sEPSC frequency in wild types (WTs) but produced no effect in α-Syn mice. Furthermore, whereas quinpirole reduced and sulpiride increased sEPSC frequency in WT mice, they produced the opposite effects in α-Syn mice. These observations indicate that overexpression of α-Syn alters dopamine efflux and D2 receptor modulation of corticostriatal glutamate release at a young age. At 14 months of age, the α-Syn mice presented with significantly lower striatal tissue dopamine and tyrosine hydroxylase content relative to WT littermates, accompanied by an L-DOPA-reversible sensory motor deficit. Together, these data further validate this transgenic mouse line as a slowly progressing model of Parkinson's disease and provide evidence for early dopamine synaptic dysfunction prior to loss of striatal dopamine. Copyright © 2011 Wiley-Liss, Inc.

  6. Force-dependent calcium signaling and its pathway of human neutrophils on P-selectin in flow.

    Science.gov (United States)

    Huang, Bing; Ling, Yingchen; Lin, Jiangguo; Du, Xin; Fang, Ying; Wu, Jianhua

    2017-02-01

    P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.

  7. The effects of thermal stimuli on intracellular calcium change and histamine releases in rat basophilic leukemia mast cells

    Science.gov (United States)

    Wu, Zu-Hui; Zhu, Dan; Chen, Ji-Yao; Zhou, Lu-Wei

    2012-05-01

    The effects of thermal stimuli on rat basophilic leukemia mast cells were studied. The cells in calcium-contained or calcium-free buffers were thermally stimulated in the temperature range of 25-60 °C. The corresponding calcium ion concentration in cells [Ca2+]i as well as the released histamine from cells was measured with fluorescence staining methods. The ruthenium red (RR), a block of membrane calcium channels (transient receptor potential family V (TRPV)), was used in experiments. Under the stimulus of 25-50 °C, no significant difference on [Ca2+]i was found between these three groups of the cells in calcium-contained buffer without or with RR and cells in calcium-free saline, indicating that the increased calcium in cytosol did not result from the extracellular buffer but came from the intracellular calcium stores. The [Ca2+]i continuously increased under the temperature of 50-60 °C, but the RR and calcium-free saline can obviously diminish the [Ca2+]i increase at these high temperatures, reflecting that the opening of the TRPV2 channels leads to a calcium influx resulting in the [Ca2+]i increment. The histamine release also became significant in these cases. Since the released histamine is a well-known mediator for the microcirculation promotion, the histamine release from mast cells could be one of the mechanisms of thermal therapy.

  8. Non-GABA(A)-mediated effects of lindane on neurite development and intracellular free calcium ion concentration in cultured rat hippocampal neurons.

    Science.gov (United States)

    Ferguson, C A; Audesirk, G

    1995-04-01

    Changes in transmembrane Ca(2+) fluxes and intracellular free Ca(2+) ion concentrations ([Ca(2+)](in)) regulate many aspects of neurite development in cultured neurons. Lindane has been shown to increase [Ca(2+)](in) in several cell types. It was therefore hypothesized that lindane exposure would increase [Ca(2+)](in) and thereby alter neurite development in cultured rat hippocampal neurons. The study reported here showed that lindane (50-100 muM) increased [Ca(2+)](in) during short-term exposure (up to 4 hr); in contrast, with long-term exposure (24-48 hr) lindane (1-50 mum) decreased [Ca(2+)](in) significantly below control levels. Lindane decreased neurite initiation at high concentrations (25 mum or above). Lindane increased dendrite number at low concentrations (0.5-1 muM), but decreased dendrite number at high concentrations (50 mum or above). Lindane decreased axon and dendrite elongation and branching at 50 mum. Loading neurons with 1 mum 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), a calcium chelator that partially 'clamps' [Ca(2+)](in), eliminated the effects of 50 mum lindane on [Ca(2+)](in) in short-term exposures. BAPTA did not significantly reverse the inhibition of neurite initiation or axonal elongation caused by 50 mum lindane. However, BAPTA partially reversed the inhibition of dendrite elongation and completely reversed the inhibition of axon and dendrite branching caused by 50 mum lindane. Therefore, some, but not all, of lindane's effects on neurite development may be due to changes in [Ca(2+)](in). Picrotoxin, a gamma-aminobutyric acid A (GABA(A))-associated chloride channel antagonist, had no effect on [Ca(2+)](in) or any parameters of neurite growth, suggesting that the effects of lindane on neurite development and [Ca(2+)](in) were not mediated through actions on GABA(A)-associated chloride channels.

  9. The impact of calcium current reversal on neurotransmitter release in the electrically stimulated retina

    Science.gov (United States)

    Werginz, Paul; Rattay, Frank

    2016-08-01

    Objective. In spite of intense theoretical and experimental investigations on electrical nerve stimulation, the influence of reversed ion currents on network activity during extracellular stimulation has not been investigated so far. Approach. Here, the impact of calcium current reversal on neurotransmitter release during subretinal stimulation was analyzed with a computational multi-compartment model of a retinal bipolar cell (BC) that was coupled with a four-pool model for the exocytosis from its ribbon synapses. Emphasis was laid on calcium channel dynamics and how these channels influence synaptic release. Main results. Stronger stimulation with anodic pulses caused transmembrane voltages above the Nernst potential of calcium in the terminals and, by this means, forced calcium ions to flow in the reversed direction from inside to the outside of the cell. Consequently, intracellular calcium concentration decreased resulting in a reduced vesicle release or preventing release at all. This mechanism is expected to lead to a pronounced ring-shaped pattern of exocytosis within a group of neighbored BCs when the stronger stimulated cells close to the electrode fail in releasing vesicles. Significance. Stronger subretinal stimulation causes failure of synaptic exocytosis due to reversal of calcium flow into the extracellular space in cells close to the electrode.

  10. Collective Calcium Signaling of Defective Multicellular Networks

    Science.gov (United States)

    Potter, Garrett; Sun, Bo

    2015-03-01

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

  11. Extracellular calmodulin: A polypeptide signal in plants?

    Institute of Scientific and Technical Information of China (English)

    SUN; Daye(

    2001-01-01

    [1]Cheng. W. Y., Cyclic 3', 5'-nucleotide phosphodiestrase: demonstration of an activator, Biochm. Biophys. Res. Commun.,1970, 38: 533-538.[2]Boynton, A. L., Whitfield, J. F., MacManus, J. P., Calmodulin stimulates DNA synthesis by rat liver cells, BBRC.1980,95(2): 745-749.[3]Gorbacherskaya, L. V., Borovkova, T. V., Rybin, U. O. et al., Effect of exogenous calmodulin on lymphocyte proliferation in normal subjects, Bull Exp. Med. Biol., 1983, 95: 361-363.[4]Wong, P. Y.-K., Lee, W. H., Chao, PH.-W., The role of calmodulin in prostaglandin metabolism, Ann. NY Acad. Sci.,1980, 356: 179-189.[5]Mac Neil, S., Dawson, R. A., Crocker, G. et al., Effects of extracellular calmodulin and calmodulin antagonists on B16 melanoma cell growth, J. Invest. Dermatol., 1984, 83: 15-19.[6]Crocker, D. G., Dawson, R. A., Mac Neil, S. et al., An extracellular role for calmodulin-like activity in cell proliferation,Biochem. J., 1988, 253: 877-884.[7]Polito. V. S., Calmodulin and calmodulin inhibitors: effect on pollen germination and tube growth, in Pollen: Biology and Implications for Plant Breeding (eds. Mulvshy, D. L., Ottaviaro, E.), New York: Elsevier, 1983.53-60.[8]Biro, R. L., Sun, D. Y., Roux, S. J.et al., Characterization of oat calmodulin and radioimmunoassay of its subcellular distribution, Plant Physiol., 1984,75: 382-386.[9]Terry, M. E., Bonner, B. A., An examination of centrifugation as a method of extracting an extracellular solution from peas, and its use for the study of IAA-induced growth, Plant Physiol., 1980, 66: 321-325.[10]Josefina, H. N., Aldasars, J. J., Rodriguez, D., Localization of calmodulin on embryonic Cice aricium L, in Molecular and Cellular Aspects of Calcium in Plant Development (ed. Trewavas, A. J.), New York, London: Plenum Press, 1985, 313.[11]Dauwalder, M., Roux, S. J., Hardison, L., Distribution of calmodulin in pea seedling: immunocytochemical localization in plumules and root apices, Planta, 1986, 168: 461

  12. Effect of concentrating and exposing the bioluminescent bacteria to the non-luminescent allo-bacterial extracellular products on their luminescence

    Digital Repository Service at National Institute of Oceanography (India)

    Ravindran, J.; Priya, G.G.; Kannapiran, E.

    of cell-cell physical contact will be high. In this study, the physical proximity was artificially enhanced between cells and the effect on luminescence in the concentrated cells in the normal culture medium and in the presence of other non-bacterial cell...

  13. T-type voltage-gated calcium channels regulate the tone of mouse efferent arterioles

    DEFF Research Database (Denmark)

    Poulsen, Christian B; Al-Mashhadi, Rozh H; Cribbs, Leanne L;

    2011-01-01

    Voltage-gated calcium channels are important for the regulation of renal blood flow and the glomerular filtration rate. Excitation-contraction coupling in afferent arterioles is known to require activation of these channels and we studied their role in the regulation of cortical efferent arteriolar...... tone. We used microdissected perfused mouse efferent arterioles and found a transient vasoconstriction in response to depolarization with potassium; an effect abolished by removal of extracellular calcium. The T-type voltage-gated calcium channel antagonists mibefradil and nickel blocked this potassium....... Low concentrations of nickel, an agent that blocks Ca(v)3.2, had a similar effect. Thus, T-type voltage-gated calcium channels are functionally important for depolarization-induced vasoconstriction and subsequent dilatation in mouse cortical efferent arterioles.Kidney International advance online...

  14. In SYNC: The ins and outs of circadian oscillations in calcium

    OpenAIRE

    Imaizumi, Takato; Julian I Schroeder; Kay, Steve A.

    2007-01-01

    Many stimuli induce short-term increases in the cytosolic concentration of free calcium ions (Ca2+) that encode signaling information about diverse physiological and developmental events. Slow cytosolic Ca2+ oscillations that span an entire day have also been discovered in both plants and animals; it is thought that these daily Ca2+ oscillations may encode circadian clock signaling information. A recent study focusing on the characterization of the extracellular Ca2+-sensing receptor (CAS) ha...

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

    DEFF Research Database (Denmark)

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

    2003-01-01

    of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx......43 (UMR/Cx43) we confirmed that nifedipine sensitivity of ICW required Cx43 expression. In human osteoblastic cells, gap junction-dependent ICW also required activation of L-type calcium channels and influx of extracellular calcium....

  16. Effect of concentrating and exposing the bioluminescent bacteria to the non-luminescent allo-bacterial extracellular products on their luminescence.

    Science.gov (United States)

    Ravindran, J; Geetha Priya, G; Kannapiran, E

    2011-01-01

    Bioluminescence is a biochemical process occurring in many organisms. Bacterial bioluminescence has been investigated extensively that lead to many applications of such knowledge. Quorum sensing in the bioluminescent bacteria is a chemical signal process to recognize the strength of its own population to start luminescence in harmony. There is a mechanism in these bacteria to also recognize inter-species strength. When there is a higher number of these bacteria, the possibility and frequency of cell-cell physical contact will be high. In this study, the physical proximity was artificially enhanced between cells and the effect on luminescence in the concentrated cells in the normal culture medium and in the presence of other non-bacterial cell-free supernatants was investigated. The role of such physical contact in the quorum sensing in the bioluminescence is not known. Increase in the luminescence of V. fischeri when concentrated shows that the presence of physical proximity facilitates the quorum sensing for their bioluminescence.

  17. Relationship between tap water hardness, magnesium, and calcium concentration and mortality due to ischemic heart disease or stroke in The Netherlands.

    Science.gov (United States)

    Leurs, Lina J; Schouten, Leo J; Mons, Margreet N; Goldbohm, R Alexandra; van den Brandt, Piet A

    2010-03-01

    Conflicting results on the relationship between the hardness of drinking water and mortality related to ischemic heart disease (IHD) or stroke have been reported. We investigated the possible association between tap water calcium or magnesium concentration and total hardness and IHD mortality or stroke mortality. In 1986, a cohort of 120,852 men and women aged 5569 years provided detailed information on dietary and other lifestyle habits. Follow-up for mortality until 1996 was established by linking data from the Central Bureau of Genealogy and Statistics Netherlands. We calculated tap water hardness for each postal code using information obtained from all pumping stations in the Netherlands. Tap water hardness was categorized as soft [hard (1.62.0 mmol/L CaCO3), and hard (> 2.0 mmol/L CaCO3). The multivariate case-cohort analysis was based on 1,944 IHD mortality and 779 stroke mortality cases and 4,114 subcohort members. For both men and women, we observed no relationship between tap water hardness and IHD mortality [hard vs. soft water: hazard ratio (HR) = 1.03; 95% confidence interval (CI), 0.851.28 for men and HR = 0.93; 95% CI, 0.711.21 for women) and stroke mortality (hard vs. soft water HR = 0.90; 95% CI, 0.661.21 and HR = 0.86; 95% CI, 0.621.20, respectively). For men with the 20% lowest dietary magnesium intake, an inverse association was observed between tap water magnesium intake and stroke mortality (HR per 1 mg/L intake = 0.75; 95% CI, 0.610.91), whereas for women with the 20% lowest dietary magnesium intake, the opposite was observed. We found no evidence for an overall significant association between tap water hardness, magnesium or calcium concentrations, and IHD mortality or stroke mortality. More research is needed to investigate the effect of tap water magnesium on IHD mortality or stroke mortality in subjects with low dietary magnesium intake.

  18. Effect of a novel microbial phytase on production performance and tibia mineral concentration in broiler chickens given low-calcium diets.

    Science.gov (United States)

    Singh, A; Walk, C L; Ghosh, T K; Bedford, M R; Haldar, S

    2013-01-01

    1. In a 42-d feeding trial, 264 one-d-old, as hatched, Cobb 400 broiler chickens (6 pens per group, n = 11 per pen in a 2 × 2 factorial arrangement) were fed on two concentrations of dietary calcium (Ca) (9.0 and 7.5 g/kg in starter, 7.5 and 6 g/kg in grower phases) and supplemental phytase (0 and 500 U/kg diet). 2. During d 0-21, the high Ca + phytase diet improved body weight. During d 0-42, feed intake was increased by the low Ca diet and decreased by phytase supplementation. Feed conversion ratio during d 0-21 was improved by the high Ca + phytase diet. 3. At d 42, Ca in duodenal digesta was reduced by low dietary Ca and supplemental phytase. High dietary Ca reduced P in duodenal and jejunal digesta. Phytase reduced digesta P and increased serum P concentration. 4. Relative tibia length decreased with low dietary Ca and increased with phytase. The robusticity index of tibia was improved by the low Ca diet and phytase supplementation. Phytase supplementation increased tibia ash and concentrations of Ca, magnesium (Mg), manganese (Mn), copper (Cu), zinc (Zn) and iron (Fe) in tibia. The low Ca diet increased Mg, Mn and Fe and reduced Cu and Zn in tibia. 5. It was concluded that 7.5 g Ca/kg during weeks 0-3 and 6 g Ca/kg during weeks 3-6 sustained broiler performance and bone ash, while phytase supplementation facilitated tibia mineralisation, particularly during the grower phase.

  19. The effects of secular calcium and magnesium concentration changes on the thermodynamics of seawater acid/base chemistry: Implications for Eocene and Cretaceous ocean carbon chemistry and buffering

    Science.gov (United States)

    Hain, Mathis P.; Sigman, Daniel M.; Higgins, John A.; Haug, Gerald H.

    2015-05-01

    Reconstructed changes in seawater calcium and magnesium concentration ([Ca2+], [Mg2+]) predictably affect the ocean's acid/base and carbon chemistry. Yet inaccurate formulations of chemical equilibrium "constants" are currently in use to account for these changes. Here we develop an efficient implementation of the MIAMI Ionic Interaction Model to predict all chemical equilibrium constants required for carbon chemistry calculations under variable [Ca2+] and [Mg2+]. We investigate the impact of [Ca2+] and [Mg2+] on the relationships among the ocean's pH, CO2, dissolved inorganic carbon (DIC), saturation state of CaCO3 (Ω), and buffer capacity. Increasing [Ca2+] and/or [Mg2+] enhances "ion pairing," which increases seawater buffering by increasing the concentration ratio of total to "free" (uncomplexed) carbonate ion. An increase in [Ca2+], however, also causes a decline in carbonate ion to maintain a given Ω, thereby overwhelming the ion pairing effect and decreasing seawater buffering. Given the reconstructions of Eocene [Ca2+] and [Mg2+] ([Ca2+]~20 mM; [Mg2+]~30 mM), Eocene seawater would have required essentially the same DIC as today to simultaneously explain a similar-to-modern Ω and the estimated Eocene atmospheric CO2 of ~1000 ppm. During the Cretaceous, at ~4 times modern [Ca2+], ocean buffering would have been at a minimum. Overall, during times of high seawater [Ca2+], CaCO3 saturation, pH, and atmospheric CO2 were more susceptible to perturbations of the global carbon cycle. For example, given both Eocene and Cretaceous seawater [Ca2+] and [Mg2+], a doubling of atmospheric CO2 would require less carbon addition to the ocean/atmosphere system than under modern seawater composition. Moreover, increasing seawater buffering since the Cretaceous may have been a driver of evolution by raising energetic demands of biologically controlled calcification and CO2 concentration mechanisms that aid photosynthesis.

  20. Mitochondrial response and calcium ion change in apoptotic insect cells induced by SfaMNPV

    Institute of Scientific and Technical Information of China (English)

    XIU Meihong; PENG Jianxin; HONG Huazhu

    2005-01-01

    Mitochondrial responses and changes of calcium ions in apoptotic insect SL-1 cells induced by Syngrapha falcifera multiple nuclear polyhedrosis virus (SfaMNPV) are reported in this paper. By using Rhodamine 123 as a fluorescent labeling probe, flow cytometry analysis and confocal laser scanning microscope observation we observed that the mitochondrial transmembrane potential (△Ψm) began to decrease in SL-1 cells at 4 h post infection and △Ψm reduced continuously with the extension of virus infection. Western blotting indicated that the Bcl-2 level in the mitochondria gradually declined and was down- regulated. Cells undergoing apoptosis were found to have an elevation of cytochrome c in the cytosol and a corresponding decrease in the mitochondria, which indicated that cytochrome c was released from mitochondria into cytosol. These results suggest that mitochondrion-mediated apoptotic signal transduction pathway exists in apoptotic insect cell induced by SfaMNPV. Cytosolic free calcium ([Ca2+]i) concentration rapidly increased after SfaMNPV infection and the elevated calcium was tested to come partly from extracelllular calcium ion influx. Flow cytometry analysis indicated that the apoptosis in SL-1 cells was not influenced by established cytosolic calcium clamped conditions and the EGTA inhibiting calcium influx. Therefore, neither the elevation of cytosolic calcium ion nor extracellular calcium entry was the inducing factor of apoptosis, which hinted that the depletion of ER Ca2+ store contributed to SL-1 cell apoptosis induced by SfaMNPV.

  1. Predictive value of derived calcium figures based on the measurement of ionised calcium.

    Science.gov (United States)

    Gardner, M D; Dryburgh, F J; Fyffe, J A; Jenkins, A S

    1981-03-01

    The algorithms used in this hospital to assess calcium status are calculated ionised serum calcium and the serum calcium concentration adjusted for albumin. In order to establish their clinical usefulness, they were compared with the ionised calcium concentration measured on the Nova 2 instrument in patients with various calcium and protein abnormalities. Good correlation was found between the measured and calculated values. The predictive values for the calculated results and for total serum calcium concentrations are presented. In this series, the derived values were useful in predicting the serum ionised calcium concentration of the patients studied.

  2. The tyrosyl-tRNA synthetase like gene located in the tyramine biosynthesis cluster of Enterococcus durans is transcriptionally regulated by tyrosine concentration and extracellular pH

    Directory of Open Access Journals (Sweden)

    Linares Daniel M

    2012-02-01

    Full Text Available Abstract Background The tyramine producer Enterococcus durans IPLA655 contains all the necessary genes for tyramine biosynthesis, grouped in the TDC cluster. This cluster includes tyrS, an aminoacyl-tRNA synthetase like gene. Results This work shows that tyrS was maximally transcribed in absence of tyrosine at acidic pH, showing a greater than 10-fold induction in mRNA levels over levels occurring in presence of tyrosine. Mapping of the tyrS transcriptional start site revealed an unusually long untranslated leader region of 322 bp, which displays the typical features of the T box transcriptional attenuation mechanism. The tyrosine concentration regulation of tyrS was found to be mediated by a transcription antitermination system, whereas the specific induction at acidic pH was regulated at transcription initiation level. Conclusions The expression of the tyrS gene present in the TDC cluster of E. durans is transcriptionally regulated by tyrosine concentration and extracelular pH. The regulation is mediated by both an antitermination system and the promoter itself.

  3. Aryl hydrocarbon receptor-independent up-regulation of intracellular calcium concentration by environmental polycyclic aromatic hydrocarbons in human endothelial HMEC-1 cells.

    Science.gov (United States)

    Mayati, Abdullah; Le Ferrec, Eric; Lagadic-Gossmann, Dominique; Fardel, Olivier

    2012-09-01

    Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) constitute a major family of widely-distributed environmental toxic contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). B(a)P has been recently shown to trigger an early and transient increase of intracellular calcium concentration ([Ca(2+)](i)), involved in AhR-related up-regulation of target genes by B(a)P. This study was designed to determine whether AhR may play a role in [Ca(2+)](i) induction provoked by B(a)P. We demonstrated that, in addition to B(a)P, various PAHs, including pyrene and benzo(e)pyrene, known to not or only very poorly interact with AhR, similarly up-regulated [Ca(2+)](i) in human endothelial HMEC-1 cells. Moreover, α-naphthoflavone, a flavonoïd antagonist of AhR, was also able to induce [Ca(2+)](i). Knocking-down AhR expression in HMEC-1 cells through transfection of siRNAs, was finally demonstrated to not prevent B(a)P-mediated induction of [Ca(2+)](i), whereas it efficiently counteracted B(a)P-mediated induction of the referent AhR target gene cytochrome P-450 1B1. Taken together, these data demonstrate that environmental PAHs trigger [Ca(2+)](i) induction in an AhR-independent manner.

  4. Increased osteoinductivity and mineralization by minimal concentration of bone morphogenetic protein-2 loaded onto biphasic calcium phosphate in a rabbit sinus

    Science.gov (United States)

    2016-01-01

    Purpose The purpose of the present study was to evaluate the effectiveness of a minimal concentration of bone morphogenetic protein-2 (BMP-2) in terms of quantitative and qualitative analyses of newly formed bone in a rabbit maxillary sinus model. Methods In 7 rabbits, sinus windows were prepared bilaterally. Biphasic calcium phosphate (BCP) loaded with 0.05 mg/mL BMP-2 was grafted into one sinus (the BMP group) and saline-soaked BCP was placed into the other (the control group) in each animal. The animals were allowed an 8-week healing period before being sacrificed. Specimens including the augmented area and surrounding tissues were then removed and evaluated both radiographically and histologically. Results There was a difference in the mineralization of new bone between the groups. In the BMP group, the greater part of the new bone consisted of mature lamellar bone with an evident trabecular pattern, whereas the control group showed mostly woven bone, consisting only partially of lamellar bone. Histometrically, the area of new bone was significantly greater (4.55±1.35 mm2 vs. 2.99±0.86 mm2) in the BMP group than in the control group (Pmineralization in a rabbit sinus model using a BCP carrier. PMID:27800217

  5. Spectroscopic Characterization of Extracellular Polymeric Substances from Escherichia coli and Serratia marcescens: Suppression using Sub-Inhibitory Concentrations of Bismuth Thiols

    Energy Technology Data Exchange (ETDEWEB)

    Badireddy, Appala R.; Korpol, Bhoom Reddy; Chellam, Shankararaman; Gassman, Paul L.; Engelhard, Mark H.; Lea, Alan S.; Rosso, Kevin M.

    2008-10-21

    Free and capsular EPS produced by Escherichia coli and Serratia marcescens were characterized in detail using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES). Total EPS production decreased upon treatment with sub-inhibitory concentrations of lipophilic bismuth thiols (bismuth dimercaptopropanol, BisBAL; bismuth ethanedithiol, BisEDT; and bismuth pyrithione, BisPYR), BisBAL being most effective. Bismuth thiols also influenced acetylation and carboxylation of polysaccharides in EPS from S. marcescens. Extensive homology between EPS samples in the presence and absence of bismuth was observed with proteins, polysaccharides, and nucleic acids varying predominantly only in the total amount expressed. Second derivative analysis of the amide I region of FTIR spectra revealed decreases in protein secondary structures in the presence of bismuth thiols. Hence, anti-fouling properties of bismuth thiols appear to originate in their ability to suppress O-acetylation and protein secondary structures in addition to total EPS secretion.

  6. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

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

  7. Effects of Arecoline on Calcium Channel Currents and Caffeine-induced Calcium Release in Isolated Single Ventricular Myocyte of Guinea Pig

    Institute of Scientific and Technical Information of China (English)

    林先明; 李真; 胡本容; 夏国瑾; 姚伟星; 向继洲

    2002-01-01

    Summary: The effects of Arecoline (Are) on calcium mobilization were investigated. In isolatedsingle ventricular myocyte of guinea pig, patch clamp whole cell recording techniques were used torecord the current of L-type calcium channel and cytosolic Ca2+ level ([Ca2+]i) labeled with fluo-rescence probe Fluo-3/AM was measured under a laser scanning confocal microscope. Results re-vealed that Are (3-100 μmol/L) could inhibit L-type calcium current in a concentration-depen-dent manner and the value of IC50 was 33. 73μmol/L (n= 5). In the absence of extracellular calci-um, the resting levels of [Ca2+]i was not affected by Are (n=6, P>0. 05), but pretreatmentwith Are (30 μmol/L) could significantly inhibit the [Ca2+]i elevation induced by caffeine (10mmol/L, n = 6, P < 0. 01). It was concluded that Are could inhibit not only calcium influxthrough L-type calcium channel but also calcium release from sarcoplasmic reticulum.

  8. Amphetamine concentrations in human urine following single-dose administration of the calcium antagonist prenylamine-studies using fluorescence polarization immunoassay (FPIA) and GC-MS.

    Science.gov (United States)

    Kraemer, Thomas; Roditis, Susanne K; Peters, Frank T; Maurer, Hans H

    2003-03-01

    Prenylamine (R,S-N-(3,3-diphenylpropyl-methyl-2-phenethylamine), a World Health Organization class V calcium antagonist, is known to be metabolized to amphetamine. In this study, amphetamine concentrations after a single-dose administration of prenylamine were determined to check if they reached values that could be of analytical and/or pharmacological importance in clinical and forensic toxicology. Enantiomeric composition of amphetamine was also studied. Five volunteers received a single 120-mg oral dose of prenylamine. Urine samples were analyzed using the Abbott TDx immunoassay Amphetamine/Methamphetamine II and using our routine systematic toxicological analysis (STA) gas chromatography-mass spectrometry (GC-MS) procedure. For quantitation purposes, GC-MS was used in the selected-ion monitoring (SIM) mode (ions m/z 118, 122, 240, 244) after solid-phase extraction (Isolute Confirm HCX) and derivatization (heptafluorobutyric anhydride). Amphetamine-d5 was used as internal standard (IS). Chiral separation of the heptafluorobutyrated amphetamine enantiomers was achieved using an Astec Chiraldex G-PN column. The TDx results showed a great variability for the different volunteers. A urine sample of one volunteer showed results as high as 3200 ng/mL, whereas the urine samples of another volunteer never gave results greater than the TDx detection limit (100 ng/mL). Using the STA procedure, the presence of amphetamine could be confirmed in all urine samples with TDx results greater than the cutoff value (300 ng/mL). Using the GC-MS SIM method, amphetamine concentrations up to 1280 ng/mL were determined. Chiral analysis revealed that both enantiomers of amphetamine were present in the samples with a surplus of the S(+)-enantiomer in the early phase of excretion. Forensic implications are discussed.

  9. Milk production, peripartal liver triglyceride concentration and plasma metabolites of dairy cows fed diets supplemented with calcium soaps or hydrogenated triglycerides of palm oil.

    Science.gov (United States)

    Karcagi, Roland G; Gaál, Tibor; Ribiczey, Piroska; Huszenicza, Gyula; Husvéth, Ferenc

    2010-05-01

    The aim of the study was to test the effect of rumen-inert fat supplements of different chemical forms or containing different unsaturated/saturated (U/S) fatty acid contents on milk production, milk composition and liver and blood metabolic variables of high-yielding dairy cows in the peripartal period. Thirty Holstein-Friesian dairy cows were divided into three equal groups and fed a corn silage-based diet, without fat supplementation (control) or supplemented with 11.75 MJ NEl per day of calcium soaps of palm oil fatty acids (CAS; U/S=61/39) or with 11.75 MJ NEl per day of hydrogenated palm oil triglyceride (HTG; U/S=6/94). Each diet was fed from 25+/-2 d prior to the expected calving to 100+/-5 d post partum. Compared with the control, both CAS and HTG supplementation resulted in an increase of the average milk yield. Milk fat content and fat-corrected milk yield were higher in the HTG group but lower in the CAS group than in the control group. In all groups liver triglyceride concentrations (TGL) increased from 15 d prepartum to 5 d post partum, and then decreased thereafter. At 5 d TGL was lower in the HTG group than control or CAS cows. No significant differences were detected in TGL among dietary treatments at 15 d prepartum and 25 d post partum. Higher plasma glucose and insulin and lower non-esterified fatty acids and beta-hydroxybutyrate concentrations and aspartate aminotransferase activity were measured in the HTG group than in the control or CAS groups at 5 d or 25 d post partum. Our results show that HTG may provide a better energy supply for high-yielding dairy cows in negative energy balance than CAS around calving.

  10. Examination of tapered plastic multimode fiber-based sensor performance with silver coating for different concentrations of calcium hypochlorite by soft computing methodologies--a comparative study.

    Science.gov (United States)

    Zakaria, Rozalina; Sheng, Ong Yong; Wern, Kam; Shamshirband, Shahaboddin; Wahab, Ainuddin Wahid Abdul; Petković, Dalibor; Saboohi, Hadi

    2014-05-01

    A soft methodology study has been applied on tapered plastic multimode sensors. This study basically used tapered plastic multimode fiber [polymethyl methacrylate (PMMA)] optics as a sensor. The tapered PMMA fiber was fabricated using an etching method involving deionized water and acetone to achieve a waist diameter and length of 0.45 and 10 mm, respectively. In addition, a tapered PMMA probe, which was coated by silver film, was fabricated and demonstrated using a calcium hypochlorite (G70) solution. The working mechanism of such a device is based on the observation increment in the transmission of the sensor that is immersed in solutions at high concentrations. As the concentration was varied from 0 to 6 ppm, the output voltage of the sensor increased linearly. The silver film coating increased the sensitivity of the proposed sensor because of the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber. In this study, the polynomial and radial basis function (RBF) were applied as the kernel function of the support vector regression (SVR) to estimate and predict the output voltage response of the sensors with and without silver film according to experimental tests. Instead of minimizing the observed training error, SVR_poly and SVR_rbf were used in an attempt to minimize the generalization error bound so as to achieve generalized performance. An adaptive neuro-fuzzy interference system (ANFIS) approach was also investigated for comparison. The experimental results showed that improvements in the predictive accuracy and capacity for generalization can be achieved by the SVR_poly approach in comparison to the SVR_rbf methodology. The same testing errors were found for the SVR_poly approach and the ANFIS approach.

  11. Transport of calcium in seedlings and cuttings of mung bean

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, W.

    1984-01-01

    At germination, a very small proportion of stored calcium is mobilized to the axis in the absence of exogenous supplies of calcium. There is no evidence for transport in phloem since exported calcium does not enter the seedling root. /sup 45/Calcium is not redistributed when applied to cotyledons at germination of leaves of seedlings. A subsequent large addition of unlabelled calcium promotes a small redistribution from leaves. Triiodobenzoic acid (TIBA), applied to leaves, leads to a small reduction in calcium accumulation but does not effect redistribution. Auxin is without effect and auxin plus TIBA promotes accumulation. These results are discussed in relation to possible extracellular binding sites for calcium.

  12. The Effect of Calcitonin Gene-Related Peptide (CGRP on the Cytosolic Calcium Concentration and Force in Rat Intramural Coronary Arteries

    Directory of Open Access Journals (Sweden)

    M. Sheykhzade

    2001-01-01

    Full Text Available The aim of this study was to investigate the mechanism of CGRP-induced relaxation in intramural rat coronary arteries. By using FURA-2 technique, cytosolic Ca2+-concentration ([Ca2+]i was measured during contraction of the vascular smooth muscle with receptor-dependent agonist (tromboxane A2 analogue U46619 and with high concentration of extracellular potassium. At a steady state of contraction, the increase in [Ca2+]i induced by 300 nM U46619 (100״x 14 nM, n = 7 was similar to that induced by 36 mM K+ (98 ״x 9 nM, n = 7. However, the active tension induced by 300 nM U46619 was significantly (p < 0.01 higher than that induced by 36 mM K+. CGRP concentration-dependently (10 pM - 10 nM reduced both the [Ca2+]i and tension of coronary arteries precontracted with either U46619 or BAY K 8644, and also of resting coronary arteries in PSS. In 36 mM K+-depolarized arteries, CGRP reduced only the tension without affecting the [Ca2+]i. In 300 nM U46619 precontracted arteries, pretreatment with 10 μM thapsigargin significantly (p < 0.05 attenuated the CGRP-induced reduction in the tension (but not [Ca2+]i. In 300 nM U46619 precontracted arteries, pretreatment with either 100 nM charybdotoxin or 100 nM iberiotoxin or 10 nM felodipine significantly (p < 0.05 attenuated the CGRP-induced reduction in both [Ca2+]i and the tension. In contrast, 1 μM glibenclamide did not affect the CGRP-induced responses in these coronary arteries. In resting coronary arteries, only pretreatment with the combination of 1 μM glibenclamide and 100 nM charybdotoxin attenuated the CGRP-induced decrease in the [Ca2+]i and tension, suggesting a different mechanism of action for CGRP in resting coronary arteries. We conclude that CGRP relaxes precontracted rat coronary arteries via three mechanisms: (1 a decrease in [Ca2+]i by inhibiting the Ca2+ influx through membrane hyperpolarization mediated partly by activation of BKCa channels, (2 a decrease in [Ca2+]i presumably by

  13. The calcium mobilizing tumor promoting agent, thapsigargin elevates the platelet cytoplasmic free calcium concentration to a higher steady state level. A possible mechanism of action for the tumor promotion

    DEFF Research Database (Denmark)

    Thastrup, Ole; Foder, B; Scharff, O

    1987-01-01

    The ability of the platelet agonists thapsigargin (Tg) and thrombin to elevate the cytoplasmic free calcium level ([Ca2+]i) was examined. Both agonists induced a transient increase of [Ca2+]i with a different time-course, however. Thus, the maximal [Ca2+]i was reached 15 sec and 2 min after...... stimulation with thrombin and Tg, respectively. The thrombin induced rise of [Ca2+]i was reversible, which indicates that active calcium sequestration and/or extrusion is operating. Tg affected [Ca2+]i in a divergent manner, thus, [Ca2+]i was stabilized on a elevated level without initial formation...... of a pronounced peak. The decline in [Ca2+]i observed after thrombin stimulation was not impaired by the calmodulin binding drug trifluoperazine but it was strongly reduced by vanadate, which suggests the active calcium transport systems to be insensitive to calmodulin. We put forward the hypothesis...

  14. 大鼠吸烟模型中精子活力和钙离子浓度的变化%The Variation of the Sperms Activity and Calcium Ion Concentration in Rats with Smoking

    Institute of Scientific and Technical Information of China (English)

    孙晓科; 周桂香; 郑圣霞; 姚丽娟

    2016-01-01

    Objective To explore the relationship between calcium concentration and sperm activity.Methods Calcium imaging system was used to observe the calcium signal of sperm in the experimental group and control mice. Results The results showed that the concentration of calcium in the sperms of rats decreased because of smoking, leading to a reduced sperm motility.Conclusion Somking has a detrimental affect on sperm activity and may lead to a harmful reproductive injury.%目的:研究香烟烟雾对大鼠精子活力的影响,分析钙离子浓度与精子活力变化的相关性。方法采用吸烟大鼠模型的成熟精子为研究对象,通过钙成像系统观察对照组和实验组精子钙信号变化,同时利用伊红染色法检测精子存活率的变化。结果吸烟会导致钙离子浓度降低,同时导致精子存活率的降低。结论该实验在分子水平证明吸烟对精液质量有危害性,为吸烟有害生殖健康提供了有力依据。

  15. Calcium signalling and calcium channels: evolution and general principles.

    Science.gov (United States)

    Verkhratsky, Alexei; Parpura, Vladimir

    2014-09-15

    Calcium as a divalent cation was selected early in evolution as a signaling molecule to be used by both prokaryotes and eukaryotes. Its low cytosolic concentration likely reflects the initial concentration of this ion in the primordial soup/ocean as unicellular organisms were formed. As the concentration of calcium in the ocean subsequently increased, so did the diversity of homeostatic molecules handling calcium. This includes the plasma membrane channels that allowed the calcium entry, as well as extrusion mechanisms, i.e., exchangers and pumps. Further diversification occurred with the evolution of intracellular organelles, in particular the endoplasmic reticulum and mitochondria, which also contain channels, exchanger(s) and pumps to handle the homeostasis of calcium ions. Calcium signalling system, based around coordinated interactions of the above molecular entities, can be activated by the opening of voltage-gated channels, neurotransmitters, second messengers and/or mechanical stimulation, and as such is all-pervading pathway in physiology and pathophysiology of organisms.

  16. Structure-specific effects of lipidated oxytocin analogs on intracellular calcium levels, parental behavior, and oxytocin concentrations in the plasma and cerebrospinal fluid in mice.

    Science.gov (United States)

    Cherepanov, Stanislav M; Yokoyama, Shigeru; Mizuno, Akira; Ichinose, Wataru; Lopatina, Olga; Shabalova, Anna A; Salmina, Alla B; Yamamoto, Yasuhiko; Okamoto, Hiroshi; Shuto, Satoshi; Higashida, Haruhiro

    2017-02-01

    Oxytocin (OT) is a neuroendocrine nonapeptide that plays an important role in social memory and behavior. Nasal administration of OT has been shown to improve trust in healthy humans and social interaction in autistic subjects in some clinical trials. As a central nervous system (CNS) drug, however, OT has two unfavorable characteristics: OT is short-acting and shows poor permeability across the blood-brain barrier, because it exists in charged form in the plasma and has short half-life. To overcome these drawbacks, an analog with long-lasting effects is required. We previously synthesized the analog, lipo-oxytocin-1 (LOT-1), in which two palmitoyl groups are conjugated to the cysteine and tyrosine residues. In this study, we synthesized and evaluated the analogs lipo-oxytocin-2 (LOT-2) and lipo-oxytocin-3 (LOT-3), which feature the conjugation of one palmitoyl group at the cysteine and tyrosine residues, respectively. In human embryonic kidney-293 cells overexpressing human OT receptors, these three LOTs demonstrated comparably weak effects on the elevation of intracellular free calcium concentrations after OT receptor activation, compared to the effects of OT. The three LOTs and OT exhibited different time-dependent effects on recovery from impaired pup retrieval behavior in sires of CD38-knockout mice. Sires treated with LOT-1 showed the strongest effect, whereas others had no or little effects at 24 h after injection. These results indicated that LOTs have structure-specific agonistic effects, and suggest that lipidation of OT might have therapeutic benefits for social impairment.

  17. The critical role of lipid rafts nanodomains in the cross-talk between calcium and reactive oxygen and nitrogen species in cerebellar granule neurons apoptosis by extracellular potassium deprivation

    Directory of Open Access Journals (Sweden)

    Carlos Gutierrez-Merino

    2016-01-01

    Full Text Available The apoptosis of cerebellar granule neurons (CGN induced by low-potassium in serum free medium in vitro has become a widely used model for neuronal apoptosis during in vivo brain development. In this review we shall summarize first the basic features of this model for neuronal apoptosis. Next, we shall focus on the L-type calcium channels (LTCC inactivation as the primary pro-apoptotic signal in low K+-induced CGN death. This apoptotic process can be split into two major and sequential cellular signaling phases: one reversible phase that offers a temporal window for therapeutic interventions to prevent neuronal death, and an irreversible later phase. Therefore, we shall comment next the critical role of reactive oxygen species (ROS production and major ROS sources triggering the entry of CGN in the irreversible stages of low K+-induced apoptosis. Then, we shall present the experimental evidences showing clustering of LTCC and ROS producing enzymes in plasma membrane lipid rafts of CGN matured in vitro, which have opened new perspectives for cell signaling in the early and reversible phase of this apoptosis. The role of lipid rafts nanodomains as fast response calcium/nitric oxide transducers of the switch of CGN to low K+ medium will be discussed next. The two major conclusions drawn from this review are: (1 deregulation of the pool of cytochrome b5 reductase associated to plasma membrane-lipid rafts, at least in part due to overexpression of cytochrome b5, can account for the critical superoxide anion overshot which triggers the entry in the irreversible phase of low K+ apoptosis of CGN, and (2 LTCC inactivation is rapidly transduced by lipid rafts nanodomains into a large drop of cytosolic calcium, a switch-off of nitric oxide production and subsequent inactivation of survival signaling pathways dependent on the activity of CaMKII, PKA and Akt/PKB kinases.

  18. Activation of the calcium sensing receptor with cinacalcet increases serum gastrin levels in healthy older subjects

    Science.gov (United States)

    Gastric acidity is postulated to enhance calcium absorption since calcium is better dissolved at low pH. Extracellular calcium stimulates gastrin and gastric acid secretion in humans. Ex vivo studies indicate that the calcium sensing receptor (CaR), which is expressed on the surface of human G cells...

  19. Extracellular DNA metabolism in Haloferax volcanii

    Directory of Open Access Journals (Sweden)

    Scott eChimileski

    2014-02-01

    Full Text Available Extracellular DNA is found in all environments and is a dynamic component of the micro-bial ecosystem. Microbial cells produce and interact with extracellular DNA through many endogenous mechanisms. Extracellular DNA is processed and internalized for use as genetic information and as a major source of macronutrients, and plays several key roles within prokaryotic biofilms. Hypersaline sites contain some of the highest extracellular DNA con-centrations measured in nature–a potential rich source of carbon, nitrogen and phosphorus for halophilic microorganisms. We conducted DNA growth studies for the halophilic archaeon Haloferax volcanii DS2 and show that this model Halobacteriales strain is capable of using exogenous double-stranded DNA as a nutrient. Further experiments with varying medium composition, DNA concentration and DNA types revealed that DNA is utilized primarily as a phosphorus source, that growth on DNA is concentration-dependent and that DNA isolated from different sources is metabolized selectively, with a bias against highly divergent methylated DNA sources. Additionally, fluorescence microscopy experiments showed that labeled DNA colocalized with Haloferax volcanii cells. The gene Hvo_1477 was also identified using a comparative genomic approach as a factor likely to be involved in extracellular DNA processing at the cell surface, and deletion of Hvo_1477 created an H. volcanii strain deficient in its ability to grow on extracellular DNA. Widespread distribution of Hvo_1477 homologs in archaea suggests metabolism of extracellular DNA may be of broad ecological and physiological relevance in this domain of life.

  20. Store-operated calcium signaling in neutrophils.

    Science.gov (United States)

    Clemens, Regina A; Lowell, Clifford A

    2015-10-01

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

  1. Calcium-sensing receptor in breast physiology and cancer

    OpenAIRE

    Wonnam Kim; Wysolmerski, John J.

    2016-01-01

    The calcium-sensing receptor (CaSR) is expressed in normal breast epithelial cells and in breast cancer cells. During lactation, activation of the CaSR in mammary epithelial cells increases calcium transport into milk and inhibits parathyroid hormone-related protein (PTHrP) secretion into milk and into the circulation. The ability to sense changes in extracellular calcium allows the lactating breast to actively participate in the regulation of systemic calcium and bone metabolism, and to coor...

  2. Finding of Optimal Calcium Ion Probes for Fluorescence Lifetime Measurement

    Science.gov (United States)

    Yoshiki, Keisuke; Azuma, Hiroki; Yoshioka, Kazuhiko; Hashimoto, Mamoru; Araki, Tsutomu

    We have investigated the fluorescence lifetime properties of 8 calcium ion probes, calcium-green-1, calcium green-2, calcium green-5N, calcium orange, oregon green 488 BAPTA-6F, fluo-3, fluo-4, and fluo-5N. We found that the decay time of calcium green-5N varied more sensitively with calcium concentration than calcium green-1 which was known to be a highly sensitive probe. We have also found that the center of observable range of calcium concentration by fluorescence lifetime measurement is lower than that by fluorescence intensity measurement.

  3. Abnormalities of serum calcium and magnesium

    Science.gov (United States)

    Neonatal hypocalcemia is defined as a total serum calcium concentration of <7 mg/dL or an ionized calcium concentration of <4 mg/dL (1mmol/L). In very low birth weight (VLBW) infants, ionized calcium values of 0.8 to 1 mmol/L are common and not usually associated with clinical symptoms. In larger in...

  4. Stage-specific changes in calcium concentration in crustacean (Callinectes sapidus) Y-organs during a natural molting cycle, and their relation to the hemolymphatic ecdysteroid titer.

    Science.gov (United States)

    Chen, Hsiang-Yin; Dillaman, Richard M; Roer, Robert D; Watson, R Douglas

    2012-09-01

    Secretion of ecdysteroid molting hormones by crustacean Y-organs is suppressed by molt-inhibiting hormone (MIH). The suppressive effect of MIH on ecdysteroidogenesis is mediated by one or more cyclic nucleotide second messengers. In addition, existing data indicate that ecdysteroidogenesis is positively regulated (stimulated) by intracellular Ca(++). Despite the apparent critical role of calcium in regulating ecdysteroidogenesis, the level of Ca(++) in Y-organ cells has not been previously measured during a natural molting cycle for any crustacean species. In studies reported here, a fluorescent calcium indicator (Fluo-4) was used to measure Ca(++) levels in Y-organs during a molting cycle of the blue crab, Callinectes sapidus. Mean calcium fluorescence increased 5.8-fold between intermolt (C4) and stage D3 of premolt, and then dropped abruptly, reaching a level in postmolt (A) that was not significantly different from that in intermolt (P>0.05). The level of ecdysteroids in hemolymph of Y-organ donor crabs (measured by radioimmunoassay) showed an overall pattern similar to that observed for calcium fluorescence, rising from 2.9 ng/mL in intermolt to 357.1 ng/mL in D3 (P<0.05), and then dropping to 55.3 ng/mL in D4 (P<0.05). The combined results are consistent with the hypothesis that ecdysteroidogenesis is stimulated by an increase in intracellular Ca(++). Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Effects of calcium salts of long-chain fatty acids and rumen-protected methionine on plasma concentrations of ghrelin, glucagon-like peptide-1 (7 to 36) amide and pancreatic hormones in lactating cows.

    Science.gov (United States)

    Fukumori, R; Sugino, T; Shingu, H; Moriya, N; Hasegawa, Y; Kojima, M; Kangawa, K; Obitsu, T; Kushibiki, S; Taniguchi, K

    2012-02-01

    Our objective was to determine the effects of calcium salts of long-chain fatty acids (CLFAs) and rumen-protected methionine (RPM) on plasma concentrations of ghrelin, glucagon-like peptide-1 (7 to 36) amide, and pancreatic hormones in lactating cows. Four Holstein cows in midlactation were used in a 4 by 4 Latin square experiment in each 2-wk period. Cows were fed corn silage-based diets with supplements of CLFAs (1.5% added on dry matter basis), RPM (20 g/d), CLFAs plus RPM, and without supplement. Jugular blood samples were taken from 1 h before to 2 h after morning feeding at 10-min intervals on day 12 of each period. CLFAs decreased dry matter intake, but RPM did not affect dry matter intake. Both supplements of CLFAs and RPM did not affect metabolizable energy intake and milk yield and composition. Plasma concentrations of NEFAs, triglyceride (TG), and total cholesterol (T-Cho) were increased with CLFAs alone, but increases of plasma concentrations of TG and T-Cho were moderated by CLFAs plus RPM. Calcium salts of long-chain fatty acids increased plasma ghrelin concentration, and the ghrelin concentration with CLFAs plus RPM was the highest among the treatments. Plasma concentrations of glucagon-like peptide-1, glucagon, and insulin were decreased with CLFAs, whereas adding RPM moderated the decrease of plasma glucagon concentration by CLFAs. These results indicate that the addition of methionine to cows given CLFAs increases plasma concentrations of ghrelin and glucagon associated with the decrease in plasma concentrations of TG and T-Cho.

  6. 白藜芦醇降低大鼠心室肌细胞内游离钙浓度%Resveratrol reduces intracellular free calcium concentration in rat ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    刘政; 张利萍; 马会杰; 王川; 李明; 王庆山

    2005-01-01

    Resveratrol (trans-3,4',5-trihydroxy stilbene), a phytoalexin found in grape skins and red wine, has been reported to have a wide range of biological and pharmacological properties. It has been speculated that resveratrol may have cardioprotective activity.The objective of our study was to investigate the effects of resveratrol on intracellular calcium concentratoin ([Ca2+]i) in rat ventricular myocytes. [Ca2+]i was detected by laser scanning confocal microscopy. The results showed that resveratrol (15~60 μmol/L) reduced [Ca2+]i in normal and Ca2+-free Tyrode's solution in a concentration-dependent manner. The effects of resveratrol on [Ca2+]i in normal Tyrode's solution was partially inhibited by pretreatment with sodium orthovanadate (Na3VO4, 1.0 mmol/L, P<0.01), an inhibitor of protein tyrosine phosphatase, or L-type Ca2+ channel agonist Bay K8644 (10 μmol/L, P<0.05), but could not be antagonized by NO synthase inhibitor L-NAME (1.0 mmol/L). Resveratrol also markedly inhibited the ryanodine-induced [Ca2+]i increase in Ca2+-free Tyrode's solution (P<0.01). When Ca2+ waves were produced by increasing extracellular Ca2+ concentration from 1 to 10 mmol/L,resveratrol (60 μmol/L) could reduce the velocity and duration of propagating waves, and block the propagating waves of elevated [Ca2+]i. These results suggest that resveratrol may reduce the [Ca2+]i in isolated rat ventricular myocytes. The inhibition of voltagedependent Ca2+ channel and tyrosine kinase, and alleviation of Ca2+ release from sarcoplasmic reticulum (SR) are possibly involved in the effects of resveratrol on rat ventricular myocytes. These findings could help explain the protective activity of resveratrol against cardiovascular disease.%实验旨在研究白藜芦醇(resveratrol)对大鼠心室肌细胞内钙浓度(intracellular calcium concentratoin,[Ca2+]i)的影响.应用激光共聚焦显微镜技术记录心室肌细胞内的钙荧光强度.结果表明:在正常台氏液和

  7. Cross-talk between signaling pathways can generate robust oscillations in calcium and cAMP.

    Directory of Open Access Journals (Sweden)

    Fernando Siso-Nadal

    Full Text Available BACKGROUND: To control and manipulate cellular signaling, we need to understand cellular strategies for information transfer, integration, and decision-making. A key feature of signal transduction is the generation of only a few intracellular messengers by many extracellular stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Here we model molecular cross-talk between two classic second messengers, cyclic AMP (cAMP and calcium, and show that the dynamical complexity of the response of both messengers increases substantially through their interaction. In our model of a non-excitable cell, both cAMP and calcium concentrations can oscillate. If mutually inhibitory, cross-talk between the two second messengers can increase the range of agonist concentrations for which oscillations occur. If mutually activating, cross-talk decreases the oscillation range, but can generate 'bursting' oscillations of calcium and may enable better filtering of noise. CONCLUSION: We postulate that this increased dynamical complexity allows the cell to encode more information, particularly if both second messengers encode signals. In their native environments, it is unlikely that cells are exposed to one stimulus at a time, and cross-talk may help generate sufficiently complex responses to allow the cell to discriminate between different combinations and concentrations of extracellular agonists.

  8. 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.

  9. Two chromogranin a-derived peptides induce calcium entry in human neutrophils by calmodulin-regulated calcium independent phospholipase A2.

    Directory of Open Access Journals (Sweden)

    Dan Zhang

    Full Text Available BACKGROUND: Antimicrobial peptides derived from the natural processing of chromogranin A (CgA are co-secreted with catecholamines upon stimulation of chromaffin cells. Since PMNs play a central role in innate immunity, we examine responses by PMNs following stimulation by two antimicrobial CgA-derived peptides. METHODOLOGY/PRINCIPAL FINDINGS: PMNs were treated with different concentrations of CgA-derived peptides in presence of several drugs. Calcium mobilization was observed by using flow cytometry and calcium imaging experiments. Immunocytochemistry and confocal microscopy have shown the intracellular localization of the peptides. The calmodulin-binding and iPLA2 activating properties of the peptides were shown by Surface Plasmon Resonance and iPLA2 activity assays. Finally, a proteomic analysis of the material released after PMNs treatment with CgA-derived peptides was performed by using HPLC and Nano-LC MS-MS. By using flow cytometry we first observed that after 15 s, in presence of extracellular calcium, Chromofungin (CHR or Catestatin (CAT induce a concentration-dependent transient increase of intracellular calcium. In contrast, in absence of extra cellular calcium the peptides are unable to induce calcium depletion from the stores after 10 minutes exposure. Treatment with 2-APB (2-aminoethoxydiphenyl borate, a store operated channels (SOCs blocker, inhibits completely the calcium entry, as shown by calcium imaging. We also showed that they activate iPLA2 as the two CaM-binding factors (W7 and CMZ and that the two sequences can be aligned with the two CaM-binding domains reported for iPLA2. We finally analyzed by HPLC and Nano-LC MS-MS the material released by PMNs following stimulation by CHR and CAT. We characterized several factors important for inflammation and innate immunity. CONCLUSIONS/SIGNIFICANCE: For the first time, we demonstrate that CHR and CAT, penetrate into PMNs, inducing extracellular calcium entry by a CaM-regulated i

  10. 幼儿牙龈粘膜细胞钙离子浓度与患龋状况关系的研究%Analysis of relationship between gingival cell calcium ions concentration and caries status in children

    Institute of Scientific and Technical Information of China (English)

    刘芸; 石四箴

    2012-01-01

    Objective To measure the intramllnlar calcium ions cunuentration of gmgival cells and to discuss the relationship between the calcium ions concentration and caries status in children. Methods Fifty children aged 3-5 year-old were divided into caries free group and high caries-susceptibility group according to caries status. The lahial gingival deciduous cells in anterior mandibular zone were collected and died, and then the fluorescent intensity of calcium ions was measured by Laser Scanning Contocst Microscopy And the relationship between the fluorescent intensity and caries status was statistically analyzed. Results The fluorescent intensity of gingival cell calcium ions in high caries-susceptibility group was statistically lower than that of caries free group. No statistical difference of calcium ions florescent intensities was found among different genders, different ages. The florescent intensity of gingival cell calcium ions was negatively correlated with dft and CS1. Conclusion The calcium ions concentration of gingival cells is related with caries status to some extent in 3~5 aged children. The more serious the caries status is, the lower the calcium ions concentration is.%目的 测定幼儿牙龈粘膜细胞内钙离子浓度;探讨幼儿牙龈粘膜细胞内钙离子浓度与患龋状况的关系.方法 将50名3~5岁幼儿按患龋状况分为无龋组和龋病高危组.采集幼儿下前矛区唇侧牙龈粘膜脱落细胞,经染色后用激光扫描共聚焦显微镜测定细胞内钙离子的荧光强度,统计分析其与龋患程度的关系.结果 高危组幼儿牙龈粘膜细胞的钙离子荧光强度低于无龋组,两组间差异有高度统计学意义;不同性别,不同年龄间牙龈粘膜细胞的钙离子荧光强度无统计学差异;牙龈粘膜细胞钙离子荧光强度值与dft、CSI间分别呈等级负相关关系.结论 3~5岁幼儿牙龈粘膜细胞钙离子浓度与龋患程度有一定相关性,龋患程度重则钙离子浓度低.

  11. Calcium in diet

    Science.gov (United States)

    ... D is needed to help your body use calcium. Milk is fortified with vitamin D for this reason. ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ...

  12. 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

  13. Extracellular calmodulin: A polypeptide signal in plants?

    Institute of Scientific and Technical Information of China (English)

    孙大业; 唐文强; 马力耕

    2001-01-01

    Traditionally, calmodulin (CaM) was thought to be a multi-functional receptor for intracellular Ca2+ signals. But in the last ten years, it was found that CaM also exists and acts extracellularly in animal and plant cells to regulate many important physiological functions. Laboratory studies by the authors showed that extracellular CaM in plant cells can stimulate the proliferation of suspension cultured cell and protoplast; regulate pollen germination and pollen tube elongation,and stimulate the light-independent gene expression of Rubisco small subunit (rbcS). Furthermore,we defined the trans-membrane and intracellular signal transduction pathways for extracellular CaM by using a pollen system. The components in this pathway include heterotrimeric G-protein,phospholipase C, IP3, calcium signal and protein phosphorylation etc. Based on our findings, we suggest that extracellular CaM is a polypeptide signal in plants. This idea strongly argues against the traditional concept that there is no intercellular polypeptide signal in plants.

  14. Dual pathways of calcium entry in spike and plateau phases of luteinizing hormone release from chicken pituitary cells: sequential activation of receptor-operated and voltage-sensitive calcium channels by gonadotropin-releasing hormone

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.S.; Wakefield, I.K.; King, J.A.; Mulligan, G.P.; Millar, R.P.

    1988-04-01

    It has previously been shown that, in pituitary gonadotrope cells, the initial rise in cytosolic Ca2+ induced by GnRH is due to a Ca2+ mobilization from intracellular stores. This raises the possibility that the initial transient spike phase of LH release might be fully or partially independent of extracellular Ca2+. We have therefore characterized the extracellular Ca2+ requirements, and the sensitivity to Ca2+ channel blockers, of the spike and plateau phases of secretion separately. In the absence of extracellular Ca2+ the spike and plateau phases were inhibited by 65 +/- 4% and 106 +/- 3%, respectively. Both phases exhibited a similar dependence on concentration of extracellular Ca2+. However, voltage-sensitive Ca2+ channel blockers D600 and nifedipine had a negligible effect on the spike phase, while inhibiting the plateau phase by approximately 50%. In contrast, ruthenium red, Gd3+ ions, and Co2+ ions inhibited both spike and plateau phases to a similar extent as removal of extracellular Ca2+. A fraction (35 +/- 4%) of spike phase release was resistant to removal of extracellular Ca2+. This fraction was abolished after calcium depletion of the cells by preincubation with EGTA in the presence of calcium ionophore A23187, indicating that it depends on intracellular Ca2+ stores. Neither absence of extracellular Ca2+, nor the presence of ruthenium red or Gd3+ prevented mobilization of 45Ca2+ from intracellular stores by GnRH. We conclude that mobilization of intracellular stored Ca2+ is insufficient by itself to account for full spike phase LH release.

  15. Macronutrientes em folhas diagnósticas do capim-tanzânia adubado com nitrogênio e cálcio Macronutrients concentrations in Tanzania guineagrass diagnostic leaves supplied with nitrogen and calcium rates

    Directory of Open Access Journals (Sweden)

    Cristiane Prezotto Silveira

    2010-04-01

    .50; 1.75; 3.00; 4.25 e 5.50 mmol L-1 resulting in 13 nitrogen:calcium combinations (mmol L-1: 2:0.50; 2:3.00; 2:5.50; 9:1.75; 9:4.25; 16:0.50; 16:3.00; 16:5.50; 23:1.75; 23:4.25; 30:0.50; 30:3.00 and 30:5.50. Macronutrient concentrations were determined in the two recently expanded leaf blades (diagnostic leaves collected in the three harvests of Tanzania guineagrass. The results showed that, in the first harvest of the plants, calcium rates did not interact with nitrogen for any of the nutritional traits, except for sulphur concentration in the diagnostic leaves. The interaction nitrogen × calcium was significant for concentrations of calcium and sulphur in the diagnostic leaves at the second and third samplings of the grass. Nitrogen rates and, not calcium rates, are determinant for nitrogen, phosphorus, and potassium concentrations in the diagnostic leaves of Tanzania guineagrass. The concentration of calcium at the first harvest of the grass depends only on the supply of this nutrient. Concentration of magnesium in plant tissue decreases as nitrogen or calcium supply increases. Reduction of calcium to 40% of that one used in the nutrient solution does not reduce nutritional parameters of this grass, even with the supply of high nitrogen rate.

  16. Binding and release of brain calcium by low-level electromagnetic fields: A review

    Science.gov (United States)

    Adey, W. R.; Bawin, S. M.

    Evidence has accumulated that sensitivity of brain tissue to specific weak oscillating electromagnetic fields occurs in the absence of significant tissue heating (less than 0.1°C). This review focuses on the ‘windowed’ character of sensitivities of calcium binding and electrical activity in brain tissue to low-frequency modulation and intensity characteristics of impressed RF fields. ELF fields decrease calcium efflux from isolated chick and cat cerebral tissue by about 15% only in narrow amplitude and frequency ‘windows,’ between 6 and 20 Hz and between 10 and 100 V/m (approximate tissue gradient, 10-7 V/cm). VHF (147 MHz) and UHF (450 MHz) fields increase calcium efflux from isolated chick brain by about 15% when amplitude modulated between 6 and 20 Hz, but only for incident fields in the vicinity of 1.0 mW/cm2. We have now shown that this increased efflux in response to 16-Hz amplitude-modulated 450-MHz, 0.75-mW/cm2 field exposure is insensitive to variations in calcium concentration from 0 to 4.16 mM in the testing solution but is enhanced by addition of hydrogen ions (0.108 mM 0.1 N HCl) and inhibited in the absence of normal bicarbonate ion levels (2.4 mM). In the presence of lanthanum ions (2.0 mM), which block transmembrane movement of calcium, exposure to these EM fields decreases the 45Ca2 + efflux. Low-frequency gradients may be transduced in a specific class of extracellular binding sites, normally occupied by calcium ions and susceptible to competitive hydrogen ion binding. Transductive coupling may involve coherent charge states between anionic sites on membrane surface glycoproteins, with longrange cooperative interactions triggered by weak extracellular electric fields. Proton ‘tunneling’ may occur at boundaries between coherent and noncoherent charge zones.

  17. 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.

  18. Calcium effect on the metabolic pathway of phosphorus accumulating organisms in enhanced biological phosphorus removal systems.

    Science.gov (United States)

    Zhang, Hai-Ling; Sheng, Guo-Ping; Fang, Wei; Wang, Yong-Peng; Fang, Cai-Yun; Shao, Li-Min; Yu, Han-Qing

    2015-11-01

    Phosphorus accumulating organisms (PAOs) have been found to act as glycogen-accumulating organisms (GAOs) under certain conditions, thus, the deterioration in the performance of enhanced biological phosphorus removal systems is not always attributed to the proliferation of GAOs. In this work, the effects of calcium on the metabolic pathway of PAOs were explored. It was found that when the influent Ca(2+) concentration was elevated, the tendency and extent of extracellular calcium phosphate precipitation increased, and the intracellular inert Ca-bound polyphosphate was synthesized, while the microbial population remained almost unchanged. The changes in the ratios of phosphorus released/acetate uptaken, the glycogen degraded/acetate uptaken and the poly-β-hydroxyalkanoates synthesized/acetate uptaken during the anaerobic period confirm that, as the influent Ca(2+) concentration was increased, the polyphosphate-accumulating metabolism was partially shifted to the glycogen-accumulating metabolism. At an influent Ca(2+) around 50 mg/L, in addition to the extracellular calcium phosphate precipitation, the intracellular inert Ca-bound polyphosphate synthesis might also be involved in the metabolic change of PAOs. The results of the present work would be beneficial to better understand the biochemical metabolism of PAOs in enhanced biological phosphorus removal systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Calcium supplements

    Science.gov (United States)

    ... Related Bone Diseases National Resource Center. Calcium and vitamin D: Important at every age. NIAMS.NIH.gov website. www.niams.nih.gov/Health_Info/Bone/Bone_Health/Nutrition . Updated May 2015. Accessed March ...

  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. Calcium Signaling Is Required for Erythroid Enucleation.

    Science.gov (United States)

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

    2016-01-01

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

  2. Calcium Signaling Is Required for Erythroid Enucleation.

    Directory of Open Access Journals (Sweden)

    Christina B Wölwer

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

  3. 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.

  4. Effects of Anthopleurin-Q on the Intracellular Free Ca2+ Concentration in Cultured Rat Cortical Astrocytes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To investigate the effect of anthopleurin-Q (AP-Q) on the intracellular Ca2+ concentration ([Ca2+ ]i) in cultured cortical astrocytes of rats. Methods: The [Ca2+ ]i was monitored by calcium imaging with Ca2+ sensitive fluorescent probe fura-2. Results: A concentration of 300 nmol/L AP-Q increased the [Ca2+ ]i in astrocytes by (136.98%±35.63%) (n=28),when compared with the baseline level. Furthermore, the elevation of [Ca2+]i was prevented by extracellular calcium free solution or when the extracellular Na+ was replaced by NMDG+ , and was decreased by Ni+ ,a non-specific antagonist of Na+/Ca2+ exchanger. Conclusion: AP-Q induced the intracellular [Ca2+ ]i elevation in cultured rat cortical astrocytes via activating the reverse mode of Na+/Ca2+ exchanger. AP-Q may be a useful tool to develop experimental model of seizures.

  5. [The Analysis for Probable Reasons of Cd4+ T-Cell Activation Non-Linear Dependence on Extra Cellular Calcium Ion Concentration in Human Peripheral Blood in vitro].

    Science.gov (United States)

    Litvinov, I S

    2015-01-01

    The analysis for probable reasons of CD4+ T-cell activation non-linear dependence on [Ca2+]o in HPB in vitro is the general aim of current work. At the beginning we pursued the analysis of receptor-dependent (the mixture of monoclonal antibodies (mAbs) to CD3 and CD28 molecules) and receptor-independent (phorbol-myristate-acetate and ionomycin mixture) means to activate T cells in vitro with different [Ca2+]o in HPB. The key role of intracellular T-cell signaling systems in activated T cells in their non-similar sensitivity to calcium ions in the blood was shown. The analysis of differentiation next stages of CD4+ T-cell activation in vitro relatively [Ca2+]o in PHB demonstrates the key role of the earliest induction stages in non-similar sensitivity to calcium ions in CD4+ T-cell activation in vitro. According to the pursued analysis; the non-similar sensitivity of CD4+ T-cell in vitro to activation is in no-way connected with pace differences on the primary stages of activation process. The comparison of CD4+ memory T cells with their naive T-cell precursors in the cell activation process in hypocalcemia conditions was made in the separate experimental series. The 1st maximum consists in average of 85% CD4+CD45R0high CD69+ memory T cells. Naive CD4+CD45RAlowCD69+ T cells constitute the remainder 15%. The 2nd maximum almost completely consists of CD4+CD45R0+CD69+ memory T cells. The ratio between CD4+CD69+ T cell maximums depends on donor ages and represents linear dependence with R = -0.981. The most probable candidate on the role of CD4+ T cell, being capable of activation in hypocalcemia conditions, are memory T lymphocytes, being resistant to ionomycin action (I R) subset. To check this assumption the mononuclear cells and their IR-fraction were prepared from donor PB. Then the mononuclear cells and their IR-fraction were activated by mAbs mixture at different [EGTA] values. For IR-fraction, enriched with CD4+CD45RA-CD45R0+ memory T cells, slightly seen 1st

  6. 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.

  7. Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

    OpenAIRE

    Silva, Raul F; Carmona, Jorge U; Rezende, Cleuza MF

    2012-01-01

    Background The clinical use of autologous platelet concentrates (also known as platelet-rich plasma) on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1) to describe and compare the cellular population in whole blood, lower fraction (A) and upper fraction (B) of platelet concentrates, 2) to measure and compare the transforming growth factor beta 1 (TGF-β1) concentration ...

  8. Hysteresis and calcium set-point for the calcium parathyroid hormone relationship in healthy horses.

    Science.gov (United States)

    Toribio, Ramiro E; Kohn, Catherine W; Sams, Richard A; Capen, Charles C; Rosol, Thomas J

    2003-02-15

    Abnormalities in calcium (Ca(2+)) homeostasis are reported in horses with several pathological conditions; however, there is little information on Ca(2+) regulation in horses. The objectives of the present study were to determine the Ca(2+) set-point in healthy horses, to determine whether the Ca(2+)/parathyroid hormone (PTH) response curves were characterized by hysteresis, and to determine if the order of experimentally induced hypocalcemia or hypercalcemia had an effect on PTH secretion. The Ca(2+) set-point and hysteresis were determined in 12 healthy horses by infusing Na(2)EDTA and calcium gluconate. The Ca(2+) set-point was 1.37 +/- 0.05 mmol/L, which is higher than values reported for humans and dogs (1.0-1.2 mmol/L). Hysteresis was present during hypocalcemia and hypercalcemia. Horses in which hypocalcemia was followed by hypercalcemia secreted more PTH (7440 +/- 740 pmol min/L) than horses in which hypercalcemia was followed by hypocalcemia (5990 +/- 570 pmol min/L). This study has demonstrated that the Ca(2+) set-point in the horse is higher than in other domestic animals and man. We have shown that the Ca(2+)/PTH relationship in horses is sigmoidal and displays hysteresis during both hypocalcemia and hypercalcemia, and that extracellular Ca(2+) concentrations may affect the response of the parathyroid gland to hypocalcemia.

  9. Extracellular Gd-CA

    DEFF Research Database (Denmark)

    Thomsen, Henrik S; Marckmann, Peter

    2008-01-01

    Until recently it was believed that extracellular gadolinium-based contrast agents were safe for both the kidneys and all other organs within the dose range up to 0.3 mmol/kg body weight. However, in 2006, it was demonstrated that some gadolinium-based contrast agents may trig the development of ...

  10. 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

  11. Role of low voltage activated calcium channels in neuritogenesis and active migration of embryonic neural progenitor cells.

    Science.gov (United States)

    Louhivuori, Lauri M; Louhivuori, Verna; Wigren, Henna-Kaisa; Hakala, Elina; Jansson, Linda C; Nordström, Tommy; Castrén, Maija L; Akerman, Karl E

    2013-04-15

    The central role of calcium influx and electrical activity in embryonic development raises important questions about the role and regulation of voltage-dependent calcium influx. Using cultured neural progenitor cell (NPC) preparations, we recorded barium currents through voltage-activated channels using the whole-cell configuration of the patch-clamp technique and monitored intracellular free calcium concentrations with Fura-2 digital imaging. We found that NPCs as well as expressing high-voltage-activated (HVA) calcium channels express functional low-threshold voltage-dependent calcium channels in the very early stages of differentiation (5 h to 1 day). The size of the currents recorded at -50 versus -20 mV after 1 day in differentiation was dependent on the nature of the charge carrier. Peak currents measured at -20 mV in the presence 10 mM Ca2+ instead of 10 mM Ba2+ had a tendency to be smaller, whereas the nature of the divalent species did not influence the amplitude measured at -50 mV. The T-type channel blockers mibefradil and NNC 55-0396 significantly reduced the calcium responses elicited by depolarizing with extracellular potassium, while the overall effect of the HVA calcium channel blockers was small at differentiation day 1. At differentiation day 20, the calcium responses were effectively blocked by nifedipine. Time-lapse imaging of differentiating neurospheres cultured in the presence of low-voltage-activated (LVA) blockers showed a significant decrease in the number of active migrating neuron-like cells and neurite extensions. Together, these data provide evidence that LVA calcium channels are involved in the physiology of differentiating and migrating NPCs.

  12. In vitro Determination of Extracellular Proteins from Xylella fastidiosa

    Science.gov (United States)

    Mendes, Juliano S.; Santiago, André S.; Toledo, Marcelo A. S.; Horta, Maria A. C.; de Souza, Alessandra A.; Tasic, Ljubica; de Souza, Anete P.

    2016-01-01

    The phytopathogen Xylella fastidiosa causes economic losses in important agricultural crops. Xylem vessel occlusion caused by biofilm formation is the major mechanism underlying the pathogenicity of distinct strains of X. fastidiosa. Here, we provide a detailed in vitro characterization of the extracellular proteins of X. fastidiosa. Based on the results, we performed a comparison with a strain J1a12, which cannot induce citrus variegated chlorosis symptoms when inoculated into citrus plants. We then extend this approach to analyze the extracellular proteins of X. fastidiosa in media supplemented with calcium. We verified increases in extracellular proteins concomitant with the days of growth and, consequently, biofilm development (3–30 days). Outer membrane vesicles carrying toxins were identified beginning at 10 days of growth in the 9a5c strain. In addition, a decrease in extracellular proteins in media supplemented with calcium was observed in both strains. Using mass spectrometry, 71 different proteins were identified during 30 days of X. fastidiosa biofilm development, including proteases, quorum-sensing proteins, biofilm formation proteins, hypothetical proteins, phage-related proteins, chaperones, toxins, antitoxins, and extracellular vesicle membrane components. PMID:28082960

  13. Experimental Research on Glauberite Dissolution in Calcium Liquid with Different Ion Concentration%不同离子浓度钙液环境中钙芒硝溶解试验研究

    Institute of Scientific and Technical Information of China (English)

    徐军; 梁卫国; 张继龙; 徐素国; 张传达

    2013-01-01

    为了提高岩盐伴生性钙芒硝矿进行资源化利用效率,对取自盐化制碱厂的淡钙液与钙芒硝矿进行了溶解反应试验,以测试钙芒硝与淡钙液的反应速率,并提出一定条件下钙芒硝与淡钙液的理想反应量.通过恒温40℃条件下,钙芒硝与去离子水、硝性近饱和卤水、钙性卤水进行一系列溶解对比试验,发现当钙性卤水中主要离子浓度比Na+∶Cl-∶Ca2+为1∶3.37∶1.03时,为最佳溶解组分配比,其最大溶解速率为54.689 g/(m2·h),溶解速率与Na2SO4浓度关系曲线拟合方程y=-8.482Ln(x) +57.362,相关系数R2=0.895.试验结果为探讨研究在岩盐伴生条件下钙芒硝溶解转化利用的最佳开采方案提供依据.%In order to improve the utilization of glauberite within salt rock,dissolving reaction experiment is introduced on low concentration calcium liquid derived from the saline alkali factory and glauberite,aiming at testing their reaction rate and proposing that at which concentration of calcium liquid it can react the best with glauberite on certain conditions.At reaction temperature 40 ℃,glauberite reacts with deionized water,nearly saturated brine containing sodium salt or calcium salt respectively,discovering that the best proportion of Na + ∶ Cl-∶ Ca2 + is 1 ∶ 3.37 ∶1.03,with the highest dissolution rate 54.689g/(m2 · h) whose curve fitting equation with the concentration of Na2SO4 is y =-8.482Ln(x) + 57.362,with its correlation coefficient R2 =0.895.The experiment results provide evidence for investigating the best mining scheme of glauberite within salt rock.

  14. Influence of calcium on the inotropic actions of hyperosmotic agents, norepinephrine, paired electrical stimulation, and treppe.

    Science.gov (United States)

    Willerson, J T; Crie, J S; Adcock, R C; Templeton, G H; Wildenthal, K

    1974-10-01

    To analyze the interaction of calcium ion concentration with hypertonic agents and with other inotropic interventions, isolated right ventricular cat papillary muscles were studied under isometric conditions in Krebs-Ringer bicarbonate solution. Extracellular calcium concentrations were varied between 2.5 and 11.0 mM. Maximal inotropic effects occurred between 5 and 8.0 mM calcium and further elevation to 11.0 mM was without additional influence. The effect of hyperosmotic sucrose and mannitol on papillary muscle performance was compared with that of 10(-6) M norepinephrine at calcium concentrations of 2.5 and 10.0 mM and with paired electrical stimulation in 10.0 mM calcium. Both norepinephrine and the hyperosmotic agents produced significant increases in developed tension and in the maximal rate of tension rise (dT/dt) in Krebs-Ringer in 2.5 and 4.0 mM calcium. In 10 mM calcium norepinephrine increased developed tension and dT/dt, but sucrose and mannitol caused no change or small reductions in both. Paired electrical stimulation, like hyperosmolality, caused no increase in dT/dt in 10 mM calcium. The presence of a potent pharmacological inhibitor of systolic calcium transfer across the cell membrane (D600, 10(-6) M) reduced developed tension and dT/dt by 76+/-2.7 and 74+/-2.0%, respectively, and prevented and in fact reversed the expected increase in dT/dt associated with an increase in rate of stimulation (treppe). However, hypertonic mannitol and paired pacing persisted in causing marked increases in developed tension and dT/dt even in the presence of D600, suggesting that their inotropic effects are not dependent on increased intracellular transfer of calcium during systole through cell membrane channels in which D600 acts as a competitive inhibitor. The results of these studies suggest that apparent functional saturation of intracellular calcium receptor sites eliminates any additional inotropic effect of hyperosmolality or paired pacing. The data are

  15. Comparison of the effect of calcium gluconate and batroxobin on the release of transforming growth factor beta 1 in canine platelet concentrates

    OpenAIRE

    Silva Raul F; Carmona Jorge U; Rezende Cleuza MF

    2012-01-01

    Abstract Background The clinical use of autologous platelet concentrates (also known as platelet-rich plasma) on the field of regenerative therapy, in the last decade has been the subject of several studies especially in equine medicine and surgery. The objectives of this study was: 1) to describe and compare the cellular population in whole blood, lower fraction (A) and upper fraction (B) of platelet concentrates, 2) to measure and compare the transforming growth factor beta 1 (TGF-β1) conce...

  16. Calcium and bones

    Science.gov (United States)

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

  17. Calcium homeostasis in barley aleurone

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.L.

    1990-02-21

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

  18. Impacts of dietary calcium, phytate, and nonphytate phosphorus concentrations in the presence or absence of phytase on inositol hexakisphosphate (IP6) degradation in different segments of broilers digestive tract.

    Science.gov (United States)

    Li, W; Angel, R; Kim, S-W; Brady, K; Yu, S; Plumstead, P W

    2016-03-01

    A total of 1,440 straight-run Heritage 56M × fast-feathering Cobb 500F broiler birds were fed from 11 to 13 d of age to determine the impacts of calcium (Ca), phytate phosphorus (PP), nonphytate P (NPP) and phytase concentrations on the myo-inositol hexakisphosphate (IP6) flow through the different parts of gastrointestinal tract (GIT). The experiment was a 2×2×2×3 randomized block design with 2 Ca (0.7 and 1.0%), 2 PP (0.23 and 0.34%), 2 nPP (0.28 and 0.45%) and 3 phytase (0-, 500-, and 1,000-phytase unit (FTU)/kg) concentrations. The experiment was replicated twice (block) with 3 replicates per treatment (TRT) of 10 birds per block. Concentration of IP6 in crop, proventriculus (PROV) plus (+) gizzard (GIZ) and distal ileum digesta as well as the ileal IP6 disappearance was determined at 13 d of age. In crop, higher IP6 concentration was seen with increased Ca (P IP6 concentration (P IP6 concentration was seen in Prov+Giz (P IP6 disappearance was found at higher Ca (62.3% at 0.7% Ca vs. 57.5% at 1.0% Ca; P IP6 degradation but the degree of impact was dependent on nPP and PP (P IP6 concentration and IP6 disappearance in distal ileum regardless of GIT segments or diet composition, but impacts of dietary Ca, nPP, and PP differed depending on GIT segment examined. © The Author 2016. Published by Oxford University Press on behalf of Poultry Science Association.

  19. Calcium Carbonate

    Science.gov (United States)

    ... doctor if you have or have ever had kidney disease or stomach conditions.tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking calcium carbonate, call your doctor.

  20. Calcium Test

    Science.gov (United States)

    ... if a person has symptoms of a parathyroid disorder , malabsorption , or an overactive thyroid. A total calcium level is often measured as part of a routine health screening. It is included in the comprehensive metabolic panel (CMP) and the basic metabolic panel (BMP) , ...

  1. Carbohydrate-Carbohydrate Interactions Mediated by Sulfate Esters and Calcium Provide the Cell Adhesion Required for the Emergence of Early Metazoans

    National Research Council Canada - National Science Library

    Vilanova, Eduardo; Santos, Gustavo R C; Aquino, Rafael S; Valle-Delgado, Juan J; Anselmetti, Dario; Fernàndez-Busquets, Xavier; Mourão, Paulo A S

    2016-01-01

    .... Cell adhesion in sponges is mediated by the calcium-dependent multivalent self-interactions of sulfated polysaccharides components of extracellular membrane-bound proteoglycans, namely aggregation factors...

  2. Comparison of renal calcium concentration in obese, lean, diabetic, and non-diabetic Zucker rats fed a magnesium-deficient fructose diet.

    Science.gov (United States)

    Koh, E T; Min, K W; Scholfield, D J; Sarkarcadeh, A

    1991-01-01

    In order to determine the effects of hypoinsulinaemia or hyperinsulinaemia on nephrocalcinosis induced by the interaction between fructose and magnesium (Mg) deficiency, we compared kidney calcification in obese versus lean, and non-diabetic versus diabetic female Zucker rats fed a magnesium-deficient fructose diet. One half of the obese and lean animals, respectively, was injected with streptozotocin to produce diabetes, and the other half was injected with citrate buffer alone. Diabetic, non-diabetic, obese, and lean animals were divided into two dietary groups, consisting of high starch or high fructose without added Mg. After a four week period, 24 hour urine was collected for urinary output, protein, oxalate, citrate, MG, and calcium (Ca) measurements. The animals were then decapitated, and blood was collected for glucose, Mg, and Ca determinations, and kidneys were removed to determine their Mg and Ca contents. All fructose-fed animals exhibited significantly more kidney Ca then the starch-fed animals. Lean non-diabetic rats fed fructose showed the greatest kidney Ca along with the greatest urinary protein excretion among all experimental groups. The significant finding in the present study is that diabetes or obesity reduced nephrocalcinosis regardless of the insulin status of the rats. Diuresis and hypercitraturia in diabetic and/or obese animals may cause a reduction in nephrocalcinosis induced by the interaction between fructose and magnesium deficiency. Hyperproteinuria (uromucoid) in combination with hypercalciuria and hypomagnesuria may be responsible for greater nephrocalcinosis in the fructose than the starch group. The possible mechanisms for this interaction on nephrocalcinosis have been discussed.

  3. The calcium-sensing receptor and the parathyroid: past, present, future

    Directory of Open Access Journals (Sweden)

    Arthur David Conigrave

    2016-12-01

    Full Text Available Parathyroid hormone (PTH defends the extracellular fluid from hypocalcemia and has powerful and well-documented actions on the skeleton and renal tubular system. To achieve a satisfactory stable plasma calcium level, the secretion of PTH, and the resulting serum PTH level, is titrated carefully to the prevailing plasma ionized Ca2+ concentration via a Ca2+ sensing mechanism that mediates feedback inhibition of PTH secretion. Herein, I consider the properties of the parathyroid Ca2+ sensing mechanism, the identity of the Ca2+ sensor, the intracellular biochemical mechanisms that it controls, the manner of its integration with other components of the PTH secretion control mechanism, and its modulation by other nutrients. Together the well established, recently elucidated, and yet-to-be discovered elements of the story constitute the past, present, and future of the parathyroid and its calcium-sensing receptor (CaSR.

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

    Science.gov (United States)

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

    1997-01-01

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

  5. NMDAR1 mRNA expression and glutamate receptor stimulated increase in cytosolic calcium concentration in rat and mouse cerebellar granule cells

    DEFF Research Database (Denmark)

    Mogensen, H S; Jørgensen, Ole Steen

    1996-01-01

    RNA and was normalized to that of the constitutively expressed H3.3 histone mRNA. The glutamate and NMDA stimulated increase in cytosolic Ca(2+)-ion concentration was measured using the fluorescent Ca(2+)-chelator Fluo3. In contrast to the hypothesis, we found NMDAR1 mRNA expression to be lower in mouse than in rat...

  6. The Association Between Calcium, Magnesium, and Ratio of Calcium/Magnesium in Seminal Plasma and Sperm Quality.

    Science.gov (United States)

    Liang, Hong; Miao, Maohua; Chen, Jianping; Chen, Kanglian; Wu, Bin; Dai, Qi; Wang, Jian; Sun, Fei; Shi, Huijuan; Yuan, Wei

    2016-11-01

    The study aimed to examine the relationships between calcium, magnesium, and calcium/magnesium ratio in semen plasma and sperm quality. It was a cross-sectional study based on a program aiming at promoting the reproductive health in less-developed areas. A total of 515 men aged between 18 and 55 years provided semen specimens at family planning clinics in Sandu County, Guizhou Province, China. Total calcium and magnesium concentrations in semen plasma were measured with flame atomic absorption spectrometry. Sperm quality, including sperm motility and concentration, was evaluated by using a computer-assisted sperm analysis method. The medians of seminal plasma calcium, magnesium, and zinc concentrations were 9.61, 4.41, and 2.23 mmol/l, respectively. Calcium concentration and calcium/magnesium ratio were negatively associated with sperm concentrations (β = -0.47, P = 0.0123 for calcium; β = -0.25, P = 0.0393 for calcium/magnesium ratio) after adjusting for zinc and other covariates. In stratified analyses, the association between calcium and sperm concentrations only persisted among subjects with a calcium/magnesium ratio of ≤2.5 (β = -0.71, P = 0.0268). In the same stratum, magnesium was associated with increased sperm concentration (β = 0.73, P = 0.0386). Among subjects with a calcium/magnesium ratio of >2.5, neither calcium nor magnesium was associated with sperm concentration. In conclusion, total calcium and magnesium concentrations were associated with sperm concentration among subjects with a lower calcium/magnesium ratio. The calcium and magnesium ratio had a modifying effect on the associations of calcium and magnesium with sperm concentration.

  7. Plasma membrane calcium flux, protein kinase C activation and smooth muscle contraction.

    Science.gov (United States)

    Forder, J; Scriabine, A; Rasmussen, H

    1985-11-01

    Isolated perfused rabbit ear arteries contract when treated with 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of the calcium-activated, phospholipid-dependent protein kinase or C-kinase. Under conditions where the calcium concentration in the perfusate is 1.5 mM and the potassium concentration is 4.8 mM, there is a latent period of 70 +/- 19 min (mean +/- S.E.M., n = 10) between TPA addition and the onset of the contractile response. Once initiated, the contractile response is progressive and sustained. When perfusion conditions are altered in such a way as to modify calcium flux across the plasma membrane (i.e., raising the extracellular calcium concentration to 2.5 mM Ca++, raising the extracellular potassium concentration to 10 mM, and/or preincubating the tissues in media containing 100 nM Bay K 8644, a potent calcium channel agonist), the latency period between TPA addition and initiation of the contractile response is significantly reduced (2.5 mM Ca++, 37 +/- 7 min; 10 mM K+ and 2.5 mM Ca++, 11 +/- 3 min; 100 nM Bay K 8644 and 1.5 mM Ca++, 20 +/- 7 min; 100 nM Bay K 8644 and 2.5 mM Ca2+, 8.5 +/- 1.7 min; 10 mM K+ and 100 nM Bay K 8644, 11 +/- 5 min). Likewise, the combination of 2.5 mM calcium, 100 nM Bay K 8644, and 3.3 microM ouabain results in a contractile response 4.5 +/- 2.0 min after TPA addition (means +/- S.E.M., n = 4). Control tissues (absence of TPA addition) run simultaneously show no contractile responses to the various Ca++ flux regulators even after 90 min of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Dense spermatozoa in stallion ejaculates contain lower concentrations of mRNAs encoding the sperm specific calcium channel 1, ornithine decarboxylase antizyme 3, aromatase, and estrogen receptor alpha than less dense spermatozoa.

    Science.gov (United States)

    Ing, N H; Forrest, D W; Love, C C; Varner, D D

    2014-07-15

    Stallions are unique among livestock in that, like men, they commonly receive medical treatment for subfertility. In both species, about 15% of individuals have normal semen parameters but are subfertile, indicating a need for novel analyses of spermatozoa function. One procedure for improving fertilizing capability of stallions and men is isolation of dense spermatozoa from an ejaculate for use in artificial insemination. In the current study, dense and less dense spermatozoa were purified by density gradient centrifugation from individual ejaculates from seven reproductively normal adult stallions. The RNA isolated from the spermatozoa seemed to be naturally fragmented to an average length of 250 bases, consistent with reports of spermatozoa RNA from other species. The DNAse treatment of RNA prepared from spermatozoa removed any genomic DNA contamination, as assessed by PCR with intron spanning primers for the protamine 1 (PRM1) gene. Concentrations of seven mRNAs in spermatozoa, correlated with the fertility of men and bulls, were quantified by reverse transcription polymerase chain reaction in dense and less dense spermatozoa. Concentrations of four mRNAs were two- to four-fold lower in dense spermatozoa compared with less dense spermatozoa: Encoding the spermatozoa-specific calcium channel (P 0.1). These results identify new differences in mRNA concentrations in populations of spermatozoa with dissimilar densities.

  9. 不同种类饮料对青少年牙釉质钙浓度的影响%Comparative study of influence of soft drinks to calcium concentration of young permanent teeth enamel

    Institute of Scientific and Technical Information of China (English)

    彭杰; 柳洪周; 张敏; 谢霓; 朱友家

    2014-01-01

    目的:探讨三种不同的碳酸饮料对我国14岁以下青少年的牙釉质中钙浓度的影响。方法:收集在我院进行减数拔牙的14岁以下青少年的第一前磨牙30颗进行研究。从超市购买同批次的雪碧,百事可乐和冰茶进行试验。首先,使用全自动生化分析仪(Olympus AU5400)对购买的三种饮料进行检测,确定其钙离子的浓度。使用购买的同批次的各种碳酸饮料对标本进行浸泡,浸泡时间为1周,取出,对浸泡后的牙齿使用显微硬度仪进行牙釉质硬度的检测,对浸泡后的溶液,使用全自动生化分析仪进行钙浓度的检测,比较浸泡后的牙釉质和浸泡前牙釉质的硬度变化和饮料中钙离子浓度的变化。结果:购买的饮料中雪碧的钙浓度为0.57 mmol/L,百事可乐的钙离子浓度为0.93 mmol/L,冰茶的钙离子浓度为0.18 mmol/L。三种饮料均能导致牙釉质中钙离子的溶出。不同种类饮料导致牙釉质中钙离子溶出的量不同,差异具有统计学意义(P<0.05)。显微硬度仪的检测,发现经过三种饮料处理的牙齿硬度均下降,差异具有统计学意义(P<0.05)。结论:三种饮料都能导致牙釉质脱矿,其中可乐的脱矿作用最强。%Objective:To compare the effect three kinds of drinks to the enamel calcium concentration. Method:The calcium concentration of three drinks was analyzed by Olympus AU5400,and then the enamel was immersed in drinks for a week. The calcium concentrations in the drinks after immersion of the enamel were analyzed by Olympus AU5400. The hard of enamel was analysis by micro-hardness machine. Result:The level of calcium of Sprite,Pepsi,and Tea was 0.57 mmol/L,0.93 mmol/L,and 0.18 mmol/L. All the drinks had dematerializing effect on enamel and decreased the surface micro-hardness of enamel. There were significant differences in different drinks. Conclusion:Three drinks may have erosive

  10. Effect of concentration and substrate flow rate on isomaltulose production from sucrose by Erwinia sp. cells immobilized in calcium-alginate using packed bed reactor.

    Science.gov (United States)

    Kawaguti, Haroldo Yukio; Harumi Sato, Hélia

    2010-09-01

    Isomaltulose was obtained from sucrose solution by immobilized cells of Erwinia sp. D12 using a batch and a continuous process. Parameters for sucrose conversion into isomaltulose were evaluated using both experimental design and response surface methodology. Erwinia sp. D12 cells were immobilized in different alginates, and the influence of substrate flow rate and concentration parameters to produce isomaltulose from sucrose were observed. Response surface methodology demonstrated that packed bed columns containing cells immobilized in low-viscosity sodium alginate (250 cP) presented a mean isomaltulose conversion rate of 47%. In a continuous process, both sucrose substrate concentration and substrate flow rate parameters had a significant effect (p < 0.05) and influenced the conversion of sucrose into isomaltulose. Higher conversion rates of sucrose into isomaltulose, from 53-75% were obtained using 75 g of immobilized cells at a substrate flow rate of 0.6 mL/min.

  11. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  12. Sodium-dependent phosphate uptake in the jejunum is post-transcriptionally regulated in pigs fed a low-phosphorus diet and is independent of dietary calcium concentration.

    Science.gov (United States)

    Saddoris, Kari L; Fleet, James C; Radcliffe, John S

    2010-04-01

    In rodents, severe dietary P restriction increases active phosphate absorption by the intestine. However, it remains unknown if moderate dietary P restriction has a similar effect. Weanling pigs (n = 32; body weight 7.4 +/- 0.55 kg) were used in a 2 x 2 factorial design and fed dietary available P (aP) concentrations of 0.23 or 0.40% and Ca concentrations of 0.58 or 1.00% for 14 d. Diets were formulated on an aP basis instead of a total P basis, because pigs are unable to absorb phytate-P present in corn and soybean meal. Jejunal segments were mounted in modified Ussing chambers for determination of Na(+)-dependent nutrient transport. Intestinal mucosal scrapings were taken for RNA isolation and brush border membrane (BBM) vesicle isolation. Na(+)-dependent phosphate uptake and gene expression of Na-phosphate cotransporter IIb (NaPi-IIb), SGLT-1 (sodium/glucose cotransporter-1), and calbindin D(9k) and protein expression of NaPi-IIb were evaluated. Na(+)-dependent phosphate transport increased (P dietary aP concentration was decreased. However, increased Na(+)-dependent phosphate uptake was not accompanied by increased NaPi-IIb mRNA expression. Expression of NaPi-IIb protein in the BBM increased (P pigs fed low-P diets compared with pigs fed adequate-P diets. No dietary Ca effects or aP x Ca interactions were detected for Na-dependent P uptake, mRNA or protein expression of NaPi-IIb, or mRNA expression of calbindin D(9k). These data suggest that restricting dietary aP concentration by only 43% stimulates Na(+)-dependent phosphate uptake and expression of the NaPi-IIb protein in the BBM of the small intestine and through a post-transcriptional mechanism.

  13. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

  14. Regulation of Synaptic Transmission by Ambient Extracellular Glutamate

    OpenAIRE

    Featherstone, David E.; Scott A. Shippy

    2007-01-01

    Many neuroscientists assume that ambient extracellular glutamate concentrations in the nervous system are biologically negligible under nonpathological conditions. This assumption is false. Hundreds of studies over several decades suggest that ambient extracellular glutamate levels in the intact mammalian brain are ~0.5 to ~5 μM. This has important implications. Glutamate receptors are desensitized by glutamate concentrations significantly lower than needed for receptor activation; 0.5 to 5 μ...

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

    Science.gov (United States)

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

    1996-08-01

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

  16. Calcium sensing receptors and calcium oscillations: calcium as a first messenger.

    Science.gov (United States)

    Breitwieser, Gerda E

    2006-01-01

    Calcium sensing receptors (CaR) are unique among G-protein-coupled receptors (GPCRs) since both the first (extracellular) and second (intracellular) messengers are Ca(2+). CaR serves to translate small fluctuations in extracellular Ca(2+) into intracellular Ca(2+) oscillations. In many cells and tissues, CaR also acts as a coincidence detector, sensing both changes in extracellular Ca(2+) plus the presence of various allosteric activators including amino acids, polyamines, and/or peptides. CaR oscillations are uniquely shaped by the activating agonist, that is, Ca(2+) triggers sinusoidal oscillations while Ca(2+) plus phenylalanine trigger transient oscillations of lower frequency. The distinct oscillation patterns generated by Ca(2+)versus Ca(2+) plus phenylalanine are the results of activation of distinct signal transduction pathways. CaR is a member of Family C GPCRs, having a large extracellular agonist binding domain, and functioning as a disulfide-linked dimer. The CaR dimer likely can be driven to distinct active conformations by various Ca(2+) plus modulator combinations, which can drive preferential coupling to divergent signaling pathways. Such plasticity with respect to both agonist and signaling outcomes allows CaR to uniquely contribute to the physiology of organs and tissues where it is expressed. This chapter will examine the structural features of CaR, which contribute to its unique properties, the nature of CaR-induced intracellular Ca(2+) signals and the potential role(s) for CaR in development and differentiation.

  17. Hemodynamic effects of calcium gluconate administered to conscious horses.

    Science.gov (United States)

    Grubb, T L; Foreman, J H; Benson, G J; Thurmon, J C; Tranquilli, W J; Constable, P D; Olson, W O; Davis, L E

    1996-01-01

    Calcium gluconate was administered to conscious horses at 3 different rates (0.1, 0.2, and 0.4 mg/kg/min for 15 minutes each). Serum calcium concentrations and parameters of cardiovascular function were evaluated. All 3 calcium administration rates caused marked increases in both ionized and total calcium concentrations, cardiac index, stroke index, and cardiac contractility (dP/dtmax). Mean arterial pressure and right atrial pressure were unchanged; heart rate decreased markedly during calcium administration. Ionized calcium concentration remained between 54% and 57% of total calcium concentration throughout the study. We conclude that calcium gluconate can safely be administered to conscious horses at 0.1 to 0.4 mg/kg/min and that administration will result in improved cardiac function.

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

    Science.gov (United States)

    Jorgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne; Civitelli, Roberto; Sorensen, Ole Helmer; Steinberg, Thomas H.

    2003-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  20. 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...

  1. The coupling of acetylcholine-induced BK channel and calcium channel in guinea pig saccular type II vestibular hair cells.

    Science.gov (United States)

    Kong, Wei-Jia; Guo, Chang-Kai; Zhang, Xiao-Wen; Chen, Xiong; Zhang, Song; Li, Guan-Qiao; Li, Zhi-Wang; Van Cauwenberge, Paul

    2007-01-19

    Molecular biological studies and electrophysiological data have demonstrated that acetylcholine (ACh) is the principal cochlear and vestibular efferent neurotransmitter among mammalians. However, the functional roles of ACh in type II vestibular hair cells (VHCs II) among mammalians are still unclear, with the exception of the well-known alpha9-containing nicotinic ACh receptor (alpha9-containing nAChR)-activated small conductance, calcium-dependent potassium current (SK) in cochlear hair cells and frog saccular hair cells. The activation of SK current was necessary for the calcium influx through the alpha9-containing nAChR. Recently, we have demonstrated that ACh-induced big conductance, calcium-dependent potassium current (BK) was present in VHCs II of the vestibular end-organ of guinea pig. In this study, the nature of calcium influx for the activation of ACh-induced BK current in saccular VHCs II of guinea pig was investigated. Following extracellular perfusion of ACh, saccular VHCs II displayed a sustained outward current, which was sensitive to iberiotoxin (IBTX). High concentration of apamin failed to inhibit the current amplitude of ACh-induced outward current. Intracellular application of Cs(+) completely abolished the current evoked by ACh. ACh-induced current was potently inhibited by nifedipine, nimodipine, Cd(2+) and Ni(2+), respectively. The inhibition potency of these four calcium channel antagonists was nimodipine>nifedipine>cadmium>nickel. The L-type Ca(2+) channels agonist, (-)-Bay-K 8644 mimicked the effect of ACh and activated an IBTX-sensitive current. In addition, partial VHCs II displayed a biphasic waveform. In conclusion, the present data showed that in the guinea pig saccular VHCs II, ACh-induced BK channel was coupled with the calcium channel, but not the receptor. The perfusion of ACh will drive the opening of calcium channels; the influx of calcium ions will then activate the BK current.

  2. Induced calcium carbonate precipitation using Bacillus species.

    Science.gov (United States)

    Seifan, Mostafa; Samani, Ali Khajeh; Berenjian, Aydin

    2016-12-01

    Microbially induced calcium carbonate precipitation is an emerging process for the production of self-healing concrete. This study was aimed to investigate the effects and optimum conditions on calcium carbonate biosynthesis. Bacillus licheniformis, Bacillus sphaericus, yeast extract, urea, calcium chloride and aeration were found to be the most significant factors affecting the biomineralization of calcium carbonate. It was noticed that the morphology of microbial calcium carbonate was mainly affected by the genera of bacteria (cell surface properties), the viscosity of the media and the type of electron acceptors (Ca(2+)). The maximum calcium carbonate concentration of 33.78 g/L was achieved at the optimum conditions This value is the highest concentration reported in the literature.

  3. Calcium aluminate in alumina

    Science.gov (United States)

    Altay, Arzu

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

  4. A mathematical model of T lymphocyte calcium dynamics derived from single transmembrane protein properties

    Directory of Open Access Journals (Sweden)

    Christine Dorothee Schmeitz

    2013-09-01

    Full Text Available Fate decision processes of T lymphocytes are crucial for health and disease. Whether a T lymphocyte is activated, divides, gets anergic or initiates apoptosis depends on extracellular triggers and intracellular signalling. Free cytosolic calcium dynamics plays an important role in this context. The relative contributions of store-derived calcium entry and calcium entry from extracellular space to T lymphocyte activation are still a matter of debate. Here we develop a quantitative mathematical model of T lymphocyte calcium dynamics in order to establish a tool which allows to disentangle cause-effect relationships between ion fluxes and observed calcium time courses. The model is based on single transmembrane protein characteristics which have been determined in independent experiments. This reduces the number of unknown parameters in the model to a minimum and ensures the predictive power of the model. Simulation results are subsequently used for an analysis of whole cell calcium dynamics measured under various experimental conditions. The model accounts for a variety of these conditions, which supports the suitability of the modelling approach. The simulation results suggest a model in which calcium dynamics dominantly relies on the opening of channels in calcium stores while calcium entry through calcium-release activated channels (CRAC is more associated with the maintenance of the T lymphocyte calcium levels and prevents the cell from calcium depletion. Our findings indicate that CRAC guarantees a long-term stable calcium level which is required for cell survival and sustained calcium enhancement.

  5. Extraction and concentration of biogenic calcium oxalate from plant leaves Extração e concentração de oxalato de cálcio biogênico de folhas de plantas

    Directory of Open Access Journals (Sweden)

    Liovando Marciano da Costa

    2009-06-01

    Full Text Available The objective of this study was to extract and concentrate calcium oxalate (CaOx crystals from plant leaves that form the above mentioned crystals. The chemical and physical studies of CaOx from plant to be performed depend on an adequate amount of the crystals. The plant used in this study was croton (Codiaeum variegatum. The leaves were ground in a heavy duty blender and sieved through a 0.20 mm sieve. The suspension obtained was suspended in distilled water. The crystals were concentrated at the bottom of a test tube. The supernatant must be washed until it is free of plant pigments and other organic substances. Biogenic CaOx crystals have well-defined and sharp peaks, indicating very high crystallinity. Moreover, the CaOx crystals were not damaged during the extraction procedure, as can be seen on the scanning electron microscope images. The porposed method can be considered efficient to extract and concentrate biogenic calcium oxalate.O objetivo deste estudo foi extrair e concentrar cristais de oxalato de cálcio (CaOx a partir de folhas de plantas que formam os cristais mencionados. Os estudos químicos e físicos de CaOx de plantas a serem realizados demandam uma massa adequada dos cristais. A planta usada neste estudo foi o cróton (Codiaeum variegatum. As folhas foram trituradas por um liquidificador industrial e peneiradas em peneira de 0,20 mm. Ao suco obtido foi adicionada água destilada. Os cristais foram concentrados no fundo da proveta. É necessário manter a lavagem dos cristais até que o sobrenadante fique livre de pigmentos de plantas e outras substâncias orgânicas. Os cristais de CaOx apresentaram picos bem formados e estreitos, indicando que sua cristalinidade é muito alta; além disso, esses cristais não foram danificados durante o procedimento de extração, o que pode ser visto observando-se as fotos obtidas pelo microscópio eletrônico de varredura. O método apresentado pode ser considerado eficiente para extrair

  6. 100-NR-2 Apatite Treatability Test: High-Concentration Calcium-Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Vermeul, Vincent R.; Fritz, Brad G.; Fruchter, Jonathan S.; Szecsody, James E.; Williams, Mark D.

    2010-09-01

    Following an evaluation of potential strontium-90 (90Sr) treatment technologies and their applicability under 100-NR-2 hydrogeologic conditions, the U.S. Department of Energy (DOE), Fluor Hanford, Inc. (now CH2M Hill Plateau Remediation Company [CHPRC]), Pacific Northwest National Laboratory, and the Washington State Department of Ecology agreed that the long-term strategy for groundwater remediation at the 100-N Area should include apatite as the primary treatment technology. This agreement was based on results from an evaluation of remedial alternatives that identified the apatite permeable reactive barrier (PRB) technology as the approach showing the greatest promise for reducing 90Sr flux to the Columbia River at a reasonable cost. This letter report documents work completed to date on development of a high-concentration amendment formulation and initial field-scale testing of this amendment solution.

  7. Carbachol and KCl-induced changes in intracellular free calcium concentration in isolated, fura-2 loaded smooth-muscle cells from the anterior byssus retractor muscle of Mytilus edulis.

    Science.gov (United States)

    Ishii, N; Simpson, A W; Ashley, C C

    1988-06-16

    Intracellular free calcium concentration [( Ca2+]1) was measured in suspensions of fura-2 loaded smooth-muscle cells isolated from the anterior byssus retractor muscle of Mytilus edulis. Successive application of 5mM carbachol (CCh) and 100mM KCl to the cells transiently elevated [Ca2+]1 from the resting value of 124 +/- 4.5nM (mean +/- S.E., n = 14) to 295 +/- 15.3 and 383 +/- 20.5 nM, respectively. The response to CCh was concentration-dependent with an ED50 of 10(-5) M. Under the microscope, 67 +/- 3.0 and 83 +/- 1.3 % of fura-2 loaded cells contracted on the addition of 5mM CCh and 100mM KCl, respectively. In Ca2+ -free sea water, the CCh induced change in [Ca2+]1 was partially suppressed whereas that induced by KCl was completely abolished, suggesting an agonist-evoked release of stored Ca2+.

  8. NMDAR-mediated calcium transients elicited by glutamate co-release at developing inhibitory synapses

    Directory of Open Access Journals (Sweden)

    Abigail Kalmbach

    2010-07-01

    Full Text Available Before hearing onset, the topographic organization of the inhibitory sound localization pathway from the medial nucleus of the trapezoid body (MNTB to the lateral superior olive (LSO is refined by means of synaptic silencing and strengthening. During this refinement period MNTB-LSO synapses not only release GABA and glycine but also release glutamate. This co-released glutamate can elicit postsynaptic currents that are predominantly mediated by NMDA receptors (NMDARs. To gain a better understanding of how glutamate contributes to synaptic signaling at developing MNTB-LSO inhibitory synapse, we investigated to what degree and under what conditions NMDARs contribute to postsynaptic calcium responses. Our results demonstrate that MNTB-LSO synapses can elicit compartmentalized calcium responses along aspiny LSO dendrites. These responses are significantly attenuated by the NMDARs antagonist APV. APV, however, has no effect on somatically recorded electrical postsynaptic responses, indicating little, if any, contribution of NMDARs to spike generation. Small NMDAR-mediated calcium responses were also observed under physiological levels of extracellular magnesium concentrations indicating that MNTB-LSO synapses activate magnesium sensitive NMDAR on immature LSO dendrites. In Fura-2 AM loaded neurons, blocking GABAA and glycine receptors decreased NMDAR contribution to somatic calcium responses suggesting that GABA and glycine, perhaps by shunting backpropagating action potentials, decrease the level of NMDAR activation under strong stimulus conditions.

  9. Effects of tocainide and lidocaine on the transmembrane action potentials as related to external potassium and calcium concentrations in guinea-pig papillary muscles.

    Science.gov (United States)

    Oshita, S; Sada, H; Kojima, M; Ban, T

    1980-10-01

    Effects of lidocaine and tocainide on transmembrane potentials were studied in isolated guinea-pig papillary muscles, superfused with modified Tyrode's solution containing either 5.4, 2.7, 10.0 or 8.1 mmol/l potassium concentration, [K]0. The last solution applied contained either 1.8 (normal [Ca]0) or 7.2 mmol/l [Ca]0 (high [Ca]0. The concentrations of lidocaine and tocainide used were 18.5, 36.9 and 73.9 mumol/l and 43.7, 87.5 and 174.9 mumol/l in 5.4 mmol/l [K]0 solution and 36.9 and 87.5 mumol/l in the other solutions, respectively. At the driving rate of 1 Hz in 5.4 mmol/l "K]0 solution, both drugs produced dose-dependently a reduction of maximum rate of rise of action potential (Vmax), together with a prolongation of the relative refractory period. Vmax decreased progressively as the driving rate was increased from 1 Hz (for lidocaine) and from 0.25 Hz (for tocainide) to 5 Hz. This action was accentuated dose-dependently. A slow component (time constant tau = 232 ms for lidocaine, 281--303 ms for tocainide) and slower component (tau = 2.1--3.8 s for tocainide) of the recovery (reactivation) of Vmax were observed in premature responses at 0.25 Hz and in the first response after interruption of the basic driving rate at 1 Hz. All these effects were accentuated with rising [K]0 and attenuated in the high [Ca]0 solution. Both drugs abbreviated the action potential duration at 50% (APD50) and 90% (APD90) levels at 5.4, 8.1 and 10.0 mmol/l [K]0 but not at 2.7 mmol/l [K]0 nor a high [Ca]0 at 1 Hz. These [K]0-dependent effects of lidocaine on Vmax were successfully simulated by the model proposed by Hondeghem and Katzung (1977), with a slight change in parameter values. The mode of interaction of lidocaine with sodium channels in the open, closed and rested states was deduced from these results.

  10. Hydrothermal growth of TiO{sub 2}-CaP nano-films on a Ti–Nb-based alloy in concentrated calcium phosphate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongwei, E-mail: lihw74@foxmail.com [Chang’an University, School of Materials Science and Engineering (China); Fu, Tao, E-mail: taofu@mail.xjtu.edu.cn [Xi’an Jiaotong University, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology (China); Li, Wen [Chang’an University, School of Materials Science and Engineering (China); Alajmi, Zafer; Sun, Jiamao [Xi’an Jiaotong University, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology (China)

    2016-01-15

    The Ti–Nb-based TLM alloy (Ti–25Nb–3Zr–2Sn–3Mo) was subjected to hydrothermal treatment in the concentrated Ca{sub 3}(PO{sub 4}){sub 2}, CaHPO{sub 4}, and Ca(H{sub 2}PO{sub 4}){sub 2} solutions for the purpose of calcification. The treated samples are covered by films consisting of Ca-rich nano-crystallites (100–500 nm) and small nano-grains. XPS and XRD analyses reveal the formation of hydroxyapatite, TiO{sub 2}, and Nb{sub 2}O{sub 5} at the sample surface. The sample hydrothermally treated in CaHPO{sub 4} solution exhibits bioactivity by inducing the formation of apatite layer after soaking test in the simulated body fluid for 15 days. The work would provide a good bioactive surface modification method for Ti–Nb alloy implants with complex shapes and even pores.

  11. Interim Report: 100-NR-2 Apatite Treatability Test: Low Concentration Calcium Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mark D.; Fritz, Brad G.; Mendoza, Donaldo P.; Rockhold, Mark L.; Thorne, Paul D.; Xie, YuLong; Bjornstad, Bruce N.; Mackley, Rob D.; Newcomer, Darrell R.; Szecsody, James E.; Vermeul, Vincent R.

    2008-07-11

    Following an evaluation of potential Sr-90 treatment technologies and their applicability under 100-NR-2 hydrogeologic conditions, U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory, and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at 100-N Area will include apatite sequestration as the primary treatment, followed by a secondary treatment if necessary (most likely phytoremediation). Since then, the agencies have worked together to agree on which apatite sequestration technology has the greatest chance of reducing Sr-90 flux to the river at a reasonable cost. In July 2005, aqueous injection, (i.e., the introduction of apatite-forming chemicals into the subsurface) was endorsed as the interim remedy and selected for field testing. Studies are in progress to assess the efficacy of in situ apatite formation by aqueous solution injection to address both the vadose zone and the shallow aquifer along the 300 ft of shoreline where Sr-90 concentrations are highest. This report describes the field testing of the shallow aquifer treatment.

  12. Activity-dependent changes in extracellular Ca2+ and K+ reveal pacemakers in the spinal locomotor-related network.

    Science.gov (United States)

    Brocard, Frédéric; Shevtsova, Natalia A; Bouhadfane, Mouloud; Tazerart, Sabrina; Heinemann, Uwe; Rybak, Ilya A; Vinay, Laurent

    2013-03-20

    Changes in the extracellular ionic concentrations occur as a natural consequence of firing activity in large populations of neurons. The extent to which these changes alter the properties of individual neurons and the operation of neuronal networks remains unknown. Here, we show that the locomotor-like activity in the isolated neonatal rodent spinal cord reduces the extracellular calcium ([Ca(2+)]o) to 0.9 mM and increases the extracellular potassium ([K(+)]o) to 6 mM. Such changes in [Ca(2+)]o and [K(+)]o trigger pacemaker activities in interneurons considered to be part of the locomotor network. Experimental data and a modeling study show that the emergence of pacemaker properties critically involves a [Ca(2+)]o-dependent activation of the persistent sodium current (INaP). These results support a concept for locomotor rhythm generation in which INaP-dependent pacemaker properties in spinal interneurons are switched on and tuned by activity-dependent changes in [Ca(2+)]o and [K(+)]o.

  13. Influence of reactive oxygen species and RhoA/ROCK pathway on calcium concentration and calcium sensitivity of vascular smooth muscle cells%活性氧与 RhoA/ROCK 信号通路对血管平滑肌细胞钙浓度及钙敏感性的影响

    Institute of Scientific and Technical Information of China (English)

    闫莹; 杨朝; 汪涛

    2015-01-01

    Reactive oxygen species (ROS)is an important class of second messengers in vivo,and can be induced greatly by ischemia and hypoxia.Hypoxia signal can trigger the contraction of vascular smooth muscle cells by regulating the cytoplasmic free calcium concentration via ROS,hypoxia may also activate RhoA/ROCK signaling pathway by ROS and then regulate the calcium sensitivity.Deep research on ROS and RhoA/ROCK pathway will illustrate the pathogenesis of hypoxic pulmonary vasoconstriction and pulmonary hypertension,providing new ideas for the treatment of hypoxic pulmonary hypertension.%活性氧(ROS)是体内一类重要的第二信使,能在缺血缺氧的诱导下大量产生。缺氧信号能通过 ROS 调节血管平滑肌细胞内的钙浓度,从而引起其收缩反应;缺氧还有可能通过 ROS 激活 RhoA/ROCK 信号通路,对钙敏感性进行调节。对 ROS 以及 RhoA/ROCK 信号通路进行深入的研究,可以阐明缺氧性肺血管收缩以及肺动脉高压的发病机制,为缺氧性肺动脉高压的治疗提供新的思路。

  14. Extracellular matrix structure.

    Science.gov (United States)

    Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K

    2016-02-01

    Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented.

  15. Clinically relevant concentration of pregabalin has no acute inhibitory effect on excitation of dorsal horn neurons under normal or neuropathic pain conditions: An intracellular calcium-imaging study in spinal cord slices from adult rats.

    Science.gov (United States)

    Baba, Hiroshi; Petrenko, Andrey B; Fujiwara, Naoshi

    2016-10-01

    Pregabalin is thought to exert its therapeutic effect in neuropathic pain via binding to α2δ-1 subunits of voltage-gated calcium (Ca(2+)) channels. However, the exact analgesic mechanism after its binding to α2δ-1 subunits remains largely unknown. Whether a clinical concentration of pregabalin (≈10μM) can cause acute inhibition of dorsal horn neurons in the spinal cord is controversial. To address this issue, we undertook intracellular Ca(2+)-imaging studies using spinal cord slices with an intact attached L5 dorsal root, and examined if pregabalin acutely inhibits the primary afferent stimulation-evoked excitation of dorsal horn neurons in normal rats and in rats with streptozotocin-induced painful diabetic neuropathy. Under normal conditions, stimulation of a dorsal root evoked Ca(2+) signals predominantly in the superficial dorsal horn. Clinically relevant (10μM) and a very high concentration of pregabalin (100μM) did not affect the intensity or spread of dorsal root stimulation-evoked Ca(2+) signals, whereas an extremely high dose of pregabalin (300μM) slightly but significantly attenuated Ca(2+) signals in normal rats and in diabetic neuropathic (DN) rats. There was no difference between normal rats and DN rats with regard to the extent of signal attenuation at all concentrations tested. These results suggest that the activity of dorsal horn neurons in the spinal cord is not inhibited acutely by clinical doses of pregabalin under normal or DN conditions. It is very unlikely that an acute inhibitory action in the dorsal horn is the main analgesic mechanism of pregabalin in neuropathic pain states. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. l-Amino acid sensing by the extracellular Ca2+-sensing receptor

    OpenAIRE

    Conigrave, Arthur D; Quinn, Stephen J.; Brown, Edward M.

    2000-01-01

    The extracellular calcium (Ca2+o)-sensing receptor (CaR) recognizes and responds to (i.e., “senses”) Ca2+o as its principal physiological ligand. In the present studies, we document that the CaR is activated not only by extracellular calcium ions but also by amino acids, establishing its capacity to sense nutrients of two totally different classes. l-Amino acids, especially aromatic amino acids, including l-phenylalanine and l-tryptophan, stereoselectively mobilized Ca2+ ions in the presence ...

  17. 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

  18. Precipitation and Solubility of Calcium Hydrogenurate Hexahydrate.

    Science.gov (United States)

    Babić-Ivančić, V; Füredi-Milhofer, H; Brničević, N; Marković, M

    1992-01-01

    Solid phases formed in the quaternary system: uric acid-calcium hydroxide -hydrochloric acid-water aged for 2 months at 310 K were studied to determine conditions for calcium hydrogenurate hexahydrate, Ca(C5H3N4O)2 · 6H2O precipitation. The precipitates were identified by chemical and thermogravimetric analyses, x-ray powder diffraction, infrared spectroscopy, light microscopy, and scanning electron microscopy. In the precipitation diagram the concentration region in which calcium hydrogenurate hexahydrate precipitated as a single solid phase was established. The solubility of calcium hydrogenurate hexahydrate was investigated in the pH range from 6.2 to 10.1 at different temperatures. The total soluble and ionic concentration of calcium (atomic absorption spectroscopy and Ca-selective electrode), total urate concentration (spectrophotometry), and pH were determined in equilibrated solutions. The data are presented in the form of tables and chemical potential diagrams. By using these data the thermodynamic solubility products of calcium hydrogenurate hexahydrate, Ks = a(Ca(2+)) · a(2)(C5H3N4O3(-)), were determined: [Formula: see text]The formation of calcium hydrogenurate hexahydrate crystals in urinary tract of patients with pathologically high concentrations of calcium and urates (hypercalciuria and hyperuricosiuria) is possible.

  19. Novel phosphate-activated macrophages prevent ectopic calcification by increasing extracellular ATP and pyrophosphate

    Science.gov (United States)

    Villa-Bellosta, Ricardo; Hamczyk, Magda R.; Andrés, Vicente

    2017-01-01

    Purpose Phosphorus is an essential nutrient involved in many pathobiological processes. Less than 1% of phosphorus is found in extracellular fluids as inorganic phosphate ion (Pi) in solution. High serum Pi level promotes ectopic calcification in many tissues, including blood vessels. Here, we studied the effect of elevated Pi concentration on macrophage polarization and calcification. Macrophages, present in virtually all tissues, play key roles in health and disease and display remarkable plasticity, being able to change their physiology in response to environmental cues. Methods and results High-throughput transcriptomic analysis and functional studies demonstrated that Pi induces unpolarized macrophages to adopt a phenotype closely resembling that of alternatively-activated M2 macrophages, as revealed by arginine hydrolysis and energetic and antioxidant profiles. Pi-induced macrophages showed an anti-calcifying action mediated by increased availability of extracellular ATP and pyrophosphate. Conclusion We conclude that the ability of Pi-activated macrophages to prevent calcium-phosphate deposition is a compensatory mechanism protecting tissues from hyperphosphatemia-induced pathologic calcification. PMID:28362852

  20. Characterization of extracellular matrix macromolecules in primary cultures of equine keratinocytes

    Directory of Open Access Journals (Sweden)

    Pollitt Christopher C

    2010-03-01

    Full Text Available Abstract Background Most research to date involving laminins and extracellular matrix protein function in both normal and pathological conditions involves in vitro culture of keratinocytes. Few methods are established to allow for prolonged propagation of keratinocytes from equine tissues, including the hoof lamellae. In this study we modified cell isolation and culture techniques to allow for proliferation and sub-culturing of equine lamellar keratinocytes. Additionally, the production and processing of extracellular matrix molecules by skin and lamellar keratinocytes were studied. Results Physical and proteolytic tissue separation in combination with media containing a calcium concentration of 0.6 mM in combination with additional media supplements proved optimal for proliferation and subculture of equine lamellar keratinocytes on collagen coated substratum. Immunofluorescence and immunoblotting studies confirmed that equine skin and lamellar keratinocytes produce Ln-332 in vitro and processing of this molecule follows that of other species. As well, matrix components including integrin alpha-6 (α6 and the hemidesmsome proteins, bullous pemphigoid antigen 1 (BP180 bullous pemphigoid antigen 2 (BP230 and plectin are also expressed. Conclusions Isolation of equine keratinocytes and study of the matrix and adhesion related molecules produced by them provides a valuable tool for future work in the veterinary field.

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

    Science.gov (United States)

    Madani, Babak; Mirshekari, Amin; Yahia, Elhadi

    2016-07-01

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

  2. 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.

  3. Molecular and cellular aspects of calcium action in plants

    Science.gov (United States)

    Poovaiah, B. W.

    1988-01-01

    Calcium is known to be a second messenger in many developmental processes in animal systems, but it has only recently become evident that Ca is an important intracellular messenger in plants as well. The level of free Ca concentration in the cytoplasm is extremely low, and it is influenced by extracellular signals such as light, gravity, and hormones. Investigations from our laboratory indicated that Ca and its binding protein, calmodulin, play an important role in stimulus-response coupling by regulating enzyme activities, especially through protein phosphorylation. In vivo and in vitro protein phosphorylation studies have revealed Ca-dependent changes in various plant tissues. We have also been able to influence various physiological processes such as cell elongation, abscission, senescence, and tuberization by altering extracellular and intracellular Ca levels. Other examples of Ca-mediated processes in plants are as follows: a) cell division, b) geotropism, c) protoplasmic streaming, d) stomatal control, e) chloroplast movement, f) secretion, g) hormone-dependent changes, h) enzyme activation, and i) protein phosphorylation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-07-01

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

  5. EXTRACELLULAR POLYSACCHARIDES OF POTATO RING ROT PATHOGEN

    Directory of Open Access Journals (Sweden)

    Shafikova Т.N.

    2006-03-01

    Full Text Available Many bacteria, including phytopathogenic ones produce extracellular polysaccharides or exopolysaccharides which are universal molecules. Causal agent of potato ring rot, Clavibacter michiganensis subspecies sepedonicus, secretes exopolysaccharides which role in pathogenesis is poorly investigated. The aim of our research is to ascertain the composition and structure of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides. Exopolysaccharides of Clavibacter michiganensis subspecies sepedonicus are determined to consist of 4-6 anionic and neutral components which have molecular weights from 700 kDa. Glucose is a major monomer of polysaccharides and arabinose, rhamnose and mannose are minor monomers. Glucose is present in α-Dglucopyranose and β-D-glucopyranose configurations. Calcium is determined to be a component of exopolysaccharides. Components of exopolysaccharides of potato ring rot pathogen are probably capableto associate via calcium ions and other ionic interactions that may result in a change of their physiological activity. Further studies of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides composition and structure can serve a base for the synthesis of their chemical analogues with elicitor action.

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

    Science.gov (United States)

    Thacher, Tom D; Abrams, Steven A

    2010-11-01

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

  7. Calcium D-saccharate

    DEFF Research Database (Denmark)

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

    2016-01-01

    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......-saccharate becomes spontaneously supersaturated with both d-gluconate and d-saccharate calcium salts, from which only calcium d-saccharate slowly precipitates. Calcium d-saccharate is suggested to act as a stabilizer of supersaturated solutions of other calcium hydroxycarboxylates with endothermic complex formation...

  8. R-type calcium channels are crucial for semaphorin 3A-induced DRG axon growth cone collapse.

    Directory of Open Access Journals (Sweden)

    Rimantas Treinys

    Full Text Available Semaphorin 3A (Sema3A is a secreted protein involved in axon path-finding during nervous system development. Calcium signaling plays an important role during axonal growth in response to different guidance cues; however it remains unclear whether this is also the case for Sema3A. In this study we used intracellular calcium imaging to figure out whether Sema3A-induced growth cone collapse is a Ca2+ dependent process. Intracellular Ca2+ imaging results using Fura-2 AM showed Ca2+ increase in E15 mice dorsal root ganglia neurons upon Sema3A treatment. Consequently we analyzed Sema3A effect on growth cones after blocking or modifying intracellular and extracellular Ca2+ channels that are expressed in E15 mouse embryos. Our results demonstrate that Sema3A increased growth cone collapse rate is blocked by the non-selective R- and T- type Ca2+ channel blocker NiCl2 and by the selective R-type Ca2+ channel blocker SNX482. These Ca2+ channel blockers consistently decreased the Sema3A-induced intracellular Ca2+ concentration elevation. Overall, our results demonstrate that Sema3A-induced growth cone collapses are intimately related with increase in intracellular calcium concentration mediated by R-type calcium channels.

  9. Non-ureolytic calcium carbonate precipitation by Lysinibacillus sp. YS11 isolated from the rhizosphere of Miscanthus sacchariflorus.

    Science.gov (United States)

    Lee, Yun Suk; Kim, Hyun Jung; Park, Woojun

    2017-06-01

    Although microbially induced calcium carbonate precipitation (MICP) through ureolysis has been widely studied in environmental engineering fields, urea utilization might cause environmental problems as a result of ammonia and nitrate production. In this study, many non-ureolytic calcium carbonate-precipitating bacteria that induced an alkaline environment were isolated from the rhizosphere of Miscanthus sacchariflorus near an artificial stream and their ability to precipitate calcium carbonate minerals with the absence of urea was investigated. MICP was observed using a phase-contrast microscope and ion-selective electrode. Only Lysinibacillus sp. YS11 showed MICP in aerobic conditions. Energy dispersive X-ray spectrometry and X-ray diffraction confirmed the presence of calcium carbonate. Field emission scanning electron microscopy analysis indicated the formation of morphologically distinct minerals around cells under these conditions. Monitoring of bacterial growth, pH changes, and Ca(2+) concentrations under aerobic, hypoxia, and anaerobic conditions suggested that strain YS11 could induce alkaline conditions up to a pH of 8.9 and utilize 95% of free Ca(2+) only under aerobic conditions. Unusual Ca(2+) binding and its release from cells were observed under hypoxia conditions. Biofilm and extracellular polymeric substances (EPS) formation were enhanced during MICP. Strain YS11 has resistance at high pH and in high salt concentrations, as well as its spore-forming ability, which supports its potential application for self-healing concrete.

  10. Effect of varied ionic calcium on human adipose-derived stem cell mineralization.

    Science.gov (United States)

    McCullen, Seth D; Zhan, Jackie; Onorato, Maureen L; Bernacki, Susan H; Loboa, Elizabeth G

    2010-06-01

    Human adipose-derived stem cells (hASCs) are a relatively abundant and accessible stem cell source with multilineage differentiation capability and have great potential for bone tissue engineering applications. The success of bone tissue engineering is intimately linked with the production of a mineralized matrix that mimics the natural mineral present within native bone. In this study, we examined the effects of ionic calcium levels of 1.8 (normal concentration in cell culture medium), 8, and 16 mM on hASCs seeded in both two-dimensional monolayer and three-dimensional electrospun scaffolds and cultured in either complete growth medium (CGM) or osteogenic differentiation medium (ODM). The impact of calcium supplementation on hASC viability, proliferation, and mineral deposition was determined. hASCs remained viable for all experimental treatments. hASC proliferation increased with the addition of 8 mM Ca(2+) CGM, but decreased for the 16 mM Ca(2+) CGM treatment. Materials deposited by hASCs were analyzed using four techniques: (1) histological staining with Alizarin Red S, (2) calcium quantification, (3) Fourier transform infrared spectroscopy, and (4) wide-angle X-ray diffraction. Mineral deposition was significantly enhanced under both growth and osteogenic medium conditions by increasing extracellular Ca(2+). The greatest mineral deposition occurred in the ODM 8 mM Ca(2+) treatment group. Fourier transform infrared spectroscopy analysis indicated that elevated calcium concentrations of 8 mM Ca(2+) significantly increased both PO(4) amount and PO(4) to protein ratio for ODM. X-ray diffraction indicated that mineral produced with elevated Ca(2+) in both CGM and ODM had a crystalline structure characteristic of hydroxyapatite. Ionic calcium should be considered a potent regulator in hASC mineralization and could serve as a potential treatment for inducing prompt ossification of hASC-seeded scaffolds for bone tissue engineering prior to implantation.

  11. New concepts in calcium-sensing receptor pharmacology and signalling

    OpenAIRE

    Ward, Donald T.; Riccardi, Daniela

    2012-01-01

    The calcium-sensing receptor (CaR) is the key controller of extracellular calcium (Ca2+o) homeostasis via its regulation of parathyroid hormone (PTH) secretion and renal Ca2+ reabsorption. The CaR-selective calcimimetic drug Cinacalcet stimulates the CaR to suppress PTH secretion in chronic kidney disease and represents the world's first clinically available receptor positive allosteric modulator (PAM). Negative CaR allosteric modulators (NAMs), known as calcilytics, can increase PTH secretio...

  12. Níveis de concentrado e sais de cálcio de ácidos graxos para novilhos terminados em confinamento Concentrate levels and calcium salts of fatty acids for feedlot finished steers

    Directory of Open Access Journals (Sweden)

    Regina Célia Cardoso Margarido

    2011-02-01

    Full Text Available Objetivou-se avaliar o efeito do nível de concentrado e dos sais de cálcio de ácidos graxos (SCAG sobre o desempenho e qualidade da carne de novilhos terminados em confinamento. Sessenta novilhos Nelore e cruza Nelore foram divididos em quatro grupos e confinados por um período de 85 dias com as seguintes dietas: (BC 46,7% de concentrado; (BC-SCAG dieta BC acrescida de 3% de SCAG; (AC dieta contendo 76,6% de concentrado e (AC-SCAG dieta AC com 3% de SCAG. O nível de concentrado não influenciou o ganho médio diário, a espessura de gordura subcutânea e a área de olho de lombo, mas as dietas AC aumentaram o peso (P=0,0011 e o rendimento (PThe objective of this research was to evaluate the effects of concentrate level and calcium salts of fatty acids (SCAG on performance and meat quality of feedlot finished steers. Sixty Nellore and Nellore crossbred steers were distributed in four groups and fed for 85 days with one of the following diets: BC diet containing 46.7% of concentrate; (BC-SCAG LC diet plus 3% of SCAG; (AC diet containing 76.6% of concentrate and (AC- SCAG HC diet plus 3% of SCAG. Concentrate level did not affected average daily gain, subcutaneous fat thickness and ribeye area, but AC diets increased carcass weight (P=0.0011, dressing percentage (P<0.0001 and shear force (P=0.0438. SCAG increased average daily gain in AC (P=0.0311 but not in BC diets. Animals fed with SCAG diets showed greater carcass weight (P=0.0133 and dressing percentage (P=0.0160 with no differences on fat thickness, ribeye area and shear force. High concentrate diets and SCAG improved quantitative carcass traits (weight and dressing percentage of finishing cattle and can be used as alternative to improve the efficiency of the production system.

  13. The effects of thioperamide on extracellular levels of glutamate and GABA in the rat prefrontal cortex.

    Science.gov (United States)

    Welty, Natalie; Shoblock, James R

    2009-12-01

    Histamine H3 receptors (H3R) are presynaptic heteroreceptors that negatively modulate the release of histamine and other neurotransmitters such as acetylcholine. Blocking H3 receptors with antagonists/inverse agonists has been shown to be procognitive and this effect has often been associated with increases in acetylcholine transmission. H3 receptors are abundantly expressed in the prefrontal cortex, an area associated with cognitive performance. While the procognitive effects of H3 receptor antagonists/inverse agonists may depend on alterations to acetylcholine or histamine release, other transmitters involved in cognitive processing such as glutamate and gamma-aminobutyric acid (GABA) may also be involved. The purpose of the present study was to examine the effects of thioperamide, an H3 receptor antagonist, on extracellular levels of glutamate and GABA in the prefrontal cortex. By means of in vivo microdialysis on freely moving Sprague Dawley rats, samples were collected and assayed via high-performance liquid chromatography coupled to electrochemical detection. Replacement of calcium with magnesium revealed that the release of GABA, but not glutamate, was calcium-dependent. T